2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 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->l2_5 = 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.
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 use
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.
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->l2_5 = (char *) buffer->l2_5 + data_delta;
183 new_buffer->l3 = (char *) buffer->l3 + data_delta;
186 new_buffer->l4 = (char *) buffer->l4 + data_delta;
189 new_buffer->l7 = (char *) buffer->l7 + data_delta;
195 /* Creates and returns a new ofpbuf that initially contains a copy of the
196 * 'size' bytes of data starting at 'data' with no headroom or tailroom. */
198 ofpbuf_clone_data(const void *data, size_t size)
200 return ofpbuf_clone_data_with_headroom(data, size, 0);
203 /* Creates and returns a new ofpbuf that initially contains 'headroom' bytes of
204 * headroom followed by a copy of the 'size' bytes of data starting at
207 ofpbuf_clone_data_with_headroom(const void *data, size_t size, size_t headroom)
209 struct ofpbuf *b = ofpbuf_new_with_headroom(size, headroom);
210 ofpbuf_put(b, data, size);
214 /* Frees memory that 'b' points to, as well as 'b' itself. */
216 ofpbuf_delete(struct ofpbuf *b)
224 /* Returns the number of bytes of headroom in 'b', that is, the number of bytes
225 * of unused space in ofpbuf 'b' before the data that is in use. (Most
226 * commonly, the data in a ofpbuf is at its beginning, and thus the ofpbuf's
229 ofpbuf_headroom(const struct ofpbuf *b)
231 return (char*)b->data - (char*)b->base;
234 /* Returns the number of bytes that may be appended to the tail end of ofpbuf
235 * 'b' before the ofpbuf must be reallocated. */
237 ofpbuf_tailroom(const struct ofpbuf *b)
239 return (char*)ofpbuf_end(b) - (char*)ofpbuf_tail(b);
243 ofpbuf_copy__(struct ofpbuf *b, uint8_t *new_base,
244 size_t new_headroom, size_t new_tailroom)
246 const uint8_t *old_base = b->base;
247 size_t old_headroom = ofpbuf_headroom(b);
248 size_t old_tailroom = ofpbuf_tailroom(b);
249 size_t copy_headroom = MIN(old_headroom, new_headroom);
250 size_t copy_tailroom = MIN(old_tailroom, new_tailroom);
252 memcpy(&new_base[new_headroom - copy_headroom],
253 &old_base[old_headroom - copy_headroom],
254 copy_headroom + b->size + copy_tailroom);
257 /* Reallocates 'b' so that it has exactly 'new_headroom' and 'new_tailroom'
258 * bytes of headroom and tailroom, respectively. */
260 ofpbuf_resize__(struct ofpbuf *b, size_t new_headroom, size_t new_tailroom)
262 void *new_base, *new_data;
263 size_t new_allocated;
265 new_allocated = new_headroom + b->size + new_tailroom;
269 if (new_headroom == ofpbuf_headroom(b)) {
270 new_base = xrealloc(b->base, new_allocated);
272 new_base = xmalloc(new_allocated);
273 ofpbuf_copy__(b, new_base, new_headroom, new_tailroom);
282 b->source = OFPBUF_MALLOC;
283 new_base = xmalloc(new_allocated);
284 ofpbuf_copy__(b, new_base, new_headroom, new_tailroom);
291 b->allocated = new_allocated;
294 new_data = (char *) new_base + new_headroom;
295 if (b->data != new_data) {
296 uintptr_t data_delta = (char *) new_data - (char *) b->data;
299 b->l2 = (char *) b->l2 + data_delta;
302 b->l2_5 = (char *) b->l2_5 + data_delta;
305 b->l3 = (char *) b->l3 + data_delta;
308 b->l4 = (char *) b->l4 + data_delta;
311 b->l7 = (char *) b->l7 + data_delta;
316 /* Ensures that 'b' has room for at least 'size' bytes at its tail end,
317 * reallocating and copying its data if necessary. Its headroom, if any, is
320 ofpbuf_prealloc_tailroom(struct ofpbuf *b, size_t size)
322 if (size > ofpbuf_tailroom(b)) {
323 ofpbuf_resize__(b, ofpbuf_headroom(b), MAX(size, 64));
327 /* Ensures that 'b' has room for at least 'size' bytes at its head,
328 * reallocating and copying its data if necessary. Its tailroom, if any, is
331 ofpbuf_prealloc_headroom(struct ofpbuf *b, size_t size)
333 if (size > ofpbuf_headroom(b)) {
334 ofpbuf_resize__(b, MAX(size, 64), ofpbuf_tailroom(b));
338 /* Trims the size of 'b' to fit its actual content, reducing its tailroom to
339 * 0. Its headroom, if any, is preserved.
341 * Buffers not obtained from malloc() are not resized, since that wouldn't save
344 ofpbuf_trim(struct ofpbuf *b)
346 if (b->source == OFPBUF_MALLOC
347 && (ofpbuf_headroom(b) || ofpbuf_tailroom(b))) {
348 ofpbuf_resize__(b, 0, 0);
352 /* If 'b' is shorter than 'length' bytes, pads its tail out with zeros to that
355 ofpbuf_padto(struct ofpbuf *b, size_t length)
357 if (b->size < length) {
358 ofpbuf_put_zeros(b, length - b->size);
362 /* Shifts all of the data within the allocated space in 'b' by 'delta' bytes.
363 * For example, a 'delta' of 1 would cause each byte of data to move one byte
364 * forward (from address 'p' to 'p+1'), and a 'delta' of -1 would cause each
365 * byte to move one byte backward (from 'p' to 'p-1'). */
367 ofpbuf_shift(struct ofpbuf *b, int delta)
369 ovs_assert(delta > 0 ? delta <= ofpbuf_tailroom(b)
370 : delta < 0 ? -delta <= ofpbuf_headroom(b)
374 char *dst = (char *) b->data + delta;
375 memmove(dst, b->data, b->size);
380 /* Appends 'size' bytes of data to the tail end of 'b', reallocating and
381 * copying its data if necessary. Returns a pointer to the first byte of the
382 * new data, which is left uninitialized. */
384 ofpbuf_put_uninit(struct ofpbuf *b, size_t size)
387 ofpbuf_prealloc_tailroom(b, size);
393 /* Appends 'size' zeroed bytes to the tail end of 'b'. Data in 'b' is
394 * reallocated and copied if necessary. Returns a pointer to the first byte of
395 * the data's location in the ofpbuf. */
397 ofpbuf_put_zeros(struct ofpbuf *b, size_t size)
399 void *dst = ofpbuf_put_uninit(b, size);
400 memset(dst, 0, size);
404 /* Appends the 'size' bytes of data in 'p' to the tail end of 'b'. Data in 'b'
405 * is reallocated and copied if necessary. Returns a pointer to the first
406 * byte of the data's location in the ofpbuf. */
408 ofpbuf_put(struct ofpbuf *b, const void *p, size_t size)
410 void *dst = ofpbuf_put_uninit(b, size);
411 memcpy(dst, p, size);
415 /* Parses as many pairs of hex digits as possible (possibly separated by
416 * spaces) from the beginning of 's', appending bytes for their values to 'b'.
417 * Returns the first character of 's' that is not the first of a pair of hex
418 * digits. If 'n' is nonnull, stores the number of bytes added to 'b' in
421 ofpbuf_put_hex(struct ofpbuf *b, const char *s, size_t *n)
423 size_t initial_size = b->size;
428 s += strspn(s, " \t\r\n");
429 byte = hexits_value(s, 2, &ok);
432 *n = b->size - initial_size;
434 return CONST_CAST(char *, s);
437 ofpbuf_put(b, &byte, 1);
442 /* Reserves 'size' bytes of headroom so that they can be later allocated with
443 * ofpbuf_push_uninit() without reallocating the ofpbuf. */
445 ofpbuf_reserve(struct ofpbuf *b, size_t size)
447 ovs_assert(!b->size);
448 ofpbuf_prealloc_tailroom(b, size);
449 b->data = (char*)b->data + size;
452 /* Reserves 'size' bytes of headroom so that they can be later allocated with
453 * ofpbuf_push_uninit() without reallocating the ofpbuf. */
455 ofpbuf_reserve_with_tailroom(struct ofpbuf *b, size_t headroom,
458 ovs_assert(!b->size);
459 ofpbuf_prealloc_tailroom(b, headroom + tailroom);
460 b->data = (char*)b->data + headroom;
463 /* Prefixes 'size' bytes to the head end of 'b', reallocating and copying its
464 * data if necessary. Returns a pointer to the first byte of the data's
465 * location in the ofpbuf. The new data is left uninitialized. */
467 ofpbuf_push_uninit(struct ofpbuf *b, size_t size)
469 ofpbuf_prealloc_headroom(b, size);
470 b->data = (char*)b->data - size;
475 /* Prefixes 'size' zeroed bytes to the head end of 'b', reallocating and
476 * copying its data if necessary. Returns a pointer to the first byte of the
477 * data's location in the ofpbuf. */
479 ofpbuf_push_zeros(struct ofpbuf *b, size_t size)
481 void *dst = ofpbuf_push_uninit(b, size);
482 memset(dst, 0, size);
486 /* Copies the 'size' bytes starting at 'p' to the head end of 'b', reallocating
487 * and copying its data if necessary. Returns a pointer to the first byte of
488 * the data's location in the ofpbuf. */
490 ofpbuf_push(struct ofpbuf *b, const void *p, size_t size)
492 void *dst = ofpbuf_push_uninit(b, size);
493 memcpy(dst, p, size);
497 /* If 'b' contains at least 'offset + size' bytes of data, returns a pointer to
498 * byte 'offset'. Otherwise, returns a null pointer. */
500 ofpbuf_at(const struct ofpbuf *b, size_t offset, size_t size)
502 return offset + size <= b->size ? (char *) b->data + offset : NULL;
505 /* Returns a pointer to byte 'offset' in 'b', which must contain at least
506 * 'offset + size' bytes of data. */
508 ofpbuf_at_assert(const struct ofpbuf *b, size_t offset, size_t size)
510 ovs_assert(offset + size <= b->size);
511 return ((char *) b->data) + offset;
514 /* Returns the byte following the last byte of data in use in 'b'. */
516 ofpbuf_tail(const struct ofpbuf *b)
518 return (char *) b->data + b->size;
521 /* Returns the byte following the last byte allocated for use (but not
522 * necessarily in use) by 'b'. */
524 ofpbuf_end(const struct ofpbuf *b)
526 return (char *) b->base + b->allocated;
529 /* Clears any data from 'b'. */
531 ofpbuf_clear(struct ofpbuf *b)
537 /* Removes 'size' bytes from the head end of 'b', which must contain at least
538 * 'size' bytes of data. Returns the first byte of data removed. */
540 ofpbuf_pull(struct ofpbuf *b, size_t size)
542 void *data = b->data;
543 ovs_assert(b->size >= size);
544 b->data = (char*)b->data + size;
549 /* If 'b' has at least 'size' bytes of data, removes that many bytes from the
550 * head end of 'b' and returns the first byte removed. Otherwise, returns a
551 * null pointer without modifying 'b'. */
553 ofpbuf_try_pull(struct ofpbuf *b, size_t size)
555 return b->size >= size ? ofpbuf_pull(b, size) : NULL;
558 /* Returns the data in 'b' as a block of malloc()'d memory and frees the buffer
559 * within 'b'. (If 'b' itself was dynamically allocated, e.g. with
560 * ofpbuf_new(), then it should still be freed with, e.g., ofpbuf_delete().) */
562 ofpbuf_steal_data(struct ofpbuf *b)
565 if (b->source == OFPBUF_MALLOC && b->data == b->base) {
568 p = xmemdup(b->data, b->size);
569 if (b->source == OFPBUF_MALLOC) {
573 b->base = b->data = NULL;
577 /* Returns a string that describes some of 'b''s metadata plus a hex dump of up
578 * to 'maxbytes' from the start of the buffer. */
580 ofpbuf_to_string(const struct ofpbuf *b, size_t maxbytes)
585 ds_put_format(&s, "size=%"PRIuSIZE", allocated=%"PRIuSIZE", head=%"PRIuSIZE", tail=%"PRIuSIZE"\n",
586 b->size, b->allocated,
587 ofpbuf_headroom(b), ofpbuf_tailroom(b));
588 ds_put_hex_dump(&s, b->data, MIN(b->size, maxbytes), 0, false);
592 /* Removes each of the "struct ofpbuf"s on 'list' from the list and frees
595 ofpbuf_list_delete(struct list *list)
597 struct ofpbuf *b, *next;
599 LIST_FOR_EACH_SAFE (b, next, list_node, list) {
600 list_remove(&b->list_node);