/*-
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Paul Vixie.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD$
 */

#ifndef _SYS_BITSTRING_H_
#define _SYS_BITSTRING_H_

typedef unsigned char bitstr_t;

/* internal macros */
                                /* byte of the bitstring bit is in */
#define _bit_byte(bit) \
        ((bit) >> 3)

                                /* mask for the bit within its byte */
#define _bit_mask(bit) \
        (1 << ((bit)&0x7))

/* external macros */
                                /* bytes in a bitstring of nbits bits */
#define bitstr_size(nbits) \
        (((nbits) + 7) >> 3)

                                /* allocate a bitstring */
#define bit_alloc(nbits) \
        (bitstr_t *)calloc((size_t)bitstr_size(nbits), sizeof(bitstr_t))

                                /* allocate a bitstring on the stack */
#define bit_decl(name, nbits) \
        ((name)[bitstr_size(nbits)])

                                /* is bit N of bitstring name set? */
#define bit_test(name, bit) \
        ((name)[_bit_byte(bit)] & _bit_mask(bit))

                                /* set bit N of bitstring name */
#define bit_set(name, bit) \
        ((name)[_bit_byte(bit)] |= _bit_mask(bit))

                                /* clear bit N of bitstring name */
#define bit_clear(name, bit) \
        ((name)[_bit_byte(bit)] &= ~_bit_mask(bit))

                                /* clear bits start ... stop in bitstring */
#define bit_nclear(name, start, stop) do { \
        register bitstr_t *_name = (name); \
        register int _start = (start), _stop = (stop); \
        register int _startbyte = _bit_byte(_start); \
        register int _stopbyte = _bit_byte(_stop); \
        if (_startbyte == _stopbyte) { \
                _name[_startbyte] &= ((0xff >> (8 - (_start&0x7))) | \
                                      (0xff << ((_stop&0x7) + 1))); \
        } else { \
                _name[_startbyte] &= 0xff >> (8 - (_start&0x7)); \
                while (++_startbyte < _stopbyte) \
                        _name[_startbyte] = 0; \
                _name[_stopbyte] &= 0xff << ((_stop&0x7) + 1); \
        } \
} while (0)

                                /* set bits start ... stop in bitstring */
#define bit_nset(name, start, stop) do { \
        register bitstr_t *_name = (name); \
        register int _start = (start), _stop = (stop); \
        register int _startbyte = _bit_byte(_start); \
        register int _stopbyte = _bit_byte(_stop); \
        if (_startbyte == _stopbyte) { \
                _name[_startbyte] |= ((0xff << (_start&0x7)) & \
                                    (0xff >> (7 - (_stop&0x7)))); \
        } else { \
                _name[_startbyte] |= 0xff << ((_start)&0x7); \
                while (++_startbyte < _stopbyte) \
                        _name[_startbyte] = 0xff; \
                _name[_stopbyte] |= 0xff >> (7 - (_stop&0x7)); \
        } \
} while (0)

                                /* find first bit clear in name */
#define bit_ffc(name, nbits, value) do { \
        register bitstr_t *_name = (name); \
        register int _byte, _nbits = (nbits); \
        register int _stopbyte = _bit_byte(_nbits - 1), _value = -1; \
        if (_nbits > 0) \
                for (_byte = 0; _byte <= _stopbyte; ++_byte) \
                        if (_name[_byte] != 0xff) { \
                                bitstr_t _lb; \
                                _value = _byte << 3; \
                                for (_lb = _name[_byte]; (_lb&0x1); \
                                    ++_value, _lb >>= 1); \
                                break; \
                        } \
        if (_value >= nbits) \
                _value = -1; \
        *(value) = _value; \
} while (0)

                                /* find first bit set in name */
#define bit_ffs(name, nbits, value) do { \
        register bitstr_t *_name = (name); \
        register int _byte, _nbits = (nbits); \
        register int _stopbyte = _bit_byte(_nbits - 1), _value = -1; \
        if (_nbits > 0) \
                for (_byte = 0; _byte <= _stopbyte; ++_byte) \
                        if (_name[_byte]) { \
                                bitstr_t _lb; \
                                _value = _byte << 3; \
                                for (_lb = _name[_byte]; !(_lb&0x1); \
                                    ++_value, _lb >>= 1); \
                                break; \
                        } \
        if (_value >= nbits) \
                _value = -1; \
        *(value) = _value; \
} while (0)

#endif /* !_SYS_BITSTRING_H_ */