X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Fofpbuf.c;h=29698dcd83beefdedb2ba985f4305e63a9eaa4d9;hb=541bc79f73add327072470c9bc3febb4195cdb3c;hp=7e9653600c2c881bbc67e657fe08fb6ac494733a;hpb=933369b1194bce82bffa8cc1ccfdf82782cc5cde;p=openvswitch

diff --git a/lib/ofpbuf.c b/lib/ofpbuf.c
index 7e965360..29698dcd 100644
--- a/lib/ofpbuf.c
+++ b/lib/ofpbuf.c
@@ -47,9 +47,9 @@ ofpbuf_use(struct ofpbuf *b, void *base, size_t allocated)
 
 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
  * memory starting at 'base'.  'base' should point to a buffer on the stack.
- * If 'b' is resized, new memory will be allocated with malloc() and 'base'
- * will not be freed.  This is useful when a small stack-allocated buffer is
- * normally appropriate but sometimes it must be expanded.
+ *
+ * An ofpbuf operation that requires reallocating data will assert-fail if this
+ * function was used to initialize it.
  *
  * 'base' should be appropriately aligned.  Using an array of uint32_t or
  * uint64_t for the buffer is a reasonable way to ensure appropriate alignment
@@ -74,7 +74,7 @@ ofpbuf_use_stack(struct ofpbuf *b, void *base, size_t allocated)
 void
 ofpbuf_use_const(struct ofpbuf *b, const void *data, size_t size)
 {
-    ofpbuf_use__(b, (void *) data, size, OFPBUF_CONST);
+    ofpbuf_use__(b, (void *) data, size, OFPBUF_STACK);
     b->size = size;
 }
 
@@ -129,7 +129,7 @@ ofpbuf_new_with_headroom(size_t size, size_t headroom)
 struct ofpbuf *
 ofpbuf_clone(const struct ofpbuf *buffer)
 {
-    return ofpbuf_clone_data(buffer->data, buffer->size);
+    return ofpbuf_clone_with_headroom(buffer, 0);
 }
 
 /* Creates and returns a new ofpbuf whose data are copied from 'buffer'.   The
@@ -137,8 +137,27 @@ ofpbuf_clone(const struct ofpbuf *buffer)
 struct ofpbuf *
 ofpbuf_clone_with_headroom(const struct ofpbuf *buffer, size_t headroom)
 {
-    return ofpbuf_clone_data_with_headroom(buffer->data, buffer->size,
-                                           headroom);
+    struct ofpbuf *new_buffer;
+    uintptr_t data_delta;
+
+    new_buffer = ofpbuf_clone_data_with_headroom(buffer->data, buffer->size,
+                                                 headroom);
+    data_delta = (char *) new_buffer->data - (char *) buffer->data;
+
+    if (buffer->l2) {
+        new_buffer->l2 = (char *) buffer->l2 + data_delta;
+    }
+    if (buffer->l3) {
+        new_buffer->l3 = (char *) buffer->l3 + data_delta;
+    }
+    if (buffer->l4) {
+        new_buffer->l4 = (char *) buffer->l4 + data_delta;
+    }
+    if (buffer->l7) {
+        new_buffer->l7 = (char *) buffer->l7 + data_delta;
+    }
+
+    return new_buffer;
 }
 
 /* Creates and returns a new ofpbuf that initially contains a copy of the
@@ -225,12 +244,6 @@ ofpbuf_resize__(struct ofpbuf *b, size_t new_headroom, size_t new_tailroom)
         break;
 
     case OFPBUF_STACK:
-        new_base = xmalloc(new_allocated);
-        ofpbuf_copy__(b, new_base, new_headroom, new_tailroom);
-        b->source = OFPBUF_MALLOC;
-        break;
-
-    case OFPBUF_CONST:
         NOT_REACHED();
 
     default:
@@ -295,6 +308,16 @@ ofpbuf_trim(struct ofpbuf *b)
     }
 }
 
+/* If 'b' is shorter than 'length' bytes, pads its tail out with zeros to that
+ * length. */
+void
+ofpbuf_padto(struct ofpbuf *b, size_t length)
+{
+    if (b->size < length) {
+        ofpbuf_put_zeros(b, length - b->size);
+    }
+}
+
 /* Appends 'size' bytes of data to the tail end of 'b', reallocating and
  * copying its data if necessary.  Returns a pointer to the first byte of the
  * new data, which is left uninitialized. */