juce_Decibels.h

/*
  ==============================================================================
 
   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited
 
   JUCE is an open source library subject to commercial or open-source
   licensing.
 
   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.
 
   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.
 
  ==============================================================================
*/
 
namespace juce
{
 
//==============================================================================
class Decibels
{
public:
    //==============================================================================
    template <typename Type>
    static Type decibelsToGain (Type decibels,
                                Type minusInfinityDb = Type (defaultMinusInfinitydB))
    {
        return decibels > minusInfinityDb ? std::pow (Type (10.0), decibels * Type (0.05))
                                          : Type();
    }

    template <typename Type>
    static Type gainToDecibels (Type gain,
                                Type minusInfinityDb = Type (defaultMinusInfinitydB))
    {
        return gain > Type() ? jmax (minusInfinityDb, static_cast<Type> (std::log10 (gain)) * Type (20.0))
                             : minusInfinityDb;
    }

    template <typename Type>
    static Type gainWithLowerBound (Type gain, Type lowerBoundDb)
    {
        // You probably want to use a negative decibel value or the gain will
        // be restricted to boosting only!
        jassert (lowerBoundDb < (Type) 0.0);
 
        return jmax ((Type) gain, Decibels::decibelsToGain (lowerBoundDb, lowerBoundDb - (Type) 1.0));
    }
 
    //==============================================================================
    template <typename Type>
    static String toString (Type decibels,
                            int decimalPlaces = 2,
                            Type minusInfinityDb = Type (defaultMinusInfinitydB),
                            bool shouldIncludeSuffix = true,
                            StringRef customMinusInfinityString = {})
    {
        String s;
        s.preallocateBytes (20);
 
        if (decibels <= minusInfinityDb)
        {
            if (customMinusInfinityString.isEmpty())
                s << "-INF";
            else
                s << customMinusInfinityString;
        }
        else
        {
            if (decibels >= Type())
                s << '+';
 
            if (decimalPlaces <= 0)
                s << roundToInt (decibels);
            else
                s << String (decibels, decimalPlaces);
        }
 
        if (shouldIncludeSuffix)
            s << " dB";
 
        return s;
    }
 
private:
    //==============================================================================
    enum { defaultMinusInfinitydB = -100 };
 
    Decibels() = delete; // This class can't be instantiated, it's just a holder for static methods..
};
 
} // namespace juce