// * If aVariantMask is VARIANT_NUMBER, this function parses the
// <number-multiplicative-expression> production.
// * If aVariantMask does not contain VARIANT_NUMBER, this function
// parses the <value-multiplicative-expression> production.
// * Otherwise (VARIANT_NUMBER and other bits) this function parses
// whichever one of the productions matches ***and modifies
// aVariantMask*** to reflect which one it has parsed by either
// removing VARIANT_NUMBER or removing all other bits.
// It does so iteratively, but builds the correct recursive data
// structure.
// This function always consumes *trailing* whitespace when it returns
// true; whether there was any such whitespace is returned in the
// aHadFinalWS parameter.
internal bool ParseCalcMultiplicativeExpression(ref nsCSSValue aValue,
ref int32_t aVariantMask,
ref bool aHadFinalWS)
{
Debug.Assert(aVariantMask != 0, "unexpected variant mask");
bool gotValue = false; // already got the part with the unit
bool afterDivision = false;
nsCSSValue storage = aValue;
for (;;) {
int32_t variantMask = 0;
if (afterDivision || gotValue) {
variantMask = VARIANT_NUMBER;
} else {
variantMask = aVariantMask | VARIANT_NUMBER;
}
if (!ParseCalcTerm(ref storage, ref variantMask))
return false;
Debug.Assert(variantMask != 0,
"ParseCalcTerm did not set variantMask appropriately");
if ((variantMask & VARIANT_NUMBER) != 0) {
// Simplify the value immediately so we can check for division by
// zero.
var ops = new ReduceNumberCalcOps();
float number = CommonUtil.ComputeCalc(storage, ops);
if (number == 0.0 && afterDivision)
return false;
storage.SetFloatValue(number, nsCSSUnit.Number);
} else {
gotValue = true;
if (storage != aValue) {
// Simplify any numbers in the Times_L position (which are
// not simplified by the check above).
Debug.Assert(storage == aValue.GetArrayValue().Item(1),
"unexpected relationship to current storage");
nsCSSValue leftValue = aValue.GetArrayValue().Item(0);
var ops = new ReduceNumberCalcOps();
float number = CommonUtil.ComputeCalc(leftValue, ops);
leftValue.SetFloatValue(number, nsCSSUnit.Number);
}
}
bool hadWS = RequireWhitespace();
if (!GetToken(false)) {
aHadFinalWS = hadWS;
break;
}
nsCSSUnit unit = 0;
if (mToken.IsSymbol('*')) {
unit = gotValue ? nsCSSUnit.CalcTimesR : nsCSSUnit.CalcTimesL;
afterDivision = false;
} else if (mToken.IsSymbol('/')) {
unit = nsCSSUnit.CalcDivided;
afterDivision = true;
} else {
UngetToken();
aHadFinalWS = hadWS;
break;
}
nsCSSValue[] arr = new nsCSSValue[2];
arr[0] = aValue;
storage = arr[1];
aValue.SetArrayValue(arr, unit);
}
// Adjust aVariantMask (see comments above function) to reflect which
// option we took.
if ((aVariantMask & VARIANT_NUMBER) != 0) {
if (gotValue) {
aVariantMask &= ~((int32_t)(VARIANT_NUMBER));
} else {
aVariantMask = VARIANT_NUMBER;
}
} else {
if (!gotValue) {
// We had to find a value, but we didn't.
return false;
}
}
return true;
}