mirror of https://github.com/libAthena/athena.git
236 lines
9.4 KiB
C++
236 lines
9.4 KiB
C++
#include "LZ77/LZLookupTable.hpp"
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#include "LZ77/LZType11.hpp"
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#include <athena/MemoryWriter.hpp>
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#include <string.h>
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LZType11::LZType11(atInt32 minimumOffset, atInt32 slidingWindow, atInt32 minimumMatch, atInt32 blockSize)
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: LZBase(minimumOffset, slidingWindow, minimumMatch, blockSize)
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{
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m_readAheadBuffer = (0xF + 0xFF + 0xFFFF + m_minMatch);
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m_lookupTable.setLookAheadWindow(m_readAheadBuffer);
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}
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atUint32 LZType11::compress(const atUint8* src, atUint8** dst, atUint32 srcLength)
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{
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athena::io::MemoryCopyWriter outbuff("tmp");
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if (srcLength > 0xFFFFFF) // If length is greater than 24 bits or 16 Megs
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{
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atUint32 encodeFlag = 0x11;
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athena::utility::LittleUint32(encodeFlag);
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athena::utility::LittleUint32(srcLength);//Filesize data is little endian
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outbuff.writeUint32(encodeFlag);
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outbuff.writeUint32(srcLength);
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}
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else
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{
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atUint32 encodeSize = (srcLength << 8) | (0x11);
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athena::utility::LittleUint32(encodeSize);
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outbuff.writeUint32(encodeSize);
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}
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atUint8* ptrStart = (atUint8*)src;
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atUint8* ptrEnd = (atUint8*)(src + srcLength);
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//At most their will be two bytes written if the bytes can be compressed. So if all bytes in the block can be compressed it would take blockSize*2 bytes
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atUint8* compressedBytes = new atUint8[m_blockSize * 2]; //Holds the compressed bytes yet to be written
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atUint8 maxTwoByteMatch = 0xF + 1;
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atUint8 minThreeByteMatch = maxTwoByteMatch + 1; //Minimum Three byte match is maximum TwoByte match + 1
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atUint16 maxThreeByteMatch = 0xFF + minThreeByteMatch;
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atUint16 minFourByteMatch = maxThreeByteMatch + 1; //Minimum Four byte match is maximum Three Byte match + 1
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atInt32 maxFourByteMatch = 0xFFFF + minFourByteMatch;
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/*
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Normaliazation Example: If MIN_MATCH is 3 then 3 gets mapped to 2 and 16 gets mapped to 15.
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17 gets mapped to 1 and 272 gets mapped to 255
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273 gets mapped to 0 and 65808 gets mapped to 65535
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A two byte match uses 4 bits
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A three byte match uses 8 bits
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A four byte match uses 16 bits
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In each case the offset uses 12 bits
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In the two byte case the length is normalized so that the first 4 bits are numbers between between 2 and 15
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In the three byte case the first 4 bits are 0000
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In the four byte case the first 4 bits a 0001
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*/
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while (ptrStart < ptrEnd)
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{
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atUint8 blockSize = 0;
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//In Binary represents 1 if byte is compressed or 0 if not compressed
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//For example 01001000 means that the second and fifth byte in the blockSize from the left is compressed
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atUint8* ptrBytes = compressedBytes;
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for (atInt32 i = 0; i < m_blockSize; i++)
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{
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//length_offset searchResult=Search(filedata,ptrStart,ptrEnd);
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LZLengthOffset searchResult = m_lookupTable.search(ptrStart, src, ptrEnd);
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//If the number of bytes to be compressed is at least the size of the Minimum match
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if (searchResult.length >= (atUint32)m_minMatch)
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{
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//Gotta swap the bytes since system is wii is big endian and most computers are little endian
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if (searchResult.length <= maxTwoByteMatch)
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{
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atUint16 lenOff = ((((searchResult.length - 1) & 0xF) << 12) | //Bits 15-12
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((searchResult.offset - 1) & 0xFFF) //Bits 11-0
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);
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athena::utility::BigUint16(lenOff);
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memcpy(ptrBytes, &lenOff, 2);
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ptrBytes += 2;
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}
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else if (searchResult.length <= maxThreeByteMatch)
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{
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atUint32 lenOff = ((((searchResult.length - minThreeByteMatch) & 0xFF) << 12) | //Bits 20-12
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((searchResult.offset - 1) & 0xFFF) //Bits 11-0
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);
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athena::utility::BigUint32(lenOff);
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memcpy(ptrBytes, (atUint8*)&lenOff + 1, 3); //Make sure to copy the lower 24 bits. 0x12345678- This statement copies 0x123456
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ptrBytes += 3;
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}
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else if (searchResult.length <= (atUint32)maxFourByteMatch)
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{
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atUint32 lenOff = ((1 << 28) | //Bits 31-28 Flag to say that this is four bytes
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(((searchResult.length - minFourByteMatch) & 0xFFFF) << 12) | //Bits 28-12
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((searchResult.offset - 1) & 0xFFF) //Bits 11-0
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);
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athena::utility::BigUint32(lenOff);
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memcpy(ptrBytes, &lenOff, 4);
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ptrBytes += 4;
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}
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ptrStart += searchResult.length;
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blockSize |= (1 << (7 - i));
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//Stores which of the next 8 bytes is compressed
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//bit 1 for compress and bit 0 for not compressed
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}
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else
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*ptrBytes++ = *ptrStart++;
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}
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outbuff.writeByte(blockSize);
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outbuff.writeUBytes(compressedBytes, (atUint64)(ptrBytes - compressedBytes));
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}
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delete []compressedBytes;
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compressedBytes = NULL;
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//Add zeros until the file is a multiple of 4
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while ((outbuff.position() % 4) != 0)
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outbuff.writeByte(0);
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*dst = outbuff.data();
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return (atUint32)outbuff.length();
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}
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atUint32 LZType11::decompress(const atUint8* src, atUint8** dst, atUint32 srcLength)
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{
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if (*(atUint8*)(src) != 0x11)
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return 0;
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atUint32 uncompressedLen = *(atUint32*)(src);
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athena::utility::LittleUint32(uncompressedLen);//The compressed file has the filesize encoded in little endian
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uncompressedLen = uncompressedLen >> 8; //First byte is the encode flag
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atUint32 currentOffset = 4;
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if (uncompressedLen == 0) //If the filesize var is zero then the true filesize is over 14MB and must be read in from the next 4 bytes
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{
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atUint32 filesize = *(atUint32*)(src + 4);
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filesize = athena::utility::LittleUint32(filesize);
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currentOffset += 4;
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}
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atUint8* uncompressedData = new atUint8[uncompressedLen];
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atUint8* outputPtr = uncompressedData;
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atUint8* outputEndPtr = uncompressedData + uncompressedLen;
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atUint8* inputPtr = (atUint8*)src + currentOffset;
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atUint8* inputEndPtr = (atUint8*)src + srcLength;
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LZLengthOffset decoding;
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atUint8 maxTwoByteMatch = 0xF + 1;
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atUint8 threeByteDenorm = maxTwoByteMatch + 1; //Amount to add to length when compression is 3 bytes
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atUint16 maxThreeByteMatch = 0xFF + threeByteDenorm;
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atUint16 fourByteDenorm = maxThreeByteMatch + 1;
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while (inputPtr < inputEndPtr && outputPtr < outputEndPtr)
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{
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atUint8 isCompressed = *inputPtr++;
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for (atInt32 i = 0; i < m_blockSize; i++)
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{
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//Checks to see if the next byte is compressed by looking
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//at its binary representation - E.g 10010000
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//This says that the first extracted byte and the four extracted byte is compressed
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if ((isCompressed >> (7 - i)) & 0x1)
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{
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atUint8 metaDataSize = *inputPtr >> 4; //Look at the top 4 bits
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if (metaDataSize >= 2) //Two Bytes of Length/Offset MetaData
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{
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atUint16 lenOff = 0;
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memcpy(&lenOff, inputPtr, 2);
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inputPtr += 2;
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athena::utility::BigUint16(lenOff);
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decoding.length = (lenOff >> 12) + 1;
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decoding.offset = (lenOff & 0xFFF) + 1;
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}
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else if (metaDataSize == 0) //Three Bytes of Length/Offset MetaData
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{
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atUint32 lenOff = 0;
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memcpy((atUint8*)&lenOff + 1, inputPtr, 3);
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inputPtr += 3;
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athena::utility::BigUint32(lenOff);
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decoding.length = (lenOff >> 12) + threeByteDenorm;
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decoding.offset = (lenOff & 0xFFF) + 1;
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}
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else if (metaDataSize == 1) //Four Bytes of Length/Offset MetaData
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{
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atUint32 lenOff = 0;
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memcpy(&lenOff, inputPtr, 4);
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inputPtr += 4;
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athena::utility::BigUint32(lenOff);
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decoding.length = ((lenOff >> 12) & 0xFFFF) + fourByteDenorm; //Gets rid of the Four byte flag
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decoding.offset = (lenOff & 0xFFF) + 1;
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}
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else
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{
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delete[] uncompressedData;
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uncompressedData = nullptr;
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return 0;
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}
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if ((outputPtr - decoding.offset) < uncompressedData) //If the offset to look for uncompressed is passed the current uncompresed data then the data is not compressed
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{
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delete []uncompressedData;
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return 0;
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}
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for (atUint32 j = 0; j < decoding.length; ++j)
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outputPtr[j] = (outputPtr - decoding.offset)[j];
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outputPtr += decoding.length;
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}
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else
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*outputPtr++ = *inputPtr++;
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if (!(inputPtr < inputEndPtr && outputPtr < outputEndPtr))
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break;
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}
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}
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*dst = uncompressedData;
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return uncompressedLen;
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}
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