xref: /redis-3.2.3/src/rio.h (revision 40f822da)
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
101