X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fofpbuf.c;h=bf5567251066a12bb7f05e9c45339617b48e5fe3;hb=06036898849974797cf49c76a56fc6e10461d37d;hp=1621bcc198128e9140323a32891ab9d99e9cef82;hpb=30f07f1a5e2a021d8e05167b5db93968a2036033;p=sliver-openvswitch.git

diff --git a/lib/ofpbuf.c b/lib/ofpbuf.c
index 1621bcc19..bf5567251 100644
--- a/lib/ofpbuf.c
+++ b/lib/ofpbuf.c
@@ -50,7 +50,7 @@ ofpbuf_init(struct ofpbuf *b, size_t size)
 
 /* Frees memory that 'b' points to. */
 void
-ofpbuf_uninit(struct ofpbuf *b) 
+ofpbuf_uninit(struct ofpbuf *b)
 {
     if (b) {
         free(b->base);
@@ -75,12 +75,32 @@ ofpbuf_new(size_t size)
     return b;
 }
 
+/* Creates and returns a new ofpbuf with an initial capacity of 'size +
+ * headroom' bytes, reserving the first 'headroom' bytes as headroom. */
+struct ofpbuf *
+ofpbuf_new_with_headroom(size_t size, size_t headroom)
+{
+    struct ofpbuf *b = ofpbuf_new(size + headroom);
+    ofpbuf_reserve(b, headroom);
+    return b;
+}
+
 struct ofpbuf *
 ofpbuf_clone(const struct ofpbuf *buffer)
 {
     return ofpbuf_clone_data(buffer->data, buffer->size);
 }
 
+/* Creates and returns a new ofpbuf whose data are copied from 'buffer'.   The
+ * returned ofpbuf will additionally have 'headroom' bytes of headroom. */
+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;
+}
+
 struct ofpbuf *
 ofpbuf_clone_data(const void *data, size_t size)
 {
@@ -91,7 +111,7 @@ ofpbuf_clone_data(const void *data, size_t size)
 
 /* Frees memory that 'b' points to, as well as 'b' itself. */
 void
-ofpbuf_delete(struct ofpbuf *b) 
+ofpbuf_delete(struct ofpbuf *b)
 {
     if (b) {
         ofpbuf_uninit(b);
@@ -117,19 +137,14 @@ ofpbuf_tailroom(const struct ofpbuf *b)
     return (char*)ofpbuf_end(b) - (char*)ofpbuf_tail(b);
 }
 
-/* Ensures that 'b' has room for at least 'size' bytes at its tail end,
- * reallocating and copying its data if necessary. */
-void
-ofpbuf_prealloc_tailroom(struct ofpbuf *b, size_t size) 
+/* Changes 'b->base' to 'new_base' and adjusts all of 'b''s internal pointers
+ * to reflect the change. */
+static void
+ofpbuf_rebase__(struct ofpbuf *b, void *new_base)
 {
-    if (size > ofpbuf_tailroom(b)) {
-        size_t new_allocated = b->allocated + MAX(size, 64);
-        void *new_base = xmalloc(new_allocated);
+    if (b->base != new_base) {
         uintptr_t base_delta = (char*)new_base - (char*)b->base;
-        memcpy(new_base, b->base, b->allocated);
-        free(b->base);
         b->base = new_base;
-        b->allocated = new_allocated;
         b->data = (char*)b->data + base_delta;
         if (b->l2) {
             b->l2 = (char*)b->l2 + base_delta;
@@ -146,22 +161,38 @@ ofpbuf_prealloc_tailroom(struct ofpbuf *b, size_t size)
     }
 }
 
+/* Reallocates 'b' so that it has exactly 'new_tailroom' bytes of tailroom. */
+static void
+ofpbuf_resize_tailroom__(struct ofpbuf *b, size_t new_tailroom)
+{
+    b->allocated = ofpbuf_headroom(b) + b->size + new_tailroom;
+    ofpbuf_rebase__(b, xrealloc(b->base, b->allocated));
+}
+
+/* Ensures that 'b' has room for at least 'size' bytes at its tail end,
+ * reallocating and copying its data if necessary.  Its headroom, if any, is
+ * preserved. */
+void
+ofpbuf_prealloc_tailroom(struct ofpbuf *b, size_t size)
+{
+    if (size > ofpbuf_tailroom(b)) {
+        ofpbuf_resize_tailroom__(b, MAX(size, 64));
+    }
+}
+
 void
-ofpbuf_prealloc_headroom(struct ofpbuf *b, size_t size) 
+ofpbuf_prealloc_headroom(struct ofpbuf *b, size_t size)
 {
     assert(size <= ofpbuf_headroom(b));
 }
 
-/* Trims the size of 'b' to fit its actual content. */
+/* Trims the size of 'b' to fit its actual content, reducing its tailroom to
+ * 0.  Its headroom, if any, is preserved. */
 void
 ofpbuf_trim(struct ofpbuf *b)
 {
-    /* XXX These could be supported, but the current client doesn't care. */
-    assert(b->data == b->base);
-    assert(b->l2 == NULL && b->l3 == NULL && b->l4 == NULL && b->l7 == NULL);
-    if (b->allocated > b->size) {
-        b->base = b->data = xrealloc(b->base, b->size);
-        b->allocated = b->size;
+    if (ofpbuf_tailroom(b) > 0) {
+        ofpbuf_resize_tailroom__(b, 0);
     }
 }
 
@@ -169,7 +200,7 @@ ofpbuf_trim(struct ofpbuf *b)
  * copying its data if necessary.  Returns a pointer to the first byte of the
  * new data, which is left uninitialized. */
 void *
-ofpbuf_put_uninit(struct ofpbuf *b, size_t size) 
+ofpbuf_put_uninit(struct ofpbuf *b, size_t size)
 {
     void *p;
     ofpbuf_prealloc_tailroom(b, size);
@@ -193,7 +224,7 @@ ofpbuf_put_zeros(struct ofpbuf *b, size_t size)
  * is reallocated and copied if necessary.  Returns a pointer to the first
  * byte of the data's location in the ofpbuf. */
 void *
-ofpbuf_put(struct ofpbuf *b, const void *p, size_t size) 
+ofpbuf_put(struct ofpbuf *b, const void *p, size_t size)
 {
     void *dst = ofpbuf_put_uninit(b, size);
     memcpy(dst, p, size);
@@ -203,7 +234,7 @@ ofpbuf_put(struct ofpbuf *b, const void *p, size_t size)
 /* Reserves 'size' bytes of headroom so that they can be later allocated with
  * ofpbuf_push_uninit() without reallocating the ofpbuf. */
 void
-ofpbuf_reserve(struct ofpbuf *b, size_t size) 
+ofpbuf_reserve(struct ofpbuf *b, size_t size)
 {
     assert(!b->size);
     ofpbuf_prealloc_tailroom(b, size);
@@ -211,7 +242,7 @@ ofpbuf_reserve(struct ofpbuf *b, size_t size)
 }
 
 void *
-ofpbuf_push_uninit(struct ofpbuf *b, size_t size) 
+ofpbuf_push_uninit(struct ofpbuf *b, size_t size)
 {
     ofpbuf_prealloc_headroom(b, size);
     b->data = (char*)b->data - size;
@@ -231,7 +262,7 @@ ofpbuf_push_zeros(struct ofpbuf *b, size_t size)
 }
 
 void *
-ofpbuf_push(struct ofpbuf *b, const void *p, size_t size) 
+ofpbuf_push(struct ofpbuf *b, const void *p, size_t size)
 {
     void *dst = ofpbuf_push_uninit(b, size);
     memcpy(dst, p, size);
@@ -241,7 +272,7 @@ ofpbuf_push(struct ofpbuf *b, const void *p, size_t size)
 /* If 'b' contains at least 'offset + size' bytes of data, returns a pointer to
  * byte 'offset'.  Otherwise, returns a null pointer. */
 void *
-ofpbuf_at(const struct ofpbuf *b, size_t offset, size_t size) 
+ofpbuf_at(const struct ofpbuf *b, size_t offset, size_t size)
 {
     return offset + size <= b->size ? (char *) b->data + offset : NULL;
 }
@@ -249,7 +280,7 @@ ofpbuf_at(const struct ofpbuf *b, size_t offset, size_t size)
 /* Returns a pointer to byte 'offset' in 'b', which must contain at least
  * 'offset + size' bytes of data. */
 void *
-ofpbuf_at_assert(const struct ofpbuf *b, size_t offset, size_t size) 
+ofpbuf_at_assert(const struct ofpbuf *b, size_t offset, size_t size)
 {
     assert(offset + size <= b->size);
     return ((char *) b->data) + offset;
@@ -257,7 +288,7 @@ ofpbuf_at_assert(const struct ofpbuf *b, size_t offset, size_t size)
 
 /* Returns the byte following the last byte of data in use in 'b'. */
 void *
-ofpbuf_tail(const struct ofpbuf *b) 
+ofpbuf_tail(const struct ofpbuf *b)
 {
     return (char *) b->data + b->size;
 }
@@ -265,14 +296,14 @@ ofpbuf_tail(const struct ofpbuf *b)
 /* Returns the byte following the last byte allocated for use (but not
  * necessarily in use) by 'b'. */
 void *
-ofpbuf_end(const struct ofpbuf *b) 
+ofpbuf_end(const struct ofpbuf *b)
 {
     return (char *) b->base + b->allocated;
 }
 
 /* Clears any data from 'b'. */
 void
-ofpbuf_clear(struct ofpbuf *b) 
+ofpbuf_clear(struct ofpbuf *b)
 {
     b->data = b->base;
     b->size = 0;
@@ -281,7 +312,7 @@ ofpbuf_clear(struct ofpbuf *b)
 /* Removes 'size' bytes from the head end of 'b', which must contain at least
  * 'size' bytes of data.  Returns the first byte of data removed. */
 void *
-ofpbuf_pull(struct ofpbuf *b, size_t size) 
+ofpbuf_pull(struct ofpbuf *b, size_t size)
 {
     void *data = b->data;
     assert(b->size >= size);
@@ -294,7 +325,7 @@ ofpbuf_pull(struct ofpbuf *b, size_t size)
  * head end of 'b' and returns the first byte removed.  Otherwise, returns a
  * null pointer without modifying 'b'. */
 void *
-ofpbuf_try_pull(struct ofpbuf *b, size_t size) 
+ofpbuf_try_pull(struct ofpbuf *b, size_t size)
 {
     return b->size >= size ? ofpbuf_pull(b, size) : NULL;
 }