chmboxes.h
6.25 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011,2012 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
---
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes ChibiOS/RT, without being obliged to provide
the source code for any proprietary components. See the file exception.txt
for full details of how and when the exception can be applied.
*/
/**
* @file chmboxes.h
* @brief Mailboxes macros and structures.
*
* @addtogroup mailboxes
* @{
*/
#ifndef _CHMBOXES_H_
#define _CHMBOXES_H_
#if CH_USE_MAILBOXES || defined(__DOXYGEN__)
/*
* Module dependencies check.
*/
#if !CH_USE_SEMAPHORES
#error "CH_USE_MAILBOXES requires CH_USE_SEMAPHORES"
#endif
/**
* @brief Structure representing a mailbox object.
*/
typedef struct {
msg_t *mb_buffer; /**< @brief Pointer to the mailbox
buffer. */
msg_t *mb_top; /**< @brief Pointer to the location
after the buffer. */
msg_t *mb_wrptr; /**< @brief Write pointer. */
msg_t *mb_rdptr; /**< @brief Read pointer. */
Semaphore mb_fullsem; /**< @brief Full counter
@p Semaphore. */
Semaphore mb_emptysem; /**< @brief Empty counter
@p Semaphore. */
} Mailbox;
#ifdef __cplusplus
extern "C" {
#endif
void chMBInit(Mailbox *mbp, msg_t *buf, cnt_t n);
void chMBReset(Mailbox *mbp);
msg_t chMBPost(Mailbox *mbp, msg_t msg, systime_t timeout);
msg_t chMBPostS(Mailbox *mbp, msg_t msg, systime_t timeout);
msg_t chMBPostI(Mailbox *mbp, msg_t msg);
msg_t chMBPostAhead(Mailbox *mbp, msg_t msg, systime_t timeout);
msg_t chMBPostAheadS(Mailbox *mbp, msg_t msg, systime_t timeout);
msg_t chMBPostAheadI(Mailbox *mbp, msg_t msg);
msg_t chMBFetch(Mailbox *mbp, msg_t *msgp, systime_t timeout);
msg_t chMBFetchS(Mailbox *mbp, msg_t *msgp, systime_t timeout);
msg_t chMBFetchI(Mailbox *mbp, msg_t *msgp);
#ifdef __cplusplus
}
#endif
/**
* @name Macro Functions
* @{
*/
/**
* @brief Returns the mailbox buffer size.
*
* @param[in] mbp the pointer to an initialized Mailbox object
*
* @iclass
*/
#define chMBSizeI(mbp) \
((mbp)->mb_top - (mbp)->mb_buffer)
/**
* @brief Returns the number of free message slots into a mailbox.
* @note Can be invoked in any system state but if invoked out of a locked
* state then the returned value may change after reading.
* @note The returned value can be less than zero when there are waiting
* threads on the internal semaphore.
*
* @param[in] mbp the pointer to an initialized Mailbox object
* @return The number of empty message slots.
*
* @iclass
*/
#define chMBGetFreeCountI(mbp) chSemGetCounterI(&(mbp)->mb_emptysem)
/**
* @brief Returns the number of used message slots into a mailbox.
* @note Can be invoked in any system state but if invoked out of a locked
* state then the returned value may change after reading.
* @note The returned value can be less than zero when there are waiting
* threads on the internal semaphore.
*
* @param[in] mbp the pointer to an initialized Mailbox object
* @return The number of queued messages.
*
* @iclass
*/
#define chMBGetUsedCountI(mbp) chSemGetCounterI(&(mbp)->mb_fullsem)
/**
* @brief Returns the next message in the queue without removing it.
* @pre A message must be waiting in the queue for this function to work
* or it would return garbage. The correct way to use this macro is
* to use @p chMBGetFullCountI() and then use this macro, all within
* a lock state.
*
* @iclass
*/
#define chMBPeekI(mbp) (*(mbp)->mb_rdptr)
/** @} */
/**
* @brief Data part of a static mailbox initializer.
* @details This macro should be used when statically initializing a
* mailbox that is part of a bigger structure.
*
* @param[in] name the name of the mailbox variable
* @param[in] buffer pointer to the mailbox buffer area
* @param[in] size size of the mailbox buffer area
*/
#define _MAILBOX_DATA(name, buffer, size) { \
(msg_t *)(buffer), \
(msg_t *)(buffer) + size, \
(msg_t *)(buffer), \
(msg_t *)(buffer), \
_SEMAPHORE_DATA(name.mb_fullsem, 0), \
_SEMAPHORE_DATA(name.mb_emptysem, size), \
}
/**
* @brief Static mailbox initializer.
* @details Statically initialized mailboxes require no explicit
* initialization using @p chMBInit().
*
* @param[in] name the name of the mailbox variable
* @param[in] buffer pointer to the mailbox buffer area
* @param[in] size size of the mailbox buffer area
*/
#define MAILBOX_DECL(name, buffer, size) \
Mailbox name = _MAILBOX_DATA(name, buffer, size)
#endif /* CH_USE_MAILBOXES */
#endif /* _CHMBOXES_H_ */
/** @} */