add documentation and set functions

doc/CMakeLists.txt

@@ -0,0 +1,35 @@
+#[[**************************************************************************
+* libragephoto RAGE Photo Parser
+* Copyright (C) 2021 Syping
+*
+* Redistribution and use in source and binary forms, with or without modification,
+* are permitted provided that the following conditions are met:
+*
+* 1. Redistributions of source code must retain the above copyright notice,
+* this list of conditions and the following disclaimer.
+*
+* 2. Redistributions in binary form must reproduce the above copyright notice,
+* this list of conditions and the following disclaimer in the documentation
+* and/or other materials provided with the distribution.
+*
+* This software is provided as-is, no warranties are given to you, we are not
+* responsible for anything with use of the software, you are self responsible.
+****************************************************************************]]
+
+cmake_minimum_required(VERSION 3.7)
+find_package(Doxygen REQUIRED)
+include(GNUInstallDirs)
+
+if (NOT DOXYGEN_FOUND)
+    message(FATAL_ERROR "Doxygen is needed to build the documentation.")
+endif()
+
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/Doxyfile.in ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile @ONLY)
+add_custom_target(
+    doc ALL
+    COMMAND ${DOXYGEN_EXECUTABLE} ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile
+    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+    COMMENT "Generate API documentation with Doxygen"
+    VERBATIM
+)
+install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/html DESTINATION ${CMAKE_INSTALL_DOCDIR})

doc/Doxyfile.in

@@ -0,0 +1,10 @@
+PROJECT_NAME           = "libragephoto"
+PROJECT_NUMBER         = "Version: @PROJECT_VERSION@"
+INPUT                  = "@CMAKE_CURRENT_SOURCE_DIR@/index.doc" \
+                         "src"
+OUTPUT_DIRECTORY       = "@CMAKE_CURRENT_BINARY_DIR@"
+EXTRACT_PRIVATE        = NO
+ENABLE_PREPROCESSING   = YES
+MACRO_EXPANSION        = YES
+EXPAND_ONLY_PREDEF     = YES
+PREDEFINED             = protected=private