src/rio.h

   1 /*
   2  * Copyright (c) 2009-2012, Pieter Noordhuis <pcnoordhuis at gmail dot com>
   3  * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are met:
   8  *
   9  *   * Redistributions of source code must retain the above copyright notice,
  10  *     this list of conditions and the following disclaimer.
  11  *   * Redistributions in binary form must reproduce the above copyright
  12  *     notice, this list of conditions and the following disclaimer in the
  13  *     documentation and/or other materials provided with the distribution.
  14  *   * Neither the name of Redis nor the names of its contributors may be used
  15  *     to endorse or promote products derived from this software without
  16  *     specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  19  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  22  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  28  * POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31
  32 #ifndef __REDIS_RIO_H
  33 #define __REDIS_RIO_H
  34
  35 #include <stdio.h>
  36 #include <stdint.h>
  37 #include "sds.h"
  38
  39 struct _rio {
  40     /* Backend functions.
  41      * Since this functions do not tolerate short writes or reads the return
  42      * value is simplified to: zero on error, non zero on complete success. */
  43     size_t (*read)(struct _rio *, void *buf, size_t len);
  44     size_t (*write)(struct _rio *, const void *buf, size_t len);
  45     off_t (*tell)(struct _rio *);
  46     /* The update_cksum method if not NULL is used to compute the checksum of all the
  47      * data that was read or written so far. The method should be designed so that
  48      * can be called with the current checksum, and the buf and len fields pointing
  49      * to the new block of data to add to the checksum computation. */
  50     void (*update_cksum)(struct _rio *, const void *buf, size_t len);
  51
  52     /* The current checksum */
  53     uint64_t cksum;
  54
  55     /* Backend-specific vars. */
  56     union {
  57         struct {
  58             sds ptr;
  59             off_t pos;
  60         } buffer;
  61         struct {
  62             FILE *fp;
  63         } file;
  64     } io;
  65 };
  66
  67 typedef struct _rio rio;
  68
  69 /* The following functions are our interface with the stream. They'll call the
  70  * actual implementation of read / write / tell, and will update the checksum
  71  * if needed. */
  72
  73 static inline size_t rioWrite(rio *r, const void *buf, size_t len) {
  74     if (r->update_cksum) r->update_cksum(r,buf,len);
  75     return r->write(r,buf,len);
  76 }
  77
  78 static inline size_t rioRead(rio *r, void *buf, size_t len) {
  79     if (r->read(r,buf,len) == 1) {
  80         if (r->update_cksum) r->update_cksum(r,buf,len);
  81         return 1;
  82     }
  83     return 0;
  84 }
  85
  86 static inline off_t rioTell(rio *r) {
  87     return r->tell(r);
  88 }
  89
  90 void rioInitWithFile(rio *r, FILE *fp);
  91 void rioInitWithBuffer(rio *r, sds s);
  92
  93 size_t rioWriteBulkCount(rio *r, char prefix, int count);
  94 size_t rioWriteBulkString(rio *r, const char *buf, size_t len);
  95 size_t rioWriteBulkLongLong(rio *r, long long l);
  96 size_t rioWriteBulkDouble(rio *r, double d);
  97
  98 void rioGenericUpdateChecksum(rio *r, const void *buf, size_t len);
  99
 100 #endif