Fix int mask sign extension in BitField long methods#1711
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garydgregory
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| public BitField(final int mask) { | ||
| this.mask = mask; | ||
| this.mask = Integer.toUnsignedLong(mask); | ||
| this.shiftCount = mask == 0 ? 0 : Integer.numberOfTrailingZeros(mask); |
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Hello @alhudz
Thank you for the PR.
Should the argument to numberOfTrailingZeros be mask or this.mask?
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Repro:
new BitField(0x80000000), thengetRawValue(-1L)/clear(-1L).Expected:
getRawValue(-1L)==0x80000000andclear(-1L)==0xFFFFFFFF7FFFFFFF, since only bit 31 belongs to the field.Actual:
getRawValue(-1L)==0xFFFFFFFF80000000andclear(-1L)==0x7FFFFFFF, so bits 32-63 leak into the field.Cause: the
long maskfield and the long-typed methods arrived in 3.21.0, butBitField(int)still assigns the int mask straight into thelongfield, so any mask with bit 31 set is sign-extended across bits 32-63. The int-typed methods cast back tointand hide it, the long ones do not.Fix: build the field with
Integer.toUnsignedLong(mask)so the int mask only occupies the low 32 bits.