Logo Search packages:      
Sourcecode: jpeginfo version File versions  Download package

md5.c

/*
 * This code implements the MD5 message-digest algorithm.
 * The algorithm is due to Ron Rivest.  This code was
 * written by Colin Plumb in 1993, no copyright is claimed.
 * This code is in the public domain; do with it what you wish.
 *
 * Equivalent code is available from RSA Data Security, Inc.
 * This code has been tested against that, and is equivalent,
 * except that you don't need to include two pages of legalese
 * with every copy.
 *
 * To compute the message digest of a chunk of bytes, declare an
 * MD5Context structure, pass it to MD5Init, call MD5Update as
 * needed on buffers full of bytes, and then call MD5Final, which
 * will fill a supplied 16-byte array with the digest.
 */

#include "config.h"

#if HAVE_STRING_H || STDC_HEADERS
#include <string.h>     /* for memcpy() */
#endif

/* Add prototype support.  */
#ifndef PROTO
#if defined (USE_PROTOTYPES) ? USE_PROTOTYPES : defined (__STDC__)
#define PROTO(ARGS) ARGS
#else
#define PROTO(ARGS) ()
#endif
#endif

#include "md5.h"

void byteReverse PROTO ((unsigned char *buf, unsigned longs));

#ifndef ASM_MD5
/*
 * Note: this code is harmless on little-endian machines.
 */
void byteReverse (buf, longs)
     unsigned char *buf;
     unsigned longs;
{
      uint32 t;
      do {
            t = (uint32)((unsigned)buf[3]<<8 | buf[2]) << 16 |
                        ((unsigned)buf[1]<<8 | buf[0]);
            *(uint32 *)buf = t;
            buf += 4;
      } while (--longs);
}
#endif

/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
void
MD5Init(ctx)
     struct MD5Context *ctx;
{
      ctx->buf[0] = 0x67452301;
      ctx->buf[1] = 0xefcdab89;
      ctx->buf[2] = 0x98badcfe;
      ctx->buf[3] = 0x10325476;

      ctx->bits[0] = 0;
      ctx->bits[1] = 0;
}

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
void
MD5Update(ctx, buf, len)
     struct MD5Context *ctx;
     unsigned char const *buf;
     unsigned len;
{
      uint32 t;

      /* Update bitcount */

      t = ctx->bits[0];
      if ((ctx->bits[0] = t + ((uint32)len << 3)) < t)
            ctx->bits[1]++;   /* Carry from low to high */
      ctx->bits[1] += len >> 29;

      t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */

      /* Handle any leading odd-sized chunks */

      if ( t ) {
            unsigned char *p = (unsigned char *)ctx->in + t;

            t = 64-t;
            if (len < t) {
                  memcpy(p, buf, len);
                  return;
            }
            memcpy(p, buf, t);
            byteReverse(ctx->in, 16);
            MD5Transform(ctx->buf, (uint32 *)ctx->in);
            buf += t;
            len -= t;
      }

      /* Process data in 64-byte chunks */

      while (len >= 64) {
            memcpy(ctx->in, buf, 64);
            byteReverse(ctx->in, 16);
            MD5Transform(ctx->buf, (uint32 *)ctx->in);
            buf += 64;
            len -= 64;
      }

      /* Handle any remaining bytes of data. */

      memcpy(ctx->in, buf, len);
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern 
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
void
MD5Final(digest, ctx)
     unsigned char digest[16];
     struct MD5Context *ctx;
{
      unsigned count;
      unsigned char *p;

      /* Compute number of bytes mod 64 */
      count = (ctx->bits[0] >> 3) & 0x3F;

      /* Set the first char of padding to 0x80.  This is safe since there is
         always at least one byte free */
      p = ctx->in + count;
      *p++ = 0x80;

      /* Bytes of padding needed to make 64 bytes */
      count = 64 - 1 - count;

      /* Pad out to 56 mod 64 */
      if (count < 8) {
            /* Two lots of padding:  Pad the first block to 64 bytes */
            memset(p, 0, count);
            byteReverse(ctx->in, 16);
            MD5Transform(ctx->buf, (uint32 *)ctx->in);

            /* Now fill the next block with 56 bytes */
            memset(ctx->in, 0, 56);
      } else {
            /* Pad block to 56 bytes */
            memset(p, 0, count-8);
      }
      byteReverse(ctx->in, 14);

      /* Append length in bits and transform */
      ((uint32 *)ctx->in)[ 14 ] = ctx->bits[0];
      ((uint32 *)ctx->in)[ 15 ] = ctx->bits[1];

      MD5Transform(ctx->buf, (uint32 *)ctx->in);
      byteReverse((unsigned char *)ctx->buf, 4);
      memcpy(digest, ctx->buf, 16);
      memset(ctx, 0, sizeof(ctx));  /* In case it's sensitive */
}

#ifndef ASM_MD5

/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
      ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
void
MD5Transform(buf, in)
     uint32 buf[4];
     uint32 const in[16];
{
      register uint32 a, b, c, d;

      a = buf[0];
      b = buf[1];
      c = buf[2];
      d = buf[3];

      MD5STEP(F1, a, b, c, d, in[ 0]+0xd76aa478,  7);
      MD5STEP(F1, d, a, b, c, in[ 1]+0xe8c7b756, 12);
      MD5STEP(F1, c, d, a, b, in[ 2]+0x242070db, 17);
      MD5STEP(F1, b, c, d, a, in[ 3]+0xc1bdceee, 22);
      MD5STEP(F1, a, b, c, d, in[ 4]+0xf57c0faf,  7);
      MD5STEP(F1, d, a, b, c, in[ 5]+0x4787c62a, 12);
      MD5STEP(F1, c, d, a, b, in[ 6]+0xa8304613, 17);
      MD5STEP(F1, b, c, d, a, in[ 7]+0xfd469501, 22);
      MD5STEP(F1, a, b, c, d, in[ 8]+0x698098d8,  7);
      MD5STEP(F1, d, a, b, c, in[ 9]+0x8b44f7af, 12);
      MD5STEP(F1, c, d, a, b, in[10]+0xffff5bb1, 17);
      MD5STEP(F1, b, c, d, a, in[11]+0x895cd7be, 22);
      MD5STEP(F1, a, b, c, d, in[12]+0x6b901122,  7);
      MD5STEP(F1, d, a, b, c, in[13]+0xfd987193, 12);
      MD5STEP(F1, c, d, a, b, in[14]+0xa679438e, 17);
      MD5STEP(F1, b, c, d, a, in[15]+0x49b40821, 22);

      MD5STEP(F2, a, b, c, d, in[ 1]+0xf61e2562,  5);
      MD5STEP(F2, d, a, b, c, in[ 6]+0xc040b340,  9);
      MD5STEP(F2, c, d, a, b, in[11]+0x265e5a51, 14);
      MD5STEP(F2, b, c, d, a, in[ 0]+0xe9b6c7aa, 20);
      MD5STEP(F2, a, b, c, d, in[ 5]+0xd62f105d,  5);
      MD5STEP(F2, d, a, b, c, in[10]+0x02441453,  9);
      MD5STEP(F2, c, d, a, b, in[15]+0xd8a1e681, 14);
      MD5STEP(F2, b, c, d, a, in[ 4]+0xe7d3fbc8, 20);
      MD5STEP(F2, a, b, c, d, in[ 9]+0x21e1cde6,  5);
      MD5STEP(F2, d, a, b, c, in[14]+0xc33707d6,  9);
      MD5STEP(F2, c, d, a, b, in[ 3]+0xf4d50d87, 14);
      MD5STEP(F2, b, c, d, a, in[ 8]+0x455a14ed, 20);
      MD5STEP(F2, a, b, c, d, in[13]+0xa9e3e905,  5);
      MD5STEP(F2, d, a, b, c, in[ 2]+0xfcefa3f8,  9);
      MD5STEP(F2, c, d, a, b, in[ 7]+0x676f02d9, 14);
      MD5STEP(F2, b, c, d, a, in[12]+0x8d2a4c8a, 20);

      MD5STEP(F3, a, b, c, d, in[ 5]+0xfffa3942,  4);
      MD5STEP(F3, d, a, b, c, in[ 8]+0x8771f681, 11);
      MD5STEP(F3, c, d, a, b, in[11]+0x6d9d6122, 16);
      MD5STEP(F3, b, c, d, a, in[14]+0xfde5380c, 23);
      MD5STEP(F3, a, b, c, d, in[ 1]+0xa4beea44,  4);
      MD5STEP(F3, d, a, b, c, in[ 4]+0x4bdecfa9, 11);
      MD5STEP(F3, c, d, a, b, in[ 7]+0xf6bb4b60, 16);
      MD5STEP(F3, b, c, d, a, in[10]+0xbebfbc70, 23);
      MD5STEP(F3, a, b, c, d, in[13]+0x289b7ec6,  4);
      MD5STEP(F3, d, a, b, c, in[ 0]+0xeaa127fa, 11);
      MD5STEP(F3, c, d, a, b, in[ 3]+0xd4ef3085, 16);
      MD5STEP(F3, b, c, d, a, in[ 6]+0x04881d05, 23);
      MD5STEP(F3, a, b, c, d, in[ 9]+0xd9d4d039,  4);
      MD5STEP(F3, d, a, b, c, in[12]+0xe6db99e5, 11);
      MD5STEP(F3, c, d, a, b, in[15]+0x1fa27cf8, 16);
      MD5STEP(F3, b, c, d, a, in[ 2]+0xc4ac5665, 23);

      MD5STEP(F4, a, b, c, d, in[ 0]+0xf4292244,  6);
      MD5STEP(F4, d, a, b, c, in[ 7]+0x432aff97, 10);
      MD5STEP(F4, c, d, a, b, in[14]+0xab9423a7, 15);
      MD5STEP(F4, b, c, d, a, in[ 5]+0xfc93a039, 21);
      MD5STEP(F4, a, b, c, d, in[12]+0x655b59c3,  6);
      MD5STEP(F4, d, a, b, c, in[ 3]+0x8f0ccc92, 10);
      MD5STEP(F4, c, d, a, b, in[10]+0xffeff47d, 15);
      MD5STEP(F4, b, c, d, a, in[ 1]+0x85845dd1, 21);
      MD5STEP(F4, a, b, c, d, in[ 8]+0x6fa87e4f,  6);
      MD5STEP(F4, d, a, b, c, in[15]+0xfe2ce6e0, 10);
      MD5STEP(F4, c, d, a, b, in[ 6]+0xa3014314, 15);
      MD5STEP(F4, b, c, d, a, in[13]+0x4e0811a1, 21);
      MD5STEP(F4, a, b, c, d, in[ 4]+0xf7537e82,  6);
      MD5STEP(F4, d, a, b, c, in[11]+0xbd3af235, 10);
      MD5STEP(F4, c, d, a, b, in[ 2]+0x2ad7d2bb, 15);
      MD5STEP(F4, b, c, d, a, in[ 9]+0xeb86d391, 21);

      buf[0] += a;
      buf[1] += b;
      buf[2] += c;
      buf[3] += d;
}
#endif

Generated by  Doxygen 1.6.0   Back to index