2 * Copyright (C) 2004 Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1998-2002 Internet Software Consortium.
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
18 /* $Id: buffer.h,v 1.39.12.2 2004/03/08 09:04:51 marka Exp $ */
21 #define ISC_BUFFER_H 1
30 * A buffer is a region of memory, together with a set of related subregions.
31 * Buffers are used for parsing and I/O operations.
33 * The 'used region' and the 'available' region are disjoint, and their
34 * union is the buffer's region. The used region extends from the beginning
35 * of the buffer region to the last used byte. The available region
36 * extends from one byte greater than the last used byte to the end of the
37 * buffer's region. The size of the used region can be changed using various
38 * buffer commands. Initially, the used region is empty.
40 * The used region is further subdivided into two disjoint regions: the
41 * 'consumed region' and the 'remaining region'. The union of these two
42 * regions is the used region. The consumed region extends from the beginning
43 * of the used region to the byte before the 'current' offset (if any). The
44 * 'remaining' region the current pointer to the end of the used
45 * region. The size of the consumed region can be changed using various
46 * buffer commands. Initially, the consumed region is empty.
48 * The 'active region' is an (optional) subregion of the remaining region.
49 * It extends from the current offset to an offset in the remaining region
50 * that is selected with isc_buffer_setactive(). Initially, the active region
51 * is empty. If the current offset advances beyond the chosen offset, the
52 * active region will also be empty.
54 * /------------entire length---------------\
55 * /----- used region -----\/-- available --\
56 * +----------------------------------------+
57 * | consumed | remaining | |
58 * +----------------------------------------+
61 * a == base of buffer.
62 * b == current pointer. Can be anywhere between a and d.
63 * c == active pointer. Meaningful between b and d.
65 * e == length of buffer.
67 * a-e == entire length of buffer.
69 * a-b == consumed region.
70 * b-d == remaining region.
71 * b-c == optional active region.
73 * The following invariants are maintained by all routines:
77 * base is a valid pointer to length bytes of memory
81 * 0 <= current <= used
84 * (although active < current implies empty active region)
87 * Buffers have no synchronization. Clients must ensure exclusive
91 * No anticipated impact.
94 * Memory: 1 pointer + 6 unsigned integers per buffer.
97 * No anticipated impact.
107 #include <isc/lang.h>
108 #include <isc/magic.h>
109 #include <isc/types.h>
112 * To make many functions be inline macros (via #define) define this.
113 * If it is undefined, a function will be used.
115 #define ISC_BUFFER_USEINLINE
122 #define ISC_BUFFER_MAGIC 0x42756621U /* Buf!. */
123 #define ISC_BUFFER_VALID(b) ISC_MAGIC_VALID(b, ISC_BUFFER_MAGIC)
126 * The following macros MUST be used only on valid buffers. It is the
127 * caller's responsibility to ensure this by using the ISC_BUFFER_VALID
128 * check above, or by calling another isc_buffer_*() function (rather than
133 * Fundamental buffer elements. (A through E in the introductory comment.)
135 #define isc_buffer_base(b) ((void *)(b)->base) /*a*/
136 #define isc_buffer_current(b) \
137 ((void *)((unsigned char *)(b)->base + (b)->current)) /*b*/
138 #define isc_buffer_active(b) \
139 ((void *)((unsigned char *)(b)->base + (b)->active)) /*c*/
140 #define isc_buffer_used(b) \
141 ((void *)((unsigned char *)(b)->base + (b)->used)) /*d*/
142 #define isc_buffer_length(b) ((b)->length) /*e*/
145 * Derived lengths. (Described in the introductory comment.)
147 #define isc_buffer_usedlength(b) ((b)->used) /* d-a */
148 #define isc_buffer_consumedlength(b) ((b)->current) /* b-a */
149 #define isc_buffer_remaininglength(b) ((b)->used - (b)->current) /* d-b */
150 #define isc_buffer_activelength(b) ((b)->active - (b)->current) /* c-b */
151 #define isc_buffer_availablelength(b) ((b)->length - (b)->used) /* e-d */
154 * Note that the buffer structure is public. This is principally so buffer
155 * operations can be implemented using macros. Applications are strongly
156 * discouraged from directly manipulating the structure.
162 /* The following integers are byte offsets from 'base'. */
165 unsigned int current;
168 ISC_LINK(isc_buffer_t) link;
169 /* private internal elements */
178 isc_buffer_allocate(isc_mem_t *mctx, isc_buffer_t **dynbuffer,
179 unsigned int length);
181 * Allocate a dynamic linkable buffer which has "length" bytes in the
187 * "dynbuffer" is non-NULL, and "*dynbuffer" is NULL.
190 * ISC_R_SUCCESS - success
191 * ISC_R_NOMEMORY - no memory available
194 * Changing the buffer's length field is not permitted.
198 isc_buffer_free(isc_buffer_t **dynbuffer);
200 * Release resources allocated for a dynamic buffer.
203 * "dynbuffer" is not NULL.
205 * "*dynbuffer" is a valid dynamic buffer.
208 * "*dynbuffer" will be NULL on return, and all memory associated with
209 * the dynamic buffer is returned to the memory context used in
210 * isc_buffer_allocate().
214 isc__buffer_init(isc_buffer_t *b, const void *base, unsigned int length);
216 * Make 'b' refer to the 'length'-byte region starting at base.
222 * 'base' is a pointer to a sequence of 'length' bytes.
227 isc__buffer_invalidate(isc_buffer_t *b);
229 * Make 'b' an invalid buffer.
232 * 'b' is a valid buffer.
235 * If assertion checking is enabled, future attempts to use 'b' without
236 * calling isc_buffer_init() on it will cause an assertion failure.
240 isc__buffer_region(isc_buffer_t *b, isc_region_t *r);
242 * Make 'r' refer to the region of 'b'.
246 * 'b' is a valid buffer.
248 * 'r' points to a region structure.
252 isc__buffer_usedregion(isc_buffer_t *b, isc_region_t *r);
254 * Make 'r' refer to the used region of 'b'.
258 * 'b' is a valid buffer.
260 * 'r' points to a region structure.
264 isc__buffer_availableregion(isc_buffer_t *b, isc_region_t *r);
266 * Make 'r' refer to the available region of 'b'.
270 * 'b' is a valid buffer.
272 * 'r' points to a region structure.
276 isc__buffer_add(isc_buffer_t *b, unsigned int n);
278 * Increase the 'used' region of 'b' by 'n' bytes.
282 * 'b' is a valid buffer
289 isc__buffer_subtract(isc_buffer_t *b, unsigned int n);
291 * Decrease the 'used' region of 'b' by 'n' bytes.
295 * 'b' is a valid buffer
302 isc__buffer_clear(isc_buffer_t *b);
304 * Make the used region empty.
308 * 'b' is a valid buffer
317 isc__buffer_consumedregion(isc_buffer_t *b, isc_region_t *r);
319 * Make 'r' refer to the consumed region of 'b'.
323 * 'b' is a valid buffer.
325 * 'r' points to a region structure.
329 isc__buffer_remainingregion(isc_buffer_t *b, isc_region_t *r);
331 * Make 'r' refer to the remaining region of 'b'.
335 * 'b' is a valid buffer.
337 * 'r' points to a region structure.
341 isc__buffer_activeregion(isc_buffer_t *b, isc_region_t *r);
343 * Make 'r' refer to the active region of 'b'.
347 * 'b' is a valid buffer.
349 * 'r' points to a region structure.
353 isc__buffer_setactive(isc_buffer_t *b, unsigned int n);
355 * Sets the end of the active region 'n' bytes after current.
359 * 'b' is a valid buffer.
361 * current + n <= used
365 isc__buffer_first(isc_buffer_t *b);
367 * Make the consumed region empty.
371 * 'b' is a valid buffer
380 isc__buffer_forward(isc_buffer_t *b, unsigned int n);
382 * Increase the 'consumed' region of 'b' by 'n' bytes.
386 * 'b' is a valid buffer
388 * current + n <= used
393 isc__buffer_back(isc_buffer_t *b, unsigned int n);
395 * Decrease the 'consumed' region of 'b' by 'n' bytes.
399 * 'b' is a valid buffer
406 isc_buffer_compact(isc_buffer_t *b);
408 * Compact the used region by moving the remaining region so it occurs
409 * at the start of the buffer. The used region is shrunk by the size of
410 * the consumed region, and the consumed region is then made empty.
414 * 'b' is a valid buffer
420 * The size of the used region is now equal to the size of the remaining
421 * region (as it was before the call). The contents of the used region
422 * are those of the remaining region (as it was before the call).
426 isc_buffer_getuint8(isc_buffer_t *b);
428 * Read an unsigned 8-bit integer from 'b' and return it.
432 * 'b' is a valid buffer.
434 * The length of the available region of 'b' is at least 1.
438 * The current pointer in 'b' is advanced by 1.
442 * A 8-bit unsigned integer.
446 isc__buffer_putuint8(isc_buffer_t *b, isc_uint8_t val);
448 * Store an unsigned 8-bit integer from 'val' into 'b'.
451 * 'b' is a valid buffer.
453 * The length of the unused region of 'b' is at least 1.
456 * The used pointer in 'b' is advanced by 1.
460 isc_buffer_getuint16(isc_buffer_t *b);
462 * Read an unsigned 16-bit integer in network byte order from 'b', convert
463 * it to host byte order, and return it.
467 * 'b' is a valid buffer.
469 * The length of the available region of 'b' is at least 2.
473 * The current pointer in 'b' is advanced by 2.
477 * A 16-bit unsigned integer.
481 isc__buffer_putuint16(isc_buffer_t *b, isc_uint16_t val);
483 * Store an unsigned 16-bit integer in host byte order from 'val'
484 * into 'b' in network byte order.
487 * 'b' is a valid buffer.
489 * The length of the unused region of 'b' is at least 2.
492 * The used pointer in 'b' is advanced by 2.
496 isc_buffer_getuint32(isc_buffer_t *b);
498 * Read an unsigned 32-bit integer in network byte order from 'b', convert
499 * it to host byte order, and return it.
503 * 'b' is a valid buffer.
505 * The length of the available region of 'b' is at least 4.
509 * The current pointer in 'b' is advanced by 4.
513 * A 32-bit unsigned integer.
517 isc__buffer_putuint32(isc_buffer_t *b, isc_uint32_t val);
519 * Store an unsigned 32-bit integer in host byte order from 'val'
520 * into 'b' in network byte order.
523 * 'b' is a valid buffer.
525 * The length of the unused region of 'b' is at least 4.
528 * The used pointer in 'b' is advanced by 4.
532 isc__buffer_putmem(isc_buffer_t *b, const unsigned char *base,
533 unsigned int length);
535 * Copy 'length' bytes of memory at 'base' into 'b'.
538 * 'b' is a valid buffer.
540 * 'base' points to 'length' bytes of valid memory.
545 isc__buffer_putstr(isc_buffer_t *b, const char *source);
547 * Copy 'source' into 'b', not including terminating NUL.
550 * 'b' is a valid buffer.
552 * 'source' to be a valid NULL terminated string.
554 * strlen(source) <= isc_buffer_available(b)
558 isc_buffer_copyregion(isc_buffer_t *b, const isc_region_t *r);
560 * Copy the contents of 'r' into 'b'.
563 * 'b' is a valid buffer.
565 * 'r' is a valid region.
570 * ISC_R_NOSPACE The available region of 'b' is not
577 * Inline macro versions of the functions. These should never be called
578 * directly by an application, but will be used by the functions within
579 * buffer.c. The callers should always use "isc_buffer_*()" names, never
580 * ones beginning with "isc__"
584 * XXXDCL Something more could be done with initializing buffers that
585 * point to const data. For example, a new function, isc_buffer_initconst,
586 * could be used, and a new boolean flag in the buffer structure could
587 * indicate whether the buffer was initialized with that function.
588 * (isc_bufer_init itself would be reprototyped to *not* have its "base"
589 * parameter be const.) Then if the boolean were true, the isc_buffer_put*
590 * functions could assert a contractual requirement for a non-const buffer.
591 * One drawback is that the isc_buffer_* functions (macros) that return
592 * pointers would still need to return non-const pointers to avoid compiler
593 * warnings, so it would be up to code that uses them to have to deal
594 * with the possibility that the buffer was initialized as const --
595 * a problem that they *already* have to deal with but have absolutely
596 * no ability to. With a new isc_buffer_isconst() function returning
597 * true/false, they could at least assert a contractual requirement for
598 * non-const buffers when needed.
600 #define ISC__BUFFER_INIT(_b, _base, _length) \
603 const void * konst; \
606 _u.konst = (_base); \
607 (_b)->base = _u.var; \
608 (_b)->length = (_length); \
613 ISC_LINK_INIT(_b, link); \
614 (_b)->magic = ISC_BUFFER_MAGIC; \
617 #define ISC__BUFFER_INVALIDATE(_b) \
627 #define ISC__BUFFER_REGION(_b, _r) \
629 (_r)->base = (_b)->base; \
630 (_r)->length = (_b)->length; \
633 #define ISC__BUFFER_USEDREGION(_b, _r) \
635 (_r)->base = (_b)->base; \
636 (_r)->length = (_b)->used; \
639 #define ISC__BUFFER_AVAILABLEREGION(_b, _r) \
641 (_r)->base = isc_buffer_used(_b); \
642 (_r)->length = isc_buffer_availablelength(_b); \
645 #define ISC__BUFFER_ADD(_b, _n) \
647 (_b)->used += (_n); \
650 #define ISC__BUFFER_SUBTRACT(_b, _n) \
652 (_b)->used -= (_n); \
653 if ((_b)->current > (_b)->used) \
654 (_b)->current = (_b)->used; \
655 if ((_b)->active > (_b)->used) \
656 (_b)->active = (_b)->used; \
659 #define ISC__BUFFER_CLEAR(_b) \
666 #define ISC__BUFFER_CONSUMEDREGION(_b, _r) \
668 (_r)->base = (_b)->base; \
669 (_r)->length = (_b)->current; \
672 #define ISC__BUFFER_REMAININGREGION(_b, _r) \
674 (_r)->base = isc_buffer_current(_b); \
675 (_r)->length = isc_buffer_remaininglength(_b); \
678 #define ISC__BUFFER_ACTIVEREGION(_b, _r) \
680 if ((_b)->current < (_b)->active) { \
681 (_r)->base = isc_buffer_current(_b); \
682 (_r)->length = isc_buffer_activelength(_b); \
689 #define ISC__BUFFER_SETACTIVE(_b, _n) \
691 (_b)->active = (_b)->current + (_n); \
694 #define ISC__BUFFER_FIRST(_b) \
699 #define ISC__BUFFER_FORWARD(_b, _n) \
701 (_b)->current += (_n); \
704 #define ISC__BUFFER_BACK(_b, _n) \
706 (_b)->current -= (_n); \
709 #define ISC__BUFFER_PUTMEM(_b, _base, _length) \
711 memcpy(isc_buffer_used(_b), (_base), (_length)); \
712 (_b)->used += (_length); \
715 #define ISC__BUFFER_PUTSTR(_b, _source) \
717 unsigned int _length; \
718 unsigned char *_cp; \
719 _length = strlen(_source); \
720 _cp = isc_buffer_used(_b); \
721 memcpy(_cp, (_source), _length); \
722 (_b)->used += (_length); \
725 #define ISC__BUFFER_PUTUINT8(_b, _val) \
727 unsigned char *_cp; \
728 isc_uint8_t _val2 = (_val); \
729 _cp = isc_buffer_used(_b); \
731 _cp[0] = _val2 & 0x00ff; \
734 #define ISC__BUFFER_PUTUINT16(_b, _val) \
736 unsigned char *_cp; \
737 isc_uint16_t _val2 = (_val); \
738 _cp = isc_buffer_used(_b); \
740 _cp[0] = (unsigned char)((_val2 & 0xff00U) >> 8); \
741 _cp[1] = (unsigned char)(_val2 & 0x00ffU); \
744 #define ISC__BUFFER_PUTUINT32(_b, _val) \
746 unsigned char *_cp; \
747 isc_uint32_t _val2 = (_val); \
748 _cp = isc_buffer_used(_b); \
750 _cp[0] = (unsigned char)((_val2 & 0xff000000) >> 24); \
751 _cp[1] = (unsigned char)((_val2 & 0x00ff0000) >> 16); \
752 _cp[2] = (unsigned char)((_val2 & 0x0000ff00) >> 8); \
753 _cp[3] = (unsigned char)((_val2 & 0x000000ff)); \
756 #if defined(ISC_BUFFER_USEINLINE)
757 #define isc_buffer_init ISC__BUFFER_INIT
758 #define isc_buffer_invalidate ISC__BUFFER_INVALIDATE
759 #define isc_buffer_region ISC__BUFFER_REGION
760 #define isc_buffer_usedregion ISC__BUFFER_USEDREGION
761 #define isc_buffer_availableregion ISC__BUFFER_AVAILABLEREGION
762 #define isc_buffer_add ISC__BUFFER_ADD
763 #define isc_buffer_subtract ISC__BUFFER_SUBTRACT
764 #define isc_buffer_clear ISC__BUFFER_CLEAR
765 #define isc_buffer_consumedregion ISC__BUFFER_CONSUMEDREGION
766 #define isc_buffer_remainingregion ISC__BUFFER_REMAININGREGION
767 #define isc_buffer_activeregion ISC__BUFFER_ACTIVEREGION
768 #define isc_buffer_setactive ISC__BUFFER_SETACTIVE
769 #define isc_buffer_first ISC__BUFFER_FIRST
770 #define isc_buffer_forward ISC__BUFFER_FORWARD
771 #define isc_buffer_back ISC__BUFFER_BACK
772 #define isc_buffer_putmem ISC__BUFFER_PUTMEM
773 #define isc_buffer_putstr ISC__BUFFER_PUTSTR
774 #define isc_buffer_putuint8 ISC__BUFFER_PUTUINT8
775 #define isc_buffer_putuint16 ISC__BUFFER_PUTUINT16
776 #define isc_buffer_putuint32 ISC__BUFFER_PUTUINT32
778 #define isc_buffer_init isc__buffer_init
779 #define isc_buffer_invalidate isc__buffer_invalidate
780 #define isc_buffer_region isc__buffer_region
781 #define isc_buffer_usedregion isc__buffer_usedregion
782 #define isc_buffer_availableregion isc__buffer_availableregion
783 #define isc_buffer_add isc__buffer_add
784 #define isc_buffer_subtract isc__buffer_subtract
785 #define isc_buffer_clear isc__buffer_clear
786 #define isc_buffer_consumedregion isc__buffer_consumedregion
787 #define isc_buffer_remainingregion isc__buffer_remainingregion
788 #define isc_buffer_activeregion isc__buffer_activeregion
789 #define isc_buffer_setactive isc__buffer_setactive
790 #define isc_buffer_first isc__buffer_first
791 #define isc_buffer_forward isc__buffer_forward
792 #define isc_buffer_back isc__buffer_back
793 #define isc_buffer_putmem isc__buffer_putmem
794 #define isc_buffer_putstr isc__buffer_putstr
795 #define isc_buffer_putuint8 isc__buffer_putuint8
796 #define isc_buffer_putuint16 isc__buffer_putuint16
797 #define isc_buffer_putuint32 isc__buffer_putuint32
800 #endif /* ISC_BUFFER_H */