mirror of https://github.com/postgres/postgres
125 lines
4.0 KiB
C
125 lines
4.0 KiB
C
/*
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* mbuf.h
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* Memory buffer operations.
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*
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* Copyright (c) 2005 Marko Kreen
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $PostgreSQL: pgsql/contrib/pgcrypto/mbuf.h,v 1.2 2005/10/15 02:49:06 momjian Exp $
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*/
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#ifndef __PX_MBUF_H
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#define __PX_MBUF_H
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typedef struct MBuf MBuf;
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typedef struct PushFilter PushFilter;
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typedef struct PullFilter PullFilter;
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typedef struct PushFilterOps PushFilterOps;
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typedef struct PullFilterOps PullFilterOps;
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struct PushFilterOps
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{
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/*
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* should return needed buffer size, 0- no buffering, <0 on error if NULL,
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* no buffering, and priv=init_arg
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*/
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int (*init) (PushFilter * next, void *init_arg, void **priv_p);
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/*
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* send data to next. should consume all? if null, it will be simply
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* copied (in-place) returns 0 on error
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*/
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int (*push) (PushFilter * next, void *priv,
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const uint8 *src, int len);
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int (*flush) (PushFilter * next, void *priv);
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void (*free) (void *priv);
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};
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struct PullFilterOps
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{
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/*
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* should return needed buffer size, 0- no buffering, <0 on error if NULL,
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* no buffering, and priv=init_arg
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*/
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int (*init) (void **priv_p, void *init_arg, PullFilter * src);
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/*
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* request data from src, put result ptr to data_p can use ptr from src or
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* use buf as work area if NULL in-place copy
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*/
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int (*pull) (void *priv, PullFilter * src, int len,
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uint8 **data_p, uint8 *buf, int buflen);
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void (*free) (void *priv);
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};
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/*
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* Memory buffer
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*/
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MBuf *mbuf_create(int len);
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MBuf *mbuf_create_from_data(const uint8 *data, int len);
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int mbuf_tell(MBuf * mbuf);
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int mbuf_avail(MBuf * mbuf);
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int mbuf_size(MBuf * mbuf);
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int mbuf_grab(MBuf * mbuf, int len, uint8 **data_p);
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int mbuf_steal_data(MBuf * mbuf, uint8 **data_p);
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int mbuf_append(MBuf * dst, const uint8 *buf, int cnt);
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int mbuf_rewind(MBuf * mbuf);
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int mbuf_free(MBuf * mbuf);
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/*
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* Push filter
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*/
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int pushf_create(PushFilter ** res, const PushFilterOps * ops, void *init_arg,
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PushFilter * next);
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int pushf_write(PushFilter * mp, const uint8 *data, int len);
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void pushf_free_all(PushFilter * mp);
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void pushf_free(PushFilter * mp);
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int pushf_flush(PushFilter * mp);
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int pushf_create_mbuf_writer(PushFilter ** mp_p, MBuf * mbuf);
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/*
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* Pull filter
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*/
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int pullf_create(PullFilter ** res, const PullFilterOps * ops,
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void *init_arg, PullFilter * src);
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int pullf_read(PullFilter * mp, int len, uint8 **data_p);
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int pullf_read_max(PullFilter * mp, int len,
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uint8 **data_p, uint8 *tmpbuf);
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void pullf_free(PullFilter * mp);
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int pullf_read_fixed(PullFilter * src, int len, uint8 *dst);
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int pullf_create_mbuf_reader(PullFilter ** pf_p, MBuf * mbuf);
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#define GETBYTE(pf, dst) \
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do { \
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uint8 __b; \
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int __res = pullf_read_fixed(pf, 1, &__b); \
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if (__res < 0) \
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return __res; \
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(dst) = __b; \
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} while (0)
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#endif /* __PX_MBUF_H */
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