411 lines
10 KiB
C++
411 lines
10 KiB
C++
/*
|
|
* 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 "../common/misc_util.h"
|
|
#include "../common/mptIO.h"
|
|
#include "ModSample.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) <= CountOf(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) < CountOf(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
|