/*
- * Copyright (c) 2008, 2009, 2010 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
/* 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
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;
}
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)
{
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;
}
return (char*)ofpbuf_end(b) - (char*)ofpbuf_tail(b);
}
-/* 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)
+ofpbuf_copy__(struct ofpbuf *b, uint8_t *new_base,
+ size_t new_headroom, size_t new_tailroom)
{
- if (b->base != new_base) {
- uintptr_t base_delta = (char*)new_base - (char*)b->base;
- b->base = new_base;
- b->data = (char*)b->data + base_delta;
- if (b->l2) {
- b->l2 = (char*)b->l2 + base_delta;
- }
- if (b->l3) {
- b->l3 = (char*)b->l3 + base_delta;
- }
- if (b->l4) {
- b->l4 = (char*)b->l4 + base_delta;
- }
- if (b->l7) {
- b->l7 = (char*)b->l7 + base_delta;
- }
- }
+ const uint8_t *old_base = b->base;
+ size_t old_headroom = ofpbuf_headroom(b);
+ size_t old_tailroom = ofpbuf_tailroom(b);
+ size_t copy_headroom = MIN(old_headroom, new_headroom);
+ size_t copy_tailroom = MIN(old_tailroom, new_tailroom);
+
+ memcpy(&new_base[new_headroom - copy_headroom],
+ &old_base[old_headroom - copy_headroom],
+ copy_headroom + b->size + copy_tailroom);
}
-/* Reallocates 'b' so that it has exactly 'new_tailroom' bytes of tailroom. */
+/* Reallocates 'b' so that it has exactly 'new_headroom' and 'new_tailroom'
+ * bytes of headroom and tailroom, respectively. */
static void
-ofpbuf_resize_tailroom__(struct ofpbuf *b, size_t new_tailroom)
+ofpbuf_resize__(struct ofpbuf *b, size_t new_headroom, size_t new_tailroom)
{
+ void *new_base, *new_data;
size_t new_allocated;
- void *new_base;
- new_allocated = ofpbuf_headroom(b) + b->size + new_tailroom;
+ new_allocated = new_headroom + b->size + new_tailroom;
switch (b->source) {
case OFPBUF_MALLOC:
- new_base = xrealloc(b->base, new_allocated);
+ if (new_headroom == ofpbuf_headroom(b)) {
+ new_base = xrealloc(b->base, new_allocated);
+ } else {
+ new_base = xmalloc(new_allocated);
+ ofpbuf_copy__(b, new_base, new_headroom, new_tailroom);
+ free(b->base);
+ }
break;
case OFPBUF_STACK:
- new_base = xmalloc(new_allocated);
- memcpy(new_base, b->base, MIN(new_allocated, b->allocated));
- b->source = OFPBUF_MALLOC;
- break;
-
- case OFPBUF_CONST:
NOT_REACHED();
default:
}
b->allocated = new_allocated;
- ofpbuf_rebase__(b, new_base);
+ b->base = new_base;
+
+ new_data = (char *) new_base + new_headroom;
+ if (b->data != new_data) {
+ uintptr_t data_delta = (char *) new_data - (char *) b->data;
+ b->data = new_data;
+ if (b->l2) {
+ b->l2 = (char *) b->l2 + data_delta;
+ }
+ if (b->l3) {
+ b->l3 = (char *) b->l3 + data_delta;
+ }
+ if (b->l4) {
+ b->l4 = (char *) b->l4 + data_delta;
+ }
+ if (b->l7) {
+ b->l7 = (char *) b->l7 + data_delta;
+ }
+ }
}
/* Ensures that 'b' has room for at least 'size' bytes at its tail end,
ofpbuf_prealloc_tailroom(struct ofpbuf *b, size_t size)
{
if (size > ofpbuf_tailroom(b)) {
- ofpbuf_resize_tailroom__(b, MAX(size, 64));
+ ofpbuf_resize__(b, ofpbuf_headroom(b), MAX(size, 64));
}
}
+/* Ensures that 'b' has room for at least 'size' bytes at its head,
+ * reallocating and copying its data if necessary. Its tailroom, if any, is
+ * preserved. */
void
ofpbuf_prealloc_headroom(struct ofpbuf *b, size_t size)
{
- assert(size <= ofpbuf_headroom(b));
+ if (size > ofpbuf_headroom(b)) {
+ ofpbuf_resize__(b, MAX(size, 64), ofpbuf_tailroom(b));
+ }
}
/* Trims the size of 'b' to fit its actual content, reducing its tailroom to
void
ofpbuf_trim(struct ofpbuf *b)
{
- if (b->source == OFPBUF_MALLOC && ofpbuf_tailroom(b) > 0) {
- ofpbuf_resize_tailroom__(b, 0);
+ if (b->source == OFPBUF_MALLOC
+ && (ofpbuf_headroom(b) || ofpbuf_tailroom(b))) {
+ ofpbuf_resize__(b, 0, 0);
}
}
b->data = (char*)b->data + size;
}
+/* Prefixes 'size' bytes to the head end of 'b', reallocating and copying its
+ * data if necessary. Returns a pointer to the first byte of the data's
+ * location in the ofpbuf. The new data is left uninitialized. */
void *
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. */
+/* Prefixes 'size' zeroed bytes to the head end of 'b', reallocating and
+ * copying its data if necessary. 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)
{
return dst;
}
+/* Copies the 'size' bytes starting at 'p' to the head end of 'b', reallocating
+ * and copying its data if necessary. Returns a pointer to the first byte of
+ * the data's location in the ofpbuf. */
void *
ofpbuf_push(struct ofpbuf *b, const void *p, size_t size)
{
return b->size >= size ? ofpbuf_pull(b, size) : NULL;
}
+/* Returns the data in 'b' as a block of malloc()'d memory and frees the buffer
+ * within 'b'. (If 'b' itself was dynamically allocated, e.g. with
+ * ofpbuf_new(), then it should still be freed with, e.g., ofpbuf_delete().) */
+void *
+ofpbuf_steal_data(struct ofpbuf *b)
+{
+ void *p;
+ if (b->source == OFPBUF_MALLOC && b->data == b->base) {
+ p = b->data;
+ } else {
+ p = xmemdup(b->data, b->size);
+ if (b->source == OFPBUF_MALLOC) {
+ free(b->base);
+ }
+ }
+ b->base = b->data = NULL;
+ return p;
+}
+
/* 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 *
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