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bitwriter.c: Fix undefined behaviour

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Patch-from: lvqcl <lvqcl.mail@gmail.com>
This commit is contained in:
Erik de Castro Lopo 2015-12-20 19:40:27 +11:00
parent 55910e61ac
commit 02a9262e30
1 changed files with 6 additions and 2 deletions
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8
src/libFLAC/bitwriter.c
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@ -410,7 +410,9 @@ unsigned FLAC__bitwriter_rice_bits(FLAC__int32 val, unsigned parameter)
FLAC__ASSERT(parameter < sizeof(unsigned)*8);
/* fold signed to unsigned; actual formula is: negative(v)? -2v-1 : 2v */
uval = (val<<1) ^ (val>>31);
uval = val;
uval <<= 1;
uval ^= (val>>31);
return 1 + parameter + (uval >> parameter);
}
@ -489,7 +491,9 @@ FLAC__bool FLAC__bitwriter_write_rice_signed(FLAC__BitWriter *bw, FLAC__int32 va
FLAC__ASSERT(parameter < 8*sizeof(uval));
/* fold signed to unsigned; actual formula is: negative(v)? -2v-1 : 2v */
uval = (val<<1) ^ (val>>31);
uval = val;
uval <<= 1;
uval ^= (val>>31);
msbs = uval >> parameter;
interesting_bits = 1 + parameter;