subversion/libsvn_subr/md5.c

   1 /*
   2  * md5.c:   checksum routines
   3  *
   4  * ====================================================================
   5  * Copyright (c) 2000-2004 CollabNet.  All rights reserved.
   6  *
   7  * This software is licensed as described in the file COPYING, which
   8  * you should have received as part of this distribution.  The terms
   9  * are also available at http://subversion.tigris.org/license-1.html.
  10  * If newer versions of this license are posted there, you may use a
  11  * newer version instead, at your option.
  12  *
  13  * This software consists of voluntary contributions made by many
  14  * individuals.  For exact contribution history, see the revision
  15  * history and logs, available at http://subversion.tigris.org/.
  16  * ====================================================================
  17  */
  18
  19
  20 #include "svn_md5.h"
  21
  22 \f
  23
  24 /* The MD5 digest for the empty string. */
  25 static const unsigned char svn_md5__empty_string_digest[] = {
  26   212, 29, 140, 217, 143, 0, 178, 4, 233, 128, 9, 152, 236, 248, 66, 126
  27 };
  28
  29 const unsigned char *
  30 svn_md5_empty_string_digest(void)
  31 {
  32   return svn_md5__empty_string_digest;
  33 }
  34
  35
  36 const char *
  37 svn_md5_digest_to_cstring_display(const unsigned char digest[],
  38                                   apr_pool_t *pool)
  39 {
  40   static const char *hex = "0123456789abcdef";
  41   char *str = apr_palloc(pool, (APR_MD5_DIGESTSIZE * 2) + 1);
  42   int i;
  43
  44   for (i = 0; i < APR_MD5_DIGESTSIZE; i++)
  45     {
  46       str[i*2]   = hex[digest[i] >> 4];
  47       str[i*2+1] = hex[digest[i] & 0x0f];
  48     }
  49   str[i*2] = '\0';
  50
  51   return str;
  52 }
  53
  54
  55 const char *
  56 svn_md5_digest_to_cstring(const unsigned char digest[], apr_pool_t *pool)
  57 {
  58   static const unsigned char zeros_digest[APR_MD5_DIGESTSIZE] = { 0 };
  59
  60   if (memcmp(digest, zeros_digest, APR_MD5_DIGESTSIZE) != 0)
  61     return svn_md5_digest_to_cstring_display(digest, pool);
  62   else
  63     return NULL;
  64 }
  65
  66
  67 svn_boolean_t
  68 svn_md5_digests_match(const unsigned char d1[], const unsigned char d2[])
  69 {
  70   static const unsigned char zeros[APR_MD5_DIGESTSIZE] = { 0 };
  71
  72   return ((memcmp(d1, zeros, APR_MD5_DIGESTSIZE) == 0)
  73           || (memcmp(d2, zeros, APR_MD5_DIGESTSIZE) == 0)
  74           || (memcmp(d1, d2, APR_MD5_DIGESTSIZE) == 0));
  75 }