| The Android Open Source Project | a27d2ba | 2008-10-21 07:00:00 -0700 | [diff] [blame] | 1 | /**************************************************************************** |
| 2 | **************************************************************************** |
| 3 | *** |
| 4 | *** This header was automatically generated from a Linux kernel header |
| 5 | *** of the same name, to make information necessary for userspace to |
| 6 | *** call into the kernel available to libc. It contains only constants, |
| 7 | *** structures, and macros generated from the original header, and thus, |
| 8 | *** contains no copyrightable information. |
| 9 | *** |
| 10 | **************************************************************************** |
| 11 | ****************************************************************************/ |
| 12 | #ifndef _LINUX_CIRC_BUF_H |
| 13 | #define _LINUX_CIRC_BUF_H 1 |
| 14 | |
| 15 | struct circ_buf { |
| 16 | char *buf; |
| 17 | int head; |
| 18 | int tail; |
| 19 | }; |
| 20 | |
| 21 | #define CIRC_CNT(head,tail,size) (((head) - (tail)) & ((size)-1)) |
| 22 | |
| 23 | #define CIRC_SPACE(head,tail,size) CIRC_CNT((tail),((head)+1),(size)) |
| 24 | |
| 25 | #define CIRC_CNT_TO_END(head,tail,size) ({int end = (size) - (tail); int n = ((head) + end) & ((size)-1); n < end ? n : end;}) |
| 26 | |
| 27 | #define CIRC_SPACE_TO_END(head,tail,size) ({int end = (size) - 1 - (head); int n = (end + (tail)) & ((size)-1); n <= end ? n : end+1;}) |
| 28 | |
| 29 | #endif |