Contiki-NG
memb.h
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1 /*
2  * Copyright (c) 2004, Swedish Institute of Computer Science.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  * notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  * notice, this list of conditions and the following disclaimer in the
12  * documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the Institute nor the names of its contributors
14  * may be used to endorse or promote products derived from this software
15  * without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * This file is part of the Contiki operating system.
30  *
31  * Author: Adam Dunkels <adam@sics.se>
32  *
33  */
34 
35 /**
36  * \addtogroup mem
37  * @{
38  */
39 
40 
41 /**
42  * \defgroup memb memb: Memory block management functions
43  *
44  * The memory block allocation routines provide a simple yet powerful
45  * set of functions for managing a set of memory blocks of fixed
46  * size. A set of memory blocks is statically declared with the
47  * MEMB() macro. Memory blocks are allocated from the declared
48  * memory by the memb_alloc() function, and are deallocated with the
49  * memb_free() function.
50  *
51  * @{
52  */
53 
54 
55 /**
56  * \file
57  * Memory block allocation routines.
58  * \author
59  * Adam Dunkels <adam@sics.se>
60  *
61  */
62 
63 #ifndef MEMB_H_
64 #define MEMB_H_
65 
66 #include <stdbool.h>
67 #include "sys/cc.h"
68 
69 /**
70  * Declare a memory block.
71  *
72  * This macro is used to statically declare a block of memory that can
73  * be used by the block allocation functions. The macro statically
74  * declares a C array with a size that matches the specified number of
75  * blocks and their individual sizes.
76  *
77  * Example:
78  \code
79 MEMB(connections, struct connection, 16);
80  \endcode
81  *
82  * \param name The name of the memory block (later used with
83  * memb_init(), memb_alloc() and memb_free()).
84  *
85  * \param structure The name of the struct that the memory block holds
86  *
87  * \param num The total number of memory chunks in the block.
88  *
89  */
90 #define MEMB(name, structure, num) \
91  static bool CC_CONCAT(name,_memb_used)[num]; \
92  static structure CC_CONCAT(name,_memb_mem)[num]; \
93  static struct memb name = {sizeof(structure), num, \
94  CC_CONCAT(name,_memb_used), \
95  (void *)CC_CONCAT(name,_memb_mem)}
96 
97 struct memb {
98  unsigned short size;
99  unsigned short num;
100  bool *used;
101  void *mem;
102 };
103 
104 /**
105  * Initialize a memory block that was declared with MEMB().
106  *
107  * \param m A set of memory blocks previously declared with MEMB().
108  */
109 void memb_init(struct memb *m);
110 
111 /**
112  * Allocate a memory block from a block of memory declared with MEMB().
113  *
114  * \param m A set of memory blocks previously declared with MEMB().
115  */
116 void *memb_alloc(struct memb *m);
117 
118 /**
119  * Deallocate a memory block from a memory block previously declared
120  * with MEMB().
121  *
122  * \param m m A set of memory blocks previously declared with MEMB().
123  *
124  * \param ptr A pointer to the memory block that is to be deallocated.
125  *
126  * \return error code, should be 0 if successfully deallocated or -1 if the
127  * pointer "ptr" did not point to a legal memory block.
128  */
129 int memb_free(struct memb *m, void *ptr);
130 
131 /**
132  * Check if a given address is within a memory area previously
133  * declared with MEMB().
134  *
135  * \param m m A set of memory blocks previously declared with MEMB().
136  *
137  * \param ptr A pointer to the address to check
138  *
139  * \return 1 if the address is part of the memory block; otherwise 0
140  */
141 int memb_inmemb(struct memb *m, void *ptr);
142 
143 /**
144  * Count free memory blocks
145  *
146  * \param m m A set of memory blocks previously declared with MEMB().
147  *
148  * \return the number of free (available) memory blocks
149  */
150 int memb_numfree(struct memb *m);
151 
152 /** @} */
153 /** @} */
154 
155 #endif /* MEMB_H_ */
int memb_free(struct memb *m, void *ptr)
Deallocate a memory block from a memory block previously declared with MEMB().
Definition: memb.c:78
int memb_inmemb(struct memb *m, void *ptr)
Check if a given address is within a memory area previously declared with MEMB(). ...
Definition: memb.c:101
void * memb_alloc(struct memb *m)
Allocate a memory block from a block of memory declared with MEMB().
Definition: memb.c:59
int memb_numfree(struct memb *m)
Count free memory blocks.
Definition: memb.c:108
Default definitions of C compiler quirk work-arounds.
void memb_init(struct memb *m)
Initialize a memory block that was declared with MEMB().
Definition: memb.c:52