xref: /openbmc/qemu/include/io/channel-buffer.h (revision 9af9e0fe)
1 /*
2  * QEMU I/O channels memory buffer driver
3  *
4  * Copyright (c) 2015 Red Hat, Inc.
5  *
6  * This library is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2 of the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18  *
19  */
20 
21 #ifndef QIO_CHANNEL_BUFFER_H__
22 #define QIO_CHANNEL_BUFFER_H__
23 
24 #include "io/channel.h"
25 
26 #define TYPE_QIO_CHANNEL_BUFFER "qio-channel-buffer"
27 #define QIO_CHANNEL_BUFFER(obj)                                     \
28     OBJECT_CHECK(QIOChannelBuffer, (obj), TYPE_QIO_CHANNEL_BUFFER)
29 
30 typedef struct QIOChannelBuffer QIOChannelBuffer;
31 
32 /**
33  * QIOChannelBuffer:
34  *
35  * The QIOChannelBuffer object provides a channel implementation
36  * that is able to perform I/O to/from a memory buffer.
37  *
38  */
39 
40 struct QIOChannelBuffer {
41     QIOChannel parent;
42     size_t capacity; /* Total allocated memory */
43     size_t usage;    /* Current size of data */
44     size_t offset;   /* Offset for future I/O ops */
45     char *data;
46 };
47 
48 
49 /**
50  * qio_channel_buffer_new:
51  * @capacity: the initial buffer capacity to allocate
52  *
53  * Allocate a new buffer which is initially empty
54  *
55  * Returns: the new channel object
56  */
57 QIOChannelBuffer *
58 qio_channel_buffer_new(size_t capacity);
59 
60 #endif /* QIO_CHANNEL_BUFFER_H__ */
61