/*
 *        bitvec.h
 *        A rudimentary bit vector class.
 *        AYM 1998-11-22
 */


/*
This file is part of Yadex.

Yadex incorporates code from DEU 5.21 that was put in the public domain in
1994 by Raphaël Quinet and Brendon Wyber.

The rest of Yadex is Copyright © 1997-2003 André Majorel and others.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place, Suite 330, Boston, MA 02111-1307, USA.
*/


#ifndef YH_BITVEC                /* DO NOT INSERT ANYTHING BEFORE THIS LINE */
#define YH_BITVEC


#include <limits.h>

#include "yerror.h"
#include "ymemory.h"


typedef enum
{
    BV_SET = 's',
    BV_CLEAR = 'c',
    BV_TOGGLE = 't'
} bitvec_op_t;


extern const char _bitvec_msg1[];


class bitvec_c
{
    public: bitvec_c(size_t n_elements)
    {
        a = (char *) GetMemory(n_elements / CHAR_BIT + 1);
        memset(a, 0, n_elements / CHAR_BIT + 1);
        _n_elements = n_elements;
    }

     ~bitvec_c()
    {
        FreeMemory(a);
    }

    size_t nelements() const        // Return the number of elements
    {
        return _n_elements;
    }

    int get(size_t n) const        // Get bit <n>
    {
        return a[n / CHAR_BIT] & (1 << (n % CHAR_BIT));
    }

    void set(size_t n)                // Set bit <n> to 1
    {
        a[n / CHAR_BIT] |= 1 << (n % CHAR_BIT);
    }

    void unset(size_t n)        // Set bit <n> to 0
    {
        a[n / CHAR_BIT] &= ~(1 << (n % CHAR_BIT));
    }

    void toggle(size_t n)        // Toggle bit <n>
    {
        a[n / CHAR_BIT] ^= (1 << (n % CHAR_BIT));
    }

    void frob(size_t n, bitvec_op_t op)        // Set, unset or toggle bit <n>
    {
        if (op == BV_SET)
            set(n);
        else if (op == BV_CLEAR)
            unset(n);
        else if (op == BV_TOGGLE)
            toggle(n);
        else
            nf_bug(_bitvec_msg1, (int) op);
    }

  private:
    size_t _n_elements;
    char *a;
};


#endif /* DO NOT ADD ANYTHING AFTER THIS LINE */