src/TortoiseMerge/libsvn_diff/md5.c

   1 /*
   2  * md5.c:   checksum routines
   3  *
   4  * ====================================================================
   5  *    Licensed to the Apache Software Foundation (ASF) under one
   6  *    or more contributor license agreements.  See the NOTICE file
   7  *    distributed with this work for additional information
   8  *    regarding copyright ownership.  The ASF licenses this file
   9  *    to you under the Apache License, Version 2.0 (the
  10  *    "License"); you may not use this file except in compliance
  11  *    with the License.  You may obtain a copy of the License at
  12  *
  13  *      http://www.apache.org/licenses/LICENSE-2.0
  14  *
  15  *    Unless required by applicable law or agreed to in writing,
  16  *    software distributed under the License is distributed on an
  17  *    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  18  *    KIND, either express or implied.  See the License for the
  19  *    specific language governing permissions and limitations
  20  *    under the License.
  21  * ====================================================================
  22  */
  23
  24
  25 #include <apr_md5.h>
  26 #include "md5.h"
  27 #include "svn_md5.h"
  28
  29 \f
  30
  31 /* The MD5 digest for the empty string. */
  32 static const unsigned char svn_md5__empty_string_digest_array[] = {
  33   0xd4, 0x1d, 0x8c, 0xd9, 0x8f, 0x00, 0xb2, 0x04,
  34   0xe9, 0x80, 0x09, 0x98, 0xec, 0xf8, 0x42, 0x7e
  35 };
  36
  37 const unsigned char *
  38 svn_md5__empty_string_digest(void)
  39 {
  40   return svn_md5__empty_string_digest_array;
  41 }
  42
  43
  44 const char *
  45 svn_md5__digest_to_cstring_display(const unsigned char digest[],
  46                                    apr_pool_t *pool)
  47 {
  48   static const char *hex = "0123456789abcdef";
  49   char *str = apr_palloc(pool, (APR_MD5_DIGESTSIZE * 2) + 1);
  50   int i;
  51
  52   for (i = 0; i < APR_MD5_DIGESTSIZE; i++)
  53     {
  54       str[i*2]   = hex[digest[i] >> 4];
  55       str[i*2+1] = hex[digest[i] & 0x0f];
  56     }
  57   str[i*2] = '\0';
  58
  59   return str;
  60 }
  61
  62
  63 const char *
  64 svn_md5__digest_to_cstring(const unsigned char digest[], apr_pool_t *pool)
  65 {
  66   static const unsigned char zeros_digest[APR_MD5_DIGESTSIZE] = { 0 };
  67
  68   if (memcmp(digest, zeros_digest, APR_MD5_DIGESTSIZE) != 0)
  69     return svn_md5__digest_to_cstring_display(digest, pool);
  70   else
  71     return NULL;
  72 }
  73
  74
  75 svn_boolean_t
  76 svn_md5__digests_match(const unsigned char d1[], const unsigned char d2[])
  77 {
  78   static const unsigned char zeros[APR_MD5_DIGESTSIZE] = { 0 };
  79
  80   return ((memcmp(d1, zeros, APR_MD5_DIGESTSIZE) == 0)
  81           || (memcmp(d2, zeros, APR_MD5_DIGESTSIZE) == 0)
  82           || (memcmp(d1, d2, APR_MD5_DIGESTSIZE) == 0));
  83 }
  84
  85 /* These are all deprecated, and just wrap the internal functions defined
  86    above. */
  87 const unsigned char *
  88 svn_md5_empty_string_digest(void)
  89 {
  90   return svn_md5__empty_string_digest();
  91 }
  92
  93 const char *
  94 svn_md5_digest_to_cstring_display(const unsigned char digest[],
  95                                   apr_pool_t *pool)
  96 {
  97   return svn_md5__digest_to_cstring_display(digest, pool);
  98 }
  99
 100 const char *
 101 svn_md5_digest_to_cstring(const unsigned char digest[], apr_pool_t *pool)
 102 {
 103   return svn_md5__digest_to_cstring(digest, pool);
 104 }
 105
 106 svn_boolean_t
 107 svn_md5_digests_match(const unsigned char d1[], const unsigned char d2[])
 108 {
 109   return svn_md5__digests_match(d1, d2);
 110 }