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 /*

  * 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 <string.h>

 #include "common/md5.h"

 namespace google_breakpad {

 #ifndef WORDS_BIGENDIAN

 #define byteReverse(buf, len)   /* Nothing */

 #else

 /*

  * Note: this code is harmless on little-endian machines.

  */

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

 {

   u32 t;

   do {

     t = (u32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |

       ((unsigned) buf[1] << 8 | buf[0]);

     *(u32 *) buf = t;

     buf += 4;

   } while (--longs);

 }

 #endif

 static void MD5Transform(u32 buf[4], u32 const in[16]);

 /*

  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious

  * initialization constants.

  */

 void MD5Init(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(struct MD5Context *ctx, unsigned char const *buf, unsigned len)

 {

   u32 t;

   /* Update bitcount */

   t = ctx->bits[0];

   if ((ctx->bits[0] = t + ((u32) 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, (u32 *) 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, (u32 *) 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(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, (u32 *) 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 */

   ((u32 *) ctx->in)[14] = ctx->bits[0];

   ((u32 *) ctx->in)[15] = ctx->bits[1];

   MD5Transform(ctx->buf, (u32 *) 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.

  */

 static void MD5Transform(u32 buf[4], u32 const in[16])

 {

   register u32 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;

 }

 }  // namespace google_breakpad