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Annotation of 43BSDReno/include/bitstring.h, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1989 The Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * This code is derived from software contributed to Berkeley by
        !             6:  * Paul Vixie.
        !             7:  *
        !             8:  * Redistribution and use in source and binary forms are permitted
        !             9:  * provided that: (1) source distributions retain this entire copyright
        !            10:  * notice and comment, and (2) distributions including binaries display
        !            11:  * the following acknowledgement:  ``This product includes software
        !            12:  * developed by the University of California, Berkeley and its contributors''
        !            13:  * in the documentation or other materials provided with the distribution
        !            14:  * and in all advertising materials mentioning features or use of this
        !            15:  * software. Neither the name of the University nor the names of its
        !            16:  * contributors may be used to endorse or promote products derived
        !            17:  * from this software without specific prior written permission.
        !            18:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
        !            19:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
        !            20:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            21:  *
        !            22:  *     @(#)bitstring.h 5.4 (Berkeley) 6/1/90
        !            23:  */
        !            24: 
        !            25: typedef        unsigned char bitstr_t;
        !            26: 
        !            27: /* internal macros */
        !            28:                                /* byte of the bitstring bit is in */
        !            29: #define        _bit_byte(bit) \
        !            30:        ((bit) >> 3)
        !            31: 
        !            32:                                /* mask for the bit within its byte */
        !            33: #define        _bit_mask(bit) \
        !            34:        (1 << ((bit)&0x7))
        !            35: 
        !            36: /* external macros */
        !            37:                                /* bytes in a bitstring of nbits bits */
        !            38: #define        bitstr_size(nbits) \
        !            39:        ((((nbits) - 1) >> 3) + 1)
        !            40: 
        !            41:                                /* allocate a bitstring */
        !            42: #define        bit_alloc(nbits) \
        !            43:        (bitstr_t *)calloc(1, \
        !            44:            (unsigned int)_bitstr_size(nbits) * sizeof(bitstr_t))
        !            45: 
        !            46:                                /* allocate a bitstring on the stack */
        !            47: #define        bit_decl(name, nbits) \
        !            48:        (name)[bitstr_size(nbits)]
        !            49: 
        !            50:                                /* is bit N of bitstring name set? */
        !            51: #define        bit_test(name, bit) \
        !            52:        ((name)[_bit_byte(bit)] & _bit_mask(bit))
        !            53: 
        !            54:                                /* set bit N of bitstring name */
        !            55: #define        bit_set(name, bit) \
        !            56:        (name)[_bit_byte(bit)] |= _bit_mask(bit)
        !            57: 
        !            58:                                /* clear bit N of bitstring name */
        !            59: #define        bit_clear(name, bit) \
        !            60:        (name)[_bit_byte(bit)] &= ~_bit_mask(bit)
        !            61: 
        !            62:                                /* clear bits start ... stop in bitstring */
        !            63: #define        bit_nclear(name, start, stop) { \
        !            64:        register bitstr_t *_name = name; \
        !            65:        register int _start = start, _stop = stop; \
        !            66:        register int _startbyte = _bit_byte(_start); \
        !            67:        register int _stopbyte = _bit_byte(_stop); \
        !            68:        _name[_startbyte] &= 0xff >> (8 - (_start&0x7)); \
        !            69:        while (++_startbyte < _stopbyte) \
        !            70:                _name[_startbyte] = 0; \
        !            71:        _name[_stopbyte] &= 0xff << ((_stop&0x7) + 1); \
        !            72: }
        !            73: 
        !            74:                                /* set bits start ... stop in bitstring */
        !            75: #define        bit_nset(name, start, stop) { \
        !            76:        register bitstr_t *_name = name; \
        !            77:        register int _start = start, _stop = stop; \
        !            78:        register int _startbyte = _bit_byte(_start); \
        !            79:        register int _stopbyte = _bit_byte(_stop); \
        !            80:        _name[_startbyte] |= 0xff << ((start)&0x7); \
        !            81:        while (++_startbyte < _stopbyte) \
        !            82:            _name[_startbyte] = 0xff; \
        !            83:        _name[_stopbyte] |= 0xff >> (7 - (_stop&0x7)); \
        !            84: }
        !            85: 
        !            86:                                /* find first bit clear in name */
        !            87: #define        bit_ffc(name, nbits, value) { \
        !            88:        register bitstr_t *_name = name; \
        !            89:        register int _byte, _nbits = nbits; \
        !            90:        register int _stopbyte = _bit_byte(_nbits), _value = -1; \
        !            91:        for (_byte = 0; _byte <= _stopbyte; ++_byte) \
        !            92:                if (_name[_byte] != 0xff) { \
        !            93:                        _value = _byte << 3; \
        !            94:                        for (_stopbyte = _name[_byte]; (_stopbyte&0x1); \
        !            95:                            ++_value, _stopbyte >>= 1); \
        !            96:                        break; \
        !            97:                } \
        !            98:        *(value) = _value; \
        !            99: }
        !           100: 
        !           101:                                /* find first bit set in name */
        !           102: #define        bit_ffs(name, nbits, value) { \
        !           103:        register bitstr_t *_name = name; \
        !           104:        register int _byte, _nbits = nbits; \
        !           105:        register int _stopbyte = _bit_byte(_nbits), _value = -1; \
        !           106:        for (_byte = 0; _byte <= _stopbyte; ++_byte) \
        !           107:                if (_name[_byte]) { \
        !           108:                        _value = _byte << 3; \
        !           109:                        for (_stopbyte = _name[_byte]; !(_stopbyte&0x1); \
        !           110:                            ++_value, _stopbyte >>= 1); \
        !           111:                        break; \
        !           112:                } \
        !           113:        *(value) = _value; \
        !           114: }

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