2 * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
21 #include "dynamic-string.h"
25 ofpbuf_use__(struct ofpbuf *b, void *base, size_t allocated,
26 enum ofpbuf_source source)
28 b->base = b->data = base;
29 b->allocated = allocated;
32 b->l2 = b->l3 = b->l4 = b->l7 = NULL;
33 list_poison(&b->list_node);
37 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
38 * memory starting at 'base'. 'base' should be the first byte of a region
39 * obtained from malloc(). It will be freed (with free()) if 'b' is resized or
42 ofpbuf_use(struct ofpbuf *b, void *base, size_t allocated)
44 ofpbuf_use__(b, base, allocated, OFPBUF_MALLOC);
47 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
48 * memory starting at 'base'. 'base' should point to a buffer on the stack.
49 * (Nothing actually relies on 'base' being allocated on the stack. It could
50 * be static or malloc()'d memory. But stack space is the most common use
53 * 'base' should be appropriately aligned. Using an array of uint32_t or
54 * uint64_t for the buffer is a reasonable way to ensure appropriate alignment
55 * for 32- or 64-bit data. OFPBUF_STACK_BUFFER is a convenient way to do so.
57 * An ofpbuf operation that requires reallocating data will assert-fail if this
58 * function was used to initialize it. Thus, one need not call ofpbuf_uninit()
59 * on an ofpbuf initialized by this function (though doing so is harmless),
60 * because it is guaranteed that 'b' does not own any heap-allocated memory. */
62 ofpbuf_use_stack(struct ofpbuf *b, void *base, size_t allocated)
64 ofpbuf_use__(b, base, allocated, OFPBUF_STACK);
67 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
68 * memory starting at 'base'. 'base' should point to a buffer on the stack.
69 * (Nothing actually relies on 'base' being allocated on the stack. It could
70 * be static or malloc()'d memory. But stack space is the most common usen
73 * 'base' should be appropriately aligned. Using an array of uint32_t or
74 * uint64_t for the buffer is a reasonable way to ensure appropriate alignment
75 * for 32- or 64-bit data. OFPBUF_STACK_BUFFER is a convenient way to do so.
77 * An ofpbuf operation that requires reallocating data will copy the provided
78 * buffer into a malloc()'d buffer. Thus, it is wise to call ofpbuf_uninit()
79 * on an ofpbuf initialized by this function, so that if it expanded into the
80 * heap, that memory is freed. */
82 ofpbuf_use_stub(struct ofpbuf *b, void *base, size_t allocated)
84 ofpbuf_use__(b, base, allocated, OFPBUF_STUB);
87 /* Initializes 'b' as an ofpbuf whose data starts at 'data' and continues for
88 * 'size' bytes. This is appropriate for an ofpbuf that will be used to
89 * inspect existing data, without moving it around or reallocating it, and
90 * generally without modifying it at all.
92 * An ofpbuf operation that requires reallocating data will assert-fail if this
93 * function was used to initialize it. */
95 ofpbuf_use_const(struct ofpbuf *b, const void *data, size_t size)
97 ofpbuf_use__(b, CONST_CAST(void *, data), size, OFPBUF_STACK);
101 /* Initializes 'b' as an empty ofpbuf with an initial capacity of 'size'
104 ofpbuf_init(struct ofpbuf *b, size_t size)
106 ofpbuf_use(b, size ? xmalloc(size) : NULL, size);
109 /* Frees memory that 'b' points to. */
111 ofpbuf_uninit(struct ofpbuf *b)
113 if (b && b->source == OFPBUF_MALLOC) {
118 /* Returns a pointer that may be passed to free() to accomplish the same thing
119 * as ofpbuf_uninit(b). The return value is a null pointer if ofpbuf_uninit()
120 * would not free any memory. */
122 ofpbuf_get_uninit_pointer(struct ofpbuf *b)
124 return b && b->source == OFPBUF_MALLOC ? b->base : NULL;
127 /* Frees memory that 'b' points to and allocates a new ofpbuf */
129 ofpbuf_reinit(struct ofpbuf *b, size_t size)
132 ofpbuf_init(b, size);
135 /* Creates and returns a new ofpbuf with an initial capacity of 'size'
138 ofpbuf_new(size_t size)
140 struct ofpbuf *b = xmalloc(sizeof *b);
141 ofpbuf_init(b, size);
145 /* Creates and returns a new ofpbuf with an initial capacity of 'size +
146 * headroom' bytes, reserving the first 'headroom' bytes as headroom. */
148 ofpbuf_new_with_headroom(size_t size, size_t headroom)
150 struct ofpbuf *b = ofpbuf_new(size + headroom);
151 ofpbuf_reserve(b, headroom);
155 /* Creates and returns a new ofpbuf that initially contains a copy of the
156 * 'buffer->size' bytes of data starting at 'buffer->data' with no headroom or
159 ofpbuf_clone(const struct ofpbuf *buffer)
161 return ofpbuf_clone_with_headroom(buffer, 0);
164 /* Creates and returns a new ofpbuf whose data are copied from 'buffer'. The
165 * returned ofpbuf will additionally have 'headroom' bytes of headroom. */
167 ofpbuf_clone_with_headroom(const struct ofpbuf *buffer, size_t headroom)
169 struct ofpbuf *new_buffer;
170 uintptr_t data_delta;
172 new_buffer = ofpbuf_clone_data_with_headroom(buffer->data, buffer->size,
174 data_delta = (char *) new_buffer->data - (char *) buffer->data;
177 new_buffer->l2 = (char *) buffer->l2 + data_delta;
180 new_buffer->l3 = (char *) buffer->l3 + data_delta;
183 new_buffer->l4 = (char *) buffer->l4 + data_delta;
186 new_buffer->l7 = (char *) buffer->l7 + data_delta;
192 /* Creates and returns a new ofpbuf that initially contains a copy of the
193 * 'size' bytes of data starting at 'data' with no headroom or tailroom. */
195 ofpbuf_clone_data(const void *data, size_t size)
197 return ofpbuf_clone_data_with_headroom(data, size, 0);
200 /* Creates and returns a new ofpbuf that initially contains 'headroom' bytes of
201 * headroom followed by a copy of the 'size' bytes of data starting at
204 ofpbuf_clone_data_with_headroom(const void *data, size_t size, size_t headroom)
206 struct ofpbuf *b = ofpbuf_new_with_headroom(size, headroom);
207 ofpbuf_put(b, data, size);
211 /* Frees memory that 'b' points to, as well as 'b' itself. */
213 ofpbuf_delete(struct ofpbuf *b)
221 /* Returns the number of bytes of headroom in 'b', that is, the number of bytes
222 * of unused space in ofpbuf 'b' before the data that is in use. (Most
223 * commonly, the data in a ofpbuf is at its beginning, and thus the ofpbuf's
226 ofpbuf_headroom(const struct ofpbuf *b)
228 return (char*)b->data - (char*)b->base;
231 /* Returns the number of bytes that may be appended to the tail end of ofpbuf
232 * 'b' before the ofpbuf must be reallocated. */
234 ofpbuf_tailroom(const struct ofpbuf *b)
236 return (char*)ofpbuf_end(b) - (char*)ofpbuf_tail(b);
240 ofpbuf_copy__(struct ofpbuf *b, uint8_t *new_base,
241 size_t new_headroom, size_t new_tailroom)
243 const uint8_t *old_base = b->base;
244 size_t old_headroom = ofpbuf_headroom(b);
245 size_t old_tailroom = ofpbuf_tailroom(b);
246 size_t copy_headroom = MIN(old_headroom, new_headroom);
247 size_t copy_tailroom = MIN(old_tailroom, new_tailroom);
249 memcpy(&new_base[new_headroom - copy_headroom],
250 &old_base[old_headroom - copy_headroom],
251 copy_headroom + b->size + copy_tailroom);
254 /* Reallocates 'b' so that it has exactly 'new_headroom' and 'new_tailroom'
255 * bytes of headroom and tailroom, respectively. */
257 ofpbuf_resize__(struct ofpbuf *b, size_t new_headroom, size_t new_tailroom)
259 void *new_base, *new_data;
260 size_t new_allocated;
262 new_allocated = new_headroom + b->size + new_tailroom;
266 if (new_headroom == ofpbuf_headroom(b)) {
267 new_base = xrealloc(b->base, new_allocated);
269 new_base = xmalloc(new_allocated);
270 ofpbuf_copy__(b, new_base, new_headroom, new_tailroom);
279 b->source = OFPBUF_MALLOC;
280 new_base = xmalloc(new_allocated);
281 ofpbuf_copy__(b, new_base, new_headroom, new_tailroom);
288 b->allocated = new_allocated;
291 new_data = (char *) new_base + new_headroom;
292 if (b->data != new_data) {
293 uintptr_t data_delta = (char *) new_data - (char *) b->data;
296 b->l2 = (char *) b->l2 + data_delta;
299 b->l3 = (char *) b->l3 + data_delta;
302 b->l4 = (char *) b->l4 + data_delta;
305 b->l7 = (char *) b->l7 + data_delta;
310 /* Ensures that 'b' has room for at least 'size' bytes at its tail end,
311 * reallocating and copying its data if necessary. Its headroom, if any, is
314 ofpbuf_prealloc_tailroom(struct ofpbuf *b, size_t size)
316 if (size > ofpbuf_tailroom(b)) {
317 ofpbuf_resize__(b, ofpbuf_headroom(b), MAX(size, 64));
321 /* Ensures that 'b' has room for at least 'size' bytes at its head,
322 * reallocating and copying its data if necessary. Its tailroom, if any, is
325 ofpbuf_prealloc_headroom(struct ofpbuf *b, size_t size)
327 if (size > ofpbuf_headroom(b)) {
328 ofpbuf_resize__(b, MAX(size, 64), ofpbuf_tailroom(b));
332 /* Trims the size of 'b' to fit its actual content, reducing its tailroom to
333 * 0. Its headroom, if any, is preserved.
335 * Buffers not obtained from malloc() are not resized, since that wouldn't save
338 ofpbuf_trim(struct ofpbuf *b)
340 if (b->source == OFPBUF_MALLOC
341 && (ofpbuf_headroom(b) || ofpbuf_tailroom(b))) {
342 ofpbuf_resize__(b, 0, 0);
346 /* If 'b' is shorter than 'length' bytes, pads its tail out with zeros to that
349 ofpbuf_padto(struct ofpbuf *b, size_t length)
351 if (b->size < length) {
352 ofpbuf_put_zeros(b, length - b->size);
356 /* Appends 'size' bytes of data to the tail end of 'b', reallocating and
357 * copying its data if necessary. Returns a pointer to the first byte of the
358 * new data, which is left uninitialized. */
360 ofpbuf_put_uninit(struct ofpbuf *b, size_t size)
363 ofpbuf_prealloc_tailroom(b, size);
369 /* Appends 'size' zeroed bytes to the tail end of 'b'. Data in 'b' is
370 * reallocated and copied if necessary. Returns a pointer to the first byte of
371 * the data's location in the ofpbuf. */
373 ofpbuf_put_zeros(struct ofpbuf *b, size_t size)
375 void *dst = ofpbuf_put_uninit(b, size);
376 memset(dst, 0, size);
380 /* Appends the 'size' bytes of data in 'p' to the tail end of 'b'. Data in 'b'
381 * is reallocated and copied if necessary. Returns a pointer to the first
382 * byte of the data's location in the ofpbuf. */
384 ofpbuf_put(struct ofpbuf *b, const void *p, size_t size)
386 void *dst = ofpbuf_put_uninit(b, size);
387 memcpy(dst, p, size);
391 /* Parses as many pairs of hex digits as possible (possibly separated by
392 * spaces) from the beginning of 's', appending bytes for their values to 'b'.
393 * Returns the first character of 's' that is not the first of a pair of hex
394 * digits. If 'n' is nonnull, stores the number of bytes added to 'b' in
397 ofpbuf_put_hex(struct ofpbuf *b, const char *s, size_t *n)
399 size_t initial_size = b->size;
405 byte = hexits_value(s, 2, &ok);
408 *n = b->size - initial_size;
410 return CONST_CAST(char *, s);
413 ofpbuf_put(b, &byte, 1);
418 /* Reserves 'size' bytes of headroom so that they can be later allocated with
419 * ofpbuf_push_uninit() without reallocating the ofpbuf. */
421 ofpbuf_reserve(struct ofpbuf *b, size_t size)
423 ovs_assert(!b->size);
424 ofpbuf_prealloc_tailroom(b, size);
425 b->data = (char*)b->data + size;
428 /* Prefixes 'size' bytes to the head end of 'b', reallocating and copying its
429 * data if necessary. Returns a pointer to the first byte of the data's
430 * location in the ofpbuf. The new data is left uninitialized. */
432 ofpbuf_push_uninit(struct ofpbuf *b, size_t size)
434 ofpbuf_prealloc_headroom(b, size);
435 b->data = (char*)b->data - size;
440 /* Prefixes 'size' zeroed bytes to the head end of 'b', reallocating and
441 * copying its data if necessary. Returns a pointer to the first byte of the
442 * data's location in the ofpbuf. */
444 ofpbuf_push_zeros(struct ofpbuf *b, size_t size)
446 void *dst = ofpbuf_push_uninit(b, size);
447 memset(dst, 0, size);
451 /* Copies the 'size' bytes starting at 'p' to the head end of 'b', reallocating
452 * and copying its data if necessary. Returns a pointer to the first byte of
453 * the data's location in the ofpbuf. */
455 ofpbuf_push(struct ofpbuf *b, const void *p, size_t size)
457 void *dst = ofpbuf_push_uninit(b, size);
458 memcpy(dst, p, size);
462 /* If 'b' contains at least 'offset + size' bytes of data, returns a pointer to
463 * byte 'offset'. Otherwise, returns a null pointer. */
465 ofpbuf_at(const struct ofpbuf *b, size_t offset, size_t size)
467 return offset + size <= b->size ? (char *) b->data + offset : NULL;
470 /* Returns a pointer to byte 'offset' in 'b', which must contain at least
471 * 'offset + size' bytes of data. */
473 ofpbuf_at_assert(const struct ofpbuf *b, size_t offset, size_t size)
475 ovs_assert(offset + size <= b->size);
476 return ((char *) b->data) + offset;
479 /* Returns the byte following the last byte of data in use in 'b'. */
481 ofpbuf_tail(const struct ofpbuf *b)
483 return (char *) b->data + b->size;
486 /* Returns the byte following the last byte allocated for use (but not
487 * necessarily in use) by 'b'. */
489 ofpbuf_end(const struct ofpbuf *b)
491 return (char *) b->base + b->allocated;
494 /* Clears any data from 'b'. */
496 ofpbuf_clear(struct ofpbuf *b)
502 /* Removes 'size' bytes from the head end of 'b', which must contain at least
503 * 'size' bytes of data. Returns the first byte of data removed. */
505 ofpbuf_pull(struct ofpbuf *b, size_t size)
507 void *data = b->data;
508 ovs_assert(b->size >= size);
509 b->data = (char*)b->data + size;
514 /* If 'b' has at least 'size' bytes of data, removes that many bytes from the
515 * head end of 'b' and returns the first byte removed. Otherwise, returns a
516 * null pointer without modifying 'b'. */
518 ofpbuf_try_pull(struct ofpbuf *b, size_t size)
520 return b->size >= size ? ofpbuf_pull(b, size) : NULL;
523 /* Returns the data in 'b' as a block of malloc()'d memory and frees the buffer
524 * within 'b'. (If 'b' itself was dynamically allocated, e.g. with
525 * ofpbuf_new(), then it should still be freed with, e.g., ofpbuf_delete().) */
527 ofpbuf_steal_data(struct ofpbuf *b)
530 if (b->source == OFPBUF_MALLOC && b->data == b->base) {
533 p = xmemdup(b->data, b->size);
534 if (b->source == OFPBUF_MALLOC) {
538 b->base = b->data = NULL;
542 /* Returns a string that describes some of 'b''s metadata plus a hex dump of up
543 * to 'maxbytes' from the start of the buffer. */
545 ofpbuf_to_string(const struct ofpbuf *b, size_t maxbytes)
550 ds_put_format(&s, "size=%zu, allocated=%zu, head=%zu, tail=%zu\n",
551 b->size, b->allocated,
552 ofpbuf_headroom(b), ofpbuf_tailroom(b));
553 ds_put_hex_dump(&s, b->data, MIN(b->size, maxbytes), 0, false);
557 /* Removes each of the "struct ofpbuf"s on 'list' from the list and frees
560 ofpbuf_list_delete(struct list *list)
562 struct ofpbuf *b, *next;
564 LIST_FOR_EACH_SAFE (b, next, list_node, list) {
565 list_remove(&b->list_node);