/* FileHandler - General-purpose file handling library for Niotso refpack_dec.c - Copyright (c) 2011 Niotso Project Author(s): Fatbag Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include #include int RefPackDecompress(const uint8_t *__restrict CompressedData, size_t CompressedSize, uint8_t *__restrict DecompressedData, size_t DecompressedSize, unsigned HNSV){ unsigned datawritten = 0; int stopflag = 0, StopFlagData; if(HNSV == 0) HNSV = 0xFB; /* EA default */ if (HNSV >= 0xFF) StopFlagData = 0x1F; else if(HNSV >= 0xFE) StopFlagData = 0x00; else if(HNSV >= 0xFD) StopFlagData = 0x01; else if(HNSV >= 0xFB) StopFlagData = 0x03; else if(HNSV >= 0xF7) StopFlagData = 0x07; else StopFlagData = 0x0F; while(CompressedSize > 0 && !stopflag){ unsigned ProceedingDataLength, ReferencedDataLength, ReferencedDataOffset; unsigned currentbyte = *(CompressedData++); CompressedSize--; /**** ** Fetch the opcode */ /* The first byte determines the size of the entire opcode. */ if(currentbyte <= 0x7F){ /* 2 bytes */ if(CompressedSize < 1) return 0; CompressedSize -= 1; /* First byte */ ProceedingDataLength = currentbyte & 0x03; ReferencedDataLength = ((currentbyte & 0x1C) >> 2) + 3; ReferencedDataOffset = (currentbyte & 0x60) << 3; /* Second byte */ currentbyte = *(CompressedData++); ReferencedDataOffset += currentbyte; }else if(currentbyte <= 0xBF){ /* 3 bytes */ if(CompressedSize < 2) return 0; CompressedSize -= 2; /* First byte */ ReferencedDataLength = (currentbyte & 0x3F) + 4; /* Second byte */ currentbyte = *(CompressedData++); ProceedingDataLength = (currentbyte & 0xC0) >> 6; ReferencedDataOffset = (currentbyte & 0x3F) << 8; /* Third byte */ currentbyte = *(CompressedData++); ReferencedDataOffset += currentbyte; }else if(currentbyte <= 0xDF){ /* 4 bytes */ if(CompressedSize < 3) return 0; CompressedSize -= 3; /* First byte */ ProceedingDataLength = currentbyte & 0x03; ReferencedDataLength = ((currentbyte & 0x0C) << 6) + 5; ReferencedDataOffset = (currentbyte & 0x10) << 12; /* Second byte */ currentbyte = *(CompressedData++); ReferencedDataOffset += currentbyte << 8; /* Third byte */ currentbyte = *(CompressedData++); ReferencedDataOffset += currentbyte; /* Fourth byte */ currentbyte = *(CompressedData++); ReferencedDataLength += currentbyte; }else{ /* 1 byte: Two different opcode types fall into this category */ if(currentbyte <= HNSV){ ProceedingDataLength = ((currentbyte & 0x1F) + 1) << 2; }else{ ProceedingDataLength = currentbyte & StopFlagData; stopflag++; } ReferencedDataLength = 0; } /**** ** Copy proceeding data */ if(ProceedingDataLength != 0){ if(ProceedingDataLength > CompressedSize || ProceedingDataLength > DecompressedSize) return 0; memcpy(DecompressedData, CompressedData, ProceedingDataLength); DecompressedSize -= ProceedingDataLength; CompressedSize -= ProceedingDataLength; datawritten += ProceedingDataLength; DecompressedData += ProceedingDataLength; CompressedData += ProceedingDataLength; } /**** ** Copy referenced data */ if(ReferencedDataLength != 0){ /* It is possible that the offset specified does not provide for a large enough buffer to copy all at once from. This event would be caused when the referenced data offset is set smaller than the referenced data length. When this occurs, the decoder is to repeatedly copy/paste the referenced data until the length is satisfied. We will do this in a way so that we call memcpy ceil(log2(N)) times instead of N times. */ ReferencedDataOffset++; if(ReferencedDataLength > DecompressedSize || ReferencedDataOffset > datawritten) return 0; DecompressedSize -= ReferencedDataLength; datawritten += ReferencedDataLength; if(ReferencedDataOffset == 1){ memset(DecompressedData, *(DecompressedData-1), ReferencedDataLength); DecompressedData += ReferencedDataLength; }else{ unsigned copylength = (ReferencedDataOffset < ReferencedDataLength) ? ReferencedDataOffset : ReferencedDataLength; uint8_t *__restrict copysource = DecompressedData; memcpy(DecompressedData, DecompressedData-ReferencedDataOffset, copylength); DecompressedData += copylength; ReferencedDataLength -= copylength; while(ReferencedDataLength){ if(copylength > ReferencedDataLength) copylength = ReferencedDataLength; memcpy(DecompressedData, copysource, copylength); DecompressedData += copylength; ReferencedDataLength -= copylength; if(!(copylength&0x80000000)) copylength <<= 1; } } } } return (stopflag && !CompressedSize && !DecompressedSize); }