1 /*
2 * SysDB - src/include/utils/channel.h
3 * Copyright (C) 2013 Sebastian 'tokkee' Harl <sh@tokkee.org>
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
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. 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 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
17 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
28 #ifndef SDB_UTILS_CHANNEL_H
29 #define SDB_UTILS_CHANNEL_H 1
31 #include "core/object.h"
33 #ifdef __cplusplus
34 extern "C" {
35 #endif
37 /*
38 * A channel is an asynchronous I/O multiplexer supporting multiple parallel
39 * readers and writers. A channel may be buffered (depending on its 'size'
40 * attribute). Writing fails unless buffer space is available and reading
41 * fails if no data is available.
42 */
44 struct sdb_channel;
45 typedef struct sdb_channel sdb_channel_t;
47 /*
48 * sdb_channel_create:
49 * Create a new channel for elements of size 'elem_size'. At most, 'size'
50 * elements can be buffered in the channel (default: 1).
51 *
52 * Returns:
53 * - a channel object on success
54 * - a negative value else
55 */
56 sdb_channel_t *
57 sdb_channel_create(size_t size, size_t elem_size);
59 /*
60 * sdb_channel_destroy:
61 * Removing all pending data and destroy the specified channel freeing its
62 * memory.
63 */
64 void
65 sdb_channel_destroy(sdb_channel_t *chan);
67 /*
68 * sdb_channel_write:
69 * Write an element to a channel. The memory pointed to by 'data' is copied to
70 * the buffer based on the channel's element size.
71 *
72 * Returns:
73 * - 0 on success
74 * - a negative value else
75 */
76 int
77 sdb_channel_write(sdb_channel_t *chan, const void *data);
79 /*
80 * sdb_channel_read:
81 * Read an element from a channel. The element is copied to the location
82 * pointed to by 'data' which needs to be large enough to store a whole
83 * element based on the channel's element size.
84 *
85 * Returns:
86 * - 0 on success
87 * - a negative value else
88 */
89 int
90 sdb_channel_read(sdb_channel_t *chan, void *data);
92 #ifdef __cplusplus
93 } /* extern "C" */
94 #endif
96 #endif /* ! SDB_UTILS_CHANNEL_H */
98 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */