30 lines
1.2 KiB
C
30 lines
1.2 KiB
C
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/****************************************************************************
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****************************************************************************
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***
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*** This header was automatically generated from a Linux kernel header
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*** of the same name, to make information necessary for userspace to
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*** call into the kernel available to libc. It contains only constants,
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*** structures, and macros generated from the original header, and thus,
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*** contains no copyrightable information.
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***
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****************************************************************************
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****************************************************************************/
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#ifndef _LINUX_CIRC_BUF_H
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#define _LINUX_CIRC_BUF_H 1
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struct circ_buf {
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char *buf;
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int head;
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int tail;
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};
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#define CIRC_CNT(head,tail,size) (((head) - (tail)) & ((size)-1))
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#define CIRC_SPACE(head,tail,size) CIRC_CNT((tail),((head)+1),(size))
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#define CIRC_CNT_TO_END(head,tail,size) ({int end = (size) - (tail); int n = ((head) + end) & ((size)-1); n < end ? n : end;})
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#define CIRC_SPACE_TO_END(head,tail,size) ({int end = (size) - 1 - (head); int n = (end + (tail)) & ((size)-1); n <= end ? n : end+1;})
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#endif
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