EchoBase.cpp

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/**********************************************************************
 
  Audacity: A Digital Audio Editor
 
  EchoBase.cpp
 
  Dominic Mazzoni
  Vaughan Johnson (dialog)
 
***********************************************************************/
#include "EchoBase.h"
#include "BasicUI.h"
#include "ShuttleAutomation.h"
 
const EffectParameterMethods& EchoBase::Parameters() const
{
   static CapturedParameters<EchoBase, Delay, Decay> parameters;
   return parameters;
}
 
const ComponentInterfaceSymbol EchoBase::Symbol { XO("Echo") };
 
EchoBase::EchoBase()
{
   SetLinearEffectFlag(true);
}
 
EchoBase::~EchoBase()
{
}
 
// ComponentInterface implementation
 
ComponentInterfaceSymbol EchoBase::GetSymbol() const
{
   return Symbol;
}
 
TranslatableString EchoBase::GetDescription() const
{
   return XO("Repeats the selected audio again and again");
}
 
ManualPageID EchoBase::ManualPage() const
{
   return L"Echo";
}
 
// EffectDefinitionInterface implementation
 
EffectType EchoBase::GetType() const
{
   return EffectTypeProcess;
}
 
bool EchoBase::Instance::ProcessInitialize(
   EffectSettings& settings, double sampleRate, ChannelNames)
{
   auto& echoSettings = GetSettings(settings);
   if (echoSettings.delay == 0.0)
      return false;
 
   histPos = 0;
   auto requestedHistLen = (sampleCount)(sampleRate * echoSettings.delay);
 
   // Guard against extreme delay values input by the user
   try
   {
      // Guard against huge delay values from the user.
      // Don't violate the assertion in as_size_t
      if (
         requestedHistLen !=
         (histLen = static_cast<size_t>(requestedHistLen.as_long_long())))
         throw std::bad_alloc {};
      history.reinit(histLen, true);
   }
   catch (const std::bad_alloc&)
   {
      BasicUI::ShowMessageBox(XO("Requested value exceeds memory capacity."));
      return false;
   }
 
   return history != NULL;
}
 
bool EchoBase::Instance::ProcessFinalize() noexcept
{
   return true;
}
 
size_t EchoBase::Instance::ProcessBlock(
   EffectSettings& settings, const float* const* inBlock,
   float* const* outBlock, size_t blockLen)
{
   auto& echoSettings = GetSettings(settings);
 
   const float* ibuf = inBlock[0];
   float* obuf = outBlock[0];
 
   for (decltype(blockLen) i = 0; i < blockLen; i++, histPos++)
   {
      if (histPos == histLen)
      {
         histPos = 0;
      }
      history[histPos] = obuf[i] =
         ibuf[i] + history[histPos] * echoSettings.decay;
   }
 
   return blockLen;
}