lbajardsilogic@0: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
lbajardsilogic@0: 
lbajardsilogic@0: /*
lbajardsilogic@0:     Sonic Visualiser
lbajardsilogic@0:     An audio file viewer and annotation editor.
lbajardsilogic@0:     Centre for Digital Music, Queen Mary, University of London.
lbajardsilogic@0:     This file copyright 2006 Chris Cannam.
lbajardsilogic@0:     
lbajardsilogic@0:     This program is free software; you can redistribute it and/or
lbajardsilogic@0:     modify it under the terms of the GNU General Public License as
lbajardsilogic@0:     published by the Free Software Foundation; either version 2 of the
lbajardsilogic@0:     License, or (at your option) any later version.  See the file
lbajardsilogic@0:     COPYING included with this distribution for more information.
lbajardsilogic@0: */
lbajardsilogic@0: 
lbajardsilogic@0: #include "PowerOfSqrtTwoZoomConstraint.h"
lbajardsilogic@0: 
lbajardsilogic@0: #include <iostream>
lbajardsilogic@0: #include <cmath>
lbajardsilogic@0: 
lbajardsilogic@0: 
lbajardsilogic@0: size_t
lbajardsilogic@0: PowerOfSqrtTwoZoomConstraint::getNearestBlockSize(size_t blockSize,
lbajardsilogic@0: 						  RoundingDirection dir) const
lbajardsilogic@0: {
lbajardsilogic@0:     int type, power;
lbajardsilogic@0:     size_t rv = getNearestBlockSize(blockSize, type, power, dir);
lbajardsilogic@0:     return rv;
lbajardsilogic@0: }
lbajardsilogic@0: 
lbajardsilogic@0: size_t
lbajardsilogic@0: PowerOfSqrtTwoZoomConstraint::getNearestBlockSize(size_t blockSize,
lbajardsilogic@0: 						  int &type, 
lbajardsilogic@0: 						  int &power,
lbajardsilogic@0: 						  RoundingDirection dir) const
lbajardsilogic@0: {
lbajardsilogic@0: //    std::cerr << "given " << blockSize << std::endl;
lbajardsilogic@0: 
lbajardsilogic@0:     size_t minCachePower = getMinCachePower();
lbajardsilogic@0: 
lbajardsilogic@0:     if (blockSize < (1U << minCachePower)) {
lbajardsilogic@0: 	type = -1;
lbajardsilogic@0: 	power = 0;
lbajardsilogic@0: 	float val = 1.0, prevVal = 1.0;
lbajardsilogic@0: 	while (val + 0.01 < blockSize) {
lbajardsilogic@0: 	    prevVal = val;
lbajardsilogic@0: 	    val *= sqrt(2.0);
lbajardsilogic@0: 	}
lbajardsilogic@0: 	size_t rval;
lbajardsilogic@0: 	if (dir == RoundUp) rval = size_t(val + 0.01);
lbajardsilogic@0: 	else if (dir == RoundDown) rval = size_t(prevVal + 0.01);
lbajardsilogic@0: 	else if (val - blockSize < blockSize - prevVal) rval = size_t(val + 0.01);
lbajardsilogic@0: 	else rval = size_t(prevVal + 0.01);
lbajardsilogic@0: //	std::cerr << "returning " << rval << std::endl;
lbajardsilogic@0: 	return rval;
lbajardsilogic@0:     }
lbajardsilogic@0: 
lbajardsilogic@0:     unsigned int prevBase = (1 << minCachePower);
lbajardsilogic@0:     unsigned int prevPower = minCachePower;
lbajardsilogic@0:     unsigned int prevType = 0;
lbajardsilogic@0: 
lbajardsilogic@0:     size_t result = 0;
lbajardsilogic@0: 
lbajardsilogic@0:     for (unsigned int i = 0; ; ++i) {
lbajardsilogic@0: 
lbajardsilogic@0: 	power = minCachePower + i/2;
lbajardsilogic@0: 	type = i % 2;
lbajardsilogic@0: 
lbajardsilogic@0: 	unsigned int base;
lbajardsilogic@0: 	if (type == 0) {
lbajardsilogic@0: 	    base = (1 << power);
lbajardsilogic@0: 	} else {
lbajardsilogic@0: 	    base = (((unsigned int)((1 << minCachePower) * sqrt(2.0) + 0.01))
lbajardsilogic@0: 		    << (power - minCachePower));
lbajardsilogic@0: 	}
lbajardsilogic@0: 
lbajardsilogic@0: //	std::cerr << "Testing base " << base << std::endl;
lbajardsilogic@0: 	if (base >= blockSize) {
lbajardsilogic@0: 	    if (dir == RoundNearest) {
lbajardsilogic@0: 		if (base - blockSize < blockSize - prevBase) {
lbajardsilogic@0: 		    dir = RoundUp;
lbajardsilogic@0: 		} else {
lbajardsilogic@0: 		    dir = RoundDown;
lbajardsilogic@0: 		}
lbajardsilogic@0: 	    }
lbajardsilogic@0: 	    if (dir == RoundUp) {
lbajardsilogic@0: 		result = base;
lbajardsilogic@0: 		break;
lbajardsilogic@0: 	    } else {
lbajardsilogic@0: 		type = prevType;
lbajardsilogic@0: 		power = prevPower;
lbajardsilogic@0: 		result = prevBase;
lbajardsilogic@0: 		break;
lbajardsilogic@0: 	    }
lbajardsilogic@0: 	}
lbajardsilogic@0: 
lbajardsilogic@0: 	prevType = type;
lbajardsilogic@0: 	prevPower = power;
lbajardsilogic@0: 	prevBase = base;
lbajardsilogic@0:     }
lbajardsilogic@0: 
lbajardsilogic@0:     if (result > getMaxZoomLevel()) result = getMaxZoomLevel();
lbajardsilogic@0:     return result;
lbajardsilogic@0: }