bitvector.h

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/*
This program is distributed under the terms of the 'MIT license'. The text
of this licence follows...

Copyright (c) 2007 J.D.Medhurst (a.k.a. Tixy)

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

#ifndef BITVECTOR_H
#define BITVECTOR_H

const unsigned BitVectorIndexShift =
    sizeof(unsigned)==2 ? 4 :   // assume 2 bytes is 2^4 bits
    sizeof(unsigned)==4 ? 5 :   // assume 4 bytes is 2^5 bits
    sizeof(unsigned)==8 ? 6 :   // assume 8 bytes is 2^6 bits
    ~0u;                        // value which will cause later compile error

const unsigned BitVectorIndexMask = (1<<BitVectorIndexShift)-1;

// check that size of 'unsigned' is really as we specified...
ASSERT_COMPILE( (1u<<BitVectorIndexMask) == (~0u>>1)+1 );


template <size_t S>
struct BitVectorBits
    {
    unsigned Buffer[(S+BitVectorIndexMask)>>BitVectorIndexShift];

    inline operator unsigned*()
        {
        return Buffer;
        }
    };


template <>
struct BitVectorBits<0>
    {
    inline operator unsigned*()
        {
        return 0;
        }
    };


class BitVectorPointer
    {
public:
    template <size_t S>
    inline BitVectorPointer(BitVectorBits<S>& bits)
        : Bits(bits), Size(S)
        {}

    inline BitVectorPointer(unsigned* bits, size_t size)
        : Bits(bits), Size(size)
        {}

    inline BitVectorPointer()
        {}

    void Reset();

    int Test(unsigned index);

    void Set(unsigned index);

    void Clear(unsigned index);

    int TestSet(unsigned index, size_t count);

    int TestClear(unsigned index, size_t count);

    void Set(unsigned index, size_t count);

    void Clear(unsigned index, size_t count);

    int Find(size_t count, unsigned state);

public:
    unsigned*   Bits; 
    size_t      Size; 
    };


template <size_t S>
class BitVector : public BitVectorPointer, public BitVectorBits<S>
    {
public:
    inline BitVector()
        : BitVectorPointer(static_cast<BitVectorBits<S>&>(*this))
        {
        Reset();
        }
    };

 // End of group

#endif // BITVECTOR_H