blob: b4c136f8896994723adf2fd934fe80978be9ced6 (
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
|
/**
* @brief simple circular buffer
*/
#ifndef _RING_BUFFER_H_
#define _RING_BUFFER_H_
#ifdef __cplusplus
extern "C"{
#endif
/* The buffer is empty when head == tail.
* The buffer is full when the head is one byte in front of the tail
* The total buffer size must be a power of two
* One byte is left free to distinguish empty from full */
typedef struct ring_buffer {
/** Buffer items are stored into */
volatile uint8 *buf;
/** Index of the next item to remove */
volatile uint16 head;
/** Index where the next item will get inserted */
volatile uint16 tail;
/** Buffer capacity */
uint16 size;
} ring_buffer;
/** Initialise a ring buffer.
@param rb instance to initialise
@param size number of items in the buffer
@param buf buffer to store items into
*/
static inline void rb_init(ring_buffer *rb, uint8 size, uint8 *buf) {
ASSERT(IS_POWER_OF_TWO(size));
rb->head = 0;
rb->tail = 0;
rb->size = size;
rb->buf = buf;
}
/** Append an item onto the end of the ring buffer */
static inline void rb_insert(ring_buffer *rb, uint8 element) {
rb->buf[(rb->tail)++] = element;
rb->tail &= (rb->size - 1);
}
/** Remove and return the first item from the ring buffer */
static inline uint8 rb_remove(ring_buffer *rb) {
uint8 ch = rb->buf[rb->head++];
rb->head &= (rb->size - 1);
return ch;
}
static inline uint32 rb_full_count(ring_buffer *rb) {
/* PENDING: Broken */
return rb->tail - rb->head;
}
/** Discard all items from the buffer */
static inline void rb_reset(ring_buffer *rb) {
rb->tail = rb->head;
}
#ifdef __cplusplus
} // extern "C"
#endif
#endif
|
