Commit 86219f40689c85ec4418575223f4376beffa45af
2017-11-30T15:40:13
util: introduce `git__prefixncmp` and consolidate implementations Introduce `git_prefixncmp` that will search up to the first `n` characters of a string to see if it is prefixed by another string. This is useful for examining if a non-null terminated character array is prefixed by a particular substring. Consolidate the various implementations of `git__prefixcmp` around a single core implementation and add some test cases to validate its behavior.
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diff --git a/src/util.c b/src/util.c
index 6ae5cda..1760a31 100644
--- a/src/util.c
+++ b/src/util.c
@@ -252,35 +252,47 @@ void git__strtolower(char *str)
git__strntolower(str, strlen(str));
}
-int git__prefixcmp(const char *str, const char *prefix)
+GIT_INLINE(int) prefixcmp(const char *str, size_t str_n, const char *prefix, bool icase)
{
- for (;;) {
- unsigned char p = *(prefix++), s;
+ int s, p;
+
+ while (str_n--) {
+ s = (unsigned char)*str++;
+ p = (unsigned char)*prefix++;
+
+ if (icase) {
+ s = git__tolower(s);
+ p = git__tolower(p);
+ }
+
if (!p)
return 0;
- if ((s = *(str++)) != p)
+
+ if (s != p)
return s - p;
}
+
+ return (0 - *prefix);
}
-int git__prefixcmp_icase(const char *str, const char *prefix)
+int git__prefixcmp(const char *str, const char *prefix)
{
- return strncasecmp(str, prefix, strlen(prefix));
+ return prefixcmp(str, SIZE_MAX, prefix, false);
}
-int git__prefixncmp_icase(const char *str, size_t str_n, const char *prefix)
+int git__prefixncmp(const char *str, size_t str_n, const char *prefix)
{
- int s, p;
-
- while(str_n--) {
- s = (unsigned char)git__tolower(*str++);
- p = (unsigned char)git__tolower(*prefix++);
+ return prefixcmp(str, str_n, prefix, false);
+}
- if (s != p)
- return s - p;
- }
+int git__prefixcmp_icase(const char *str, const char *prefix)
+{
+ return prefixcmp(str, SIZE_MAX, prefix, true);
+}
- return (0 - *prefix);
+int git__prefixncmp_icase(const char *str, size_t str_n, const char *prefix)
+{
+ return prefixcmp(str, str_n, prefix, true);
}
int git__suffixcmp(const char *str, const char *suffix)
diff --git a/src/util.h b/src/util.h
index 7c9a54f..80ee8e6 100644
--- a/src/util.h
+++ b/src/util.h
@@ -180,6 +180,7 @@ GIT_INLINE(void) git__free(void *ptr)
extern int git__prefixcmp(const char *str, const char *prefix);
extern int git__prefixcmp_icase(const char *str, const char *prefix);
+extern int git__prefixncmp(const char *str, size_t str_n, const char *prefix);
extern int git__prefixncmp_icase(const char *str, size_t str_n, const char *prefix);
extern int git__suffixcmp(const char *str, const char *suffix);
diff --git a/tests/core/string.c b/tests/core/string.c
index 90e8fa0..85db0c6 100644
--- a/tests/core/string.c
+++ b/tests/core/string.c
@@ -40,6 +40,48 @@ void test_core_string__2(void)
cl_assert(git__strcasesort_cmp("fooBar", "foobar") < 0);
}
+/* compare prefixes with len */
+void test_core_string__prefixncmp(void)
+{
+ cl_assert(git__prefixncmp("", 0, "") == 0);
+ cl_assert(git__prefixncmp("a", 1, "") == 0);
+ cl_assert(git__prefixncmp("", 0, "a") < 0);
+ cl_assert(git__prefixncmp("a", 1, "b") < 0);
+ cl_assert(git__prefixncmp("b", 1, "a") > 0);
+ cl_assert(git__prefixncmp("ab", 2, "a") == 0);
+ cl_assert(git__prefixncmp("ab", 1, "a") == 0);
+ cl_assert(git__prefixncmp("ab", 2, "ac") < 0);
+ cl_assert(git__prefixncmp("a", 1, "ac") < 0);
+ cl_assert(git__prefixncmp("ab", 1, "ac") < 0);
+ cl_assert(git__prefixncmp("ab", 2, "aa") > 0);
+ cl_assert(git__prefixncmp("ab", 1, "aa") < 0);
+}
+
+/* compare prefixes with len */
+void test_core_string__prefixncmp_icase(void)
+{
+ cl_assert(git__prefixncmp_icase("", 0, "") == 0);
+ cl_assert(git__prefixncmp_icase("a", 1, "") == 0);
+ cl_assert(git__prefixncmp_icase("", 0, "a") < 0);
+ cl_assert(git__prefixncmp_icase("a", 1, "b") < 0);
+ cl_assert(git__prefixncmp_icase("A", 1, "b") < 0);
+ cl_assert(git__prefixncmp_icase("a", 1, "B") < 0);
+ cl_assert(git__prefixncmp_icase("b", 1, "a") > 0);
+ cl_assert(git__prefixncmp_icase("B", 1, "a") > 0);
+ cl_assert(git__prefixncmp_icase("b", 1, "A") > 0);
+ cl_assert(git__prefixncmp_icase("ab", 2, "a") == 0);
+ cl_assert(git__prefixncmp_icase("Ab", 2, "a") == 0);
+ cl_assert(git__prefixncmp_icase("ab", 2, "A") == 0);
+ cl_assert(git__prefixncmp_icase("ab", 1, "a") == 0);
+ cl_assert(git__prefixncmp_icase("ab", 2, "ac") < 0);
+ cl_assert(git__prefixncmp_icase("Ab", 2, "ac") < 0);
+ cl_assert(git__prefixncmp_icase("ab", 2, "Ac") < 0);
+ cl_assert(git__prefixncmp_icase("a", 1, "ac") < 0);
+ cl_assert(git__prefixncmp_icase("ab", 1, "ac") < 0);
+ cl_assert(git__prefixncmp_icase("ab", 2, "aa") > 0);
+ cl_assert(git__prefixncmp_icase("ab", 1, "aa") < 0);
+}
+
void test_core_string__strcmp(void)
{
cl_assert(git__strcmp("", "") == 0);