/*
- * 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.
#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
* commonly, the data in a ofpbuf is at its beginning, and thus the ofpbuf's
* headroom is 0.) */
size_t
-ofpbuf_headroom(struct ofpbuf *b)
+ofpbuf_headroom(const struct ofpbuf *b)
{
return (char*)b->data - (char*)b->base;
}
/* Returns the number of bytes that may be appended to the tail end of ofpbuf
* 'b' before the ofpbuf must be reallocated. */
size_t
-ofpbuf_tailroom(struct ofpbuf *b)
+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;
}
}
+/* 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);
}
}
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)
{
{
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);
+}