1 files changed, 413 insertions, 0 deletions
diff --git a/Src/external_dependencies/openmpt-trunk/soundlib/ITCompression.cpp b/Src/external_dependencies/openmpt-trunk/soundlib/ITCompression.cpp
new file mode 100644
index 00000000..1d45f0ad
--- /dev/null
+++ b/Src/external_dependencies/openmpt-trunk/soundlib/ITCompression.cpp
@@ -0,0 +1,413 @@
+/*
+ * ITCompression.cpp
+ * -----------------
+ * Purpose: Code for IT sample compression and decompression.
+ * Notes  : The original Python compression code was written by GreaseMonkey and has been released into the public domain.
+ * Authors: OpenMPT Devs
+ *          Ben "GreaseMonkey" Russell
+ * The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
+ */
+
+
+#include "stdafx.h"
+#include <ostream>
+#include "ITCompression.h"
+#include "mpt/io/base.hpp"
+#include "mpt/io/io.hpp"
+#include "mpt/io/io_stdstream.hpp"
+#include "../common/misc_util.h"
+#include "ModSample.h"
+#include "SampleCopy.h"
+
+
+OPENMPT_NAMESPACE_BEGIN
+
+
+// Algorithm parameters for 16-Bit samples
+struct IT16BitParams
+{
+	using sample_t = int16;
+	static constexpr int16 lowerTab[] = {0, -1, -3, -7, -15, -31, -56, -120, -248, -504, -1016, -2040, -4088, -8184, -16376, -32760, -32768};
+	static constexpr int16 upperTab[] = {0, 1, 3, 7, 15, 31, 55, 119, 247, 503, 1015, 2039, 4087, 8183, 16375, 32759, 32767};
+	static constexpr int8 fetchA = 4;
+	static constexpr int8 lowerB = -8;
+	static constexpr int8 upperB = 7;
+	static constexpr int8 defWidth = 17;
+	static constexpr int mask = 0xFFFF;
+};
+
+// Algorithm parameters for 8-Bit samples
+struct IT8BitParams
+{
+	using sample_t = int8;
+	static constexpr int8 lowerTab[] = {0, -1, -3, -7, -15, -31, -60, -124, -128};
+	static constexpr int8 upperTab[] = {0, 1, 3, 7, 15, 31, 59, 123, 127};
+	static constexpr int8 fetchA = 3;
+	static constexpr int8 lowerB = -4;
+	static constexpr int8 upperB = 3;
+	static constexpr int8 defWidth = 9;
+	static constexpr int mask = 0xFF;
+};
+
+static constexpr int8 ITWidthChangeSize[] = { 4, 5, 6, 7, 8, 9, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 };
+
+//////////////////////////////////////////////////////////////////////////////
+// IT 2.14 compression
+
+
+ITCompression::ITCompression(const ModSample &sample, bool it215, std::ostream *f, SmpLength maxLength)
+    : file(f)
+    , mptSample(sample)
+    , is215(it215)
+{
+	if(mptSample.GetElementarySampleSize() > 1)
+		Compress<IT16BitParams>(mptSample.sample16(), maxLength);
+	else
+		Compress<IT8BitParams>(mptSample.sample8(), maxLength);
+}
+
+
+template<typename Properties>
+void ITCompression::Compress(const typename Properties::sample_t *mptSampleData, SmpLength maxLength)
+{
+	packedData.resize(bufferSize);
+	std::vector<typename Properties::sample_t> sampleData;
+	sampleData.resize(blockSize / sizeof(typename Properties::sample_t));
+	if(maxLength == 0 || maxLength > mptSample.nLength)
+		maxLength = mptSample.nLength;
+	for(uint8 chn = 0; chn < mptSample.GetNumChannels(); chn++)
+	{
+		SmpLength offset = 0;
+		SmpLength remain = maxLength;
+		while(remain > 0)
+		{
+			// Initialise output buffer and bit writer positions
+			packedLength = 2;
+			bitPos = 0;
+			remBits = 8;
+			byteVal = 0;
+
+			CompressBlock<Properties>(mptSampleData + chn, offset, remain, sampleData.data());
+
+			if(file) mpt::IO::WriteRaw(*file, packedData.data(), packedLength);
+			packedTotalLength += packedLength;
+
+			offset += baseLength;
+			remain -= baseLength;
+		}
+	}
+	packedData.resize(0);
+	packedData.shrink_to_fit();
+}
+
+
+template<typename T>
+void ITCompression::CopySample(T *target, const T *source, SmpLength offset, SmpLength length, SmpLength skip)
+{
+	T *out = target;
+	const T *in = source + offset * skip;
+	for(SmpLength i = 0, j = 0; j < length; i += skip, j++)
+	{
+		out[j] = in[i];
+	}
+}
+
+
+// Convert sample to delta values.
+template<typename T>
+void ITCompression::Deltafy(T *sampleData)
+{
+	T *p = sampleData;
+	int oldVal = 0;
+	for(SmpLength i = 0; i < baseLength; i++)
+	{
+		int newVal = p[i];
+		p[i] = static_cast<T>(newVal - oldVal);
+		oldVal = newVal;
+	}
+}
+
+
+template<typename Properties>
+void ITCompression::CompressBlock(const typename Properties::sample_t *data, SmpLength offset, SmpLength actualLength, typename Properties::sample_t *sampleData)
+{
+	baseLength = std::min(actualLength, SmpLength(blockSize / sizeof(typename Properties::sample_t)));
+
+	CopySample<typename Properties::sample_t>(sampleData, data, offset, baseLength, mptSample.GetNumChannels());
+
+	Deltafy(sampleData);
+	if(is215)
+	{
+		Deltafy(sampleData);
+	}
+
+	// Initialise bit width table with initial values
+	bwt.assign(baseLength, Properties::defWidth);
+
+	// Recurse!
+	SquishRecurse<Properties>(Properties::defWidth, Properties::defWidth, Properties::defWidth, Properties::defWidth - 2, 0, baseLength, sampleData);
+	
+	// Write those bits!
+	const typename Properties::sample_t *p = sampleData;
+	int8 width = Properties::defWidth;
+	for(size_t i = 0; i < baseLength; i++)
+	{
+		if(bwt[i] != width)
+		{
+			if(width <= 6)
+			{
+				// Mode A: 1 to 6 bits
+				MPT_ASSERT(width);
+				WriteBits(width, (1 << (width - 1)));
+				WriteBits(Properties::fetchA, ConvertWidth(width, bwt[i]));
+			} else if(width < Properties::defWidth)
+			{
+				// Mode B: 7 to 8 / 16 bits
+				int xv = (1 << (width - 1)) + Properties::lowerB + ConvertWidth(width, bwt[i]);
+				WriteBits(width, xv);
+			} else
+			{
+				// Mode C: 9 / 17 bits
+				MPT_ASSERT((bwt[i] - 1) >= 0);
+				WriteBits(width, (1 << (width - 1)) + bwt[i] - 1);
+			}
+
+			width = bwt[i];
+		}
+		WriteBits(width, static_cast<int>(p[i]) & Properties::mask);
+	}
+
+	// Write last byte and update block length
+	WriteByte(byteVal);
+	packedData[0] = static_cast<uint8>((packedLength - 2) & 0xFF);
+	packedData[1] = static_cast<uint8>((packedLength - 2) >> 8);
+}
+
+
+int8 ITCompression::GetWidthChangeSize(int8 w, bool is16)
+{
+	MPT_ASSERT(w > 0 && static_cast<unsigned int>(w) <= std::size(ITWidthChangeSize));
+	int8 wcs = ITWidthChangeSize[w - 1];
+	if(w <= 6 && is16)
+		wcs++;
+	return wcs;
+}
+
+
+template<typename Properties>
+void ITCompression::SquishRecurse(int8 sWidth, int8 lWidth, int8 rWidth, int8 width, SmpLength offset, SmpLength length, const typename Properties::sample_t *sampleData)
+{
+	if(width + 1 < 1)
+	{
+		for(SmpLength i = offset; i < offset + length; i++)
+			bwt[i] = sWidth;
+		return;
+	}
+
+	MPT_ASSERT(width >= 0 && static_cast<unsigned int>(width) < std::size(Properties::lowerTab));
+
+	SmpLength i = offset;
+	SmpLength end = offset + length;
+	const typename Properties::sample_t *p = sampleData;
+
+	while(i < end)
+	{
+		if(p[i] >= Properties::lowerTab[width] && p[i] <= Properties::upperTab[width])
+		{
+			SmpLength start = i;
+			// Check for how long we can keep this bit width
+			while(i < end && p[i] >= Properties::lowerTab[width] && p[i] <= Properties::upperTab[width])
+			{
+				i++;
+			}
+
+			const SmpLength blockLength = i - start;
+			const int8 xlwidth = start == offset ? lWidth : sWidth;
+			const int8 xrwidth = i == end ? rWidth : sWidth;
+
+			const bool is16 = sizeof(typename Properties::sample_t) > 1;
+			const int8 wcsl = GetWidthChangeSize(xlwidth, is16);
+			const int8 wcss = GetWidthChangeSize(sWidth, is16);
+			const int8 wcsw = GetWidthChangeSize(width + 1, is16);
+
+			bool comparison;
+			if(i == baseLength)
+			{
+				SmpLength keepDown = wcsl + (width + 1) * blockLength;
+				SmpLength levelLeft = wcsl + sWidth * blockLength;
+
+				if(xlwidth == sWidth)
+					levelLeft -= wcsl;
+
+				comparison = (keepDown <= levelLeft);
+			} else
+			{
+				SmpLength keepDown = wcsl + (width + 1) * blockLength + wcsw;
+				SmpLength levelLeft = wcsl + sWidth * blockLength + wcss;
+
+				if(xlwidth == sWidth)
+					levelLeft -= wcsl;
+				if(xrwidth == sWidth)
+					levelLeft -= wcss;
+
+				comparison = (keepDown <= levelLeft);
+			}
+			SquishRecurse<Properties>(comparison ? (width + 1) : sWidth, xlwidth, xrwidth, width - 1, start, blockLength, sampleData);
+		} else
+		{
+			bwt[i] = sWidth;
+			i++;
+		}
+	}
+}
+
+
+int8 ITCompression::ConvertWidth(int8 curWidth, int8 newWidth)
+{
+	curWidth--;
+	newWidth--;
+	MPT_ASSERT(newWidth != curWidth);
+	if(newWidth > curWidth)
+		newWidth--;
+	return newWidth;
+}
+
+
+void ITCompression::WriteBits(int8 width, int v)
+{
+	while(width > remBits)
+	{
+		byteVal |= (v << bitPos);
+		width -= remBits;
+		v >>= remBits;
+		bitPos = 0;
+		remBits = 8;
+		WriteByte(byteVal);
+		byteVal = 0;
+	}
+
+	if(width > 0)
+	{
+		byteVal |= (v & ((1 << width) - 1)) << bitPos;
+		remBits -= width;
+		bitPos += width;
+	}
+}
+
+
+void ITCompression::WriteByte(uint8 v)
+{
+	if(packedLength < bufferSize)
+	{
+		packedData[packedLength++] = v;
+	} else
+	{
+		// How could this happen, anyway?
+		MPT_ASSERT_NOTREACHED();
+	}
+}
+
+
+//////////////////////////////////////////////////////////////////////////////
+// IT 2.14 decompression
+
+
+ITDecompression::ITDecompression(FileReader &file, ModSample &sample, bool it215)
+    : mptSample(sample)
+    , is215(it215)
+{
+	for(uint8 chn = 0; chn < mptSample.GetNumChannels(); chn++)
+	{
+		writtenSamples = writePos = 0;
+		while(writtenSamples < sample.nLength && file.CanRead(sizeof(uint16)))
+		{
+			uint16 compressedSize = file.ReadUint16LE();
+			if(!compressedSize)
+				continue;	// Malformed sample?
+			bitFile = file.ReadChunk(compressedSize);
+
+			// Initialise bit reader
+			mem1 = mem2 = 0;
+
+			try
+			{
+				if(mptSample.GetElementarySampleSize() > 1)
+					Uncompress<IT16BitParams>(mptSample.sample16() + chn);
+				else
+					Uncompress<IT8BitParams>(mptSample.sample8() + chn);
+			} catch(const BitReader::eof &)
+			{
+				// Data is not sufficient to decode the block
+				//AddToLog(LogWarning, "Truncated IT sample block");
+			}
+		}
+	}
+}
+
+
+template<typename Properties>
+void ITDecompression::Uncompress(typename Properties::sample_t *target)
+{
+	curLength = std::min(mptSample.nLength - writtenSamples, SmpLength(ITCompression::blockSize / sizeof(typename Properties::sample_t)));
+
+	int width = Properties::defWidth;
+	while(curLength > 0)
+	{
+		if(width > Properties::defWidth)
+		{
+			// Error!
+			return;
+		}
+
+		int v = bitFile.ReadBits(width);
+		const int topBit = (1 << (width - 1));
+		if(width <= 6)
+		{
+			// Mode A: 1 to 6 bits
+			if(v == topBit)
+				ChangeWidth(width, bitFile.ReadBits(Properties::fetchA));
+			else
+				Write<Properties>(v, topBit, target);
+		} else if(width < Properties::defWidth)
+		{
+			// Mode B: 7 to 8 / 16 bits
+			if(v >= topBit + Properties::lowerB && v <= topBit + Properties::upperB)
+				ChangeWidth(width, v - (topBit + Properties::lowerB));
+			else
+				Write<Properties>(v, topBit, target);
+		} else
+		{
+			// Mode C: 9 / 17 bits
+			if(v & topBit)
+				width = (v & ~topBit) + 1;
+			else
+				Write<Properties>((v & ~topBit), 0, target);
+		}
+	}
+}
+
+
+void ITDecompression::ChangeWidth(int &curWidth, int width)
+{
+	width++;
+	if(width >= curWidth)
+		width++;
+	curWidth = width;
+}
+
+
+template<typename Properties>
+void ITDecompression::Write(int v, int topBit, typename Properties::sample_t *target)
+{
+	if(v & topBit)
+		v -= (topBit << 1);
+	mem1 += v;
+	mem2 += mem1;
+	target[writePos] = static_cast<typename Properties::sample_t>(static_cast<int>(is215 ? mem2 : mem1));
+	writtenSamples++;
+	writePos += mptSample.GetNumChannels();
+	curLength--;
+}
+
+
+OPENMPT_NAMESPACE_END