include/io/channel-buffer.h

   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 */