]>
git.proxmox.com Git - ovs.git/blob - lib/ofpbuf.c
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
->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. 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
->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 /* Appends 'size' bytes of data to the tail end of 'b', reallocating and
363 * copying its data if necessary. Returns a pointer to the first byte of the
364 * new data, which is left uninitialized. */
366 ofpbuf_put_uninit(struct ofpbuf
*b
, size_t size
)
369 ofpbuf_prealloc_tailroom(b
, size
);
375 /* Appends 'size' zeroed bytes to the tail end of 'b'. Data in 'b' is
376 * reallocated and copied if necessary. Returns a pointer to the first byte of
377 * the data's location in the ofpbuf. */
379 ofpbuf_put_zeros(struct ofpbuf
*b
, size_t size
)
381 void *dst
= ofpbuf_put_uninit(b
, size
);
382 memset(dst
, 0, size
);
386 /* Appends the 'size' bytes of data in 'p' to the tail end of 'b'. Data in 'b'
387 * is reallocated and copied if necessary. Returns a pointer to the first
388 * byte of the data's location in the ofpbuf. */
390 ofpbuf_put(struct ofpbuf
*b
, const void *p
, size_t size
)
392 void *dst
= ofpbuf_put_uninit(b
, size
);
393 memcpy(dst
, p
, size
);
397 /* Parses as many pairs of hex digits as possible (possibly separated by
398 * spaces) from the beginning of 's', appending bytes for their values to 'b'.
399 * Returns the first character of 's' that is not the first of a pair of hex
400 * digits. If 'n' is nonnull, stores the number of bytes added to 'b' in
403 ofpbuf_put_hex(struct ofpbuf
*b
, const char *s
, size_t *n
)
405 size_t initial_size
= b
->size
;
411 byte
= hexits_value(s
, 2, &ok
);
414 *n
= b
->size
- initial_size
;
416 return CONST_CAST(char *, s
);
419 ofpbuf_put(b
, &byte
, 1);
424 /* Reserves 'size' bytes of headroom so that they can be later allocated with
425 * ofpbuf_push_uninit() without reallocating the ofpbuf. */
427 ofpbuf_reserve(struct ofpbuf
*b
, size_t size
)
429 ovs_assert(!b
->size
);
430 ofpbuf_prealloc_tailroom(b
, size
);
431 b
->data
= (char*)b
->data
+ size
;
434 /* Prefixes 'size' bytes to the head end of 'b', reallocating and copying its
435 * data if necessary. Returns a pointer to the first byte of the data's
436 * location in the ofpbuf. The new data is left uninitialized. */
438 ofpbuf_push_uninit(struct ofpbuf
*b
, size_t size
)
440 ofpbuf_prealloc_headroom(b
, size
);
441 b
->data
= (char*)b
->data
- size
;
446 /* Prefixes 'size' zeroed bytes to the head end of 'b', reallocating and
447 * copying its data if necessary. Returns a pointer to the first byte of the
448 * data's location in the ofpbuf. */
450 ofpbuf_push_zeros(struct ofpbuf
*b
, size_t size
)
452 void *dst
= ofpbuf_push_uninit(b
, size
);
453 memset(dst
, 0, size
);
457 /* Copies the 'size' bytes starting at 'p' to the head end of 'b', reallocating
458 * and copying its data if necessary. Returns a pointer to the first byte of
459 * the data's location in the ofpbuf. */
461 ofpbuf_push(struct ofpbuf
*b
, const void *p
, size_t size
)
463 void *dst
= ofpbuf_push_uninit(b
, size
);
464 memcpy(dst
, p
, size
);
468 /* If 'b' contains at least 'offset + size' bytes of data, returns a pointer to
469 * byte 'offset'. Otherwise, returns a null pointer. */
471 ofpbuf_at(const struct ofpbuf
*b
, size_t offset
, size_t size
)
473 return offset
+ size
<= b
->size
? (char *) b
->data
+ offset
: NULL
;
476 /* Returns a pointer to byte 'offset' in 'b', which must contain at least
477 * 'offset + size' bytes of data. */
479 ofpbuf_at_assert(const struct ofpbuf
*b
, size_t offset
, size_t size
)
481 ovs_assert(offset
+ size
<= b
->size
);
482 return ((char *) b
->data
) + offset
;
485 /* Returns the byte following the last byte of data in use in 'b'. */
487 ofpbuf_tail(const struct ofpbuf
*b
)
489 return (char *) b
->data
+ b
->size
;
492 /* Returns the byte following the last byte allocated for use (but not
493 * necessarily in use) by 'b'. */
495 ofpbuf_end(const struct ofpbuf
*b
)
497 return (char *) b
->base
+ b
->allocated
;
500 /* Clears any data from 'b'. */
502 ofpbuf_clear(struct ofpbuf
*b
)
508 /* Removes 'size' bytes from the head end of 'b', which must contain at least
509 * 'size' bytes of data. Returns the first byte of data removed. */
511 ofpbuf_pull(struct ofpbuf
*b
, size_t size
)
513 void *data
= b
->data
;
514 ovs_assert(b
->size
>= size
);
515 b
->data
= (char*)b
->data
+ size
;
520 /* If 'b' has at least 'size' bytes of data, removes that many bytes from the
521 * head end of 'b' and returns the first byte removed. Otherwise, returns a
522 * null pointer without modifying 'b'. */
524 ofpbuf_try_pull(struct ofpbuf
*b
, size_t size
)
526 return b
->size
>= size
? ofpbuf_pull(b
, size
) : NULL
;
529 /* Returns the data in 'b' as a block of malloc()'d memory and frees the buffer
530 * within 'b'. (If 'b' itself was dynamically allocated, e.g. with
531 * ofpbuf_new(), then it should still be freed with, e.g., ofpbuf_delete().) */
533 ofpbuf_steal_data(struct ofpbuf
*b
)
536 if (b
->source
== OFPBUF_MALLOC
&& b
->data
== b
->base
) {
539 p
= xmemdup(b
->data
, b
->size
);
540 if (b
->source
== OFPBUF_MALLOC
) {
544 b
->base
= b
->data
= NULL
;
548 /* Returns a string that describes some of 'b''s metadata plus a hex dump of up
549 * to 'maxbytes' from the start of the buffer. */
551 ofpbuf_to_string(const struct ofpbuf
*b
, size_t maxbytes
)
556 ds_put_format(&s
, "size=%zu, allocated=%zu, head=%zu, tail=%zu\n",
557 b
->size
, b
->allocated
,
558 ofpbuf_headroom(b
), ofpbuf_tailroom(b
));
559 ds_put_hex_dump(&s
, b
->data
, MIN(b
->size
, maxbytes
), 0, false);
563 /* Removes each of the "struct ofpbuf"s on 'list' from the list and frees
566 ofpbuf_list_delete(struct list
*list
)
568 struct ofpbuf
*b
, *next
;
570 LIST_FOR_EACH_SAFE (b
, next
, list_node
, list
) {
571 list_remove(&b
->list_node
);