1 /* 2 * Copyright (c) 2011-2015, Intel Corporation 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without modification, 6 * are permitted provided that the following conditions are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright notice, this 9 * list of conditions and the following disclaimer. 10 * 11 * 2. Redistributions in binary form must reproduce the above copyright notice, 12 * this list of conditions and the following disclaimer in the documentation and/or 13 * other materials provided with the distribution. 14 * 15 * 3. Neither the name of the copyright holder nor the names of its contributors 16 * may be used to endorse or promote products derived from this software without 17 * specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 21 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 22 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR 23 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 24 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 26 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 28 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #pragma once 32 33 #include "LinearParameterAdaptation.h" 34 #include <cmath> 35 #include <limits> 36 37 /** 38 * This class is used to perform a logarithmic adapation of type: 39 * (slopeNumerator / slopeDenominator) * log(parameter) + offset 40 * Since log(x) == -INFINITY , we can define FloorValue as a 41 * x -> 0 42 * a lower bound limit for the adaptation 43 */ 44 class CLogarithmicParameterAdaptation : public CLinearParameterAdaptation 45 { 46 public: 47 CLogarithmicParameterAdaptation(); 48 49 /** 50 * Conversions must satisfy the following: f(f'(a)) = a 51 * Let f=fromUserValue and f'=toUserValue 52 * if y = f(log(x)/log(base)), then 53 * f'(y) * log(base) = log (x) 54 * exp(f'(y)*log(base)) = x 55 */ 56 int64_t fromUserValue(double dValue) const override; 57 double toUserValue(int64_t iValue) const override; 58 59 void showProperties(std::string &strResult) const override; 60 61 bool fromXml(const CXmlElement &xmlElement, 62 CXmlSerializingContext &serializingContext) override; 63 64 private: 65 /** 66 * _dLogarithmBase characterizes the new logarithm logB(x) with 67 * the following property: logB(x) = log(x) / log(_dLogarithmBase). 68 * log being the base-e logarithm. 69 * 70 * std::exp(1) == e^1 == e == natural logarithm base 71 * Make sure there is no precision lose by using std::exp overload that 72 * return the same type as _dLogarithmBase 73 */ 74 double _dLogarithmBase{std::exp(decltype(_dLogarithmBase){1})}; 75 /** 76 * _dFloorValue reflects the lower bound for volume attenuation 77 */ 78 double _dFloorValue{-std::numeric_limits<double>::infinity()}; 79 }; 80