MD5HashAlgorithm_Licensed.h

// -*- tab-width: 2; indent-tabs-mode: nil; coding: utf-8-with-signature -*-
/* Functions to compute MD5 message digest of files or memory blocks.
   according to the definition of MD5 in RFC 1321 from April 1992.
   Copyright (C) 1995,1996,1997,1999,2000,2001 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
 
   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.
 
   The GNU C Library 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
   Lesser General Public License for more details.
 
   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; 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>, 1995.  */
 
#if defined(_M_IX86)
#  define WORDS_BIGENDIAN 1
#elif defined(ARCCORE_OS_LINUX)
#  include <endian.h>
#  include <stdint.h>
#  if __BYTE_ORDER == __BIG_ENDIAN
#    define WORDS_BIGENDIAN 1
#  endif
#elif defined(ARCCORE_OS_WIN32)
// Windows is on Intel CPU is little endian
#elif defined(ARCCORE_OS_MACOS)
// MacOS is on little endian (both i386 and ARM64)
# else
// i386 is little endian
#  if !defined(i386)
#    error "Doesn't know if target is little or big endian"
#  endif
#endif
 
#ifdef WORDS_BIGENDIAN
# define SWAP(n)              \
    (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
#else
# define SWAP(n) (n)
#endif
 
 
/* 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, ...  */ };
typedef unsigned int md5_uint32;
typedef uintptr_t md5_uintptr;
 
/* 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] __attribute__ ((__aligned__ (__alignof__ (md5_uint32))));
  char buffer[128];
};
 
static void _md5_process_block(const void *buffer,size_t len,md5_ctx *ctx);
static void _md5_process_bytes(const void *buffer,size_t len,md5_ctx *ctx);
 
 
/* Initialize structure containing state of computation.
   (RFC 1321, 3.3: Step 3)  */
static void
_md5_init_ctx(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;
}
 
/* Put result from CTX in first 16 bytes following RESBUF.  The result
   must be in little endian byte order.
 
   IMPORTANT: On some systems it is required that RESBUF is correctly
   aligned for a 32 bits value.  */
void*
_md5_read_ctx(const md5_ctx *ctx,void *resbuf)
{
  ((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;
}
 
/* 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(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;
  memcpy (&ctx->buffer[bytes], fillbuf, pad);
 
  /* 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);
 
  return _md5_read_ctx (ctx, resbuf);
}
 
 
/* 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.  */
static 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,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 += static_cast<md5_uint32>(add);
 
    if (ctx->buflen > 64)
    {
      _md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
 
      ctx->buflen &= 63;
      /* The regions in the following copy operation cannot overlap.  */
      memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
              ctx->buflen);
    }
 
    buffer = (const char *) buffer + add;
    len -= add;
  }
 
  /* Process available complete blocks.  */
  if (len >= 64)
  {
#if !_STRING_ARCH_unaligned
    /* To check alignment gcc has an appropriate operator.  Other
       compilers don't.  */
# if __GNUC__ >= 2
#  define UNALIGNED_P(p) (((md5_uintptr) p) % __alignof__ (md5_uint32) != 0)
# else
#  define UNALIGNED_P(p) (((md5_uintptr) p) % sizeof (md5_uint32) != 0)
# endif
    if (UNALIGNED_P (buffer))
      while (len > 64)
      {
        _md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
        buffer = (const char *) buffer + 64;
        len -= 64;
      }
    else
#endif
    {
      _md5_process_block (buffer, len & ~63, ctx);
      buffer = (const char *) buffer + (len & ~63);
      len &= 63;
    }
  }
 
  /* Move remaining bytes in internal buffer.  */
  if (len > 0)
  {
    size_t left_over = ctx->buflen;
 
    memcpy (&ctx->buffer[left_over], buffer, len);
    left_over += len;
    if (left_over >= 64)
    {
      _md5_process_block (ctx->buffer, 64, ctx);
      left_over -= 64;
      memcpy (ctx->buffer, &ctx->buffer[64], left_over);
    }
    ctx->buflen = static_cast<md5_uint32>(left_over);
  }
}
 
 
/* 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.  */
 
void
_md5_process_block(const void* buffer,size_t len,md5_ctx* ctx)
{
  md5_uint32 correct_words[16];
  const md5_uint32 *words = (const md5_uint32*)buffer;
  size_t nwords = len / sizeof (md5_uint32);
  const md5_uint32 *endp = words + nwords;
  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] += static_cast<md5_uint32>(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;
 
      /* 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.  */
#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
      */
 
      /* Round 1.  */
      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);
 
      /* 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.  */
      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);
 
      /* Round 3.  */
      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);
 
      /* Round 4.  */
      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);
 
      /* 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;
}