/contrib/bind9/lib/lwres/include/lwres/lwbuffer.h
https://bitbucket.org/freebsd/freebsd-head/ · C Header · 406 lines · 56 code · 35 blank · 315 comment · 3 complexity · de4fd9bbc41badc0d78922a975179928 MD5 · raw file
- /*
- * Copyright (C) 2004-2007 Internet Systems Consortium, Inc. ("ISC")
- * Copyright (C) 2000, 2001 Internet Software Consortium.
- *
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
- * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
- * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
- * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
- * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
- * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
- * PERFORMANCE OF THIS SOFTWARE.
- */
- /* $Id: lwbuffer.h,v 1.22 2007/06/19 23:47:23 tbox Exp $ */
- /*! \file lwres/lwbuffer.h
- *
- * A buffer is a region of memory, together with a set of related subregions.
- * Buffers are used for parsing and I/O operations.
- *
- * The 'used region' and the 'available' region are disjoint, and their
- * union is the buffer's region. The used region extends from the beginning
- * of the buffer region to the last used byte. The available region
- * extends from one byte greater than the last used byte to the end of the
- * buffer's region. The size of the used region can be changed using various
- * buffer commands. Initially, the used region is empty.
- *
- * The used region is further subdivided into two disjoint regions: the
- * 'consumed region' and the 'remaining region'. The union of these two
- * regions is the used region. The consumed region extends from the beginning
- * of the used region to the byte before the 'current' offset (if any). The
- * 'remaining' region the current pointer to the end of the used
- * region. The size of the consumed region can be changed using various
- * buffer commands. Initially, the consumed region is empty.
- *
- * The 'active region' is an (optional) subregion of the remaining region.
- * It extends from the current offset to an offset in the remaining region
- * that is selected with lwres_buffer_setactive(). Initially, the active
- * region is empty. If the current offset advances beyond the chosen offset,
- * the active region will also be empty.
- *
- * \verbatim
- * /----- used region -----\/-- available --\
- * +----------------------------------------+
- * | consumed | remaining | |
- * +----------------------------------------+
- * a b c d e
- *
- * a == base of buffer.
- * b == current pointer. Can be anywhere between a and d.
- * c == active pointer. Meaningful between b and d.
- * d == used pointer.
- * e == length of buffer.
- *
- * a-e == entire (length) of buffer.
- * a-d == used region.
- * a-b == consumed region.
- * b-d == remaining region.
- * b-c == optional active region.
- * \endverbatim
- *
- * The following invariants are maintained by all routines:
- *
- *\verbatim
- * length > 0
- *
- * base is a valid pointer to length bytes of memory
- *
- * 0 <= used <= length
- *
- * 0 <= current <= used
- *
- * 0 <= active <= used
- * (although active < current implies empty active region)
- *\endverbatim
- *
- * \li MP:
- * Buffers have no synchronization. Clients must ensure exclusive
- * access.
- *
- * \li Reliability:
- * No anticipated impact.
- *
- * \li Resources:
- * Memory: 1 pointer + 6 unsigned integers per buffer.
- *
- * \li Security:
- * No anticipated impact.
- *
- * \li Standards:
- * None.
- */
- #ifndef LWRES_LWBUFFER_H
- #define LWRES_LWBUFFER_H 1
- /***
- *** Imports
- ***/
- #include <lwres/lang.h>
- #include <lwres/int.h>
- LWRES_LANG_BEGINDECLS
- /***
- *** Magic numbers
- ***/
- #define LWRES_BUFFER_MAGIC 0x4275663fU /* Buf?. */
- #define LWRES_BUFFER_VALID(b) ((b) != NULL && \
- (b)->magic == LWRES_BUFFER_MAGIC)
- /*!
- * The following macros MUST be used only on valid buffers. It is the
- * caller's responsibility to ensure this by using the LWRES_BUFFER_VALID
- * check above, or by calling another lwres_buffer_*() function (rather than
- * another macro.)
- */
- /*!
- * Get the length of the used region of buffer "b"
- */
- #define LWRES_BUFFER_USEDCOUNT(b) ((b)->used)
- /*!
- * Get the length of the available region of buffer "b"
- */
- #define LWRES_BUFFER_AVAILABLECOUNT(b) ((b)->length - (b)->used)
- #define LWRES_BUFFER_REMAINING(b) ((b)->used - (b)->current)
- /*!
- * Note that the buffer structure is public. This is principally so buffer
- * operations can be implemented using macros. Applications are strongly
- * discouraged from directly manipulating the structure.
- */
- typedef struct lwres_buffer lwres_buffer_t;
- /*!
- * Buffer data structure
- */
- struct lwres_buffer {
- unsigned int magic;
- unsigned char *base;
- /* The following integers are byte offsets from 'base'. */
- unsigned int length;
- unsigned int used;
- unsigned int current;
- unsigned int active;
- };
- /***
- *** Functions
- ***/
- void
- lwres_buffer_init(lwres_buffer_t *b, void *base, unsigned int length);
- /**<
- * Make 'b' refer to the 'length'-byte region starting at base.
- *
- * Requires:
- *
- * 'length' > 0
- *
- * 'base' is a pointer to a sequence of 'length' bytes.
- *
- */
- void
- lwres_buffer_invalidate(lwres_buffer_t *b);
- /**<
- * Make 'b' an invalid buffer.
- *
- * Requires:
- * 'b' is a valid buffer.
- *
- * Ensures:
- * If assertion checking is enabled, future attempts to use 'b' without
- * calling lwres_buffer_init() on it will cause an assertion failure.
- */
- void
- lwres_buffer_add(lwres_buffer_t *b, unsigned int n);
- /**<
- * Increase the 'used' region of 'b' by 'n' bytes.
- *
- * Requires:
- *
- * 'b' is a valid buffer
- *
- * used + n <= length
- *
- */
- void
- lwres_buffer_subtract(lwres_buffer_t *b, unsigned int n);
- /**<
- * Decrease the 'used' region of 'b' by 'n' bytes.
- *
- * Requires:
- *
- * 'b' is a valid buffer
- *
- * used >= n
- *
- */
- void
- lwres_buffer_clear(lwres_buffer_t *b);
- /**<
- * Make the used region empty.
- *
- * Requires:
- *
- * 'b' is a valid buffer
- *
- * Ensures:
- *
- * used = 0
- *
- */
- void
- lwres_buffer_first(lwres_buffer_t *b);
- /**<
- * Make the consumed region empty.
- *
- * Requires:
- *
- * 'b' is a valid buffer
- *
- * Ensures:
- *
- * current == 0
- *
- */
- void
- lwres_buffer_forward(lwres_buffer_t *b, unsigned int n);
- /**<
- * Increase the 'consumed' region of 'b' by 'n' bytes.
- *
- * Requires:
- *
- * 'b' is a valid buffer
- *
- * current + n <= used
- *
- */
- void
- lwres_buffer_back(lwres_buffer_t *b, unsigned int n);
- /**<
- * Decrease the 'consumed' region of 'b' by 'n' bytes.
- *
- * Requires:
- *
- * 'b' is a valid buffer
- *
- * n <= current
- *
- */
- lwres_uint8_t
- lwres_buffer_getuint8(lwres_buffer_t *b);
- /**<
- * Read an unsigned 8-bit integer from 'b' and return it.
- *
- * Requires:
- *
- * 'b' is a valid buffer.
- *
- * The length of the available region of 'b' is at least 1.
- *
- * Ensures:
- *
- * The current pointer in 'b' is advanced by 1.
- *
- * Returns:
- *
- * A 8-bit unsigned integer.
- */
- void
- lwres_buffer_putuint8(lwres_buffer_t *b, lwres_uint8_t val);
- /**<
- * Store an unsigned 8-bit integer from 'val' into 'b'.
- *
- * Requires:
- * 'b' is a valid buffer.
- *
- * The length of the unused region of 'b' is at least 1.
- *
- * Ensures:
- * The used pointer in 'b' is advanced by 1.
- */
- lwres_uint16_t
- lwres_buffer_getuint16(lwres_buffer_t *b);
- /**<
- * Read an unsigned 16-bit integer in network byte order from 'b', convert
- * it to host byte order, and return it.
- *
- * Requires:
- *
- * 'b' is a valid buffer.
- *
- * The length of the available region of 'b' is at least 2.
- *
- * Ensures:
- *
- * The current pointer in 'b' is advanced by 2.
- *
- * Returns:
- *
- * A 16-bit unsigned integer.
- */
- void
- lwres_buffer_putuint16(lwres_buffer_t *b, lwres_uint16_t val);
- /**<
- * Store an unsigned 16-bit integer in host byte order from 'val'
- * into 'b' in network byte order.
- *
- * Requires:
- * 'b' is a valid buffer.
- *
- * The length of the unused region of 'b' is at least 2.
- *
- * Ensures:
- * The used pointer in 'b' is advanced by 2.
- */
- lwres_uint32_t
- lwres_buffer_getuint32(lwres_buffer_t *b);
- /**<
- * Read an unsigned 32-bit integer in network byte order from 'b', convert
- * it to host byte order, and return it.
- *
- * Requires:
- *
- * 'b' is a valid buffer.
- *
- * The length of the available region of 'b' is at least 2.
- *
- * Ensures:
- *
- * The current pointer in 'b' is advanced by 2.
- *
- * Returns:
- *
- * A 32-bit unsigned integer.
- */
- void
- lwres_buffer_putuint32(lwres_buffer_t *b, lwres_uint32_t val);
- /**<
- * Store an unsigned 32-bit integer in host byte order from 'val'
- * into 'b' in network byte order.
- *
- * Requires:
- * 'b' is a valid buffer.
- *
- * The length of the unused region of 'b' is at least 4.
- *
- * Ensures:
- * The used pointer in 'b' is advanced by 4.
- */
- void
- lwres_buffer_putmem(lwres_buffer_t *b, const unsigned char *base,
- unsigned int length);
- /**<
- * Copy 'length' bytes of memory at 'base' into 'b'.
- *
- * Requires:
- * 'b' is a valid buffer.
- *
- * 'base' points to 'length' bytes of valid memory.
- *
- */
- void
- lwres_buffer_getmem(lwres_buffer_t *b, unsigned char *base,
- unsigned int length);
- /**<
- * Copy 'length' bytes of memory from 'b' into 'base'.
- *
- * Requires:
- * 'b' is a valid buffer.
- *
- * 'base' points to at least 'length' bytes of valid memory.
- *
- * 'b' have at least 'length' bytes remaining.
- */
- LWRES_LANG_ENDDECLS
- #endif /* LWRES_LWBUFFER_H */