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