aboutsummaryrefslogtreecommitdiffstats
path: root/os/lib/include/chmemheaps.h
blob: f20969a325cbc6ca650ce6648764ceffacd1b060 (plain)
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
171
172
173
174
175
176
177
178
/*
    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio.

    This file is part of ChibiOS.

    ChibiOS 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 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/>.
*/

/**
 * @file    chmemheaps.h
 * @brief   Memory heaps macros and structures.
 *
 * @addtogroup oslib_memheaps
 * @{
 */

#ifndef CHMEMHEAPS_H
#define CHMEMHEAPS_H

#if (CH_CFG_USE_HEAP == TRUE) || defined(__DOXYGEN__)

/*===========================================================================*/
/* Module constants.                                                         */
/*===========================================================================*/

/**
 * @brief   Minimum alignment used for heap.
 * @note    Cannot use the sizeof operator in this macro.
 */
#if (SIZEOF_PTR == 4) || defined(__DOXYGEN__)
#define CH_HEAP_ALIGNMENT   8U
#elif (SIZEOF_PTR == 2)
#define CH_HEAP_ALIGNMENT   4U
#else
#error "unsupported pointer size"
#endif

/*===========================================================================*/
/* Module pre-compile time settings.                                         */
/*===========================================================================*/

/*===========================================================================*/
/* Derived constants and error checks.                                       */
/*===========================================================================*/

#if CH_CFG_USE_MEMCORE == FALSE
#error "CH_CFG_USE_HEAP requires CH_CFG_USE_MEMCORE"
#endif

#if (CH_CFG_USE_MUTEXES == FALSE) && (CH_CFG_USE_SEMAPHORES == FALSE)
#error "CH_CFG_USE_HEAP requires CH_CFG_USE_MUTEXES and/or CH_CFG_USE_SEMAPHORES"
#endif

/*===========================================================================*/
/* Module data structures and types.                                         */
/*===========================================================================*/

/**
 * @brief   Type of a memory heap.
 */
typedef struct memory_heap memory_heap_t;

/**
 * @brief   Type of a memory heap header.
 */
typedef union heap_header heap_header_t;

/**
 * @brief   Memory heap block header.
 */
union heap_header {
  struct {
    heap_header_t       *next;      /**< @brief Next block in free list.    */
    size_t              pages;      /**< @brief Size of the area in pages.  */
  } free;
  struct {
    memory_heap_t       *heap;      /**< @brief Block owner heap.           */
    size_t              size;       /**< @brief Size of the area in bytes.  */
  } used;
};

/**
 * @brief   Structure describing a memory heap.
 */
struct memory_heap {
  memgetfunc2_t         provider;   /**< @brief Memory blocks provider for
                                                this heap.                  */
  heap_header_t         header;     /**< @brief Free blocks list header.    */
#if (CH_CFG_USE_MUTEXES == TRUE) || defined(__DOXYGEN__)
  mutex_t               mtx;        /**< @brief Heap access mutex.          */
#else
  semaphore_t           sem;        /**< @brief Heap access semaphore.      */
#endif
};

/*===========================================================================*/
/* Module macros.                                                            */
/*===========================================================================*/

/**
 * @brief   Allocation of an aligned static heap buffer.
 */
#define CH_HEAP_AREA(name, size)                                            \
  ALIGNED_VAR(CH_HEAP_ALIGNMENT)                                            \
  uint8_t name[MEM_ALIGN_NEXT((size), CH_HEAP_ALIGNMENT)]

/*===========================================================================*/
/* External declarations.                                                    */
/*===========================================================================*/

#ifdef __cplusplus
extern "C" {
#endif
  void _heap_init(void);
  void chHeapObjectInit(memory_heap_t *heapp, void *buf, size_t size);
  void *chHeapAllocAligned(memory_heap_t *heapp, size_t size, unsigned align);
  void chHeapFree(void *p);
  size_t chHeapStatus(memory_heap_t *heapp, size_t *totalp, size_t *largestp);
#ifdef __cplusplus
}
#endif

/*===========================================================================*/
/* Module inline functions.                                                  */
/*===========================================================================*/

/**
 * @brief   Allocates a block of memory from the heap by using the first-fit
 *          algorithm.
 * @details The allocated block is guaranteed to be properly aligned for a
 *          pointer data type.
 *
 * @param[in] heapp     pointer to a heap descriptor or @p NULL in order to
 *                      access the default heap.
 * @param[in] size      the size of the block to be allocated. Note that the
 *                      allocated block may be a bit bigger than the requested
 *                      size for alignment and fragmentation reasons.
 * @return              A pointer to the allocated block.
 * @retval NULL         if the block cannot be allocated.
 *
 * @api
 */
static inline void *chHeapAlloc(memory_heap_t *heapp, size_t size) {

  return chHeapAllocAligned(heapp, size, CH_HEAP_ALIGNMENT);
}

/**
 * @brief   Returns the size of an allocated block.
 * @note    The returned value is the requested size, the real size is the
 *          same value aligned to the next @p CH_HEAP_ALIGNMENT multiple.
 *
 * @param[in] p         pointer to the memory block
 * @return              Size of the block.
 *
 * @api
 */
static inline size_t chHeapGetSize(const void *p) {

  return ((heap_header_t *)p - 1U)->used.size;
}

#endif /* CH_CFG_USE_HEAP == TRUE */

#endif /* CHMEMHEAPS_H */

/** @} */