Commit 7b5e3afd authored by Bob Halley's avatar Bob Halley
Browse files

buffer.c

parent 928da6e9
#include <string.h>
#include <isc/assertions.h>
#include <isc/buffer.h>
#define VALID_BUFFER(b) ((b) != NULL)
void
isc_buffer_init(isc_buffer_t b, unsigned char *base, unsigned int length) {
/*
* Make 'b' refer to the 'length'-byte region starting at base.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(length > 0);
b->base = base;
b->length = length;
b->used = 0;
b->current = base;
}
void
isc_buffer_region(isc_buffer_t b, isc_region_t r) {
/*
* Make 'r' refer to the region of 'b'.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(r != NULL);
r->base = b->base;
r->length = b->length;
}
void
isc_buffer_used(isc_buffer_t b, isc_region_t r) {
/*
* Make 'r' refer to the used region of 'b'.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(r != NULL);
r->base = b->base;
r->length = b->used;
}
void
isc_buffer_available(isc_buffer_t b, isc_region_t r) {
/*
* Make 'r' refer to the available region of 'b'.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(r != NULL);
r->base = b->base + b->used;
r->length = b->length - b->used;
}
void
isc_buffer_add(isc_buffer_t b, unsigned int n) {
/*
* Increase the 'used' region of 'b' by 'n' bytes.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(b->used + n <= b->length);
b->used += n;
}
void
isc_buffer_subtract(isc_buffer_t b, unsigned int n) {
/*
* Decrease the 'used' region of 'b' by 'n' bytes.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(b->used >= n);
b->used -= n;
}
void
isc_buffer_clear(isc_buffer_t b) {
/*
* Make the used region empty.
*/
REQUIRE(VALID_BUFFER(b));
b->used = 0;
}
void
isc_buffer_consumed(isc_buffer_t b, isc_region_t r) {
/*
* Make 'r' refer to the consumed region of 'b'.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(r != NULL);
r->base = b->base;
r->length = (unsigned int)(b->current - b->base);
}
void
isc_buffer_remaining(isc_buffer_t b, isc_region_t r) {
/*
* Make 'r' refer to the remaining region of 'b'.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(r != NULL);
r->base = b->current;
r->length = (unsigned int)((b->base + b->used) - b->current);
}
void
isc_buffer_first(isc_buffer_t b) {
/*
* Make the consumed region empty.
*/
REQUIRE(VALID_BUFFER(b));
b->current = b->base;
}
void
isc_buffer_forward(isc_buffer_t b, unsigned int n) {
/*
* Decrease the 'used' region of 'b' by 'n' bytes.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(b->current + n <= b->base + b->used);
b->current += n;
}
void
isc_buffer_back(isc_buffer_t b, unsigned int n) {
/*
* Decrease the 'consumed' region of 'b' by 'n' bytes.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(b->base + n <= b->current);
b->current -= n;
}
void
isc_buffer_compact(isc_buffer_t b) {
unsigned int length;
/*
* Compact the used region by moving the remaining region so it occurs
* at the start of the buffer. The used region is shrunk by the size
* of the consumed region, and the consumed region is then made empty.
*/
REQUIRE(VALID_BUFFER(b));
length = (unsigned int)((b->base + b->used) - b->current);
(void)memmove(b->base, b->current, length);
b->current = b->base;
b->used = length;
}
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