[linux-dvb] Patch 24 / 50: code cleanup for dvbringbuffer

Uwe Bugla uwe.bugla at gmx.de
Fri Jun 23 17:15:51 CEST 2006


#Applies against: 2.6.17
#Signed-off-by: Uwe Bugla <uwe.bugla at gmx.de>
#Changes: fix type and / or tab errors, extracts documentary parts out of the module and transforms them into a documentary text file
--- a/drivers/media/dvb/dvb-core/dvb_ringbuffer.h	2006-05-27 14:03:00
+++ b/drivers/media/dvb/dvb-core/dvb_ringbuffer.h	2006-05-28 17:45:00
@@ -40,67 +40,27 @@
 	wait_queue_head_t queue;
 	spinlock_t        lock;
 };
-
 #define DVB_RINGBUFFER_PKTHDRSIZE 3
-
-
-/*
-** Notes:
-** ------
-** (1) For performance reasons read and write routines don't check buffer sizes
-**     and/or number of bytes free/available. This has to be done before these
-**     routines are called. For example:
-**
-**     *** write <buflen> bytes ***
-**     free = dvb_ringbuffer_free(rbuf);
-**     if (free >= buflen)
-**         count = dvb_ringbuffer_write(rbuf, buffer, buflen);
-**     else
-**         ...
-**
-**     *** read min. 1000, max. <bufsize> bytes ***
-**     avail = dvb_ringbuffer_avail(rbuf);
-**     if (avail >= 1000)
-**         count = dvb_ringbuffer_read(rbuf, buffer, min(avail, bufsize), 0);
-**     else
-**         ...
-**
-** (2) If there is exactly one reader and one writer, there is no need
-**     to lock read or write operations.
-**     Two or more readers must be locked against each other.
-**     Flushing the buffer counts as a read operation.
-**     Two or more writers must be locked against each other.
-*/
 
 /* initialize ring buffer, lock and queue */
 extern void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len);
-
 /* test whether buffer is empty */
 extern int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf);
-
 /* return the number of free bytes in the buffer */
 extern ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf);
-
 /* return the number of bytes waiting in the buffer */
 extern ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf);
-
-
 /* read routines & macros */
-/* ---------------------- */
 /* flush buffer */
 extern void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf);
-
 /* flush buffer protected by spinlock and wake-up waiting task(s) */
 extern void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf);
-
 /* peek at byte <offs> in the buffer */
 #define DVB_RINGBUFFER_PEEK(rbuf,offs)	\
 			(rbuf)->data[((rbuf)->pread+(offs))%(rbuf)->size]
-
 /* advance read ptr by <num> bytes */
 #define DVB_RINGBUFFER_SKIP(rbuf,num)	\
 			(rbuf)->pread=((rbuf)->pread+(num))%(rbuf)->size
-
 /*
 ** read <len> bytes from ring buffer into <buf>
 ** <usermem> specifies whether <buf> resides in user space
--- a/dev/null					2006-05-27 14:03:00
+++ b/Documentation/dvb/dvb_ringbuffer.txt	2006-05-28 17:45:00
@@ -0,0 +1,18 @@
+Notes on this module:
+(1) For performance reasons read and write routines don't check buffer sizes
+	and/or number of bytes free/available. This has to be done before these routines are called.
+For example:
+*** write <buflen> bytes ***
+free = dvb_ringbuffer_free(rbuf);
+if (free >= buflen)
+count = dvb_ringbuffer_write(rbuf, buffer, buflen);
+else
+*** read min. 1000, max. <bufsize> bytes ***
+avail = dvb_ringbuffer_avail(rbuf);
+if (avail >= 1000)
+count = dvb_ringbuffer_read(rbuf, buffer, min(avail, bufsize), 0);
+else
+
+(2) If there is exactly one reader and one writer, there is no need to lock read or write operations.
+	Two or more readers must be locked against each other. Flushing the buffer counts as a read operation.
+	Two or more writers must be locked against each other.

-- 


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