hackaton2019

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define TARGET_NAME_ENCEDO "EncedoKey"
// uncomment to add support for digital code signature using ED25519
//#define  ED25519_SUPPORT

#ifdef ED25519_SUPPORT
#include "ED25519/sha512.h"
#include "ED25519/ed25519.h"

/*
To build:
1. download ED25519 code from https://github.com/encedo/ed25519 or https://github.com/orlp/ed25519 to folder ED25519
2. compile gcc hex2dfu.c ED25519/*.c -o hex2dfu.exe

*/

#endif

void print_help(void);
int hex2bin(unsigned char* obuf, const char* ibuf, int len);
int check_checksum(unsigned char* inbuf, int len);
unsigned char* ihex2bin_buf(unsigned int* start_address, int* dst_len, FILE* inFile);

//uint32_t crc32(uint32_t crc, const void *buf, size_t size);
unsigned int crc32(unsigned int crc, const void* buf, size_t size);

//efab5b0739a834bac702aeb5cd08ffe227908faaae501f910e7e07d8d41fbb06
int main(int argc, char** argv)
{
    int i, c, vid = 0x0483, pid = 0xdf11, ver = 0xffff;
    char *tar0 = NULL, *tar0_lab = NULL, *out_fn = NULL;
    FILE *inFile, *outFile;
    unsigned char json_output = 0;

#ifdef ED25519_SUPPORT
    unsigned char hash_buf[64];
    sha512_context hash;
    unsigned char* ed25519_secret = NULL;
    unsigned char *ed25519_public = NULL, ed25519_public_add = 0;
    unsigned char public_key[32], private_key[64], signature[64], public_key_publisher[32];
#endif

    unsigned int tar0_start_address;
    int tar0_len;
    unsigned char* tar0_buf;

    unsigned char* dfu;
    int dfu_len;
    unsigned int crc = 0, tmp, add_crc32 = 0;

    opterr = 0;
    while ((c = getopt(argc, argv, "hv:p:d:i:l:o:c:S:P:eJ")) != -1) {
        switch (c) {
        case 'J':
            json_output = 1;
            break;
        case 'i': //target0 input file name
            tar0 = optarg;
            break;
        case 'l': //target0 label
            tar0_lab = optarg;
            break;
        case 'p': //PID
            pid = strtol(optarg, NULL, 16);
            break;
        case 'v': //VID
            vid = strtol(optarg, NULL, 16);
            break;
        case 'd': //device version
            ver = strtol(optarg, NULL, 16);
            break;
        case 'c': //place crc32 at this address
            add_crc32 = strtol(optarg, NULL, 16);
            break;
        case 'S': //ED25519 secret (signing key), hex
#ifndef ED25519_SUPPORT
            fprintf(stderr, "Code signing not supported!\n");
            return 1;
#else
            ed25519_secret = optarg;
#endif
            break;
        case 'P': //ED25519 publisher public, hex
#ifndef ED25519_SUPPORT
            fprintf(stderr, "Code signing not supported!\n");
            return 1;
#else
            ed25519_public = optarg;
#endif
            break;
        case 'e':
#ifndef ED25519_SUPPORT
            fprintf(stderr, "Code signing not supported!\n");
            return 1;
#else
            ed25519_public_add = 1;
#endif
            break;
        case 'o': //output file name
            out_fn = optarg;
            break;
        case 'h':
            print_help();
            break;
        case '?':
            fprintf(stderr, "Parameter(s) parsing  failed!\n");
            return 1;
        default:
            break;
        }
    }

    if (!tar0) {
        perror("No input file specifed.\n");
        return 0;
    }

    if (!out_fn) {
        perror("No output file specifed.\n");
        return 0;
    }

#ifdef ED25519_SUPPORT
    if (ed25519_secret) {
        c = hex2bin(ed25519_secret, ed25519_secret, strlen(ed25519_secret));
        if (c != 32) {
            perror("ED25519 'secret' have to be 32bytes long.\n");
            return 0;
        }

        ed25519_create_keypair(public_key, private_key, ed25519_secret);

        if (ed25519_public) {
            c = hex2bin(public_key_publisher, ed25519_public, strlen(ed25519_public));
            if (c != 32) {
                perror("ED25519 'public' have to be 32bytes long.\n");
                return 0;
            }
        } else {
            memmove(public_key_publisher, public_key, 32);
        }
    }
#endif

    inFile = fopen(tar0, "r");
    tar0_buf = ihex2bin_buf(&tar0_start_address, &tar0_len, inFile);

    fclose(inFile);
    if (tar0_buf && (tar0_len > 0)) {
        if ((add_crc32 > 0) && (add_crc32 < (tar0_start_address + tar0_len - 256))) { //-c request CRC32 placement at given address
            add_crc32 -= tar0_start_address;
            tar0_buf[add_crc32 + 4] = tar0_len >> 0 & 0xFF; //binary code length first(little endian)
            tar0_buf[add_crc32 + 5] = tar0_len >> 8 & 0xFF;
            tar0_buf[add_crc32 + 6] = tar0_len >> 16 & 0xFF;
            tar0_buf[add_crc32 + 7] = tar0_len >> 24 & 0xFF;
#ifdef ED25519_SUPPORT
            if (ed25519_secret) {
                sha512_init(&hash);
                sha512_update(&hash, tar0_buf, add_crc32);
                sha512_update(&hash, tar0_buf + add_crc32 + 256, tar0_len - (add_crc32 + 256));
                sha512_final(&hash, hash_buf);

                ed25519_sign(signature, hash_buf, 64, public_key, private_key);
                memmove(tar0_buf + add_crc32 + 0x10, signature, 64);
                memmove(tar0_buf + add_crc32 + 0x10 + 64, public_key, 32);

                if (ed25519_public_add) {
                    memmove(tar0_buf + add_crc32 + 0x10 + 64 + 32, public_key_publisher, 32);
                }
            }
#endif
            crc = crc32(0, tar0_buf, add_crc32); //calc CRC upto placement address
            crc = crc32(crc, tar0_buf + add_crc32 + 4, tar0_len - (add_crc32 + 4)); //calc the rest of - starting from placement+4 up to end
            tar0_buf[add_crc32] = crc >> 0 & 0xFF; //CRC placement (little endian)
            tar0_buf[add_crc32 + 1] = crc >> 8 & 0xFF;
            tar0_buf[add_crc32 + 2] = crc >> 16 & 0xFF;
            tar0_buf[add_crc32 + 3] = crc >> 24 & 0xFF;
        }

        dfu_len = 11 + 274 + 8 + tar0_len + 16;
        dfu = calloc(1, dfu_len);
        if (dfu) {
            //DFU Suffix
            memmove(dfu, "DfuSe", 5); //szSignature
            dfu[5] = 0x01; //bVersion
            tmp = dfu_len - 0x10;
            dfu[6] = (unsigned char)(tmp & 0xFF); //DFUImageSize               (except Prefix!)
            dfu[7] = (unsigned char)(tmp >> 8 & 0xFF);
            dfu[8] = (unsigned char)(tmp >> 16 & 0xFF);
            dfu[9] = (unsigned char)(tmp >> 24 & 0xFF);
            dfu[10] = 1; //bTargets

            //DFU Image
            c = 11;
            memmove(dfu + c, "Target", 6); //szSignature 'Target'
            c += 6;
            dfu[c++] = 0x00; //bAlternateSettings        //to check
            if (tar0_lab) {
                dfu[c] = 0x01; //bTargetNamed
                memmove(dfu + c + 4, tar0_lab, strlen(tar0_lab) > 254 ? 254 : strlen(tar0_lab)); //szTargetName
            } else {
                dfu[c] = 0x01; //place default target name
                memmove(dfu + c + 4, TARGET_NAME_ENCEDO, strlen(TARGET_NAME_ENCEDO));
            }
            c += 259;
            tmp = 8 + tar0_len; //ImageElement length (8+bin_data)
            dfu[c++] = tmp & 0xFF; //dwTargetSize
            dfu[c++] = tmp >> 8 & 0xFF;
            dfu[c++] = tmp >> 16 & 0xFF;
            dfu[c++] = tmp >> 24 & 0xFF;
            dfu[c] = 0x01; //dwNbElements
            c += 4;

            //Image Element
            dfu[c++] = tar0_start_address & 0xFF; //dwElementAddress
            dfu[c++] = tar0_start_address >> 8 & 0xFF;
            dfu[c++] = tar0_start_address >> 16 & 0xFF;
            dfu[c++] = tar0_start_address >> 24 & 0xFF;
            dfu[c++] = tar0_len & 0xFF; //dwElementSize
            dfu[c++] = tar0_len >> 8 & 0xFF;
            dfu[c++] = tar0_len >> 16 & 0xFF;
            dfu[c++] = tar0_len >> 24 & 0xFF;
            memmove(dfu + c, tar0_buf, tar0_len);

            //DFU Suffix
            c = dfu_len - 16;
            dfu[c++] = ver & 0xFF; //bcdDeviceLo
            dfu[c++] = ver >> 8 & 0xFF;
            dfu[c++] = pid & 0xFF; //idProductLo
            dfu[c++] = pid >> 8 & 0xFF;
            dfu[c++] = vid & 0xFF; //idVendorLo
            dfu[c++] = vid >> 8 & 0xFF;
            dfu[c++] = 0x1A; //bcdDFULo
            dfu[c++] = 0x01;
            dfu[c++] = 'U'; //ucDfuSignature
            dfu[c++] = 'F';
            dfu[c++] = 'D';
            dfu[c++] = 16; //bLength
            crc = 0xFFFFFFFF & -crc32(0, dfu, c) - 1;
            dfu[c++] = crc >> 0 & 0xFF; //dwCRC
            dfu[c++] = crc >> 8 & 0xFF;
            dfu[c++] = crc >> 16 & 0xFF;
            dfu[c++] = crc >> 24 & 0xFF;

            //write DFU to file
            outFile = fopen(out_fn, "wb");
            c = fwrite(dfu, dfu_len, 1, outFile);
            fclose(outFile);
            if (c != 1) {
                printf("error: write to output file\n");
            }
            if (json_output) {
                printf("{\"code_address\":\"0x%08x\"", tar0_start_address);
                printf(",\"code_length\":\"0x%08x\"", tar0_len);
                printf(",\"meta_address\":\"0x%08x\"", add_crc32 + tar0_start_address);
#ifdef ED25519_SUPPORT
                if (ed25519_secret) {
                    printf(",\"sha512\":\"");
                    for (c = 0; c < 64; c++) {
                        printf("%02x", (unsigned char)hash_buf[c]);
                    }
                    printf("\"");

                    printf(",\"signature_pubkey\":\"");
                    for (c = 0; c < 32; c++) {
                        printf("%02x", (unsigned char)public_key[c]);
                    }
                    printf("\"");

                    printf(",\"signature\":\"");
                    for (c = 0; c < 64; c++) {
                        printf("%02x", (unsigned char)signature[c]);
                    }
                    printf("\"");

                    if (ed25519_public_add) {
                        printf(",\"publisher_pubkey\":\"");
                        for (c = 0; c < 32; c++) {
                            printf("%02x", (unsigned char)public_key_publisher[c]);
                        }
                        printf("\"");
                    }
                    printf(",\"crc32\":\"0x%08x\"", crc);
                }
#endif

                printf("}\r\n");
            } else {
                printf("Data Start Address: 0x%08x\r\n", tar0_start_address);
                printf("Data Length: %ub\r\n", tar0_len);
#ifdef ED25519_SUPPORT
                if (ed25519_secret) {
                    printf("SHA512: ");
                    for (c = 0; c < 64; c++) {
                        printf("%02x", (unsigned char)hash_buf[c]);
                    }
                    printf("\r\n");

                    printf("Signing PublicKey: ");
                    for (c = 0; c < 32; c++) {
                        printf("%02x", (unsigned char)public_key[c]);
                    }
                    printf("\r\n");

                    printf("Signature: ");
                    for (c = 0; c < 64; c++) {
                        printf("%02x", (unsigned char)signature[c]);
                    }
                    printf("\r\n");

                    if (ed25519_public_add) {
                        printf("Publisher PublicKey: ");
                        for (c = 0; c < 32; c++) {
                            printf("%02x", (unsigned char)public_key_publisher[c]);
                        }
                        printf("\r\n");
                    }
                    printf("CRC32 data: 0x%08x @0x%08x\r\n", crc, add_crc32 + tar0_start_address);
                }
#endif
                printf("Done.\r\n");
            }
        }
    } else {
        printf("error: processing input file\n");
    }

    return 0;
}

void print_help(void)
{
    printf("STM32 hex2dfu version 1.3\r\n");
    printf("(c) Encedo Ltd 2013-2015\r\n");
    printf("Options:\r\n");
    printf("-J        - output in JSON structure except errors (optional)\r\n");
    printf("-c        - place CRC23 under this addres (optional)\r\n");
    printf("-d        - file version number (optional, default: 0xFFFF)\r\n");
    printf("-h        - help\r\n");
    printf("-i        - Target0 HEX file name (mandatory)\r\n");
    printf("-l        - Target0 name (optional, default: EncedoKey)\r\n");
    printf("-o        - output DFU file name (mandatory)\r\n");
    printf("-S        - ED25519 'secret' to sign the code (optional)\r\n");
    printf("-P        - Publisher ED25519 'public' to verify firmware sign (optional)\r\n");
    printf("-e        - add Publisher ED25519 based on 'secret' or the one form -P (if given)\r\n");
    printf("-p        - USB Pid (optional, default: 0xDF11)\r\n");
    printf("-v        - USB Vid (optional, default: 0x0483)\r\n");
    printf("Example: hex2dfu -i infile.hex -i outfile.dfu\r\n");
}

int hex2bin(unsigned char* obuf, const char* ibuf, int len)
{
    unsigned char c, c2;

    len = len / 2;
    while (*ibuf != 0) {
        c = *ibuf++;
        if (c >= '0' && c <= '9')
            c -= '0';
        else if (c >= 'a' && c <= 'f')
            c -= 'a' - 10;
        else if (c >= 'A' && c <= 'F')
            c -= 'A' - 10;
        else
            return -1;

        c2 = *ibuf++;
        if (c2 >= '0' && c2 <= '9')
            c2 -= '0';
        else if (c2 >= 'a' && c2 <= 'f')
            c2 -= 'a' - 10;
        else if (c2 >= 'A' && c2 <= 'F')
            c2 -= 'A' - 10;
        else
            return -1;

        *obuf++ = (c << 4) | c2;
    }
    return len;
}

int check_checksum(unsigned char* inbuf, int len)
{
    unsigned int check = 0;
    while (len--) {
        check += *inbuf++;
    }
    return check & 0xFF;
}

// more details: http://en.wikipedia.org/wiki/Intel_HEX
unsigned char* ihex2bin_buf(unsigned int* start_address, int* dst_len, FILE* inFile)
{
    unsigned int lines = 0, total = 0, oneline_len, elar = 0, pos, cnt;
    unsigned char oneline[512], raw[256], start_set = 0, *dst = NULL;

    *dst_len = 1024 * 128;
    dst = malloc(*dst_len); //allocate 129kB of memory for bin data buffer
    if (dst == NULL) {
        *dst_len = -2;
        return NULL;
    }

    *start_address = 0;
    while (fgets(oneline, sizeof(oneline), inFile) != NULL) {
        if (oneline[0] == ':') { //is valid record?
            oneline_len = strlen(oneline) - 2; //get line length
            hex2bin(raw, oneline + 1, oneline_len); //convert to bin
            if (check_checksum(raw, oneline_len / 2) == 0) { //check cheksum validity
                if ((raw[0] == 2) && (raw[1] == 0) && (raw[2] == 0) && (raw[3] == 4)) { //> Extended Linear Address Record  :020000040803EF
                    elar = (unsigned int)raw[4] << 24 | (unsigned int)raw[5] << 16; //gen new address offset
                } else if ((raw[0] == 0) && (raw[1] == 0) && (raw[2] == 0) && (raw[3] == 1)) { //>End Of File record   :00000001FF
                    *dst_len = total; //return total size of bin data && start address
                    return dst;
                } else if (raw[3] == 0) { //>Data record - process
                    pos = elar + ((unsigned int)raw[1] << 8 | (unsigned int)raw[2]); //get start address of this chunk
                    if (start_set == 0) {
                        *start_address = pos; //set it as new start addres - only possible for first data record
                        start_set = 1; //only once - this is start address of thye binary data
                    }
                    pos -= *start_address;
                    cnt = raw[0]; //get chunk size/length
                    if (pos + cnt > *dst_len) { //enlarge buffer if required
                        unsigned char* dst_new = realloc(dst, *dst_len + 8192); //add 8kB of new space
                        if (dst_new == NULL) {
                            *dst_len = -2; //allocation error - exit
                            free(dst);
                            return NULL;
                        } else {
                            *dst_len += 8192;
                            dst = dst_new; //allocation succesed - copy new pointer
                        }
                    }
                    memmove(dst + pos, raw + 4, cnt);
                    if (pos + cnt > total) { //set new total variable
                        total = pos + cnt; //tricky way - file can be none linear!
                    }
                }
            } else {
                *dst_len = -1; //checksum error - exit
                return NULL;
            }
        }
        lines++; //not a IntelHex line - comment?
    }
    *dst_len = -3; //fatal error - no valid intel hex file processed
    free(dst);
    return NULL;
}

/*
//maybe usefull - stay here for future

int  ihex2bin(FILE * outFile, FILE *inFile) {
  unsigned int  total = 0, oneline_len, elar = 0, start = 0xFFFFFFFF, pos, cnt;
  unsigned char oneline [512], raw[256];
  
  while ( fgets (oneline , sizeof(oneline) , inFile) != NULL ) {
   //puts (oneline);
   if (oneline[0] == ':') {
      oneline_len = strlen(oneline)-2;
      hex2bin(raw, oneline+1, oneline_len);
      if (check_checksum(raw, oneline_len/2) == 0) {
        if ((raw[0] == 2) && (raw[1] == 0) && (raw[2] == 0) && (raw[3] == 4)) {  //:020000040803EF
          elar = (unsigned int)raw[4]<<24 | (unsigned int) raw[5]<<16;
          if (start == 0xFFFFFFFF) {
            start = elar;          
          }
        } else
        if ((raw[0] == 0) && (raw[1] == 0) && (raw[2] == 0) && (raw[3] == 1)) {  //:00000001FF
          return start;
        } else
        if (raw[3] == 0) {  //data
          pos = elar + ( (unsigned int)raw[1]<<8 | (unsigned int)raw[2] );
          cnt = raw[0];
          fseek ( outFile, pos-start, SEEK_SET );
          fwrite (raw+4 , sizeof(unsigned char), cnt, outFile);
          if (pos+cnt > total)
            total = pos+cnt;
        }
      } else {
        return -1;
      }
   }
  }
  return total;
}
*/

const unsigned int crc32_tab[] = {
    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
    0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
    0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
    0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
    0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
    0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
    0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
    0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
    0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
    0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
    0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
    0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
    0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
    0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
    0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
    0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
    0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
    0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
    0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
    0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
    0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
    0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
    0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
    0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
    0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
    0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
    0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
    0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
    0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
    0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
    0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
    0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
    0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
    0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
    0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
    0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
    0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
    0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
    0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
    0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
};

unsigned int crc32(unsigned int crc, const void* buf, size_t size)
{
    const unsigned char* p;

    p = buf;
    crc = crc ^ ~0U;

    while (size--)
        crc = crc32_tab[(crc ^ *p++) & 0xFF] ^ (crc >> 8);

    return crc ^ ~0U;
}