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.
22 #include "dynamic-string.h"
26 ofpbuf_use__(struct ofpbuf *b, void *base, size_t allocated,
27 enum ofpbuf_source source)
29 b->base = b->data = base;
30 b->allocated = allocated;
33 b->l2 = b->l3 = b->l4 = b->l7 = NULL;
34 list_poison(&b->list_node);
38 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
39 * memory starting at 'base'. 'base' should be the first byte of a region
40 * obtained from malloc(). It will be freed (with free()) if 'b' is resized or
43 ofpbuf_use(struct ofpbuf *b, void *base, size_t allocated)
45 ofpbuf_use__(b, base, allocated, OFPBUF_MALLOC);
48 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
49 * memory starting at 'base'. 'base' should point to a buffer on the stack.
50 * (Nothing actually relies on 'base' being allocated on the stack. It could
51 * be static or malloc()'d memory. But stack space is the most common use
54 * 'base' should be appropriately aligned. Using an array of uint32_t or
55 * uint64_t for the buffer is a reasonable way to ensure appropriate alignment
56 * for 32- or 64-bit data. OFPBUF_STACK_BUFFER is a convenient way to do so.
58 * An ofpbuf operation that requires reallocating data will assert-fail if this
59 * function was used to initialize it. Thus, one need not call ofpbuf_uninit()
60 * on an ofpbuf initialized by this function (though doing so is harmless),
61 * because it is guaranteed that 'b' does not own any heap-allocated memory. */
63 ofpbuf_use_stack(struct ofpbuf *b, void *base, size_t allocated)
65 ofpbuf_use__(b, base, allocated, OFPBUF_STACK);
68 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
69 * memory starting at 'base'. 'base' should point to a buffer on the stack.
70 * (Nothing actually relies on 'base' being allocated on the stack. It could
71 * be static or malloc()'d memory. But stack space is the most common usen
74 * 'base' should be appropriately aligned. Using an array of uint32_t or
75 * uint64_t for the buffer is a reasonable way to ensure appropriate alignment
76 * for 32- or 64-bit data. OFPBUF_STACK_BUFFER is a convenient way to do so.
78 * An ofpbuf operation that requires reallocating data will copy the provided
79 * buffer into a malloc()'d buffer. Thus, it is wise to call ofpbuf_uninit()
80 * on an ofpbuf initialized by this function, so that if it expanded into the
81 * heap, that memory is freed. */
83 ofpbuf_use_stub(struct ofpbuf *b, void *base, size_t allocated)
85 ofpbuf_use__(b, base, allocated, OFPBUF_STUB);
88 /* Initializes 'b' as an ofpbuf whose data starts at 'data' and continues for
89 * 'size' bytes. This is appropriate for an ofpbuf that will be used to
90 * inspect existing data, without moving it around or reallocating it, and
91 * generally without modifying it at all.
93 * An ofpbuf operation that requires reallocating data will assert-fail if this
94 * function was used to initialize it. */
96 ofpbuf_use_const(struct ofpbuf *b, const void *data, size_t size)
98 ofpbuf_use__(b, CONST_CAST(void *, data), size, OFPBUF_STACK);
102 /* Initializes 'b' as an empty ofpbuf with an initial capacity of 'size'
105 ofpbuf_init(struct ofpbuf *b, size_t size)
107 ofpbuf_use(b, size ? xmalloc(size) : NULL, size);
110 /* Frees memory that 'b' points to. */
112 ofpbuf_uninit(struct ofpbuf *b)
114 if (b && b->source == OFPBUF_MALLOC) {
119 /* Returns a pointer that may be passed to free() to accomplish the same thing
120 * as ofpbuf_uninit(b). The return value is a null pointer if ofpbuf_uninit()
121 * would not free any memory. */
123 ofpbuf_get_uninit_pointer(struct ofpbuf *b)
125 return b && b->source == OFPBUF_MALLOC ? b->base : NULL;
128 /* Frees memory that 'b' points to and allocates a new ofpbuf */
130 ofpbuf_reinit(struct ofpbuf *b, size_t size)
133 ofpbuf_init(b, size);
136 /* Creates and returns a new ofpbuf with an initial capacity of 'size'
139 ofpbuf_new(size_t size)
141 struct ofpbuf *b = xmalloc(sizeof *b);
142 ofpbuf_init(b, size);
146 /* Creates and returns a new ofpbuf with an initial capacity of 'size +
147 * headroom' bytes, reserving the first 'headroom' bytes as headroom. */
149 ofpbuf_new_with_headroom(size_t size, size_t headroom)
151 struct ofpbuf *b = ofpbuf_new(size + headroom);
152 ofpbuf_reserve(b, headroom);
156 /* Creates and returns a new ofpbuf that initially contains a copy of the
157 * 'buffer->size' bytes of data starting at 'buffer->data' with no headroom or
160 ofpbuf_clone(const struct ofpbuf *buffer)
162 return ofpbuf_clone_with_headroom(buffer, 0);
165 /* Creates and returns a new ofpbuf whose data are copied from 'buffer'. The
166 * returned ofpbuf will additionally have 'headroom' bytes of headroom. */
168 ofpbuf_clone_with_headroom(const struct ofpbuf *buffer, size_t headroom)
170 struct ofpbuf *new_buffer;
171 uintptr_t data_delta;
173 new_buffer = ofpbuf_clone_data_with_headroom(buffer->data, buffer->size,
175 data_delta = (char *) new_buffer->data - (char *) buffer->data;
178 new_buffer->l2 = (char *) buffer->l2 + data_delta;
181 new_buffer->l3 = (char *) buffer->l3 + data_delta;
184 new_buffer->l4 = (char *) buffer->l4 + data_delta;
187 new_buffer->l7 = (char *) buffer->l7 + data_delta;
193 /* Creates and returns a new ofpbuf that initially contains a copy of the
194 * 'size' bytes of data starting at 'data' with no headroom or tailroom. */
196 ofpbuf_clone_data(const void *data, size_t size)
198 return ofpbuf_clone_data_with_headroom(data, size, 0);
201 /* Creates and returns a new ofpbuf that initially contains 'headroom' bytes of
202 * headroom followed by a copy of the 'size' bytes of data starting at
205 ofpbuf_clone_data_with_headroom(const void *data, size_t size, size_t headroom)
207 struct ofpbuf *b = ofpbuf_new_with_headroom(size, headroom);
208 ofpbuf_put(b, data, size);
212 /* Frees memory that 'b' points to, as well as 'b' itself. */
214 ofpbuf_delete(struct ofpbuf *b)
222 /* Returns the number of bytes of headroom in 'b', that is, the number of bytes
223 * of unused space in ofpbuf 'b' before the data that is in use. (Most
224 * commonly, the data in a ofpbuf is at its beginning, and thus the ofpbuf's
227 ofpbuf_headroom(const struct ofpbuf *b)
229 return (char*)b->data - (char*)b->base;
232 /* Returns the number of bytes that may be appended to the tail end of ofpbuf
233 * 'b' before the ofpbuf must be reallocated. */
235 ofpbuf_tailroom(const struct ofpbuf *b)
237 return (char*)ofpbuf_end(b) - (char*)ofpbuf_tail(b);
241 ofpbuf_copy__(struct ofpbuf *b, uint8_t *new_base,
242 size_t new_headroom, size_t new_tailroom)
244 const uint8_t *old_base = b->base;
245 size_t old_headroom = ofpbuf_headroom(b);
246 size_t old_tailroom = ofpbuf_tailroom(b);
247 size_t copy_headroom = MIN(old_headroom, new_headroom);
248 size_t copy_tailroom = MIN(old_tailroom, new_tailroom);
250 memcpy(&new_base[new_headroom - copy_headroom],
251 &old_base[old_headroom - copy_headroom],
252 copy_headroom + b->size + copy_tailroom);
255 /* Reallocates 'b' so that it has exactly 'new_headroom' and 'new_tailroom'
256 * bytes of headroom and tailroom, respectively. */
258 ofpbuf_resize__(struct ofpbuf *b, size_t new_headroom, size_t new_tailroom)
260 void *new_base, *new_data;
261 size_t new_allocated;
263 new_allocated = new_headroom + b->size + new_tailroom;
267 if (new_headroom == ofpbuf_headroom(b)) {
268 new_base = xrealloc(b->base, new_allocated);
270 new_base = xmalloc(new_allocated);
271 ofpbuf_copy__(b, new_base, new_headroom, new_tailroom);
280 b->source = OFPBUF_MALLOC;
281 new_base = xmalloc(new_allocated);
282 ofpbuf_copy__(b, new_base, new_headroom, new_tailroom);
289 b->allocated = new_allocated;
292 new_data = (char *) new_base + new_headroom;
293 if (b->data != new_data) {
294 uintptr_t data_delta = (char *) new_data - (char *) b->data;
297 b->l2 = (char *) b->l2 + data_delta;
300 b->l3 = (char *) b->l3 + data_delta;
303 b->l4 = (char *) b->l4 + data_delta;
306 b->l7 = (char *) b->l7 + data_delta;
311 /* Ensures that 'b' has room for at least 'size' bytes at its tail end,
312 * reallocating and copying its data if necessary. Its headroom, if any, is
315 ofpbuf_prealloc_tailroom(struct ofpbuf *b, size_t size)
317 if (size > ofpbuf_tailroom(b)) {
318 ofpbuf_resize__(b, ofpbuf_headroom(b), MAX(size, 64));
322 /* Ensures that 'b' has room for at least 'size' bytes at its head,
323 * reallocating and copying its data if necessary. Its tailroom, if any, is
326 ofpbuf_prealloc_headroom(struct ofpbuf *b, size_t size)
328 if (size > ofpbuf_headroom(b)) {
329 ofpbuf_resize__(b, MAX(size, 64), ofpbuf_tailroom(b));
333 /* Trims the size of 'b' to fit its actual content, reducing its tailroom to
334 * 0. Its headroom, if any, is preserved.
336 * Buffers not obtained from malloc() are not resized, since that wouldn't save
339 ofpbuf_trim(struct ofpbuf *b)
341 if (b->source == OFPBUF_MALLOC
342 && (ofpbuf_headroom(b) || ofpbuf_tailroom(b))) {
343 ofpbuf_resize__(b, 0, 0);
347 /* If 'b' is shorter than 'length' bytes, pads its tail out with zeros to that
350 ofpbuf_padto(struct ofpbuf *b, size_t length)
352 if (b->size < length) {
353 ofpbuf_put_zeros(b, length - b->size);
357 /* Appends 'size' bytes of data to the tail end of 'b', reallocating and
358 * copying its data if necessary. Returns a pointer to the first byte of the
359 * new data, which is left uninitialized. */
361 ofpbuf_put_uninit(struct ofpbuf *b, size_t size)
364 ofpbuf_prealloc_tailroom(b, size);
370 /* Appends 'size' zeroed bytes to the tail end of 'b'. Data in 'b' is
371 * reallocated and copied if necessary. Returns a pointer to the first byte of
372 * the data's location in the ofpbuf. */
374 ofpbuf_put_zeros(struct ofpbuf *b, size_t size)
376 void *dst = ofpbuf_put_uninit(b, size);
377 memset(dst, 0, size);
381 /* Appends the 'size' bytes of data in 'p' to the tail end of 'b'. Data in 'b'
382 * is reallocated and copied if necessary. Returns a pointer to the first
383 * byte of the data's location in the ofpbuf. */
385 ofpbuf_put(struct ofpbuf *b, const void *p, size_t size)
387 void *dst = ofpbuf_put_uninit(b, size);
388 memcpy(dst, p, size);
392 /* Parses as many pairs of hex digits as possible (possibly separated by
393 * spaces) from the beginning of 's', appending bytes for their values to 'b'.
394 * Returns the first character of 's' that is not the first of a pair of hex
395 * digits. If 'n' is nonnull, stores the number of bytes added to 'b' in
398 ofpbuf_put_hex(struct ofpbuf *b, const char *s, size_t *n)
400 size_t initial_size = b->size;
406 byte = hexits_value(s, 2, &ok);
409 *n = b->size - initial_size;
411 return CONST_CAST(char *, s);
414 ofpbuf_put(b, &byte, 1);
419 /* Reserves 'size' bytes of headroom so that they can be later allocated with
420 * ofpbuf_push_uninit() without reallocating the ofpbuf. */
422 ofpbuf_reserve(struct ofpbuf *b, size_t size)
425 ofpbuf_prealloc_tailroom(b, size);
426 b->data = (char*)b->data + size;
429 /* Prefixes 'size' bytes to the head end of 'b', reallocating and copying its
430 * data if necessary. Returns a pointer to the first byte of the data's
431 * location in the ofpbuf. The new data is left uninitialized. */
433 ofpbuf_push_uninit(struct ofpbuf *b, size_t size)
435 ofpbuf_prealloc_headroom(b, size);
436 b->data = (char*)b->data - size;
441 /* Prefixes 'size' zeroed bytes to the head end of 'b', reallocating and
442 * copying its data if necessary. Returns a pointer to the first byte of the
443 * data's location in the ofpbuf. */
445 ofpbuf_push_zeros(struct ofpbuf *b, size_t size)
447 void *dst = ofpbuf_push_uninit(b, size);
448 memset(dst, 0, size);
452 /* Copies the 'size' bytes starting at 'p' to the head end of 'b', reallocating
453 * and copying its data if necessary. Returns a pointer to the first byte of
454 * the data's location in the ofpbuf. */
456 ofpbuf_push(struct ofpbuf *b, const void *p, size_t size)
458 void *dst = ofpbuf_push_uninit(b, size);
459 memcpy(dst, p, size);
463 /* If 'b' contains at least 'offset + size' bytes of data, returns a pointer to
464 * byte 'offset'. Otherwise, returns a null pointer. */
466 ofpbuf_at(const struct ofpbuf *b, size_t offset, size_t size)
468 return offset + size <= b->size ? (char *) b->data + offset : NULL;
471 /* Returns a pointer to byte 'offset' in 'b', which must contain at least
472 * 'offset + size' bytes of data. */
474 ofpbuf_at_assert(const struct ofpbuf *b, size_t offset, size_t size)
476 assert(offset + size <= b->size);
477 return ((char *) b->data) + offset;
480 /* Returns the byte following the last byte of data in use in 'b'. */
482 ofpbuf_tail(const struct ofpbuf *b)
484 return (char *) b->data + b->size;
487 /* Returns the byte following the last byte allocated for use (but not
488 * necessarily in use) by 'b'. */
490 ofpbuf_end(const struct ofpbuf *b)
492 return (char *) b->base + b->allocated;
495 /* Clears any data from 'b'. */
497 ofpbuf_clear(struct ofpbuf *b)
503 /* Removes 'size' bytes from the head end of 'b', which must contain at least
504 * 'size' bytes of data. Returns the first byte of data removed. */
506 ofpbuf_pull(struct ofpbuf *b, size_t size)
508 void *data = b->data;
509 assert(b->size >= size);
510 b->data = (char*)b->data + size;
515 /* If 'b' has at least 'size' bytes of data, removes that many bytes from the
516 * head end of 'b' and returns the first byte removed. Otherwise, returns a
517 * null pointer without modifying 'b'. */
519 ofpbuf_try_pull(struct ofpbuf *b, size_t size)
521 return b->size >= size ? ofpbuf_pull(b, size) : NULL;
524 /* Returns the data in 'b' as a block of malloc()'d memory and frees the buffer
525 * within 'b'. (If 'b' itself was dynamically allocated, e.g. with
526 * ofpbuf_new(), then it should still be freed with, e.g., ofpbuf_delete().) */
528 ofpbuf_steal_data(struct ofpbuf *b)
531 if (b->source == OFPBUF_MALLOC && b->data == b->base) {
534 p = xmemdup(b->data, b->size);
535 if (b->source == OFPBUF_MALLOC) {
539 b->base = b->data = NULL;
543 /* Returns a string that describes some of 'b''s metadata plus a hex dump of up
544 * to 'maxbytes' from the start of the buffer. */
546 ofpbuf_to_string(const struct ofpbuf *b, size_t maxbytes)
551 ds_put_format(&s, "size=%zu, allocated=%zu, head=%zu, tail=%zu\n",
552 b->size, b->allocated,
553 ofpbuf_headroom(b), ofpbuf_tailroom(b));
554 ds_put_hex_dump(&s, b->data, MIN(b->size, maxbytes), 0, false);
558 /* Removes each of the "struct ofpbuf"s on 'list' from the list and frees
561 ofpbuf_list_delete(struct list *list)
563 struct ofpbuf *b, *next;
565 LIST_FOR_EACH_SAFE (b, next, list_node, list) {
566 list_remove(&b->list_node);