view data/model/PowerOfSqrtTwoZoomConstraint.cpp @ 1833:21c792334c2e sensible-delimited-data-strings

Rewrite all the DelimitedDataString stuff so as to return vectors of individual cell strings rather than having the classes add the delimiters themselves. Rename accordingly to names based on StringExport. Take advantage of this in the CSV writer code so as to properly quote cells that contain delimiter characters.

/* -*- 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.
*/

#include "PowerOfSqrtTwoZoomConstraint.h"

#include <iostream>
#include <cmath>

#include "base/Debug.h"


ZoomLevel
PowerOfSqrtTwoZoomConstraint::getNearestZoomLevel(ZoomLevel requested,
                                                  RoundingDirection dir) const
{
    int type, power;
    int blockSize;

    if (requested.zone == ZoomLevel::FramesPerPixel) {
        blockSize = getNearestBlockSize(requested.level, type, power, dir);
        return { requested.zone, blockSize };
    } else {
        RoundingDirection opposite = dir;
        if (dir == RoundUp) opposite = RoundDown;
        else if (dir == RoundDown) opposite = RoundUp;
        blockSize = getNearestBlockSize(requested.level, type, power, opposite);
        if (blockSize > getMinZoomLevel().level) {
            blockSize = getMinZoomLevel().level;
        }
        if (blockSize == 1) {
            return { ZoomLevel::FramesPerPixel, 1 };
        } else {
            return { requested.zone, blockSize };
        }
    }
}

int
PowerOfSqrtTwoZoomConstraint::getNearestBlockSize(int blockSize,
                                                  int &type, 
                                                  int &power,
                                                  RoundingDirection dir) const
{
//    SVCERR << "given " << blockSize << endl;

    int minCachePower = getMinCachePower();

    if (blockSize < (1 << minCachePower)) {
        type = -1;
        power = 0;
        float val = 1.0, prevVal = 1.0;
        while (val + 0.01 < blockSize) {
            prevVal = val;
            val *= sqrtf(2.f);
        }
        int rval = int(val + 0.01f);
//        SVCERR << "got val = " << val << ", rval = " << rval << ", prevVal = " << prevVal << endl;
        if (rval != blockSize && dir != RoundUp) {
            if (dir == RoundDown) {
                rval = int(prevVal + 0.01f);
            } else if (val - float(blockSize) < float(blockSize) - prevVal) {
                rval = int(val + 0.01f);
            } else {
                rval = int(prevVal + 0.01);
            }
        }
//        SVCERR << "returning " << rval << endl;
        return rval;
    }

    int prevBase = (1 << minCachePower);
    int prevPower = minCachePower;
    int prevType = 0;

    int result = 0;

    for (unsigned int i = 0; ; ++i) {

        power = minCachePower + i/2;
        type = i % 2;

        int base;
        if (type == 0) {
            base = (1 << power);
        } else {
            base = (((unsigned int)((1 << minCachePower) * sqrt(2.) + 0.01))
                    << (power - minCachePower));
        }

//        SVCERR << "Testing base " << base << " (i = " << i << ", power = " << power << ", type = " << type << ")" << endl;

        if (base == blockSize) {
            result = base;
//            SVCERR << "Equal, accepting" << endl;
            break;
        }

        if (base > blockSize) {
            if (dir == RoundNearest) {
                if (base - blockSize < blockSize - prevBase) {
                    dir = RoundUp;
//                    SVCERR << "Closer to " << base << " than " << prevBase
//                           << ", rounding up" << endl;
                } else {
                    dir = RoundDown;
//                    SVCERR << "Closer to " << prevBase << " than " << base
//                           << ", rounding down" << endl;
                }
            }
            if (dir == RoundUp) {
                result = base;
                break;
            } else {
                type = prevType;
                power = prevPower;
                result = prevBase;
                break;
            }
        }

        prevType = type;
        prevPower = power;
        prevBase = base;
    }

    if (result > getMaxZoomLevel().level) {
        result = getMaxZoomLevel().level;
    }

//    SVCERR << "Returning result " << result << endl;

    return result;
}