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/*
scanlzma, scan for lzma compressed data in stdin and echo it to stdout.
Copyright (C) 2006 Timo Lindfors
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 of the License, 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.
*/
/* Usage example:
$ wget http://www.wifi-shop.cz/Files/produkty/wa2204/wa2204av1.4.1.zip
$ unzip wa2204av1.4.1.zip
$ gcc scanlzma.c -o scanlzma -Wall
$ ./scanlzma 0 < WA2204-FW1.4.1/linux-1.4.bin | lzma -c -d | strings | grep -i "copyright"
UpdateDD version 2.5, Copyright (C) 2005 Philipp Benner.
Copyright (C) 2005 Philipp Benner.
Copyright (C) 2005 Philipp Benner.
mawk 1.3%s%s %s, Copyright (C) Michael D. Brennan
# Copyright (C) 1998, 1999, 2001 Henry Spencer.
...
*/
/* LZMA compressed file format */
/* --------------------------- */
/* Offset Size Description */
/* 0 1 Special LZMA properties for compressed data */
/* 1 4 Dictionary size (little endian) */
/* 5 8 Uncompressed size (little endian). -1 means unknown size */
/* 13 Compressed data */
#define BUFSIZE 4096
int find_lzma_header(unsigned char *buf) {
return (buf[0] < 0xE1
&& buf[0] == 0x5d
&& buf[4] < 0x20
&& (memcmp (buf + 10 , "\x00\x00\x00", 3) == 0
|| (memcmp (buf + 5, "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF", 8) == 0)));
}
int main(int argc, char *argv[]) {
char buf[BUFSIZE];
int ret, i, numlzma, blocks=0;
if (argc != 2) {
printf("usage: %s numlzma < infile | lzma -c -d > outfile\n"
"where numlzma is index of lzma file to extract, starting from zero.\n",
argv[0]);
exit(1);
}
numlzma = atoi(argv[1]);
for (;;) {
/* Read data. */
ret = fread(buf, BUFSIZE, 1, stdin);
if (ret != 1)
break;
/* Scan for signature. */
for (i = 0; i<BUFSIZE-23; i++) {
if (find_lzma_header(buf+i) && numlzma-- <= 0) {
fwrite(buf+i, (BUFSIZE-i), 1, stdout);
for (;;) {
int ch;
ch = getchar();
if (ch == EOF)
exit(0);
putchar(ch);
}
}
}
blocks++;
}
return 1;
}
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