X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;ds=inline;f=lib%2Fofpbuf.c;h=e9ad400ceaec31520a1217b7fdd5279ddc5954cc;hb=5136ce492c414f377f7be9ae32b259abb9f76580;hp=fd01ea8d0227b5af4e8062ff17ee367feccc4c0d;hpb=5019f688d4e3117960503d57978ff2e0fb3771e0;p=openvswitch

diff --git a/lib/ofpbuf.c b/lib/ofpbuf.c
index fd01ea8d..e9ad400c 100644
--- a/lib/ofpbuf.c
+++ b/lib/ofpbuf.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010 Nicira Networks.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@
 #include <assert.h>
 #include <stdlib.h>
 #include <string.h>
+#include "dynamic-string.h"
 #include "util.h"
 
 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
@@ -116,19 +117,14 @@ 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;
@@ -145,22 +141,38 @@ 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) 
 {
     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);
     }
 }
 
@@ -218,6 +230,17 @@ ofpbuf_push_uninit(struct ofpbuf *b, size_t size)
     return b->data;
 }
 
+/* Prefixes 'size' zeroed bytes to the head end of 'b'.  'b' must have at least
+ * 'size' bytes of headroom.  Returns a pointer to the first byte of the data's
+ * location in the ofpbuf. */
+void *
+ofpbuf_push_zeros(struct ofpbuf *b, size_t size)
+{
+    void *dst = ofpbuf_push_uninit(b, size);
+    memset(dst, 0, size);
+    return dst;
+}
+
 void *
 ofpbuf_push(struct ofpbuf *b, const void *p, size_t size) 
 {
@@ -286,3 +309,18 @@ ofpbuf_try_pull(struct ofpbuf *b, size_t size)
 {
     return b->size >= size ? ofpbuf_pull(b, size) : NULL;
 }
+
+/* Returns a string that describes some of 'b''s metadata plus a hex dump of up
+ * to 'maxbytes' from the start of the buffer. */
+char *
+ofpbuf_to_string(const struct ofpbuf *b, size_t maxbytes)
+{
+    struct ds s;
+
+    ds_init(&s);
+    ds_put_format(&s, "size=%zu, allocated=%zu, head=%zu, tail=%zu\n",
+                  b->size, b->allocated,
+                  ofpbuf_headroom(b), ofpbuf_tailroom(b));
+    ds_put_hex_dump(&s, b->data, MIN(b->size, maxbytes), 0, false);
+    return ds_cstr(&s);
+}