mirror of
https://github.com/pfusik/zlib6502.git
synced 2024-06-03 11:29:39 +00:00
79 lines
1.5 KiB
C
79 lines
1.5 KiB
C
// gzip2deflate by Piotr Fusik <fox@scene.pl>
|
|
// http://xasm.atari.org
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#ifdef __WIN32
|
|
#include <fcntl.h>
|
|
#endif
|
|
|
|
static int get_byte(void)
|
|
{
|
|
int b = getchar();
|
|
if (b == EOF) {
|
|
fputs("gzip2deflate: unexpected end of stream\n", stderr);
|
|
exit(1);
|
|
}
|
|
return b;
|
|
}
|
|
|
|
static void skip_bytes(int n)
|
|
{
|
|
while (--n >= 0)
|
|
get_byte();
|
|
}
|
|
|
|
static void skip_string(void)
|
|
{
|
|
while (get_byte() != 0);
|
|
}
|
|
|
|
int main (int argc, char *argv[])
|
|
{
|
|
int flg;
|
|
char buf[8 + 4096];
|
|
size_t len;
|
|
#ifdef __WIN32
|
|
_setmode(_fileno(stdin), _O_BINARY);
|
|
_setmode(_fileno(stdout), _O_BINARY);
|
|
#endif
|
|
if (get_byte() != 0x1f || get_byte() != 0x8b || get_byte() != 8) {
|
|
fputs("gzip2deflate: not a gzip file on stdin\n", stderr);
|
|
return 1;
|
|
}
|
|
flg = get_byte();
|
|
skip_bytes(6);
|
|
if ((flg & 4) != 0) {
|
|
int xlen = get_byte();
|
|
xlen += get_byte() << 8;
|
|
skip_bytes(xlen);
|
|
}
|
|
if ((flg & 8) != 0)
|
|
skip_string();
|
|
if ((flg & 16) != 0)
|
|
skip_string();
|
|
if ((flg & 2) != 0)
|
|
skip_bytes(2);
|
|
/* copy everything except the last 8 bytes */
|
|
len = 0;
|
|
for (;;) {
|
|
len += fread(buf + len, 1, sizeof(buf) - len, stdin);
|
|
if (len != sizeof(buf))
|
|
break;
|
|
fwrite(buf, 1, sizeof(buf) - 8, stdout);
|
|
memcpy(buf, buf + sizeof(buf) - 8, 8);
|
|
len = 8;
|
|
}
|
|
if (ferror(stdin)) {
|
|
fputs("gzip2deflate: read error\n", stderr);
|
|
return 1;
|
|
}
|
|
if (len < 8) {
|
|
fputs("gzip2deflate: unexpected end of stream\n", stderr);
|
|
return 1;
|
|
}
|
|
fwrite(buf, 1, len - 8, stdout);
|
|
return 0;
|
|
}
|