145 lines
3.3 KiB
C
145 lines
3.3 KiB
C
/***************************************************************************
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* Copyright (C) 2010
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* by Dimok
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any
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* damages arising from the use of this software.
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*
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* Permission is granted to anyone to use this software for any
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* purpose, including commercial applications, and to alter it and
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* redistribute it freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you
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* must not claim that you wrote the original software. If you use
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* this software in a product, an acknowledgment in the product
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* documentation would be appreciated but is not required.
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*
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* 2. Altered source versions must be plainly marked as such, and
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* must not be misrepresented as being the original software.
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*
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* 3. This notice may not be removed or altered from any source
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* distribution.
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*
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* for WiiXplorer 2010
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***************************************************************************/
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#include <malloc.h>
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#include <string.h>
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#include "uncompress.h"
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#include "lz77.h"
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u8 * uncompressLZ77(const u8 *inBuf, u32 inLength, u32 * size)
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{
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if(!inBuf)
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return NULL;
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u8 *buffer = NULL;
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if (*((const u32 *)inBuf) != 0x4C5A3737 /*"LZ77"*/)
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return NULL;
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decompressLZ77content( (u8*)inBuf + 4, inLength - 4, &buffer, size);
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return buffer;
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}
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//Thanks to _demo_ for this function
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//src points to the yaz0 source data (to the "real" source data, not at the header!)
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//dst points to a buffer uncompressedSize bytes large (you get uncompressedSize from
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//the second 4 bytes in the Yaz0 header).
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void uncompressYaz0(const u8* srcBuf, u8* dst, int uncompressedSize)
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{
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if(!srcBuf || !dst)
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return;
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const u8 * src = srcBuf;
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if(*((u32*)src) == 'Yaz0')
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{
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src += sizeof(Yaz0_Header);
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}
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int srcPlace = 0, dstPlace = 0; //current read/write positions
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u32 validBitCount = 0; //number of valid bits left in "code" byte
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u8 currCodeByte = 0;
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while(dstPlace < uncompressedSize)
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{
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//read new "code" byte if the current one is used up
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if(validBitCount == 0)
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{
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currCodeByte = src[srcPlace];
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++srcPlace;
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validBitCount = 8;
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}
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if((currCodeByte & 0x80) != 0)
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{
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//straight copy
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dst[dstPlace] = src[srcPlace];
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dstPlace++;
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srcPlace++;
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}
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else
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{
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//RLE part
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u8 byte1 = src[srcPlace];
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u8 byte2 = src[srcPlace + 1];
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srcPlace += 2;
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u32 dist = ((byte1 & 0xF) << 8) | byte2;
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u32 copySource = dstPlace - (dist + 1);
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u32 numBytes = byte1 >> 4;
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if(numBytes == 0)
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{
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numBytes = src[srcPlace] + 0x12;
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srcPlace++;
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}
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else
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numBytes += 2;
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//copy run
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u32 i = 0;
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for(i = 0; i < numBytes; ++i)
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{
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dst[dstPlace] = dst[copySource];
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copySource++;
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dstPlace++;
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}
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}
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//use next bit from "code" byte
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currCodeByte <<= 1;
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validBitCount-=1;
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}
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}
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u32 CheckIMD5Type(const u8 * buffer, int length)
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{
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if(*((u32 *) buffer) != 'IMD5')
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{
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return *((u32 *) buffer);
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}
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const u8 * file = buffer+32;
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if(*((u32 *) file) != 'LZ77')
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{
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return *((u32 *) file);
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}
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u32 uncSize = 0;
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u8 * uncompressed_data = uncompressLZ77(file, length-32, &uncSize);
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if(!uncompressed_data)
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return 0;
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u32 * magic = (u32 *) uncompressed_data;
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u32 Type = magic[0];
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free(uncompressed_data);
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return Type;
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}
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