Add get_row_pitch helper function

Added premake solution to more easily pick up where we left off and modify properties
Fix some warnings and non-standard usages

.gitignore

@@ -0,0 +1,15 @@
+# User files
+*.suo
+*.user
+*.sln.docstates
+
+# Build folders
+
+workspace/
+
+# Visual Studio Intermediate files
+*.opendb
+*.db
+
+# Temporary
+*.tmp

Visual Studio 2010.bat

@@ -0,0 +1,3 @@
+@echo off
+start /B /W premake/win/premake5 --file=ddspp.lua vs2010
+pause

ddspp.h

@@ -362,8 +362,8 @@ namespace ddspp
 		unsigned int rowPitch; // Row pitch for mip 0
 		unsigned int depthPitch; // Size of mip 0
 		unsigned int bitsPerPixelOrBlock; // If compressed bits per block, else bits per pixel
-		unsigned int blockWidth;
-		unsigned int blockHeight;
+		unsigned int blockWidth; // Width of block in pixels (1 if uncompressed)
+		unsigned int blockHeight;// Height of block in pixels (1 if uncompressed)
 		bool compressed;
 		bool srgb;
 		unsigned int headerSize; // Actual size of header, use this to get to image data
@@ -599,13 +599,27 @@ namespace ddspp
 		return;
 	}
 
+	inline ddspp_constexpr unsigned int get_row_pitch(unsigned int width, unsigned int bitsPerPixelOrBlock, unsigned int blockWidth, unsigned int mip)
+	{
+		// Shift width by mipmap index, round to next block size and round to next byte (for the rare less than 1 byte per pixel formats)
+		// E.g. width = 119, mip = 3, BC1 compression
+		// ((((119 >> 2) + 4 - 1) / 4) * 64) / 8 = 64 bytes
+		return ((((width >> mip) + blockWidth - 1) / blockWidth) * bitsPerPixelOrBlock + 7) / 8;
+	}
+
+	// Returns number of bytes for each row of a given mip. Valid range is [0, desc.numMips)
+	inline ddspp_constexpr unsigned int get_row_pitch(const Descriptor& desc, unsigned int mip)
+	{
+		return get_row_pitch(desc.width, desc.bitsPerPixelOrBlock, desc.blockWidth, mip);
+	}
+
 	inline Result decode_header(unsigned char* sourceData, Descriptor& desc)
 	{
 		unsigned int magic = *reinterpret_cast<unsigned int*>(sourceData); // First 4 bytes are the magic DDS number
 
 		if (magic != DDS_MAGIC)
 		{
-			return Result::Error;
+			return ddspp::Error;
 		}
 
 		const Header header = *reinterpret_cast<const Header*>(sourceData + sizeof(DDS_MAGIC));
@@ -859,7 +873,7 @@ namespace ddspp
 		{
 			if((header.caps2 & DDS_HEADER_CAPS2_CUBEMAP_ALLFACES) != DDS_HEADER_CAPS2_CUBEMAP_ALLFACES)
 			{
-				return Result::Error;
+				return ddspp::Error;
 			}
 
 			desc.type = Cubemap;
@@ -909,11 +923,11 @@ namespace ddspp
 		desc.bitsPerPixelOrBlock = get_bits_per_pixel_or_block(desc.format);
 		get_block_size(desc.format, desc.blockWidth, desc.blockHeight);
 
-		desc.rowPitch = desc.width * desc.bitsPerPixelOrBlock / (8 * desc.blockWidth);
+		desc.rowPitch = get_row_pitch(desc.width, desc.bitsPerPixelOrBlock, desc.blockWidth, 0);
 		desc.depthPitch = desc.rowPitch * desc.height / desc.blockHeight;
 		desc.headerSize = sizeof(DDS_MAGIC) + sizeof(Header) + (dxt10Extension ? sizeof(HeaderDXT10) : 0);
 
-		return Result::Success;
+		return ddspp::Success;
 	}
 
 	inline void encode_header(const DXGIFormat format, const unsigned int width, const unsigned int height, const unsigned int depth,

ddspp.lua

@@ -0,0 +1,95 @@
+Workspace = "workspace/".._ACTION
+
+-- Compilers
+
+-- x86/x64
+PlatformMSVC64			= "MSVC 64"
+PlatformOSX64			= "OSX 64"
+PlatformLinux64_GCC		= "Linux64_GCC"
+PlatformLinux64_Clang	= "Linux64_Clang"
+
+isMacBuild = _ACTION == "xcode4"
+isLinuxBuild = _ACTION == "gmake2"
+isWindowsBuild = not isMacBuild and not isLinuxBuild
+supportsARMBuild = _ACTION == "vs2017" or _ACTION == "vs2019" or _ACTION == "vs2022"
+
+workspace("dds++")
+	configurations { "Debug", "Release" }
+	location (Workspace)
+
+	flags
+	{
+		"multiprocessorcompile", -- /MP
+	}
+
+	includedirs
+	{
+		includeDir,
+	}
+
+	cppdialect("c++11")
+
+	if(isMacBuild) then
+
+		platforms { PlatformOSX64 }
+		toolset("clang")
+		architecture("x64")
+		buildoptions { "-std=c++11 -Wno-unused-variable" }
+		linkoptions { "-stdlib=libc++" }
+
+	elseif(isLinuxBuild) then
+
+		platforms { PlatformLinux64_GCC, PlatformLinux64_Clang }
+		architecture("x64")
+		buildoptions { "-std=c++11 -Wno-unused-variable" }
+
+		filter { "platforms:"..PlatformLinux64_GCC }
+			toolset("gcc")
+
+		filter { "platforms:"..PlatformLinux64_Clang }
+			toolset("clang")
+
+	else
+
+		platforms
+		{
+			PlatformMSVC64
+		}
+
+		local llvmToolset;
+
+		if (_ACTION == "vs2015") then
+			llvmToolset = "msc-llvm-vs2014";
+		elseif(_ACTION == "vs2017") then
+			llvmToolset = "msc-llvm";
+		else
+			llvmToolset = "msc-clangcl";
+		end
+
+		startproject(UnitTestProject)
+
+		filter { "platforms:"..PlatformMSVC64 }
+			toolset("msc")
+			architecture("x64")
+
+		filter{}
+	end
+
+	filter { "configurations:Debug" }
+		defines { "DEBUG" }
+		symbols ("full")
+		optimize("debug")
+
+	filter { "configurations:Release" }
+		defines { "NDEBUG" }
+		inlining("auto")
+		optimize("speed")
+
+project ('dds++')
+	kind("consoleapp")
+
+	files
+	{
+		"*.cpp",
+		"*.h",
+	}

main.cpp

@@ -19,11 +19,17 @@ int main()
 	fread(data, sizeof(*data), ddsSize, fh);
 
 	ddspp::Descriptor desc;
-	unsigned char* ddsData = ddspp::decode_header(data, desc);
+	ddspp::Result ddsResult = ddspp::decode_header(data, desc);
 
-	ddspp::Header h;
+	ddspp::Header header;
 	ddspp::HeaderDXT10 h10;
-	ddspp::encode_header(desc.format, desc.width, desc.height, desc.depth, desc.type, desc.numMips, desc.arraySize, h, h10);
+	ddspp::encode_header(desc.format, desc.width, desc.height, desc.depth, desc.type, desc.numMips, desc.arraySize, header, h10);
+
+	unsigned int rowPitch512 = ddspp::get_row_pitch(512, 64, 4, 0);
+
+	unsigned int rowPitch = ddspp::get_row_pitch(29, 8, 1, 0);
+
+	unsigned int rowPitchDesc = ddspp::get_row_pitch(desc, 0);
 
 	unsigned int offset = ddspp::get_offset(desc, 4, 0);