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authorDenis Vlasenko2008-06-18 19:49:46 +0000
committerDenis Vlasenko2008-06-18 19:49:46 +0000
commitd5736c560703725d13c88234f03e82693212c265 (patch)
tree422a693a8f584c9512641032d6499082c8703606
parent9cd4c76b50b8fde9e21943bcd520168fa9d57290 (diff)
downloadbusybox-d5736c560703725d13c88234f03e82693212c265.zip
busybox-d5736c560703725d13c88234f03e82693212c265.tar.gz
strrchr: bikeshed painting time!
replace cubic running time implementation with quadratic make embedded test actually readable function old new delta strrstr 42 44 +2
-rw-r--r--libbb/strrstr.c94
1 files changed, 43 insertions, 51 deletions
diff --git a/libbb/strrstr.c b/libbb/strrstr.c
index 126fed7..088d9f4 100644
--- a/libbb/strrstr.c
+++ b/libbb/strrstr.c
@@ -7,73 +7,65 @@
* Licensed under GPLv2 or later, see file License in this tarball for details.
*/
+#ifdef __DO_STRRSTR_TEST
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#else
#include "libbb.h"
+#endif
/*
* 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* strrstr(const char *haystack, const char *needle)
{
char *r = NULL;
-
- do {
+
+ if (!needle[0])
+ return (char*)haystack;
+ while (1) {
char *p = strstr(haystack, needle);
- if (p)
- r = p;
- } while (*haystack++);
- return r;
+ 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");
+ static const struct {
+ const char *h, *n;
+ int pos;
+ } test_array[] = {
+ /* 0123456789 */
+ { "baaabaaab", "aaa", 5 },
+ { "baaabaaaab", "aaa", 6 },
+ { "baaabaab", "aaa", 1 },
+ { "aaa", "aaa", 0 },
+ { "aaa", "a", 2 },
+ { "aaa", "bbb", -1 },
+ { "a", "aaa", -1 },
+ { "aaa", "", 3 },
+ { "", "aaa", -1 },
+ { "", "", 0 },
+ };
- ret |= !(n = ((tmp = strrstr("", "")) != NULL && strcmp(tmp, "") == 0));
- printf("'' vs. '' : %s\n", n ? "PASSED" : "FAILED");
+ int i;
- /*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");*/
+ i = 0;
+ while (i < sizeof(test_array) / sizeof(test_array[0])) {
+ const char *r = strrstr(test_array[i].h, test_array[i].n);
+ printf("'%s' vs. '%s': '%s' - ", test_array[i].h, test_array[i].n, r);
+ if (r == NULL)
+ r = test_array[i].h - 1;
+ printf("%s\n", r == test_array[i].h + test_array[i].pos ? "PASSED" : "FAILED");
+ i++;
+ }
- return ret;
+ return 0;
}
#endif