static void
InitializeTrackSize(nscoord aPercentageBasis,
                    const nsStyleCoord& aMinCoord,
                    const nsStyleCoord& aMaxCoord,
                    TrackSize* aTrackSize)
{
  // http://dev.w3.org/csswg/css-grid/#algo-init
  nscoord& base = aTrackSize->mBase;
  switch (aMaxCoord.GetUnit()) {
    case eStyleUnit_Enumerated:
    case eStyleUnit_FlexFraction:
      base = 0;
      break;
    default:
      base = nsRuleNode::ComputeCoordPercentCalc(aMinCoord, aPercentageBasis);
  }
  nscoord& limit = aTrackSize->mLimit;
  switch (aMaxCoord.GetUnit()) {
    case eStyleUnit_Enumerated:
      limit = NS_UNCONSTRAINEDSIZE;
      break;
    case eStyleUnit_FlexFraction:
      limit = base;
      break;
    default:
      limit = nsRuleNode::ComputeCoordPercentCalc(aMaxCoord, aPercentageBasis);
      if (limit < base) {
        limit = base;
      }
  }
}

static inline PRBool
IsMarginZero(nsStyleUnit aUnit, const nsStyleCoord &aCoord)
{
    return (aUnit == eStyleUnit_Auto ||
            (aUnit == eStyleUnit_Coord && aCoord.GetCoordValue() == 0) ||
            (aUnit == eStyleUnit_Percent && aCoord.GetPercentValue() == 0.0));
}

PRBool
nsIBox::AddCSSMaxSize(nsIBox* aBox, nsSize& aSize, PRBool &aWidthSet, PRBool &aHeightSet)
{
    aWidthSet = PR_FALSE;
    aHeightSet = PR_FALSE;

    // add in the css min, max, pref
    const nsStylePosition* position = aBox->GetStylePosition();

    // and max
    // see if the width or height was specifically set
    // XXX Handle eStyleUnit_Enumerated?
    // (Handling the eStyleUnit_Enumerated types requires
    // GetPrefSize/GetMinSize methods that don't consider
    // (min-/max-/)(width/height) properties.)
    const nsStyleCoord maxWidth = position->mMaxWidth;
    if (maxWidth.ConvertsToLength()) {
        aSize.width = nsRuleNode::ComputeCoordPercentCalc(maxWidth, 0);
        aWidthSet = PR_TRUE;
    }
    // percentages and calc() with percentages are treated like 'none'

    const nsStyleCoord &maxHeight = position->mMaxHeight;
    if (maxHeight.ConvertsToLength()) {
        aSize.height = nsRuleNode::ComputeCoordPercentCalc(maxHeight, 0);
        aHeightSet = PR_TRUE;
    }
    // percentages and calc() with percentages are treated like 'none'

    nsIContent* content = aBox->GetContent();
    if (content) {
        nsAutoString value;
        PRInt32 error;

        content->GetAttr(kNameSpaceID_None, nsGkAtoms::maxwidth, value);
        if (!value.IsEmpty()) {
            value.Trim("%");

            nscoord val =
              nsPresContext::CSSPixelsToAppUnits(value.ToInteger(&error));
            aSize.width = val;
            aWidthSet = PR_TRUE;
        }

        content->GetAttr(kNameSpaceID_None, nsGkAtoms::maxheight, value);
        if (!value.IsEmpty()) {
            value.Trim("%");

            nscoord val =
              nsPresContext::CSSPixelsToAppUnits(value.ToInteger(&error));
            aSize.height = val;

            aHeightSet = PR_TRUE;
        }
    }

    return (aWidthSet || aHeightSet);
}

bool nsStyleCoord::operator==(const nsStyleCoord& aOther) const
{
  if (mUnit != aOther.mUnit) {
    return false;
  }
  switch (mUnit) {
    case eStyleUnit_Null:
    case eStyleUnit_Normal:
    case eStyleUnit_Auto:
    case eStyleUnit_None:
      return true;
    case eStyleUnit_Percent:
    case eStyleUnit_Factor:
    case eStyleUnit_Degree:
    case eStyleUnit_Grad:
    case eStyleUnit_Radian:
    case eStyleUnit_Turn:
      return mValue.mFloat == aOther.mValue.mFloat;
    case eStyleUnit_Coord:
    case eStyleUnit_Integer:
    case eStyleUnit_Enumerated:
      return mValue.mInt == aOther.mValue.mInt;
    case eStyleUnit_Calc:
      return *this->GetCalcValue() == *aOther.GetCalcValue();
  }
  NS_ABORT_IF_FALSE(false, "unexpected unit");
  return false;
}

float
SVGContentUtils::CoordToFloat(nsSVGElement *aContent,
                              const nsStyleCoord &aCoord)
{
    switch (aCoord.GetUnit()) {
    case eStyleUnit_Factor:
        // user units
        return aCoord.GetFactorValue();

    case eStyleUnit_Coord:
        return nsPresContext::AppUnitsToFloatCSSPixels(aCoord.GetCoordValue());

    case eStyleUnit_Percent: {
        SVGSVGElement* ctx = aContent->GetCtx();
        return ctx ? aCoord.GetPercentValue() * ctx->GetLength(SVGContentUtils::XY) : 0.0f;
    }
    default:
        return 0.0f;
    }
}

static inline bool IsFixedOffset(const nsStyleCoord& aCoord)
  { return aCoord.ConvertsToLength(); }

static inline bool IsFixedMarginSize(const nsStyleCoord& aCoord)
  { return aCoord.ConvertsToLength(); }

static inline bool
IsMarginZero(const nsStyleCoord &aCoord)
{
  return aCoord.GetUnit() == eStyleUnit_Auto ||
         nsLayoutUtils::IsMarginZero(aCoord);
}