contrib/pgcrypto/mbuf.h

   1 /*
   2  * mbuf.h
   3  *              Memory buffer operations.
   4  *
   5  * Copyright (c) 2005 Marko Kreen
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *        notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *        notice, this list of conditions and the following disclaimer in the
  15  *        documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.      IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * $PostgreSQL$
  30  */
  31
  32 #ifndef __PX_MBUF_H
  33 #define __PX_MBUF_H
  34
  35 typedef struct MBuf MBuf;
  36 typedef struct PushFilter PushFilter;
  37 typedef struct PullFilter PullFilter;
  38 typedef struct PushFilterOps PushFilterOps;
  39 typedef struct PullFilterOps PullFilterOps;
  40
  41 struct PushFilterOps
  42 {
  43         /*
  44          * should return needed buffer size, 0- no buffering, <0 on error if NULL,
  45          * no buffering, and priv=init_arg
  46          */
  47         int                     (*init) (PushFilter *next, void *init_arg, void **priv_p);
  48
  49         /*
  50          * send data to next.  should consume all? if null, it will be simply
  51          * copied (in-place) returns 0 on error
  52          */
  53         int                     (*push) (PushFilter *next, void *priv,
  54                                                                          const uint8 *src, int len);
  55         int                     (*flush) (PushFilter *next, void *priv);
  56         void            (*free) (void *priv);
  57 };
  58
  59 struct PullFilterOps
  60 {
  61         /*
  62          * should return needed buffer size, 0- no buffering, <0 on error if NULL,
  63          * no buffering, and priv=init_arg
  64          */
  65         int                     (*init) (void **priv_p, void *init_arg, PullFilter *src);
  66
  67         /*
  68          * request data from src, put result ptr to data_p can use ptr from src or
  69          * use buf as work area if NULL in-place copy
  70          */
  71         int                     (*pull) (void *priv, PullFilter *src, int len,
  72                                                                          uint8 **data_p, uint8 *buf, int buflen);
  73         void            (*free) (void *priv);
  74 };
  75
  76 /*
  77  * Memory buffer
  78  */
  79 MBuf       *mbuf_create(int len);
  80 MBuf       *mbuf_create_from_data(const uint8 *data, int len);
  81 int                     mbuf_tell(MBuf *mbuf);
  82 int                     mbuf_avail(MBuf *mbuf);
  83 int                     mbuf_size(MBuf *mbuf);
  84 int                     mbuf_grab(MBuf *mbuf, int len, uint8 **data_p);
  85 int                     mbuf_steal_data(MBuf *mbuf, uint8 **data_p);
  86 int                     mbuf_append(MBuf *dst, const uint8 *buf, int cnt);
  87 int                     mbuf_rewind(MBuf *mbuf);
  88 int                     mbuf_free(MBuf *mbuf);
  89
  90 /*
  91  * Push filter
  92  */
  93 int pushf_create(PushFilter **res, const PushFilterOps *ops, void *init_arg,
  94                          PushFilter *next);
  95 int                     pushf_write(PushFilter *mp, const uint8 *data, int len);
  96 void            pushf_free_all(PushFilter *mp);
  97 void            pushf_free(PushFilter *mp);
  98 int                     pushf_flush(PushFilter *mp);
  99
 100 int                     pushf_create_mbuf_writer(PushFilter **mp_p, MBuf *mbuf);
 101
 102 /*
 103  * Pull filter
 104  */
 105 int pullf_create(PullFilter **res, const PullFilterOps *ops,
 106                          void *init_arg, PullFilter *src);
 107 int                     pullf_read(PullFilter *mp, int len, uint8 **data_p);
 108 int pullf_read_max(PullFilter *mp, int len,
 109                            uint8 **data_p, uint8 *tmpbuf);
 110 void            pullf_free(PullFilter *mp);
 111 int                     pullf_read_fixed(PullFilter *src, int len, uint8 *dst);
 112
 113 int                     pullf_create_mbuf_reader(PullFilter **pf_p, MBuf *mbuf);
 114
 115 #define GETBYTE(pf, dst) \
 116         do { \
 117                 uint8 __b; \
 118                 int __res = pullf_read_fixed(pf, 1, &__b); \
 119                 if (__res < 0) \
 120                         return __res; \
 121                 (dst) = __b; \
 122         } while (0)
 123
 124 #endif   /* __PX_MBUF_H */