Нужна реализация кода md5

#include "md5.h"
#include "string.h"
 
#ifdef TEST
/*
 * Compile with -DTEST to create a self-contained executable test program.
 * The test program should print out the same values as given in section
 * A.5 of RFC 1321, reproduced below.
 */
main()
{
    static const char *const test[7] = {
    "", /*d41d8cd98f00b204e9800998ecf8427e*/
    "a", /*0cc175b9c0f1b6a831c399e269772661*/
    "abc", /*900150983cd24fb0d6963f7d28e17f72*/
    "message digest", /*f96b697d7cb7938d525a2f31aaf161d0*/
    "abcdefghijklmnopqrstuvwxyz", /*c3fcd3d76192e4007dfb496cca67e13b*/
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
                /*d174ab98d277d9f5a5611c2c9f419d9f*/
    "12345678901234567890123456789012345678901234567890123456789012345678901234567890" /*57edf4a22be3c955ac49da2e2107b67a*/
    };
    int i;
 
    for (i = 0; i < 7; ++i) {
    md5_state_t state;
    md5_byte_t digest[16];
    int di;
 
    md5_init(&state);
    md5_append(&state, (const md5_byte_t *)test[i], strlen(test[i]));
    md5_finish(&state, digest);
    printf("MD5 (\"%s\") = ", test[i]);
    for (di = 0; di < 16; ++di)
        printf("%02x", digest[di]);
    printf("\n");
    }
    return 0;
}
#endif /* TEST */
 
 
/*
 * For reference, here is the program that computed the T values.
 */
#if 0
#include <math.h>
main()
{
    int i;
    for (i = 1; i <= 64; ++i) {
    unsigned long v = (unsigned long)(4294967296.0 * fabs(sin((double)i)));
    printf("#define T%d 0x%08lx\n", i, v);
    }
    return 0;
}
#endif
/*
 * End of T computation program.
 */
#define T1 0xd76aa478
#define T2 0xe8c7b756
#define T3 0x242070db
#define T4 0xc1bdceee
#define T5 0xf57c0faf
#define T6 0x4787c62a
#define T7 0xa8304613
#define T8 0xfd469501
#define T9 0x698098d8
#define T10 0x8b44f7af
#define T11 0xffff5bb1
#define T12 0x895cd7be
#define T13 0x6b901122
#define T14 0xfd987193
#define T15 0xa679438e
#define T16 0x49b40821
#define T17 0xf61e2562
#define T18 0xc040b340
#define T19 0x265e5a51
#define T20 0xe9b6c7aa
#define T21 0xd62f105d
#define T22 0x02441453
#define T23 0xd8a1e681
#define T24 0xe7d3fbc8
#define T25 0x21e1cde6
#define T26 0xc33707d6
#define T27 0xf4d50d87
#define T28 0x455a14ed
#define T29 0xa9e3e905
#define T30 0xfcefa3f8
#define T31 0x676f02d9
#define T32 0x8d2a4c8a
#define T33 0xfffa3942
#define T34 0x8771f681
#define T35 0x6d9d6122
#define T36 0xfde5380c
#define T37 0xa4beea44
#define T38 0x4bdecfa9
#define T39 0xf6bb4b60
#define T40 0xbebfbc70
#define T41 0x289b7ec6
#define T42 0xeaa127fa
#define T43 0xd4ef3085
#define T44 0x04881d05
#define T45 0xd9d4d039
#define T46 0xe6db99e5
#define T47 0x1fa27cf8
#define T48 0xc4ac5665
#define T49 0xf4292244
#define T50 0x432aff97
#define T51 0xab9423a7
#define T52 0xfc93a039
#define T53 0x655b59c3
#define T54 0x8f0ccc92
#define T55 0xffeff47d
#define T56 0x85845dd1
#define T57 0x6fa87e4f
#define T58 0xfe2ce6e0
#define T59 0xa3014314
#define T60 0x4e0811a1
#define T61 0xf7537e82
#define T62 0xbd3af235
#define T63 0x2ad7d2bb
#define T64 0xeb86d391
 
static void
md5_process(md5_state_t *pms, const md5_byte_t *data /*[64]*/)
{
    md5_word_t
    a = pms->abcd[0], b = pms->abcd[1],
    c = pms->abcd[2], d = pms->abcd[3];
    md5_word_t t;
 
#ifndef ARCH_IS_BIG_ENDIAN
# define ARCH_IS_BIG_ENDIAN 1   /* slower, default implementation */
#endif
#if ARCH_IS_BIG_ENDIAN
 
    /*
     * On big-endian machines, we must arrange the bytes in the right
     * order.  (This also works on machines of unknown byte order.)
     */
    md5_word_t X[16];
    const md5_byte_t *xp = data;
    int i;
 
    for (i = 0; i < 16; ++i, xp += 4)
    X[i] = xp[0] + (xp[1] << 8) + (xp[2] << 16) + (xp[3] << 24);
 
#else  /* !ARCH_IS_BIG_ENDIAN */
 
    /*
     * On little-endian machines, we can process properly aligned data
     * without copying it.
     */
    md5_word_t xbuf[16];
    const md5_word_t *X;
 
    if (!((data - (const md5_byte_t *)0) & 3)) {
    /* data are properly aligned */
    X = (const md5_word_t *)data;
    } else {
    /* not aligned */
    memcpy(xbuf, data, 64);
    X = xbuf;
    }
#endif
 
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))
 
    /* Round 1. */
    /* Let [abcd k s i] denote the operation
       a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */
#define F(x, y, z) (((x) & (y)) | (~(x) & (z)))
#define SET(a, b, c, d, k, s, Ti)\
  t = a + F(b,c,d) + X[k] + Ti;\
  a = ROTATE_LEFT(t, s) + b
    /* Do the following 16 operations. */
    SET(a, b, c, d,  0,  7,  T1);
    SET(d, a, b, c,  1, 12,  T2);
    SET(c, d, a, b,  2, 17,  T3);
    SET(b, c, d, a,  3, 22,  T4);
    SET(a, b, c, d,  4,  7,  T5);
    SET(d, a, b, c,  5, 12,  T6);
    SET(c, d, a, b,  6, 17,  T7);
    SET(b, c, d, a,  7, 22,  T8);
    SET(a, b, c, d,  8,  7,  T9);
    SET(d, a, b, c,  9, 12, T10);
    SET(c, d, a, b, 10, 17, T11);
    SET(b, c, d, a, 11, 22, T12);
    SET(a, b, c, d, 12,  7, T13);
    SET(d, a, b, c, 13, 12, T14);
    SET(c, d, a, b, 14, 17, T15);
    SET(b, c, d, a, 15, 22, T16);
#undef SET
 
     /* Round 2. */
     /* Let [abcd k s i] denote the operation
          a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */
#define G(x, y, z) (((x) & (z)) | ((y) & ~(z)))
#define SET(a, b, c, d, k, s, Ti)\
  t = a + G(b,c,d) + X[k] + Ti;\
  a = ROTATE_LEFT(t, s) + b
     /* Do the following 16 operations. */
    SET(a, b, c, d,  1,  5, T17);
    SET(d, a, b, c,  6,  9, T18);
    SET(c, d, a, b, 11, 14, T19);
    SET(b, c, d, a,  0, 20, T20);
    SET(a, b, c, d,  5,  5, T21);
    SET(d, a, b, c, 10,  9, T22);
    SET(c, d, a, b, 15, 14, T23);
    SET(b, c, d, a,  4, 20, T24);
    SET(a, b, c, d,  9,  5, T25);
    SET(d, a, b, c, 14,  9, T26);
    SET(c, d, a, b,  3, 14, T27);
    SET(b, c, d, a,  8, 20, T28);
    SET(a, b, c, d, 13,  5, T29);
    SET(d, a, b, c,  2,  9, T30);
    SET(c, d, a, b,  7, 14, T31);
    SET(b, c, d, a, 12, 20, T32);
#undef SET
 
     /* Round 3. */
     /* Let [abcd k s t] denote the operation
          a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define SET(a, b, c, d, k, s, Ti)\
  t = a + H(b,c,d) + X[k] + Ti;\
  a = ROTATE_LEFT(t, s) + b
     /* Do the following 16 operations. */
    SET(a, b, c, d,  5,  4, T33);
    SET(d, a, b, c,  8, 11, T34);
    SET(c, d, a, b, 11, 16, T35);
    SET(b, c, d, a, 14, 23, T36);
    SET(a, b, c, d,  1,  4, T37);
    SET(d, a, b, c,  4, 11, T38);
    SET(c, d, a, b,  7, 16, T39);
    SET(b, c, d, a, 10, 23, T40);
    SET(a, b, c, d, 13,  4, T41);
    SET(d, a, b, c,  0, 11, T42);
    SET(c, d, a, b,  3, 16, T43);
    SET(b, c, d, a,  6, 23, T44);
    SET(a, b, c, d,  9,  4, T45);
    SET(d, a, b, c, 12, 11, T46);
    SET(c, d, a, b, 15, 16, T47);
    SET(b, c, d, a,  2, 23, T48);
#undef SET
 
     /* Round 4. */
     /* Let [abcd k s t] denote the operation
          a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */
#define I(x, y, z) ((y) ^ ((x) | ~(z)))
#define SET(a, b, c, d, k, s, Ti)\
  t = a + I(b,c,d) + X[k] + Ti;\
  a = ROTATE_LEFT(t, s) + b
     /* Do the following 16 operations. */
    SET(a, b, c, d,  0,  6, T49);
    SET(d, a, b, c,  7, 10, T50);
    SET(c, d, a, b, 14, 15, T51);
    SET(b, c, d, a,  5, 21, T52);
    SET(a, b, c, d, 12,  6, T53);
    SET(d, a, b, c,  3, 10, T54);
    SET(c, d, a, b, 10, 15, T55);
    SET(b, c, d, a,  1, 21, T56);
    SET(a, b, c, d,  8,  6, T57);
    SET(d, a, b, c, 15, 10, T58);
    SET(c, d, a, b,  6, 15, T59);
    SET(b, c, d, a, 13, 21, T60);
    SET(a, b, c, d,  4,  6, T61);
    SET(d, a, b, c, 11, 10, T62);
    SET(c, d, a, b,  2, 15, T63);
    SET(b, c, d, a,  9, 21, T64);
#undef SET
 
     /* Then perform the following additions. (That is increment each
        of the four registers by the value it had before this block
        was started.) */
    pms->abcd[0] += a;
    pms->abcd[1] += b;
    pms->abcd[2] += c;
    pms->abcd[3] += d;
}
 
void
md5_init(md5_state_t *pms)
{
    pms->count[0] = pms->count[1] = 0;
    pms->abcd[0] = 0x67452301;
    pms->abcd[1] = 0xefcdab89;
    pms->abcd[2] = 0x98badcfe;
    pms->abcd[3] = 0x10325476;
}
 
void
md5_append(md5_state_t *pms, const md5_byte_t *data, int nbytes)
{
    const md5_byte_t *p = data;
    int left = nbytes;
    int offset = (pms->count[0] >> 3) & 63;
    md5_word_t nbits = (md5_word_t)(nbytes << 3);
 
    if (nbytes <= 0)
    return;
 
    /* Update the message length. */
    pms->count[1] += nbytes >> 29;
    pms->count[0] += nbits;
    if (pms->count[0] < nbits)
    pms->count[1]++;
 
    /* Process an initial partial block. */
    if (offset) {
    int copy = (offset + nbytes > 64 ? 64 - offset : nbytes);
 
    memcpy(pms->buf + offset, p, copy);
    if (offset + copy < 64)
        return;
    p += copy;
    left -= copy;
    md5_process(pms, pms->buf);
    }
 
    /* Process full blocks. */
    for (; left >= 64; p += 64, left -= 64)
    md5_process(pms, p);
 
    /* Process a final partial block. */
    if (left)
    memcpy(pms->buf, p, left);
}
 
void
md5_finish(md5_state_t *pms, md5_byte_t digest[16])
{
    static const md5_byte_t pad[64] = {
    0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
    };
    md5_byte_t data[8];
    int i;
 
    /* Save the length before padding. */
    for (i = 0; i < 8; ++i)
    data[i] = (md5_byte_t)(pms->count[i >> 2] >> ((i & 3) << 3));
    /* Pad to 56 bytes mod 64. */
    md5_append(pms, pad, ((55 - (pms->count[0] >> 3)) & 63) + 1);
    /* Append the length. */
    md5_append(pms, data, 8);
    for (i = 0; i < 16; ++i)
    digest[i] = (md5_byte_t)(pms->abcd[i >> 2] >> ((i & 3) << 3));
}