git.zerfleddert.de Git - rsbs2/blob - src/rsb-crc.c

   1 #include <stdio.h>
   2 #include <stdint.h>
   3
   4 #define POLY 0x04c11db7
   5
   6 uint32_t rsb_crc(uint32_t r11_crc, uint8_t *r10_buf, uint32_t r14_len) {
   7         uint32_t r6_pos = 0;
   8         uint32_t r3_data;
   9         int32_t r5_bit;
  10
  11         while (r6_pos < r14_len) {
  12                 r3_data = (*(r6_pos+r10_buf)) << 24;
  13                 r11_crc = r11_crc ^ r3_data;
  14
  15                 r5_bit = 8;
  16
  17                 do {
  18                         r3_data = r11_crc & 0x80000000;
  19
  20                         if (r3_data != 0) {
  21                                 r3_data = r11_crc << 1;
  22                                 r11_crc = r3_data ^ POLY;
  23                         } else {
  24                                 r11_crc = r11_crc << 1;
  25                         }
  26                         r5_bit--;
  27                 } while (r5_bit);
  28
  29                 r6_pos++;
  30         }
  31
  32         return r11_crc;
  33 }
  34
  35 uint32_t rsb_crc2(uint8_t *r0_buf, uint32_t r1_buflen, uint32_t r2_magic, uint32_t *crc_out) {
  36         uint32_t r4_len;
  37         uint32_t file_crc;
  38
  39         r4_len = *(uint32_t*)(r0_buf + 0x20);
  40
  41         if (*((uint32_t*)(r0_buf + 0x24)) != r2_magic)
  42                 return 2; /* MAGIC does not match */
  43
  44         if (r1_buflen < r4_len)
  45                 return 3; /* image to small */
  46
  47         *crc_out = ~rsb_crc(~0x0, r0_buf, r4_len);
  48
  49         file_crc = *((uint32_t*)(r0_buf + r4_len));
  50
  51         if (file_crc != *crc_out)
  52                 return 4;
  53
  54         return 0;
  55 }