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73 lines
1.3 KiB
73 lines
1.3 KiB
20 years ago
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/*
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* JFFS2 -- Journalling Flash File System, Version 2.
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*
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* Copyright (C) 2001, 2002 Red Hat, Inc.
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*
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* Created by David Woodhouse <dwmw2@infradead.org>
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*
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* For licensing information, see the file 'LICENCE' in this directory.
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*
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* $Id: pushpull.h,v 1.10 2004/11/16 20:36:11 dwmw2 Exp $
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*
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*/
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#ifndef __PUSHPULL_H__
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#define __PUSHPULL_H__
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#include <linux/errno.h>
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struct pushpull {
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unsigned char *buf;
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unsigned int buflen;
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unsigned int ofs;
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unsigned int reserve;
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};
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static inline void init_pushpull(struct pushpull *pp, char *buf, unsigned buflen, unsigned ofs, unsigned reserve)
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{
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pp->buf = buf;
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pp->buflen = buflen;
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pp->ofs = ofs;
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pp->reserve = reserve;
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}
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static inline int pushbit(struct pushpull *pp, int bit, int use_reserved)
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{
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if (pp->ofs >= pp->buflen - (use_reserved?0:pp->reserve)) {
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return -ENOSPC;
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}
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if (bit) {
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pp->buf[pp->ofs >> 3] |= (1<<(7-(pp->ofs &7)));
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}
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else {
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pp->buf[pp->ofs >> 3] &= ~(1<<(7-(pp->ofs &7)));
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}
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pp->ofs++;
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return 0;
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}
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static inline int pushedbits(struct pushpull *pp)
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{
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return pp->ofs;
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}
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static inline int pullbit(struct pushpull *pp)
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{
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int bit;
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bit = (pp->buf[pp->ofs >> 3] >> (7-(pp->ofs & 7))) & 1;
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pp->ofs++;
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return bit;
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}
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static inline int pulledbits(struct pushpull *pp)
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{
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return pp->ofs;
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}
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#endif /* __PUSHPULL_H__ */
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