text: /*
   * 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.
   */
  
  /* Brutally hacked by John Walker back from ANSI C to K&R (no
     prototypes) to maintain the tradition that Netfone will compile
     with Sun's original "cc". */
  
  #include <memory.h>      /* for memcpy() */
  #include "md5.h"
  
  #ifndef HIGHFIRST
  #define byteReverse(buf, len)   /* Nothing */
  #else
  /*
   * Note: this code is harmless on little-endian machines.
   */
  static void byteReverse(buf, longs)
      unsigned char *buf; unsigned longs;
  {
      uint32_t t;
      do {
          t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
              ((unsigned) buf[1] << 8 | buf[0]);
          *(uint32_t *) 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 t;
  
      /* Update bitcount */
  
      t = ctx->bits[0];
      if ((ctx->bits[0] = t + ((uint32_t) 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_t *) 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_t *) 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_t *) 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_t *) ctx->in)[14] = ctx->bits[0];
      ((uint32_t *) ctx->in)[15] = ctx->bits[1];
  
      MD5Transform(ctx->buf, (uint32_t *) ctx->in);
      byteReverse((unsigned char *) ctx->buf, 4);
      memcpy(digest, ctx->buf, 16);
      memset(ctx, 0, sizeof(ctx));        /* In case it's sensitive */
  }
  
  
  /* 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_t buf[4]; uint32_t in[16];
  {
      register uint32_t 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;
  }
  /* vim:set et sw=4 ts=4: */
  