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 source tree.
   8 */
   9#include "libbb.h"
  10
  11/*
  12 * The strrstr() function finds the last occurrence of the substring needle
  13 * in the string haystack. The terminating nul characters are not compared.
  14 */
  15char* FAST_FUNC strrstr(const char *haystack, const char *needle)
  16{
  17        char *r = NULL;
  18
  19        if (!needle[0])
  20                return (char*)haystack + strlen(haystack);
  21        while (1) {
  22                char *p = strstr(haystack, needle);
  23                if (!p)
  24                        return r;
  25                r = p;
  26                haystack = p + 1;
  27        }
  28}
  29
  30#if ENABLE_UNIT_TEST
  31
  32BBUNIT_DEFINE_TEST(strrstr)
  33{
  34        static const struct {
  35                const char *h, *n;
  36                int pos;
  37        } test_array[] = {
  38                /* 0123456789 */
  39                { "baaabaaab",  "aaa", 5  },
  40                { "baaabaaaab", "aaa", 6  },
  41                { "baaabaab",   "aaa", 1  },
  42                { "aaa",        "aaa", 0  },
  43                { "aaa",        "a",   2  },
  44                { "aaa",        "bbb", -1 },
  45                { "a",          "aaa", -1 },
  46                { "aaa",        "",    3  },
  47                { "",           "aaa", -1 },
  48                { "",           "",    0  },
  49        };
  50
  51        int i;
  52
  53        i = 0;
  54        while (i < sizeof(test_array) / sizeof(test_array[0])) {
  55                const char *r = strrstr(test_array[i].h, test_array[i].n);
  56                if (r == NULL)
  57                        r = test_array[i].h - 1;
  58                BBUNIT_ASSERT_EQ(r, test_array[i].h + test_array[i].pos);
  59                i++;
  60        }
  61
  62        BBUNIT_ENDTEST;
  63}
  64
  65#endif /* ENABLE_UNIT_TEST */
  66