view data/model/PowerOfSqrtTwoZoomConstraint.cpp @ 1310:aa1b1fc2d018 mp3-gapless

Stop reporting sync errors only when we really are at eof, i.e. after the input callback has been called again (previously we just tested whether we'd buffered up all the input, which of course we do in one go at the start)

/* -*- 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>


int
PowerOfSqrtTwoZoomConstraint::getNearestBlockSize(int blockSize,
						  RoundingDirection dir) const
{
    int type, power;
    int rv = getNearestBlockSize(blockSize, type, power, dir);
    return rv;
}

int
PowerOfSqrtTwoZoomConstraint::getNearestBlockSize(int blockSize,
						  int &type, 
						  int &power,
						  RoundingDirection dir) const
{
//    cerr << "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;
	if (dir == RoundUp) rval = int(val + 0.01f);
	else 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);
//	SVDEBUG << "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));
	}

//	SVDEBUG << "Testing base " << base << endl;

        if (base == blockSize) {
            result = base;
            break;
        }

	if (base > blockSize) {
	    if (dir == RoundNearest) {
		if (base - blockSize < blockSize - prevBase) {
		    dir = RoundUp;
		} else {
		    dir = RoundDown;
		}
	    }
	    if (dir == RoundUp) {
		result = base;
		break;
	    } else {
		type = prevType;
		power = prevPower;
		result = prevBase;
		break;
	    }
	}

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

    if (result > getMaxZoomLevel()) result = getMaxZoomLevel();
    return result;
}