| /* |
| * 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__ */ |