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"
25 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
26 * memory starting at 'base'.
28 * 'base' should ordinarily be the first byte of a region obtained from
29 * malloc(), but in circumstances where it can be guaranteed that 'b' will
30 * never need to be expanded or freed, it can be a pointer into arbitrary
33 ofpbuf_use(struct ofpbuf *b, void *base, size_t allocated)
35 b->base = b->data = base;
36 b->allocated = allocated;
38 b->l2 = b->l3 = b->l4 = b->l7 = NULL;
39 list_poison(&b->list_node);
43 /* Initializes 'b' as an ofpbuf whose data starts at 'data' and continues for
44 * 'size' bytes. This is appropriate for an ofpbuf that will be used to
45 * inspect existing data, without moving it around or reallocating it, and
46 * generally without modifying it at all. */
48 ofpbuf_use_const(struct ofpbuf *b, const void *data, size_t size)
50 ofpbuf_use(b, (void *) data, size);
54 /* Initializes 'b' as an empty ofpbuf with an initial capacity of 'size'
57 ofpbuf_init(struct ofpbuf *b, size_t size)
59 ofpbuf_use(b, size ? xmalloc(size) : NULL, size);
62 /* Frees memory that 'b' points to. */
64 ofpbuf_uninit(struct ofpbuf *b)
71 /* Frees memory that 'b' points to and allocates a new ofpbuf */
73 ofpbuf_reinit(struct ofpbuf *b, size_t size)
79 /* Creates and returns a new ofpbuf with an initial capacity of 'size'
82 ofpbuf_new(size_t size)
84 struct ofpbuf *b = xmalloc(sizeof *b);
89 /* Creates and returns a new ofpbuf with an initial capacity of 'size +
90 * headroom' bytes, reserving the first 'headroom' bytes as headroom. */
92 ofpbuf_new_with_headroom(size_t size, size_t headroom)
94 struct ofpbuf *b = ofpbuf_new(size + headroom);
95 ofpbuf_reserve(b, headroom);
100 ofpbuf_clone(const struct ofpbuf *buffer)
102 return ofpbuf_clone_data(buffer->data, buffer->size);
105 /* Creates and returns a new ofpbuf whose data are copied from 'buffer'. The
106 * returned ofpbuf will additionally have 'headroom' bytes of headroom. */
108 ofpbuf_clone_with_headroom(const struct ofpbuf *buffer, size_t headroom)
110 struct ofpbuf *b = ofpbuf_new_with_headroom(buffer->size, headroom);
111 ofpbuf_put(b, buffer->data, buffer->size);
116 ofpbuf_clone_data(const void *data, size_t size)
118 struct ofpbuf *b = ofpbuf_new(size);
119 ofpbuf_put(b, data, size);
123 /* Frees memory that 'b' points to, as well as 'b' itself. */
125 ofpbuf_delete(struct ofpbuf *b)
133 /* Returns the number of bytes of headroom in 'b', that is, the number of bytes
134 * of unused space in ofpbuf 'b' before the data that is in use. (Most
135 * commonly, the data in a ofpbuf is at its beginning, and thus the ofpbuf's
138 ofpbuf_headroom(const struct ofpbuf *b)
140 return (char*)b->data - (char*)b->base;
143 /* Returns the number of bytes that may be appended to the tail end of ofpbuf
144 * 'b' before the ofpbuf must be reallocated. */
146 ofpbuf_tailroom(const struct ofpbuf *b)
148 return (char*)ofpbuf_end(b) - (char*)ofpbuf_tail(b);
151 /* Changes 'b->base' to 'new_base' and adjusts all of 'b''s internal pointers
152 * to reflect the change. */
154 ofpbuf_rebase__(struct ofpbuf *b, void *new_base)
156 if (b->base != new_base) {
157 uintptr_t base_delta = (char*)new_base - (char*)b->base;
159 b->data = (char*)b->data + base_delta;
161 b->l2 = (char*)b->l2 + base_delta;
164 b->l3 = (char*)b->l3 + base_delta;
167 b->l4 = (char*)b->l4 + base_delta;
170 b->l7 = (char*)b->l7 + base_delta;
175 /* Reallocates 'b' so that it has exactly 'new_tailroom' bytes of tailroom. */
177 ofpbuf_resize_tailroom__(struct ofpbuf *b, size_t new_tailroom)
179 b->allocated = ofpbuf_headroom(b) + b->size + new_tailroom;
180 ofpbuf_rebase__(b, xrealloc(b->base, b->allocated));
183 /* Ensures that 'b' has room for at least 'size' bytes at its tail end,
184 * reallocating and copying its data if necessary. Its headroom, if any, is
187 ofpbuf_prealloc_tailroom(struct ofpbuf *b, size_t size)
189 if (size > ofpbuf_tailroom(b)) {
190 ofpbuf_resize_tailroom__(b, MAX(size, 64));
195 ofpbuf_prealloc_headroom(struct ofpbuf *b, size_t size)
197 assert(size <= ofpbuf_headroom(b));
200 /* Trims the size of 'b' to fit its actual content, reducing its tailroom to
201 * 0. Its headroom, if any, is preserved. */
203 ofpbuf_trim(struct ofpbuf *b)
205 if (ofpbuf_tailroom(b) > 0) {
206 ofpbuf_resize_tailroom__(b, 0);
210 /* Appends 'size' bytes of data to the tail end of 'b', reallocating and
211 * copying its data if necessary. Returns a pointer to the first byte of the
212 * new data, which is left uninitialized. */
214 ofpbuf_put_uninit(struct ofpbuf *b, size_t size)
217 ofpbuf_prealloc_tailroom(b, size);
223 /* Appends 'size' zeroed bytes to the tail end of 'b'. Data in 'b' is
224 * reallocated and copied if necessary. Returns a pointer to the first byte of
225 * the data's location in the ofpbuf. */
227 ofpbuf_put_zeros(struct ofpbuf *b, size_t size)
229 void *dst = ofpbuf_put_uninit(b, size);
230 memset(dst, 0, size);
234 /* Appends the 'size' bytes of data in 'p' to the tail end of 'b'. Data in 'b'
235 * is reallocated and copied if necessary. Returns a pointer to the first
236 * byte of the data's location in the ofpbuf. */
238 ofpbuf_put(struct ofpbuf *b, const void *p, size_t size)
240 void *dst = ofpbuf_put_uninit(b, size);
241 memcpy(dst, p, size);
245 /* Reserves 'size' bytes of headroom so that they can be later allocated with
246 * ofpbuf_push_uninit() without reallocating the ofpbuf. */
248 ofpbuf_reserve(struct ofpbuf *b, size_t size)
251 ofpbuf_prealloc_tailroom(b, size);
252 b->data = (char*)b->data + size;
256 ofpbuf_push_uninit(struct ofpbuf *b, size_t size)
258 ofpbuf_prealloc_headroom(b, size);
259 b->data = (char*)b->data - size;
264 /* Prefixes 'size' zeroed bytes to the head end of 'b'. 'b' must have at least
265 * 'size' bytes of headroom. Returns a pointer to the first byte of the data's
266 * location in the ofpbuf. */
268 ofpbuf_push_zeros(struct ofpbuf *b, size_t size)
270 void *dst = ofpbuf_push_uninit(b, size);
271 memset(dst, 0, size);
276 ofpbuf_push(struct ofpbuf *b, const void *p, size_t size)
278 void *dst = ofpbuf_push_uninit(b, size);
279 memcpy(dst, p, size);
283 /* If 'b' contains at least 'offset + size' bytes of data, returns a pointer to
284 * byte 'offset'. Otherwise, returns a null pointer. */
286 ofpbuf_at(const struct ofpbuf *b, size_t offset, size_t size)
288 return offset + size <= b->size ? (char *) b->data + offset : NULL;
291 /* Returns a pointer to byte 'offset' in 'b', which must contain at least
292 * 'offset + size' bytes of data. */
294 ofpbuf_at_assert(const struct ofpbuf *b, size_t offset, size_t size)
296 assert(offset + size <= b->size);
297 return ((char *) b->data) + offset;
300 /* Returns the byte following the last byte of data in use in 'b'. */
302 ofpbuf_tail(const struct ofpbuf *b)
304 return (char *) b->data + b->size;
307 /* Returns the byte following the last byte allocated for use (but not
308 * necessarily in use) by 'b'. */
310 ofpbuf_end(const struct ofpbuf *b)
312 return (char *) b->base + b->allocated;
315 /* Clears any data from 'b'. */
317 ofpbuf_clear(struct ofpbuf *b)
323 /* Removes 'size' bytes from the head end of 'b', which must contain at least
324 * 'size' bytes of data. Returns the first byte of data removed. */
326 ofpbuf_pull(struct ofpbuf *b, size_t size)
328 void *data = b->data;
329 assert(b->size >= size);
330 b->data = (char*)b->data + size;
335 /* If 'b' has at least 'size' bytes of data, removes that many bytes from the
336 * head end of 'b' and returns the first byte removed. Otherwise, returns a
337 * null pointer without modifying 'b'. */
339 ofpbuf_try_pull(struct ofpbuf *b, size_t size)
341 return b->size >= size ? ofpbuf_pull(b, size) : NULL;
344 /* Returns a string that describes some of 'b''s metadata plus a hex dump of up
345 * to 'maxbytes' from the start of the buffer. */
347 ofpbuf_to_string(const struct ofpbuf *b, size_t maxbytes)
352 ds_put_format(&s, "size=%zu, allocated=%zu, head=%zu, tail=%zu\n",
353 b->size, b->allocated,
354 ofpbuf_headroom(b), ofpbuf_tailroom(b));
355 ds_put_hex_dump(&s, b->data, MIN(b->size, maxbytes), 0, false);
359 /* Removes each of the "struct ofpbuf"s on 'list' from the list and frees
362 ofpbuf_list_delete(struct list *list)
364 struct ofpbuf *b, *next;
366 LIST_FOR_EACH_SAFE (b, next, list_node, list) {
367 list_remove(&b->list_node);