2 * Copyright (c) 2008, 2009, 2010 Nicira Networks.
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 * If 'b' is resized, new memory will be allocated with malloc() and 'base'
51 * will not be freed. This is useful when a small stack-allocated buffer is
52 * normally appropriate but sometimes it must be expanded.
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.
58 * (Nothing actually relies on 'base' being allocated on the stack. It could
59 * be static or malloc()'d memory. But stack space is the most common use
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 ofpbuf whose data starts at 'data' and continues for
68 * 'size' bytes. This is appropriate for an ofpbuf that will be used to
69 * inspect existing data, without moving it around or reallocating it, and
70 * generally without modifying it at all.
72 * An ofpbuf operation that requires reallocating data will assert-fail if this
73 * function was used to initialize it. */
75 ofpbuf_use_const(struct ofpbuf *b, const void *data, size_t size)
77 ofpbuf_use__(b, (void *) data, size, OFPBUF_CONST);
81 /* Initializes 'b' as an empty ofpbuf with an initial capacity of 'size'
84 ofpbuf_init(struct ofpbuf *b, size_t size)
86 ofpbuf_use(b, size ? xmalloc(size) : NULL, size);
89 /* Frees memory that 'b' points to. */
91 ofpbuf_uninit(struct ofpbuf *b)
93 if (b && b->source == OFPBUF_MALLOC) {
98 /* Frees memory that 'b' points to and allocates a new ofpbuf */
100 ofpbuf_reinit(struct ofpbuf *b, size_t size)
103 ofpbuf_init(b, size);
106 /* Creates and returns a new ofpbuf with an initial capacity of 'size'
109 ofpbuf_new(size_t size)
111 struct ofpbuf *b = xmalloc(sizeof *b);
112 ofpbuf_init(b, size);
116 /* Creates and returns a new ofpbuf with an initial capacity of 'size +
117 * headroom' bytes, reserving the first 'headroom' bytes as headroom. */
119 ofpbuf_new_with_headroom(size_t size, size_t headroom)
121 struct ofpbuf *b = ofpbuf_new(size + headroom);
122 ofpbuf_reserve(b, headroom);
127 ofpbuf_clone(const struct ofpbuf *buffer)
129 return ofpbuf_clone_data(buffer->data, buffer->size);
132 /* Creates and returns a new ofpbuf whose data are copied from 'buffer'. The
133 * returned ofpbuf will additionally have 'headroom' bytes of headroom. */
135 ofpbuf_clone_with_headroom(const struct ofpbuf *buffer, size_t headroom)
137 struct ofpbuf *b = ofpbuf_new_with_headroom(buffer->size, headroom);
138 ofpbuf_put(b, buffer->data, buffer->size);
143 ofpbuf_clone_data(const void *data, size_t size)
145 struct ofpbuf *b = ofpbuf_new(size);
146 ofpbuf_put(b, data, size);
150 /* Frees memory that 'b' points to, as well as 'b' itself. */
152 ofpbuf_delete(struct ofpbuf *b)
160 /* Returns the number of bytes of headroom in 'b', that is, the number of bytes
161 * of unused space in ofpbuf 'b' before the data that is in use. (Most
162 * commonly, the data in a ofpbuf is at its beginning, and thus the ofpbuf's
165 ofpbuf_headroom(const struct ofpbuf *b)
167 return (char*)b->data - (char*)b->base;
170 /* Returns the number of bytes that may be appended to the tail end of ofpbuf
171 * 'b' before the ofpbuf must be reallocated. */
173 ofpbuf_tailroom(const struct ofpbuf *b)
175 return (char*)ofpbuf_end(b) - (char*)ofpbuf_tail(b);
178 /* Changes 'b->base' to 'new_base' and adjusts all of 'b''s internal pointers
179 * to reflect the change. */
181 ofpbuf_rebase__(struct ofpbuf *b, void *new_base)
183 if (b->base != new_base) {
184 uintptr_t base_delta = (char*)new_base - (char*)b->base;
186 b->data = (char*)b->data + base_delta;
188 b->l2 = (char*)b->l2 + base_delta;
191 b->l3 = (char*)b->l3 + base_delta;
194 b->l4 = (char*)b->l4 + base_delta;
197 b->l7 = (char*)b->l7 + base_delta;
202 /* Reallocates 'b' so that it has exactly 'new_tailroom' bytes of tailroom. */
204 ofpbuf_resize_tailroom__(struct ofpbuf *b, size_t new_tailroom)
206 size_t new_allocated;
209 new_allocated = ofpbuf_headroom(b) + b->size + new_tailroom;
213 new_base = xrealloc(b->base, new_allocated);
217 new_base = xmalloc(new_allocated);
218 memcpy(new_base, b->base, MIN(new_allocated, b->allocated));
219 b->source = OFPBUF_MALLOC;
229 b->allocated = new_allocated;
230 ofpbuf_rebase__(b, new_base);
233 /* Ensures that 'b' has room for at least 'size' bytes at its tail end,
234 * reallocating and copying its data if necessary. Its headroom, if any, is
237 ofpbuf_prealloc_tailroom(struct ofpbuf *b, size_t size)
239 if (size > ofpbuf_tailroom(b)) {
240 ofpbuf_resize_tailroom__(b, MAX(size, 64));
245 ofpbuf_prealloc_headroom(struct ofpbuf *b, size_t size)
247 assert(size <= ofpbuf_headroom(b));
250 /* Trims the size of 'b' to fit its actual content, reducing its tailroom to
251 * 0. Its headroom, if any, is preserved.
253 * Buffers not obtained from malloc() are not resized, since that wouldn't save
256 ofpbuf_trim(struct ofpbuf *b)
258 if (b->source == OFPBUF_MALLOC && ofpbuf_tailroom(b) > 0) {
259 ofpbuf_resize_tailroom__(b, 0);
263 /* Appends 'size' bytes of data to the tail end of 'b', reallocating and
264 * copying its data if necessary. Returns a pointer to the first byte of the
265 * new data, which is left uninitialized. */
267 ofpbuf_put_uninit(struct ofpbuf *b, size_t size)
270 ofpbuf_prealloc_tailroom(b, size);
276 /* Appends 'size' zeroed bytes to the tail end of 'b'. Data in 'b' is
277 * reallocated and copied if necessary. Returns a pointer to the first byte of
278 * the data's location in the ofpbuf. */
280 ofpbuf_put_zeros(struct ofpbuf *b, size_t size)
282 void *dst = ofpbuf_put_uninit(b, size);
283 memset(dst, 0, size);
287 /* Appends the 'size' bytes of data in 'p' to the tail end of 'b'. Data in 'b'
288 * is reallocated and copied if necessary. Returns a pointer to the first
289 * byte of the data's location in the ofpbuf. */
291 ofpbuf_put(struct ofpbuf *b, const void *p, size_t size)
293 void *dst = ofpbuf_put_uninit(b, size);
294 memcpy(dst, p, size);
298 /* Parses as many pairs of hex digits as possible (possibly separated by
299 * spaces) from the beginning of 's', appending bytes for their values to 'b'.
300 * Returns the first character of 's' that is not the first of a pair of hex
301 * digits. If 'n' is nonnull, stores the number of bytes added to 'b' in
304 ofpbuf_put_hex(struct ofpbuf *b, const char *s, size_t *n)
306 size_t initial_size = b->size;
312 byte = hexits_value(s, 2, &ok);
315 *n = b->size - initial_size;
320 ofpbuf_put(b, &byte, 1);
325 /* Reserves 'size' bytes of headroom so that they can be later allocated with
326 * ofpbuf_push_uninit() without reallocating the ofpbuf. */
328 ofpbuf_reserve(struct ofpbuf *b, size_t size)
331 ofpbuf_prealloc_tailroom(b, size);
332 b->data = (char*)b->data + size;
336 ofpbuf_push_uninit(struct ofpbuf *b, size_t size)
338 ofpbuf_prealloc_headroom(b, size);
339 b->data = (char*)b->data - size;
344 /* Prefixes 'size' zeroed bytes to the head end of 'b'. 'b' must have at least
345 * 'size' bytes of headroom. Returns a pointer to the first byte of the data's
346 * location in the ofpbuf. */
348 ofpbuf_push_zeros(struct ofpbuf *b, size_t size)
350 void *dst = ofpbuf_push_uninit(b, size);
351 memset(dst, 0, size);
356 ofpbuf_push(struct ofpbuf *b, const void *p, size_t size)
358 void *dst = ofpbuf_push_uninit(b, size);
359 memcpy(dst, p, size);
363 /* If 'b' contains at least 'offset + size' bytes of data, returns a pointer to
364 * byte 'offset'. Otherwise, returns a null pointer. */
366 ofpbuf_at(const struct ofpbuf *b, size_t offset, size_t size)
368 return offset + size <= b->size ? (char *) b->data + offset : NULL;
371 /* Returns a pointer to byte 'offset' in 'b', which must contain at least
372 * 'offset + size' bytes of data. */
374 ofpbuf_at_assert(const struct ofpbuf *b, size_t offset, size_t size)
376 assert(offset + size <= b->size);
377 return ((char *) b->data) + offset;
380 /* Returns the byte following the last byte of data in use in 'b'. */
382 ofpbuf_tail(const struct ofpbuf *b)
384 return (char *) b->data + b->size;
387 /* Returns the byte following the last byte allocated for use (but not
388 * necessarily in use) by 'b'. */
390 ofpbuf_end(const struct ofpbuf *b)
392 return (char *) b->base + b->allocated;
395 /* Clears any data from 'b'. */
397 ofpbuf_clear(struct ofpbuf *b)
403 /* Removes 'size' bytes from the head end of 'b', which must contain at least
404 * 'size' bytes of data. Returns the first byte of data removed. */
406 ofpbuf_pull(struct ofpbuf *b, size_t size)
408 void *data = b->data;
409 assert(b->size >= size);
410 b->data = (char*)b->data + size;
415 /* If 'b' has at least 'size' bytes of data, removes that many bytes from the
416 * head end of 'b' and returns the first byte removed. Otherwise, returns a
417 * null pointer without modifying 'b'. */
419 ofpbuf_try_pull(struct ofpbuf *b, size_t size)
421 return b->size >= size ? ofpbuf_pull(b, size) : NULL;
424 /* Returns a string that describes some of 'b''s metadata plus a hex dump of up
425 * to 'maxbytes' from the start of the buffer. */
427 ofpbuf_to_string(const struct ofpbuf *b, size_t maxbytes)
432 ds_put_format(&s, "size=%zu, allocated=%zu, head=%zu, tail=%zu\n",
433 b->size, b->allocated,
434 ofpbuf_headroom(b), ofpbuf_tailroom(b));
435 ds_put_hex_dump(&s, b->data, MIN(b->size, maxbytes), 0, false);
439 /* Removes each of the "struct ofpbuf"s on 'list' from the list and frees
442 ofpbuf_list_delete(struct list *list)
444 struct ofpbuf *b, *next;
446 LIST_FOR_EACH_SAFE (b, next, list_node, list) {
447 list_remove(&b->list_node);