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, 2001, 2002, 2003, 2004,
   4                  2005, 2006, 2007  Free Software Foundation, Inc.
   5    This file is part of GNU Emacs.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU General Public License as
   9    published by the Free Software Foundation; either version 2 of the
  10    License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public
  18    License along with the GNU C Library; see the file COPYING.  If not,
  19    write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20    Boston, MA 02110-1301, USA.  */
  21
  22 #ifndef _MD5_H
  23 #define _MD5_H 1
  24
  25 #include <stdio.h>
  26
  27 #if defined HAVE_LIMITS_H || _LIBC
  28 # include <limits.h>
  29 #endif
  30
  31 /* The following contortions are an attempt to use the C preprocessor
  32    to determine an unsigned integral type that is 32 bits wide.  An
  33    alternative approach is to use autoconf's AC_CHECK_SIZEOF macro, but
  34    doing that would require that the configure script compile and *run*
  35    the resulting executable.  Locally running cross-compiled executables
  36    is usually not possible.  */
  37
  38 #ifdef _LIBC
  39 # include <sys/types.h>
  40 typedef u_int32_t md5_uint32;
  41 #else
  42 # if defined __STDC__ && __STDC__
  43 #  define UINT_MAX_32_BITS 4294967295U
  44 # else
  45 #  define UINT_MAX_32_BITS 0xFFFFFFFF
  46 # endif
  47
  48 /* If UINT_MAX isn't defined, assume it's a 32-bit type.
  49    This should be valid for all systems GNU cares about because
  50    that doesn't include 16-bit systems, and only modern systems
  51    (that certainly have <limits.h>) have 64+-bit integral types.  */
  52
  53 # ifndef UINT_MAX
  54 #  define UINT_MAX UINT_MAX_32_BITS
  55 # endif
  56
  57 # if UINT_MAX == UINT_MAX_32_BITS
  58    typedef unsigned int md5_uint32;
  59 # else
  60 #  if USHRT_MAX == UINT_MAX_32_BITS
  61     typedef unsigned short md5_uint32;
  62 #  else
  63 #   if ULONG_MAX == UINT_MAX_32_BITS
  64      typedef unsigned long md5_uint32;
  65 #   else
  66      /* The following line is intended to evoke an error.
  67         Using #error is not portable enough.  */
  68      "Cannot determine unsigned 32-bit data type."
  69 #   endif
  70 #  endif
  71 # endif
  72 #endif
  73
  74
  75 #ifndef __GNUC__
  76 #define __attribute__(X)
  77 #define __alignof__(X) 1
  78 #endif
  79
  80 /* Structure to save state of computation between the single steps.  */
  81 struct md5_ctx
  82 {
  83   md5_uint32 A;
  84   md5_uint32 B;
  85   md5_uint32 C;
  86   md5_uint32 D;
  87
  88   md5_uint32 total[2];
  89   md5_uint32 buflen;
  90   char buffer[128] __attribute__ ((__aligned__ (__alignof__ (md5_uint32))));
  91 };
  92
  93 /*
  94  * The following three functions are build up the low level used in
  95  * the functions `md5_stream' and `md5_buffer'.
  96  */
  97
  98 /* Initialize structure containing state of computation.
  99    (RFC 1321, 3.3: Step 3)  */
 100 extern void md5_init_ctx (struct md5_ctx *ctx);
 101
 102 /* Starting with the result of former calls of this function (or the
 103    initialization function update the context for the next LEN bytes
 104    starting at BUFFER.
 105    It is necessary that LEN is a multiple of 64!!! */
 106 extern void md5_process_block (const void *buffer, size_t len,
 107                                struct md5_ctx *ctx);
 108
 109 /* Starting with the result of former calls of this function (or the
 110    initialization function update the context for the next LEN bytes
 111    starting at BUFFER.
 112    It is NOT required that LEN is a multiple of 64.  */
 113 extern void md5_process_bytes (const void *buffer, size_t len,
 114                                struct md5_ctx *ctx);
 115
 116 /* Process the remaining bytes in the buffer and put result from CTX
 117    in first 16 bytes following RESBUF.  The result is always in little
 118    endian byte order, so that a byte-wise output yields to the wanted
 119    ASCII representation of the message digest.
 120
 121    IMPORTANT: On some systems it is required that RESBUF is correctly
 122    aligned for a 32 bits value.  */
 123 extern void *md5_finish_ctx (struct md5_ctx *ctx, void *resbuf);
 124
 125
 126 /* Put result from CTX in first 16 bytes following RESBUF.  The result is
 127    always in little endian byte order, so that a byte-wise output yields
 128    to the wanted ASCII representation of the message digest.
 129
 130    IMPORTANT: On some systems it is required that RESBUF is correctly
 131    aligned for a 32 bits value.  */
 132 extern void *md5_read_ctx (const struct md5_ctx *ctx, void *resbuf);
 133
 134
 135 /* Compute MD5 message digest for bytes read from STREAM.  The
 136    resulting message digest number will be written into the 16 bytes
 137    beginning at RESBLOCK.  */
 138 extern int md5_stream (FILE *stream, void *resblock);
 139
 140 /* Compute MD5 message digest for LEN bytes beginning at BUFFER.  The
 141    result is always in little endian byte order, so that a byte-wise
 142    output yields to the wanted ASCII representation of the message
 143    digest.  */
 144 extern void *md5_buffer (const char *buffer, size_t len,
 145                          void *resblock);
 146
 147 #endif /* md5.h */
 148