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PP: floating-point parsing: more stable handling of istringstream::fail

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Possibly addresses #1456
This commit is contained in:
John Kessenich 2018-07-26 14:29:29 -06:00
parent 13803b185d
commit 561a43d272
1 changed files with 8 additions and 3 deletions
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11
glslang/MachineIndependent/preprocessor/PpScanner.cpp
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@ -316,16 +316,21 @@ int TPpContext::lFloatConst(int len, int ch, TPpToken* ppToken)
ppToken->dval = (double)wholeNumber * exponentValue;
} else {
// slow path
ppToken->dval = 0.0;
strtodStream.clear();
strtodStream.str(ppToken->name);
strtodStream >> ppToken->dval;
// Assume failure combined with a large exponent was overflow, in
// an attempt to set INF. Otherwise, assume underflow, and set 0.0.
if (strtodStream.fail()) {
// Assume failure combined with a large exponent was overflow, in
// an attempt to set INF.
if (!negativeExponent && exponent + numWholeNumberDigits > 300)
ppToken->i64val = 0x7ff0000000000000; // +Infinity
else
// Assume failure combined with a small exponent was overflow.
if (negativeExponent && exponent + numWholeNumberDigits > 300)
ppToken->dval = 0.0;
// Unknown reason for failure. Theory is that either
// - the 0.0 is still there, or
// - something reasonable was written that is better than 0.0
}
}