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1da177e4 LT |
1 | /* |
2 | * linux/drivers/acorn/scsi/msgqueue.h | |
3 | * | |
4 | * Copyright (C) 1997 Russell King | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * message queue handling | |
11 | */ | |
12 | #ifndef MSGQUEUE_H | |
13 | #define MSGQUEUE_H | |
14 | ||
15 | struct message { | |
16 | char msg[8]; | |
17 | int length; | |
18 | int fifo; | |
19 | }; | |
20 | ||
21 | struct msgqueue_entry { | |
22 | struct message msg; | |
23 | struct msgqueue_entry *next; | |
24 | }; | |
25 | ||
26 | #define NR_MESSAGES 4 | |
27 | ||
28 | typedef struct { | |
29 | struct msgqueue_entry *qe; | |
30 | struct msgqueue_entry *free; | |
31 | struct msgqueue_entry entries[NR_MESSAGES]; | |
32 | } MsgQueue_t; | |
33 | ||
34 | /* | |
35 | * Function: void msgqueue_initialise(MsgQueue_t *msgq) | |
36 | * Purpose : initialise a message queue | |
37 | * Params : msgq - queue to initialise | |
38 | */ | |
39 | extern void msgqueue_initialise(MsgQueue_t *msgq); | |
40 | ||
41 | /* | |
42 | * Function: void msgqueue_free(MsgQueue_t *msgq) | |
43 | * Purpose : free a queue | |
44 | * Params : msgq - queue to free | |
45 | */ | |
46 | extern void msgqueue_free(MsgQueue_t *msgq); | |
47 | ||
48 | /* | |
49 | * Function: int msgqueue_msglength(MsgQueue_t *msgq) | |
50 | * Purpose : calculate the total length of all messages on the message queue | |
51 | * Params : msgq - queue to examine | |
52 | * Returns : number of bytes of messages in queue | |
53 | */ | |
54 | extern int msgqueue_msglength(MsgQueue_t *msgq); | |
55 | ||
56 | /* | |
57 | * Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno) | |
58 | * Purpose : return a message & its length | |
59 | * Params : msgq - queue to obtain message from | |
60 | * : msgno - message number | |
61 | * Returns : pointer to message string, or NULL | |
62 | */ | |
63 | extern struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno); | |
64 | ||
65 | /* | |
66 | * Function: int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...) | |
67 | * Purpose : add a message onto a message queue | |
68 | * Params : msgq - queue to add message on | |
69 | * length - length of message | |
70 | * ... - message bytes | |
71 | * Returns : != 0 if successful | |
72 | */ | |
73 | extern int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...); | |
74 | ||
75 | /* | |
76 | * Function: void msgqueue_flush(MsgQueue_t *msgq) | |
77 | * Purpose : flush all messages from message queue | |
78 | * Params : msgq - queue to flush | |
79 | */ | |
80 | extern void msgqueue_flush(MsgQueue_t *msgq); | |
81 | ||
82 | #endif |