xref: /openbmc/qemu/include/io/channel-buffer.h (revision 8fa3b702)
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 #include "qom/object.h"
26 
27 #define TYPE_QIO_CHANNEL_BUFFER "qio-channel-buffer"
28 typedef struct QIOChannelBuffer QIOChannelBuffer;
29 DECLARE_INSTANCE_CHECKER(QIOChannelBuffer, QIO_CHANNEL_BUFFER,
30                          TYPE_QIO_CHANNEL_BUFFER)
31 
32 
33 /**
34  * QIOChannelBuffer:
35  *
36  * The QIOChannelBuffer object provides a channel implementation
37  * that is able to perform I/O to/from a memory buffer.
38  *
39  */
40 
41 struct QIOChannelBuffer {
42     QIOChannel parent;
43     size_t capacity; /* Total allocated memory */
44     size_t usage;    /* Current size of data */
45     size_t offset;   /* Offset for future I/O ops */
46     uint8_t *data;
47 };
48 
49 
50 /**
51  * qio_channel_buffer_new:
52  * @capacity: the initial buffer capacity to allocate
53  *
54  * Allocate a new buffer which is initially empty
55  *
56  * Returns: the new channel object
57  */
58 QIOChannelBuffer *
59 qio_channel_buffer_new(size_t capacity);
60 
61 #endif /* QIO_CHANNEL_BUFFER_H */
62