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