/*
 * Computes the total distance to be travelled by a paced animation.
 *
 * Returns the total distance, or returns COMPUTE_DISTANCE_ERROR if
 * our values don't support distance computation.
 */
double
nsSMILAnimationFunction::ComputePacedTotalDistance(
    const nsSMILValueArray& aValues) const
{
  NS_ASSERTION(GetCalcMode() == CALC_PACED,
               "Calling paced-specific function, but not in paced mode");

  double totalDistance = 0.0;
  for (PRUint32 i = 0; i < aValues.Length() - 1; i++) {
    double tmpDist;
    nsresult rv = aValues[i].ComputeDistance(aValues[i+1], tmpDist);
    if (NS_FAILED(rv)) {
      return COMPUTE_DISTANCE_ERROR;
    }

    // Clamp distance value to 0, just in case we have an evil ComputeDistance
    // implementation somewhere
    NS_ABORT_IF_FALSE(tmpDist >= 0.0f, "distance values must be non-negative");
    tmpDist = NS_MAX(tmpDist, 0.0);

    totalDistance += tmpDist;
  }

  return totalDistance;
}

nsresult
nsSMILAnimationFunction::AccumulateResult(const nsSMILValueArray& aValues,
                                          nsSMILValue& aResult)
{
  if (!IsToAnimation() && GetAccumulate() && mRepeatIteration) {
    const nsSMILValue& lastValue = aValues[aValues.Length() - 1];

    // If the target attribute type doesn't support addition, Add will
    // fail and we leave aResult untouched.
    aResult.Add(lastValue, mRepeatIteration);
  }

  return NS_OK;
}

bool
SVGMotionSMILAnimationFunction::
  GenerateValuesForPathAndPoints(Path* aPath,
                                 bool aIsKeyPoints,
                                 FallibleTArray<double>& aPointDistances,
                                 nsSMILValueArray& aResult)
{
  MOZ_ASSERT(aResult.IsEmpty(), "outparam is non-empty");

  // If we're using "keyPoints" as our list of input distances, then we need
  // to de-normalize from the [0, 1] scale to the [0, totalPathLen] scale.
  double distanceMultiplier = aIsKeyPoints ? aPath->ComputeLength() : 1.0;
  const uint32_t numPoints = aPointDistances.Length();
  for (uint32_t i = 0; i < numPoints; ++i) {
    double curDist = aPointDistances[i] * distanceMultiplier;
    if (!aResult.AppendElement(
          SVGMotionSMILType::ConstructSMILValue(aPath, curDist,
                                                mRotateType, mRotateAngle))) {
      return false;
    }
  }
  return true;
}

/*
 * Given the simple progress for a paced animation, this method:
 *  - determines which two elements of the values array we're in between
 *    (returned as aFrom and aTo)
 *  - determines where we are between them
 *    (returned as aIntervalProgress)
 *
 * Returns NS_OK, or NS_ERROR_FAILURE if our values don't support distance
 * computation.
 */
nsresult
nsSMILAnimationFunction::ComputePacedPosition(const nsSMILValueArray& aValues,
                                              double aSimpleProgress,
                                              double& aIntervalProgress,
                                              const nsSMILValue*& aFrom,
                                              const nsSMILValue*& aTo)
{
  NS_ASSERTION(0.0f <= aSimpleProgress && aSimpleProgress < 1.0f,
               "aSimpleProgress is out of bounds");
  NS_ASSERTION(GetCalcMode() == CALC_PACED,
               "Calling paced-specific function, but not in paced mode");
  NS_ABORT_IF_FALSE(aValues.Length() >= 2, "Unexpected number of values");

  // Trivial case: If we have just 2 values, then there's only one interval
  // for us to traverse, and our progress across that interval is the exact
  // same as our overall progress.
  if (aValues.Length() == 2) {
    aIntervalProgress = aSimpleProgress;
    aFrom = &aValues[0];
    aTo = &aValues[1];
    return NS_OK;
  }

  double totalDistance = ComputePacedTotalDistance(aValues);
  if (totalDistance == COMPUTE_DISTANCE_ERROR)
    return NS_ERROR_FAILURE;

  // total distance we should have moved at this point in time.
  // (called 'remainingDist' due to how it's used in loop below)
  double remainingDist = aSimpleProgress * totalDistance;

  // Must be satisfied, because totalDistance is a sum of (non-negative)
  // distances, and aSimpleProgress is non-negative
  NS_ASSERTION(remainingDist >= 0, "distance values must be non-negative");

  // Find where remainingDist puts us in the list of values
  // Note: We could optimize this next loop by caching the
  // interval-distances in an array, but maybe that's excessive.
  for (PRUint32 i = 0; i < aValues.Length() - 1; i++) {
    // Note: The following assertion is valid because remainingDist should
    // start out non-negative, and this loop never shaves off more than its
    // current value.
    NS_ASSERTION(remainingDist >= 0, "distance values must be non-negative");

    double curIntervalDist;
    nsresult rv = aValues[i].ComputeDistance(aValues[i+1], curIntervalDist);
    NS_ABORT_IF_FALSE(NS_SUCCEEDED(rv),
                      "If we got through ComputePacedTotalDistance, we should "
                      "be able to recompute each sub-distance without errors");

    NS_ASSERTION(curIntervalDist >= 0, "distance values must be non-negative");
    // Clamp distance value at 0, just in case ComputeDistance is evil.
    curIntervalDist = NS_MAX(curIntervalDist, 0.0);

    if (remainingDist >= curIntervalDist) {
      remainingDist -= curIntervalDist;
    } else {
      // NOTE: If we get here, then curIntervalDist necessarily is not 0. Why?
      // Because this clause is only hit when remainingDist < curIntervalDist,
      // and if curIntervalDist were 0, that would mean remainingDist would
      // have to be < 0.  But that can't happen, because remainingDist (as
      // a distance) is non-negative by definition.
      NS_ASSERTION(curIntervalDist != 0,
                   "We should never get here with this set to 0...");

      // We found the right spot -- an interpolated position between
      // values i and i+1.
      aFrom = &aValues[i];
      aTo = &aValues[i+1];
      aIntervalProgress = remainingDist / curIntervalDist;
      return NS_OK;
    }
  }

  NS_NOTREACHED("shouldn't complete loop & get here -- if we do, "
                "then aSimpleProgress was probably out of bounds");
  return NS_ERROR_FAILURE;
}

nsresult
nsSMILAnimationFunction::InterpolateResult(const nsSMILValueArray& aValues,
                                           nsSMILValue& aResult,
                                           nsSMILValue& aBaseValue)
{
  nsresult rv = NS_OK;
  const nsSMILTime& dur = mSimpleDuration.GetMillis();

  // Sanity Checks
  NS_ABORT_IF_FALSE(mSampleTime >= 0.0f, "Sample time should not be negative");
  NS_ABORT_IF_FALSE(dur >= 0.0f, "Simple duration should not be negative");

  if (mSampleTime >= dur || mSampleTime < 0.0f) {
    NS_ERROR("Animation sampled outside interval");
    return NS_ERROR_FAILURE;
  }

  if ((!IsToAnimation() && aValues.Length() < 2) ||
      (IsToAnimation()  && aValues.Length() != 1)) {
    NS_ERROR("Unexpected number of values");
    return NS_ERROR_FAILURE;
  }
  // End Sanity Checks

  double fTime = double(mSampleTime);
  double fDur = double(dur);

  // Get the normalised progress through the simple duration
  double simpleProgress = (fDur > 0.0) ? fTime / fDur : 0.0;

  // Handle bad keytimes (where first != 0 and/or last != 1)
  // See http://brian.sol1.net/svg/range-for-keytimes for more info.
  if (HasAttr(nsGkAtoms::keyTimes) &&
      GetCalcMode() != CALC_PACED) {
    double first = mKeyTimes[0];
    if (first > 0.0 && simpleProgress < first) {
      if (!IsToAnimation())
        aResult = aValues[0];
      return rv;
    }
    double last = mKeyTimes[mKeyTimes.Length() - 1];
    if (last < 1.0 && simpleProgress >= last) {
      if (IsToAnimation())
        aResult = aValues[0];
      else
        aResult = aValues[aValues.Length() - 1];
      return rv;
    }
  }

  if (GetCalcMode() != CALC_DISCRETE) {
    // Get the normalised progress between adjacent values
    const nsSMILValue* from = nsnull;
    const nsSMILValue* to = nsnull;
    double intervalProgress;
    if (IsToAnimation()) {
      from = &aBaseValue;
      to = &aValues[0];
      if (GetCalcMode() == CALC_PACED) {
        // Note: key[Times/Splines/Points] are ignored for calcMode="paced"
        intervalProgress = simpleProgress;
      } else {
        ScaleSimpleProgress(simpleProgress);
        intervalProgress = simpleProgress;
        ScaleIntervalProgress(intervalProgress, 0, 1);
      }
    } else {
      if (GetCalcMode() == CALC_PACED) {
        rv = ComputePacedPosition(aValues, simpleProgress,
                                  intervalProgress, from, to);
        // Note: If the above call fails, we'll skip the "from->Interpolate"
        // call below, and we'll drop into the CALC_DISCRETE section
        // instead. (as the spec says we should, because our failure was
        // presumably due to the values being non-additive)
      } else { // GetCalcMode() == CALC_LINEAR or GetCalcMode() == CALC_SPLINE
        ScaleSimpleProgress(simpleProgress);
        PRUint32 index = (PRUint32)floor(simpleProgress *
                                         (aValues.Length() - 1));
        from = &aValues[index];
        to = &aValues[index + 1];
        intervalProgress = simpleProgress * (aValues.Length() - 1) - index;
        ScaleIntervalProgress(intervalProgress, index, aValues.Length() - 1);
      }
    }
    if (NS_SUCCEEDED(rv)) {
      NS_ABORT_IF_FALSE(from, "NULL from-value during interpolation");
      NS_ABORT_IF_FALSE(to, "NULL to-value during interpolation");
      NS_ABORT_IF_FALSE(0.0f <= intervalProgress && intervalProgress < 1.0f,
                      "Interval progress should be in the range [0, 1)");
      rv = from->Interpolate(*to, intervalProgress, aResult);
    }
  }

  // Discrete-CalcMode case
  // Note: If interpolation failed (isn't supported for this type), the SVG
  // spec says to force discrete mode.
  if (GetCalcMode() == CALC_DISCRETE || NS_FAILED(rv)) {
    if (IsToAnimation()) {
      // SMIL 3, 12.6.4: Since a to animation has only 1 value, a discrete to
      // animation will simply set the to value for the simple duration.
//.........这里部分代码省略.........

nsresult
nsSMILAnimationFunction::InterpolateResult(const nsSMILValueArray& aValues,
                                           nsSMILValue& aResult,
                                           nsSMILValue& aBaseValue)
{
  // Sanity check animation values
  if ((!IsToAnimation() && aValues.Length() < 2) ||
      (IsToAnimation()  && aValues.Length() != 1)) {
    NS_ERROR("Unexpected number of values");
    return NS_ERROR_FAILURE;
  }

  if (IsToAnimation() && aBaseValue.IsNull()) {
    return NS_ERROR_FAILURE;
  }

  // Get the normalised progress through the simple duration.
  //
  // If we have an indefinite simple duration, just set the progress to be
  // 0 which will give us the expected behaviour of the animation being fixed at
  // its starting point.
  double simpleProgress = 0.0;

  if (mSimpleDuration.IsDefinite()) {
    nsSMILTime dur = mSimpleDuration.GetMillis();

    MOZ_ASSERT(dur >= 0, "Simple duration should not be negative");
    MOZ_ASSERT(mSampleTime >= 0, "Sample time should not be negative");

    if (mSampleTime >= dur || mSampleTime < 0) {
      NS_ERROR("Animation sampled outside interval");
      return NS_ERROR_FAILURE;
    }

    if (dur > 0) {
      simpleProgress = (double)mSampleTime / dur;
    } // else leave simpleProgress at 0.0 (e.g. if mSampleTime == dur == 0)
  }

  nsresult rv = NS_OK;
  nsSMILCalcMode calcMode = GetCalcMode();

  // Force discrete calcMode for visibility since StyleAnimationValue will
  // try to interpolate it using the special clamping behavior defined for
  // CSS.
  if (nsSMILCSSValueType::PropertyFromValue(aValues[0])
        == eCSSProperty_visibility) {
    calcMode = CALC_DISCRETE;
  }

  if (calcMode != CALC_DISCRETE) {
    // Get the normalised progress between adjacent values
    const nsSMILValue* from = nullptr;
    const nsSMILValue* to = nullptr;
    // Init to -1 to make sure that if we ever forget to set this, the
    // MOZ_ASSERT that tests that intervalProgress is in range will fail.
    double intervalProgress = -1.f;
    if (IsToAnimation()) {
      from = &aBaseValue;
      to = &aValues[0];
      if (calcMode == CALC_PACED) {
        // Note: key[Times/Splines/Points] are ignored for calcMode="paced"
        intervalProgress = simpleProgress;
      } else {
        double scaledSimpleProgress =
          ScaleSimpleProgress(simpleProgress, calcMode);
        intervalProgress = ScaleIntervalProgress(scaledSimpleProgress, 0);
      }
    } else if (calcMode == CALC_PACED) {
      rv = ComputePacedPosition(aValues, simpleProgress,
                                intervalProgress, from, to);
      // Note: If the above call fails, we'll skip the "from->Interpolate"
      // call below, and we'll drop into the CALC_DISCRETE section
      // instead. (as the spec says we should, because our failure was
      // presumably due to the values being non-additive)
    } else { // calcMode == CALC_LINEAR or calcMode == CALC_SPLINE
      double scaledSimpleProgress =
        ScaleSimpleProgress(simpleProgress, calcMode);
      uint32_t index = (uint32_t)floor(scaledSimpleProgress *
                                       (aValues.Length() - 1));
      from = &aValues[index];
      to = &aValues[index + 1];
      intervalProgress =
        scaledSimpleProgress * (aValues.Length() - 1) - index;
      intervalProgress = ScaleIntervalProgress(intervalProgress, index);
    }

    if (NS_SUCCEEDED(rv)) {
      MOZ_ASSERT(from, "NULL from-value during interpolation");
      MOZ_ASSERT(to, "NULL to-value during interpolation");
      MOZ_ASSERT(0.0f <= intervalProgress && intervalProgress < 1.0f,
                 "Interval progress should be in the range [0, 1)");
      rv = from->Interpolate(*to, intervalProgress, aResult);
    }
  }

  // Discrete-CalcMode case
  // Note: If interpolation failed (isn't supported for this type), the SVG
  // spec says to force discrete mode.
  if (calcMode == CALC_DISCRETE || NS_FAILED(rv)) {
//.........这里部分代码省略.........

nsresult
nsSMILAnimationFunction::InterpolateResult(const nsSMILValueArray& aValues,
                                           nsSMILValue& aResult,
                                           nsSMILValue& aBaseValue)
{
  // Sanity check animation values
  if ((!IsToAnimation() && aValues.Length() < 2) ||
      (IsToAnimation()  && aValues.Length() != 1)) {
    NS_ERROR("Unexpected number of values");
    return NS_ERROR_FAILURE;
  }

  if (IsToAnimation() && aBaseValue.IsNull()) {
    return NS_ERROR_FAILURE;
  }

  // Get the normalised progress through the simple duration.
  //
  // If we have an indefinite simple duration, just set the progress to be
  // 0 which will give us the expected behaviour of the animation being fixed at
  // its starting point.
  double simpleProgress = 0.0;

  if (mSimpleDuration.IsResolved()) {
    nsSMILTime dur = mSimpleDuration.GetMillis();

    NS_ABORT_IF_FALSE(dur >= 0, "Simple duration should not be negative");
    NS_ABORT_IF_FALSE(mSampleTime >= 0, "Sample time should not be negative");

    if (mSampleTime >= dur || mSampleTime < 0) {
      NS_ERROR("Animation sampled outside interval");
      return NS_ERROR_FAILURE;
    }

    if (dur > 0) {
      simpleProgress = (double)mSampleTime / dur;
    } // else leave simpleProgress at 0.0 (e.g. if mSampleTime == dur == 0)
  }

  nsresult rv = NS_OK;
  nsSMILCalcMode calcMode = GetCalcMode();
  if (calcMode != CALC_DISCRETE) {
    // Get the normalised progress between adjacent values
    const nsSMILValue* from = nsnull;
    const nsSMILValue* to = nsnull;
    // Init to -1 to make sure that if we ever forget to set this, the
    // NS_ABORT_IF_FALSE that tests that intervalProgress is in range will fail.
    double intervalProgress = -1.f;
    if (IsToAnimation()) {
      from = &aBaseValue;
      to = &aValues[0];
      if (calcMode == CALC_PACED) {
        // Note: key[Times/Splines/Points] are ignored for calcMode="paced"
        intervalProgress = simpleProgress;
      } else {
        double scaledSimpleProgress =
          ScaleSimpleProgress(simpleProgress, calcMode);
        intervalProgress = ScaleIntervalProgress(scaledSimpleProgress, 0);
      }
    } else if (calcMode == CALC_PACED) {
      rv = ComputePacedPosition(aValues, simpleProgress,
                                intervalProgress, from, to);
      // Note: If the above call fails, we'll skip the "from->Interpolate"
      // call below, and we'll drop into the CALC_DISCRETE section
      // instead. (as the spec says we should, because our failure was
      // presumably due to the values being non-additive)
    } else { // calcMode == CALC_LINEAR or calcMode == CALC_SPLINE
      double scaledSimpleProgress =
        ScaleSimpleProgress(simpleProgress, calcMode);
      PRUint32 index = (PRUint32)floor(scaledSimpleProgress *
                                       (aValues.Length() - 1));
      from = &aValues[index];
      to = &aValues[index + 1];
      intervalProgress =
        scaledSimpleProgress * (aValues.Length() - 1) - index;
      intervalProgress = ScaleIntervalProgress(intervalProgress, index);
    }

    if (NS_SUCCEEDED(rv)) {
      NS_ABORT_IF_FALSE(from, "NULL from-value during interpolation");
      NS_ABORT_IF_FALSE(to, "NULL to-value during interpolation");
      NS_ABORT_IF_FALSE(0.0f <= intervalProgress && intervalProgress < 1.0f,
                      "Interval progress should be in the range [0, 1)");
      rv = from->Interpolate(*to, intervalProgress, aResult);
    }
  }

  // Discrete-CalcMode case
  // Note: If interpolation failed (isn't supported for this type), the SVG
  // spec says to force discrete mode.
  if (calcMode == CALC_DISCRETE || NS_FAILED(rv)) {
    double scaledSimpleProgress =
      ScaleSimpleProgress(simpleProgress, CALC_DISCRETE);
    if (IsToAnimation()) {
      // We don't follow SMIL 3, 12.6.4, where discrete to animations
      // are the same as <set> animations.  Instead, we treat it as a
      // discrete animation with two values (the underlying value and
      // the to="" value), and honor keyTimes="" as well.
      PRUint32 index = (PRUint32)floor(scaledSimpleProgress * 2);
      aResult = index == 0 ? aBaseValue : aValues[0];
//.........这里部分代码省略.........