1 /*
   2  * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "utilities/debug.hpp"
  27 #include "utilities/stringUtils.hpp"
  28 
  29 int StringUtils::replace_no_expand(char* string, const char* from, const char* to) {
  30   int replace_count = 0;
  31   size_t from_len = strlen(from);
  32   size_t to_len = strlen(to);
  33   assert(from_len >= to_len, "must not expand input");
  34 
  35   for (char* dst = string; *dst && (dst = strstr(dst, from)) != NULL;) {
  36     char* left_over = dst + from_len;
  37     memmove(dst, to, to_len);                       // does not copy trailing 0 of <to>
  38     dst += to_len;                                  // skip over the replacement.
  39     memmove(dst, left_over, strlen(left_over) + 1); // copies the trailing 0 of <left_over>
  40     ++ replace_count;
  41   }
  42 
  43   return replace_count;
  44 }
  45 
  46 double StringUtils::similarity(const char* str1, size_t len1, const char* str2, size_t len2) {
  47   assert(str1 != NULL && str2 != NULL, "sanity");
  48 
  49   size_t total = len1 + len2;
  50   size_t hit = 0;
  51 
  52   // filter out zero-length strings else we will underflow on len-1 below
  53   if (len1 == 0 || len2 == 0) {
  54     return 0.0;
  55   }
  56 
  57   for (size_t i = 0; i < len1 - 1; i++) {
  58     for (size_t j = 0; j < len2 - 1; j++) {
  59       if ((str1[i] == str2[j]) && (str1[i+1] == str2[j+1])) {
  60         ++hit;
  61         break;
  62       }
  63     }
  64   }
  65 
  66   return 2.0 * (double) hit / (double) total;
  67 }