md5/md5.c

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <sys/types.h>

#if STDC_HEADERS || defined _LIBC
# include <stdlib.h>
# include <string.h>
#else
# ifndef HAVE_MEMCPY
#  define memcpy(d, s, n) bcopy ((s), (d), (n))
# endif
#endif

#include "md5.h"

#ifdef _LIBC
# include <endian.h>
# if __BYTE_ORDER == __BIG_ENDIAN
#  define WORDS_BIGENDIAN 1
# endif
#endif

#ifdef WORDS_BIGENDIAN
# define SWAP(n)                            \
    (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
#else
# define SWAP(n) (n)
#endif


static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ...  */ };


/* Initialize structure containing state of computation.
   (RFC 1321, 3.3: Step 3)  */
void
md5_init_ctx (ctx)
     struct md5_ctx *ctx;
{
  ctx->A = 0x67452301;
  ctx->B = 0xefcdab89;
  ctx->C = 0x98badcfe;
  ctx->D = 0x10325476;

  ctx->total[0] = ctx->total[1] = 0;
  ctx->buflen = 0;
}


void *
md5_read_ctx (ctx, resbuf)
     const struct md5_ctx *ctx;
     void *resbuf;
{
  ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
  ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
  ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
  ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);

  return resbuf;
}


  md5_uint32 bytes = ctx->buflen;
  size_t pad;

  /* Now count remaining bytes.  */
  ctx->total[0] += bytes;
  if (ctx->total[0] < bytes)
    ++ctx->total[1];

  pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
  memcpy (&ctx->buffer[bytes], fillbuf, pad);

  /* Put the 64-bit file length in *bits* at the end of the buffer.  */
  *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
  *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) |
                            (ctx->total[0] >> 29));

  /* Process last bytes.  */
  md5_process_block (ctx->buffer, bytes + pad + 8, ctx);

  return md5_read_ctx (ctx, resbuf);
}


int
md5_stream (stream, resblock)
     FILE *stream;
     void *resblock;
{
  /* Important: BLOCKSIZE must be a multiple of 64.  */
#define BLOCKSIZE 4096
  struct md5_ctx ctx;
  char buffer[BLOCKSIZE + 72];
  size_t sum;

  /* Initialize the computation context.  */
  md5_init_ctx (&ctx);

  /* Iterate over full file contents.  */
  while (1)
    {

      size_t n;
      sum = 0;

      /* Read block.  Take care for partial reads.  */
      do
    {
      n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);

      sum += n;
    }
      while (sum < BLOCKSIZE && n != 0);
      if (n == 0 && ferror (stream))
        return 1;

      /* If end of file is reached, end the loop.  */
      if (n == 0)
    break;

      /* Process buffer with BLOCKSIZE bytes.  Note that
            BLOCKSIZE % 64 == 0
       */
      md5_process_block (buffer, BLOCKSIZE, &ctx);
    }

  /* Add the last bytes if necessary.  */
  if (sum > 0)
    md5_process_bytes (buffer, sum, &ctx);

  /* Construct result in desired memory.  */
  md5_finish_ctx (&ctx, resblock);
  return 0;
}


void *
md5_buffer (buffer, len, resblock)
     const char *buffer;
     size_t len;
     void *resblock;
{
  struct md5_ctx ctx;

  /* Initialize the computation context.  */
  md5_init_ctx (&ctx);


  md5_process_bytes (buffer, len, &ctx);

  /* Put result in desired memory area.  */
  return md5_finish_ctx (&ctx, resblock);
}


void
md5_process_bytes (buffer, len, ctx)
     const void *buffer;
     size_t len;
     struct md5_ctx *ctx;
{

  if (ctx->buflen != 0)
    {
      size_t left_over = ctx->buflen;
      size_t add = 128 - left_over > len ? len : 128 - left_over;

      memcpy (&ctx->buffer[left_over], buffer, add);
      ctx->buflen += add;

      if (left_over + add > 64)
    {
      md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx);
      memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
          (left_over + add) & 63);
      ctx->buflen = (left_over + add) & 63;
    }

      buffer = (const char *) buffer + add;
      len -= add;
    }

  /* Process available complete blocks.  */
  if (len > 64)
    {
      md5_process_block (buffer, len & ~63, ctx);
      buffer = (const char *) buffer + (len & ~63);
      len &= 63;
    }

  /* Move remaining bytes in internal buffer.  */
  if (len > 0)
    {
      memcpy (ctx->buffer, buffer, len);
      ctx->buflen = len;
    }
}



#define FF(b, c, d) (d ^ (b & (c ^ d)))
#define FG(b, c, d) FF (d, b, c)
#define FH(b, c, d) (b ^ c ^ d)
#define FI(b, c, d) (c ^ (b | ~d))


void
md5_process_block (buffer, len, ctx)
     const void *buffer;
     size_t len;
     struct md5_ctx *ctx;
{
  md5_uint32 correct_words[16];
  const md5_uint32 *words = buffer;
  size_t nwords = len / sizeof (md5_uint32);
  const md5_uint32 *endp = words + nwords;
  md5_uint32 A = ctx->A;
  md5_uint32 B = ctx->B;
  md5_uint32 C = ctx->C;
  md5_uint32 D = ctx->D;


  ctx->total[0] += len;
  if (ctx->total[0] < len)
    ++ctx->total[1];

  /* Process all bytes in the buffer with 64 bytes in each round of
     the loop.  */
  while (words < endp)
    {
      md5_uint32 *cwp = correct_words;
      md5_uint32 A_save = A;
      md5_uint32 B_save = B;
      md5_uint32 C_save = C;
      md5_uint32 D_save = D;



#define OP(a, b, c, d, s, T)                        \
      do                                \
        {                               \
      a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T;     \
      ++words;                          \
      CYCLIC (a, s);                        \
      a += b;                           \
        }                               \
      while (0)


#define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))

      /* Before we start, one word to the strange constants.
     They are defined in RFC 1321 as

     T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
       */

      /* Round 1.  */
      OP (A, B, C, D,  7, 0xd76aa478);
      OP (D, A, B, C, 12, 0xe8c7b756);
      OP (C, D, A, B, 17, 0x242070db);
      OP (B, C, D, A, 22, 0xc1bdceee);
      OP (A, B, C, D,  7, 0xf57c0faf);
      OP (D, A, B, C, 12, 0x4787c62a);
      OP (C, D, A, B, 17, 0xa8304613);
      OP (B, C, D, A, 22, 0xfd469501);
      OP (A, B, C, D,  7, 0x698098d8);
      OP (D, A, B, C, 12, 0x8b44f7af);
      OP (C, D, A, B, 17, 0xffff5bb1);
      OP (B, C, D, A, 22, 0x895cd7be);
      OP (A, B, C, D,  7, 0x6b901122);
      OP (D, A, B, C, 12, 0xfd987193);
      OP (C, D, A, B, 17, 0xa679438e);
      OP (B, C, D, A, 22, 0x49b40821);


#undef OP
#define OP(f, a, b, c, d, k, s, T)                  \
      do                                \
    {                               \
      a += f (b, c, d) + correct_words[k] + T;          \
      CYCLIC (a, s);                        \
      a += b;                           \
    }                               \
      while (0)

      /* Round 2.  */
      OP (FG, A, B, C, D,  1,  5, 0xf61e2562);
      OP (FG, D, A, B, C,  6,  9, 0xc040b340);
      OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
      OP (FG, B, C, D, A,  0, 20, 0xe9b6c7aa);
      OP (FG, A, B, C, D,  5,  5, 0xd62f105d);
      OP (FG, D, A, B, C, 10,  9, 0x02441453);
      OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
      OP (FG, B, C, D, A,  4, 20, 0xe7d3fbc8);
      OP (FG, A, B, C, D,  9,  5, 0x21e1cde6);
      OP (FG, D, A, B, C, 14,  9, 0xc33707d6);
      OP (FG, C, D, A, B,  3, 14, 0xf4d50d87);
      OP (FG, B, C, D, A,  8, 20, 0x455a14ed);
      OP (FG, A, B, C, D, 13,  5, 0xa9e3e905);
      OP (FG, D, A, B, C,  2,  9, 0xfcefa3f8);
      OP (FG, C, D, A, B,  7, 14, 0x676f02d9);
      OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);

      /* Round 3.  */
      OP (FH, A, B, C, D,  5,  4, 0xfffa3942);
      OP (FH, D, A, B, C,  8, 11, 0x8771f681);
      OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
      OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
      OP (FH, A, B, C, D,  1,  4, 0xa4beea44);
      OP (FH, D, A, B, C,  4, 11, 0x4bdecfa9);
      OP (FH, C, D, A, B,  7, 16, 0xf6bb4b60);
      OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
      OP (FH, A, B, C, D, 13,  4, 0x289b7ec6);
      OP (FH, D, A, B, C,  0, 11, 0xeaa127fa);
      OP (FH, C, D, A, B,  3, 16, 0xd4ef3085);
      OP (FH, B, C, D, A,  6, 23, 0x04881d05);
      OP (FH, A, B, C, D,  9,  4, 0xd9d4d039);
      OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
      OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
      OP (FH, B, C, D, A,  2, 23, 0xc4ac5665);

      /* Round 4.  */
      OP (FI, A, B, C, D,  0,  6, 0xf4292244);
      OP (FI, D, A, B, C,  7, 10, 0x432aff97);
      OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
      OP (FI, B, C, D, A,  5, 21, 0xfc93a039);
      OP (FI, A, B, C, D, 12,  6, 0x655b59c3);
      OP (FI, D, A, B, C,  3, 10, 0x8f0ccc92);
      OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
      OP (FI, B, C, D, A,  1, 21, 0x85845dd1);
      OP (FI, A, B, C, D,  8,  6, 0x6fa87e4f);
      OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
      OP (FI, C, D, A, B,  6, 15, 0xa3014314);
      OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
      OP (FI, A, B, C, D,  4,  6, 0xf7537e82);
      OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
      OP (FI, C, D, A, B,  2, 15, 0x2ad7d2bb);
      OP (FI, B, C, D, A,  9, 21, 0xeb86d391);

      /* Add the starting values of the context.  */
      A += A_save;
      B += B_save;
      C += C_save;
      D += D_save;
    }

  /* Put checksum in context given as argument.  */
  ctx->A = A;
  ctx->B = B;
  ctx->C = C;
  ctx->D = D;
}