buffer.c revision 4556681e191b7c1654639895ce719d98f2822ee2
/*
* Copyright (C) 1998, 1999 Internet Software Consortium.
*
* Permission to use, copy, modify, and 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM 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.
*/
#include <config.h>
#include <string.h>
#include <isc/assertions.h>
#include <isc/buffer.h>
#define BUFFER_MAGIC 0x42756621U /* Buf!. */
#define VALID_BUFFER(b) ((b) != NULL && \
(b)->magic == BUFFER_MAGIC)
void
isc_buffer_init(isc_buffer_t *b, void *base, unsigned int length,
unsigned int type)
{
/*
* Make 'b' refer to the 'length'-byte region starting at base.
*/
REQUIRE(b != NULL);
b->magic = BUFFER_MAGIC;
b->type = type;
b->base = base;
b->length = length;
b->used = 0;
b->current = 0;
b->active = 0;
b->mctx = NULL;
ISC_LINK_INIT(b, link);
}
void
isc_buffer_invalidate(isc_buffer_t *b) {
/*
* Make 'b' an invalid buffer.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(!ISC_LINK_LINKED(b, link));
REQUIRE(b->mctx == NULL);
b->magic = 0;
b->type = 0;
b->base = NULL;
b->length = 0;
b->used = 0;
b->current = 0;
b->active = 0;
}
unsigned int
isc_buffer_type(isc_buffer_t *b) {
/*
* The type of 'b'.
*/
REQUIRE(VALID_BUFFER(b));
return (b->type);
}
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 = (unsigned char *)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;
if (b->current > b->used)
b->current = b->used;
if (b->active > b->used)
b->active = b->used;
}
void
isc_buffer_clear(isc_buffer_t *b) {
/*
* Make the used region empty.
*/
REQUIRE(VALID_BUFFER(b));
b->used = 0;
b->current = 0;
b->active = 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 = b->current;
}
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 = (unsigned char *)b->base + b->current;
r->length = b->used - b->current;
}
void
isc_buffer_active(isc_buffer_t *b, isc_region_t *r) {
/*
* Make 'r' refer to the active region of 'b'.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(r != NULL);
if (b->current < b->active) {
r->base = (unsigned char *)b->base + b->current;
r->length = b->active - b->current;
} else {
r->base = NULL;
r->length = 0;
}
}
void
isc_buffer_setactive(isc_buffer_t *b, unsigned int n) {
unsigned int active;
/*
* Sets the end of the active region 'n' bytes after current.
*/
REQUIRE(VALID_BUFFER(b));
active = b->current + n;
REQUIRE(active <= b->used);
b->active = active;
}
void
isc_buffer_first(isc_buffer_t *b) {
/*
* Make the consumed region empty.
*/
REQUIRE(VALID_BUFFER(b));
b->current = 0;
}
void
isc_buffer_forward(isc_buffer_t *b, unsigned int n) {
/*
* Increase the 'consumed' region of 'b' by 'n' bytes.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(b->current + n <= 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(n <= b->current);
b->current -= n;
}
void
isc_buffer_compact(isc_buffer_t *b) {
unsigned int length;
void *src;
/*
* 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));
src = (unsigned char *)b->base + b->current;
length = b->used - b->current;
(void)memmove(b->base, src, (size_t)length);
if (b->active > b->current)
b->active -= b->current;
else
b->active = 0;
b->current = 0;
b->used = length;
}
isc_uint8_t
isc_buffer_getuint8(isc_buffer_t *b) {
unsigned char *cp;
isc_uint8_t result;
/*
* Read an unsigned 8-bit integer from 'b' and return it.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(b->used - b->current >= 1);
cp = b->base;
cp += b->current;
b->current += 1;
result = ((unsigned int)(cp[0]));
return (result);
}
void
isc_buffer_putuint8(isc_buffer_t *b, isc_uint8_t val)
{
unsigned char *cp;
REQUIRE(VALID_BUFFER(b));
REQUIRE(b->used + 1 <= b->length);
cp = b->base;
cp += b->used;
b->used += 1;
cp[0] = (val & 0x00ff);
}
isc_uint16_t
isc_buffer_getuint16(isc_buffer_t *b) {
unsigned char *cp;
isc_uint16_t result;
/*
* Read an unsigned 16-bit integer in network byte order from 'b',
* convert it to host byte order, and return it.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(b->used - b->current >= 2);
cp = b->base;
cp += b->current;
b->current += 2;
result = ((unsigned int)(cp[0])) << 8;
result |= ((unsigned int)(cp[1]));
return (result);
}
void
isc_buffer_putuint16(isc_buffer_t *b, isc_uint16_t val)
{
unsigned char *cp;
REQUIRE(VALID_BUFFER(b));
REQUIRE(b->used + 2 <= b->length);
cp = b->base;
cp += b->used;
b->used += 2;
cp[0] = (val & 0xff00) >> 8;
cp[1] = (val & 0x00ff);
}
isc_uint32_t
isc_buffer_getuint32(isc_buffer_t *b) {
unsigned char *cp;
isc_uint32_t result;
/*
* Read an unsigned 32-bit integer in network byte order from 'b',
* convert it to host byte order, and return it.
*/
REQUIRE(VALID_BUFFER(b));
REQUIRE(b->used - b->current >= 4);
cp = b->base;
cp += b->current;
b->current += 4;
result = ((unsigned int)(cp[0])) << 24;
result |= ((unsigned int)(cp[1])) << 16;
result |= ((unsigned int)(cp[2])) << 8;
result |= ((unsigned int)(cp[3]));
return (result);
}
void
isc_buffer_putuint32(isc_buffer_t *b, isc_uint32_t val)
{
unsigned char *cp;
REQUIRE(VALID_BUFFER(b));
REQUIRE(b->used + 4 <= b->length);
cp = b->base;
cp += b->used;
b->used += 4;
cp[0] = (val & 0xff000000) >> 24;
cp[1] = (val & 0x00ff0000) >> 16;
cp[2] = (val & 0x0000ff00) >> 8;
cp[3] = (val & 0x000000ff);
}
isc_result_t
isc_buffer_allocate(isc_mem_t *mctx, isc_buffer_t **dynbuffer,
unsigned int length, unsigned int type)
{
isc_buffer_t *dbuf;
REQUIRE(dynbuffer != NULL);
REQUIRE(*dynbuffer == NULL);
dbuf = isc_mem_get(mctx, length + sizeof(isc_buffer_t));
if (dbuf == NULL)
return (ISC_R_NOMEMORY);
isc_buffer_init(dbuf, ((unsigned char *)dbuf) + sizeof(isc_buffer_t),
length, type);
dbuf->mctx = mctx;
*dynbuffer = dbuf;
return (ISC_R_SUCCESS);
}
void
isc_buffer_free(isc_buffer_t **dynbuffer)
{
unsigned int real_length;
isc_buffer_t *dbuf;
isc_mem_t *mctx;
REQUIRE(dynbuffer != NULL);
REQUIRE(VALID_BUFFER(*dynbuffer));
REQUIRE((*dynbuffer)->mctx != NULL);
dbuf = *dynbuffer;
*dynbuffer = NULL; /* destroy external reference */
real_length = dbuf->length + sizeof(isc_buffer_t);
mctx = dbuf->mctx;
dbuf->mctx = NULL;
isc_buffer_invalidate(dbuf);
isc_mem_put(mctx, dbuf, real_length);
}