buffer: add functions to prepend data to an existing buffer

2 files changed, 16 insertions, 0 deletions

diff --git a/buffer.c b/buffer.c
index 7784785..3cdf65a 100644
--- a/buffer.c
+++ b/buffer.c
@@ -62,3 +62,16 @@ bool buffer_append0(Buffer *buf, const char *data) {
 		buf->len--;
 	return buffer_append(buf, data, strlen(data)) && buffer_append(buf, "\0", 1);
 }
+
+bool buffer_prepend(Buffer *buf, const void *data, size_t len) {
+	if (!buffer_grow(buf, buf->len + len))
+		return false;
+	memmove(buf->data + len, buf->data, buf->len);
+	memcpy(buf->data, data, len);
+	buf->len += len;
+	return true;
+}
+
+bool buffer_prepend0(Buffer *buf, const char *data) {
+	return buffer_prepend(buf, data, strlen(data) + (buf->len == 0));
+}
diff --git a/buffer.h b/buffer.h
index 088248b..85679c8 100644
--- a/buffer.h
+++ b/buffer.h
@@ -28,4 +28,7 @@ bool buffer_append(Buffer*, const void *data, size_t len);
 /* append NUl-terminated data */
 bool buffer_append0(Buffer*, const char *data);
 
+bool buffer_prepend(Buffer*, const void *data, size_t len);
+bool buffer_prepend0(Buffer*, const char *data);
+
 #endif