blob: b0d8785259025eb467a5fa86d19dd561a62e94a4 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
|
#include "util.h"
void hexdump(const void *vbuf, size_t len) {
const uint8_t *buf = vbuf;
for (size_t i = 0; i < len; i += 16) {
printf("%08x ", i);
for (size_t j = i; j < i + 8 && j < len; j++)
printf("%02x ", buf[j]);
printf(" ");
for (size_t j = i + 8; j < i + 16 && j < len; j++)
printf("%02x ", buf[j]);
printf("\n");
}
}
/* https://www.w3.org/TR/PNG/#D-CRCAppendix */
static uint32_t crc_table[256];
uint32_t crc32(const uint8_t *buf, size_t len) {
if (!crc_table[1]) {
for (int i = 0; i < 256; i++) {
uint32_t c = i;
for (int j = 0; j < 8; j++)
c = ((c&1) ? 0xedb88320 : 0) ^ (c >> 1);
crc_table[i] = c;
}
}
uint32_t c = 0xFFFFFFFF;
for (size_t i = 0; i < len; i++)
c = crc_table[(c ^ buf[i]) & 0xff] ^ (c >> 8);
return ~c;
}
|
