winamp/Src/external_dependencies/openmpt-trunk/soundlib/ITCompression.h
2024-09-24 14:54:57 +02:00

102 lines
3.6 KiB
C++

/*
* ITCompression.h
* ---------------
* 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.
*/
#pragma once
#include "openmpt/all/BuildSettings.hpp"
#include <vector>
#include <iosfwd>
#include "Snd_defs.h"
#include "BitReader.h"
OPENMPT_NAMESPACE_BEGIN
struct ModSample;
class ITCompression
{
public:
ITCompression(const ModSample &sample, bool it215, std::ostream *f, SmpLength maxLength = 0);
size_t GetCompressedSize() const { return packedTotalLength; }
static constexpr size_t bufferSize = 2 + 0xFFFF; // Our output buffer can't be longer than this.
static constexpr size_t blockSize = 0x8000; // Block size (in bytes) in which samples are being processed
protected:
std::vector<int8> bwt; // Bit width table for each sampling point
std::vector<uint8> packedData; // Compressed data for current sample block
std::ostream *file = nullptr; // File to which compressed data will be written (can be nullptr if you only want to find out the sample size)
std::vector<int8> sampleData8; // Pre-processed sample data for currently compressed sample block
std::vector<int16> sampleData16; // Pre-processed sample data for currently compressed sample block
const ModSample &mptSample; // Sample that is being processed
size_t packedLength = 0; // Size of currently compressed sample block
size_t packedTotalLength = 0; // Size of all compressed data so far
SmpLength baseLength = 0; // Length of the currently compressed sample block (in samples)
// Bit writer
int8 bitPos = 0; // Current bit position in this byte
int8 remBits = 0; // Remaining bits in this byte
uint8 byteVal = 0; // Current byte value to be written
const bool is215; // Use IT2.15 compression (double deltas)
template<typename Properties>
void Compress(const typename Properties::sample_t *mptSampleData, SmpLength maxLength);
template<typename T>
static void CopySample(T *target, const T *source, SmpLength offset, SmpLength length, SmpLength skip);
template<typename T>
void Deltafy(T *sampleData);
template<typename Properties>
void CompressBlock(const typename Properties::sample_t *data, SmpLength offset, SmpLength actualLength, typename Properties::sample_t *sampleData);
static int8 GetWidthChangeSize(int8 w, bool is16);
template<typename Properties>
void SquishRecurse(int8 sWidth, int8 lWidth, int8 rWidth, int8 width, SmpLength offset, SmpLength length, const typename Properties::sample_t *sampleData);
static int8 ConvertWidth(int8 curWidth, int8 newWidth);
void WriteBits(int8 width, int v);
void WriteByte(uint8 v);
};
class ITDecompression
{
public:
ITDecompression(FileReader &file, ModSample &sample, bool it215);
protected:
BitReader bitFile;
ModSample &mptSample; // Sample that is being processed
SmpLength writtenSamples = 0; // Number of samples so far written on this channel
SmpLength writePos = 0; // Absolut write position in sample (for stereo samples)
SmpLength curLength = 0; // Length of currently processed block
unsigned int mem1 = 0, mem2 = 0; // Integrator memory
const bool is215; // Use IT2.15 compression (double deltas)
template<typename Properties>
void Uncompress(typename Properties::sample_t *target);
static void ChangeWidth(int &curWidth, int width);
template<typename Properties>
void Write(int v, int topbit, typename Properties::sample_t *target);
};
OPENMPT_NAMESPACE_END