annotate base/ResizeableBitset.h @ 537:3cc4b7cd2aa5

* Merge from one-fftdataserver-per-fftmodel branch.  This bit of
reworking (which is not described very accurately by the title of
the branch) turns the MatrixFile object into something that either
reads or writes, but not both, and separates the FFT file cache
reader and writer implementations separately.  This allows the
FFT data server to have a single thread owning writers and one reader
per "customer" thread, and for all locking to be vastly simplified
and concentrated in the data server alone (because none of the
classes it makes use of is used in more than one thread at a time).
The result is faster and more trustworthy code.

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 Chris Cannam.
    
    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.  See the file
    COPYING included with this distribution for more information.
*/

#ifndef _RESIZEABLE_BITMAP_H_
#define _RESIZEABLE_BITMAP_H_

#include <vector>
#include <stdint.h>

class ResizeableBitset {

public:
    ResizeableBitset() : m_bits(0) {
    }
    ResizeableBitset(size_t size) : m_bits(new std::vector<uint8_t>) {
        m_bits->assign((size >> 3) + 1, 0);
    }
    ResizeableBitset(const ResizeableBitset &b) {
        m_bits = new std::vector<uint8_t>(*b.m_bits);
    }
    ResizeableBitset &operator=(const ResizeableBitset &b) {
        if (&b != this) return *this;
        delete m_bits;
        m_bits = new std::vector<uint8_t>(*b.m_bits);
        return *this;
    }
    ~ResizeableBitset() {
        delete m_bits;
    }
    
    void resize(size_t bits) { // losing all data
        if (!m_bits || bits < m_bits->size()) {
            delete m_bits;
            m_bits = new std::vector<uint8_t>;
        }
        m_bits->assign((bits >> 3) + 1, 0);
    }
    
    bool get(size_t column) const {
        return ((*m_bits)[column >> 3]) & (1u << (column & 0x07));
    }
    
    void set(size_t column) {
        ((*m_bits)[column >> 3]) |=  (uint8_t(1) << (column & 0x07));
    }

    void reset(size_t column) {
        ((*m_bits)[column >> 3]) &= ~(uint8_t(1) << (column & 0x07));
    }

    void copy(size_t source, size_t dest) {
        get(source) ? set(dest) : reset(dest);
    }
    
private:
    std::vector<uint8_t> *m_bits;
};


#endif