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/*
* Copyright 2009 Luc Verhaegen <libv@skynet.be>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include "lzss_extract.h"
static inline int
LZSSBufferWrite(int fd, unsigned char *Buffer, int *BufferCount, unsigned char value)
{
Buffer[*BufferCount] = value;
*BufferCount += 1;
if (*BufferCount == 0x1000) {
if (write(fd, Buffer, 0x1000) != 0x1000) {
fprintf(stderr, "Error writing to output file: %s",
strerror(errno));
return 1;
}
*BufferCount = 0;
}
return 0;
}
int
LZSSExtract(unsigned char *Input, int InputSize, int fd)
{
unsigned char Buffer[0x1000];
unsigned short BitBuffer = 0;
int i = 0, k, BitCount = 8, BufferCount = 0;
while (i < InputSize) {
if (BitCount == 8) {
BitBuffer = Input[i];
BitCount = -1;
} else if ((BitBuffer >> BitCount) & 0x01) {
if (LZSSBufferWrite(fd, Buffer, &BufferCount, Input[i]))
return 1;
} else if ((i + 1) < InputSize) {
int offset = ((Input[i] | ((Input[i + 1] & 0xF0) << 4)) - 0xFEE) & 0xFFF;
int length = (Input[i + 1] & 0x0F) + 3;
for (k = 0; k < length; k++) {
if (LZSSBufferWrite(fd, Buffer, &BufferCount, Buffer[(offset + k) & 0xFFF]))
return 1;
}
i++;
} else {
fprintf(stderr, "Error: requesting data beyond end of input file.\n");
return 1;
}
i++;
BitCount++;
}
if (BufferCount) {
if (write(fd, Buffer, BufferCount) != BufferCount) {
fprintf(stderr, "Error writing to output file: %s",
strerror(errno));
return 1;
}
}
return 0;
}
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