include/media/dvb_ringbuffer.h

9  * Copyright (C) 1999-2003 Ralph Metzler & Marcus Metzler
12  * This program is free software; you can redistribute it and/or
15  * of the License, or (at your option) any later version.
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
24 #define _DVB_RINGBUFFER_H_
30  * struct dvb_ringbuffer - Describes a ring buffer used at DVB framework
52 #define DVB_RINGBUFFER_PKTHDRSIZE 3
55  * dvb_ringbuffer_init - initialize ring buffer, lock and queue
59  * @len: bytes from ring buffer into @buf
62 				size_t len);
65  * dvb_ringbuffer_empty - test whether buffer is empty
72  * dvb_ringbuffer_free - returns the number of free bytes in the buffer
81  * dvb_ringbuffer_avail - returns the number of bytes waiting in the buffer
90  * dvb_ringbuffer_reset - resets the ringbuffer to initial state
105  * dvb_ringbuffer_flush - flush buffer
112  * dvb_ringbuffer_flush_spinlock_wakeup- flush buffer protected by spinlock
113  *      and wake-up waiting task(s)
120  * DVB_RINGBUFFER_PEEK - peek at byte @offs in the buffer
125 #define DVB_RINGBUFFER_PEEK(rbuf, offs)	\
126 			((rbuf)->data[((rbuf)->pread + (offs)) % (rbuf)->size])
129  * DVB_RINGBUFFER_SKIP - advance read ptr by @num bytes
134 #define DVB_RINGBUFFER_SKIP(rbuf, num)	{\
135 			(rbuf)->pread = ((rbuf)->pread + (num)) % (rbuf)->size;\
139  * dvb_ringbuffer_read_user - Reads a buffer into a user pointer
143  * @len: bytes from ring buffer into @buf
148  * Return: number of bytes transferred or -EFAULT
151 				   u8 __user *buf, size_t len);
154  * dvb_ringbuffer_read - Reads a buffer into a pointer
158  * @len: bytes from ring buffer into @buf
162  * Return: number of bytes transferred or -EFAULT
165 				   u8 *buf, size_t len);
172  * DVB_RINGBUFFER_WRITE_BYTE - write single byte to ring buffer
177 #define DVB_RINGBUFFER_WRITE_BYTE(rbuf, byte)	\
178 			{ (rbuf)->data[(rbuf)->pwrite] = (byte); \
179 			(rbuf)->pwrite = ((rbuf)->pwrite + 1) % (rbuf)->size; }
182  * dvb_ringbuffer_write - Writes a buffer into the ringbuffer
186  * @len: bytes from ring buffer into @buf
190  * return: number of bytes transferred or -EFAULT
193 				    size_t len);
196  * dvb_ringbuffer_write_user - Writes a buffer received via a user pointer
200  * @len: bytes from ring buffer into @buf
205  * Return: number of bytes transferred or -EFAULT
208 					 const u8 __user *buf, size_t len);
211  * dvb_ringbuffer_pkt_write - Write a packet into the ringbuffer.
215  * @len: Length of buffer (currently limited to 65535 bytes max).
217  * Return: Number of bytes written, or -EFAULT, -ENOMEM, -EINVAL.
220 					size_t len);
223  * dvb_ringbuffer_pkt_read_user - Read from a packet in the ringbuffer.
229  * @len: Size of destination buffer.
231  * Return: Number of bytes read, or -EFAULT.
242 					    size_t len);
245  * dvb_ringbuffer_pkt_read - Read from a packet in the ringbuffer.
253  * @len: Size of destination buffer.
255  * Return: Number of bytes read, or -EFAULT.
258 				       int offset, u8 *buf, size_t len);
261  * dvb_ringbuffer_pkt_dispose - Dispose of a packet in the ring buffer.
269  * dvb_ringbuffer_pkt_next - Get the index of the next packet in a ringbuffer.
272  * @idx: Previous packet index, or -1 to return the first packet index.
275  * returns Packet index (if >=0), or -1 if no packets available.