1 jelson 1.1 /*
 2             * EMLOG: the EMbedded-device LOGger
 3             *

 4 jelson 1.5  * Jeremy Elson <jelson@circlemud.org>
 5             * USC/Information Sciences Institute

 6 jelson 1.1  *

 7 jelson 1.5  * This code is released under the GPL
 8             *
 9             * This is emlog version 0.40, released 13 August 2001
10             * For more information see http://www.circlemud.org/~jelson/software/emlog
11             *

12 jelson 1.6  * $Id: emlog.h,v 1.5 2001/08/13 21:12:48 jelson Exp $

13 jelson 1.1  */
14            
15            #define EMLOG_MAJOR_NUMBER   241
16            #define EMLOG_MAX_SIZE       128 /* max size in kilobytes of a buffer */
17            

18 jelson 1.5 #define EMLOG_VERSION        "0.40"

19 jelson 1.1 
20            /************************ Private Definitions *****************************/
21            
22            struct emlog_info {

23 jelson 1.2 
24            #if defined(DECLARE_WAIT_QUEUE_HEAD)
25              wait_queue_head_t read_q;
26            #else

27 jelson 1.3   struct wait_queue *read_q;

28 jelson 1.2 #endif

29 jelson 1.6 

30 jelson 1.4   unsigned long i_ino;		/* Inode number of this emlog buffer */

31 jelson 1.6   kdev_t i_dev;			/* Device number of this emlog buffer */

32 jelson 1.4   char *data;			/* The circular buffer data */
33              int size;			/* Size of the buffer pointed to by 'data' */
34              int refcount;			/* Files that have this buffer open */
35              int read_point;		/* Offset in circ. buffer of oldest data */
36              int write_point;		/* Offset in circ. buffer of newest data */
37              int offset;			/* Byte number of read_point in the stream */

38 jelson 1.1   struct emlog_info *next;
39            };
40            

41 jelson 1.4 
42            /* amount of data in the queue */
43            #define EMLOG_QLEN(einfo) ( (einfo)->write_point >= (einfo)->read_point ? \

44 jelson 1.1          (einfo)->write_point - (einfo)->read_point : \
45                     (einfo)->size - (einfo)->read_point + (einfo)->write_point)

46 jelson 1.5 
47            /* byte number of the last byte in the queue */
48            #define EMLOG_FIRST_EMPTY_BYTE(einfo) ((einfo)->offset + EMLOG_QLEN(einfo))

49 jelson 1.1 			

50 jelson 1.5 /* macro to make it more convenient to access the wait q */

51 jelson 1.2 #define EMLOG_READQ(einfo) (&((einfo)->read_q))

52 jelson 1.1