88 lines
2.5 KiB
C
88 lines
2.5 KiB
C
//
|
|
// Created by bruno on 4/29/25.
|
|
//
|
|
|
|
#include <string.h>
|
|
#include <stdio.h>
|
|
#include <stdint-gcc.h>
|
|
#include "base.h"
|
|
|
|
// Base64 decoding table
|
|
const unsigned char dtable[256] = {
|
|
['A'] = 0, ['B'] = 1, ['C'] = 2, ['D'] = 3,
|
|
['E'] = 4, ['F'] = 5, ['G'] = 6, ['H'] = 7,
|
|
['I'] = 8, ['J'] = 9, ['K'] = 10, ['L'] = 11,
|
|
['M'] = 12, ['N'] = 13, ['O'] = 14, ['P'] = 15,
|
|
['Q'] = 16, ['R'] = 17, ['S'] = 18, ['T'] = 19,
|
|
['U'] = 20, ['V'] = 21, ['W'] = 22, ['X'] = 23,
|
|
['Y'] = 24, ['Z'] = 25,
|
|
['a'] = 26, ['b'] = 27, ['c'] = 28, ['d'] = 29,
|
|
['e'] = 30, ['f'] = 31, ['g'] = 32, ['h'] = 33,
|
|
['i'] = 34, ['j'] = 35, ['k'] = 36, ['l'] = 37,
|
|
['m'] = 38, ['n'] = 39, ['o'] = 40, ['p'] = 41,
|
|
['q'] = 42, ['r'] = 43, ['s'] = 44, ['t'] = 45,
|
|
['u'] = 46, ['v'] = 47, ['w'] = 48, ['x'] = 49,
|
|
['y'] = 50, ['z'] = 51,
|
|
['0'] = 52, ['1'] = 53, ['2'] = 54, ['3'] = 55,
|
|
['4'] = 56, ['5'] = 57, ['6'] = 58, ['7'] = 59,
|
|
['8'] = 60, ['9'] = 61, ['+'] = 62, ['/'] = 63,
|
|
};
|
|
|
|
|
|
int base64_decode(const char *in, unsigned char *out, size_t *out_len) {
|
|
size_t len = strlen(in);
|
|
size_t i, j;
|
|
unsigned char a, b, c, d;
|
|
|
|
if (len % 4 != 0) return -1;
|
|
|
|
for (i = 0, j = 0; i < len; i += 4) {
|
|
a = dtable[(unsigned char)in[i]];
|
|
b = dtable[(unsigned char)in[i+1]];
|
|
c = dtable[(unsigned char)in[i+2]];
|
|
d = dtable[(unsigned char)in[i+3]];
|
|
|
|
out[j++] = (a << 2) | (b >> 4);
|
|
if (in[i+2] != '=') {
|
|
out[j++] = (b << 4) | (c >> 2);
|
|
if (in[i+3] != '=')
|
|
out[j++] = (c << 6) | d;
|
|
}
|
|
}
|
|
*out_len = j;
|
|
return 0;
|
|
}
|
|
|
|
void hex_dump(const unsigned char *data, size_t len) {
|
|
for (size_t i = 0; i < len; i++) {
|
|
printf("%02X ", data[i]);
|
|
if ((i + 1) % 16 == 0)
|
|
printf("\n");
|
|
}
|
|
printf("\n");
|
|
}
|
|
|
|
static uint32_t crc32_table[256];
|
|
|
|
// Call this once before computing CRCs
|
|
void init_crc32_table(void) {
|
|
uint32_t poly = 0xEDB88320; // reversed polynomial of 0x04C11DB7
|
|
for (uint32_t i = 0; i < 256; i++) {
|
|
uint32_t crc = i;
|
|
for (uint8_t j = 0; j < 8; j++) {
|
|
if (crc & 1)
|
|
crc = (crc >> 1) ^ poly;
|
|
else
|
|
crc >>= 1;
|
|
}
|
|
crc32_table[i] = crc;
|
|
}
|
|
}
|
|
|
|
uint32_t crc32_le(uint32_t crc, const uint8_t *buf, size_t len) {
|
|
crc = ~crc;
|
|
while (len--) {
|
|
crc = crc32_table[(crc ^ *buf++) & 0xFF] ^ (crc >> 8);
|
|
}
|
|
return ~crc;
|
|
} |