3 files changed, 21 insertions, 15 deletions
diff --git a/bftw.c b/bftw.c
index 8dd98c9..60bc145 100644
--- a/bftw.c
+++ b/bftw.c
@@ -627,7 +627,10 @@ static int bftw_path_concat(struct bftw_state *state, const char *subpath) {
 
 	state->status = BFTW_CHILD;
 
-	return dstrcatat(&state->path, nameoff, subpath);
+	if (dstresize(&state->path, nameoff) != 0) {
+		return -1;
+	}
+	return dstrcat(&state->path, subpath);
 }
 
 /**
diff --git a/dstring.c b/dstring.c
index 9c65757..5a6d4b3 100644
--- a/dstring.c
+++ b/dstring.c
@@ -75,23 +75,26 @@ int dstresize(char **dstr, size_t length) {
 	return 0;
 }
 
-int dstrcat(char **dest, const char *src) {
-	struct dstring *header = dstrheader(*dest);
-	return dstrcatat(dest, header->length, src);
-}
+static int dstrcat_impl(char **dest, const char *src, size_t srclen) {
+	size_t oldlen = dstrlen(*dest);
+	size_t newlen = oldlen + srclen;
 
-int dstrcatat(char **dest, size_t pos, const char *src) {
-	size_t srclen = strlen(src);
-	size_t destlen = pos + srclen;
-
-	if (dstresize(dest, destlen) != 0) {
+	if (dstresize(dest, newlen) != 0) {
 		return -1;
 	}
 
-	memcpy(*dest + pos, src, srclen);
+	memcpy(*dest + oldlen, src, srclen);
 	return 0;
 }
 
+int dstrcat(char **dest, const char *src) {
+	return dstrcat_impl(dest, src, strlen(src));
+}
+
+int dstrncat(char **dest, const char *src, size_t n) {
+	return dstrcat_impl(dest, src, strnlen(src, n));
+}
+
 void dstrfree(char *dstr) {
 	if (dstr) {
 		free(dstrheader(dstr));
diff --git a/dstring.h b/dstring.h
index 7e46da8..cd867ad 100644
--- a/dstring.h
+++ b/dstring.h
@@ -65,17 +65,17 @@ int dstresize(char **dstr, size_t length);
 int dstrcat(char **dest, const char *src);
 
 /**
- * Append to a dynamic string at a particular offset.
+ * Append to a dynamic string.
  *
  * @param dest
  *         The destination dynamic string.
- * @param pos
- *         The offset at which to append.
  * @param src
  *         The string to append.
+ * @param n
+ *         The maximum number of characters to take from src.
  * @return 0 on success, -1 on failure.
  */
-int dstrcatat(char **dest, size_t pos, const char *src);
+int dstrncat(char **dest, const char *src, size_t n);
 
 /**
  * Free a dynamic string.