release/src/router/busybox/libbb/strrstr.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Utility routines.
   4  *
   5  * Copyright (C) 2008 Bernhard Reutner-Fischer
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8  */
   9
  10 #ifdef __DO_STRRSTR_TEST
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <stdio.h>
  14 #else
  15 #include "libbb.h"
  16 #endif
  17
  18 /*
  19  * The strrstr() function finds the last occurrence of the substring needle
  20  * in the string haystack. The terminating nul characters are not compared.
  21  */
  22 char* FAST_FUNC strrstr(const char *haystack, const char *needle)
  23 {
  24         char *r = NULL;
  25
  26         if (!needle[0])
  27                 return (char*)haystack + strlen(haystack);
  28         while (1) {
  29                 char *p = strstr(haystack, needle);
  30                 if (!p)
  31                         return r;
  32                 r = p;
  33                 haystack = p + 1;
  34         }
  35 }
  36
  37 #ifdef __DO_STRRSTR_TEST
  38 int main(int argc, char **argv)
  39 {
  40         static const struct {
  41                 const char *h, *n;
  42                 int pos;
  43         } test_array[] = {
  44                 /* 0123456789 */
  45                 { "baaabaaab",  "aaa", 5  },
  46                 { "baaabaaaab", "aaa", 6  },
  47                 { "baaabaab",   "aaa", 1  },
  48                 { "aaa",        "aaa", 0  },
  49                 { "aaa",        "a",   2  },
  50                 { "aaa",        "bbb", -1 },
  51                 { "a",          "aaa", -1 },
  52                 { "aaa",        "",    3  },
  53                 { "",           "aaa", -1 },
  54                 { "",           "",    0  },
  55         };
  56
  57         int i;
  58
  59         i = 0;
  60         while (i < sizeof(test_array) / sizeof(test_array[0])) {
  61                 const char *r = strrstr(test_array[i].h, test_array[i].n);
  62                 printf("'%s' vs. '%s': '%s' - ", test_array[i].h, test_array[i].n, r);
  63                 if (r == NULL)
  64                         r = test_array[i].h - 1;
  65                 printf("%s\n", r == test_array[i].h + test_array[i].pos ? "PASSED" : "FAILED");
  66                 i++;
  67         }
  68
  69         return 0;
  70 }
  71 #endif