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 #else
  41 #  define INT_MAX_32_BITS 2147483647
  42
  43 /* If UINT_MAX isn't defined, assume it's a 32-bit type.
  44    This should be valid for all systems GNU cares about because
  45    that doesn't include 16-bit systems, and only modern systems
  46    (that certainly have <limits.h>) have 64+-bit integral types.  */
  47
  48 # ifndef INT_MAX
  49 #  define INT_MAX INT_MAX_32_BITS
  50 # endif
  51
  52 # if INT_MAX == INT_MAX_32_BITS
  53    typedef unsigned int md5_uint32;
  54 # else
  55 #  if SHRT_MAX == INT_MAX_32_BITS
  56     typedef unsigned short md5_uint32;
  57 #  else
  58 #   if LONG_MAX == INT_MAX_32_BITS
  59      typedef unsigned long md5_uint32;
  60 #   else
  61      /* The following line is intended to evoke an error.
  62         Using #error is not portable enough.  */
  63      "Cannot determine unsigned 32-bit data type."
  64 #   endif
  65 #  endif
  66 # endif
  67 #endif
  68
  69 /* Structure to save state of computation between the single steps.  */
  70 struct md5_ctx
  71 {
  72   md5_uint32 A;
  73   md5_uint32 B;
  74   md5_uint32 C;
  75   md5_uint32 D;
  76
  77   md5_uint32 total[2];
  78   md5_uint32 buflen;
  79   char buffer[128];
  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 extern void md5_init_ctx (struct md5_ctx *ctx);
  90
  91 /* Starting with the result of former calls of this function (or the
  92    initialization 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 extern void md5_process_block (const void *buffer, size_t len,
  96                                struct md5_ctx *ctx);
  97
  98 /* Starting with the result of former calls of this function (or the
  99    initialization function update the context for the next LEN bytes
 100    starting at BUFFER.
 101    It is NOT required that LEN is a multiple of 64.  */
 102 extern void md5_process_bytes (const void *buffer, size_t len,
 103                                struct md5_ctx *ctx);
 104
 105 /* Process the remaining bytes in the buffer and put result from CTX
 106    in first 16 bytes following RESBUF.  The result is always in little
 107    endian byte order, so that a byte-wise output yields to the wanted
 108    ASCII representation of the message digest.
 109
 110    IMPORTANT: On some systems it is required that RESBUF is correctly
 111    aligned for a 32 bits value.  */
 112 extern void *md5_finish_ctx (struct md5_ctx *ctx, void *resbuf);
 113
 114
 115 /* Put result from CTX in first 16 bytes following RESBUF.  The result is
 116    always in little endian byte order, so that a byte-wise output yields
 117    to the wanted ASCII representation of the message digest.
 118
 119    IMPORTANT: On some systems it is required that RESBUF is correctly
 120    aligned for a 32 bits value.  */
 121 extern void *md5_read_ctx (const struct md5_ctx *ctx, void *resbuf);
 122
 123
 124 /* Compute MD5 message digest for bytes read from STREAM.  The
 125    resulting message digest number will be written into the 16 bytes
 126    beginning at RESBLOCK.  */
 127 extern int md5_stream (FILE *stream, void *resblock);
 128
 129 /* Compute MD5 message digest for LEN bytes beginning at BUFFER.  The
 130    result is always in little endian byte order, so that a byte-wise
 131    output yields to the wanted ASCII representation of the message
 132    digest.  */
 133 extern void *md5_buffer (const char *buffer, size_t len, void *resblock);
 134
 135 #endif