xpcom/glue/nsVersionComparator.cpp

   1 /* ***** BEGIN LICENSE BLOCK *****
   2  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   3  *
   4  * The contents of this file are subject to the Mozilla Public License Version
   5  * 1.1 (the "License"); you may not use this file except in compliance with
   6  * the License. You may obtain a copy of the License at
   7  * http://www.mozilla.org/MPL/
   8  *
   9  * Software distributed under the License is distributed on an "AS IS" basis,
  10  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  11  * for the specific language governing rights and limitations under the
  12  * License.
  13  *
  14  * The Original Code is Mozilla XPCOM.
  15  *
  16  * The Initial Developer of the Original Code is
  17  * Benjamin Smedberg <benjamin@smedbergs.us>.
  18  *
  19  * Portions created by the Initial Developer are Copyright (C) 2005
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *
  24  * Alternatively, the contents of this file may be used under the terms of
  25  * either the GNU General Public License Version 2 or later (the "GPL"), or
  26  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  27  * in which case the provisions of the GPL or the LGPL are applicable instead
  28  * of those above. If you wish to allow use of your version of this file only
  29  * under the terms of either the GPL or the LGPL, and not to allow others to
  30  * use your version of this file under the terms of the MPL, indicate your
  31  * decision by deleting the provisions above and replace them with the notice
  32  * and other provisions required by the GPL or the LGPL. If you do not delete
  33  * the provisions above, a recipient may use your version of this file under
  34  * the terms of any one of the MPL, the GPL or the LGPL.
  35  *
  36  * ***** END LICENSE BLOCK ***** */
  37
  38 #include "nsVersionComparator.h"
  39
  40 #include <stdlib.h>
  41 #include <string.h>
  42
  43 struct VersionPart {
  44   PRInt32     numA;
  45
  46   const char *strB;    // NOT null-terminated, can be a null pointer
  47   PRUint32    strBlen;
  48
  49   PRInt32     numC;
  50
  51   char       *extraD;  // null-terminated
  52 };
  53
  54 /**
  55  * Parse a version part into a number and "extra text".
  56  *
  57  * @returns A pointer to the next versionpart, or null if none.
  58  */
  59 static char*
  60 ParseVP(char *part, VersionPart &result)
  61 {
  62   char *dot;
  63
  64   result.numA = 0;
  65   result.strB = nsnull;
  66   result.strBlen = 0;
  67   result.numC = 0;
  68   result.extraD = nsnull;
  69
  70   if (!part)
  71     return part;
  72
  73   dot = strchr(part, '.');
  74   if (dot)
  75     *dot = '\0';
  76
  77   if (part[0] == '*' && part[1] == '\0') {
  78     result.numA = PR_INT32_MAX;
  79     result.strB = "";
  80   }
  81   else {
  82     result.numA = strtol(part, const_cast<char**>(&result.strB), 10);
  83   }
  84
  85   if (!*result.strB) {
  86     result.strB = nsnull;
  87     result.strBlen = 0;
  88   }
  89   else {
  90     if (result.strB[0] == '+') {
  91       static const char kPre[] = "pre";
  92
  93       ++result.numA;
  94       result.strB = kPre;
  95       result.strBlen = sizeof(kPre) - 1;
  96     }
  97     else {
  98       const char *numstart = strpbrk(result.strB, "0123456789+-");
  99       if (!numstart) {
 100         result.strBlen = strlen(result.strB);
 101       }
 102       else {
 103         result.strBlen = numstart - result.strB;
 104
 105         result.numC = strtol(numstart, &result.extraD, 10);
 106         if (!*result.extraD)
 107           result.extraD = nsnull;
 108       }
 109     }
 110   }
 111
 112   if (dot) {
 113     ++dot;
 114
 115     if (!*dot)
 116       dot = nsnull;
 117   }
 118
 119   return dot;
 120 }
 121
 122 // compare two null-terminated strings, which may be null pointers
 123 static PRInt32
 124 ns_strcmp(const char *str1, const char *str2)
 125 {
 126   // any string is *before* no string
 127   if (!str1)
 128     return str2 != 0;
 129
 130   if (!str2)
 131     return -1;
 132
 133   return strcmp(str1, str2);
 134 }
 135
 136 // compare two length-specified string, which may be null pointers
 137 static PRInt32
 138 ns_strnncmp(const char *str1, PRUint32 len1, const char *str2, PRUint32 len2)
 139 {
 140   // any string is *before* no string
 141   if (!str1)
 142     return str2 != 0;
 143
 144   if (!str2)
 145     return -1;
 146
 147   for (; len1 && len2; --len1, --len2, ++str1, ++str2) {
 148     if (*str1 < *str2)
 149       return -1;
 150
 151     if (*str1 > *str2)
 152       return 1;
 153   }
 154
 155   if (len1 == 0)
 156     return len2 == 0 ? 0 : -1;
 157
 158   return 1;
 159 }
 160
 161 // compare two PRInt32
 162 static PRInt32
 163 ns_cmp(PRInt32 n1, PRInt32 n2)
 164 {
 165   if (n1 < n2)
 166     return -1;
 167
 168   return n1 != n2;
 169 }
 170
 171 /**
 172  * Compares two VersionParts
 173  */
 174 static PRInt32
 175 CompareVP(VersionPart &v1, VersionPart &v2)
 176 {
 177   PRInt32 r = ns_cmp(v1.numA, v2.numA);
 178   if (r)
 179     return r;
 180
 181   r = ns_strnncmp(v1.strB, v1.strBlen, v2.strB, v2.strBlen);
 182   if (r)
 183     return r;
 184
 185   r = ns_cmp(v1.numC, v2.numC);
 186   if (r)
 187     return r;
 188
 189   return ns_strcmp(v1.extraD, v2.extraD);
 190 }
 191
 192 PRInt32
 193 NS_CompareVersions(const char *A, const char *B)
 194 {
 195   char *A2 = strdup(A);
 196   if (!A2)
 197     return 1;
 198
 199   char *B2 = strdup(B);
 200   if (!B2) {
 201     free(A2);
 202     return 1;
 203   }
 204
 205   PRInt32 result;
 206   char *a = A2, *b = B2;
 207
 208   do {
 209     VersionPart va, vb;
 210
 211     a = ParseVP(a, va);
 212     b = ParseVP(b, vb);
 213
 214     result = CompareVP(va, vb);
 215     if (result)
 216       break;
 217
 218   } while (a || b);
 219
 220   free(A2);
 221   free(B2);
 222
 223   return result;
 224 }
 225