initial commit

CMakeLists.txt

@@ -0,0 +1,72 @@
+project(fpng_test)
+
+cmake_minimum_required(VERSION 3.0)
+option(BUILD_X64 "build 64-bit" TRUE)
+
+message("Initial BUILD_X64=${BUILD_X64}")
+
+if( NOT CMAKE_BUILD_TYPE )
+  set( CMAKE_BUILD_TYPE Release )
+endif()
+
+message( ${PROJECT_NAME} " build type: " ${CMAKE_BUILD_TYPE} )
+
+if (BUILD_X64)
+	message("Building 64-bit")
+else()
+	message("Building 32-bit")
+endif()
+
+if (NOT MSVC)
+   set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -g")
+   set(CMAKE_C_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -g")
+
+   set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE}")
+   set(CMAKE_C_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE}")
+
+   set(CMAKE_CXX_FLAGS -std=c++11)
+   set(GCC_COMPILE_FLAGS "-fvisibility=hidden -fPIC -fno-strict-aliasing -D_LARGEFILE64_SOURCE=1 -D_FILE_OFFSET_BITS=64 -Wall -Wextra")
+
+   if (NOT BUILD_X64)
+	  set(GCC_COMPILE_FLAGS "${GCC_COMPILE_FLAGS} -m32")
+   endif()
+
+   set(CMAKE_C_FLAGS  "${CMAKE_C_FLAGS}")
+   set(CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS}")
+
+   set(CMAKE_EXE_LINKER_FLAGS  "${CMAKE_EXE_LINKER_FLAGS} ${GCC_LINK_FLAGS} -Wl,-rpath .")
+
+   set(CMAKE_C_FLAGS  "${CMAKE_C_FLAGS} ${GCC_COMPILE_FLAGS}")
+   set(CMAKE_C_FLAGS_RELEASE  "${CMAKE_C_FLAGS_RELEASE} ${GCC_COMPILE_FLAGS}")
+   set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} ${GCC_COMPILE_FLAGS} -D_DEBUG")
+
+   set(CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} ${GCC_COMPILE_FLAGS}")
+   set(CMAKE_CXX_FLAGS_RELEASE  "${CMAKE_CXX_FLAGS_RELEASE} ${GCC_COMPILE_FLAGS}")
+   set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} ${GCC_COMPILE_FLAGS} -D_DEBUG")
+else()
+	set(CMAKE_C_FLAGS  "${CMAKE_C_FLAGS}")
+	set(CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS}")
+endif()
+
+set(FPNG_SRC_LIST ${COMMON_SRC_LIST} 
+	fpng.cpp
+	Crc32.cpp
+	fpng_test.cpp
+	lodepng.cpp
+	)
+
+if (APPLE)
+   set(BIN_DIRECTORY "bin_osx")
+else()
+   set(BIN_DIRECTORY "bin")
+endif()
+
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/${BIN_DIRECTORY})
+
+add_executable(fpng_test ${FPNG_SRC_LIST})
+
+if (NOT MSVC)
+   target_link_libraries(fpng_test m pthread)
+endif()
+
+install(TARGETS fpng_test DESTINATION bin)

Crc32.h

@@ -0,0 +1,69 @@
+// //////////////////////////////////////////////////////////
+// Crc32.h
+// Copyright (c) 2011-2019 Stephan Brumme. All rights reserved.
+// Slicing-by-16 contributed by Bulat Ziganshin
+// Tableless bytewise CRC contributed by Hagai Gold
+// see http://create.stephan-brumme.com/disclaimer.html
+//
+
+// if running on an embedded system, you might consider shrinking the
+// big Crc32Lookup table by undefining these lines:
+//#define CRC32_USE_LOOKUP_TABLE_BYTE
+//#define CRC32_USE_LOOKUP_TABLE_SLICING_BY_4
+#define CRC32_USE_LOOKUP_TABLE_SLICING_BY_8
+//#define CRC32_USE_LOOKUP_TABLE_SLICING_BY_16
+// - crc32_bitwise  doesn't need it at all
+// - crc32_halfbyte has its own small lookup table
+// - crc32_1byte_tableless and crc32_1byte_tableless2 don't need it at all
+// - crc32_1byte    needs only Crc32Lookup[0]
+// - crc32_4bytes   needs only Crc32Lookup[0..3]
+// - crc32_8bytes   needs only Crc32Lookup[0..7]
+// - crc32_4x8bytes needs only Crc32Lookup[0..7]
+// - crc32_16bytes  needs all of Crc32Lookup
+// using the aforementioned #defines the table is automatically fitted to your needs
+
+// uint8_t, uint32_t, int32_t
+#include <stdint.h>
+// size_t
+#include <cstddef>
+
+// crc32_fast selects the fastest algorithm depending on flags (CRC32_USE_LOOKUP_...)
+/// compute CRC32 using the fastest algorithm for large datasets on modern CPUs
+uint32_t crc32_fast    (const void* data, size_t length, uint32_t previousCrc32 = 0);
+
+/// merge two CRC32 such that result = crc32(dataB, lengthB, crc32(dataA, lengthA))
+uint32_t crc32_combine (uint32_t crcA, uint32_t crcB, size_t lengthB);
+
+/// compute CRC32 (bitwise algorithm)
+uint32_t crc32_bitwise (const void* data, size_t length, uint32_t previousCrc32 = 0);
+/// compute CRC32 (half-byte algoritm)
+uint32_t crc32_halfbyte(const void* data, size_t length, uint32_t previousCrc32 = 0);
+
+#ifdef CRC32_USE_LOOKUP_TABLE_BYTE
+/// compute CRC32 (standard algorithm)
+uint32_t crc32_1byte   (const void* data, size_t length, uint32_t previousCrc32 = 0);
+#endif
+
+/// compute CRC32 (byte algorithm) without lookup tables
+uint32_t crc32_1byte_tableless (const void* data, size_t length, uint32_t previousCrc32 = 0);
+/// compute CRC32 (byte algorithm) without lookup tables
+uint32_t crc32_1byte_tableless2(const void* data, size_t length, uint32_t previousCrc32 = 0);
+
+#ifdef CRC32_USE_LOOKUP_TABLE_SLICING_BY_4
+/// compute CRC32 (Slicing-by-4 algorithm)
+uint32_t crc32_4bytes  (const void* data, size_t length, uint32_t previousCrc32 = 0);
+#endif
+
+#ifdef CRC32_USE_LOOKUP_TABLE_SLICING_BY_8
+/// compute CRC32 (Slicing-by-8 algorithm)
+uint32_t crc32_8bytes  (const void* data, size_t length, uint32_t previousCrc32 = 0);
+/// compute CRC32 (Slicing-by-8 algorithm), unroll inner loop 4 times
+uint32_t crc32_4x8bytes(const void* data, size_t length, uint32_t previousCrc32 = 0);
+#endif
+
+#ifdef CRC32_USE_LOOKUP_TABLE_SLICING_BY_16
+/// compute CRC32 (Slicing-by-16 algorithm)
+uint32_t crc32_16bytes (const void* data, size_t length, uint32_t previousCrc32 = 0);
+/// compute CRC32 (Slicing-by-16 algorithm, prefetch upcoming data blocks)
+uint32_t crc32_16bytes_prefetch(const void* data, size_t length, uint32_t previousCrc32 = 0, size_t prefetchAhead = 256);
+#endif

fpng.h

@@ -0,0 +1,16 @@
+// fpng.h - R. Geldreich, Jr. - public domain or zlib license (see end of fpng.cpp for Public Domain waiver/optional license)
+#pragma once
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <vector>
+
+namespace fpng
+{
+	bool fpng_encode_image_to_memory(const void* pImage, int w, int h, int num_chans, bool flip, std::vector<uint8_t>& out_buf);
+
+#ifndef FPNG_NO_STDIO
+	bool fpng_encode_image_to_file(const char* pFilename, const void* pImage, int w, int h, int num_chans, bool flip);
+#endif
+
+} // namespace fpng

fpng.sln

@@ -0,0 +1,31 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.31911.196
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "fpng", "fpng.vcxproj", "{33211B65-F564-4E23-A640-FA7F02007CB3}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|x64 = Debug|x64
+		Debug|x86 = Debug|x86
+		Release|x64 = Release|x64
+		Release|x86 = Release|x86
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{33211B65-F564-4E23-A640-FA7F02007CB3}.Debug|x64.ActiveCfg = Debug|x64
+		{33211B65-F564-4E23-A640-FA7F02007CB3}.Debug|x64.Build.0 = Debug|x64
+		{33211B65-F564-4E23-A640-FA7F02007CB3}.Debug|x86.ActiveCfg = Debug|Win32
+		{33211B65-F564-4E23-A640-FA7F02007CB3}.Debug|x86.Build.0 = Debug|Win32
+		{33211B65-F564-4E23-A640-FA7F02007CB3}.Release|x64.ActiveCfg = Release|x64
+		{33211B65-F564-4E23-A640-FA7F02007CB3}.Release|x64.Build.0 = Release|x64
+		{33211B65-F564-4E23-A640-FA7F02007CB3}.Release|x86.ActiveCfg = Release|Win32
+		{33211B65-F564-4E23-A640-FA7F02007CB3}.Release|x86.Build.0 = Release|Win32
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {4225CF7B-633D-443D-A767-C66A2D22BCDA}
+	EndGlobalSection
+EndGlobal

fpng.vcxproj

@@ -0,0 +1,162 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|x64">
+      <Configuration>Debug</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|x64">
+      <Configuration>Release</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <VCProjectVersion>16.0</VCProjectVersion>
+    <Keyword>Win32Proj</Keyword>
+    <ProjectGuid>{33211b65-f564-4e23-a640-fa7f02007cb3}</ProjectGuid>
+    <RootNamespace>fpng</RootNamespace>
+    <WindowsTargetPlatformVersion>10.0</WindowsTargetPlatformVersion>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>v142</PlatformToolset>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <PlatformToolset>v142</PlatformToolset>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>v142</PlatformToolset>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <PlatformToolset>v142</PlatformToolset>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="Shared">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+    <OutDir>bin</OutDir>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <OutDir>bin</OutDir>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <LinkIncremental>true</LinkIncremental>
+    <OutDir>.\bin</OutDir>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <LinkIncremental>false</LinkIncremental>
+    <OutDir>bin</OutDir>
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
+      <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ConformanceMode>true</ConformanceMode>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <WarningLevel>Level3</WarningLevel>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <SDLCheck>true</SDLCheck>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ConformanceMode>true</ConformanceMode>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <ClCompile>
+      <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
+      <PreprocessorDefinitions>_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ConformanceMode>true</ConformanceMode>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <ClCompile>
+      <WarningLevel>Level3</WarningLevel>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <SDLCheck>true</SDLCheck>
+      <PreprocessorDefinitions>NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ConformanceMode>true</ConformanceMode>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemGroup>
+    <ClCompile Include="Crc32.cpp" />
+    <ClCompile Include="fpng.cpp" />
+    <ClCompile Include="fpng_test.cpp" />
+    <ClCompile Include="lodepng.cpp" />
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="Crc32.h" />
+    <ClInclude Include="fpng.h" />
+    <ClInclude Include="lodepng.h" />
+    <ClInclude Include="qoi.h" />
+    <ClInclude Include="stb_image.h" />
+    <ClInclude Include="stb_image_write.h" />
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>

fpng.vcxproj.filters

@@ -0,0 +1,51 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <Filter Include="Source Files">
+      <UniqueIdentifier>{4FC737F1-C7A5-4376-A066-2A32D752A2FF}</UniqueIdentifier>
+      <Extensions>cpp;c;cc;cxx;c++;cppm;ixx;def;odl;idl;hpj;bat;asm;asmx</Extensions>
+    </Filter>
+    <Filter Include="Header Files">
+      <UniqueIdentifier>{93995380-89BD-4b04-88EB-625FBE52EBFB}</UniqueIdentifier>
+      <Extensions>h;hh;hpp;hxx;h++;hm;inl;inc;ipp;xsd</Extensions>
+    </Filter>
+    <Filter Include="Resource Files">
+      <UniqueIdentifier>{67DA6AB6-F800-4c08-8B7A-83BB121AAD01}</UniqueIdentifier>
+      <Extensions>rc;ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe;resx;tiff;tif;png;wav;mfcribbon-ms</Extensions>
+    </Filter>
+  </ItemGroup>
+  <ItemGroup>
+    <ClCompile Include="fpng.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="Crc32.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="fpng_test.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="lodepng.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="Crc32.h">
+      <Filter>Source Files</Filter>
+    </ClInclude>
+    <ClInclude Include="fpng.h">
+      <Filter>Source Files</Filter>
+    </ClInclude>
+    <ClInclude Include="qoi.h">
+      <Filter>Source Files</Filter>
+    </ClInclude>
+    <ClInclude Include="stb_image.h">
+      <Filter>Source Files</Filter>
+    </ClInclude>
+    <ClInclude Include="stb_image_write.h">
+      <Filter>Source Files</Filter>
+    </ClInclude>
+    <ClInclude Include="lodepng.h">
+      <Filter>Source Files</Filter>
+    </ClInclude>
+  </ItemGroup>
+</Project>

fpng_test.cpp

@@ -0,0 +1,532 @@
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+
+#if defined(_WIN32)
+// For QueryPerformanceCounter/QueryPerformanceFrequency
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#endif
+
+#include "fpng.h"
+#include "lodepng.h"
+
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb_image.h"
+
+#define STB_IMAGE_WRITE_IMPLEMENTATION
+#include "stb_image_write.h"
+
+#define QOI_IMPLEMENTATION
+#include "qoi.h"
+
+typedef std::vector<uint8_t> uint8_vec;
+
+typedef uint64_t timer_ticks;
+
+template <typename S> static inline S maximum(S a, S b) { return (a > b) ? a : b; }
+template <typename S> static inline S minimum(S a, S b) { return (a < b) ? a : b; }
+
+class interval_timer
+{
+public:
+	interval_timer();
+
+	void start();
+	void stop();
+
+	double get_elapsed_secs() const;
+	inline double get_elapsed_ms() const { return 1000.0f * get_elapsed_secs(); }
+
+	static void init();
+	static inline timer_ticks get_ticks_per_sec() { return g_freq; }
+	static timer_ticks get_ticks();
+	static double ticks_to_secs(timer_ticks ticks);
+	static inline double ticks_to_ms(timer_ticks ticks) { return ticks_to_secs(ticks) * 1000.0f; }
+
+private:
+	static timer_ticks g_init_ticks, g_freq;
+	static double g_timer_freq;
+
+	timer_ticks m_start_time, m_stop_time;
+
+	bool m_started, m_stopped;
+};
+
+timer_ticks interval_timer::g_init_ticks, interval_timer::g_freq;
+double interval_timer::g_timer_freq;
+
+#if defined(_WIN32)
+inline void query_counter(timer_ticks* pTicks)
+{
+	QueryPerformanceCounter(reinterpret_cast<LARGE_INTEGER*>(pTicks));
+}
+inline void query_counter_frequency(timer_ticks* pTicks)
+{
+	QueryPerformanceFrequency(reinterpret_cast<LARGE_INTEGER*>(pTicks));
+}
+#elif defined(__APPLE__)
+#include <sys/time.h>
+inline void query_counter(timer_ticks* pTicks)
+{
+	struct timeval cur_time;
+	gettimeofday(&cur_time, NULL);
+	*pTicks = static_cast<unsigned long long>(cur_time.tv_sec) * 1000000ULL + static_cast<unsigned long long>(cur_time.tv_usec);
+}
+inline void query_counter_frequency(timer_ticks* pTicks)
+{
+	*pTicks = 1000000;
+}
+#elif defined(__GNUC__)
+#include <sys/timex.h>
+inline void query_counter(timer_ticks* pTicks)
+{
+	struct timeval cur_time;
+	gettimeofday(&cur_time, NULL);
+	*pTicks = static_cast<unsigned long long>(cur_time.tv_sec) * 1000000ULL + static_cast<unsigned long long>(cur_time.tv_usec);
+}
+inline void query_counter_frequency(timer_ticks* pTicks)
+{
+	*pTicks = 1000000;
+}
+#else
+#error TODO
+#endif
+
+interval_timer::interval_timer() : m_start_time(0), m_stop_time(0), m_started(false), m_stopped(false)
+{
+	if (!g_timer_freq)
+		init();
+}
+
+void interval_timer::start()
+{
+	query_counter(&m_start_time);
+	m_started = true;
+	m_stopped = false;
+}
+
+void interval_timer::stop()
+{
+	assert(m_started);
+	query_counter(&m_stop_time);
+	m_stopped = true;
+}
+
+double interval_timer::get_elapsed_secs() const
+{
+	assert(m_started);
+	if (!m_started)
+		return 0;
+
+	timer_ticks stop_time = m_stop_time;
+	if (!m_stopped)
+		query_counter(&stop_time);
+
+	timer_ticks delta = stop_time - m_start_time;
+	return delta * g_timer_freq;
+}
+
+void interval_timer::init()
+{
+	if (!g_timer_freq)
+	{
+		query_counter_frequency(&g_freq);
+		g_timer_freq = 1.0f / g_freq;
+		query_counter(&g_init_ticks);
+	}
+}
+
+timer_ticks interval_timer::get_ticks()
+{
+	if (!g_timer_freq)
+		init();
+	timer_ticks ticks;
+	query_counter(&ticks);
+	return ticks - g_init_ticks;
+}
+
+double interval_timer::ticks_to_secs(timer_ticks ticks)
+{
+	if (!g_timer_freq)
+		init();
+	return ticks * g_timer_freq;
+}
+
+bool read_file_to_vec(const char* pFilename, uint8_vec& data)
+{
+	FILE* pFile = nullptr;
+#ifdef _WIN32
+	fopen_s(&pFile, pFilename, "rb");
+#else
+	pFile = fopen(pFilename, "rb");
+#endif
+	if (!pFile)
+		return false;
+
+	fseek(pFile, 0, SEEK_END);
+#ifdef _WIN32
+	int64_t filesize = _ftelli64(pFile);
+#else
+	int64_t filesize = ftello(pFile);
+#endif
+	if (filesize < 0)
+	{
+		fclose(pFile);
+		return false;
+	}
+	fseek(pFile, 0, SEEK_SET);
+
+	if (sizeof(size_t) == sizeof(uint32_t))
+	{
+		if (filesize > 0x70000000)
+		{
+			// File might be too big to load safely in one alloc
+			fclose(pFile);
+			return false;
+		}
+	}
+
+	data.resize((size_t)filesize);
+
+	if (filesize)
+	{
+		if (fread(&data[0], 1, (size_t)filesize, pFile) != (size_t)filesize)
+		{
+			fclose(pFile);
+			return false;
+		}
+	}
+
+	fclose(pFile);
+	return true;
+}
+
+bool write_data_to_file_internal(const char* pFilename, const void* pData, size_t len)
+{
+	FILE* pFile = nullptr;
+#ifdef _WIN32
+	fopen_s(&pFile, pFilename, "wb");
+#else
+	pFile = fopen(pFilename, "wb");
+#endif
+	if (!pFile)
+		return false;
+
+	if (len)
+	{
+		if (fwrite(pData, 1, len, pFile) != len)
+		{
+			fclose(pFile);
+			return false;
+		}
+	}
+
+	return fclose(pFile) != EOF;
+}
+
+bool write_data_to_file(const char* pFilename, const void* pData, size_t len)
+{
+#ifdef _WIN32
+	const uint32_t MAX_TRIES = 10;
+#else
+	const uint32_t MAX_TRIES = 1;
+#endif
+
+	for (uint32_t i = 0; i < MAX_TRIES; i++)
+	{
+		if (write_data_to_file_internal(pFilename, pData, len))
+			return true;
+#ifdef _WIN32
+		Sleep(100);
+#endif
+	}
+	return false;
+}
+
+struct color_rgba
+{
+	uint8_t m_c[4];
+};
+
+static void write_func_stbi(void* context, void* data, int size)
+{
+	if (!size)
+		return;
+
+	uint8_vec* pVec = (uint8_vec*)context;
+
+	size_t cur_s = pVec->size();
+	pVec->resize(cur_s + size);
+	memcpy(pVec->data() + cur_s, data, size);
+}
+
+int main(int arg_c, char **arg_v)
+{
+	if (arg_c < 2)
+	{
+		printf("Usage: fpng_test filename\n");
+		return EXIT_FAILURE;
+	}
+
+	const char* pFilename = nullptr;
+	bool csv_flag = false;
+	for (int i = 1; i < arg_c; i++)
+	{
+		const char* pArg = arg_v[i];
+		if (pArg[0] == '-')
+		{
+			if (pArg[1] == 'c')
+			{
+				csv_flag = true;
+			}
+			else
+			{
+				fprintf(stderr, "Recognized option: %s\n", pArg);
+				return EXIT_FAILURE;
+			}
+		}
+		else
+		{
+			if (pFilename)
+			{
+				fprintf(stderr, "Too many filenames: %s\n", pArg);
+				return EXIT_FAILURE;
+			}
+			pFilename = pArg;
+		}
+	}
+
+	if (!csv_flag)
+		printf("Filename: %s\n", pFilename);
+
+	uint8_vec source_file_data;
+	if (!read_file_to_vec(pFilename, source_file_data))
+	{
+		fprintf(stderr, "Failed reading source file data \"%s\"\n", pFilename);
+		return EXIT_FAILURE;
+	}
+
+	unsigned int source_width = 0, source_height = 0;
+	unsigned char* pSource_image_buffer = nullptr;
+	unsigned error = lodepng_decode_memory(&pSource_image_buffer, &source_width, &source_height, source_file_data.data(), source_file_data.size(), LCT_RGBA, 8);
+	if (error != 0)
+	{
+		fprintf(stderr, "Failed unpacking source file \"%s\"\n", pFilename);
+		return EXIT_FAILURE;
+	}
+
+	const color_rgba* pSource_pixels32 = (const color_rgba*)pSource_image_buffer;
+	uint32_t total_source_pixels = source_width * source_height;
+	bool has_alpha = false;
+	for (uint32_t i = 0; i < total_source_pixels; i++)
+	{
+		if (pSource_pixels32[i].m_c[3] < 255)
+		{
+			has_alpha = true;
+			break;
+		}
+	}
+
+	const uint32_t source_chans = has_alpha ? 4 : 3;
+
+	if (!csv_flag)
+		printf("Dimensions: %ux%u, Has Alpha: %u, Total Pixels: %u, bytes: %u (%f MB)\n", source_width, source_height, has_alpha, total_source_pixels, total_source_pixels * source_chans, total_source_pixels * source_chans / (1024.0f * 1024.0f));
+
+	uint8_vec source_image_buffer24(total_source_pixels * 3);
+	for (uint32_t i = 0; i < total_source_pixels; i++)
+	{
+		source_image_buffer24[i * 3 + 0] = pSource_pixels32[i].m_c[0];
+		source_image_buffer24[i * 3 + 1] = pSource_pixels32[i].m_c[1];
+		source_image_buffer24[i * 3 + 2] = pSource_pixels32[i].m_c[2];
+	}
+
+	const uint8_t* pSource_pixels24 = source_image_buffer24.data();
+
+	const uint32_t NUM_TIMES_TO_ENCODE = 3;
+	interval_timer tm;
+
+	// FPNG
+
+	std::vector<uint8_t> fpng_file_buf;
+	double fpng_best_time = 1e+9f;
+	for (uint32_t i = 0; i < NUM_TIMES_TO_ENCODE; i++)
+	{
+		tm.start();
+		if (!fpng::fpng_encode_image_to_memory((source_chans == 3) ? (const void *)pSource_pixels24 : (const void*)pSource_pixels32, source_width, source_height, source_chans, false, fpng_file_buf))
+		{
+			fprintf(stderr, "fpng_encode_image_to_memory() failed!\n");
+			return EXIT_FAILURE;
+		}
+		fpng_best_time = minimum(fpng_best_time, tm.get_elapsed_secs());
+	}
+
+	if (!csv_flag)
+		printf("FPNG: %f secs, %u bytes, %f MB\n", fpng_best_time, (uint32_t)fpng_file_buf.size(), fpng_file_buf.size() / (1024.0f * 1024.0f));
+
+	if (!write_data_to_file("fpng.png", fpng_file_buf.data(), fpng_file_buf.size()))
+	{
+		fprintf(stderr, "Failed writing to file fpng.png\n");
+		return EXIT_FAILURE;
+	}
+
+	// Verify FPNG's output data using lodepng
+	{
+		unsigned int lodepng_decoded_w = 0, lodepng_decoded_h = 0;
+		unsigned char* lodepng_decoded_buffer = nullptr;
+		error = lodepng_decode_memory(&lodepng_decoded_buffer, &lodepng_decoded_w, &lodepng_decoded_h, (unsigned char*)fpng_file_buf.data(), fpng_file_buf.size(), LCT_RGBA, 8);
+		if (error != 0)
+		{
+			fprintf(stderr, "lodepng failed decompressing FPNG's output PNG file!\n");
+			return EXIT_FAILURE;
+		}
+
+		if (memcmp(lodepng_decoded_buffer, pSource_pixels32, total_source_pixels * 4) != 0)
+		{
+			fprintf(stderr, "FPNG decode verification failed (using lodepng)!\n");
+			return EXIT_FAILURE;
+		}
+		free(lodepng_decoded_buffer);
+	}
+
+	// Verify FPNG's output data using stb_image.h
+	{
+		int x, y, c;
+		void* p = stbi_load_from_memory(fpng_file_buf.data(), (int)fpng_file_buf.size(), &x, &y, &c, 4);
+		if (!p)
+		{
+			fprintf(stderr, "stb_image.h failed decompressing FPNG's output PNG file!\n");
+			return EXIT_FAILURE;
+		}
+
+		if (memcmp(p, pSource_pixels32, total_source_pixels * 4) != 0)
+		{
+			fprintf(stderr, "FPNG decode verification failed (using stb_image.h)!\n");
+			return EXIT_FAILURE;
+		}
+		free(p);
+	}
+
+	// lodepng
+
+	uint8_vec lodepng_file_buf;
+	double lodepng_best_time = 1e+9f;
+
+	for (uint32_t i = 0; i < NUM_TIMES_TO_ENCODE; i++)
+	{
+		tm.start();
+		lodepng_file_buf.resize(0);
+		error = lodepng::encode(lodepng_file_buf, pSource_image_buffer, source_width, source_height, LCT_RGBA, 8);
+		lodepng_best_time = minimum(lodepng_best_time, tm.get_elapsed_secs());
+
+		if (error != 0)
+		{
+			fprintf(stderr, "lodepng::encode() failed!\n");
+			return EXIT_FAILURE;
+		}
+	}
+	
+	if (!csv_flag)
+		printf("lodepng: %f secs, %u bytes, %f MB\n", lodepng_best_time, (uint32_t)lodepng_file_buf.size(), (double)lodepng_file_buf.size() / (1024.0f * 1024.0f));
+
+	if (!write_data_to_file("lodepng.png", lodepng_file_buf.data(), lodepng_file_buf.size()))
+	{
+		fprintf(stderr, "Failed writing to file lodepng.png\n");
+		return EXIT_FAILURE;
+	}
+
+	// stb_image_write.h
+	uint8_vec stbi_file_buf;
+	stbi_file_buf.reserve(total_source_pixels * source_chans);
+	double stbi_best_time = 1e+9f;
+	
+	for (uint32_t i = 0; i < NUM_TIMES_TO_ENCODE; i++)
+	{
+		stbi_file_buf.resize(0);
+
+		tm.start();
+		
+		int res = stbi_write_png_to_func(write_func_stbi, &stbi_file_buf, source_width, source_height, source_chans, (source_chans == 3) ? (void *)pSource_pixels24 : (void*)pSource_pixels32, source_width * source_chans);
+		if (!res)
+		{
+			fprintf(stderr, "stbi_write_png_to_func() failed!\n");
+			return EXIT_FAILURE;
+		}
+
+		stbi_best_time = minimum(stbi_best_time, tm.get_elapsed_secs());
+	}
+
+	if (!csv_flag)
+		printf("stbi: %f secs, %u bytes, %f MB\n", stbi_best_time, (uint32_t)stbi_file_buf.size(), (double)stbi_file_buf.size() / (1024.0f * 1024.0f));
+
+	if (!write_data_to_file("stbi.png", stbi_file_buf.data(), stbi_file_buf.size()))
+	{
+		fprintf(stderr, "Failed writing to file stbi.png\n");
+		return EXIT_FAILURE;
+	}
+
+	// QOI
+	qoi_desc qdesc;
+	qdesc.channels = source_chans;
+	qdesc.width = source_width;
+	qdesc.height = source_height;
+	qdesc.colorspace = QOI_SRGB;
+
+	int qoi_len = 0;
+	
+	void* pQOI_data = nullptr;
+	double qoi_best_time = 1e+9f;
+	for (uint32_t i = 0; i < NUM_TIMES_TO_ENCODE; i++)
+	{
+		if (pQOI_data)
+			free(pQOI_data);
+
+		tm.start();
+
+		pQOI_data = qoi_encode((source_chans == 4) ? (void*)pSource_pixels32 : (void*)pSource_pixels24, &qdesc, &qoi_len);
+		
+		qoi_best_time = minimum(qoi_best_time, tm.get_elapsed_secs());
+	}
+
+	if (!write_data_to_file("qoi.qoi", pQOI_data, qoi_len))
+	{
+		fprintf(stderr, "Failed writing to file qoi.qoi\n");
+		return EXIT_FAILURE;
+	}
+
+	if (!csv_flag)
+		printf("qoi: %f secs, %i bytes, %f MB\n", qoi_best_time, qoi_len, (double)qoi_len / (1024.0f * 1024.0f));
+		
+	// Validate QOI's output file
+	{
+		qoi_desc qddesc;
+		void* pQOI_decomp_data = qoi_decode(pQOI_data, qoi_len, &qddesc, 4);
+
+		if (memcmp(pQOI_decomp_data, pSource_pixels32, total_source_pixels * 4) != 0)
+		{
+			fprintf(stderr, "QOI verification failure!\n");
+			return EXIT_FAILURE;
+		}
+		free(pQOI_decomp_data);
+		pQOI_decomp_data = nullptr;
+	}
+
+	if (csv_flag)
+	{
+		const double MB = 1024.0f * 1024.0f;
+
+		printf("%s, %u, %u, %u,    %f, %u, %f,   %f, %u, %f,   %f, %u, %f,   %f, %u, %f\n",
+			pFilename, source_width, source_height, source_chans,
+			qoi_best_time, (uint32_t)qoi_len, (double)qoi_len / MB,
+			fpng_best_time, (uint32_t)fpng_file_buf.size(), (double)fpng_file_buf.size() / MB,
+			lodepng_best_time, (uint32_t)lodepng_file_buf.size(), (double)lodepng_file_buf.size() / MB,
+			stbi_best_time, (uint32_t)stbi_file_buf.size(), (double)stbi_file_buf.size() / MB
+			);
+	}
+
+	return EXIT_SUCCESS;
+}
+

qoi.h

@@ -0,0 +1,656 @@
+/*
+
+QOI - The "Quite OK Image" format for fast, lossless image compression
+
+Dominic Szablewski - https://phoboslab.org
+
+
+-- LICENSE: The MIT License(MIT)
+
+Copyright(c) 2021 Dominic Szablewski
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files(the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and / or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions :
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+
+-- About
+
+QOI encodes and decodes images in a lossless format. An encoded QOI image is
+usually around 10--30% larger than a decently optimized PNG image.
+
+QOI outperforms simpler PNG encoders in compression ratio and performance. QOI
+images are typically 20% smaller than PNGs written with stbi_image. Encoding is 
+25-50x faster and decoding is 3-4x faster than stbi_image or libpng.
+
+
+-- Synopsis
+
+// Define `QOI_IMPLEMENTATION` in *one* C/C++ file before including this
+// library to create the implementation.
+
+#define QOI_IMPLEMENTATION
+#include "qoi.h"
+
+// Encode and store an RGBA buffer to the file system. The qoi_desc describes
+// the input pixel data.
+qoi_write("image_new.qoi", rgba_pixels, &(qoi_desc){
+	.width = 1920,
+	.height = 1080, 
+	.channels = 4,
+	.colorspace = QOI_SRGB
+});
+
+// Load and decode a QOI image from the file system into a 32bbp RGBA buffer.
+// The qoi_desc struct will be filled with the width, height, number of channels
+// and colorspace read from the file header.
+qoi_desc desc;
+void *rgba_pixels = qoi_read("image.qoi", &desc, 4);
+
+
+
+-- Documentation
+
+This library provides the following functions;
+- qoi_read    -- read and decode a QOI file
+- qoi_decode  -- decode the raw bytes of a QOI image from memory
+- qoi_write   -- encode and write a QOI file
+- qoi_encode  -- encode an rgba buffer into a QOI image in memory
+
+See the function declaration below for the signature and more information.
+
+If you don't want/need the qoi_read and qoi_write functions, you can define
+QOI_NO_STDIO before including this library.
+
+This library uses malloc() and free(). To supply your own malloc implementation
+you can define QOI_MALLOC and QOI_FREE before including this library.
+
+This library uses memset() to zero-initialize the index. To supply your own 
+implementation you can define QOI_ZEROARR before including this library.
+
+
+-- Data Format
+
+A QOI file has a 14 byte header, followed by any number of data "chunks" and 8
+zero-bytes to mark the end of the data stream.
+
+struct qoi_header_t {
+	char     magic[4];   // magic bytes "qoif"
+	uint32_t width;      // image width in pixels (BE)
+	uint32_t height;     // image height in pixels (BE)
+	uint8_t  channels;   // 3 = RGB, 4 = RGBA
+	uint8_t  colorspace; // 0 = sRGB with linear alpha, 1 = all channels linear
+};
+
+The decoder and encoder start with {r: 0, g: 0, b: 0, a: 255} as the previous
+pixel value. Pixels are either encoded as
+ - a run of the previous pixel
+ - an index into an array of previously seen pixels
+ - a difference to the previous pixel value in r,g,b
+ - full r,g,b or r,g,b,a values
+
+The color channels are assumed to not be premultiplied with the alpha channel 
+("un-premultiplied alpha").
+
+A running array[64] (zero-initialized) of previously seen pixel values is 
+maintained by the encoder and decoder. Each pixel that is seen by the encoder
+and decoder is put into this array at the position formed by a hash function of
+the color value. In the encoder, if the pixel value at the index matches the
+current pixel, this index position is written to the stream as QOI_OP_INDEX. 
+The hash function for the index is:
+
+	index_position = (r * 3 + g * 5 + b * 7 + a * 11) % 64
+
+Each chunk starts with a 2- or 8-bit tag, followed by a number of data bits. The 
+bit length of chunks is divisible by 8 - i.e. all chunks are byte aligned. All 
+values encoded in these data bits have the most significant bit on the left.
+
+The 8-bit tags have precedence over the 2-bit tags. A decoder must check for the
+presence of an 8-bit tag first.
+
+The byte stream is padded with 8 zero-bytes at the end.
+
+
+The possible chunks are:
+
+
+.- QOI_OP_INDEX ----------.
+|         Byte[0]         |
+|  7  6  5  4  3  2  1  0 |
+|-------+-----------------|
+|  0  0 |     index       |
+`-------------------------`
+2-bit tag b00
+6-bit index into the color index array: 0..63
+
+
+.- QOI_OP_DIFF -----------. 
+|         Byte[0]         |
+|  7  6  5  4  3  2  1  0 |
+|-------+-----+-----+-----|
+|  0  1 |  dr |  dg |  db |
+`-------------------------`
+2-bit tag b01
+2-bit   red channel difference from the previous pixel between -2..1
+2-bit green channel difference from the previous pixel between -2..1
+2-bit  blue channel difference from the previous pixel between -2..1
+
+The difference to the current channel values are using a wraparound operation, 
+so "1 - 2" will result in 255, while "255 + 1" will result in 0.
+
+Values are stored as unsigned integers with a bias of 2. E.g. -2 is stored as 
+0 (b00). 1 is stored as 3 (b11).
+
+
+.- QOI_OP_LUMA -------------------------------------. 
+|         Byte[0]         |         Byte[1]         |
+|  7  6  5  4  3  2  1  0 |  7  6  5  4  3  2  1  0 |
+|-------+-----------------+-------------+-----------|
+|  1  0 |  green diff     |   dr - dg   |  db - dg  |
+`---------------------------------------------------`
+2-bit tag b10
+6-bit green channel difference from the previous pixel -32..31
+4-bit   red channel difference minus green channel difference -8..7
+4-bit  blue channel difference minus green channel difference -8..7
+
+The green channel is used to indicate the general direction of change and is 
+encoded in 6 bits. The red and green channels (dr and db) base their diffs off
+of the green channel difference and are encoded in 4 bits. I.e.:
+  dr_dg = (last_px.r - cur_px.r) - (last_px.g - cur_px.g)
+  db_dg = (last_px.b - cur_px.b) - (last_px.g - cur_px.g)
+
+The difference to the current channel values are using a wraparound operation, 
+so "10 - 13" will result in 253, while "250 + 7" will result in 1.
+
+Values are stored as unsigned integers with a bias of 32 for the green channel 
+and a bias of 8 for the red and blue channel.
+
+
+.- QOI_OP_RUN ------------.
+|         Byte[0]         |
+|  7  6  5  4  3  2  1  0 |
+|-------+-----------------|
+|  1  1 |       run       |
+`-------------------------`
+2-bit tag b11
+6-bit run-length repeating the previous pixel: 1..62
+
+The run-length is stored with a bias of 1. Note that the run-lengths 63 and 64 
+(b111110 and b111111) are illegal as they are occupied by the QOI_OP_RGB and 
+QOI_OP_RGBA tags.
+
+
+.- QOI_OP_RGB ------------------------------------------.
+|         Byte[0]         | Byte[1] | Byte[2] | Byte[3] |
+|  7  6  5  4  3  2  1  0 | 7 .. 0  | 7 .. 0  | 7 .. 0  |
+|-------------------------+---------+---------+---------|
+|  1  1  1  1  1  1  1  0 |   red   |  green  |  blue   |
+`-------------------------------------------------------`
+8-bit tag b11111110
+8-bit   red channel value
+8-bit green channel value
+8-bit  blue channel value
+
+
+.- QOI_OP_RGBA ---------------------------------------------------.
+|         Byte[0]         | Byte[1] | Byte[2] | Byte[3] | Byte[4] |
+|  7  6  5  4  3  2  1  0 | 7 .. 0  | 7 .. 0  | 7 .. 0  | 7 .. 0  |
+|-------------------------+---------+---------+---------+---------|
+|  1  1  1  1  1  1  1  1 |   red   |  green  |  blue   |  alpha  |
+`-----------------------------------------------------------------`
+8-bit tag b11111111
+8-bit   red channel value
+8-bit green channel value
+8-bit  blue channel value
+8-bit alpha channel value
+
+
+The byte stream is padded at the end with 8 zero bytes. Since the longest legal 
+chunk is 5 bytes (QOI_OP_RGBA), with this padding it is possible to check for an
+overrun only once per decode loop iteration. These 0x00 bytes also mark the end
+of the data stream, as an encoder should never produce 8 consecutive zero bytes
+within the stream.
+
+*/
+
+
+/* -----------------------------------------------------------------------------
+Header - Public functions */
+
+#ifndef QOI_H
+#define QOI_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* A pointer to a qoi_desc struct has to be supplied to all of qoi's functions. 
+It describes either the input format (for qoi_write and qoi_encode), or is 
+filled with the description read from the file header (for qoi_read and
+qoi_decode).
+
+The colorspace in this qoi_desc is an enum where 
+	0 = sRGB, i.e. gamma scaled RGB channels and a linear alpha channel
+	1 = all channels are linear
+You may use the constants QOI_SRGB or QOI_LINEAR. The colorspace is purely 
+informative. It will be saved to the file header, but does not affect
+en-/decoding in any way. */
+
+#define QOI_SRGB   0
+#define QOI_LINEAR 1
+
+typedef struct {
+	unsigned int width;
+	unsigned int height;
+	unsigned char channels;
+	unsigned char colorspace;
+} qoi_desc;
+
+#ifndef QOI_NO_STDIO
+
+/* Encode raw RGB or RGBA pixels into a QOI image and write it to the file 
+system. The qoi_desc struct must be filled with the image width, height, 
+number of channels (3 = RGB, 4 = RGBA) and the colorspace. 
+
+The function returns 0 on failure (invalid parameters, or fopen or malloc 
+failed) or the number of bytes written on success. */
+
+int qoi_write(const char *filename, const void *data, const qoi_desc *desc);
+
+
+/* Read and decode a QOI image from the file system. If channels is 0, the
+number of channels from the file header is used. If channels is 3 or 4 the
+output format will be forced into this number of channels.
+
+The function either returns NULL on failure (invalid data, or malloc or fopen
+failed) or a pointer to the decoded pixels. On success, the qoi_desc struct 
+will be filled with the description from the file header.
+
+The returned pixel data should be free()d after use. */
+
+void *qoi_read(const char *filename, qoi_desc *desc, int channels);
+
+#endif /* QOI_NO_STDIO */
+
+
+/* Encode raw RGB or RGBA pixels into a QOI image in memory.
+
+The function either returns NULL on failure (invalid parameters or malloc 
+failed) or a pointer to the encoded data on success. On success the out_len 
+is set to the size in bytes of the encoded data.
+
+The returned qoi data should be free()d after use. */
+
+void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len);
+
+
+/* Decode a QOI image from memory.
+
+The function either returns NULL on failure (invalid parameters or malloc 
+failed) or a pointer to the decoded pixels. On success, the qoi_desc struct 
+is filled with the description from the file header.
+
+The returned pixel data should be free()d after use. */
+
+void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels);
+
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* QOI_H */
+
+
+/* -----------------------------------------------------------------------------
+Implementation */
+
+#ifdef QOI_IMPLEMENTATION
+#include <stdlib.h>
+#include <string.h>
+
+#ifndef QOI_MALLOC
+	#define QOI_MALLOC(sz) malloc(sz)
+	#define QOI_FREE(p)    free(p)
+#endif
+#ifndef QOI_ZEROARR
+	#define QOI_ZEROARR(a) memset((a),0,sizeof(a))
+#endif
+
+#define QOI_OP_INDEX  0x00 /* 00xxxxxx */
+#define QOI_OP_DIFF   0x40 /* 01xxxxxx */
+#define QOI_OP_LUMA   0x80 /* 10xxxxxx */
+#define QOI_OP_RUN    0xc0 /* 11xxxxxx */
+#define QOI_OP_RGB    0xfe /* 11111110 */
+#define QOI_OP_RGBA   0xff /* 11111111 */
+
+#define QOI_MASK_2    0xc0 /* 11000000 */
+
+#define QOI_COLOR_HASH(C) (C.rgba.r*3 + C.rgba.g*5 + C.rgba.b*7 + C.rgba.a*11)
+#define QOI_MAGIC \
+	(((unsigned int)'q') << 24 | ((unsigned int)'o') << 16 | \
+	 ((unsigned int)'i') <<  8 | ((unsigned int)'f'))
+#define QOI_HEADER_SIZE 14
+#define QOI_PADDING 8
+
+typedef union {
+	struct { unsigned char r, g, b, a; } rgba;
+	unsigned int v;
+} qoi_rgba_t;
+
+void qoi_write_32(unsigned char *bytes, int *p, unsigned int v) {
+	bytes[(*p)++] = (0xff000000 & v) >> 24;
+	bytes[(*p)++] = (0x00ff0000 & v) >> 16;
+	bytes[(*p)++] = (0x0000ff00 & v) >> 8;
+	bytes[(*p)++] = (0x000000ff & v);
+}
+
+unsigned int qoi_read_32(const unsigned char *bytes, int *p) {
+	unsigned int a = bytes[(*p)++];
+	unsigned int b = bytes[(*p)++];
+	unsigned int c = bytes[(*p)++];
+	unsigned int d = bytes[(*p)++];
+	return a << 24 | b << 16 | c << 8 | d;
+}
+
+void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len) {
+	int i, max_size, p, run;
+	int px_len, px_end, px_pos, channels;
+	unsigned char *bytes;
+	const unsigned char *pixels;
+	qoi_rgba_t index[64];
+	qoi_rgba_t px, px_prev;
+
+	if (
+		data == NULL || out_len == NULL || desc == NULL ||
+		desc->width == 0 || desc->height == 0 ||
+		desc->channels < 3 || desc->channels > 4 ||
+		desc->colorspace > 2
+	) {
+		return NULL;
+	}
+
+	max_size = 
+		desc->width * desc->height * (desc->channels + 1) + 
+		QOI_HEADER_SIZE + QOI_PADDING;
+
+	p = 0;
+	bytes = (unsigned char *) QOI_MALLOC(max_size);
+	if (!bytes) {
+		return NULL;
+	}
+
+	qoi_write_32(bytes, &p, QOI_MAGIC);
+	qoi_write_32(bytes, &p, desc->width);
+	qoi_write_32(bytes, &p, desc->height);
+	bytes[p++] = desc->channels;
+	bytes[p++] = desc->colorspace;
+
+
+	pixels = (const unsigned char *)data;
+
+	QOI_ZEROARR(index);
+
+	run = 0;
+	px_prev.rgba.r = 0;
+	px_prev.rgba.g = 0;
+	px_prev.rgba.b = 0;
+	px_prev.rgba.a = 255;
+	px = px_prev;
+	
+	px_len = desc->width * desc->height * desc->channels;
+	px_end = px_len - desc->channels;
+	channels = desc->channels;
+
+	for (px_pos = 0; px_pos < px_len; px_pos += channels) {
+		if (channels == 4) {
+			px = *(qoi_rgba_t *)(pixels + px_pos);
+		}
+		else {
+			px.rgba.r = pixels[px_pos + 0];
+			px.rgba.g = pixels[px_pos + 1];
+			px.rgba.b = pixels[px_pos + 2];
+		}
+
+		if (px.v == px_prev.v) {
+			run++;
+			if (run == 62 || px_pos == px_end) {
+				bytes[p++] = QOI_OP_RUN | (run - 1);
+				run = 0;
+			}
+		}
+		else {
+			int index_pos;
+
+			if (run > 0) {
+				bytes[p++] = QOI_OP_RUN | (run - 1);
+				run = 0;
+			}
+
+			index_pos = QOI_COLOR_HASH(px) % 64;
+
+			if (index[index_pos].v == px.v) {
+				bytes[p++] = QOI_OP_INDEX | index_pos;
+			}
+			else {
+				index[index_pos] = px;
+
+				if (px.rgba.a == px_prev.rgba.a) {
+					signed char vr = px.rgba.r - px_prev.rgba.r;
+					signed char vg = px.rgba.g - px_prev.rgba.g;
+					signed char vb = px.rgba.b - px_prev.rgba.b;
+
+					signed char vg_r = vr - vg;
+					signed char vg_b = vb - vg;
+
+					if (
+						vr > -3 && vr < 2 &&
+						vg > -3 && vg < 2 && 
+						vb > -3 && vb < 2
+					) {
+						bytes[p++] = QOI_OP_DIFF | (vr + 2) << 4 | (vg + 2) << 2 | (vb + 2);
+					}
+					else if (
+						vg_r >  -9 && vg_r <  8 && 
+						vg   > -33 && vg   < 32 && 
+						vg_b >  -9 && vg_b <  8
+					) {
+						bytes[p++] = QOI_OP_LUMA     | (vg   + 32);
+						bytes[p++] = (vg_r + 8) << 4 | (vg_b +  8);
+					}
+					else {
+						bytes[p++] = QOI_OP_RGB;
+						bytes[p++] = px.rgba.r;
+						bytes[p++] = px.rgba.g;
+						bytes[p++] = px.rgba.b;
+					}
+				}
+				else {
+					bytes[p++] = QOI_OP_RGBA;
+					bytes[p++] = px.rgba.r;
+					bytes[p++] = px.rgba.g;
+					bytes[p++] = px.rgba.b;
+					bytes[p++] = px.rgba.a;
+				}
+			}
+		}
+		px_prev = px;
+	}
+
+	for (i = 0; i < QOI_PADDING; i++) {
+		bytes[p++] = 0;
+	}
+
+	*out_len = p;
+	return bytes;
+}
+
+void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels) {
+	const unsigned char *bytes;
+	unsigned int header_magic;
+	unsigned char *pixels;
+	qoi_rgba_t index[64];
+	qoi_rgba_t px;
+	int px_len,  chunks_len, px_pos;
+	int p = 0, run = 0;
+
+	if (
+		data == NULL || desc == NULL ||
+		(channels != 0 && channels != 3 && channels != 4) ||
+		size < QOI_HEADER_SIZE + QOI_PADDING
+	) {
+		return NULL;
+	}
+
+	bytes = (const unsigned char *)data;
+
+	header_magic = qoi_read_32(bytes, &p);
+	desc->width = qoi_read_32(bytes, &p);
+	desc->height = qoi_read_32(bytes, &p);
+	desc->channels = bytes[p++];
+	desc->colorspace = bytes[p++];
+
+	if (
+		desc->width == 0 || desc->height == 0 || 
+		desc->channels < 3 || desc->channels > 4 ||
+		desc->colorspace > 2 ||
+		header_magic != QOI_MAGIC
+	) {
+		return NULL;
+	}
+
+	if (channels == 0) {
+		channels = desc->channels;
+	}
+
+	px_len = desc->width * desc->height * channels;
+	pixels = (unsigned char *) QOI_MALLOC(px_len);
+	if (!pixels) {
+		return NULL;
+	}
+
+	QOI_ZEROARR(index);
+	px.rgba.r = 0;
+	px.rgba.g = 0;
+	px.rgba.b = 0;
+	px.rgba.a = 255;
+
+	chunks_len = size - QOI_PADDING;
+	for (px_pos = 0; px_pos < px_len; px_pos += channels) {
+		if (run > 0) {
+			run--;
+		}
+		else if (p < chunks_len) {
+			int b1 = bytes[p++];
+
+			if (b1 == QOI_OP_RGB) {
+				px.rgba.r = bytes[p++];
+				px.rgba.g = bytes[p++];
+				px.rgba.b = bytes[p++];
+			}
+			else if (b1 == QOI_OP_RGBA) {
+				px.rgba.r = bytes[p++];
+				px.rgba.g = bytes[p++];
+				px.rgba.b = bytes[p++];
+				px.rgba.a = bytes[p++];
+			}
+			else if ((b1 & QOI_MASK_2) == QOI_OP_INDEX) {
+				px = index[b1];
+			}
+			else if ((b1 & QOI_MASK_2) == QOI_OP_DIFF) {
+				px.rgba.r += ((b1 >> 4) & 0x03) - 2;
+				px.rgba.g += ((b1 >> 2) & 0x03) - 2;
+				px.rgba.b += ( b1       & 0x03) - 2;
+			}
+			else if ((b1 & QOI_MASK_2) == QOI_OP_LUMA) {
+				int b2 = bytes[p++];
+				int vg = (b1 & 0x3f) - 32;
+				px.rgba.r += vg - 8 + ((b2 >> 4) & 0x0f);
+				px.rgba.g += vg;
+				px.rgba.b += vg - 8 +  (b2       & 0x0f);
+			}
+			else if ((b1 & QOI_MASK_2) == QOI_OP_RUN) {
+				run = (b1 & 0x3f);
+			}
+
+			index[QOI_COLOR_HASH(px) % 64] = px;
+		}
+
+		if (channels == 4) { 
+			*(qoi_rgba_t*)(pixels + px_pos) = px;
+		}
+		else {
+			pixels[px_pos + 0] = px.rgba.r;
+			pixels[px_pos + 1] = px.rgba.g;
+			pixels[px_pos + 2] = px.rgba.b;
+		}
+	}
+
+	return pixels;
+}
+
+#ifndef QOI_NO_STDIO
+#include <stdio.h>
+
+int qoi_write(const char *filename, const void *data, const qoi_desc *desc) {
+	FILE *f = fopen(filename, "wb");
+	int size;
+	void *encoded;
+
+	if (!f) {
+		return 0;
+	}
+
+	encoded = qoi_encode(data, desc, &size);
+	if (!encoded) {
+		fclose(f);
+		return 0;
+	}	
+	
+	fwrite(encoded, 1, size, f);
+	fclose(f);
+	
+	QOI_FREE(encoded);
+	return size;
+}
+
+void *qoi_read(const char *filename, qoi_desc *desc, int channels) {
+	FILE *f = fopen(filename, "rb");
+	int size, bytes_read;
+	void *pixels, *data;
+
+	if (!f) {
+		return NULL;
+	}
+
+	fseek(f, 0, SEEK_END);
+	size = ftell(f);
+	fseek(f, 0, SEEK_SET);
+
+	data = QOI_MALLOC(size);
+	if (!data) {
+		fclose(f);
+		return NULL;
+	}
+
+	bytes_read = fread(data, 1, size, f);
+	fclose(f);
+
+	pixels = qoi_decode(data, bytes_read, desc, channels);
+	QOI_FREE(data);
+	return pixels;
+}
+
+#endif /* QOI_NO_STDIO */
+#endif /* QOI_IMPLEMENTATION */