lib/md5.h

   1 /* md5.h - Declaration of functions and data types used for MD5 sum
   2    computing library functions.
   3    Copyright (C) 1995 Free Software Foundation, Inc.
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation; either version 2, or (at your option)
   8 any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  18
  19 #ifndef _MD5_H
  20 #define _MD5_H
  21
  22 #include <stdio.h>
  23
  24 #if defined HAVE_LIMITS_H || _LIBC
  25 # include <limits.h>
  26 #endif
  27
  28 /* The following contortions are an attempt to use the C preprocessor
  29    to determine an unsigned integral type that is 32 bits wide.  An
  30    alternative approach is to use autoconf's AC_CHECK_SIZEOF macro, but
  31    doing that would require that the configure script compile and *run*
  32    the resulting executable.  Locally running cross-compiled executables
  33    is usually not possible.  */
  34
  35 #if defined __STDC__ && __STDC__
  36 # define UINT_MAX_32_BITS 4294967295U
  37 #else
  38 # define UINT_MAX_32_BITS 0xFFFFFFFF
  39 #endif
  40
  41 /* If UINT_MAX isn't defined, assume it's a 32-bit type.
  42    This should be valid for all systems GNU cares about because
  43    that doesn't include 16-bit systems, and only modern systems
  44    (that certainly have <limits.h>) have 64+-bit integral types.  */
  45
  46 #ifndef UINT_MAX
  47 # define UINT_MAX UINT_MAX_32_BITS
  48 #endif
  49
  50 #if UINT_MAX == UINT_MAX_32_BITS
  51   typedef unsigned int md5_uint32;
  52 #else
  53 # if USHRT_MAX == UINT_MAX_32_BITS
  54    typedef unsigned short md5_uint32;
  55 # else
  56 #  if ULONG_MAX == UINT_MAX_32_BITS
  57     typedef unsigned long md5_uint32;
  58 #  else
  59     /* The following line is intended to evoke an error.
  60        Using #error is not portable enough.  */
  61     "Cannot determine unsigned 32-bit data type."
  62 #  endif
  63 # endif
  64 #endif
  65
  66 #undef __P
  67 #if defined (__STDC__) && __STDC__
  68 #define __P(x) x
  69 #else
  70 #define __P(x) ()
  71 #endif
  72
  73 /* Structure to save state of computation between the single steps.  */
  74 struct md5_ctx
  75 {
  76   md5_uint32 A;
  77   md5_uint32 B;
  78   md5_uint32 C;
  79   md5_uint32 D;
  80 };
  81
  82 /*
  83  * The following three functions are build up the low level used in
  84  * the functions `md5_stream' and `md5_buffer'.
  85  */
  86
  87 /* Initialize structure containing state of computation.
  88    (RFC 1321, 3.3: Step 3)  */
  89 void md5_init_ctx __P ((struct md5_ctx *ctx));
  90
  91 /* Starting with the result of former calls of this function (or the
  92    initialzation function update the context for the next LEN bytes
  93    starting at BUFFER.
  94    It is necessary that LEN is a multiple of 64!!! */
  95 void md5_process_block __P ((const void *buffer, size_t len,
  96                              struct md5_ctx *ctx));
  97
  98 /* Put result from CTX in first 16 bytes following RESBUF.  The result is
  99    always in little endian byte order, so that a byte-wise output yields
 100    to the wanted ASCII representation of the message digest.  */
 101 void *md5_read_ctx __P ((const struct md5_ctx *ctx, void *resbuf));
 102
 103
 104 /* Compute MD5 message digest for bytes read from STREAM.  The
 105    resulting message digest number will be written into the 16 bytes
 106    beginning at RESBLOCK.  */
 107 int md5_stream __P ((FILE *stream, void *resblock));
 108
 109 /* Compute MD5 message digest for LEN bytes beginning at BUFFER.  The
 110    result is always in little endian byte order, so that a byte-wise
 111    output yields to the wanted ASCII representation of the message
 112    digest.  */
 113 void *md5_buffer __P ((const char *buffer, size_t len, void *resblock));
 114
 115 #endif