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   // filter out zero-length strings else we will underflow on len-1 below
50   if (len1 == 0 || len2 == 0) {
51     return 0.0;
52   }
53 
54   size_t total = len1 + len2;
55   size_t hit = 0;
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 }