WaveClipUtilities.cpp

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/*  SPDX-License-Identifier: GPL-2.0-or-later */
/*!********************************************************************
 
  Audacity: A Digital Audio Editor
 
  WaveClipUtilities.cpp
 
  Paul Licameli split from WaveClip.cpp
 
**********************************************************************/
#include "WaveClipUtilities.h"
#include "WaveClip.h"
#include <cmath>
 
bool WaveClipUtilities::GetFloatAtTime(const WaveClip &clip,
   double t, size_t iChannel, float& value, bool mayThrow)
{
   if (!clip.WithinPlayRegion(t))
      return false;
   const auto start = clip.TimeToSamples(t);
   return clip.GetSamples(
      iChannel, reinterpret_cast<samplePtr>(&value), floatSample, start, 1u,
      mayThrow);
}
 
void WaveClipUtilities::SetFloatsFromTime(WaveClip &clip,
   double t, size_t iChannel, const float* buffer, size_t numFloats,
   sampleFormat effectiveFormat)
{
   const auto maybeNegativeStart = clip.TimeToSamples(t);
   const auto maybeOutOfBoundEnd = maybeNegativeStart + numFloats;
   const auto effectiveStart = std::max(sampleCount { 0 }, maybeNegativeStart);
   const auto effectiveEnd =
      std::min(clip.GetVisibleSampleCount(), maybeOutOfBoundEnd);
   if (effectiveStart >= effectiveEnd)
      return;
   // Cannot be greater than `numFloats` -> safe cast
   const auto effectiveLen = (effectiveEnd - effectiveStart).as_size_t();
   // Cannot be greater than `numFloats` -> safe cast
   const auto numLeadingZeros =
      (effectiveStart - maybeNegativeStart).as_size_t();
   const auto offsetBuffer =
      reinterpret_cast<const char*>(buffer + numLeadingZeros);
   clip.SetSamples(
      iChannel, offsetBuffer, floatSample, effectiveStart, effectiveLen,
      effectiveFormat);
}
 
bool WaveClipUtilities::SharesBoundaryWithNextClip(
   const WaveTrack::Interval &prev, const WaveTrack::Interval& next)
{
   double endThis = prev.GetRate() * prev.GetPlayStartTime() +
      prev.GetVisibleSampleCount().as_double() * prev.GetStretchRatio();
   double startNext = next.GetRate() * next.GetPlayStartTime();
 
   // given that a double has about 15 significant digits, using a criterion
   // of half a sample should be safe in all normal usage.
   return fabs(startNext - endThis) < 0.5;
}