src/md5.h

   1 /* Declaration of functions and data types used for MD5 sum computing
   2    library functions.
   3    Copyright (C) 1995, 1996, 1997, 1999, 2000 Free Software Foundation, Inc.
   4    This file is part of GNU Emacs.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #ifndef _MD5_H
  22 #define _MD5_H 1
  23
  24 #include <stdio.h>
  25
  26 #if defined HAVE_LIMITS_H || _LIBC
  27 # include <limits.h>
  28 #endif
  29
  30 /* The following contortions are an attempt to use the C preprocessor
  31    to determine an unsigned integral type that is 32 bits wide.  An
  32    alternative approach is to use autoconf's AC_CHECK_SIZEOF macro, but
  33    doing that would require that the configure script compile and *run*
  34    the resulting executable.  Locally running cross-compiled executables
  35    is usually not possible.  */
  36
  37 #ifdef _LIBC
  38 # include <sys/types.h>
  39 typedef u_int32_t md5_uint32;
  40 #else
  41 # if defined __STDC__ && __STDC__
  42 #  define UINT_MAX_32_BITS 4294967295U
  43 # else
  44 #  define UINT_MAX_32_BITS 0xFFFFFFFF
  45 # endif
  46
  47 /* If UINT_MAX isn't defined, assume it's a 32-bit type.
  48    This should be valid for all systems GNU cares about because
  49    that doesn't include 16-bit systems, and only modern systems
  50    (that certainly have <limits.h>) have 64+-bit integral types.  */
  51
  52 # ifndef UINT_MAX
  53 #  define UINT_MAX UINT_MAX_32_BITS
  54 # endif
  55
  56 # if UINT_MAX == UINT_MAX_32_BITS
  57    typedef unsigned int md5_uint32;
  58 # else
  59 #  if USHRT_MAX == UINT_MAX_32_BITS
  60     typedef unsigned short md5_uint32;
  61 #  else
  62 #   if ULONG_MAX == UINT_MAX_32_BITS
  63      typedef unsigned long md5_uint32;
  64 #   else
  65      /* The following line is intended to evoke an error.
  66         Using #error is not portable enough.  */
  67      "Cannot determine unsigned 32-bit data type."
  68 #   endif
  69 #  endif
  70 # endif
  71 #endif
  72
  73
  74 #ifndef __GNUC__
  75 #define __attribute__(X)
  76 #define __alignof__(X) 1
  77 #endif
  78
  79 /* Structure to save state of computation between the single steps.  */
  80 struct md5_ctx
  81 {
  82   md5_uint32 A;
  83   md5_uint32 B;
  84   md5_uint32 C;
  85   md5_uint32 D;
  86
  87   md5_uint32 total[2];
  88   md5_uint32 buflen;
  89   char buffer[128] __attribute__ ((__aligned__ (__alignof__ (md5_uint32))));
  90 };
  91
  92 /*
  93  * The following three functions are build up the low level used in
  94  * the functions `md5_stream' and `md5_buffer'.
  95  */
  96
  97 /* Initialize structure containing state of computation.
  98    (RFC 1321, 3.3: Step 3)  */
  99 extern void md5_init_ctx __P ((struct md5_ctx *ctx));
 100
 101 /* Starting with the result of former calls of this function (or the
 102    initialization function update the context for the next LEN bytes
 103    starting at BUFFER.
 104    It is necessary that LEN is a multiple of 64!!! */
 105 extern void md5_process_block __P ((const void *buffer, size_t len,
 106                                       struct md5_ctx *ctx));
 107
 108 /* Starting with the result of former calls of this function (or the
 109    initialization function update the context for the next LEN bytes
 110    starting at BUFFER.
 111    It is NOT required that LEN is a multiple of 64.  */
 112 extern void md5_process_bytes __P ((const void *buffer, size_t len,
 113                                       struct md5_ctx *ctx));
 114
 115 /* Process the remaining bytes in the buffer and put result from CTX
 116    in first 16 bytes following RESBUF.  The result is always in little
 117    endian byte order, so that a byte-wise output yields to the wanted
 118    ASCII representation of the message digest.
 119
 120    IMPORTANT: On some systems it is required that RESBUF is correctly
 121    aligned for a 32 bits value.  */
 122 extern void *md5_finish_ctx __P ((struct md5_ctx *ctx, void *resbuf));
 123
 124
 125 /* Put result from CTX in first 16 bytes following RESBUF.  The result is
 126    always in little endian byte order, so that a byte-wise output yields
 127    to the wanted ASCII representation of the message digest.
 128
 129    IMPORTANT: On some systems it is required that RESBUF is correctly
 130    aligned for a 32 bits value.  */
 131 extern void *md5_read_ctx __P ((const struct md5_ctx *ctx, void *resbuf));
 132
 133
 134 /* Compute MD5 message digest for bytes read from STREAM.  The
 135    resulting message digest number will be written into the 16 bytes
 136    beginning at RESBLOCK.  */
 137 extern int md5_stream __P ((FILE *stream, void *resblock));
 138
 139 /* Compute MD5 message digest for LEN bytes beginning at BUFFER.  The
 140    result is always in little endian byte order, so that a byte-wise
 141    output yields to the wanted ASCII representation of the message
 142    digest.  */
 143 extern void *md5_buffer __P ((const char *buffer, size_t len,
 144                                 void *resblock));
 145
 146 #endif /* md5.h */