LXR 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 tarball for details.
   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 */
  22char* 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
  38int 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
  72