1 /* Test of searching in a string.
2    Copyright (C) 2007-2020 Free Software Foundation, Inc.
3 
4    This program is free software: you can redistribute it and/or modify
5    it under the terms of the GNU General Public License as published by
6    the Free Software Foundation; either version 3 of the License, or
7    (at your option) any later version.
8 
9    This program is distributed in the hope that it will be useful,
10    but WITHOUT ANY WARRANTY; without even the implied warranty of
11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12    GNU General Public License for more details.
13 
14    You should have received a copy of the GNU General Public License
15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
16 
17 /* Written by Bruno Haible <bruno@clisp.org>, 2007.  */
18 
19 #include <config.h>
20 
21 #include "c-strstr.h"
22 
23 #include <stdlib.h>
24 #include <string.h>
25 
26 #include "macros.h"
27 
28 int
main()29 main ()
30 {
31   {
32     const char input[] = "foo";
33     const char *result = c_strstr (input, "");
34     ASSERT (result == input);
35   }
36 
37   {
38     const char input[] = "foo";
39     const char *result = c_strstr (input, "o");
40     ASSERT (result == input + 1);
41   }
42 
43   {
44     const char input[] = "ABC ABCDAB ABCDABCDABDE";
45     const char *result = c_strstr (input, "ABCDABD");
46     ASSERT (result == input + 15);
47   }
48 
49   {
50     const char input[] = "ABC ABCDAB ABCDABCDABDE";
51     const char *result = c_strstr (input, "ABCDABE");
52     ASSERT (result == NULL);
53   }
54 
55   /* Check that a very long haystack is handled quickly if the needle is
56      short and occurs near the beginning.  */
57   {
58     size_t repeat = 10000;
59     size_t m = 1000000;
60     const char *needle =
61       "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
62       "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
63     char *haystack = (char *) malloc (m + 1);
64     if (haystack != NULL)
65       {
66         memset (haystack, 'A', m);
67         haystack[0] = 'B';
68         haystack[m] = '\0';
69 
70         for (; repeat > 0; repeat--)
71           {
72             ASSERT (c_strstr (haystack, needle) == haystack + 1);
73           }
74 
75         free (haystack);
76       }
77   }
78 
79   /* Check that a very long needle is discarded quickly if the haystack is
80      short.  */
81   {
82     size_t repeat = 10000;
83     size_t m = 1000000;
84     const char *haystack =
85       "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
86       "ABABABABABABABABABABABABABABABABABABABABABABABABABABABABABABABABABAB";
87     char *needle = (char *) malloc (m + 1);
88     if (needle != NULL)
89       {
90         memset (needle, 'A', m);
91         needle[m] = '\0';
92 
93         for (; repeat > 0; repeat--)
94           {
95             ASSERT (c_strstr (haystack, needle) == NULL);
96           }
97 
98         free (needle);
99       }
100   }
101 
102   /* Check that the asymptotic worst-case complexity is not quadratic.  */
103   {
104     size_t m = 1000000;
105     char *haystack = (char *) malloc (2 * m + 2);
106     char *needle = (char *) malloc (m + 2);
107     if (haystack != NULL && needle != NULL)
108       {
109         const char *result;
110 
111         memset (haystack, 'A', 2 * m);
112         haystack[2 * m] = 'B';
113         haystack[2 * m + 1] = '\0';
114 
115         memset (needle, 'A', m);
116         needle[m] = 'B';
117         needle[m + 1] = '\0';
118 
119         result = c_strstr (haystack, needle);
120         ASSERT (result == haystack + m);
121       }
122     free (needle);
123     free (haystack);
124   }
125 
126   {
127     /* Ensure that with a barely periodic "short" needle, c_strstr's
128        search does not mistakenly skip just past the match point.
129        This use of c_strstr would mistakenly return NULL before
130        gnulib v0.0-4927.  */
131     const char *haystack =
132       "\n"
133       "with_build_libsubdir\n"
134       "with_local_prefix\n"
135       "with_gxx_include_dir\n"
136       "with_cpp_install_dir\n"
137       "enable_generated_files_in_srcdir\n"
138       "with_gnu_ld\n"
139       "with_ld\n"
140       "with_demangler_in_ld\n"
141       "with_gnu_as\n"
142       "with_as\n"
143       "enable_largefile\n"
144       "enable_werror_always\n"
145       "enable_checking\n"
146       "enable_coverage\n"
147       "enable_gather_detailed_mem_stats\n"
148       "enable_build_with_cxx\n"
149       "with_stabs\n"
150       "enable_multilib\n"
151       "enable___cxa_atexit\n"
152       "enable_decimal_float\n"
153       "enable_fixed_point\n"
154       "enable_threads\n"
155       "enable_tls\n"
156       "enable_objc_gc\n"
157       "with_dwarf2\n"
158       "enable_shared\n"
159       "with_build_sysroot\n"
160       "with_sysroot\n"
161       "with_specs\n"
162       "with_pkgversion\n"
163       "with_bugurl\n"
164       "enable_languages\n"
165       "with_multilib_list\n";
166     const char *needle = "\n"
167       "with_gnu_ld\n";
168     const char* p = c_strstr (haystack, needle);
169     ASSERT (p - haystack == 114);
170   }
171 
172   {
173     /* Same bug, shorter trigger.  */
174     const char *haystack = "..wi.d.";
175     const char *needle = ".d.";
176     const char* p = c_strstr (haystack, needle);
177     ASSERT (p - haystack == 4);
178   }
179 
180   {
181     /* Like the above, but trigger the flaw in two_way_long_needle
182        by using a needle of length LONG_NEEDLE_THRESHOLD (32) or greater.
183        Rather than trying to find the right alignment manually, I've
184        arbitrarily chosen the following needle and template for the
185        haystack, and ensure that for each placement of the needle in
186        that haystack, c_strstr finds it.  */
187     const char *needle = "\nwith_gnu_ld-extend-to-len-32-b\n";
188     const char *h =
189       "\n"
190       "with_build_libsubdir\n"
191       "with_local_prefix\n"
192       "with_gxx_include_dir\n"
193       "with_cpp_install_dir\n"
194       "with_e_\n"
195       "..............................\n"
196       "with_FGHIJKLMNOPQRSTUVWXYZ\n"
197       "with_567890123456789\n"
198       "with_multilib_list\n";
199     size_t h_len = strlen (h);
200     char *haystack = malloc (h_len + 1);
201     size_t i;
202     ASSERT (haystack);
203     for (i = 0; i < h_len - strlen (needle); i++)
204       {
205         const char *p;
206         memcpy (haystack, h, h_len + 1);
207         memcpy (haystack + i, needle, strlen (needle) + 1);
208         p = c_strstr (haystack, needle);
209         ASSERT (p);
210         ASSERT (p - haystack == i);
211       }
212     free (haystack);
213   }
214 
215   /* Test long needles.  */
216   {
217     size_t m = 1024;
218     char *haystack = (char *) malloc (2 * m + 1);
219     char *needle = (char *) malloc (m + 1);
220     if (haystack != NULL && needle != NULL)
221       {
222         const char *p;
223         haystack[0] = 'x';
224         memset (haystack + 1, ' ', m - 1);
225         memset (haystack + m, 'x', m);
226         haystack[2 * m] = '\0';
227         memset (needle, 'x', m);
228         needle[m] = '\0';
229         p = c_strstr (haystack, needle);
230         ASSERT (p);
231         ASSERT (p - haystack == m);
232       }
233     free (needle);
234     free (haystack);
235   }
236 
237   return 0;
238 }
239