1 files changed, 24 insertions, 0 deletions
diff --git a/src/lib/string.c b/src/lib/string.c
index 05549e0..db08b28 100644
--- a/src/lib/string.c
+++ b/src/lib/string.c
@@ -168,3 +168,27 @@ string_compare(struct string *a, struct string *b)
 	else
 		return 0;
 }
+
+struct string *
+substring(struct aplwc *aplwc, struct string *s, size_t start, size_t length)
+{
+	size_t bytes, i;
+	struct string *r;
+
+	MEMPTRS(aplwc, 1);
+	MEMPTR(0, s);
+
+	bytes = 0;
+	for(i = 0; i < length; i++)
+		bytes += char_length(s, start+i);
+
+	r = memory_alloc_string(aplwc, bytes);
+	if(r){
+		r->bytes = bytes;
+		r->chars = length;
+		memcpy(r->utf8, s->utf8+start, bytes);
+	}
+
+	MEMPTRS_EXIT(aplwc);
+	return r;
+}