string_list: add a function string_list_longest_prefix()

Add a function that finds the longest string from a string_list that
is a prefix of a given string.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/string-list.c b/string-list.c
index decfa747fc..c54b816244 100644
--- a/string-list.c
+++ b/string-list.c
@@ -136,6 +136,26 @@ void filter_string_list(struct string_list *list, int free_util,
 	list->nr = dst;
 }
 
+char *string_list_longest_prefix(const struct string_list *prefixes,
+				 const char *string)
+{
+	int i, max_len = -1;
+	char *retval = NULL;
+
+	for (i = 0; i < prefixes->nr; i++) {
+		char *prefix = prefixes->items[i].string;
+		if (!prefixcmp(string, prefix)) {
+			int len = strlen(prefix);
+			if (len > max_len) {
+				retval = prefix;
+				max_len = len;
+			}
+		}
+	}
+
+	return retval;
+}
+
 void string_list_clear(struct string_list *list, int free_util)
 {
 	if (list->items) {