ofpbuf: New function ofpbuf_clone_data_with_headroom().

This new function is a simple helper that creates a new ofpbuf with some
initial contents plus a caller-specified amount of headroom.

This will be used in upcoming commits.

Acked-by: Jesse Gross <jesse@nicira.com>

diff --git a/lib/ofpbuf.c b/lib/ofpbuf.c
index 8191c87b7ef47b269df227e62ee0473b5f5dfc08..34aad93825126943d4ffbaaaf9be9a8aa2d2b677 100644 (file)
--- a/lib/ofpbuf.c
+++ b/lib/ofpbuf.c
@@ -123,6 +123,9 @@ ofpbuf_new_with_headroom(size_t size, size_t headroom)
     return b;
 }
 
+/* Creates and returns a new ofpbuf that initially contains a copy of the
+ * 'buffer->size' bytes of data starting at 'buffer->data' with no headroom or
+ * tailroom. */
 struct ofpbuf *
 ofpbuf_clone(const struct ofpbuf *buffer)
 {
@@ -134,15 +137,25 @@ ofpbuf_clone(const struct ofpbuf *buffer)
 struct ofpbuf *
 ofpbuf_clone_with_headroom(const struct ofpbuf *buffer, size_t headroom)
 {
-    struct ofpbuf *b = ofpbuf_new_with_headroom(buffer->size, headroom);
-    ofpbuf_put(b, buffer->data, buffer->size);
-    return b;
+    return ofpbuf_clone_data_with_headroom(buffer->data, buffer->size,
+                                           headroom);
 }
 
+/* Creates and returns a new ofpbuf that initially contains a copy of the
+ * 'size' bytes of data starting at 'data' with no headroom or tailroom. */
 struct ofpbuf *
 ofpbuf_clone_data(const void *data, size_t size)
 {
-    struct ofpbuf *b = ofpbuf_new(size);
+    return ofpbuf_clone_data_with_headroom(data, size, 0);
+}
+
+/* Creates and returns a new ofpbuf that initially contains 'headroom' bytes of
+ * headroom followed by a copy of the 'size' bytes of data starting at
+ * 'data'. */
+struct ofpbuf *
+ofpbuf_clone_data_with_headroom(const void *data, size_t size, size_t headroom)
+{
+    struct ofpbuf *b = ofpbuf_new_with_headroom(size, headroom);
     ofpbuf_put(b, data, size);
     return b;
 }

diff --git a/lib/ofpbuf.h b/lib/ofpbuf.h
index 15f0ab1626e2ee56935628aadd034358c8fd19f0..442c90c9134f1224625bbeed7a7aa58ccdc4feef 100644 (file)
--- a/lib/ofpbuf.h
+++ b/lib/ofpbuf.h
@@ -69,6 +69,8 @@ struct ofpbuf *ofpbuf_clone(const struct ofpbuf *);
 struct ofpbuf *ofpbuf_clone_with_headroom(const struct ofpbuf *,
                                           size_t headroom);
 struct ofpbuf *ofpbuf_clone_data(const void *, size_t);
+struct ofpbuf *ofpbuf_clone_data_with_headroom(const void *, size_t,
+                                               size_t headroom);
 void ofpbuf_delete(struct ofpbuf *);
 
 void *ofpbuf_at(const struct ofpbuf *, size_t offset, size_t size);