blob: 2ebacda5de40434c7c0b41dd0fd228ebbf6ca152 (
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
|
#ifndef _LINUX_CIRC_BUF_H
#define _LINUX_CIRC_BUF_H 1
struct circ_buf {
char *buf;
int head;
int tail;
};
#define CIRC_CNT(head,tail,size) (((head) - (tail)) & ((size)-1))
#define CIRC_SPACE(head,tail,size) CIRC_CNT((tail),((head)+1),(size))
#define CIRC_CNT_TO_END(head,tail,size) \
({int end = (size) - (tail); \
int n = ((head) + end) & ((size)-1); \
n < end ? n : end;})
#define CIRC_SPACE_TO_END(head,tail,size) \
({int end = (size) - 1 - (head); \
int n = (end + (tail)) & ((size)-1); \
n <= end ? n : end+1;})
#endif
|
