projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * JFFS2 -- Journalling Flash File System, Version 2. | |
| 3 | * | |
| 4 | * Copyright (C) 2001, 2002 Red Hat, Inc. | |
| 5 | * | |
| 6 | * Created by David Woodhouse <[email protected]> | |
| 7 | * | |
| 8 | * For licensing information, see the file 'LICENCE' in this directory. | |
| 9 | * | |
| 10 | * $Id: pushpull.h,v 1.10 2004/11/16 20:36:11 dwmw2 Exp $ | |
| 11 | * | |
| 12 | */ | |
| 13 | ||
| 14 | #ifndef __PUSHPULL_H__ | |
| 15 | #define __PUSHPULL_H__ | |
| 16 | ||
| 17 | #include <linux/errno.h> | |
| 18 | ||
| 19 | struct pushpull { | |
| 20 | unsigned char *buf; | |
| 21 | unsigned int buflen; | |
| 22 | unsigned int ofs; | |
| 23 | unsigned int reserve; | |
| 24 | }; | |
| 25 | ||
| 26 | ||
| 27 | static inline void init_pushpull(struct pushpull *pp, char *buf, unsigned buflen, unsigned ofs, unsigned reserve) | |
| 28 | { | |
| 29 | pp->buf = buf; | |
| 30 | pp->buflen = buflen; | |
| 31 | pp->ofs = ofs; | |
| 32 | pp->reserve = reserve; | |
| 33 | } | |
| 34 | ||
| 35 | static inline int pushbit(struct pushpull *pp, int bit, int use_reserved) | |
| 36 | { | |
| 37 | if (pp->ofs >= pp->buflen - (use_reserved?0:pp->reserve)) { | |
| 38 | return -ENOSPC; | |
| 39 | } | |
| 40 | ||
| 41 | if (bit) { | |
| 42 | pp->buf[pp->ofs >> 3] |= (1<<(7-(pp->ofs &7))); | |
| 43 | } | |
| 44 | else { | |
| 45 | pp->buf[pp->ofs >> 3] &= ~(1<<(7-(pp->ofs &7))); | |
| 46 | } | |
| 47 | pp->ofs++; | |
| 48 | ||
| 49 | return 0; | |
| 50 | } | |
| 51 | ||
| 52 | static inline int pushedbits(struct pushpull *pp) | |
| 53 | { | |
| 54 | return pp->ofs; | |
| 55 | } | |
| 56 | ||
| 57 | static inline int pullbit(struct pushpull *pp) | |
| 58 | { | |
| 59 | int bit; | |
| 60 | ||
| 61 | bit = (pp->buf[pp->ofs >> 3] >> (7-(pp->ofs & 7))) & 1; | |
| 62 | ||
| 63 | pp->ofs++; | |
| 64 | return bit; | |
| 65 | } | |
| 66 | ||
| 67 | static inline int pulledbits(struct pushpull *pp) | |
| 68 | { | |
| 69 | return pp->ofs; | |
| 70 | } | |
| 71 | ||
| 72 | #endif /* __PUSHPULL_H__ */ |