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/*-
* Copyright (c) 2003, 2004 David Young. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of David Young may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY DAVID YOUNG ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DAVID
* YOUNG BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdlib.h>
#include <string.h>
#include <tcpdump-stdinc.h>
#include "cpack.h"
#include "extract.h"
static u_int8_t *
cpack_next_boundary(u_int8_t *buf, u_int8_t *p, size_t alignment)
{
size_t misalignment = (size_t)(p - buf) % alignment;
if (misalignment == 0)
return p;
return p + (alignment - misalignment);
}
/* Advance to the next wordsize boundary. Return NULL if fewer than
* wordsize bytes remain in the buffer after the boundary. Otherwise,
* return a pointer to the boundary.
*/
static u_int8_t *
cpack_align_and_reserve(struct cpack_state *cs, size_t wordsize)
{
u_int8_t *next;
/* Ensure alignment. */
next = cpack_next_boundary(cs->c_buf, cs->c_next, wordsize);
/* Too little space for wordsize bytes? */
if (next - cs->c_buf + wordsize > cs->c_len)
return NULL;
return next;
}
int
cpack_init(struct cpack_state *cs, u_int8_t *buf, size_t buflen)
{
memset(cs, 0, sizeof(*cs));
cs->c_buf = buf;
cs->c_len = buflen;
cs->c_next = cs->c_buf;
return 0;
}
/* Unpack a 64-bit unsigned integer. */
int
cpack_uint64(struct cpack_state *cs, u_int64_t *u)
{
u_int8_t *next;
if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL)
return -1;
*u = EXTRACT_LE_64BITS(next);
/* Move pointer past the u_int64_t. */
cs->c_next = next + sizeof(*u);
return 0;
}
/* Unpack a 32-bit unsigned integer. */
int
cpack_uint32(struct cpack_state *cs, u_int32_t *u)
{
u_int8_t *next;
if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL)
return -1;
*u = EXTRACT_LE_32BITS(next);
/* Move pointer past the u_int32_t. */
cs->c_next = next + sizeof(*u);
return 0;
}
/* Unpack a 16-bit unsigned integer. */
int
cpack_uint16(struct cpack_state *cs, u_int16_t *u)
{
u_int8_t *next;
if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL)
return -1;
*u = EXTRACT_LE_16BITS(next);
/* Move pointer past the u_int16_t. */
cs->c_next = next + sizeof(*u);
return 0;
}
/* Unpack an 8-bit unsigned integer. */
int
cpack_uint8(struct cpack_state *cs, u_int8_t *u)
{
/* No space left? */
if ((size_t)(cs->c_next - cs->c_buf) >= cs->c_len)
return -1;
*u = *cs->c_next;
/* Move pointer past the u_int8_t. */
cs->c_next++;
return 0;
}
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