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
|
#ifndef RBUFFER_H
#define RBUFFER_H
#include <stddef.h>
struct rbuffer_t {
char* address_begin;
char* address_end;
char* volatile head;
char* volatile tail;
};
#define RBUFFER_ARRAY_INIT(array, length) \
{ \
.address_begin = array, \
.address_end = array + length, \
.head=array, \
.tail=array \
}
static inline int rbuffer_empty(struct rbuffer_t* const rb) {
return rb->head == rb->tail;
}
#define __rbuffer_overlap(rb, ptr) \
if (ptr >= rb->address_end) ptr = rb->address_begin
static inline int rbuffer_write_char(struct rbuffer_t* const rb, char data) {
char* next_head = rb->head + 1;
__rbuffer_overlap(rb, next_head);
if (rb->tail == next_head) return 0;
*rb->head = data;
rb->head = next_head;
return 1;
}
static inline int rbuffer_read_char(struct rbuffer_t* const rb, char* const data) {
if (rbuffer_empty(rb)) return 0;
*data = *rb->tail;
rb->tail += 1;
__rbuffer_overlap(rb, rb->tail);
return 1;
}
static inline size_t rbuffer_write(struct rbuffer_t* const rb, const char* const data, size_t size) {
size_t wrote = 0;
for (size_t i = 0; i < size; ++i) {
if (rbuffer_write_char(rb, data[i])) {
wrote += 1;
} else {
return wrote;
}
}
return wrote;
}
static inline size_t rbuffer_read(struct rbuffer_t* const rb, char* const data, size_t size) {
size_t read = 0;
for (size_t i = 0; i < size; ++i) {
if (rbuffer_read_char(rb, &data[i])) {
read += 1;
} else {
return read;
}
}
return read;
}
#endif
|
