Initial commit

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diff --git a/.gitignore b/.gitignore
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+candy_gear
+doc
+
+*.o
\ No newline at end of file
diff --git a/CODE_OF_CONDUCT.markdown b/CODE_OF_CONDUCT.markdown
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+Benedictine Code of Conduct
+===========================
+
+Summum Bonum
+------------
+
+"Every art and every inquiry, and similarly every action and pursuit, is thought to aim at some good; and for this reason the good has rightly been declared to be that at which all things aim." - Aristotle of Stagira, Nicomachean Ethics
+
+To ensure a healthy development environment and prevent insidious heretical indoctrination through free software projects, participation in the CandyGear is governed towards the highest good.
+
+This project welcomes all Christians and all people that respect Christian values. Therefore, all participants are encouraged to follow the [Recommendations](#Recommendations) section, and everything under the [Rules](#Rules) section will be enforced.
+
+Recommendations
+---------------
+
+01. First of all, love the Lord God with your whole heart, your whole soul, and your whole strength.
+02. Then, love your neighbor as yourself.
+03. Honor all people.
+04. Deny oneself in order to follow Christ.
+05. Chastise the body.
+06. Do not become attached to pleasures.
+07. Love fasting.
+08. Relieve the poor.
+09. Clothe the naked.
+10. Visit the sick.
+11. Bury the dead.
+12. Be a stranger to the world's ways.
+13. Prefer nothing more than the love of Christ.
+14. Do not forsake charity.
+15. Do not return evil for evil.
+16. Do no wrong to anyone, and bear patiently wrongs done to yourself.
+17. Love your enemies.
+18. Do not curse those who curse you, but rather bless them.
+19. Put your hope in God.
+20. Attribute to God, and not to self, whatever good you see in yourself.
+21. Recognize always that evil is your own doing, and to impute it to yourself.
+22. Fear the Day of Judgment.
+23. Be in dread of hell.
+24. Desire eternal life with all the passion of the spirit.
+25. Keep death daily before your eyes.
+26. Keep constant guard over the actions of your life.
+27. Know for certain that God sees you everywhere.
+28. When wrongful thoughts come into your heart, dash them against Christ immediately.
+29. Disclose wrongful thoughts to your spiritual mentor.
+30. Listen willingly to holy reading.
+31. Devote yourself frequently to prayer.
+32. Daily in your prayers, with tears and sighs, confess your past sins to God, and amend them for the future.
+33. Fulfill not the desires of the flesh; hate your own will.
+34. Obey in all things the commands of those whom God has placed in authority over you even though they (which God forbid) should act otherwise, mindful of the Lord's precept, "Do what they say, but not what they do."
+35. Do not wish to be called holy before one is holy; but first to be holy, that you may be truly so called.
+36. Fulfill God's commandments daily in your deeds.
+37. Love chastity.
+38. Hate no one.
+39. Pray for your enemies in the love of Christ.
+40. Make peace with your adversary before the sun sets.
+41. Never despair of God's mercy.
+
+Rules
+-----
+
+01. Do not murder.
+02. Do not commit adultery.
+03. Do not steal.
+04. Do not covet.
+05. Do not bear false witness.
+06. Do not do to another what you would not have done to yourself.
+07. Be a help in times of trouble.
+08. Console the sorrowing.
+09. Do not give way to anger.
+10. Do not nurse a grudge.
+11. Do not entertain deceit in your heart.
+12. Do not give a false peace.
+13. Do not swear, for fear of perjuring yourself.
+14. Utter only truth from heart and mouth.
+15. Bear persecution for justice's sake.
+16. Be not proud.
+17. Be not addicted to wine.
+18. Be not a great eater.
+19. Be not drowsy.
+20. Be not lazy.
+21. Be not a grumbler.
+22. Be not a detractor.
+23. Guard your tongue against evil and depraved speech.
+24. Do not love much talking.
+25. Speak no useless words or words that move to laughter.
+26. Do not love much or boisterous laughter.
+27. Be not jealous, nor harbor envy.
+28. Do not love quarreling.
+29. Shun arrogance.
+30. Respect your seniors.
+31. Love your juniors.
+
+Scope
+-----
+
+These rules apply within every official CandyGear community space and when an individual officially represents the project.
+
+Enforcement
+-----------
+
+The moderators will take one of the following measurements to violations of the [Rules](#Rules):
+
+- remove or replace any irregular content with one more appropriated;
+- warnings when the violations are minor or mild;
+- in case of grave infringement, a temporary banishment from 1 to 3 months;
+- in case of grave infringement from a person that already received a banish, a banishment from 6 months to 2 years.
+
+Reporting
+---------
+
+Any infringement of the [Rules](#Rules) can be reported at <fred@linhares.blue>. The moderators will promptly and thoroughly investigate all complaints.
diff --git a/Doxyfile b/Doxyfile
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index 0000000..044e484
--- /dev/null
+++ b/Doxyfile
@@ -0,0 +1,2618 @@
+# Doxyfile 1.9.3
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+#---------------------------------------------------------------------------
+
+# If the EXTRACT_ALL tag is set to YES, doxygen will assume all entities in
+# documentation are documented, even if no documentation was available. Private
+# class members and static file members will be hidden unless the
+# EXTRACT_PRIVATE respectively EXTRACT_STATIC tags are set to YES.
+# Note: This will also disable the warnings about undocumented members that are
+# normally produced when WARNINGS is set to YES.
+# The default value is: NO.
+
+EXTRACT_ALL            = NO
+
+# If the EXTRACT_PRIVATE tag is set to YES, all private members of a class will
+# be included in the documentation.
+# The default value is: NO.
+
+EXTRACT_PRIVATE        = NO
+
+# If the EXTRACT_PRIV_VIRTUAL tag is set to YES, documented private virtual
+# methods of a class will be included in the documentation.
+# The default value is: NO.
+
+EXTRACT_PRIV_VIRTUAL   = NO
+
+# If the EXTRACT_PACKAGE tag is set to YES, all members with package or internal
+# scope will be included in the documentation.
+# The default value is: NO.
+
+EXTRACT_PACKAGE        = NO
+
+# If the EXTRACT_STATIC tag is set to YES, all static members of a file will be
+# included in the documentation.
+# The default value is: NO.
+
+EXTRACT_STATIC         = NO
+
+# If the EXTRACT_LOCAL_CLASSES tag is set to YES, classes (and structs) defined
+# locally in source files will be included in the documentation. If set to NO,
+# only classes defined in header files are included. Does not have any effect
+# for Java sources.
+# The default value is: YES.
+
+EXTRACT_LOCAL_CLASSES  = YES
+
+# This flag is only useful for Objective-C code. If set to YES, local methods,
+# which are defined in the implementation section but not in the interface are
+# included in the documentation. If set to NO, only methods in the interface are
+# included.
+# The default value is: NO.
+
+EXTRACT_LOCAL_METHODS  = NO
+
+# If this flag is set to YES, the members of anonymous namespaces will be
+# extracted and appear in the documentation as a namespace called
+# 'anonymous_namespace{file}', where file will be replaced with the base name of
+# the file that contains the anonymous namespace. By default anonymous namespace
+# are hidden.
+# The default value is: NO.
+
+EXTRACT_ANON_NSPACES   = NO
+
+# If this flag is set to YES, the name of an unnamed parameter in a declaration
+# will be determined by the corresponding definition. By default unnamed
+# parameters remain unnamed in the output.
+# The default value is: YES.
+
+RESOLVE_UNNAMED_PARAMS = YES
+
+# If the HIDE_UNDOC_MEMBERS tag is set to YES, doxygen will hide all
+# undocumented members inside documented classes or files. If set to NO these
+# members will be included in the various overviews, but no documentation
+# section is generated. This option has no effect if EXTRACT_ALL is enabled.
+# The default value is: NO.
+
+HIDE_UNDOC_MEMBERS     = NO
+
+# If the HIDE_UNDOC_CLASSES tag is set to YES, doxygen will hide all
+# undocumented classes that are normally visible in the class hierarchy. If set
+# to NO, these classes will be included in the various overviews. This option
+# has no effect if EXTRACT_ALL is enabled.
+# The default value is: NO.
+
+HIDE_UNDOC_CLASSES     = NO
+
+# If the HIDE_FRIEND_COMPOUNDS tag is set to YES, doxygen will hide all friend
+# declarations. If set to NO, these declarations will be included in the
+# documentation.
+# The default value is: NO.
+
+HIDE_FRIEND_COMPOUNDS  = NO
+
+# If the HIDE_IN_BODY_DOCS tag is set to YES, doxygen will hide any
+# documentation blocks found inside the body of a function. If set to NO, these
+# blocks will be appended to the function's detailed documentation block.
+# The default value is: NO.
+
+HIDE_IN_BODY_DOCS      = NO
+
+# The INTERNAL_DOCS tag determines if documentation that is typed after a
+# \internal command is included. If the tag is set to NO then the documentation
+# will be excluded. Set it to YES to include the internal documentation.
+# The default value is: NO.
+
+INTERNAL_DOCS          = NO
+
+# With the correct setting of option CASE_SENSE_NAMES doxygen will better be
+# able to match the capabilities of the underlying filesystem. In case the
+# filesystem is case sensitive (i.e. it supports files in the same directory
+# whose names only differ in casing), the option must be set to YES to properly
+# deal with such files in case they appear in the input. For filesystems that
+# are not case sensitive the option should be be set to NO to properly deal with
+# output files written for symbols that only differ in casing, such as for two
+# classes, one named CLASS and the other named Class, and to also support
+# references to files without having to specify the exact matching casing. On
+# Windows (including Cygwin) and MacOS, users should typically set this option
+# to NO, whereas on Linux or other Unix flavors it should typically be set to
+# YES.
+# The default value is: system dependent.
+
+CASE_SENSE_NAMES       = YES
+
+# If the HIDE_SCOPE_NAMES tag is set to NO then doxygen will show members with
+# their full class and namespace scopes in the documentation. If set to YES, the
+# scope will be hidden.
+# The default value is: NO.
+
+HIDE_SCOPE_NAMES       = NO
+
+# If the HIDE_COMPOUND_REFERENCE tag is set to NO (default) then doxygen will
+# append additional text to a page's title, such as Class Reference. If set to
+# YES the compound reference will be hidden.
+# The default value is: NO.
+
+HIDE_COMPOUND_REFERENCE= NO
+
+# If the SHOW_HEADERFILE tag is set to YES then the documentation for a class
+# will show which file needs to be included to use the class.
+# The default value is: YES.
+
+SHOW_HEADERFILE        = YES
+
+# If the SHOW_INCLUDE_FILES tag is set to YES then doxygen will put a list of
+# the files that are included by a file in the documentation of that file.
+# The default value is: YES.
+
+SHOW_INCLUDE_FILES     = YES
+
+# If the SHOW_GROUPED_MEMB_INC tag is set to YES then Doxygen will add for each
+# grouped member an include statement to the documentation, telling the reader
+# which file to include in order to use the member.
+# The default value is: NO.
+
+SHOW_GROUPED_MEMB_INC  = NO
+
+# If the FORCE_LOCAL_INCLUDES tag is set to YES then doxygen will list include
+# files with double quotes in the documentation rather than with sharp brackets.
+# The default value is: NO.
+
+FORCE_LOCAL_INCLUDES   = NO
+
+# If the INLINE_INFO tag is set to YES then a tag [inline] is inserted in the
+# documentation for inline members.
+# The default value is: YES.
+
+INLINE_INFO            = YES
+
+# If the SORT_MEMBER_DOCS tag is set to YES then doxygen will sort the
+# (detailed) documentation of file and class members alphabetically by member
+# name. If set to NO, the members will appear in declaration order.
+# The default value is: YES.
+
+SORT_MEMBER_DOCS       = YES
+
+# If the SORT_BRIEF_DOCS tag is set to YES then doxygen will sort the brief
+# descriptions of file, namespace and class members alphabetically by member
+# name. If set to NO, the members will appear in declaration order. Note that
+# this will also influence the order of the classes in the class list.
+# The default value is: NO.
+
+SORT_BRIEF_DOCS        = NO
+
+# If the SORT_MEMBERS_CTORS_1ST tag is set to YES then doxygen will sort the
+# (brief and detailed) documentation of class members so that constructors and
+# destructors are listed first. If set to NO the constructors will appear in the
+# respective orders defined by SORT_BRIEF_DOCS and SORT_MEMBER_DOCS.
+# Note: If SORT_BRIEF_DOCS is set to NO this option is ignored for sorting brief
+# member documentation.
+# Note: If SORT_MEMBER_DOCS is set to NO this option is ignored for sorting
+# detailed member documentation.
+# The default value is: NO.
+
+SORT_MEMBERS_CTORS_1ST = NO
+
+# If the SORT_GROUP_NAMES tag is set to YES then doxygen will sort the hierarchy
+# of group names into alphabetical order. If set to NO the group names will
+# appear in their defined order.
+# The default value is: NO.
+
+SORT_GROUP_NAMES       = NO
+
+# If the SORT_BY_SCOPE_NAME tag is set to YES, the class list will be sorted by
+# fully-qualified names, including namespaces. If set to NO, the class list will
+# be sorted only by class name, not including the namespace part.
+# Note: This option is not very useful if HIDE_SCOPE_NAMES is set to YES.
+# Note: This option applies only to the class list, not to the alphabetical
+# list.
+# The default value is: NO.
+
+SORT_BY_SCOPE_NAME     = NO
+
+# If the STRICT_PROTO_MATCHING option is enabled and doxygen fails to do proper
+# type resolution of all parameters of a function it will reject a match between
+# the prototype and the implementation of a member function even if there is
+# only one candidate or it is obvious which candidate to choose by doing a
+# simple string match. By disabling STRICT_PROTO_MATCHING doxygen will still
+# accept a match between prototype and implementation in such cases.
+# The default value is: NO.
+
+STRICT_PROTO_MATCHING  = NO
+
+# The GENERATE_TODOLIST tag can be used to enable (YES) or disable (NO) the todo
+# list. This list is created by putting \todo commands in the documentation.
+# The default value is: YES.
+
+GENERATE_TODOLIST      = YES
+
+# The GENERATE_TESTLIST tag can be used to enable (YES) or disable (NO) the test
+# list. This list is created by putting \test commands in the documentation.
+# The default value is: YES.
+
+GENERATE_TESTLIST      = YES
+
+# The GENERATE_BUGLIST tag can be used to enable (YES) or disable (NO) the bug
+# list. This list is created by putting \bug commands in the documentation.
+# The default value is: YES.
+
+GENERATE_BUGLIST       = YES
+
+# The GENERATE_DEPRECATEDLIST tag can be used to enable (YES) or disable (NO)
+# the deprecated list. This list is created by putting \deprecated commands in
+# the documentation.
+# The default value is: YES.
+
+GENERATE_DEPRECATEDLIST= YES
+
+# The ENABLED_SECTIONS tag can be used to enable conditional documentation
+# sections, marked by \if <section_label> ... \endif and \cond <section_label>
+# ... \endcond blocks.
+
+ENABLED_SECTIONS       =
+
+# The MAX_INITIALIZER_LINES tag determines the maximum number of lines that the
+# initial value of a variable or macro / define can have for it to appear in the
+# documentation. If the initializer consists of more lines than specified here
+# it will be hidden. Use a value of 0 to hide initializers completely. The
+# appearance of the value of individual variables and macros / defines can be
+# controlled using \showinitializer or \hideinitializer command in the
+# documentation regardless of this setting.
+# Minimum value: 0, maximum value: 10000, default value: 30.
+
+MAX_INITIALIZER_LINES  = 30
+
+# Set the SHOW_USED_FILES tag to NO to disable the list of files generated at
+# the bottom of the documentation of classes and structs. If set to YES, the
+# list will mention the files that were used to generate the documentation.
+# The default value is: YES.
+
+SHOW_USED_FILES        = YES
+
+# Set the SHOW_FILES tag to NO to disable the generation of the Files page. This
+# will remove the Files entry from the Quick Index and from the Folder Tree View
+# (if specified).
+# The default value is: YES.
+
+SHOW_FILES             = YES
+
+# Set the SHOW_NAMESPACES tag to NO to disable the generation of the Namespaces
+# page. This will remove the Namespaces entry from the Quick Index and from the
+# Folder Tree View (if specified).
+# The default value is: YES.
+
+SHOW_NAMESPACES        = YES
+
+# The FILE_VERSION_FILTER tag can be used to specify a program or script that
+# doxygen should invoke to get the current version for each file (typically from
+# the version control system). Doxygen will invoke the program by executing (via
+# popen()) the command command input-file, where command is the value of the
+# FILE_VERSION_FILTER tag, and input-file is the name of an input file provided
+# by doxygen. Whatever the program writes to standard output is used as the file
+# version. For an example see the documentation.
+
+FILE_VERSION_FILTER    =
+
+# The LAYOUT_FILE tag can be used to specify a layout file which will be parsed
+# by doxygen. The layout file controls the global structure of the generated
+# output files in an output format independent way. To create the layout file
+# that represents doxygen's defaults, run doxygen with the -l option. You can
+# optionally specify a file name after the option, if omitted DoxygenLayout.xml
+# will be used as the name of the layout file. See also section "Changing the
+# layout of pages" for information.
+#
+# Note that if you run doxygen from a directory containing a file called
+# DoxygenLayout.xml, doxygen will parse it automatically even if the LAYOUT_FILE
+# tag is left empty.
+
+LAYOUT_FILE            =
+
+# The CITE_BIB_FILES tag can be used to specify one or more bib files containing
+# the reference definitions. This must be a list of .bib files. The .bib
+# extension is automatically appended if omitted. This requires the bibtex tool
+# to be installed. See also https://en.wikipedia.org/wiki/BibTeX for more info.
+# For LaTeX the style of the bibliography can be controlled using
+# LATEX_BIB_STYLE. To use this feature you need bibtex and perl available in the
+# search path. See also \cite for info how to create references.
+
+CITE_BIB_FILES         =
+
+#---------------------------------------------------------------------------
+# Configuration options related to warning and progress messages
+#---------------------------------------------------------------------------
+
+# The QUIET tag can be used to turn on/off the messages that are generated to
+# standard output by doxygen. If QUIET is set to YES this implies that the
+# messages are off.
+# The default value is: NO.
+
+QUIET                  = NO
+
+# The WARNINGS tag can be used to turn on/off the warning messages that are
+# generated to standard error (stderr) by doxygen. If WARNINGS is set to YES
+# this implies that the warnings are on.
+#
+# Tip: Turn warnings on while writing the documentation.
+# The default value is: YES.
+
+WARNINGS               = YES
+
+# If the WARN_IF_UNDOCUMENTED tag is set to YES then doxygen will generate
+# warnings for undocumented members. If EXTRACT_ALL is set to YES then this flag
+# will automatically be disabled.
+# The default value is: YES.
+
+WARN_IF_UNDOCUMENTED   = YES
+
+# If the WARN_IF_DOC_ERROR tag is set to YES, doxygen will generate warnings for
+# potential errors in the documentation, such as documenting some parameters in
+# a documented function twice, or documenting parameters that don't exist or
+# using markup commands wrongly.
+# The default value is: YES.
+
+WARN_IF_DOC_ERROR      = YES
+
+# If WARN_IF_INCOMPLETE_DOC is set to YES, doxygen will warn about incomplete
+# function parameter documentation. If set to NO, doxygen will accept that some
+# parameters have no documentation without warning.
+# The default value is: YES.
+
+WARN_IF_INCOMPLETE_DOC = YES
+
+# This WARN_NO_PARAMDOC option can be enabled to get warnings for functions that
+# are documented, but have no documentation for their parameters or return
+# value. If set to NO, doxygen will only warn about wrong parameter
+# documentation, but not about the absence of documentation. If EXTRACT_ALL is
+# set to YES then this flag will automatically be disabled. See also
+# WARN_IF_INCOMPLETE_DOC
+# The default value is: NO.
+
+WARN_NO_PARAMDOC       = NO
+
+# If the WARN_AS_ERROR tag is set to YES then doxygen will immediately stop when
+# a warning is encountered. If the WARN_AS_ERROR tag is set to FAIL_ON_WARNINGS
+# then doxygen will continue running as if WARN_AS_ERROR tag is set to NO, but
+# at the end of the doxygen process doxygen will return with a non-zero status.
+# Possible values are: NO, YES and FAIL_ON_WARNINGS.
+# The default value is: NO.
+
+WARN_AS_ERROR          = NO
+
+# The WARN_FORMAT tag determines the format of the warning messages that doxygen
+# can produce. The string should contain the $file, $line, and $text tags, which
+# will be replaced by the file and line number from which the warning originated
+# and the warning text. Optionally the format may contain $version, which will
+# be replaced by the version of the file (if it could be obtained via
+# FILE_VERSION_FILTER)
+# The default value is: $file:$line: $text.
+
+WARN_FORMAT            = "$file:$line: $text"
+
+# The WARN_LOGFILE tag can be used to specify a file to which warning and error
+# messages should be written. If left blank the output is written to standard
+# error (stderr). In case the file specified cannot be opened for writing the
+# warning and error messages are written to standard error. When as file - is
+# specified the warning and error messages are written to standard output
+# (stdout).
+
+WARN_LOGFILE           =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the input files
+#---------------------------------------------------------------------------
+
+# The INPUT tag is used to specify the files and/or directories that contain
+# documented source files. You may enter file names like myfile.cpp or
+# directories like /usr/src/myproject. Separate the files or directories with
+# spaces. See also FILE_PATTERNS and EXTENSION_MAPPING
+# Note: If this tag is empty the current directory is searched.
+
+INPUT                  = src
+
+# This tag can be used to specify the character encoding of the source files
+# that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses
+# libiconv (or the iconv built into libc) for the transcoding. See the libiconv
+# documentation (see:
+# https://www.gnu.org/software/libiconv/) for the list of possible encodings.
+# The default value is: UTF-8.
+
+INPUT_ENCODING         = UTF-8
+
+# If the value of the INPUT tag contains directories, you can use the
+# FILE_PATTERNS tag to specify one or more wildcard patterns (like *.cpp and
+# *.h) to filter out the source-files in the directories.
+#
+# Note that for custom extensions or not directly supported extensions you also
+# need to set EXTENSION_MAPPING for the extension otherwise the files are not
+# read by doxygen.
+#
+# Note the list of default checked file patterns might differ from the list of
+# default file extension mappings.
+#
+# If left blank the following patterns are tested:*.c, *.cc, *.cxx, *.cpp,
+# *.c++, *.java, *.ii, *.ixx, *.ipp, *.i++, *.inl, *.idl, *.ddl, *.odl, *.h,
+# *.hh, *.hxx, *.hpp, *.h++, *.l, *.cs, *.d, *.php, *.php4, *.php5, *.phtml,
+# *.inc, *.m, *.markdown, *.md, *.mm, *.dox (to be provided as doxygen C
+# comment), *.py, *.pyw, *.f90, *.f95, *.f03, *.f08, *.f18, *.f, *.for, *.vhd,
+# *.vhdl, *.ucf, *.qsf and *.ice.
+
+FILE_PATTERNS          = *.c \
+                         *.cpp \
+                         *.h \
+                         *.hpp \
+                         *.markdown \
+                         *.md \
+
+# The RECURSIVE tag can be used to specify whether or not subdirectories should
+# be searched for input files as well.
+# The default value is: NO.
+
+RECURSIVE              = YES
+
+# The EXCLUDE tag can be used to specify files and/or directories that should be
+# excluded from the INPUT source files. This way you can easily exclude a
+# subdirectory from a directory tree whose root is specified with the INPUT tag.
+#
+# Note that relative paths are relative to the directory from which doxygen is
+# run.
+
+EXCLUDE                =
+
+# The EXCLUDE_SYMLINKS tag can be used to select whether or not files or
+# directories that are symbolic links (a Unix file system feature) are excluded
+# from the input.
+# The default value is: NO.
+
+EXCLUDE_SYMLINKS       = NO
+
+# If the value of the INPUT tag contains directories, you can use the
+# EXCLUDE_PATTERNS tag to specify one or more wildcard patterns to exclude
+# certain files from those directories.
+#
+# Note that the wildcards are matched against the file with absolute path, so to
+# exclude all test directories for example use the pattern */test/*
+
+EXCLUDE_PATTERNS       =
+
+# The EXCLUDE_SYMBOLS tag can be used to specify one or more symbol names
+# (namespaces, classes, functions, etc.) that should be excluded from the
+# output. The symbol name can be a fully qualified name, a word, or if the
+# wildcard * is used, a substring. Examples: ANamespace, AClass,
+# ANamespace::AClass, ANamespace::*Test
+#
+# Note that the wildcards are matched against the file with absolute path, so to
+# exclude all test directories use the pattern */test/*
+
+EXCLUDE_SYMBOLS        =
+
+# The EXAMPLE_PATH tag can be used to specify one or more files or directories
+# that contain example code fragments that are included (see the \include
+# command).
+
+EXAMPLE_PATH           =
+
+# If the value of the EXAMPLE_PATH tag contains directories, you can use the
+# EXAMPLE_PATTERNS tag to specify one or more wildcard pattern (like *.cpp and
+# *.h) to filter out the source-files in the directories. If left blank all
+# files are included.
+
+EXAMPLE_PATTERNS       = *
+
+# If the EXAMPLE_RECURSIVE tag is set to YES then subdirectories will be
+# searched for input files to be used with the \include or \dontinclude commands
+# irrespective of the value of the RECURSIVE tag.
+# The default value is: NO.
+
+EXAMPLE_RECURSIVE      = NO
+
+# The IMAGE_PATH tag can be used to specify one or more files or directories
+# that contain images that are to be included in the documentation (see the
+# \image command).
+
+IMAGE_PATH             =
+
+# The INPUT_FILTER tag can be used to specify a program that doxygen should
+# invoke to filter for each input file. Doxygen will invoke the filter program
+# by executing (via popen()) the command:
+#
+# <filter> <input-file>
+#
+# where <filter> is the value of the INPUT_FILTER tag, and <input-file> is the
+# name of an input file. Doxygen will then use the output that the filter
+# program writes to standard output. If FILTER_PATTERNS is specified, this tag
+# will be ignored.
+#
+# Note that the filter must not add or remove lines; it is applied before the
+# code is scanned, but not when the output code is generated. If lines are added
+# or removed, the anchors will not be placed correctly.
+#
+# Note that for custom extensions or not directly supported extensions you also
+# need to set EXTENSION_MAPPING for the extension otherwise the files are not
+# properly processed by doxygen.
+
+INPUT_FILTER           =
+
+# The FILTER_PATTERNS tag can be used to specify filters on a per file pattern
+# basis. Doxygen will compare the file name with each pattern and apply the
+# filter if there is a match. The filters are a list of the form: pattern=filter
+# (like *.cpp=my_cpp_filter). See INPUT_FILTER for further information on how
+# filters are used. If the FILTER_PATTERNS tag is empty or if none of the
+# patterns match the file name, INPUT_FILTER is applied.
+#
+# Note that for custom extensions or not directly supported extensions you also
+# need to set EXTENSION_MAPPING for the extension otherwise the files are not
+# properly processed by doxygen.
+
+FILTER_PATTERNS        =
+
+# If the FILTER_SOURCE_FILES tag is set to YES, the input filter (if set using
+# INPUT_FILTER) will also be used to filter the input files that are used for
+# producing the source files to browse (i.e. when SOURCE_BROWSER is set to YES).
+# The default value is: NO.
+
+FILTER_SOURCE_FILES    = NO
+
+# The FILTER_SOURCE_PATTERNS tag can be used to specify source filters per file
+# pattern. A pattern will override the setting for FILTER_PATTERN (if any) and
+# it is also possible to disable source filtering for a specific pattern using
+# *.ext= (so without naming a filter).
+# This tag requires that the tag FILTER_SOURCE_FILES is set to YES.
+
+FILTER_SOURCE_PATTERNS =
+
+# If the USE_MDFILE_AS_MAINPAGE tag refers to the name of a markdown file that
+# is part of the input, its contents will be placed on the main page
+# (index.html). This can be useful if you have a project on for instance GitHub
+# and want to reuse the introduction page also for the doxygen output.
+
+USE_MDFILE_AS_MAINPAGE =
+
+#---------------------------------------------------------------------------
+# Configuration options related to source browsing
+#---------------------------------------------------------------------------
+
+# If the SOURCE_BROWSER tag is set to YES then a list of source files will be
+# generated. Documented entities will be cross-referenced with these sources.
+#
+# Note: To get rid of all source code in the generated output, make sure that
+# also VERBATIM_HEADERS is set to NO.
+# The default value is: NO.
+
+SOURCE_BROWSER         = NO
+
+# Setting the INLINE_SOURCES tag to YES will include the body of functions,
+# classes and enums directly into the documentation.
+# The default value is: NO.
+
+INLINE_SOURCES         = NO
+
+# Setting the STRIP_CODE_COMMENTS tag to YES will instruct doxygen to hide any
+# special comment blocks from generated source code fragments. Normal C, C++ and
+# Fortran comments will always remain visible.
+# The default value is: YES.
+
+STRIP_CODE_COMMENTS    = YES
+
+# If the REFERENCED_BY_RELATION tag is set to YES then for each documented
+# entity all documented functions referencing it will be listed.
+# The default value is: NO.
+
+REFERENCED_BY_RELATION = NO
+
+# If the REFERENCES_RELATION tag is set to YES then for each documented function
+# all documented entities called/used by that function will be listed.
+# The default value is: NO.
+
+REFERENCES_RELATION    = NO
+
+# If the REFERENCES_LINK_SOURCE tag is set to YES and SOURCE_BROWSER tag is set
+# to YES then the hyperlinks from functions in REFERENCES_RELATION and
+# REFERENCED_BY_RELATION lists will link to the source code. Otherwise they will
+# link to the documentation.
+# The default value is: YES.
+
+REFERENCES_LINK_SOURCE = YES
+
+# If SOURCE_TOOLTIPS is enabled (the default) then hovering a hyperlink in the
+# source code will show a tooltip with additional information such as prototype,
+# brief description and links to the definition and documentation. Since this
+# will make the HTML file larger and loading of large files a bit slower, you
+# can opt to disable this feature.
+# The default value is: YES.
+# This tag requires that the tag SOURCE_BROWSER is set to YES.
+
+SOURCE_TOOLTIPS        = YES
+
+# If the USE_HTAGS tag is set to YES then the references to source code will
+# point to the HTML generated by the htags(1) tool instead of doxygen built-in
+# source browser. The htags tool is part of GNU's global source tagging system
+# (see https://www.gnu.org/software/global/global.html). You will need version
+# 4.8.6 or higher.
+#
+# To use it do the following:
+# - Install the latest version of global
+# - Enable SOURCE_BROWSER and USE_HTAGS in the configuration file
+# - Make sure the INPUT points to the root of the source tree
+# - Run doxygen as normal
+#
+# Doxygen will invoke htags (and that will in turn invoke gtags), so these
+# tools must be available from the command line (i.e. in the search path).
+#
+# The result: instead of the source browser generated by doxygen, the links to
+# source code will now point to the output of htags.
+# The default value is: NO.
+# This tag requires that the tag SOURCE_BROWSER is set to YES.
+
+USE_HTAGS              = NO
+
+# If the VERBATIM_HEADERS tag is set the YES then doxygen will generate a
+# verbatim copy of the header file for each class for which an include is
+# specified. Set to NO to disable this.
+# See also: Section \class.
+# The default value is: YES.
+
+VERBATIM_HEADERS       = YES
+
+#---------------------------------------------------------------------------
+# Configuration options related to the alphabetical class index
+#---------------------------------------------------------------------------
+
+# If the ALPHABETICAL_INDEX tag is set to YES, an alphabetical index of all
+# compounds will be generated. Enable this if the project contains a lot of
+# classes, structs, unions or interfaces.
+# The default value is: YES.
+
+ALPHABETICAL_INDEX     = YES
+
+# In case all classes in a project start with a common prefix, all classes will
+# be put under the same header in the alphabetical index. The IGNORE_PREFIX tag
+# can be used to specify a prefix (or a list of prefixes) that should be ignored
+# while generating the index headers.
+# This tag requires that the tag ALPHABETICAL_INDEX is set to YES.
+
+IGNORE_PREFIX          =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the HTML output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_HTML tag is set to YES, doxygen will generate HTML output
+# The default value is: YES.
+
+GENERATE_HTML          = YES
+
+# The HTML_OUTPUT tag is used to specify where the HTML docs will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it.
+# The default directory is: html.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_OUTPUT            = html
+
+# The HTML_FILE_EXTENSION tag can be used to specify the file extension for each
+# generated HTML page (for example: .htm, .php, .asp).
+# The default value is: .html.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_FILE_EXTENSION    = .html
+
+# The HTML_HEADER tag can be used to specify a user-defined HTML header file for
+# each generated HTML page. If the tag is left blank doxygen will generate a
+# standard header.
+#
+# To get valid HTML the header file that includes any scripts and style sheets
+# that doxygen needs, which is dependent on the configuration options used (e.g.
+# the setting GENERATE_TREEVIEW). It is highly recommended to start with a
+# default header using
+# doxygen -w html new_header.html new_footer.html new_stylesheet.css
+# YourConfigFile
+# and then modify the file new_header.html. See also section "Doxygen usage"
+# for information on how to generate the default header that doxygen normally
+# uses.
+# Note: The header is subject to change so you typically have to regenerate the
+# default header when upgrading to a newer version of doxygen. For a description
+# of the possible markers and block names see the documentation.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_HEADER            =
+
+# The HTML_FOOTER tag can be used to specify a user-defined HTML footer for each
+# generated HTML page. If the tag is left blank doxygen will generate a standard
+# footer. See HTML_HEADER for more information on how to generate a default
+# footer and what special commands can be used inside the footer. See also
+# section "Doxygen usage" for information on how to generate the default footer
+# that doxygen normally uses.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_FOOTER            =
+
+# The HTML_STYLESHEET tag can be used to specify a user-defined cascading style
+# sheet that is used by each HTML page. It can be used to fine-tune the look of
+# the HTML output. If left blank doxygen will generate a default style sheet.
+# See also section "Doxygen usage" for information on how to generate the style
+# sheet that doxygen normally uses.
+# Note: It is recommended to use HTML_EXTRA_STYLESHEET instead of this tag, as
+# it is more robust and this tag (HTML_STYLESHEET) will in the future become
+# obsolete.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_STYLESHEET        =
+
+# The HTML_EXTRA_STYLESHEET tag can be used to specify additional user-defined
+# cascading style sheets that are included after the standard style sheets
+# created by doxygen. Using this option one can overrule certain style aspects.
+# This is preferred over using HTML_STYLESHEET since it does not replace the
+# standard style sheet and is therefore more robust against future updates.
+# Doxygen will copy the style sheet files to the output directory.
+# Note: The order of the extra style sheet files is of importance (e.g. the last
+# style sheet in the list overrules the setting of the previous ones in the
+# list). For an example see the documentation.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_EXTRA_STYLESHEET  =
+
+# The HTML_EXTRA_FILES tag can be used to specify one or more extra images or
+# other source files which should be copied to the HTML output directory. Note
+# that these files will be copied to the base HTML output directory. Use the
+# $relpath^ marker in the HTML_HEADER and/or HTML_FOOTER files to load these
+# files. In the HTML_STYLESHEET file, use the file name only. Also note that the
+# files will be copied as-is; there are no commands or markers available.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_EXTRA_FILES       =
+
+# The HTML_COLORSTYLE_HUE tag controls the color of the HTML output. Doxygen
+# will adjust the colors in the style sheet and background images according to
+# this color. Hue is specified as an angle on a color-wheel, see
+# https://en.wikipedia.org/wiki/Hue for more information. For instance the value
+# 0 represents red, 60 is yellow, 120 is green, 180 is cyan, 240 is blue, 300
+# purple, and 360 is red again.
+# Minimum value: 0, maximum value: 359, default value: 220.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_COLORSTYLE_HUE    = 220
+
+# The HTML_COLORSTYLE_SAT tag controls the purity (or saturation) of the colors
+# in the HTML output. For a value of 0 the output will use gray-scales only. A
+# value of 255 will produce the most vivid colors.
+# Minimum value: 0, maximum value: 255, default value: 100.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_COLORSTYLE_SAT    = 100
+
+# The HTML_COLORSTYLE_GAMMA tag controls the gamma correction applied to the
+# luminance component of the colors in the HTML output. Values below 100
+# gradually make the output lighter, whereas values above 100 make the output
+# darker. The value divided by 100 is the actual gamma applied, so 80 represents
+# a gamma of 0.8, The value 220 represents a gamma of 2.2, and 100 does not
+# change the gamma.
+# Minimum value: 40, maximum value: 240, default value: 80.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_COLORSTYLE_GAMMA  = 80
+
+# If the HTML_TIMESTAMP tag is set to YES then the footer of each generated HTML
+# page will contain the date and time when the page was generated. Setting this
+# to YES can help to show when doxygen was last run and thus if the
+# documentation is up to date.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_TIMESTAMP         = NO
+
+# If the HTML_DYNAMIC_MENUS tag is set to YES then the generated HTML
+# documentation will contain a main index with vertical navigation menus that
+# are dynamically created via JavaScript. If disabled, the navigation index will
+# consists of multiple levels of tabs that are statically embedded in every HTML
+# page. Disable this option to support browsers that do not have JavaScript,
+# like the Qt help browser.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_DYNAMIC_MENUS     = YES
+
+# If the HTML_DYNAMIC_SECTIONS tag is set to YES then the generated HTML
+# documentation will contain sections that can be hidden and shown after the
+# page has loaded.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_DYNAMIC_SECTIONS  = NO
+
+# With HTML_INDEX_NUM_ENTRIES one can control the preferred number of entries
+# shown in the various tree structured indices initially; the user can expand
+# and collapse entries dynamically later on. Doxygen will expand the tree to
+# such a level that at most the specified number of entries are visible (unless
+# a fully collapsed tree already exceeds this amount). So setting the number of
+# entries 1 will produce a full collapsed tree by default. 0 is a special value
+# representing an infinite number of entries and will result in a full expanded
+# tree by default.
+# Minimum value: 0, maximum value: 9999, default value: 100.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_INDEX_NUM_ENTRIES = 100
+
+# If the GENERATE_DOCSET tag is set to YES, additional index files will be
+# generated that can be used as input for Apple's Xcode 3 integrated development
+# environment (see:
+# https://developer.apple.com/xcode/), introduced with OSX 10.5 (Leopard). To
+# create a documentation set, doxygen will generate a Makefile in the HTML
+# output directory. Running make will produce the docset in that directory and
+# running make install will install the docset in
+# ~/Library/Developer/Shared/Documentation/DocSets so that Xcode will find it at
+# startup. See https://developer.apple.com/library/archive/featuredarticles/Doxy
+# genXcode/_index.html for more information.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_DOCSET        = NO
+
+# This tag determines the name of the docset feed. A documentation feed provides
+# an umbrella under which multiple documentation sets from a single provider
+# (such as a company or product suite) can be grouped.
+# The default value is: Doxygen generated docs.
+# This tag requires that the tag GENERATE_DOCSET is set to YES.
+
+DOCSET_FEEDNAME        = "Doxygen generated docs"
+
+# This tag determines the URL of the docset feed. A documentation feed provides
+# an umbrella under which multiple documentation sets from a single provider
+# (such as a company or product suite) can be grouped.
+# This tag requires that the tag GENERATE_DOCSET is set to YES.
+
+DOCSET_FEEDURL         =
+
+# This tag specifies a string that should uniquely identify the documentation
+# set bundle. This should be a reverse domain-name style string, e.g.
+# com.mycompany.MyDocSet. Doxygen will append .docset to the name.
+# The default value is: org.doxygen.Project.
+# This tag requires that the tag GENERATE_DOCSET is set to YES.
+
+DOCSET_BUNDLE_ID       = org.doxygen.Project
+
+# The DOCSET_PUBLISHER_ID tag specifies a string that should uniquely identify
+# the documentation publisher. This should be a reverse domain-name style
+# string, e.g. com.mycompany.MyDocSet.documentation.
+# The default value is: org.doxygen.Publisher.
+# This tag requires that the tag GENERATE_DOCSET is set to YES.
+
+DOCSET_PUBLISHER_ID    = org.doxygen.Publisher
+
+# The DOCSET_PUBLISHER_NAME tag identifies the documentation publisher.
+# The default value is: Publisher.
+# This tag requires that the tag GENERATE_DOCSET is set to YES.
+
+DOCSET_PUBLISHER_NAME  = Publisher
+
+# If the GENERATE_HTMLHELP tag is set to YES then doxygen generates three
+# additional HTML index files: index.hhp, index.hhc, and index.hhk. The
+# index.hhp is a project file that can be read by Microsoft's HTML Help Workshop
+# on Windows. In the beginning of 2021 Microsoft took the original page, with
+# a.o. the download links, offline the HTML help workshop was already many years
+# in maintenance mode). You can download the HTML help workshop from the web
+# archives at Installation executable (see:
+# http://web.archive.org/web/20160201063255/http://download.microsoft.com/downlo
+# ad/0/A/9/0A939EF6-E31C-430F-A3DF-DFAE7960D564/htmlhelp.exe).
+#
+# The HTML Help Workshop contains a compiler that can convert all HTML output
+# generated by doxygen into a single compiled HTML file (.chm). Compiled HTML
+# files are now used as the Windows 98 help format, and will replace the old
+# Windows help format (.hlp) on all Windows platforms in the future. Compressed
+# HTML files also contain an index, a table of contents, and you can search for
+# words in the documentation. The HTML workshop also contains a viewer for
+# compressed HTML files.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_HTMLHELP      = NO
+
+# The CHM_FILE tag can be used to specify the file name of the resulting .chm
+# file. You can add a path in front of the file if the result should not be
+# written to the html output directory.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+CHM_FILE               =
+
+# The HHC_LOCATION tag can be used to specify the location (absolute path
+# including file name) of the HTML help compiler (hhc.exe). If non-empty,
+# doxygen will try to run the HTML help compiler on the generated index.hhp.
+# The file has to be specified with full path.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+HHC_LOCATION           =
+
+# The GENERATE_CHI flag controls if a separate .chi index file is generated
+# (YES) or that it should be included in the main .chm file (NO).
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+GENERATE_CHI           = NO
+
+# The CHM_INDEX_ENCODING is used to encode HtmlHelp index (hhk), content (hhc)
+# and project file content.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+CHM_INDEX_ENCODING     =
+
+# The BINARY_TOC flag controls whether a binary table of contents is generated
+# (YES) or a normal table of contents (NO) in the .chm file. Furthermore it
+# enables the Previous and Next buttons.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+BINARY_TOC             = NO
+
+# The TOC_EXPAND flag can be set to YES to add extra items for group members to
+# the table of contents of the HTML help documentation and to the tree view.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+TOC_EXPAND             = NO
+
+# If the GENERATE_QHP tag is set to YES and both QHP_NAMESPACE and
+# QHP_VIRTUAL_FOLDER are set, an additional index file will be generated that
+# can be used as input for Qt's qhelpgenerator to generate a Qt Compressed Help
+# (.qch) of the generated HTML documentation.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_QHP           = NO
+
+# If the QHG_LOCATION tag is specified, the QCH_FILE tag can be used to specify
+# the file name of the resulting .qch file. The path specified is relative to
+# the HTML output folder.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QCH_FILE               =
+
+# The QHP_NAMESPACE tag specifies the namespace to use when generating Qt Help
+# Project output. For more information please see Qt Help Project / Namespace
+# (see:
+# https://doc.qt.io/archives/qt-4.8/qthelpproject.html#namespace).
+# The default value is: org.doxygen.Project.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_NAMESPACE          = org.doxygen.Project
+
+# The QHP_VIRTUAL_FOLDER tag specifies the namespace to use when generating Qt
+# Help Project output. For more information please see Qt Help Project / Virtual
+# Folders (see:
+# https://doc.qt.io/archives/qt-4.8/qthelpproject.html#virtual-folders).
+# The default value is: doc.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_VIRTUAL_FOLDER     = doc
+
+# If the QHP_CUST_FILTER_NAME tag is set, it specifies the name of a custom
+# filter to add. For more information please see Qt Help Project / Custom
+# Filters (see:
+# https://doc.qt.io/archives/qt-4.8/qthelpproject.html#custom-filters).
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_CUST_FILTER_NAME   =
+
+# The QHP_CUST_FILTER_ATTRS tag specifies the list of the attributes of the
+# custom filter to add. For more information please see Qt Help Project / Custom
+# Filters (see:
+# https://doc.qt.io/archives/qt-4.8/qthelpproject.html#custom-filters).
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_CUST_FILTER_ATTRS  =
+
+# The QHP_SECT_FILTER_ATTRS tag specifies the list of the attributes this
+# project's filter section matches. Qt Help Project / Filter Attributes (see:
+# https://doc.qt.io/archives/qt-4.8/qthelpproject.html#filter-attributes).
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_SECT_FILTER_ATTRS  =
+
+# The QHG_LOCATION tag can be used to specify the location (absolute path
+# including file name) of Qt's qhelpgenerator. If non-empty doxygen will try to
+# run qhelpgenerator on the generated .qhp file.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHG_LOCATION           =
+
+# If the GENERATE_ECLIPSEHELP tag is set to YES, additional index files will be
+# generated, together with the HTML files, they form an Eclipse help plugin. To
+# install this plugin and make it available under the help contents menu in
+# Eclipse, the contents of the directory containing the HTML and XML files needs
+# to be copied into the plugins directory of eclipse. The name of the directory
+# within the plugins directory should be the same as the ECLIPSE_DOC_ID value.
+# After copying Eclipse needs to be restarted before the help appears.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_ECLIPSEHELP   = NO
+
+# A unique identifier for the Eclipse help plugin. When installing the plugin
+# the directory name containing the HTML and XML files should also have this
+# name. Each documentation set should have its own identifier.
+# The default value is: org.doxygen.Project.
+# This tag requires that the tag GENERATE_ECLIPSEHELP is set to YES.
+
+ECLIPSE_DOC_ID         = org.doxygen.Project
+
+# If you want full control over the layout of the generated HTML pages it might
+# be necessary to disable the index and replace it with your own. The
+# DISABLE_INDEX tag can be used to turn on/off the condensed index (tabs) at top
+# of each HTML page. A value of NO enables the index and the value YES disables
+# it. Since the tabs in the index contain the same information as the navigation
+# tree, you can set this option to YES if you also set GENERATE_TREEVIEW to YES.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+DISABLE_INDEX          = NO
+
+# The GENERATE_TREEVIEW tag is used to specify whether a tree-like index
+# structure should be generated to display hierarchical information. If the tag
+# value is set to YES, a side panel will be generated containing a tree-like
+# index structure (just like the one that is generated for HTML Help). For this
+# to work a browser that supports JavaScript, DHTML, CSS and frames is required
+# (i.e. any modern browser). Windows users are probably better off using the
+# HTML help feature. Via custom style sheets (see HTML_EXTRA_STYLESHEET) one can
+# further fine tune the look of the index (see "Fine-tuning the output"). As an
+# example, the default style sheet generated by doxygen has an example that
+# shows how to put an image at the root of the tree instead of the PROJECT_NAME.
+# Since the tree basically has the same information as the tab index, you could
+# consider setting DISABLE_INDEX to YES when enabling this option.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_TREEVIEW      = NO
+
+# When both GENERATE_TREEVIEW and DISABLE_INDEX are set to YES, then the
+# FULL_SIDEBAR option determines if the side bar is limited to only the treeview
+# area (value NO) or if it should extend to the full height of the window (value
+# YES). Setting this to YES gives a layout similar to
+# https://docs.readthedocs.io with more room for contents, but less room for the
+# project logo, title, and description. If either GENERATE_TREEVIEW or
+# DISABLE_INDEX is set to NO, this option has no effect.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+FULL_SIDEBAR           = NO
+
+# The ENUM_VALUES_PER_LINE tag can be used to set the number of enum values that
+# doxygen will group on one line in the generated HTML documentation.
+#
+# Note that a value of 0 will completely suppress the enum values from appearing
+# in the overview section.
+# Minimum value: 0, maximum value: 20, default value: 4.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+ENUM_VALUES_PER_LINE   = 4
+
+# If the treeview is enabled (see GENERATE_TREEVIEW) then this tag can be used
+# to set the initial width (in pixels) of the frame in which the tree is shown.
+# Minimum value: 0, maximum value: 1500, default value: 250.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+TREEVIEW_WIDTH         = 250
+
+# If the EXT_LINKS_IN_WINDOW option is set to YES, doxygen will open links to
+# external symbols imported via tag files in a separate window.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+EXT_LINKS_IN_WINDOW    = NO
+
+# If the OBFUSCATE_EMAILS tag is set to YES, doxygen will obfuscate email
+# addresses.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+OBFUSCATE_EMAILS       = YES
+
+# If the HTML_FORMULA_FORMAT option is set to svg, doxygen will use the pdf2svg
+# tool (see https://github.com/dawbarton/pdf2svg) or inkscape (see
+# https://inkscape.org) to generate formulas as SVG images instead of PNGs for
+# the HTML output. These images will generally look nicer at scaled resolutions.
+# Possible values are: png (the default) and svg (looks nicer but requires the
+# pdf2svg or inkscape tool).
+# The default value is: png.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_FORMULA_FORMAT    = png
+
+# Use this tag to change the font size of LaTeX formulas included as images in
+# the HTML documentation. When you change the font size after a successful
+# doxygen run you need to manually remove any form_*.png images from the HTML
+# output directory to force them to be regenerated.
+# Minimum value: 8, maximum value: 50, default value: 10.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+FORMULA_FONTSIZE       = 10
+
+# Use the FORMULA_TRANSPARENT tag to determine whether or not the images
+# generated for formulas are transparent PNGs. Transparent PNGs are not
+# supported properly for IE 6.0, but are supported on all modern browsers.
+#
+# Note that when changing this option you need to delete any form_*.png files in
+# the HTML output directory before the changes have effect.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+FORMULA_TRANSPARENT    = YES
+
+# The FORMULA_MACROFILE can contain LaTeX \newcommand and \renewcommand commands
+# to create new LaTeX commands to be used in formulas as building blocks. See
+# the section "Including formulas" for details.
+
+FORMULA_MACROFILE      =
+
+# Enable the USE_MATHJAX option to render LaTeX formulas using MathJax (see
+# https://www.mathjax.org) which uses client side JavaScript for the rendering
+# instead of using pre-rendered bitmaps. Use this if you do not have LaTeX
+# installed or if you want to formulas look prettier in the HTML output. When
+# enabled you may also need to install MathJax separately and configure the path
+# to it using the MATHJAX_RELPATH option.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+USE_MATHJAX            = NO
+
+# With MATHJAX_VERSION it is possible to specify the MathJax version to be used.
+# Note that the different versions of MathJax have different requirements with
+# regards to the different settings, so it is possible that also other MathJax
+# settings have to be changed when switching between the different MathJax
+# versions.
+# Possible values are: MathJax_2 and MathJax_3.
+# The default value is: MathJax_2.
+# This tag requires that the tag USE_MATHJAX is set to YES.
+
+MATHJAX_VERSION        = MathJax_2
+
+# When MathJax is enabled you can set the default output format to be used for
+# the MathJax output. For more details about the output format see MathJax
+# version 2 (see:
+# http://docs.mathjax.org/en/v2.7-latest/output.html) and MathJax version 3
+# (see:
+# http://docs.mathjax.org/en/latest/web/components/output.html).
+# Possible values are: HTML-CSS (which is slower, but has the best
+# compatibility. This is the name for Mathjax version 2, for MathJax version 3
+# this will be translated into chtml), NativeMML (i.e. MathML. Only supported
+# for NathJax 2. For MathJax version 3 chtml will be used instead.), chtml (This
+# is the name for Mathjax version 3, for MathJax version 2 this will be
+# translated into HTML-CSS) and SVG.
+# The default value is: HTML-CSS.
+# This tag requires that the tag USE_MATHJAX is set to YES.
+
+MATHJAX_FORMAT         = HTML-CSS
+
+# When MathJax is enabled you need to specify the location relative to the HTML
+# output directory using the MATHJAX_RELPATH option. The destination directory
+# should contain the MathJax.js script. For instance, if the mathjax directory
+# is located at the same level as the HTML output directory, then
+# MATHJAX_RELPATH should be ../mathjax. The default value points to the MathJax
+# Content Delivery Network so you can quickly see the result without installing
+# MathJax. However, it is strongly recommended to install a local copy of
+# MathJax from https://www.mathjax.org before deployment. The default value is:
+# - in case of MathJax version 2: https://cdn.jsdelivr.net/npm/mathjax@2
+# - in case of MathJax version 3: https://cdn.jsdelivr.net/npm/mathjax@3
+# This tag requires that the tag USE_MATHJAX is set to YES.
+
+MATHJAX_RELPATH        =
+
+# The MATHJAX_EXTENSIONS tag can be used to specify one or more MathJax
+# extension names that should be enabled during MathJax rendering. For example
+# for MathJax version 2 (see
+# https://docs.mathjax.org/en/v2.7-latest/tex.html#tex-and-latex-extensions):
+# MATHJAX_EXTENSIONS = TeX/AMSmath TeX/AMSsymbols
+# For example for MathJax version 3 (see
+# http://docs.mathjax.org/en/latest/input/tex/extensions/index.html):
+# MATHJAX_EXTENSIONS = ams
+# This tag requires that the tag USE_MATHJAX is set to YES.
+
+MATHJAX_EXTENSIONS     =
+
+# The MATHJAX_CODEFILE tag can be used to specify a file with javascript pieces
+# of code that will be used on startup of the MathJax code. See the MathJax site
+# (see:
+# http://docs.mathjax.org/en/v2.7-latest/output.html) for more details. For an
+# example see the documentation.
+# This tag requires that the tag USE_MATHJAX is set to YES.
+
+MATHJAX_CODEFILE       =
+
+# When the SEARCHENGINE tag is enabled doxygen will generate a search box for
+# the HTML output. The underlying search engine uses javascript and DHTML and
+# should work on any modern browser. Note that when using HTML help
+# (GENERATE_HTMLHELP), Qt help (GENERATE_QHP), or docsets (GENERATE_DOCSET)
+# there is already a search function so this one should typically be disabled.
+# For large projects the javascript based search engine can be slow, then
+# enabling SERVER_BASED_SEARCH may provide a better solution. It is possible to
+# search using the keyboard; to jump to the search box use <access key> + S
+# (what the <access key> is depends on the OS and browser, but it is typically
+# <CTRL>, <ALT>/<option>, or both). Inside the search box use the <cursor down
+# key> to jump into the search results window, the results can be navigated
+# using the <cursor keys>. Press <Enter> to select an item or <escape> to cancel
+# the search. The filter options can be selected when the cursor is inside the
+# search box by pressing <Shift>+<cursor down>. Also here use the <cursor keys>
+# to select a filter and <Enter> or <escape> to activate or cancel the filter
+# option.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+SEARCHENGINE           = YES
+
+# When the SERVER_BASED_SEARCH tag is enabled the search engine will be
+# implemented using a web server instead of a web client using JavaScript. There
+# are two flavors of web server based searching depending on the EXTERNAL_SEARCH
+# setting. When disabled, doxygen will generate a PHP script for searching and
+# an index file used by the script. When EXTERNAL_SEARCH is enabled the indexing
+# and searching needs to be provided by external tools. See the section
+# "External Indexing and Searching" for details.
+# The default value is: NO.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+SERVER_BASED_SEARCH    = NO
+
+# When EXTERNAL_SEARCH tag is enabled doxygen will no longer generate the PHP
+# script for searching. Instead the search results are written to an XML file
+# which needs to be processed by an external indexer. Doxygen will invoke an
+# external search engine pointed to by the SEARCHENGINE_URL option to obtain the
+# search results.
+#
+# Doxygen ships with an example indexer (doxyindexer) and search engine
+# (doxysearch.cgi) which are based on the open source search engine library
+# Xapian (see:
+# https://xapian.org/).
+#
+# See the section "External Indexing and Searching" for details.
+# The default value is: NO.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+EXTERNAL_SEARCH        = NO
+
+# The SEARCHENGINE_URL should point to a search engine hosted by a web server
+# which will return the search results when EXTERNAL_SEARCH is enabled.
+#
+# Doxygen ships with an example indexer (doxyindexer) and search engine
+# (doxysearch.cgi) which are based on the open source search engine library
+# Xapian (see:
+# https://xapian.org/). See the section "External Indexing and Searching" for
+# details.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+SEARCHENGINE_URL       =
+
+# When SERVER_BASED_SEARCH and EXTERNAL_SEARCH are both enabled the unindexed
+# search data is written to a file for indexing by an external tool. With the
+# SEARCHDATA_FILE tag the name of this file can be specified.
+# The default file is: searchdata.xml.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+SEARCHDATA_FILE        = searchdata.xml
+
+# When SERVER_BASED_SEARCH and EXTERNAL_SEARCH are both enabled the
+# EXTERNAL_SEARCH_ID tag can be used as an identifier for the project. This is
+# useful in combination with EXTRA_SEARCH_MAPPINGS to search through multiple
+# projects and redirect the results back to the right project.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+EXTERNAL_SEARCH_ID     =
+
+# The EXTRA_SEARCH_MAPPINGS tag can be used to enable searching through doxygen
+# projects other than the one defined by this configuration file, but that are
+# all added to the same external search index. Each project needs to have a
+# unique id set via EXTERNAL_SEARCH_ID. The search mapping then maps the id of
+# to a relative location where the documentation can be found. The format is:
+# EXTRA_SEARCH_MAPPINGS = tagname1=loc1 tagname2=loc2 ...
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+EXTRA_SEARCH_MAPPINGS  =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the LaTeX output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_LATEX tag is set to YES, doxygen will generate LaTeX output.
+# The default value is: YES.
+
+GENERATE_LATEX         = YES
+
+# The LATEX_OUTPUT tag is used to specify where the LaTeX docs will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it.
+# The default directory is: latex.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_OUTPUT           = latex
+
+# The LATEX_CMD_NAME tag can be used to specify the LaTeX command name to be
+# invoked.
+#
+# Note that when not enabling USE_PDFLATEX the default is latex when enabling
+# USE_PDFLATEX the default is pdflatex and when in the later case latex is
+# chosen this is overwritten by pdflatex. For specific output languages the
+# default can have been set differently, this depends on the implementation of
+# the output language.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_CMD_NAME         =
+
+# The MAKEINDEX_CMD_NAME tag can be used to specify the command name to generate
+# index for LaTeX.
+# Note: This tag is used in the Makefile / make.bat.
+# See also: LATEX_MAKEINDEX_CMD for the part in the generated output file
+# (.tex).
+# The default file is: makeindex.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+MAKEINDEX_CMD_NAME     = makeindex
+
+# The LATEX_MAKEINDEX_CMD tag can be used to specify the command name to
+# generate index for LaTeX. In case there is no backslash (\) as first character
+# it will be automatically added in the LaTeX code.
+# Note: This tag is used in the generated output file (.tex).
+# See also: MAKEINDEX_CMD_NAME for the part in the Makefile / make.bat.
+# The default value is: makeindex.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_MAKEINDEX_CMD    = makeindex
+
+# If the COMPACT_LATEX tag is set to YES, doxygen generates more compact LaTeX
+# documents. This may be useful for small projects and may help to save some
+# trees in general.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+COMPACT_LATEX          = NO
+
+# The PAPER_TYPE tag can be used to set the paper type that is used by the
+# printer.
+# Possible values are: a4 (210 x 297 mm), letter (8.5 x 11 inches), legal (8.5 x
+# 14 inches) and executive (7.25 x 10.5 inches).
+# The default value is: a4.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+PAPER_TYPE             = a4
+
+# The EXTRA_PACKAGES tag can be used to specify one or more LaTeX package names
+# that should be included in the LaTeX output. The package can be specified just
+# by its name or with the correct syntax as to be used with the LaTeX
+# \usepackage command. To get the times font for instance you can specify :
+# EXTRA_PACKAGES=times or EXTRA_PACKAGES={times}
+# To use the option intlimits with the amsmath package you can specify:
+# EXTRA_PACKAGES=[intlimits]{amsmath}
+# If left blank no extra packages will be included.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+EXTRA_PACKAGES         =
+
+# The LATEX_HEADER tag can be used to specify a user-defined LaTeX header for
+# the generated LaTeX document. The header should contain everything until the
+# first chapter. If it is left blank doxygen will generate a standard header. It
+# is highly recommended to start with a default header using
+# doxygen -w latex new_header.tex new_footer.tex new_stylesheet.sty
+# and then modify the file new_header.tex. See also section "Doxygen usage" for
+# information on how to generate the default header that doxygen normally uses.
+#
+# Note: Only use a user-defined header if you know what you are doing!
+# Note: The header is subject to change so you typically have to regenerate the
+# default header when upgrading to a newer version of doxygen. The following
+# commands have a special meaning inside the header (and footer): For a
+# description of the possible markers and block names see the documentation.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_HEADER           =
+
+# The LATEX_FOOTER tag can be used to specify a user-defined LaTeX footer for
+# the generated LaTeX document. The footer should contain everything after the
+# last chapter. If it is left blank doxygen will generate a standard footer. See
+# LATEX_HEADER for more information on how to generate a default footer and what
+# special commands can be used inside the footer. See also section "Doxygen
+# usage" for information on how to generate the default footer that doxygen
+# normally uses. Note: Only use a user-defined footer if you know what you are
+# doing!
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_FOOTER           =
+
+# The LATEX_EXTRA_STYLESHEET tag can be used to specify additional user-defined
+# LaTeX style sheets that are included after the standard style sheets created
+# by doxygen. Using this option one can overrule certain style aspects. Doxygen
+# will copy the style sheet files to the output directory.
+# Note: The order of the extra style sheet files is of importance (e.g. the last
+# style sheet in the list overrules the setting of the previous ones in the
+# list).
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_EXTRA_STYLESHEET =
+
+# The LATEX_EXTRA_FILES tag can be used to specify one or more extra images or
+# other source files which should be copied to the LATEX_OUTPUT output
+# directory. Note that the files will be copied as-is; there are no commands or
+# markers available.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_EXTRA_FILES      =
+
+# If the PDF_HYPERLINKS tag is set to YES, the LaTeX that is generated is
+# prepared for conversion to PDF (using ps2pdf or pdflatex). The PDF file will
+# contain links (just like the HTML output) instead of page references. This
+# makes the output suitable for online browsing using a PDF viewer.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+PDF_HYPERLINKS         = YES
+
+# If the USE_PDFLATEX tag is set to YES, doxygen will use the engine as
+# specified with LATEX_CMD_NAME to generate the PDF file directly from the LaTeX
+# files. Set this option to YES, to get a higher quality PDF documentation.
+#
+# See also section LATEX_CMD_NAME for selecting the engine.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+USE_PDFLATEX           = YES
+
+# If the LATEX_BATCHMODE tag is set to YES, doxygen will add the \batchmode
+# command to the generated LaTeX files. This will instruct LaTeX to keep running
+# if errors occur, instead of asking the user for help.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_BATCHMODE        = NO
+
+# If the LATEX_HIDE_INDICES tag is set to YES then doxygen will not include the
+# index chapters (such as File Index, Compound Index, etc.) in the output.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_HIDE_INDICES     = NO
+
+# The LATEX_BIB_STYLE tag can be used to specify the style to use for the
+# bibliography, e.g. plainnat, or ieeetr. See
+# https://en.wikipedia.org/wiki/BibTeX and \cite for more info.
+# The default value is: plain.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_BIB_STYLE        = plain
+
+# If the LATEX_TIMESTAMP tag is set to YES then the footer of each generated
+# page will contain the date and time when the page was generated. Setting this
+# to NO can help when comparing the output of multiple runs.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_TIMESTAMP        = NO
+
+# The LATEX_EMOJI_DIRECTORY tag is used to specify the (relative or absolute)
+# path from which the emoji images will be read. If a relative path is entered,
+# it will be relative to the LATEX_OUTPUT directory. If left blank the
+# LATEX_OUTPUT directory will be used.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_EMOJI_DIRECTORY  =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the RTF output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_RTF tag is set to YES, doxygen will generate RTF output. The
+# RTF output is optimized for Word 97 and may not look too pretty with other RTF
+# readers/editors.
+# The default value is: NO.
+
+GENERATE_RTF           = NO
+
+# The RTF_OUTPUT tag is used to specify where the RTF docs will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it.
+# The default directory is: rtf.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+RTF_OUTPUT             = rtf
+
+# If the COMPACT_RTF tag is set to YES, doxygen generates more compact RTF
+# documents. This may be useful for small projects and may help to save some
+# trees in general.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+COMPACT_RTF            = NO
+
+# If the RTF_HYPERLINKS tag is set to YES, the RTF that is generated will
+# contain hyperlink fields. The RTF file will contain links (just like the HTML
+# output) instead of page references. This makes the output suitable for online
+# browsing using Word or some other Word compatible readers that support those
+# fields.
+#
+# Note: WordPad (write) and others do not support links.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+RTF_HYPERLINKS         = NO
+
+# Load stylesheet definitions from file. Syntax is similar to doxygen's
+# configuration file, i.e. a series of assignments. You only have to provide
+# replacements, missing definitions are set to their default value.
+#
+# See also section "Doxygen usage" for information on how to generate the
+# default style sheet that doxygen normally uses.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+RTF_STYLESHEET_FILE    =
+
+# Set optional variables used in the generation of an RTF document. Syntax is
+# similar to doxygen's configuration file. A template extensions file can be
+# generated using doxygen -e rtf extensionFile.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+RTF_EXTENSIONS_FILE    =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the man page output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_MAN tag is set to YES, doxygen will generate man pages for
+# classes and files.
+# The default value is: NO.
+
+GENERATE_MAN           = NO
+
+# The MAN_OUTPUT tag is used to specify where the man pages will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it. A directory man3 will be created inside the directory specified by
+# MAN_OUTPUT.
+# The default directory is: man.
+# This tag requires that the tag GENERATE_MAN is set to YES.
+
+MAN_OUTPUT             = man
+
+# The MAN_EXTENSION tag determines the extension that is added to the generated
+# man pages. In case the manual section does not start with a number, the number
+# 3 is prepended. The dot (.) at the beginning of the MAN_EXTENSION tag is
+# optional.
+# The default value is: .3.
+# This tag requires that the tag GENERATE_MAN is set to YES.
+
+MAN_EXTENSION          = .3
+
+# The MAN_SUBDIR tag determines the name of the directory created within
+# MAN_OUTPUT in which the man pages are placed. If defaults to man followed by
+# MAN_EXTENSION with the initial . removed.
+# This tag requires that the tag GENERATE_MAN is set to YES.
+
+MAN_SUBDIR             =
+
+# If the MAN_LINKS tag is set to YES and doxygen generates man output, then it
+# will generate one additional man file for each entity documented in the real
+# man page(s). These additional files only source the real man page, but without
+# them the man command would be unable to find the correct page.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_MAN is set to YES.
+
+MAN_LINKS              = NO
+
+#---------------------------------------------------------------------------
+# Configuration options related to the XML output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_XML tag is set to YES, doxygen will generate an XML file that
+# captures the structure of the code including all documentation.
+# The default value is: NO.
+
+GENERATE_XML           = NO
+
+# The XML_OUTPUT tag is used to specify where the XML pages will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it.
+# The default directory is: xml.
+# This tag requires that the tag GENERATE_XML is set to YES.
+
+XML_OUTPUT             = xml
+
+# If the XML_PROGRAMLISTING tag is set to YES, doxygen will dump the program
+# listings (including syntax highlighting and cross-referencing information) to
+# the XML output. Note that enabling this will significantly increase the size
+# of the XML output.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_XML is set to YES.
+
+XML_PROGRAMLISTING     = YES
+
+# If the XML_NS_MEMB_FILE_SCOPE tag is set to YES, doxygen will include
+# namespace members in file scope as well, matching the HTML output.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_XML is set to YES.
+
+XML_NS_MEMB_FILE_SCOPE = NO
+
+#---------------------------------------------------------------------------
+# Configuration options related to the DOCBOOK output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_DOCBOOK tag is set to YES, doxygen will generate Docbook files
+# that can be used to generate PDF.
+# The default value is: NO.
+
+GENERATE_DOCBOOK       = NO
+
+# The DOCBOOK_OUTPUT tag is used to specify where the Docbook pages will be put.
+# If a relative path is entered the value of OUTPUT_DIRECTORY will be put in
+# front of it.
+# The default directory is: docbook.
+# This tag requires that the tag GENERATE_DOCBOOK is set to YES.
+
+DOCBOOK_OUTPUT         = docbook
+
+#---------------------------------------------------------------------------
+# Configuration options for the AutoGen Definitions output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_AUTOGEN_DEF tag is set to YES, doxygen will generate an
+# AutoGen Definitions (see http://autogen.sourceforge.net/) file that captures
+# the structure of the code including all documentation. Note that this feature
+# is still experimental and incomplete at the moment.
+# The default value is: NO.
+
+GENERATE_AUTOGEN_DEF   = NO
+
+#---------------------------------------------------------------------------
+# Configuration options related to the Perl module output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_PERLMOD tag is set to YES, doxygen will generate a Perl module
+# file that captures the structure of the code including all documentation.
+#
+# Note that this feature is still experimental and incomplete at the moment.
+# The default value is: NO.
+
+GENERATE_PERLMOD       = NO
+
+# If the PERLMOD_LATEX tag is set to YES, doxygen will generate the necessary
+# Makefile rules, Perl scripts and LaTeX code to be able to generate PDF and DVI
+# output from the Perl module output.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_PERLMOD is set to YES.
+
+PERLMOD_LATEX          = NO
+
+# If the PERLMOD_PRETTY tag is set to YES, the Perl module output will be nicely
+# formatted so it can be parsed by a human reader. This is useful if you want to
+# understand what is going on. On the other hand, if this tag is set to NO, the
+# size of the Perl module output will be much smaller and Perl will parse it
+# just the same.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_PERLMOD is set to YES.
+
+PERLMOD_PRETTY         = YES
+
+# The names of the make variables in the generated doxyrules.make file are
+# prefixed with the string contained in PERLMOD_MAKEVAR_PREFIX. This is useful
+# so different doxyrules.make files included by the same Makefile don't
+# overwrite each other's variables.
+# This tag requires that the tag GENERATE_PERLMOD is set to YES.
+
+PERLMOD_MAKEVAR_PREFIX =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the preprocessor
+#---------------------------------------------------------------------------
+
+# If the ENABLE_PREPROCESSING tag is set to YES, doxygen will evaluate all
+# C-preprocessor directives found in the sources and include files.
+# The default value is: YES.
+
+ENABLE_PREPROCESSING   = YES
+
+# If the MACRO_EXPANSION tag is set to YES, doxygen will expand all macro names
+# in the source code. If set to NO, only conditional compilation will be
+# performed. Macro expansion can be done in a controlled way by setting
+# EXPAND_ONLY_PREDEF to YES.
+# The default value is: NO.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+MACRO_EXPANSION        = NO
+
+# If the EXPAND_ONLY_PREDEF and MACRO_EXPANSION tags are both set to YES then
+# the macro expansion is limited to the macros specified with the PREDEFINED and
+# EXPAND_AS_DEFINED tags.
+# The default value is: NO.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+EXPAND_ONLY_PREDEF     = NO
+
+# If the SEARCH_INCLUDES tag is set to YES, the include files in the
+# INCLUDE_PATH will be searched if a #include is found.
+# The default value is: YES.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+SEARCH_INCLUDES        = YES
+
+# The INCLUDE_PATH tag can be used to specify one or more directories that
+# contain include files that are not input files but should be processed by the
+# preprocessor.
+# This tag requires that the tag SEARCH_INCLUDES is set to YES.
+
+INCLUDE_PATH           =
+
+# You can use the INCLUDE_FILE_PATTERNS tag to specify one or more wildcard
+# patterns (like *.h and *.hpp) to filter out the header-files in the
+# directories. If left blank, the patterns specified with FILE_PATTERNS will be
+# used.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+INCLUDE_FILE_PATTERNS  =
+
+# The PREDEFINED tag can be used to specify one or more macro names that are
+# defined before the preprocessor is started (similar to the -D option of e.g.
+# gcc). The argument of the tag is a list of macros of the form: name or
+# name=definition (no spaces). If the definition and the "=" are omitted, "=1"
+# is assumed. To prevent a macro definition from being undefined via #undef or
+# recursively expanded use the := operator instead of the = operator.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+PREDEFINED             =
+
+# If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
+# tag can be used to specify a list of macro names that should be expanded. The
+# macro definition that is found in the sources will be used. Use the PREDEFINED
+# tag if you want to use a different macro definition that overrules the
+# definition found in the source code.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+EXPAND_AS_DEFINED      =
+
+# If the SKIP_FUNCTION_MACROS tag is set to YES then doxygen's preprocessor will
+# remove all references to function-like macros that are alone on a line, have
+# an all uppercase name, and do not end with a semicolon. Such function macros
+# are typically used for boiler-plate code, and will confuse the parser if not
+# removed.
+# The default value is: YES.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+SKIP_FUNCTION_MACROS   = YES
+
+#---------------------------------------------------------------------------
+# Configuration options related to external references
+#---------------------------------------------------------------------------
+
+# The TAGFILES tag can be used to specify one or more tag files. For each tag
+# file the location of the external documentation should be added. The format of
+# a tag file without this location is as follows:
+# TAGFILES = file1 file2 ...
+# Adding location for the tag files is done as follows:
+# TAGFILES = file1=loc1 "file2 = loc2" ...
+# where loc1 and loc2 can be relative or absolute paths or URLs. See the
+# section "Linking to external documentation" for more information about the use
+# of tag files.
+# Note: Each tag file must have a unique name (where the name does NOT include
+# the path). If a tag file is not located in the directory in which doxygen is
+# run, you must also specify the path to the tagfile here.
+
+TAGFILES               =
+
+# When a file name is specified after GENERATE_TAGFILE, doxygen will create a
+# tag file that is based on the input files it reads. See section "Linking to
+# external documentation" for more information about the usage of tag files.
+
+GENERATE_TAGFILE       =
+
+# If the ALLEXTERNALS tag is set to YES, all external class will be listed in
+# the class index. If set to NO, only the inherited external classes will be
+# listed.
+# The default value is: NO.
+
+ALLEXTERNALS           = NO
+
+# If the EXTERNAL_GROUPS tag is set to YES, all external groups will be listed
+# in the modules index. If set to NO, only the current project's groups will be
+# listed.
+# The default value is: YES.
+
+EXTERNAL_GROUPS        = YES
+
+# If the EXTERNAL_PAGES tag is set to YES, all external pages will be listed in
+# the related pages index. If set to NO, only the current project's pages will
+# be listed.
+# The default value is: YES.
+
+EXTERNAL_PAGES         = YES
+
+#---------------------------------------------------------------------------
+# Configuration options related to the dot tool
+#---------------------------------------------------------------------------
+
+# You can include diagrams made with dia in doxygen documentation. Doxygen will
+# then run dia to produce the diagram and insert it in the documentation. The
+# DIA_PATH tag allows you to specify the directory where the dia binary resides.
+# If left empty dia is assumed to be found in the default search path.
+
+DIA_PATH               =
+
+# If set to YES the inheritance and collaboration graphs will hide inheritance
+# and usage relations if the target is undocumented or is not a class.
+# The default value is: YES.
+
+HIDE_UNDOC_RELATIONS   = YES
+
+# If you set the HAVE_DOT tag to YES then doxygen will assume the dot tool is
+# available from the path. This tool is part of Graphviz (see:
+# http://www.graphviz.org/), a graph visualization toolkit from AT&T and Lucent
+# Bell Labs. The other options in this section have no effect if this option is
+# set to NO
+# The default value is: NO.
+
+HAVE_DOT               = NO
+
+# The DOT_NUM_THREADS specifies the number of dot invocations doxygen is allowed
+# to run in parallel. When set to 0 doxygen will base this on the number of
+# processors available in the system. You can set it explicitly to a value
+# larger than 0 to get control over the balance between CPU load and processing
+# speed.
+# Minimum value: 0, maximum value: 32, default value: 0.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_NUM_THREADS        = 0
+
+# When you want a differently looking font in the dot files that doxygen
+# generates you can specify the font name using DOT_FONTNAME. You need to make
+# sure dot is able to find the font, which can be done by putting it in a
+# standard location or by setting the DOTFONTPATH environment variable or by
+# setting DOT_FONTPATH to the directory containing the font.
+# The default value is: Helvetica.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_FONTNAME           = Helvetica
+
+# The DOT_FONTSIZE tag can be used to set the size (in points) of the font of
+# dot graphs.
+# Minimum value: 4, maximum value: 24, default value: 10.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_FONTSIZE           = 10
+
+# By default doxygen will tell dot to use the default font as specified with
+# DOT_FONTNAME. If you specify a different font using DOT_FONTNAME you can set
+# the path where dot can find it using this tag.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_FONTPATH           =
+
+# If the CLASS_GRAPH tag is set to YES (or GRAPH) then doxygen will generate a
+# graph for each documented class showing the direct and indirect inheritance
+# relations. In case HAVE_DOT is set as well dot will be used to draw the graph,
+# otherwise the built-in generator will be used. If the CLASS_GRAPH tag is set
+# to TEXT the direct and indirect inheritance relations will be shown as texts /
+# links.
+# Possible values are: NO, YES, TEXT and GRAPH.
+# The default value is: YES.
+
+CLASS_GRAPH            = YES
+
+# If the COLLABORATION_GRAPH tag is set to YES then doxygen will generate a
+# graph for each documented class showing the direct and indirect implementation
+# dependencies (inheritance, containment, and class references variables) of the
+# class with other documented classes.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+COLLABORATION_GRAPH    = YES
+
+# If the GROUP_GRAPHS tag is set to YES then doxygen will generate a graph for
+# groups, showing the direct groups dependencies.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+GROUP_GRAPHS           = YES
+
+# If the UML_LOOK tag is set to YES, doxygen will generate inheritance and
+# collaboration diagrams in a style similar to the OMG's Unified Modeling
+# Language.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+UML_LOOK               = NO
+
+# If the UML_LOOK tag is enabled, the fields and methods are shown inside the
+# class node. If there are many fields or methods and many nodes the graph may
+# become too big to be useful. The UML_LIMIT_NUM_FIELDS threshold limits the
+# number of items for each type to make the size more manageable. Set this to 0
+# for no limit. Note that the threshold may be exceeded by 50% before the limit
+# is enforced. So when you set the threshold to 10, up to 15 fields may appear,
+# but if the number exceeds 15, the total amount of fields shown is limited to
+# 10.
+# Minimum value: 0, maximum value: 100, default value: 10.
+# This tag requires that the tag UML_LOOK is set to YES.
+
+UML_LIMIT_NUM_FIELDS   = 10
+
+# If the DOT_UML_DETAILS tag is set to NO, doxygen will show attributes and
+# methods without types and arguments in the UML graphs. If the DOT_UML_DETAILS
+# tag is set to YES, doxygen will add type and arguments for attributes and
+# methods in the UML graphs. If the DOT_UML_DETAILS tag is set to NONE, doxygen
+# will not generate fields with class member information in the UML graphs. The
+# class diagrams will look similar to the default class diagrams but using UML
+# notation for the relationships.
+# Possible values are: NO, YES and NONE.
+# The default value is: NO.
+# This tag requires that the tag UML_LOOK is set to YES.
+
+DOT_UML_DETAILS        = NO
+
+# The DOT_WRAP_THRESHOLD tag can be used to set the maximum number of characters
+# to display on a single line. If the actual line length exceeds this threshold
+# significantly it will wrapped across multiple lines. Some heuristics are apply
+# to avoid ugly line breaks.
+# Minimum value: 0, maximum value: 1000, default value: 17.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_WRAP_THRESHOLD     = 17
+
+# If the TEMPLATE_RELATIONS tag is set to YES then the inheritance and
+# collaboration graphs will show the relations between templates and their
+# instances.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+TEMPLATE_RELATIONS     = NO
+
+# If the INCLUDE_GRAPH, ENABLE_PREPROCESSING and SEARCH_INCLUDES tags are set to
+# YES then doxygen will generate a graph for each documented file showing the
+# direct and indirect include dependencies of the file with other documented
+# files.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+INCLUDE_GRAPH          = YES
+
+# If the INCLUDED_BY_GRAPH, ENABLE_PREPROCESSING and SEARCH_INCLUDES tags are
+# set to YES then doxygen will generate a graph for each documented file showing
+# the direct and indirect include dependencies of the file with other documented
+# files.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+INCLUDED_BY_GRAPH      = YES
+
+# If the CALL_GRAPH tag is set to YES then doxygen will generate a call
+# dependency graph for every global function or class method.
+#
+# Note that enabling this option will significantly increase the time of a run.
+# So in most cases it will be better to enable call graphs for selected
+# functions only using the \callgraph command. Disabling a call graph can be
+# accomplished by means of the command \hidecallgraph.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+CALL_GRAPH             = NO
+
+# If the CALLER_GRAPH tag is set to YES then doxygen will generate a caller
+# dependency graph for every global function or class method.
+#
+# Note that enabling this option will significantly increase the time of a run.
+# So in most cases it will be better to enable caller graphs for selected
+# functions only using the \callergraph command. Disabling a caller graph can be
+# accomplished by means of the command \hidecallergraph.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+CALLER_GRAPH           = NO
+
+# If the GRAPHICAL_HIERARCHY tag is set to YES then doxygen will graphical
+# hierarchy of all classes instead of a textual one.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+GRAPHICAL_HIERARCHY    = YES
+
+# If the DIRECTORY_GRAPH tag is set to YES then doxygen will show the
+# dependencies a directory has on other directories in a graphical way. The
+# dependency relations are determined by the #include relations between the
+# files in the directories.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DIRECTORY_GRAPH        = YES
+
+# The DIR_GRAPH_MAX_DEPTH tag can be used to limit the maximum number of levels
+# of child directories generated in directory dependency graphs by dot.
+# Minimum value: 1, maximum value: 25, default value: 1.
+# This tag requires that the tag DIRECTORY_GRAPH is set to YES.
+
+DIR_GRAPH_MAX_DEPTH    = 1
+
+# The DOT_IMAGE_FORMAT tag can be used to set the image format of the images
+# generated by dot. For an explanation of the image formats see the section
+# output formats in the documentation of the dot tool (Graphviz (see:
+# http://www.graphviz.org/)).
+# Note: If you choose svg you need to set HTML_FILE_EXTENSION to xhtml in order
+# to make the SVG files visible in IE 9+ (other browsers do not have this
+# requirement).
+# Possible values are: png, jpg, gif, svg, png:gd, png:gd:gd, png:cairo,
+# png:cairo:gd, png:cairo:cairo, png:cairo:gdiplus, png:gdiplus and
+# png:gdiplus:gdiplus.
+# The default value is: png.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_IMAGE_FORMAT       = png
+
+# If DOT_IMAGE_FORMAT is set to svg, then this option can be set to YES to
+# enable generation of interactive SVG images that allow zooming and panning.
+#
+# Note that this requires a modern browser other than Internet Explorer. Tested
+# and working are Firefox, Chrome, Safari, and Opera.
+# Note: For IE 9+ you need to set HTML_FILE_EXTENSION to xhtml in order to make
+# the SVG files visible. Older versions of IE do not have SVG support.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+INTERACTIVE_SVG        = NO
+
+# The DOT_PATH tag can be used to specify the path where the dot tool can be
+# found. If left blank, it is assumed the dot tool can be found in the path.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_PATH               =
+
+# The DOTFILE_DIRS tag can be used to specify one or more directories that
+# contain dot files that are included in the documentation (see the \dotfile
+# command).
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOTFILE_DIRS           =
+
+# The MSCFILE_DIRS tag can be used to specify one or more directories that
+# contain msc files that are included in the documentation (see the \mscfile
+# command).
+
+MSCFILE_DIRS           =
+
+# The DIAFILE_DIRS tag can be used to specify one or more directories that
+# contain dia files that are included in the documentation (see the \diafile
+# command).
+
+DIAFILE_DIRS           =
+
+# When using plantuml, the PLANTUML_JAR_PATH tag should be used to specify the
+# path where java can find the plantuml.jar file or to the filename of jar file
+# to be used. If left blank, it is assumed PlantUML is not used or called during
+# a preprocessing step. Doxygen will generate a warning when it encounters a
+# \startuml command in this case and will not generate output for the diagram.
+
+PLANTUML_JAR_PATH      =
+
+# When using plantuml, the PLANTUML_CFG_FILE tag can be used to specify a
+# configuration file for plantuml.
+
+PLANTUML_CFG_FILE      =
+
+# When using plantuml, the specified paths are searched for files specified by
+# the !include statement in a plantuml block.
+
+PLANTUML_INCLUDE_PATH  =
+
+# The DOT_GRAPH_MAX_NODES tag can be used to set the maximum number of nodes
+# that will be shown in the graph. If the number of nodes in a graph becomes
+# larger than this value, doxygen will truncate the graph, which is visualized
+# by representing a node as a red box. Note that doxygen if the number of direct
+# children of the root node in a graph is already larger than
+# DOT_GRAPH_MAX_NODES then the graph will not be shown at all. Also note that
+# the size of a graph can be further restricted by MAX_DOT_GRAPH_DEPTH.
+# Minimum value: 0, maximum value: 10000, default value: 50.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_GRAPH_MAX_NODES    = 50
+
+# The MAX_DOT_GRAPH_DEPTH tag can be used to set the maximum depth of the graphs
+# generated by dot. A depth value of 3 means that only nodes reachable from the
+# root by following a path via at most 3 edges will be shown. Nodes that lay
+# further from the root node will be omitted. Note that setting this option to 1
+# or 2 may greatly reduce the computation time needed for large code bases. Also
+# note that the size of a graph can be further restricted by
+# DOT_GRAPH_MAX_NODES. Using a depth of 0 means no depth restriction.
+# Minimum value: 0, maximum value: 1000, default value: 0.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+MAX_DOT_GRAPH_DEPTH    = 0
+
+# Set the DOT_TRANSPARENT tag to YES to generate images with a transparent
+# background. This is disabled by default, because dot on Windows does not seem
+# to support this out of the box.
+#
+# Warning: Depending on the platform used, enabling this option may lead to
+# badly anti-aliased labels on the edges of a graph (i.e. they become hard to
+# read).
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_TRANSPARENT        = NO
+
+# Set the DOT_MULTI_TARGETS tag to YES to allow dot to generate multiple output
+# files in one run (i.e. multiple -o and -T options on the command line). This
+# makes dot run faster, but since only newer versions of dot (>1.8.10) support
+# this, this feature is disabled by default.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_MULTI_TARGETS      = NO
+
+# If the GENERATE_LEGEND tag is set to YES doxygen will generate a legend page
+# explaining the meaning of the various boxes and arrows in the dot generated
+# graphs.
+# Note: This tag requires that UML_LOOK isn't set, i.e. the doxygen internal
+# graphical representation for inheritance and collaboration diagrams is used.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+GENERATE_LEGEND        = YES
+
+# If the DOT_CLEANUP tag is set to YES, doxygen will remove the intermediate
+# files that are used to generate the various graphs.
+#
+# Note: This setting is not only used for dot files but also for msc temporary
+# files.
+# The default value is: YES.
+
+DOT_CLEANUP            = YES
diff --git a/LICENSE.txt b/LICENSE.txt
new file mode 100644
index 0000000..b09cd78
--- /dev/null
+++ b/LICENSE.txt
@@ -0,0 +1,201 @@
+Apache License
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+
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+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/README.markdown b/README.markdown
new file mode 100644
index 0000000..6785d0d
--- /dev/null
+++ b/README.markdown
@@ -0,0 +1,12 @@
+CandyGear
+=========
+
+CandyGear is a 2D game engine for mruby, and it is built on top of SDL. It aims to be very flexible and make the development of small games straightforward.
+
+Installation
+------------
+
+CandyGear uses the libraries libSDL2, SDL2\_image, SDL2\_mixer, libSDL2\_ttf, and yaml-cpp, so before installing CandyGear into a machine, ensure that development libraries for SDL are installed.
+CandyGear is compiled with Ruby Rake; also ensure it is installed.
+To compile the code, run `rake` at the root directory; it will generate the binary engine.
+To install the core, run `rake install`.
diff --git a/Rakefile b/Rakefile
new file mode 100644
index 0000000..48ecab3
--- /dev/null
+++ b/Rakefile
@@ -0,0 +1,72 @@
+# Copyright 2022 Frederico de Oliveira Linhares
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+require 'rake/clean'
+require 'rake/loaders/makefile'
+
+OBJ = 'candy_gear'
+
+DATA_DIR = '/usr/local/share/candy_gear'
+
+C_FILES = FileList[
+  'src/*.c'
+]
+C_OBJS = C_FILES.ext('.o')
+
+CPP_FILES = FileList[
+  'src/*.cpp'
+]
+CPP_OBJS = CPP_FILES.ext('.o')
+
+OBJ_FILES = C_OBJS + CPP_OBJS
+
+RB_LIBS = FileList[
+  'lib/*.rb'
+]
+
+LIBRARIES = [
+    'SDL2',
+    'SDL2_image',
+    'SDL2_mixer',
+    'SDL2_ttf',
+    'm',
+    'mruby',
+    'yaml-cpp'
+]
+
+task :doc do
+  `doxygen Doxyfile`
+end
+
+rule '.o' => ['.c'] do |t|
+  `gcc -c -std=c99 #{t.source} -o #{t.name}`
+end
+
+rule '.o' => ['.cpp'] do |t|
+  `g++ -c -std=c++17 #{t.source} -o #{t.name}`
+end
+
+task build: OBJ_FILES do
+  libs = LIBRARIES.inject('') {_1 + "-l#{_2} "}
+
+  `g++ -o #{OBJ} #{OBJ_FILES} #{libs}`
+end
+
+task :install do
+  `install #{OBJ} /usr/local/bin`
+  `install -d #{DATA_DIR}/lib`
+  RB_LIBS.each {`install #{_1} #{DATA_DIR}/lib`}
+end
+
+task default: %[build]
diff --git a/lib/menu.rb b/lib/menu.rb
new file mode 100644
index 0000000..a3f1533
--- /dev/null
+++ b/lib/menu.rb
@@ -0,0 +1,202 @@
+# Copyright 2021 Frederico de Oliveira Linhares
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+module CandyGear
+  class Menu
+    class BorderlessView
+      attr_reader(:texture, :font, :text_color, :bg_color, :sprites);
+
+      def initialize(
+            texture, font, text_color, bg_color, sprite_width, sprite_height)
+        @texture = texture;
+        @font = font;
+        @text_color = text_color;
+        @bg_color = bg_color;
+        @sprite_width = sprite_width;
+        @sprite_height = sprite_height;
+
+        @sprites = {};
+        @sprites[:arrow_select] = Sprite.new(
+          @texture, 1 * @sprite_width, 1 * @sprite_height,
+          @sprite_width, @sprite_height);
+      end
+
+      def draw(x, y, width, height)
+        # Nothing.
+      end
+
+      def border_width() = 0;
+      def border_height() = 0;
+    end
+
+    class BorderedView
+      attr_reader(
+        :texture, :font, :text_color, :bg_color, :sprites, :border_width,
+        :border_height);
+
+      def initialize(
+            texture, font, text_color, bg_color, sprite_width, sprite_height)
+        @texture = texture;
+        @font = font;
+        @text_color = text_color;
+        @bg_color = bg_color;
+        @border_width = sprite_width;
+        @border_height = sprite_height;
+
+        @sprites = {};
+        @sprites[:arrow_select] = Sprite.new(
+          @texture, 1 * @border_width, 1 * @border_height,
+          @border_width, @border_height);
+        @sprites[:box_top_left] = Sprite.new(
+          @texture, 0, 0, @border_width, @border_height);
+        @sprites[:box_top] = Sprite.new(
+          @texture, 1 * @border_width, 0,
+          @border_width, @border_height);
+        @sprites[:box_top_right] = Sprite.new(
+          @texture, 2 * @border_height, 0,
+          @border_width, @border_height);
+        @sprites[:box_left] = Sprite.new(
+          @texture, 0, 1 * @border_height,
+          @border_width, @border_height);
+        @sprites[:box_right] = Sprite.new(
+          @texture, 2 * @border_width, 1 * @border_height,
+          @border_width, @border_height);
+        @sprites[:box_bottom_left] = Sprite.new(
+          @texture, 0, 2 * @border_height,
+          @border_width, @border_height);
+        @sprites[:box_bottom] = Sprite.new(
+          @texture, 1 * @border_width, 2 * @border_height,
+          @border_width, @border_height);
+        @sprites[:box_bottom_right] = Sprite.new(
+          @texture, 2 * @border_width, 2 * @border_height,
+          @border_width, @border_height);
+      end
+
+      def draw(x, y, width, height)
+        num_horizontal_sprites = width / @border_width + 1;
+        num_horizontal_sprites += 1 if width % @border_width > 0;
+        num_vertical_sprites = height / @border_height;
+        num_vertical_sprites += 1 if height % @border_height > 0;
+        background = Rect.new(
+          x, y,
+          (num_horizontal_sprites + 2) * @border_width,
+          (num_vertical_sprites + 2) * @border_height);
+
+        Graphic.set_color(@bg_color);
+        background.draw_fill();
+
+        # Draw the corners.
+        @sprites[:box_top_left].draw_xy(x, y);
+        @sprites[:box_top_right].draw_xy(
+          @border_width * (num_horizontal_sprites + 1) + x, y);
+        @sprites[:box_bottom_left].draw_xy(
+          x, @border_height * (num_vertical_sprites + 1) + y);
+        @sprites[:box_bottom_right].draw_xy(
+          @border_width * (num_horizontal_sprites + 1) + x,
+          @border_height * (num_vertical_sprites + 1) + y);
+
+        # Draw the edges.
+        num_horizontal_sprites.times do |i|
+          # Top
+          @sprites[:box_top].draw_xy(@border_width * (i + 1) + x, y);
+          # Bottom
+          @sprites[:box_bottom].draw_xy(
+            @border_width * (i + 1) + x,
+            @border_height * (num_vertical_sprites + 1) + y);
+        end
+        num_vertical_sprites.times do |i|
+          # Left
+          @sprites[:box_left].draw_xy(x, @border_height * (i + 1) + y);
+          # Right
+          @sprites[:box_right].draw_xy(
+            @border_width * (num_horizontal_sprites + 1) + x,
+            @border_height * (i + 1) + y);
+        end
+      end
+    end
+
+    class Option
+      attr_reader(:action, :text);
+
+      def initialize(text, action);
+        @text = text;
+        @action = action;
+      end
+    end
+
+    attr_reader(:width, :height);
+
+    def initialize(view, pos_x, pos_y, options)
+      @view = view;
+
+      @pos_x = pos_x;
+      @pos_y = pos_y;
+
+      @options = options.map do |opt|
+        Option.new(
+          Texture.from_text(
+            opt[:text], view.font, view.text_color, view.bg_color),
+          opt[:action]);
+      end
+      @current_option = 0;
+      @option_max_width = 0;
+      @option_max_height = 0;
+
+      @options.each do |i|
+        if @option_max_width < i.text.width then
+          @option_max_width = i.text.width;
+        end
+        if @option_max_height < i.text.height then
+          @option_max_height = i.text.height;
+        end
+      end
+
+      @width = @option_max_width;
+      @height = @option_max_height * @options.size;
+    end
+
+    def next_opt()
+      @current_option += 1;
+      @current_option = 0 if @current_option >= @options.size();
+    end
+
+    def pred_opt()
+      if @current_option <= 0 then
+        @current_option = @options.size - 1;
+      else
+        @current_option -= 1;
+      end
+    end
+
+    def activate()
+      @options[@current_option].action.call();
+    end
+
+    def draw()
+      @view.draw(@pos_x, @pos_y, @width, @height);
+
+      @options.each_with_index do |opt, i|
+        opt.text.draw_xy(
+          @pos_x + @view.border_width + @view.sprites[:arrow_select].width,
+          @pos_y + @view.border_height +
+          @option_max_height * i);
+      end
+
+      @view.sprites[:arrow_select].draw_xy(
+          @pos_x + @view.border_width,
+          @pos_y + @view.border_height +
+          @option_max_height * @current_option);
+    end
+  end
+end
diff --git a/src/candy_gear.cpp b/src/candy_gear.cpp
new file mode 100644
index 0000000..484ce6a
--- /dev/null
+++ b/src/candy_gear.cpp
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "candy_gear.h"
+
+#include <mruby/array.h>
+#include <mruby/hash.h>
+#include <mruby/string.h>
+
+#include <yaml-cpp/yaml.h>
+
+static mrb_value
+parse_node(mrb_state *mrb, const YAML::Node &node)
+{
+  mrb_value value;
+  std::string scalar;
+
+  switch(node.Type())
+  {
+  case YAML::NodeType::Null:
+    return mrb_nil_value();
+
+  case YAML::NodeType::Scalar:
+    scalar = node.as<std::string>();
+    return mrb_str_new(mrb, scalar.data(), scalar.size());
+
+  case YAML::NodeType::Sequence:
+    value = mrb_ary_new_capa(mrb, node.size());
+    for (YAML::const_iterator it = node.begin(); it != node.end(); it++)
+      mrb_ary_push(mrb, value, parse_node(mrb, *it));
+    return value;
+
+  case YAML::NodeType::Map:
+    value = mrb_hash_new_capa(mrb, node.size());
+    for(YAML::const_iterator it = node.begin(); it != node.end(); it++)
+      mrb_hash_set(
+	mrb, value, parse_node(mrb, it->first), parse_node(mrb, it->second));
+    return value;
+
+  case YAML::NodeType::Undefined:
+  default:
+    return mrb_nil_value();
+  }
+}
+
+static mrb_value
+cg_mCandyGear_load_yaml(mrb_state *mrb, mrb_value self)
+{
+  const char *file_path;
+
+  mrb_get_args(mrb, "z", &file_path);
+
+  YAML::Node root = YAML::LoadFile(file_path);
+
+  return parse_node(mrb, root);
+}
+
+static mrb_value
+cg_mCandyGear_quit(mrb_state *mrb, mrb_value self)
+{
+  cg_core.quit_game = SDL_TRUE;
+
+  return self;
+}
+
+void
+cg_candy_gear_init(mrb_state *mrb)
+{
+  struct RClass *cg_m;
+
+  cg_m = mrb_module_get(mrb, "CandyGear");
+  mrb_define_class_method(
+    mrb, cg_m, "load_yaml", cg_mCandyGear_load_yaml, MRB_ARGS_REQ(1));
+  mrb_define_class_method(
+    mrb, cg_m, "quit", cg_mCandyGear_quit, MRB_ARGS_NONE());
+}
diff --git a/src/candy_gear.h b/src/candy_gear.h
new file mode 100644
index 0000000..aca4740
--- /dev/null
+++ b/src/candy_gear.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_GRAPHIC_H
+#define CANDY_GEAR_CANDY_GEAR_H 1
+
+#include "core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void
+cg_candy_gear_init(mrb_state *mrb);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_CANDY_GEAR_H */
diff --git a/src/color.c b/src/color.c
new file mode 100644
index 0000000..0ab9392
--- /dev/null
+++ b/src/color.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "color.h"
+
+void
+cg_free_color(mrb_state *mrb, void* obj)
+{
+  struct cg_color *ptr = obj;
+
+  mrb_free(mrb, ptr);
+}
+
+const struct mrb_data_type cg_color_type = { "CG_Color", cg_free_color };
+
+static mrb_value
+cg_cColor_initialize(mrb_state *mrb, mrb_value self)
+{
+  mrb_int red, green, blue, alpha;
+  struct cg_color *ptr;
+
+  alpha = 0xff;
+  mrb_get_args(mrb, "iii|i", &red, &green, &blue, &alpha);
+  ptr = (struct cg_color *)DATA_PTR(self);
+  if(ptr) mrb_free(mrb, ptr);
+  ptr = (struct cg_color *)mrb_malloc(mrb, sizeof(struct cg_color));
+
+  ptr->data.r = red;
+  ptr->data.g = green;
+  ptr->data.b = blue;
+  ptr->data.a = alpha;
+
+  mrb_data_init(self, ptr, &cg_color_type);
+  return self;
+}
+
+void
+cg_color_init(mrb_state *mrb)
+{
+  struct RClass *cg_m, *cg_cColor;
+
+  cg_m = mrb_module_get(mrb, "CandyGear");
+  cg_cColor = mrb_define_class_under(mrb, cg_m, "Color", mrb->object_class);
+  MRB_SET_INSTANCE_TT(cg_cColor, MRB_TT_DATA);
+  mrb_define_method(
+    mrb, cg_cColor, "initialize", cg_cColor_initialize,
+    MRB_ARGS_REQ(3) | MRB_ARGS_OPT(1));
+}
diff --git a/src/color.h b/src/color.h
new file mode 100644
index 0000000..ee1b3ed
--- /dev/null
+++ b/src/color.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_COLOR_H
+#define CANDY_GEAR_COLOR_H 1
+
+#include "core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct cg_color
+{
+  SDL_Color data;
+};
+
+extern const struct mrb_data_type cg_color_type;
+
+void
+cg_color_init(mrb_state *mrb);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_COLOR_H */
diff --git a/src/core.cpp b/src/core.cpp
new file mode 100644
index 0000000..12e5b01
--- /dev/null
+++ b/src/core.cpp
@@ -0,0 +1,292 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "core.h"
+
+#include <yaml-cpp/yaml.h>
+
+/*
+  Stretches the image to fill the screen vertically, horizontally, or both;
+  without changing the game aspect ratio.
+ */
+void
+cg_Engine_calculate_full_scale()
+{
+  double screen_ratio, game_ratio, scale;
+
+  screen_ratio =
+      (double)cg_core.screen_width/(double)cg_core.screen_height;
+  game_ratio = (double)cg_core.game_width/(double)cg_core.game_height;
+
+  // If screen is proportionally taller than game.
+  if(screen_ratio < game_ratio)
+  {
+    scale = (double)cg_core.screen_width/(double)cg_core.game_width;
+
+    cg_core.screen_rect.w = cg_core.game_width * scale;
+    cg_core.screen_rect.h = cg_core.game_height * scale;
+    cg_core.screen_rect.x = 0;
+    cg_core.screen_rect.y = cg_core.screen_height/2 -
+                             cg_core.screen_rect.h/2;
+  }
+  // If screen is proportionally wider than game.
+  else if(screen_ratio > game_ratio)
+  {
+    scale = (double)cg_core.screen_height/(double)cg_core.game_height;
+
+    cg_core.screen_rect.w = cg_core.game_width * scale;
+    cg_core.screen_rect.h = cg_core.game_height * scale;
+    cg_core.screen_rect.x = cg_core.screen_width/2 -
+                             cg_core.screen_rect.w/2;
+    cg_core.screen_rect.y = 0;
+  }
+  // If they have the same aspect ratio.
+  else
+  {
+    cg_core.screen_rect.x = 0;
+    cg_core.screen_rect.y = 0;
+    cg_core.screen_rect.w = cg_core.screen_width;
+    cg_core.screen_rect.h = cg_core.screen_height;
+  }
+}
+
+static SDL_bool
+load_variables(void *obj, LoaderStack *ls)
+{
+  YAML::Node root = YAML::LoadFile(cg_core.config_file);
+
+  std::string game_name = root["name"].as<std::string>().c_str();
+  cg_core.game_name = new char[game_name.size() + 1];
+  strcpy(cg_core.game_name, game_name.c_str());
+
+  // Based on NES.
+  cg_core.game_width = root["game"]["width"].as<int>();
+  cg_core.game_height = root["game"]["height"].as<int>();
+  cg_core.screen_width = root["screen"]["width"].as<int>();
+  cg_core.screen_height = root["screen"]["height"].as<int>();
+
+  cg_core.fps = 30;
+  cg_core.max_frame_duration_ms = 1000 / cg_core.fps;
+
+  return SDL_TRUE;
+}
+
+static void
+unload_variables(void *obj, LoaderStack *ls)
+{
+  delete[] cg_core.game_name;
+}
+
+static SDL_bool
+load_sdl(void *obj, LoaderStack *ls)
+{
+  if(SDL_Init(SDL_INIT_EVERYTHING) < 0)
+  {
+    const char* base_error = "SDL could not initialize! SDL Error → ";
+    LoaderStack_set_error(ls, base_error, SDL_GetError());
+    return SDL_FALSE;
+  }
+
+  return SDL_TRUE;
+}
+
+static void
+unload_sdl(void *obj, LoaderStack *ls)
+{
+  SDL_Quit();
+}
+
+static SDL_bool
+load_sdl_image(void *obj, LoaderStack *ls)
+{
+  int flags = IMG_INIT_JPG|IMG_INIT_PNG|IMG_INIT_TIF;
+  if(!(IMG_Init(flags) & flags))
+  {
+    const char* base_error = "Could not initialize SDL image → ";
+    LoaderStack_set_error(ls, base_error, IMG_GetError());
+    return SDL_FALSE;
+  }
+
+  return SDL_TRUE;
+}
+
+static void
+unload_sdl_image(void *obj, LoaderStack *ls)
+{
+  IMG_Quit();
+}
+
+static SDL_bool
+load_sdl_mixer(void *obj, LoaderStack *ls)
+{
+  int flags = MIX_INIT_OGG|MIX_INIT_MOD;
+  int initted = Mix_Init(flags);
+  if(initted&flags != flags)
+  {
+    const char* base_error = "Could not initialize SDL mixer → ";
+    LoaderStack_set_error(ls, base_error, Mix_GetError());
+    return SDL_FALSE;
+  }
+
+  return SDL_TRUE;
+}
+
+static void
+unload_sdl_mixer(void *obj, LoaderStack *ls)
+{
+  while(Mix_Init(0)) Mix_Quit();
+}
+
+static SDL_bool
+load_sdl_open_audio(void *obj, LoaderStack *ls)
+{
+  if(Mix_OpenAudio(22050, MIX_DEFAULT_FORMAT, 2, 1024) == -1)
+  {
+    const char* base_error = "Could not open SDL mixer audio → ";
+    LoaderStack_set_error(ls, base_error, Mix_GetError());
+    return SDL_FALSE;
+  }
+
+  return SDL_TRUE;
+}
+
+static void
+unload_sdl_open_audio(void *obj, LoaderStack *ls)
+{
+  Mix_CloseAudio();
+}
+
+static SDL_bool
+load_sdl_ttf(void *obj, LoaderStack *ls)
+{
+  if(TTF_Init()==-1)
+  {
+    const char* base_error = "Could not initialize SDL ttf → ";
+    LoaderStack_set_error(ls, base_error, TTF_GetError());
+    return SDL_FALSE;
+  }
+
+  return SDL_TRUE;
+}
+
+static void
+unload_sdl_ttf(void *obj, LoaderStack *ls)
+{
+  TTF_Quit();
+}
+
+static SDL_bool
+load_window(void *obj, LoaderStack *ls)
+{
+  cg_core.window = NULL;
+  cg_core.window = SDL_CreateWindow(
+    cg_core.game_name, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
+    cg_core.screen_width, cg_core.screen_height, SDL_WINDOW_SHOWN);
+  if(cg_core.window == NULL)
+  {
+    const char* base_error = "Window could not be created! SDL_Error → ";
+    LoaderStack_set_error(ls, base_error, SDL_GetError());
+    return SDL_FALSE;
+  }
+
+  return SDL_TRUE;
+}
+
+static void
+unload_window(void *obj, LoaderStack *ls)
+{
+  SDL_DestroyWindow(cg_core.window);
+}
+
+static SDL_bool
+load_sdl_renderer(void *obj, LoaderStack *ls)
+{
+  cg_core.renderer = NULL;
+  cg_core.renderer = SDL_CreateRenderer(
+      cg_core.window, -1, SDL_RENDERER_ACCELERATED |
+      SDL_RENDERER_TARGETTEXTURE);
+  if(cg_core.renderer == NULL)
+  {
+    const char* base_error = "Could not create SDL renderer → ";
+    LoaderStack_set_error(ls, base_error, SDL_GetError());
+    return SDL_FALSE;
+  }
+
+  return SDL_TRUE;
+}
+
+static void
+unload_sdl_renderer(void *obj, LoaderStack *ls)
+{
+  SDL_DestroyRenderer(cg_core.renderer);
+}
+
+static SDL_bool
+load_pre_screen(void *obj, LoaderStack *ls)
+{
+  cg_core.pre_screen_buffer = SDL_CreateTexture(
+      cg_core.renderer, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET,
+      cg_core.game_width, cg_core.game_height);
+
+  if(cg_core.pre_screen_buffer == NULL)
+  {
+    const char* base_error = "Could not create renderering buffer → ";
+    LoaderStack_set_error(ls, base_error, SDL_GetError());
+    return SDL_FALSE;
+  }
+
+  cg_Engine_calculate_full_scale();
+
+  SDL_SetRenderTarget(cg_core.renderer, cg_core.pre_screen_buffer);
+
+  return SDL_TRUE;
+}
+
+static void
+unload_pre_screen(void *obj, LoaderStack *ls)
+{
+  SDL_DestroyTexture(cg_core.pre_screen_buffer);
+}
+
+void
+cg_Core_init(LoaderStack *loader)
+{
+  LoaderStack_constructor(loader, NULL);
+
+  LoaderStack_add(loader, &load_variables, &unload_variables);
+  LoaderStack_add(loader, &load_sdl, &unload_sdl);
+  LoaderStack_add(loader, &load_sdl_image, &unload_sdl_image);
+  LoaderStack_add(loader, &load_sdl_mixer, &unload_sdl_mixer);
+  LoaderStack_add(loader, &load_sdl_open_audio, &unload_sdl_open_audio);
+  LoaderStack_add(loader, &load_sdl_ttf, &unload_sdl_ttf);
+  LoaderStack_add(loader, &load_window, &unload_window);
+  LoaderStack_add(loader, &load_sdl_renderer, &unload_sdl_renderer);
+  LoaderStack_add(loader, &load_pre_screen, &unload_pre_screen);
+}
+
+SDL_bool
+cg_Core_load(LoaderStack *loader)
+{
+  if(!LoaderStack_load(loader)) return SDL_FALSE;
+
+  return SDL_TRUE;
+}
+
+void
+cg_Core_unload(LoaderStack *loader)
+{
+  LoaderStack_destructor(loader);
+}
diff --git a/src/core.h b/src/core.h
new file mode 100644
index 0000000..e5d651a
--- /dev/null
+++ b/src/core.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_CORE_H
+#define CANDY_GEAR_CORE_H 1
+
+#include <mruby.h>
+#include <mruby/class.h>
+#include <mruby/compile.h>
+#include <mruby/data.h>
+#include <mruby/dump.h>
+#include <mruby/variable.h>
+
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_image.h>
+#include <SDL2/SDL_mixer.h>
+#include <SDL2/SDL_ttf.h>
+
+#include "loader.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * The Core class stores all global states that the engine needs to work.
+ * Global variables are not evil if you use them carefully.
+ */
+typedef struct
+{
+  const char *config_file;
+
+  /// Text displayed in the game window.
+  char *game_name;
+
+  /**
+   * @{
+   * This is the amount of pixel the games use to render a buffer. The image in
+   * this buffer is then rendered to the screen.
+   */
+  int game_width, game_height;
+  /// @}
+
+  /**
+   * @{
+   * This is the ammount of pixel that the games uses when rendering to the
+   * screen.
+   */
+  int screen_width, screen_height;
+  /// @}
+
+  Uint32 fps;
+  Uint32 max_frame_duration_ms;
+
+  SDL_Window *window;
+  SDL_Renderer *renderer;
+
+  /// All rendering goes here before they are moved to the screen.
+  SDL_Texture *pre_screen_buffer;
+  SDL_Rect screen_rect;
+
+  SDL_bool quit_game;
+} cg_sCore;
+
+extern cg_sCore cg_core;
+
+/// \memberof cg_sCore @{
+
+void
+cg_Core_init(LoaderStack *loader);
+
+SDL_bool
+cg_Core_load(LoaderStack *loader);
+
+void
+cg_Core_unload(LoaderStack *loader);
+
+/// @}
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_CORE_H */
diff --git a/src/font.c b/src/font.c
new file mode 100644
index 0000000..a333a30
--- /dev/null
+++ b/src/font.c
@@ -0,0 +1,60 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "font.h"
+#include <stdio.h>
+
+void
+cg_free_font(mrb_state *mrb, void* obj)
+{
+  struct cg_font *ptr = obj;
+
+  TTF_CloseFont(ptr->data);
+  mrb_free(mrb, ptr);
+}
+
+const struct mrb_data_type cg_font_type = {"CG_Font", cg_free_font };
+
+static mrb_value
+cg_cFont_initialize(mrb_state *mrb, mrb_value self)
+{
+  mrb_int font_size;
+  char *file_path;
+  struct cg_font *ptr;
+
+  mrb_get_args(mrb, "zi", &file_path, &font_size);
+  ptr = (struct cg_font *)DATA_PTR(self);
+  if(ptr) mrb_free(mrb, ptr);
+  ptr = (struct cg_font *)mrb_malloc(mrb, sizeof(struct cg_font));
+
+  ptr->data = TTF_OpenFont(file_path, font_size);
+  if(!ptr->data) mrb_raise(mrb, E_ARGUMENT_ERROR, TTF_GetError());
+
+  mrb_data_init(self, ptr, &cg_font_type);
+  return self;
+}
+
+void
+cg_font_init(mrb_state *mrb)
+{
+  struct RClass *cg_m, *cg_cFont;
+
+  cg_m = mrb_module_get(mrb, "CandyGear");
+  cg_cFont = mrb_define_class_under(mrb, cg_m, "Font", mrb->object_class);
+  MRB_SET_INSTANCE_TT(cg_cFont, MRB_TT_DATA);
+  mrb_define_method(
+    mrb, cg_cFont, "initialize", cg_cFont_initialize, MRB_ARGS_REQ(2));
+}
diff --git a/src/font.h b/src/font.h
new file mode 100644
index 0000000..55e4d16
--- /dev/null
+++ b/src/font.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_FONT_H
+#define CANDY_GEAR_FONT_H 1
+
+#include "core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct cg_font
+{
+  TTF_Font *data;
+};
+
+extern const struct mrb_data_type cg_font_type;
+
+void
+cg_font_init(mrb_state *mrb);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_FONT_H */
diff --git a/src/graphic.c b/src/graphic.c
new file mode 100644
index 0000000..b58c08c
--- /dev/null
+++ b/src/graphic.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "graphic.h"
+
+#include "color.h"
+
+static mrb_value
+cg_mGraphic_set_color(mrb_state *mrb, mrb_value self)
+{
+  struct cg_color *color;
+  mrb_get_args(mrb, "d", &color, &cg_color_type);
+
+  SDL_SetRenderDrawColor(
+    cg_core.renderer, color->data.r, color->data.g, color->data.b,
+    color->data.a);
+
+  return self;
+}
+
+static mrb_value
+cg_mGraphic_draw_point(mrb_state *mrb, mrb_value self)
+{
+  mrb_int x, y;
+  mrb_get_args(mrb, "ii", &x, &y);
+  SDL_RenderDrawPoint(cg_core.renderer, x, y);
+
+  return self;
+}
+
+static mrb_value
+cg_mGraphic_draw_line(mrb_state *mrb, mrb_value self)
+{
+  mrb_int x1, y1, x2, y2;
+  mrb_get_args(mrb, "iiii", &x1, &y1, &x2, &y2);
+  SDL_RenderDrawLine(cg_core.renderer, x1, y1, x2, y2);
+
+  return self;
+}
+
+void
+cg_graphic_init(mrb_state *mrb)
+{
+  struct RClass *cg_m, *cg_mGraphic;
+
+  cg_m = mrb_module_get(mrb, "CandyGear");
+  cg_mGraphic = mrb_define_module_under(mrb, cg_m, "Graphic");
+  mrb_define_class_method(
+    mrb, cg_mGraphic, "set_color", cg_mGraphic_set_color, MRB_ARGS_REQ(1));
+  mrb_define_class_method(
+    mrb, cg_mGraphic, "draw_point", cg_mGraphic_draw_point, MRB_ARGS_REQ(2));
+  mrb_define_class_method(
+    mrb, cg_mGraphic, "draw_line", cg_mGraphic_draw_line, MRB_ARGS_REQ(4));
+}
diff --git a/src/graphic.h b/src/graphic.h
new file mode 100644
index 0000000..3fe9b1e
--- /dev/null
+++ b/src/graphic.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_GRAPHIC_H
+#define CANDY_GEAR_GRAPHIC_H 1
+
+#include "core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void
+cg_graphic_init(mrb_state *mrb);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_GRAPHIC_H */
diff --git a/src/key.c b/src/key.c
new file mode 100644
index 0000000..01fc42a
--- /dev/null
+++ b/src/key.c
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "key.h"
+
+void
+cg_key_init(mrb_state *mrb)
+{
+  struct RClass *cg_m, *cg_mKey;
+
+  cg_m = mrb_module_get(mrb, "CandyGear");
+  cg_mKey = mrb_define_module_under(mrb, cg_m, "Key");
+
+  mrb_define_const(mrb, cg_mKey, "A", mrb_int_value(mrb, SDLK_a));
+  mrb_define_const(mrb, cg_mKey, "B", mrb_int_value(mrb, SDLK_b));
+  mrb_define_const(mrb, cg_mKey, "C", mrb_int_value(mrb, SDLK_c));
+  mrb_define_const(mrb, cg_mKey, "D", mrb_int_value(mrb, SDLK_d));
+  mrb_define_const(mrb, cg_mKey, "E", mrb_int_value(mrb, SDLK_e));
+  mrb_define_const(mrb, cg_mKey, "F", mrb_int_value(mrb, SDLK_f));
+  mrb_define_const(mrb, cg_mKey, "G", mrb_int_value(mrb, SDLK_g));
+  mrb_define_const(mrb, cg_mKey, "H", mrb_int_value(mrb, SDLK_h));
+  mrb_define_const(mrb, cg_mKey, "I", mrb_int_value(mrb, SDLK_i));
+  mrb_define_const(mrb, cg_mKey, "J", mrb_int_value(mrb, SDLK_j));
+  mrb_define_const(mrb, cg_mKey, "K", mrb_int_value(mrb, SDLK_k));
+  mrb_define_const(mrb, cg_mKey, "L", mrb_int_value(mrb, SDLK_l));
+  mrb_define_const(mrb, cg_mKey, "M", mrb_int_value(mrb, SDLK_m));
+  mrb_define_const(mrb, cg_mKey, "N", mrb_int_value(mrb, SDLK_n));
+  mrb_define_const(mrb, cg_mKey, "O", mrb_int_value(mrb, SDLK_o));
+  mrb_define_const(mrb, cg_mKey, "P", mrb_int_value(mrb, SDLK_p));
+  mrb_define_const(mrb, cg_mKey, "Q", mrb_int_value(mrb, SDLK_q));
+  mrb_define_const(mrb, cg_mKey, "R", mrb_int_value(mrb, SDLK_r));
+  mrb_define_const(mrb, cg_mKey, "S", mrb_int_value(mrb, SDLK_s));
+  mrb_define_const(mrb, cg_mKey, "T", mrb_int_value(mrb, SDLK_t));
+  mrb_define_const(mrb, cg_mKey, "U", mrb_int_value(mrb, SDLK_u));
+  mrb_define_const(mrb, cg_mKey, "V", mrb_int_value(mrb, SDLK_v));
+  mrb_define_const(mrb, cg_mKey, "W", mrb_int_value(mrb, SDLK_w));
+  mrb_define_const(mrb, cg_mKey, "X", mrb_int_value(mrb, SDLK_x));
+  mrb_define_const(mrb, cg_mKey, "Y", mrb_int_value(mrb, SDLK_y));
+  mrb_define_const(mrb, cg_mKey, "Z", mrb_int_value(mrb, SDLK_x));
+
+  mrb_define_const(mrb, cg_mKey, "UP", mrb_int_value(mrb, SDLK_UP));
+  mrb_define_const(mrb, cg_mKey, "DOWN", mrb_int_value(mrb, SDLK_DOWN));
+  mrb_define_const(mrb, cg_mKey, "LEFT", mrb_int_value(mrb, SDLK_LEFT));
+  mrb_define_const(mrb, cg_mKey, "RIGHT", mrb_int_value(mrb, SDLK_RIGHT));
+
+  mrb_define_const(
+    mrb, cg_mKey, "BACKSPACE", mrb_int_value(mrb, SDLK_BACKSPACE));
+  mrb_define_const(mrb, cg_mKey, "TAB", mrb_int_value(mrb, SDLK_TAB));
+  mrb_define_const(
+    mrb, cg_mKey, "LEFT_SHIFT", mrb_int_value(mrb, SDLK_LSHIFT));
+  mrb_define_const(
+    mrb, cg_mKey, "RIGHT_SHIFT", mrb_int_value(mrb, SDLK_RSHIFT));
+  mrb_define_const(mrb, cg_mKey, "SPACE", mrb_int_value(mrb, SDLK_SPACE));
+  mrb_define_const(mrb, cg_mKey, "LEFT_ALT", mrb_int_value(mrb, SDLK_LALT));
+  mrb_define_const(mrb, cg_mKey, "RIGHT_ALT", mrb_int_value(mrb, SDLK_RALT));
+  mrb_define_const(mrb, cg_mKey, "LEFT_CTRL", mrb_int_value(mrb, SDLK_LCTRL));
+  mrb_define_const(mrb, cg_mKey, "RIGHT_CTRL", mrb_int_value(mrb, SDLK_RCTRL));
+}
diff --git a/src/key.h b/src/key.h
new file mode 100644
index 0000000..5544518
--- /dev/null
+++ b/src/key.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_KEY_H
+#define CANDY_GEAR_KEY_H 1
+
+#include "core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void
+cg_key_init(mrb_state *mrb);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_KEY_H */
diff --git a/src/loader.c b/src/loader.c
new file mode 100644
index 0000000..c24d47e
--- /dev/null
+++ b/src/loader.c
@@ -0,0 +1,162 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+
+#include "loader.h"
+
+void
+LoaderStack_constructor(LoaderStack *self, void *obj)
+{
+  self->_last_loaded = 0;
+
+  self->_loader_capacity = 10; // Totally arbitrary value.
+  self->_loader_size = 0;
+
+  self->_obj = obj;
+
+  self->error_message = NULL;
+
+  self->_loaders = malloc(sizeof(Loader) * self->_loader_capacity);
+}
+
+void
+LoaderStack_destructor(LoaderStack *self)
+{
+  if(self->error_message != NULL)
+    free(self->error_message);
+
+  if(LoaderStack_is_loaded(self)) LoaderStack_unload(self);
+  free(self->_loaders);
+}
+
+static void
+LoaderStack_partial_unload(LoaderStack *self, int32_t step)
+{
+  // Already unloaded, nothing to do.
+  if(self->_last_loaded <= step) return;
+
+  for(; self->_last_loaded >= step; self->_last_loaded--)
+    if(self->_loaders[self->_last_loaded].unload != NULL)
+      self->_loaders[self->_last_loaded].unload(self->_obj, self);
+
+  // This number will be one before the last loaded after the unloading loop
+  // is over.
+  self->_last_loaded++;
+}
+
+SDL_bool
+LoaderStack_partial_load(LoaderStack *self, int32_t step)
+{
+  SDL_bool error = SDL_FALSE;
+
+  // Already loaded, nothing to do.
+  if(self->_last_loaded >= step) return SDL_TRUE;
+
+  for(;self->_last_loaded < step; self->_last_loaded++)
+  {
+    error = !self->_loaders[self->_last_loaded].load(self->_obj, self);
+    if(error) break;
+  }
+
+  // Self number will be one after the last loeaded after the loading loop is
+  // over.
+  self->_last_loaded--;
+
+  if(error) LoaderStack_partial_unload(self, 0);
+
+  return !error;
+}
+
+SDL_bool
+LoaderStack_is_loaded(LoaderStack *self)
+{
+  return self->_last_loaded > 0;
+}
+
+void
+LoaderStack_add(
+  LoaderStack *self,
+  SDL_bool (*load)(void *obj, LoaderStack *ls),
+  void (*unload)(void *obj, LoaderStack *ls))
+{
+  Loader *l;
+  uint32_t next_loader = self->_loader_size;
+
+  // Expand if is full.
+  if(self->_loader_size == self->_loader_capacity)
+  {
+    self->_loader_capacity += 5; // Totally arbitrary value.
+    self->_loaders = realloc(self->_loaders,
+			     sizeof(Loader) * self->_loader_capacity);
+  }
+
+  l = &(self->_loaders[next_loader]);
+  l->load = load;
+  l->unload = unload;
+
+  self->_loader_size++;
+}
+
+void
+LoaderStack_set_error(
+  LoaderStack *self, const char* base_error, const char* additional_error)
+{
+  if(self->error_message != NULL) free(self->error_message);
+
+  if(additional_error != NULL)
+  {
+    self->error_message =
+	malloc(strlen(base_error) + strlen(additional_error) + 1);
+
+    strcpy(self->error_message, base_error);
+    strcat(self->error_message, additional_error);
+  }
+  else
+  {
+    self->error_message = malloc(strlen(base_error));
+
+    strcpy(self->error_message, base_error);
+  }
+}
+
+SDL_bool
+LoaderStack_load(LoaderStack *self)
+{
+  if(LoaderStack_is_loaded(self)) return SDL_TRUE;
+
+  if(LoaderStack_partial_load(self, self->_loader_size))
+    return SDL_TRUE;
+  else
+    return SDL_FALSE;
+}
+
+SDL_bool
+LoaderStack_reload(LoaderStack *self)
+{
+  if(!LoaderStack_is_loaded(self)) return SDL_FALSE;
+
+  LoaderStack_partial_unload(self, self->_loader_size);
+  return LoaderStack_partial_load(self, self->_loader_size);
+}
+
+void
+LoaderStack_unload(LoaderStack *self)
+{
+  if(!LoaderStack_is_loaded(self)) return;
+
+  LoaderStack_partial_unload(self, 0);
+}
diff --git a/src/loader.h b/src/loader.h
new file mode 100644
index 0000000..93ec42b
--- /dev/null
+++ b/src/loader.h
@@ -0,0 +1,159 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_LOADER_STACK_H
+#define CANDY_GEAR_LOADER_STACK_H 1
+
+#include <SDL2/SDL.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct LoaderStack_s;
+
+/**
+ * Stores a reversible action.
+ */
+typedef struct
+{
+  SDL_bool (*load)(void *obj, struct LoaderStack_s *ls);
+  void (*unload)(void *obj, struct LoaderStack_s *ls);
+} Loader;
+
+/**
+ * Stores a sequence of functions that must be executed and rolled back in
+ * order.
+ *
+ * For example, if the variable _loaders contain A→B→C→D→E, it will load A,
+ * then B, then C, etc. If D fails, it unloads C, then B, then A.
+ */
+struct LoaderStack_s
+{
+  void *_obj;
+
+  int32_t _last_loaded;
+
+  uint32_t _loader_capacity;
+  uint32_t _loader_size;
+  Loader *_loaders;
+
+  char* error_message;
+};
+
+typedef struct LoaderStack_s LoaderStack;
+
+/// \memberof LoaderStack_s @{
+
+/**
+ * Must be called to initialize the variables.
+ *
+ * @param[self] a pointer to the LoaderStack_s to be initalized.
+ * @param[obj] a pointer to an struct that will be send to every function
+ *   inside the _loaders.
+ */
+void
+LoaderStack_constructor(LoaderStack *self, void *obj);
+
+/**
+ * Must be called to finalize the variables and cleanup memory.
+ *
+ * @param[self] a pointer to the LoaderStack_s to be finalized.
+ */
+void
+LoaderStack_destructor(LoaderStack *self);
+
+/**
+ * Adds a reversible action to the loader. The first action added is the first
+ * to de executed the last rolled back, and so on. Those functions are stored
+ * inside _loaders.
+ *
+ * @param[self] a pointer to the LoaderStack_s hat stores the action.
+ * @param[load] the do action. The function pointed by this variable must
+ *   return SDL_TRUE on success and SDL_FALSE on fail.
+ * @param[unload] the undo/rollback action, if the action do not need a
+ *   rollback, this pointer can be set to null.
+ */
+void
+LoaderStack_add(
+  LoaderStack *self,
+  SDL_bool (*load)(void *obj, LoaderStack *ls),
+  void (*unload)(void *obj, LoaderStack *ls));
+
+/**
+ * Can be used to set error before returning SDL_FALSE from a function used by
+ * _loaders
+ *
+ * @param[self] a pointer to the LoaderStack_s where the error happened.
+ * @param[base_error] the error message.
+ * @param[additional_error] if you need to concatenate two error messages, use
+ *   this variable to a second message. Otherwise set to NULL.
+ */
+void
+LoaderStack_set_error(
+  LoaderStack *self, const char* base_error, const char* additional_error);
+
+/**
+ * @return SDL_TRUE if you successfuly executed LoaderStack_load or
+ *   LoaderStack_reload in the LoaderStack. SDL_FALSE after
+ *   LoaderStack_constructor or LoaderStack_unload is executed.
+ */
+SDL_bool
+LoaderStack_is_loaded(LoaderStack *self);
+
+/**
+ * Execute some of the load functions in the _loaders. If one of them fails,
+ * roll back everything inside _loaders. The LoaderStack knows which functions
+ * it already executed and will not rerun them unless they are rolled back
+ * first.
+ *
+ * @param[step] the number of functions to be executed.
+ * @return SDL_TRUE on success and SDL_FALSE on fail.
+ */
+SDL_bool
+LoaderStack_partial_load(LoaderStack *self, int32_t step);
+
+/**
+ * Execute all of the load functions in the _loaders. If one of them fails,
+ * roll back everything inside _loaders.
+ * @return SDL_TRUE on success and SDL_FALSE on fail.
+ */
+SDL_bool
+LoaderStack_load(LoaderStack *self);
+
+/**
+ * Roll back all loaded function inside loaders, if there are any. Then execute
+ * all of the load functions in the _loaders. If one of them fails, roll back
+ * everything inside _loaders.
+ *
+ * @return SDL_TRUE on success and SDL_FALSE on fail.
+ */
+SDL_bool
+LoaderStack_reload(LoaderStack *self);
+
+/**
+ * Roll back all loaded function inside loaders, if there are any.
+ */
+void
+LoaderStack_unload(LoaderStack *self);
+
+/// @}
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_LOADER_STACK_H */
diff --git a/src/log.c b/src/log.c
new file mode 100644
index 0000000..92862ae
--- /dev/null
+++ b/src/log.c
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "log.h"
+
+#include <stdio.h>
+
+static mrb_value
+cg_mLog_info(mrb_state *mrb, mrb_value self)
+{
+  const char *message;
+  mrb_get_args(mrb, "z", &message);
+  printf("%s\n", message);
+
+  return self;
+}
+
+void
+cg_log_init(mrb_state *mrb)
+{
+  struct RClass *cg_m, *cg_mLog;
+  cg_m = mrb_module_get(mrb, "CandyGear");
+  cg_mLog = mrb_define_module_under(mrb, cg_m, "Log");
+  mrb_define_class_method(mrb, cg_mLog, "info", cg_mLog_info, MRB_ARGS_REQ(1));
+}
diff --git a/src/log.h b/src/log.h
new file mode 100644
index 0000000..0196908
--- /dev/null
+++ b/src/log.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_LOG_H
+#define CANDY_GEAR_LOG_H 1
+
+#include "core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void
+cg_log_init(mrb_state *mrb);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_LOG_H */
diff --git a/src/main.cpp b/src/main.cpp
new file mode 100644
index 0000000..8ebe77c
--- /dev/null
+++ b/src/main.cpp
@@ -0,0 +1,151 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "candy_gear.h"
+#include "color.h"
+#include "core.h"
+#include "font.h"
+#include "graphic.h"
+#include "key.h"
+#include "log.h"
+#include "palette.h"
+#include "point.h"
+#include "rect.h"
+#include "sound.h"
+#include "sprite.h"
+#include "texture.h"
+
+cg_sCore cg_core;
+
+void handle_error(mrb_state *mrb)
+{
+    mrb_print_error(mrb);
+    cg_core.quit_game = SDL_TRUE;
+}
+
+int main(int argc, char *argv[])
+{
+  SDL_Event event;
+  Uint32 frame_start;
+
+  mrb_state *mrb = mrb_open();
+  mrb_value main_obj;
+  mrb_sym sym_init, sym_key_down, sym_key_up, sym_quit, sym_tick;
+  FILE *fp;
+
+  LoaderStack core_loader;
+
+  cg_core.config_file = argv[1];
+
+  cg_Core_init(&core_loader);
+  if(!cg_Core_load(&core_loader)) return 1;
+
+  if (!mrb) { /* handle error */ }
+  mrb_define_module(mrb, "CandyGear");
+  cg_candy_gear_init(mrb);
+  cg_color_init(mrb);
+  cg_font_init(mrb);
+  cg_graphic_init(mrb);
+  cg_key_init(mrb);
+  cg_log_init(mrb);
+  cg_palette_init(mrb);
+  cg_point_init(mrb);
+  cg_rect_init(mrb);
+  cg_sound_init(mrb);
+  cg_sprite_init(mrb);
+  cg_texture_init(mrb);
+
+  main_obj = mrb_obj_iv_inspect(mrb, mrb->top_self);
+  sym_init = mrb_intern_cstr(mrb, "init");
+  sym_key_down = mrb_intern_cstr(mrb, "key_down");
+  sym_key_up = mrb_intern_cstr(mrb, "key_up");
+  sym_quit = mrb_intern_cstr(mrb, "quit");
+  sym_tick = mrb_intern_cstr(mrb, "tick");
+
+  fp = fopen(argv[2], "r");
+  mrb_load_irep_file(mrb, fp);
+  fclose(fp);
+  if (mrb->exc) handle_error(mrb);
+
+  mrb_funcall_id(mrb, main_obj, sym_init, 0);
+  if (mrb->exc) handle_error(mrb);
+
+  frame_start = SDL_GetTicks();
+
+  // Game main loop.
+  while(!cg_core.quit_game)
+  {
+    // Get input.
+    while(SDL_PollEvent(&event) != 0)
+    {
+      switch(event.type)
+      {
+      case SDL_KEYDOWN:
+	mrb_funcall_id(
+	  mrb, main_obj, sym_key_down, 1,
+	  mrb_int_value(mrb, event.key.keysym.sym));
+	break;
+      case SDL_KEYUP:
+	mrb_funcall_id(
+	  mrb, main_obj, sym_key_up, 1,
+	  mrb_int_value(mrb, event.key.keysym.sym));
+	break;
+      case SDL_MOUSEMOTION:
+	break;
+      case SDL_MOUSEBUTTONDOWN:
+	break;
+      case SDL_MOUSEBUTTONUP:
+	break;
+      case SDL_QUIT:
+	mrb_funcall_id(mrb, main_obj, sym_quit, 0);
+	break;
+      }
+    }
+
+    // Clear buffer.
+    SDL_SetRenderDrawColor(cg_core.renderer, 0x00, 0x00, 0x00, 0xff);
+    SDL_RenderClear(cg_core.renderer);
+
+    mrb_funcall_id(mrb, main_obj, sym_tick, 0);
+    if (mrb->exc) handle_error(mrb);
+
+    // Copy buffer to the screen and display it.
+    SDL_SetRenderTarget(cg_core.renderer, NULL);
+    SDL_RenderCopy(
+      cg_core.renderer, cg_core.pre_screen_buffer, NULL, &cg_core.screen_rect);
+    SDL_RenderPresent(cg_core.renderer);
+    SDL_SetRenderTarget(cg_core.renderer, cg_core.pre_screen_buffer);
+
+    // Timer
+    {
+      Uint32 frame_stop, frame_duration;
+
+      frame_stop = SDL_GetTicks();
+      frame_duration = frame_stop - frame_start;
+
+      // If frame take less time than maximum allowed.
+      if(cg_core.max_frame_duration_ms > frame_duration)
+	SDL_Delay(cg_core.max_frame_duration_ms - frame_duration);
+
+      frame_start = frame_stop;
+    }
+  }
+
+  mrb_close(mrb);
+  cg_Core_unload(&core_loader);
+
+  return 0;
+}
diff --git a/src/palette.c b/src/palette.c
new file mode 100644
index 0000000..9f98dc6
--- /dev/null
+++ b/src/palette.c
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "palette.h"
+#include "palette_implementation.h"
+
+void
+cg_free_palette(mrb_state *mrb, void* obj)
+{
+  struct cg_palette *ptr = obj;
+
+  mrb_free(mrb, ptr);
+}
+
+const struct mrb_data_type cg_palette_type = {
+  "CG_Palette", cg_free_palette };
+
+static mrb_value
+cg_cPalette_initialize(mrb_state *mrb, mrb_value self)
+{
+  const char *file_path;
+  struct cg_palette *ptr;
+
+  mrb_get_args(mrb, "z", &file_path);
+  ptr = (struct cg_palette *)DATA_PTR(self);
+  if(ptr) mrb_free(mrb, ptr);
+  ptr = (struct cg_palette *)mrb_malloc(mrb, sizeof(struct cg_palette));
+
+  cg_pallet_load_yaml(ptr, file_path);
+
+  mrb_data_init(self, ptr, &cg_palette_type);
+  return self;
+}
+
+void
+cg_palette_init(mrb_state *mrb)
+{
+  struct RClass *cg_m, *cg_cPalette;
+
+  cg_m = mrb_module_get(mrb, "CandyGear");
+  cg_cPalette = mrb_define_class_under(mrb, cg_m, "Palette", mrb->object_class);
+  MRB_SET_INSTANCE_TT(cg_cPalette, MRB_TT_DATA);
+  mrb_define_method(
+    mrb, cg_cPalette, "initialize", cg_cPalette_initialize, MRB_ARGS_REQ(1));
+}
diff --git a/src/palette.h b/src/palette.h
new file mode 100644
index 0000000..b9e52c2
--- /dev/null
+++ b/src/palette.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_PALETTE_H
+#define CANDY_GEAR_PALETTE_H 1
+
+#include "core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct cg_palette
+{
+  SDL_Color colors[256];
+};
+
+extern const struct mrb_data_type cg_palette_type;
+
+void
+cg_palette_init(mrb_state *mrb);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_PALETTE_H */
diff --git a/src/palette_implementation.cpp b/src/palette_implementation.cpp
new file mode 100644
index 0000000..7f85c6a
--- /dev/null
+++ b/src/palette_implementation.cpp
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "palette_implementation.h"
+
+#include <string>
+
+#include <yaml-cpp/yaml.h>
+
+void cg_pallet_load_yaml(struct cg_palette *palette, const char *file_path)
+{
+  YAML::Node root = YAML::LoadFile(file_path);
+  for(std::size_t i = 0; i < root.size(); i++)
+  {
+    std::string color = root[i].as<std::string>();
+
+    palette->colors[i].r = std::stoi(color.substr(0, 2), nullptr, 16);
+    palette->colors[i].g = std::stoi(color.substr(2, 2), nullptr, 16);
+    palette->colors[i].b = std::stoi(color.substr(4, 2), nullptr, 16);
+    palette->colors[i].a = std::stoi(color.substr(6, 2), nullptr, 16);
+  }
+}
diff --git a/src/palette_implementation.h b/src/palette_implementation.h
new file mode 100644
index 0000000..50c9ef3
--- /dev/null
+++ b/src/palette_implementation.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_PALETTE_IMPLEMENTATION_H
+#define CANDY_GEAR_PALETTE_IMPLEMENTATION_H 1
+
+#include "palette.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void
+cg_pallet_load_yaml(struct cg_palette *palette, const char *file_path);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_PALETTE_IMPLEMENTATION_H */
diff --git a/src/pgm_image.cpp b/src/pgm_image.cpp
new file mode 100644
index 0000000..a88455c
--- /dev/null
+++ b/src/pgm_image.cpp
@@ -0,0 +1,70 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "pgm_image.h"
+
+#include <cstring>
+#include <charconv>
+#include <fstream>
+#include <string>
+
+SDL_bool PGMImage_constructor(PGMImage *self, const char *file_path)
+{
+  self->data = nullptr;
+  int wh_pos;
+  std::string line;
+  std::ifstream file(file_path);
+
+  if(!file)
+  {
+    self->error = "Failed to open PGM file";
+    return SDL_FALSE;
+  }
+
+  // Read file magic.
+  std::getline(file, line);
+  if(line != "P5")
+  {
+    self->error = "PGM file contains a invalid magic";
+    return SDL_FALSE;
+  }
+
+  // Read file comment.
+  std::getline(file, line);
+
+  // Read file width and height.
+  std::getline(file, line);
+  wh_pos = line.find(" ");
+  std::from_chars(line.data(), line.data() + wh_pos, self->width);
+  std::from_chars(
+      line.data() + wh_pos + 1, line.data() + line.size(), self->height);
+
+  // Read file maximum value.
+  std::getline(file, line);
+  std::from_chars(line.data(), line.data() + line.size(), self->max_value);
+
+  // Read file values.
+  self->data_size = self->width * self->height;
+  self->data = new char[self->data_size];
+  file.read(self->data, self->data_size);
+
+  return SDL_TRUE;
+}
+
+void PGMImage_destructor(PGMImage *self)
+{
+  if(self->data != nullptr) delete[] self->data;
+}
diff --git a/src/pgm_image.h b/src/pgm_image.h
new file mode 100644
index 0000000..5a271d0
--- /dev/null
+++ b/src/pgm_image.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_PGM_IMAGE_H
+#define CANDY_GEAR_PGM_IMAGE_H 1
+
+#include <SDL2/SDL.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct PGMImage_s
+{
+  int width, height, max_value, data_size;
+  char *data;
+  const char *error;
+};
+
+typedef struct PGMImage_s PGMImage;
+
+SDL_bool PGMImage_constructor(PGMImage *self, const char *file_path);
+void PGMImage_destructor(PGMImage *self);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_PGM_IMAGE_H */
diff --git a/src/point.c b/src/point.c
new file mode 100644
index 0000000..4d11480
--- /dev/null
+++ b/src/point.c
@@ -0,0 +1,122 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "point.h"
+
+void
+cg_free_point(mrb_state *mrb, void* obj)
+{
+  struct cg_point *ptr = obj;
+
+  mrb_free(mrb, ptr);
+}
+
+const struct mrb_data_type cg_point_type = {
+  "CG_Point", cg_free_point };
+
+static mrb_value
+cg_cPoint_initialize(mrb_state *mrb, mrb_value self)
+{
+  mrb_int x, y;
+  struct cg_point *ptr;
+
+  mrb_get_args(mrb, "ii", &x, &y);
+  ptr = (struct cg_point *)DATA_PTR(self);
+  if(ptr) mrb_free(mrb, ptr);
+  ptr = (struct cg_point *)mrb_malloc(mrb, sizeof(struct cg_point));
+
+  ptr->data.x = x;
+  ptr->data.y = y;
+
+  mrb_data_init(self, ptr, &cg_point_type);
+  return self;
+}
+
+static mrb_value
+cg_cPoint_get_x(mrb_state *mrb, mrb_value self)
+{
+  struct cg_point *ptr;
+
+  ptr = (struct cg_point *)DATA_PTR(self);
+
+  return mrb_int_value(mrb, ptr->data.x);
+}
+
+static mrb_value
+cg_cPoint_set_x(mrb_state *mrb, mrb_value self)
+{
+  mrb_int x;
+  struct cg_point *ptr;
+
+  mrb_get_args(mrb, "i", &x);
+  ptr = (struct cg_point *)DATA_PTR(self);
+
+  ptr->data.x = x;
+
+  return mrb_int_value(mrb, ptr->data.x);
+}
+
+static mrb_value
+cg_cPoint_get_y(mrb_state *mrb, mrb_value self)
+{
+  struct cg_point *ptr;
+
+  ptr = (struct cg_point *)DATA_PTR(self);
+
+  return mrb_int_value(mrb, ptr->data.y);
+}
+
+static mrb_value
+cg_cPoint_set_y(mrb_state *mrb, mrb_value self)
+{
+  mrb_int y;
+  struct cg_point *ptr;
+
+  mrb_get_args(mrb, "i", &y);
+  ptr = (struct cg_point *)DATA_PTR(self);
+
+  ptr->data.y = y;
+
+  return mrb_int_value(mrb, ptr->data.y);
+}
+
+static mrb_value
+cg_cPoint_draw(mrb_state *mrb, mrb_value self)
+{
+  struct cg_point *ptr;
+  ptr = (struct cg_point *)DATA_PTR(self);
+  SDL_RenderDrawPoint(cg_core.renderer, ptr->data.x, ptr->data.y);
+
+  return self;
+}
+
+void
+cg_point_init(mrb_state *mrb)
+{
+  struct RClass *cg_m, *cg_cPoint;
+
+  cg_m = mrb_module_get(mrb, "CandyGear");
+  cg_cPoint = mrb_define_class_under(
+    mrb, cg_m, "Point", mrb->object_class);
+  MRB_SET_INSTANCE_TT(cg_cPoint, MRB_TT_DATA);
+  mrb_define_method(
+    mrb, cg_cPoint, "initialize", cg_cPoint_initialize, MRB_ARGS_REQ(2));
+  mrb_define_method(mrb, cg_cPoint, "x", cg_cPoint_get_x, MRB_ARGS_NONE());
+  mrb_define_method(mrb, cg_cPoint, "x=", cg_cPoint_set_x, MRB_ARGS_REQ(1));
+  mrb_define_method(mrb, cg_cPoint, "y", cg_cPoint_get_y, MRB_ARGS_NONE());
+  mrb_define_method(mrb, cg_cPoint, "y=", cg_cPoint_set_y, MRB_ARGS_REQ(1));
+  mrb_define_method(mrb, cg_cPoint, "draw", cg_cPoint_draw, MRB_ARGS_NONE());
+}
diff --git a/src/point.h b/src/point.h
new file mode 100644
index 0000000..7507d62
--- /dev/null
+++ b/src/point.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_POINT_H
+#define CANDY_GEAR_POINT_H 1
+
+#include "core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct cg_point
+{
+  SDL_Point data;
+};
+
+extern const struct mrb_data_type cg_point_type;
+
+void
+cg_point_init(mrb_state *mrb);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_POINT_H */
diff --git a/src/rect.c b/src/rect.c
new file mode 100644
index 0000000..206ab45
--- /dev/null
+++ b/src/rect.c
@@ -0,0 +1,209 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "rect.h"
+
+void
+cg_free_rect(mrb_state *mrb, void* obj)
+{
+  struct cg_rect *ptr = obj;
+
+  mrb_free(mrb, ptr);
+}
+
+const struct mrb_data_type cg_rect_type = {
+  "CG_Rect", cg_free_rect };
+
+static mrb_value
+cg_cRect_initialize(mrb_state *mrb, mrb_value self)
+{
+  mrb_int x, y, width, height;
+  struct cg_rect *ptr;
+
+  mrb_get_args(mrb, "iiii", &x, &y, &width, &height);
+  ptr = (struct cg_rect *)DATA_PTR(self);
+  if(ptr) mrb_free(mrb, ptr);
+  ptr = (struct cg_rect *)mrb_malloc(mrb, sizeof(struct cg_rect));
+
+  ptr->rect.x = x;
+  ptr->rect.y = y;
+  ptr->rect.w = width;
+  ptr->rect.h = height;
+
+  mrb_data_init(self, ptr, &cg_rect_type);
+  return self;
+}
+
+static mrb_value
+cg_cRect_get_x(mrb_state *mrb, mrb_value self)
+{
+  struct cg_rect *ptr;
+
+  ptr = (struct cg_rect *)DATA_PTR(self);
+
+  return mrb_int_value(mrb, ptr->rect.x);
+}
+
+static mrb_value
+cg_cRect_set_x(mrb_state *mrb, mrb_value self)
+{
+  mrb_int x;
+  struct cg_rect *ptr;
+
+  mrb_get_args(mrb, "i", &x);
+  ptr = (struct cg_rect *)DATA_PTR(self);
+
+  ptr->rect.x = x;
+
+  return mrb_int_value(mrb, ptr->rect.x);
+}
+
+static mrb_value
+cg_cRect_get_y(mrb_state *mrb, mrb_value self)
+{
+  struct cg_rect *ptr;
+
+  ptr = (struct cg_rect *)DATA_PTR(self);
+
+  return mrb_int_value(mrb, ptr->rect.y);
+}
+
+static mrb_value
+cg_cRect_set_y(mrb_state *mrb, mrb_value self)
+{
+  mrb_int y;
+  struct cg_rect *ptr;
+
+  mrb_get_args(mrb, "i", &y);
+  ptr = (struct cg_rect *)DATA_PTR(self);
+
+  ptr->rect.y = y;
+
+  return mrb_int_value(mrb, ptr->rect.y);
+}
+
+static mrb_value
+cg_cRect_get_width(mrb_state *mrb, mrb_value self)
+{
+  struct cg_rect *ptr;
+
+  ptr = (struct cg_rect *)DATA_PTR(self);
+
+  return mrb_int_value(mrb, ptr->rect.w);
+}
+
+static mrb_value
+cg_cRect_set_width(mrb_state *mrb, mrb_value self)
+{
+  mrb_int width;
+  struct cg_rect *ptr;
+
+  mrb_get_args(mrb, "i", &width);
+  ptr = (struct cg_rect *)DATA_PTR(self);
+
+  ptr->rect.w = width;
+
+  return mrb_int_value(mrb, ptr->rect.w);
+}
+
+static mrb_value
+cg_cRect_get_height(mrb_state *mrb, mrb_value self)
+{
+  struct cg_rect *ptr;
+
+  ptr = (struct cg_rect *)DATA_PTR(self);
+
+  return mrb_int_value(mrb, ptr->rect.h);
+}
+
+static mrb_value
+cg_cRect_set_height(mrb_state *mrb, mrb_value self)
+{
+  mrb_int height;
+  struct cg_rect *ptr;
+
+  mrb_get_args(mrb, "i", &height);
+  ptr = (struct cg_rect *)DATA_PTR(self);
+
+  ptr->rect.h = height;
+
+  return mrb_int_value(mrb, ptr->rect.h);
+}
+
+static mrb_value
+cg_cRect_draw_lines(mrb_state *mrb, mrb_value self)
+{
+  struct cg_rect *ptr;
+  ptr = (struct cg_rect *)DATA_PTR(self);
+  SDL_RenderDrawRect(cg_core.renderer, &ptr->rect);
+
+  return self;
+}
+
+static mrb_value
+cg_cRect_draw_fill(mrb_state *mrb, mrb_value self)
+{
+  struct cg_rect *ptr;
+  ptr = (struct cg_rect *)DATA_PTR(self);
+  SDL_RenderFillRect(cg_core.renderer, &ptr->rect);
+
+  return self;
+}
+
+static mrb_value
+cg_cRect_collide(mrb_state *mrb, mrb_value self)
+{
+  struct cg_rect *ptr, *that;
+
+  mrb_get_args(mrb, "d", &that, &cg_rect_type);
+  ptr = (struct cg_rect *)DATA_PTR(self);
+
+  return mrb_bool_value(
+    ptr->rect.x <= that->rect.x + that->rect.w &&
+    ptr->rect.x + ptr->rect.w >= that->rect.x &&
+    ptr->rect.y <= that->rect.y + that->rect.h &&
+    ptr->rect.y + ptr->rect.h >= that->rect.y);
+}
+
+void
+cg_rect_init(mrb_state *mrb)
+{
+  struct RClass *cg_m, *cg_cRect;
+
+  cg_m = mrb_module_get(mrb, "CandyGear");
+  cg_cRect = mrb_define_class_under(mrb, cg_m, "Rect", mrb->object_class);
+  MRB_SET_INSTANCE_TT(cg_cRect, MRB_TT_DATA);
+  mrb_define_method(
+    mrb, cg_cRect, "initialize", cg_cRect_initialize, MRB_ARGS_REQ(4));
+  mrb_define_method(mrb, cg_cRect, "x", cg_cRect_get_x, MRB_ARGS_NONE());
+  mrb_define_method(mrb, cg_cRect, "x=", cg_cRect_set_x, MRB_ARGS_REQ(1));
+  mrb_define_method(mrb, cg_cRect, "y", cg_cRect_get_y, MRB_ARGS_NONE());
+  mrb_define_method(mrb, cg_cRect, "y=", cg_cRect_set_y, MRB_ARGS_REQ(1));
+  mrb_define_method(
+    mrb, cg_cRect, "width", cg_cRect_get_width, MRB_ARGS_NONE());
+  mrb_define_method(
+    mrb, cg_cRect, "width=", cg_cRect_set_width, MRB_ARGS_REQ(1));
+  mrb_define_method(
+    mrb, cg_cRect, "height", cg_cRect_get_height, MRB_ARGS_NONE());
+  mrb_define_method(
+    mrb, cg_cRect, "height=", cg_cRect_set_height, MRB_ARGS_REQ(1));
+  mrb_define_method(
+    mrb, cg_cRect, "draw_lines", cg_cRect_draw_lines, MRB_ARGS_NONE());
+  mrb_define_method(
+    mrb, cg_cRect, "draw_fill", cg_cRect_draw_fill, MRB_ARGS_NONE());
+  mrb_define_method(
+    mrb, cg_cRect, "collide?", cg_cRect_collide, MRB_ARGS_REQ(1));
+}
diff --git a/src/rect.h b/src/rect.h
new file mode 100644
index 0000000..64a7ba0
--- /dev/null
+++ b/src/rect.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_RECT_H
+#define CANDY_GEAR_RECT_H 1
+
+#include "core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct cg_rect
+{
+  SDL_Rect rect;
+};
+
+extern const struct mrb_data_type cg_rect_type;
+
+void
+cg_rect_init(mrb_state *mrb);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_RECT_H */
diff --git a/src/sound.c b/src/sound.c
new file mode 100644
index 0000000..8ca009c
--- /dev/null
+++ b/src/sound.c
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "sound.h"
+
+void
+cg_free_sound(mrb_state *mrb, void* obj)
+{
+  struct cg_sound *ptr = obj;
+
+  Mix_FreeChunk(ptr->chunk);
+  mrb_free(mrb, ptr);
+}
+
+const struct mrb_data_type cg_sound_type = {
+  "CG_Sound", cg_free_sound };
+
+static mrb_value
+cg_cSound_initialize(mrb_state *mrb, mrb_value self)
+{
+  const char *file_path;
+
+  struct cg_sound *ptr;
+
+  mrb_get_args(mrb, "z", &file_path);
+  ptr = (struct cg_sound *)DATA_PTR(self);
+  if(ptr) mrb_free(mrb, ptr);
+  ptr = (struct cg_sound *)mrb_malloc(mrb, sizeof(struct cg_sound));
+
+  ptr->chunk = Mix_LoadWAV(file_path);
+  if(ptr->chunk == NULL) mrb_raise(mrb, E_RUNTIME_ERROR, Mix_GetError());
+
+  mrb_data_init(self, ptr, &cg_sound_type);
+  return self;
+}
+
+static mrb_value
+cg_cSound_play(mrb_state *mrb, mrb_value self)
+{
+  struct cg_sound *ptr;
+
+  ptr = (struct cg_sound *)DATA_PTR(self);
+
+  Mix_PlayChannel(-1, ptr->chunk, 0);
+
+  return self;
+}
+
+void
+cg_sound_init(mrb_state *mrb)
+{
+  struct RClass *cg_m, *cg_cSound;
+
+  cg_m = mrb_module_get(mrb, "CandyGear");
+  cg_cSound = mrb_define_class_under(mrb, cg_m, "Sound", mrb->object_class);
+  MRB_SET_INSTANCE_TT(cg_cSound, MRB_TT_DATA);
+  mrb_define_method(
+    mrb, cg_cSound, "initialize", cg_cSound_initialize, MRB_ARGS_REQ(1));
+  mrb_define_method(mrb, cg_cSound, "play", cg_cSound_play, MRB_ARGS_NONE());
+}
diff --git a/src/sound.h b/src/sound.h
new file mode 100644
index 0000000..f2cd2e7
--- /dev/null
+++ b/src/sound.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_SOUND_H
+#define CANDY_GEAR_SOUND_H 1
+
+#include "core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct cg_sound
+{
+  Mix_Chunk *chunk;
+};
+
+extern const struct mrb_data_type cg_sound_type;
+
+void
+cg_sound_init(mrb_state *mrb);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_SOUND_H */
diff --git a/src/sprite.c b/src/sprite.c
new file mode 100644
index 0000000..b8495d4
--- /dev/null
+++ b/src/sprite.c
@@ -0,0 +1,198 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "sprite.h"
+#include "sprite_implementation.h"
+
+#include <mruby/hash.h>
+
+#include "point.h"
+#include "texture.h"
+
+// This variable works as a constant
+static mrb_sym id_at_texture;
+
+void
+cg_free_sprite(mrb_state *mrb, void* obj)
+{
+  struct cg_sprite *ptr = obj;
+
+  mrb_free(mrb, ptr);
+}
+
+const struct mrb_data_type cg_sprite_type = {
+  "CG_Sprite", cg_free_sprite };
+
+static mrb_value
+cg_cSrpite_load_yaml(mrb_state *mrb, mrb_value klass)
+{
+  const char *file_path;
+  struct cg_SpriteArray_s sprite_ary;
+  mrb_value hash, texture;
+
+  mrb_get_args(mrb, "zo", &file_path, &texture);
+
+  if(!cg_SpriteArray_constructor(&sprite_ary, file_path))
+    mrb_raise(mrb, E_RUNTIME_ERROR, "failed to open sprites");
+
+  hash = mrb_hash_new_capa(mrb, sprite_ary.len);
+
+  for(int i = 0; i < sprite_ary.len; i++)
+  {
+    mrb_hash_set(
+      mrb, hash,
+      mrb_symbol_value(mrb_intern_cstr(mrb, sprite_ary.sprites[i].name)),
+      mrb_funcall(
+        mrb, klass, "new", 5,
+        texture,
+        mrb_int_value(mrb, sprite_ary.sprites[i].x),
+        mrb_int_value(mrb, sprite_ary.sprites[i].y),
+        mrb_int_value(mrb, sprite_ary.sprites[i].width),
+        mrb_int_value(mrb, sprite_ary.sprites[i].height)));
+  }
+
+  cg_SpriteArray_destructor(&sprite_ary);
+
+  return hash;
+}
+
+static mrb_value
+cg_cSprite_initialize(mrb_state *mrb, mrb_value self)
+{
+  mrb_value texture_v;
+  mrb_int x, y, width, height;
+  struct cg_sprite *ptr;
+
+  mrb_get_args(mrb, "oiiii", &texture_v, &x, &y, &width, &height);
+  ptr = (struct cg_sprite *)DATA_PTR(self);
+  if(ptr) mrb_free(mrb, ptr);
+  ptr = (struct cg_sprite *)mrb_malloc(mrb, sizeof(struct cg_sprite));
+
+  mrb_iv_set(mrb, self, id_at_texture, texture_v);
+  ptr->rect.x = x;
+  ptr->rect.y = y;
+  ptr->rect.w = width;
+  ptr->rect.h = height;
+
+  mrb_data_init(self, ptr, &cg_sprite_type);
+  return self;
+}
+
+static mrb_value
+cg_cSprite_texture(mrb_state *mrb, mrb_value self)
+{
+  return mrb_iv_get(mrb, self, id_at_texture);
+}
+
+static mrb_value
+cg_cSprite_width(mrb_state *mrb, mrb_value self)
+{
+  struct cg_sprite *ptr;
+
+  ptr = (struct cg_sprite *)DATA_PTR(self);
+
+  return mrb_int_value(mrb, ptr->rect.w);
+}
+
+static mrb_value
+cg_cSprite_height(mrb_state *mrb, mrb_value self)
+{
+  struct cg_sprite *ptr;
+
+  ptr = (struct cg_sprite *)DATA_PTR(self);
+
+  return mrb_int_value(mrb, ptr->rect.h);
+}
+
+static mrb_value
+cg_cSprite_draw(mrb_state *mrb, mrb_value self)
+{
+  SDL_Rect dst_rect;
+
+  mrb_value texture_v;
+
+  struct cg_sprite *ptr;
+  struct cg_texture *texture_ptr;
+  struct cg_point *point;
+
+  mrb_get_args(mrb, "d", &point, &cg_point_type);
+
+  ptr = (struct cg_sprite *)DATA_PTR(self);
+  texture_v = mrb_iv_get(mrb, self, id_at_texture);
+  texture_ptr = (struct cg_texture *)DATA_PTR(texture_v);
+
+  dst_rect.x = point->data.x;
+  dst_rect.y = point->data.y;
+  dst_rect.w = ptr->rect.w;
+  dst_rect.h = ptr->rect.h;
+
+  SDL_RenderCopy(cg_core.renderer, texture_ptr->data, &ptr->rect, &dst_rect);
+
+  return self;
+}
+
+static mrb_value
+cg_cSprite_draw_xy(mrb_state *mrb, mrb_value self)
+{
+  SDL_Rect dst_rect;
+
+  mrb_value texture_v;
+
+  mrb_int x, y;
+  struct cg_sprite *ptr;
+  struct cg_texture *texture_ptr;
+
+  mrb_get_args(mrb, "ii", &x, &y);
+
+  ptr = (struct cg_sprite *)DATA_PTR(self);
+  texture_v = mrb_iv_get(mrb, self, id_at_texture);
+  texture_ptr = (struct cg_texture *)DATA_PTR(texture_v);
+
+  dst_rect.x = x;
+  dst_rect.y = y;
+  dst_rect.w = ptr->rect.w;
+  dst_rect.h = ptr->rect.h;
+
+  SDL_RenderCopy(cg_core.renderer, texture_ptr->data, &ptr->rect, &dst_rect);
+
+  return self;
+}
+
+void
+cg_sprite_init(mrb_state *mrb)
+{
+  struct RClass *cg_m, *cg_cSprite;
+
+  id_at_texture = mrb_intern_lit(mrb, "@texture");
+
+  cg_m = mrb_module_get(mrb, "CandyGear");
+  cg_cSprite = mrb_define_class_under(mrb, cg_m, "Sprite", mrb->object_class);
+  MRB_SET_INSTANCE_TT(cg_cSprite, MRB_TT_DATA);
+  mrb_define_class_method(
+      mrb, cg_cSprite, "load_yaml", cg_cSrpite_load_yaml, MRB_ARGS_REQ(2));
+  mrb_define_method(
+      mrb, cg_cSprite, "initialize", cg_cSprite_initialize, MRB_ARGS_REQ(5));
+  mrb_define_method(
+      mrb, cg_cSprite, "texture", cg_cSprite_texture, MRB_ARGS_NONE());
+  mrb_define_method(
+    mrb, cg_cSprite, "width", cg_cSprite_width, MRB_ARGS_NONE());
+  mrb_define_method(
+    mrb, cg_cSprite, "height", cg_cSprite_height, MRB_ARGS_NONE());
+  mrb_define_method(
+      mrb, cg_cSprite, "draw", cg_cSprite_draw, MRB_ARGS_REQ(1));
+  mrb_define_method(
+      mrb, cg_cSprite, "draw_xy", cg_cSprite_draw_xy, MRB_ARGS_REQ(2));
+}
diff --git a/src/sprite.h b/src/sprite.h
new file mode 100644
index 0000000..7a85418
--- /dev/null
+++ b/src/sprite.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_SPRITE_H
+#define CANDY_GEAR_SPRITE_H 1
+
+#include "core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct cg_sprite
+{
+  SDL_Rect rect;
+};
+
+extern const struct mrb_data_type cg_sprite_type;
+
+void
+cg_sprite_init(mrb_state *mrb);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_SPRITE_H */
diff --git a/src/sprite_implementation.cpp b/src/sprite_implementation.cpp
new file mode 100644
index 0000000..4ba0edf
--- /dev/null
+++ b/src/sprite_implementation.cpp
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "sprite_implementation.h"
+
+#include <fstream>
+
+#include <yaml-cpp/yaml.h>
+
+SDL_bool
+cg_SpriteArray_constructor(
+  struct cg_SpriteArray_s *self, const char *file_path)
+{
+  YAML::Node root = YAML::LoadFile(file_path);
+  self->len = root.size();
+  self->sprites = new cg_Sprite_s[self->len];
+
+  int index = 0;
+  for(YAML::const_iterator sprite_node = root.begin();
+      sprite_node != root.end();
+      sprite_node++)
+  {
+    cg_Sprite_s *sprite = &self->sprites[index];
+
+    auto node_name = sprite_node->first.as<std::string>();
+    sprite->name = new char[node_name.size() + 1];
+    strcpy(sprite->name, node_name.c_str());
+
+    sprite->x = sprite_node->second["x"].as<int32_t>();
+    sprite->y = sprite_node->second["y"].as<int32_t>();
+    sprite->width = sprite_node->second["width"].as<int32_t>();
+    sprite->height = sprite_node->second["height"].as<int32_t>();
+
+    index++;
+  }
+
+  return SDL_TRUE;
+}
+
+void
+cg_SpriteArray_destructor(struct cg_SpriteArray_s *self)
+{
+  for(auto i = 0; i < self->len; i++) delete[] self->sprites[i].name;
+  delete[] self->sprites;
+}
diff --git a/src/sprite_implementation.h b/src/sprite_implementation.h
new file mode 100644
index 0000000..c421188
--- /dev/null
+++ b/src/sprite_implementation.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_SPRITE_IMPLEMENTATION_H
+#define CANDY_GEAR_SPRITE_IMPLEMENTATION_H 1
+
+#include <SDL2/SDL.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct cg_Sprite_s
+{
+  char *name;
+  int32_t x, y, width, height;
+};
+
+struct cg_SpriteArray_s
+{
+  int32_t len;
+  struct cg_Sprite_s *sprites;
+};
+
+SDL_bool
+cg_SpriteArray_constructor(
+  struct cg_SpriteArray_s *self, const char *file_path);
+
+void
+cg_SpriteArray_destructor(struct cg_SpriteArray_s *self);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_SPRITE_IMPLEMENTATION_H */
diff --git a/src/texture.c b/src/texture.c
new file mode 100644
index 0000000..f363c1f
--- /dev/null
+++ b/src/texture.c
@@ -0,0 +1,223 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "texture.h"
+
+#include "color.h"
+#include "core.h"
+#include "font.h"
+#include "palette.h"
+#include "pgm_image.h"
+#include "point.h"
+
+void
+cg_free_texture(mrb_state *mrb, void* obj)
+{
+  struct cg_texture *ptr = obj;
+
+  SDL_DestroyTexture(ptr->data);
+  mrb_free(mrb, ptr);
+}
+
+const struct mrb_data_type cg_texture_type = {
+  "CG_Texture", cg_free_texture };
+
+static mrb_value
+texture_alloc(mrb_state *mrb, mrb_value class)
+{
+  struct RClass *cg_cTexture = mrb_class_ptr(class);
+  enum mrb_vtype ttype = MRB_INSTANCE_TT(cg_cTexture);
+
+  // I do not know if I need this. If things break, try uncomment this line.
+  // if (ttype == 0) ttype = MRB_TT_OBJECT;
+  return mrb_obj_value(
+    (struct RObject*)mrb_obj_alloc(mrb, ttype, cg_cTexture));
+}
+
+static mrb_value
+cg_cTexture_from_image(mrb_state *mrb, mrb_value self)
+{
+  PGMImage pgm_img;
+
+  struct mrb_value texture = texture_alloc(mrb, self);
+  const char *file_path;
+  struct cg_palette *palette;
+  struct cg_texture *ptr;
+  mrb_bool palette_given;
+  SDL_Surface *surface = NULL;
+
+  mrb_get_args(
+    mrb, "z|d?", &file_path, &palette, &cg_palette_type, &palette_given);
+  ptr = (struct cg_texture *)DATA_PTR(texture);
+  if(ptr) mrb_free(mrb, ptr);
+  ptr = (struct cg_texture *)mrb_malloc(mrb, sizeof(struct cg_texture));
+  if(palette_given)
+  {
+    if(!PGMImage_constructor(&pgm_img, file_path))
+      mrb_raise(mrb, E_RUNTIME_ERROR, pgm_img.error);
+
+    // Depth = 8 bits image.
+    // Pitch = 1 byte (8 bits) * image width.
+    surface = SDL_CreateRGBSurfaceWithFormatFrom(
+      pgm_img.data, pgm_img.width, pgm_img.height, 8, pgm_img.width,
+      SDL_PIXELFORMAT_INDEX8);
+    if(!surface) mrb_raise(mrb, E_RUNTIME_ERROR, SDL_GetError());
+    SDL_SetPaletteColors(surface->format->palette, palette->colors, 0, 256);
+  }
+  else
+  {
+    surface = IMG_Load(file_path);
+    if(!surface) mrb_raise(mrb, E_RUNTIME_ERROR, IMG_GetError());
+  }
+
+  ptr->data = SDL_CreateTextureFromSurface(cg_core.renderer, surface);
+  SDL_SetTextureBlendMode(ptr->data, SDL_BLENDMODE_BLEND);
+  SDL_FreeSurface(surface);
+  if(palette_given) PGMImage_destructor(&pgm_img);
+  if(ptr->data == NULL) mrb_raise(mrb, E_RUNTIME_ERROR, SDL_GetError());
+
+  SDL_QueryTexture(ptr->data, NULL, NULL, &ptr->width, &ptr->height);
+
+  mrb_data_init(texture, ptr, &cg_texture_type);
+  return texture;
+}
+
+mrb_value
+cg_cText_from_text(mrb_state *mrb, mrb_value self)
+{
+  char *text;
+  SDL_Surface *surface = NULL;
+  mrb_bool background;
+  struct mrb_value texture = texture_alloc(mrb, self);
+  struct cg_color *tx_color_ptr, *bg_color_ptr;
+  struct cg_font *font_ptr;
+  struct cg_texture *ptr;
+
+  mrb_get_args(
+      mrb, "zdd|d?", &text, &font_ptr, &cg_font_type,
+      &tx_color_ptr, &cg_color_type, &bg_color_ptr, &cg_color_type,
+      &background);
+
+  ptr = (struct cg_texture *)DATA_PTR(texture);
+  if(ptr) mrb_free(mrb, ptr);
+  ptr = (struct cg_texture *)mrb_malloc(mrb, sizeof(struct cg_texture));
+
+  // Create surface.
+  if(background)
+    surface = TTF_RenderUTF8_Shaded(
+        font_ptr->data, text, tx_color_ptr->data, bg_color_ptr->data);
+  else
+    surface = TTF_RenderUTF8_Solid(font_ptr->data, text, tx_color_ptr->data);
+  if(surface == NULL) mrb_raise(mrb, E_RUNTIME_ERROR, TTF_GetError());
+
+  // Convert the surface to a texture.
+  ptr->data = SDL_CreateTextureFromSurface(cg_core.renderer, surface);
+  SDL_FreeSurface(surface);
+  if(ptr->data == NULL) mrb_raise(mrb, E_RUNTIME_ERROR, SDL_GetError());
+
+  SDL_QueryTexture(ptr->data, NULL, NULL, &ptr->width, &ptr->height);
+  mrb_data_init(texture, ptr, &cg_texture_type);
+  return texture;
+}
+
+static mrb_value
+cg_cTexture_width(mrb_state *mrb, mrb_value self)
+{
+  struct cg_texture *ptr;
+
+  ptr = (struct cg_texture *)DATA_PTR(self);
+
+  return mrb_int_value(mrb, ptr->width);
+}
+
+static mrb_value
+cg_cTexture_height(mrb_state *mrb, mrb_value self)
+{
+  struct cg_texture *ptr;
+
+  ptr = (struct cg_texture *)DATA_PTR(self);
+
+  return mrb_int_value(mrb, ptr->height);
+}
+
+static mrb_value
+cg_cTexture_draw(mrb_state *mrb, mrb_value self)
+{
+  SDL_Rect dst_rect;
+
+  struct cg_texture *ptr;
+  struct cg_point *point;
+
+  mrb_get_args(mrb, "d", &point, &cg_point_type);
+  ptr = (struct cg_texture *)DATA_PTR(self);
+
+  dst_rect.x = point->data.x;
+  dst_rect.y = point->data.y;
+  dst_rect.w = ptr->width;
+  dst_rect.h = ptr->height;
+
+  SDL_RenderCopy(cg_core.renderer, ptr->data, NULL, &dst_rect);
+
+  return self;
+}
+
+static mrb_value
+cg_cTexture_draw_xy(mrb_state *mrb, mrb_value self)
+{
+  SDL_Rect dst_rect;
+
+  struct cg_texture *ptr;
+  mrb_int x, y;
+
+  mrb_get_args(mrb, "ii", &x, &y);
+  ptr = (struct cg_texture *)DATA_PTR(self);
+
+  dst_rect.x = x;
+  dst_rect.y = y;
+  dst_rect.w = ptr->width;
+  dst_rect.h = ptr->height;
+
+  SDL_RenderCopy(cg_core.renderer, ptr->data, NULL, &dst_rect);
+
+  return self;
+}
+
+void
+cg_texture_init(mrb_state *mrb)
+{
+  struct RClass *cg_m, *cg_cTexture;
+
+  cg_m = mrb_module_get(mrb, "CandyGear");
+  cg_cTexture = mrb_define_class_under(
+    mrb, cg_m, "Texture", mrb->object_class);
+  MRB_SET_INSTANCE_TT(cg_cTexture, MRB_TT_DATA);
+
+  mrb_undef_class_method(mrb, cg_cTexture, "new");
+  mrb_define_class_method(
+    mrb, cg_cTexture, "from_image", cg_cTexture_from_image,
+    MRB_ARGS_REQ(1) | MRB_ARGS_OPT(1));
+  mrb_define_class_method(
+    mrb, cg_cTexture, "from_text", cg_cText_from_text,
+    MRB_ARGS_REQ(3)|MRB_ARGS_OPT(1));
+  mrb_define_method(
+    mrb, cg_cTexture, "width", cg_cTexture_width, MRB_ARGS_NONE());
+  mrb_define_method(
+    mrb, cg_cTexture, "height", cg_cTexture_height, MRB_ARGS_NONE());
+  mrb_define_method(
+    mrb, cg_cTexture, "draw", cg_cTexture_draw, MRB_ARGS_REQ(1));
+  mrb_define_method(
+    mrb, cg_cTexture, "draw_xy", cg_cTexture_draw_xy, MRB_ARGS_REQ(2));
+}
diff --git a/src/texture.h b/src/texture.h
new file mode 100644
index 0000000..f89542f
--- /dev/null
+++ b/src/texture.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2022 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_TEXTURE_H
+#define CANDY_GEAR_TEXTURE_H 1
+
+#include "core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct cg_texture
+{
+  SDL_Texture *data;
+  int width, height;
+};
+
+extern const struct mrb_data_type cg_texture_type;
+
+void
+cg_texture_init(mrb_state *mrb);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* CANDY_GEAR_TEXTURE_H */