/* * 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__ */