postgresql/contrib/pgcrypto/mbuf.h
2010-09-20 22:08:53 +02:00

125 lines
3.9 KiB
C

/*
* mbuf.h
* Memory buffer operations.
*
* Copyright (c) 2005 Marko Kreen
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 THE AUTHOR OR CONTRIBUTORS 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.
*
* contrib/pgcrypto/mbuf.h
*/
#ifndef __PX_MBUF_H
#define __PX_MBUF_H
typedef struct MBuf MBuf;
typedef struct PushFilter PushFilter;
typedef struct PullFilter PullFilter;
typedef struct PushFilterOps PushFilterOps;
typedef struct PullFilterOps PullFilterOps;
struct PushFilterOps
{
/*
* should return needed buffer size, 0- no buffering, <0 on error if NULL,
* no buffering, and priv=init_arg
*/
int (*init) (PushFilter *next, void *init_arg, void **priv_p);
/*
* send data to next. should consume all? if null, it will be simply
* copied (in-place) returns 0 on error
*/
int (*push) (PushFilter *next, void *priv,
const uint8 *src, int len);
int (*flush) (PushFilter *next, void *priv);
void (*free) (void *priv);
};
struct PullFilterOps
{
/*
* should return needed buffer size, 0- no buffering, <0 on error if NULL,
* no buffering, and priv=init_arg
*/
int (*init) (void **priv_p, void *init_arg, PullFilter *src);
/*
* request data from src, put result ptr to data_p can use ptr from src or
* use buf as work area if NULL in-place copy
*/
int (*pull) (void *priv, PullFilter *src, int len,
uint8 **data_p, uint8 *buf, int buflen);
void (*free) (void *priv);
};
/*
* Memory buffer
*/
MBuf *mbuf_create(int len);
MBuf *mbuf_create_from_data(const uint8 *data, int len);
int mbuf_tell(MBuf *mbuf);
int mbuf_avail(MBuf *mbuf);
int mbuf_size(MBuf *mbuf);
int mbuf_grab(MBuf *mbuf, int len, uint8 **data_p);
int mbuf_steal_data(MBuf *mbuf, uint8 **data_p);
int mbuf_append(MBuf *dst, const uint8 *buf, int cnt);
int mbuf_rewind(MBuf *mbuf);
int mbuf_free(MBuf *mbuf);
/*
* Push filter
*/
int pushf_create(PushFilter **res, const PushFilterOps *ops, void *init_arg,
PushFilter *next);
int pushf_write(PushFilter *mp, const uint8 *data, int len);
void pushf_free_all(PushFilter *mp);
void pushf_free(PushFilter *mp);
int pushf_flush(PushFilter *mp);
int pushf_create_mbuf_writer(PushFilter **mp_p, MBuf *mbuf);
/*
* Pull filter
*/
int pullf_create(PullFilter **res, const PullFilterOps *ops,
void *init_arg, PullFilter *src);
int pullf_read(PullFilter *mp, int len, uint8 **data_p);
int pullf_read_max(PullFilter *mp, int len,
uint8 **data_p, uint8 *tmpbuf);
void pullf_free(PullFilter *mp);
int pullf_read_fixed(PullFilter *src, int len, uint8 *dst);
int pullf_create_mbuf_reader(PullFilter **pf_p, MBuf *mbuf);
#define GETBYTE(pf, dst) \
do { \
uint8 __b; \
int __res = pullf_read_fixed(pf, 1, &__b); \
if (__res < 0) \
return __res; \
(dst) = __b; \
} while (0)
#endif /* __PX_MBUF_H */