/*------------------------------------------------------------------
 * MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm
 * Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991.
 * All rights reserved.
 *------------------------------------------------------------------
 * License to copy and use this software is granted provided that it
 * is identified as the "RSA Data Security, Inc. MD5 Message-Digest
 * Algorithm" in all material mentioning or referencing this software
 * or this function.
 *
 * License is also granted to make and use derivative works provided
 * that such works are identified as "derived from the RSA Data
 * Security, Inc. MD5 Message-Digest Algorithm" in all material
 * mentioning or referencing the derived work.
 *
 * RSA Data Security, Inc. makes no representations concerning either
 * the merchantability of this software or the suitability of this
 * software for any particular purpose. It is provided "as is"
 * without express or implied warranty of any kind.
 *
 * These notices must be retained in any copies of any part of this
 * documentation and/or software.
 *------------------------------------------------------------------
 * The sources have been edited from the original to conform to the
 * overall coding style, and to fit with the rest of the program.
 * The actual encryption code hasn't been touched.
 *------------------------------------------------------------------
 */

#include "machine.h"
#include "md5.h"

#include <string.h>

/*--------------------------------------------------------------------*/
/* Forward declarations */

static void MD5Transform(unsigned long int [4], unsigned char [64]);
static void Encode(unsigned char *, unsigned long int *, unsigned int);
static void Decode(unsigned long int *, unsigned char *, unsigned int);
static void MD5_memcpy(unsigned char *, unsigned char *, unsigned int);
static void MD5_memset(unsigned char *, int, unsigned int);

/*--------------------------------------------------------------------*/
/* Constants for MD5Transform routine.
 */

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

static unsigned char PADDING[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
};

/* F, G, H and I are basic MD5 functions.
 */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits.
 */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
 * Rotation is separate from addition to prevent recomputation.
 */
#define FF(a, b, c, d, x, s, ac) { \
 (a) += F ((b), (c), (d)) + (x) + (unsigned long int)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define GG(a, b, c, d, x, s, ac) { \
 (a) += G ((b), (c), (d)) + (x) + (unsigned long int)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define HH(a, b, c, d, x, s, ac) { \
 (a) += H ((b), (c), (d)) + (x) + (unsigned long int)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define II(a, b, c, d, x, s, ac) { \
 (a) += I ((b), (c), (d)) + (x) + (unsigned long int)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }

/*--------------------------------------------------------------------*/
void
MD5Init (MD5_CTX *context)

/* MD5 initialization. Begins an MD5 operation, writing a new context.
 */

{
    context->count[0] = context->count[1] = 0;
    /* Load magic initialization constants. */
    context->state[0] = 0x67452301;
    context->state[1] = 0xefcdab89;
    context->state[2] = 0x98badcfe;
    context->state[3] = 0x10325476;
} /* MD5Init() */

/*--------------------------------------------------------------------*/
void
MD5Update (MD5_CTX *context, unsigned char *input, unsigned int inputLen)

/* MD5 block update operation. Continues an MD5 message-digest
 * operation, processing another message block, and updating the
 * context.
 */

{
    unsigned int i, ix, partLen;

    /* Compute number of bytes mod 64 */
    ix = (unsigned int)((context->count[0] >> 3) & 0x3F);

    /* Update number of bits */
    if (  (context->count[0] += ((unsigned long int)inputLen << 3))
        < ((unsigned long int)inputLen << 3))
        context->count[1]++;

    context->count[1] += ((unsigned long int)inputLen >> 29);

    partLen = 64 - ix;

    /* Transform as many times as possible. */
    if (inputLen >= partLen)
    {
        MD5_memcpy((unsigned char *)&context->buffer[ix]
                  , (unsigned char *)input, partLen);
        MD5Transform (context->state, context->buffer);

        for (i = partLen; i + 63 < inputLen; i += 64)
            MD5Transform (context->state, &input[i]);
        ix = 0;
    }
    else
        i = 0;

    /* Buffer remaining input */
    MD5_memcpy((unsigned char *)&context->buffer[ix]
              , (unsigned char *)&input[i], inputLen-i);
} /* MD5Update() */

/*--------------------------------------------------------------------*/
void
MD5Final (MD5_CTX *context, unsigned char digest[16])

/* MD5 finalization. Ends an MD5 message-digest operation, writing the
 * the message digest and zeroizing the context.
 */

{
    unsigned char bits[8];
    unsigned int ix, padLen;

    /* Save number of bits */
    Encode (bits, context->count, 8);

    /* Pad out to 56 mod 64. */
    ix = (unsigned int)((context->count[0] >> 3) & 0x3f);
    padLen = (ix < 56) ? (56 - ix) : (120 - ix);
    MD5Update (context, PADDING, padLen);

    /* Append length (before padding) */
    MD5Update (context, bits, 8);

    /* Store state in digest */
    Encode (digest, context->state, 16);

    /* Zeroize sensitive information. */
    MD5_memset ((unsigned char *)context, 0, sizeof (*context));
} /* MD5Final() */

/*--------------------------------------------------------------------*/
static void
MD5Transform (unsigned long int state[4], unsigned char block[64])

/* MD5 basic transformation. Transforms state based on block.
 */

{
    unsigned long int a = state[0], b = state[1], c = state[2], d = state[3], x[16];

    Decode (x, block, 64);

    /* Round 1 */
    FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
    FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
    FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
    FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
    FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
    FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
    FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
    FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
    FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
    FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
    FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
    FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
    FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
    FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
    FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
    FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

   /* Round 2 */
    GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
    GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
    GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
    GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
    GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
    GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
    GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
    GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
    GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
    GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
    GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */

    GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
    GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
    GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
    GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
    GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

    /* Round 3 */
    HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
    HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
    HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
    HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
    HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
    HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
    HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
    HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
    HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
    HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
    HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
    HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
    HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
    HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
    HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
    HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

    /* Round 4 */
    II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
    II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
    II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
    II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
    II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
    II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
    II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
    II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
    II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
    II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
    II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
    II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
    II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
    II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
    II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
    II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

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

    /* Zeroize sensitive information. */
    MD5_memset ((unsigned char *)x, 0, sizeof (x));
} /* MD5Transform() */

/*--------------------------------------------------------------------*/
static void
Encode (unsigned char *output, unsigned long int *input, unsigned int len)

/* Encodes input (unsigned long int) into output (unsigned char). Assumes len is
 * a multiple of 4.
 */

{
    unsigned int i, j;

    for (i = 0, j = 0; j < len; i++, j += 4) {
        output[j] = (unsigned char)(input[i] & 0xff);
        output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
        output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
        output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
    }
} /* Encode() */

/*--------------------------------------------------------------------*/
static void
Decode (unsigned long int *output, unsigned char *input, unsigned int len)

/* Decodes input (unsigned char) into output (unsigned long int). Assumes len is
 * a multiple of 4.
 */

{
    unsigned int i, j;

    for (i = 0, j = 0; j < len; i++, j += 4)
        output[i] =  ((unsigned long int)input[j])
                   | (((unsigned long int)input[j+1]) << 8)
                   | (((unsigned long int)input[j+2]) << 16)
                   | (((unsigned long int)input[j+3]) << 24);
} /* Decode() */

/*--------------------------------------------------------------------*/
static void
MD5_memcpy (unsigned char * output, unsigned char * input, unsigned int len)

/* Portability function.
 */

{
#ifdef HAVE_MEMCPY
    memcpy(output, input, len);
#else
    unsigned int i;

    for (i = 0; i < len; i++)  output[i] = input[i];
#endif
} /* MD5_memcpy() */

/*--------------------------------------------------------------------*/
static void
MD5_memset (unsigned char * output, int value, unsigned int len)

/* Portability function.
 */

{
#ifdef HAVE_MEMSET
    memset(output, value, len);
#else
    unsigned int i;

    for (i = 0; i < len; i++)
        ((char *)output)[i] = (char)value;
#endif
} /* MD5_memset() */

/***************************************************************************/