include/md5.h

   1 /* md5.h - Declaration of functions and data types used for MD5 sum
   2    computing library functions.
   3    Copyright 1995, 1996, 2000 Free Software Foundation, Inc.
   4    NOTE: The canonical source of this file is maintained with the GNU C
   5    Library.  Bugs can be reported to bug-glibc@prep.ai.mit.edu.
   6
   7    This program is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published by the
   9    Free Software Foundation; either version 2, or (at your option) any
  10    later version.
  11
  12    This program 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
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software Foundation,
  19    Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, 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 typedef uintptr_t md5_uintptr;
  41 #else
  42 #  define INT_MAX_32_BITS 2147483647
  43
  44 /* If UINT_MAX isn't defined, assume it's a 32-bit type.
  45    This should be valid for all systems GNU cares about because
  46    that doesn't include 16-bit systems, and only modern systems
  47    (that certainly have <limits.h>) have 64+-bit integral types.  */
  48
  49 # ifndef INT_MAX
  50 #  define INT_MAX INT_MAX_32_BITS
  51 # endif
  52
  53 # if INT_MAX == INT_MAX_32_BITS
  54    typedef unsigned int md5_uint32;
  55 # else
  56 #  if SHRT_MAX == INT_MAX_32_BITS
  57     typedef unsigned short md5_uint32;
  58 #  else
  59 #   if LONG_MAX == INT_MAX_32_BITS
  60      typedef unsigned long md5_uint32;
  61 #   else
  62      /* The following line is intended to evoke an error.
  63         Using #error is not portable enough.  */
  64      "Cannot determine unsigned 32-bit data type."
  65 #   endif
  66 #  endif
  67 # endif
  68 /* We have to make a guess about the integer type equivalent in size
  69    to pointers which should always be correct.  */
  70 typedef unsigned long int md5_uintptr;
  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   md5_uint32 total[2];
  82   md5_uint32 buflen;
  83   char buffer[128] ATTRIBUTE_ALIGNED_ALIGNOF(md5_uint32);
  84 };
  85
  86 /*
  87  * The following three functions are build up the low level used in
  88  * the functions `md5_stream' and `md5_buffer'.
  89  */
  90
  91 /* Initialize structure containing state of computation.
  92    (RFC 1321, 3.3: Step 3)  */
  93 extern void md5_init_ctx (struct md5_ctx *ctx);
  94
  95 /* Starting with the result of former calls of this function (or the
  96    initialization function update the context for the next LEN bytes
  97    starting at BUFFER.
  98    It is necessary that LEN is a multiple of 64!!! */
  99 extern void md5_process_block (const void *buffer, size_t len,
 100                                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 NOT required that LEN is a multiple of 64.  */
 106 extern void md5_process_bytes (const void *buffer, size_t len,
 107                                struct md5_ctx *ctx);
 108
 109 /* Process the remaining bytes in the buffer and put result from CTX
 110    in first 16 bytes following RESBUF.  The result is always in little
 111    endian byte order, so that a byte-wise output yields to the wanted
 112    ASCII representation of the message digest.
 113
 114    IMPORTANT: On some systems it is required that RESBUF is correctly
 115    aligned for a 32 bits value.  */
 116 extern void *md5_finish_ctx (struct md5_ctx *ctx, void *resbuf);
 117
 118
 119 /* Put result from CTX in first 16 bytes following RESBUF.  The result is
 120    always in little endian byte order, so that a byte-wise output yields
 121    to the wanted ASCII representation of the message digest.
 122
 123    IMPORTANT: On some systems it is required that RESBUF is correctly
 124    aligned for a 32 bits value.  */
 125 extern void *md5_read_ctx (const struct md5_ctx *ctx, void *resbuf);
 126
 127
 128 /* Compute MD5 message digest for bytes read from STREAM.  The
 129    resulting message digest number will be written into the 16 bytes
 130    beginning at RESBLOCK.  */
 131 extern int md5_stream (FILE *stream, void *resblock);
 132
 133 /* Compute MD5 message digest for LEN bytes beginning at BUFFER.  The
 134    result is always in little endian byte order, so that a byte-wise
 135    output yields to the wanted ASCII representation of the message
 136    digest.  */
 137 extern void *md5_buffer (const char *buffer, size_t len, void *resblock);
 138
 139 #endif