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- jessie 1:9.9.5.dfsg-9+deb8u15
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LWRES_BUFFER(3) | BIND9 | LWRES_BUFFER(3) |
NAME¶
lwres_buffer_init, lwres_buffer_invalidate, lwres_buffer_add, lwres_buffer_subtract, lwres_buffer_clear, lwres_buffer_first, lwres_buffer_forward, lwres_buffer_back, lwres_buffer_getuint8, lwres_buffer_putuint8, lwres_buffer_getuint16, lwres_buffer_putuint16, lwres_buffer_getuint32, lwres_buffer_putuint32, lwres_buffer_putmem, lwres_buffer_getmem - lightweight resolver buffer managementSYNOPSIS¶
#include <lwres/lwbuffer.h>
void
lwres_buffer_init(lwres_buffer_t *b,
void *base,
unsigned int length);
void
lwres_buffer_invalidate(lwres_buffer_t *b);
void lwres_buffer_add(lwres_buffer_t *b,
unsigned int n);
void
lwres_buffer_subtract(lwres_buffer_t *b,
unsigned int n);
void
lwres_buffer_clear(lwres_buffer_t *b);
void
lwres_buffer_first(lwres_buffer_t *b);
void
lwres_buffer_forward(lwres_buffer_t *b,
unsigned int n);
void
lwres_buffer_back(lwres_buffer_t *b,
unsigned int n);
lwres_uint8_t
lwres_buffer_getuint8(lwres_buffer_t *b);
void
lwres_buffer_putuint8(lwres_buffer_t *b,
lwres_uint8_t val);
lwres_uint16_t
lwres_buffer_getuint16(lwres_buffer_t *b);
void
lwres_buffer_putuint16(lwres_buffer_t *b,
lwres_uint16_t val);
lwres_uint32_t
lwres_buffer_getuint32(lwres_buffer_t *b);
void
lwres_buffer_putuint32(lwres_buffer_t *b,
lwres_uint32_t val);
void
lwres_buffer_putmem(lwres_buffer_t *b,
const unsigned char *base,
unsigned int length);
void
lwres_buffer_getmem(lwres_buffer_t *b,
unsigned char *base,
unsigned int length);
DESCRIPTION¶
These functions provide bounds checked access to a region of memory where data is being read or written. They are based on, and similar to, the isc_buffer_ functions in the ISC library. A buffer is a region of memory, together with a set of related subregions. 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. Initially, the active region is empty. If the current offset advances beyond the chosen offset, the active region will also be empty./------------entire length---------------\\ /----- 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.
COPYRIGHT¶
Copyright © 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")June 30, 2000 | BIND9 |