dstring: New dstrndup() function

2 files changed, 19 insertions, 1 deletions

diff --git a/dstring.c b/dstring.c
index d7ce456..8b226bc 100644
--- a/dstring.c
+++ b/dstring.c
@@ -49,7 +49,10 @@ static char *dstralloc_impl(size_t capacity, size_t length, const char *data) {
 
 	header->capacity = capacity;
 	header->length = length;
-	return memcpy(header->data, data, length + 1);
+
+	memcpy(header->data, data, length);
+	header->data[length] = '\0';
+	return header->data;
 }
 
 char *dstralloc(size_t capacity) {
@@ -61,6 +64,11 @@ char *dstrdup(const char *str) {
 	return dstralloc_impl(len, len, str);
 }
 
+char *dstrndup(const char *str, size_t n) {
+	size_t len = strnlen(str, n);
+	return dstralloc_impl(len, len, str);
+}
+
 size_t dstrlen(const char *dstr) {
 	return dstrheader(dstr)->length;
 }
diff --git a/dstring.h b/dstring.h
index 22476b9..19fd6d7 100644
--- a/dstring.h
+++ b/dstring.h
@@ -41,6 +41,16 @@ char *dstralloc(size_t capacity);
 char *dstrdup(const char *str);
 
 /**
+ * Create a length-limited dynamic copy of a string.
+ *
+ * @param str
+ *         The string to copy.
+ * @param n
+ *         The maximum number of characters to copy from str.
+ */
+char *dstrndup(const char *str, size_t n);
+
+/**
  * Get a dynamic string's length.
  *
  * @param dstr