- improved strrstr impl from vda with testcases from Tito and vda

1 files changed, 69 insertions, 6 deletions

diff --git a/libbb/strrstr.c b/libbb/strrstr.c
index b314264f5..3cd76670a 100644
--- a/libbb/strrstr.c
+++ b/libbb/strrstr.c
@@ -7,14 +7,77 @@
  * Licensed under GPLv2 or later, see file License in this tarball for details.
  */
 
-#include "libbb.h"
+#include <string.h>
+#include <stdio.h>
 
-/* reverse strstr() */
+/*
+ * The strrstr() function finds the last occurrence of the substring needle
+ * in the string haystack. The terminating nul characters are not compared.
+ */
 char* strrstr(const char *haystack, const char *needle)
 {
-        char *tmp = strrchr(haystack, *needle);
-        if (tmp == NULL || strcmp(tmp, needle) != 0)
-                return NULL;
-        return tmp;
+        char *r = NULL;
+
+        if (!needle[0])
+                        return r;
+        while (1) {
+                        char *p = strstr(haystack, needle);
+                        if (!p)
+                                        return r;
+                        r = p;
+                        haystack = p + 1;
+        }
 }
 
+#ifdef __DO_STRRSTR_TEST
+/* Test */
+int main(int argc, char **argv)
+{
+        int ret = 0;
+        int n;
+        char *tmp;
+
+        ret |= !(n = ((tmp = strrstr("baaabaaab", "aaa")) != NULL && strcmp(tmp, "aaab") == 0));
+        printf("'baaabaaab'  vs. 'aaa'       : %s\n", n ? "PASSED" : "FAILED");
+
+        ret |= !(n = ((tmp = strrstr("baaabaaaab", "aaa")) != NULL && strcmp(tmp, "aaab") == 0));
+        printf("'baaabaaaab' vs. 'aaa'       : %s\n", n ? "PASSED" : "FAILED");
+
+        ret |= !(n = ((tmp = strrstr("baaabaab", "aaa")) != NULL && strcmp(tmp, "aaabaab") == 0));
+        printf("'baaabaab'   vs. 'aaa'       : %s\n", n ? "PASSED" : "FAILED");
+
+        ret |= !(n = (strrstr("aaa", "aaa") != NULL));
+        printf("'aaa'        vs. 'aaa'       : %s\n", n ? "PASSED" : "FAILED");
+
+        ret |= !(n = (strrstr("aaa", "a") != NULL));
+        printf("'aaa'        vs. 'a'         : %s\n", n ? "PASSED" : "FAILED");
+
+        ret |= !(n = (strrstr("aaa", "bbb") == NULL));
+        printf("'aaa'        vs. 'bbb'       : %s\n", n ? "PASSED" : "FAILED");
+
+        ret |= !(n = (strrstr("a", "aaa") == NULL));
+        printf("'a'          vs. 'aaa'       : %s\n", n ? "PASSED" : "FAILED");
+
+        ret |= !(n = ((tmp = strrstr("aaa", "")) != NULL && strcmp(tmp, "aaa") == 0));
+        printf("'aaa'        vs. ''          : %s\n", n ? "FAILED" : "PASSED");
+
+        ret |= !(n = (strrstr("", "aaa") == NULL));
+        printf("''           vs. 'aaa'       : %s\n", n ? "PASSED" : "FAILED");
+
+        ret |= !(n = ((tmp = strrstr("", "")) != NULL && strcmp(tmp, "") == 0));
+        printf("''           vs. ''          : %s\n", n ? "PASSED" : "FAILED");
+
+        /*ret |= !(n = (strrstr(NULL, NULL) == NULL));
+        printf("'NULL'       vs. 'NULL'      : %s\n", n ? "PASSED" : "FAILED");
+        ret |= !(n = (strrstr("", NULL) == NULL));
+        printf("''           vs. 'NULL'      : %s\n", n ? "PASSED" : "FAILED");
+        ret |= !(n = (strrstr(NULL, "") == NULL));
+        printf("'NULL'       vs. ''          : %s\n", n ? "PASSED" : "FAILED");
+        ret |= !(n = (strrstr("aaa", NULL) == NULL));
+        printf("'aaa'        vs. 'NULL'      : %s\n", n ? "PASSED" : "FAILED");
+        ret |= !(n = (strrstr(NULL, "aaa") == NULL));
+        printf("'NULL'       vs. 'aaa'       : %s\n", n ? "PASSED" : "FAILED");*/
+
+        return ret;
+}
+#endif