string_list: add two new functions for splitting strings

Add two new functions, string_list_split() and
string_list_split_in_place().  These split a string into a string_list
on a separator character.  The first makes copies of the substrings
(leaving the input string untouched) and the second splits the
original string in place, overwriting the separator characters with
NULs and referring to the original string's memory.

These functions are similar to the strbuf_split_*() functions except
that they work with the more powerful string_list interface.

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

1 files changed, 53 insertions, 0 deletions

diff --git a/string-list.c b/string-list.c
index ad2aa5af91..acb1f5b6dc 100644
--- a/string-list.c
+++ b/string-list.c
@@ -204,3 +204,56 @@ void unsorted_string_list_delete_item(struct string_list *list, int i, int free_
 	list->items[i] = list->items[list->nr-1];
 	list->nr--;
 }
+
+int string_list_split(struct string_list *list, const char *string,
+		      int delim, int maxsplit)
+{
+	int count = 0;
+	const char *p = string, *end;
+
+	if (!list->strdup_strings)
+		die("internal error in string_list_split(): "
+		    "list->strdup_strings must be set");
+	for (;;) {
+		count++;
+		if (maxsplit >= 0 && count > maxsplit) {
+			string_list_append(list, p);
+			return count;
+		}
+		end = strchr(p, delim);
+		if (end) {
+			string_list_append_nodup(list, xmemdupz(p, end - p));
+			p = end + 1;
+		} else {
+			string_list_append(list, p);
+			return count;
+		}
+	}
+}
+
+int string_list_split_in_place(struct string_list *list, char *string,
+			       int delim, int maxsplit)
+{
+	int count = 0;
+	char *p = string, *end;
+
+	if (list->strdup_strings)
+		die("internal error in string_list_split_in_place(): "
+		    "list->strdup_strings must not be set");
+	for (;;) {
+		count++;
+		if (maxsplit >= 0 && count > maxsplit) {
+			string_list_append(list, p);
+			return count;
+		}
+		end = strchr(p, delim);
+		if (end) {
+			*end = '\0';
+			string_list_append(list, p);
+			p = end + 1;
+		} else {
+			string_list_append(list, p);
+			return count;
+		}
+	}
+}