/*
 * $Id: md5.c,v 1.1.1.1 2009-06-24 14:37:29 jdutheil Exp $
 *
 * 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 MD5_Init, call MD5_Update as
 * needed on buffers full of bytes, and then call MD5_Final, which
 * will fill a supplied 16-byte array with the digest.
 *
 * Modified 12 June 2003 Jeremy Katz <katzj@redhat.com> to handle
 *    endianness better
 *
 */
// taken from DEBIAN package isomd5sum
#include <string.h>
#include <stdio.h>
#ifdef WIN32
#define IS_BIG_ENDIAN 0
#else
#include <sys/types.h>
#if !(defined(_BIG_ENDIAN) || defined(BIG_ENDIAN))
#define IS_BIG_ENDIAN 0
#else
#define IS_BIG_ENDIAN 1
#endif
#endif


typedef unsigned int uint32;

struct MD5Context
{
  uint32 buf[4];
  uint32 bits[2];
  unsigned char in[64];
  int doByteReverse;
};

static void MD5_Transform(uint32* buf, uint32 const* in);

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

#ifndef ASM_MD5
/*
 * Note: this code is harmless on little-endian machines.
 */
static void byteReverse(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.
 */
static void MD5_Init(struct MD5Context* ctx)
{
  ctx->buf[0] = 0x67452301U;
  ctx->buf[1] = 0xefcdab89U;
  ctx->buf[2] = 0x98badcfeU;
  ctx->buf[3] = 0x10325476U;

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


  if (IS_BIG_ENDIAN)
    ctx->doByteReverse = 1;
  else
    ctx->doByteReverse = 0;
}

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
static void MD5_Update(struct MD5Context* ctx, unsigned const char* 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);
    if (ctx->doByteReverse)
      byteReverse(ctx->in, 16);
    MD5_Transform(ctx->buf, (uint32*) ctx->in);
    buf += t;
    len -= t;
  }
  /* Process data in 64-byte chunks */

  while (len >= 64)
  {
    memcpy(ctx->in, buf, 64);
    if (ctx->doByteReverse)
      byteReverse(ctx->in, 16);
    MD5_Transform(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)
 */
static void MD5_Final(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);
    if (ctx->doByteReverse)
      byteReverse(ctx->in, 16);
    MD5_Transform(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);
  }
  if (ctx->doByteReverse)
    byteReverse(ctx->in, 14);

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

  MD5_Transform(ctx->buf, (uint32*) ctx->in);
  if (ctx->doByteReverse)
    byteReverse((unsigned char*) ctx->buf, 4);
  memcpy(digest, ctx->buf, 16);
  memset(ctx, 0, sizeof(struct MD5Context));  /* 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.  MD5_Update blocks
 * the data and converts bytes into longwords for this routine.
 */
static void MD5_Transform(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] + 0xd76aa478U, 7);
  MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756U, 12);
  MD5STEP(F1, c, d, a, b, in[2] + 0x242070dbU, 17);
  MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceeeU, 22);
  MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0fafU, 7);
  MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62aU, 12);
  MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613U, 17);
  MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501U, 22);
  MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8U, 7);
  MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7afU, 12);
  MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1U, 17);
  MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7beU, 22);
  MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122U, 7);
  MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193U, 12);
  MD5STEP(F1, c, d, a, b, in[14] + 0xa679438eU, 17);
  MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821U, 22);

  MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562U, 5);
  MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340U, 9);
  MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51U, 14);
  MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aaU, 20);
  MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105dU, 5);
  MD5STEP(F2, d, a, b, c, in[10] + 0x02441453U, 9);
  MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681U, 14);
  MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8U, 20);
  MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6U, 5);
  MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6U, 9);
  MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87U, 14);
  MD5STEP(F2, b, c, d, a, in[8] + 0x455a14edU, 20);
  MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905U, 5);
  MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8U, 9);
  MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9U, 14);
  MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8aU, 20);

  MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942U, 4);
  MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681U, 11);
  MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122U, 16);
  MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380cU, 23);
  MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44U, 4);
  MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9U, 11);
  MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60U, 16);
  MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70U, 23);
  MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6U, 4);
  MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127faU, 11);
  MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085U, 16);
  MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05U, 23);
  MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039U, 4);
  MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5U, 11);
  MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8U, 16);
  MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665U, 23);

  MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244U, 6);
  MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97U, 10);
  MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7U, 15);
  MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039U, 21);
  MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3U, 6);
  MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92U, 10);
  MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47dU, 15);
  MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1U, 21);
  MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4fU, 6);
  MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0U, 10);
  MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314U, 15);
  MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1U, 21);
  MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82U, 6);
  MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235U, 10);
  MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bbU, 15);
  MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391U, 21);

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

#endif


/*  function for very simple interface */
void raa_MD5String (char* in_string, char out_digest[33])
/*
   in_string: string to be MD5-digested
   out_digest: resulting digest as 32 hexadecimal digits plus final NULL
 */
{
  struct MD5Context context;
  unsigned int len = strlen (in_string);
  char* p;
  int i;
  unsigned char digest[16];

  MD5_Init (&context);
  MD5_Update (&context, (unsigned const char*)in_string, len);
  MD5_Final (digest, &context);

  p = out_digest;
  for (i = 0; i < 16; i++)
  {
    sprintf (p, "%02x", digest[i]);
    p += 2;
  }

  memset(&context, 0, sizeof(struct MD5Context));
}
