path: root/md5.c

/* md5.c - Compute MD5 checksum of files or strings according to the
 *         definition of MD5 in RFC 1321 from April 1992.
 * Copyright (C) 1995-1999 Free Software Foundation, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu> */
/* Hacked to work with BusyBox by Alfred M. Szmidt <ams@trillian.itslinux.org> */

/* Sucked directly into ipkg since the md5sum functions aren't in libbb
   Dropped a few functions since ipkg only needs md5_stream.
   Got rid of evil, twisted defines of FALSE=1 and TRUE=0
   6 March 2002 Carl Worth <cworth@east.isi.edu>
*/

/*
 * June 29, 2001        Manuel Novoa III
 *
 * Added MD5SUM_SIZE_VS_SPEED configuration option.
 *
 * Current valid values, with data from my system for comparison, are:
 *   (using uClibc and running on linux-2.4.4.tar.bz2)
 *                     user times (sec)  text size (386)
 *     0 (fastest)         1.1                6144
 *     1                   1.4                5392
 *     2                   3.0                5088
 *     3 (smallest)        5.1                4912
 */

#define MD5SUM_SIZE_VS_SPEED 3

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

#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <getopt.h>
#include <stdlib.h>
#include <string.h>
#include <endian.h>
#include <sys/types.h>
#if defined HAVE_LIMITS_H
# include <limits.h>
#endif

#include "md5.h"

//----------------------------------------------------------------------------
//--------md5.c
//----------------------------------------------------------------------------

/* md5.c - Functions to compute MD5 message digest of files or memory blocks
 *         according to the definition of MD5 in RFC 1321 from April 1992.
 */

/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.  */

//----------------------------------------------------------------------------
//--------md5.h
//----------------------------------------------------------------------------

/* md5.h - Declaration of functions and data types used for MD5 sum
   computing library functions. */

typedef u_int32_t md5_uint32;

/* Structure to save state of computation between the single steps.  */
struct md5_ctx
{
  md5_uint32 A;
  md5_uint32 B;
  md5_uint32 C;
  md5_uint32 D;

  md5_uint32 total[2];
  md5_uint32 buflen;
  char buffer[128];
};

/*
 * The following three functions are build up the low level used in
 * the functions `md5_stream' and `md5_buffer'.
 */

/* Initialize structure containing state of computation.
   (RFC 1321, 3.3: Step 3)  */
static void md5_init_ctx __P ((struct md5_ctx *ctx));

/* Starting with the result of former calls of this function (or the
   initialization function update the context for the next LEN bytes
   starting at BUFFER.
   It is necessary that LEN is a multiple of 64!!! */
static void md5_process_block __P ((const void *buffer, size_t len,
				    struct md5_ctx *ctx));

/* Starting with the result of former calls of this function (or the
   initialization function update the context for the next LEN bytes
   starting at BUFFER.
   It is NOT required that LEN is a multiple of 64.  */
static void md5_process_bytes __P ((const void *buffer, size_t len,
				    struct md5_ctx *ctx));

/* Process the remaining bytes in the buffer and put result from CTX
   in first 16 bytes following RESBUF.  The result is always in little
   endian byte order, so that a byte-wise output yields to the wanted
   ASCII representation of the message digest.

   IMPORTANT: On some systems it is required that RESBUF is correctly
   aligned for a 32 bits value.  */
static void *md5_finish_ctx __P ((struct md5_ctx *ctx, void *resbuf));

//----------------------------------------------------------------------------
//--------end of md5.h
//----------------------------------------------------------------------------

/* Handle endian-ness */
#if __BYTE_ORDER == __LITTLE_ENDIAN
	#define SWAP(n) (n)
#else
	#define SWAP(n) ((n << 24) | ((n&65280)<<8) | ((n&16711680)>>8) | (n>>24))
#endif



#if MD5SUM_SIZE_VS_SPEED == 0
/* This array contains the bytes used to pad the buffer to the next
   64-byte boundary.  (RFC 1321, 3.1: Step 1)  */
static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ...  */  };
#endif

/* Initialize structure containing state of computation.
   (RFC 1321, 3.3: Step 3)  */
void md5_init_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;
}

/* Process the remaining bytes in the internal buffer and the usual
   prolog according to the standard and write the result to RESBUF.

   IMPORTANT: On some systems it is required that RESBUF is correctly
   aligned for a 32 bits value.  */
static void *md5_finish_ctx(struct md5_ctx *ctx, void *resbuf)
{
  /* Take yet unprocessed bytes into account.  */
  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;
#if MD5SUM_SIZE_VS_SPEED > 0
  memset(&ctx->buffer[bytes], 0, pad);
  ctx->buffer[bytes] = 0x80;
#else
  memcpy(&ctx->buffer[bytes], fillbuf, pad);
#endif

  /* 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);

/* Put result from CTX in first 16 bytes following RESBUF.  The result is
   always in little endian byte order, so that a byte-wise output yields
   to the wanted ASCII representation of the message digest.

   IMPORTANT: On some systems it is required that RESBUF is correctly
   aligned for a 32 bits value.  */
  ((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;
}

/* Compute MD5 message digest for bytes read from STREAM.  The
   resulting message digest number will be written into the 16 bytes
   beginning at RESBLOCK.  */
int md5_stream(FILE *stream, void *resblock)
{
  /* Important: BLOCKSIZE must be a multiple of 64.  */
static const int 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) {
    /* We read the file in blocks of BLOCKSIZE bytes.  One call of the
       computation function processes the whole buffer so that with the
       next round of the loop another block can be read.  */
    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;
}

/* Compute MD5 message digest for LEN bytes beginning at BUFFER.  The
   result is always in little endian byte order, so that a byte-wise
   output yields to the wanted ASCII representation of the message
   digest.  */
void *md5_buffer(const char *buffer, size_t len, void *resblock)
{
  struct md5_ctx ctx;

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

  /* Process whole buffer but last len % 64 bytes.  */
  md5_process_bytes(buffer, len, &ctx);

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

static void md5_process_bytes(const void *buffer, size_t len, struct md5_ctx *ctx)
{
  /* When we already have some bits in our internal buffer concatenate
     both inputs first.  */
  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);
      /* The regions in the following copy operation cannot overlap.  */
      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;
  }
}

/* These are the four functions used in the four steps of the MD5 algorithm
   and defined in the RFC 1321.  The first function is a little bit optimized
   (as found in Colin Plumbs public domain implementation).  */
/* #define FF(b, c, d) ((b & c) | (~b & d)) */
#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))

/* Process LEN bytes of BUFFER, accumulating context into CTX.
   It is assumed that LEN % 64 == 0.  */
static void md5_process_block(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;
#if MD5SUM_SIZE_VS_SPEED > 0
  static const md5_uint32 C_array[] = {
      /* round 1 */
      0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee,
      0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
      0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
      0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
      /* round 2 */
      0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
      0xd62f105d, 0x2441453,  0xd8a1e681, 0xe7d3fbc8,
      0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
      0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
      /* round 3 */
      0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,
      0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
      0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x4881d05,
      0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
      /* round 4 */
      0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039,
      0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
      0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
      0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391
  };

  static const char P_array[] = {
#if MD5SUM_SIZE_VS_SPEED > 1
      0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, /* 1 */
#endif
      1, 6, 11, 0, 5, 10, 15, 4, 9, 14, 3, 8, 13, 2, 7, 12, /* 2 */
      5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2, /* 3 */
      0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9  /* 4 */
  };

#if MD5SUM_SIZE_VS_SPEED > 1
  static const char S_array[] = {
      7, 12, 17, 22,
      5, 9, 14, 20,
      4, 11, 16, 23,
      6, 10, 15, 21
  };
#endif
#endif

  md5_uint32 A = ctx->A;
  md5_uint32 B = ctx->B;
  md5_uint32 C = ctx->C;
  md5_uint32 D = ctx->D;

  /* First increment the byte count.  RFC 1321 specifies the possible
     length of the file up to 2^64 bits.  Here we only compute the
     number of bytes.  Do a double word increment.  */
  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;

#if MD5SUM_SIZE_VS_SPEED > 1
#define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))

    const md5_uint32 *pc;
    const char *pp;
    const char *ps;
    int i;
    md5_uint32 temp;

    for ( i=0 ; i < 16 ; i++ ) {
	cwp[i] = SWAP(words[i]);
    }
    words += 16;

#if MD5SUM_SIZE_VS_SPEED > 2
    pc = C_array; pp = P_array; ps = S_array - 4;

    for ( i = 0 ; i < 64 ; i++ ) {
	if ((i&0x0f) == 0) ps += 4;
	temp = A;
	switch (i>>4) {
	    case 0:
		temp += FF(B,C,D);
		break;
	    case 1:
		temp += FG(B,C,D);
		break;
	    case 2:
		temp += FH(B,C,D);
		break;
	    case 3:
		temp += FI(B,C,D);
	}
	temp += cwp[(int)(*pp++)] + *pc++;
	temp = CYCLIC (temp, ps[i&3]);
	temp += B;
	A = D; D = C; C = B; B = temp;
    }
#else
    pc = C_array; pp = P_array; ps = S_array;

    for ( i = 0 ; i < 16 ; i++ ) {
	temp = A + FF(B,C,D) + cwp[(int)(*pp++)] + *pc++;
	temp = CYCLIC (temp, ps[i&3]);
	temp += B;
	A = D; D = C; C = B; B = temp;
    }

    ps += 4;
    for ( i = 0 ; i < 16 ; i++ ) {
	temp = A + FG(B,C,D) + cwp[(int)(*pp++)] + *pc++;
	temp = CYCLIC (temp, ps[i&3]);
	temp += B;
	A = D; D = C; C = B; B = temp;
    }
    ps += 4;
    for ( i = 0 ; i < 16 ; i++ ) {
	temp = A + FH(B,C,D) + cwp[(int)(*pp++)] + *pc++;
	temp = CYCLIC (temp, ps[i&3]);
	temp += B;
	A = D; D = C; C = B; B = temp;
    }
    ps += 4;
    for ( i = 0 ; i < 16 ; i++ ) {
	temp = A + FI(B,C,D) + cwp[(int)(*pp++)] + *pc++;
	temp = CYCLIC (temp, ps[i&3]);
	temp += B;
	A = D; D = C; C = B; B = temp;
    }

#endif
#else
    /* First round: using the given function, the context and a constant
       the next context is computed.  Because the algorithms processing
       unit is a 32-bit word and it is determined to work on words in
       little endian byte order we perhaps have to change the byte order
       before the computation.  To reduce the work for the next steps
       we store the swapped words in the array CORRECT_WORDS.  */

#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)

    /* It is unfortunate that C does not provide an operator for
       cyclic rotation.  Hope the C compiler is smart enough.  */
    /* gcc 2.95.4 seems to be --aaronl */
#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
    */

#if MD5SUM_SIZE_VS_SPEED == 1
    const md5_uint32 *pc;
    const char *pp;
    int i;
#endif

    /* Round 1.  */
#if MD5SUM_SIZE_VS_SPEED == 1
    pc = C_array;
    for ( i=0 ; i < 4 ; i++ ) {
	OP(A, B, C, D, 7, *pc++);
	OP(D, A, B, C, 12, *pc++);
	OP(C, D, A, B, 17, *pc++);
	OP(B, C, D, A, 22, *pc++);
    }
#else
    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);
#endif

    /* For the second to fourth round we have the possibly swapped words
       in CORRECT_WORDS.  Redefine the macro to take an additional first
       argument specifying the function to use.  */
#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.  */
#if MD5SUM_SIZE_VS_SPEED == 1
    pp = P_array;
    for ( i=0 ; i < 4 ; i++ ) {
	OP(FG, A, B, C, D, (int)(*pp++), 5, *pc++);
	OP(FG, D, A, B, C, (int)(*pp++), 9, *pc++);
	OP(FG, C, D, A, B, (int)(*pp++), 14, *pc++);
	OP(FG, B, C, D, A, (int)(*pp++), 20, *pc++);
    }
#else
    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);
#endif

    /* Round 3.  */
#if MD5SUM_SIZE_VS_SPEED == 1
    for ( i=0 ; i < 4 ; i++ ) {
	OP(FH, A, B, C, D, (int)(*pp++), 4, *pc++);
	OP(FH, D, A, B, C, (int)(*pp++), 11, *pc++);
	OP(FH, C, D, A, B, (int)(*pp++), 16, *pc++);
	OP(FH, B, C, D, A, (int)(*pp++), 23, *pc++);
    }
#else
    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);
#endif

    /* Round 4.  */
#if MD5SUM_SIZE_VS_SPEED == 1
    for ( i=0 ; i < 4 ; i++ ) {
	OP(FI, A, B, C, D, (int)(*pp++), 6, *pc++);
	OP(FI, D, A, B, C, (int)(*pp++), 10, *pc++);
	OP(FI, C, D, A, B, (int)(*pp++), 15, *pc++);
	OP(FI, B, C, D, A, (int)(*pp++), 21, *pc++);
    }
#else
    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);
#endif
#endif

    /* 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;
}

//----------------------------------------------------------------------------
//--------end of md5.c
//----------------------------------------------------------------------------

#define ISWHITE(c) ((c) == ' ' || (c) == '\t')
#define ISXDIGIT(c) (isxdigit (c))

/* The minimum length of a valid digest line in a file produced
   by `md5sum FILE' and read by `md5sum -c'.  This length does
   not include any newline character at the end of a line.  */
static const int MIN_DIGEST_LINE_LENGTH = 35; /* 32 - message digest length
                                      2 - blank and binary indicator
                                      1 - minimum filename length */

static inline int hex_digits(unsigned char const *s)
{
  while (*s) {
    if (!ISXDIGIT(*s))
      return 0;
    ++s;
  }
  return 1;
}