Mercurial > hg > octave-jordi
changeset 8193:5fd507839b76
remove the int->real conversion code vulnerability to compiler optimization
| author | Jaroslav Hajek <highegg@gmail.com> |
|---|---|
| date | Wed, 08 Oct 2008 08:01:46 +0200 |
| parents | 9a0a66f650b1 |
| children | aea271e60434 |
| files | liboctave/ChangeLog liboctave/oct-inttypes.h |
| diffstat | 2 files changed, 16 insertions(+), 8 deletions(-) [+] |
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--- a/liboctave/ChangeLog +++ b/liboctave/ChangeLog @@ -1,3 +1,10 @@ +2008-10-08 Jaroslav Hajek <highegg@gmail.com> + + * oct-inttypes.h (octave_base_int<T>::compute_threshold): Return + exclusive bounds rather than inclusive, be resistant to compiler + optimizations. + (octave_base_int<T>::convert_real): Use exclusive bounds. + 2008-10-07 Jaroslav Hajek <highegg@gmail.com> * oct-inttypes.h (OCTAVE_INT_DOUBLE_BIN_OP): Change octave_int64 to
--- a/liboctave/oct-inttypes.h +++ b/liboctave/oct-inttypes.h @@ -267,11 +267,12 @@ static S compute_threshold (S val, T orig_val) { - if (static_cast <T> (val) != orig_val) - return val; - else - // Next number away from zero. - return val * (static_cast<S> (1.0) + std::numeric_limits<S>::epsilon ()); + val = xround (val); // Fool optimizations (maybe redundant) + // If val is even, but orig_val is odd, we're one unit off. + if (orig_val % 2 && val / 2 == xround (val / 2)) + // TODO: is this always correct? + val *= (static_cast<S>(1) - (std::numeric_limits<S>::epsilon () / 2)); + return val; } public: @@ -288,12 +289,12 @@ fnan = true; return static_cast<T> (0); } - else if (value <= thmin) + else if (value < thmin) { - octave_int_base<T>::ftrunc = true; + ftrunc = true; return min_val (); } - else if (value >= thmax) + else if (value > thmax) { ftrunc = true; return max_val ();