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Fixed BitArray find returning runs that overlap set bits, and missing existing runs. (#459)

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This commit is contained in:
Branimir Karadžić
2026-10-15 09:45:32 -07:00
committed by GitHub
parent d4e6ed3cf4
commit a361ff7878
2 changed files with 142 additions and 61 deletions
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92
src/bitarray.cpp
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@@ -472,13 +472,12 @@ namespace bx
}
template<typename Ty>
inline uint32_t bitSetFindT(const uint64_t* _ptr, uint32_t _beginBit, uint32_t _endBit, uint32_t _numSteps)
inline uint32_t bitSetFindT(const uint64_t* _ptr, uint32_t _beginBit, uint32_t _endBit, uint32_t _numBits)
{
const Ty* bits = (const Ty*)_ptr;
constexpr uint32_t numBitsPerStep = sizeof(Ty)*8;
const uint32_t numBits = _numSteps*numBitsPerStep;
for (uint32_t ii = _beginBit/numBitsPerStep, end = alignUp(_endBit, numBitsPerStep)/numBitsPerStep; ii < end; ++ii)
for (uint32_t ii = alignUp(_beginBit, numBitsPerStep)/numBitsPerStep, end = alignUp(_endBit, numBitsPerStep)/numBitsPerStep; ii < end; ++ii)
{
if (bits[ii] != Ty(0) )
{
@@ -499,7 +498,7 @@ namespace bx
for (++ii; ii < end; ++ii)
{
if (num >= numBits)
if (num >= _numBits)
{
return idx;
}
@@ -514,7 +513,7 @@ namespace bx
}
}
if (num >= numBits)
if (num >= _numBits)
{
return idx;
}
@@ -538,6 +537,7 @@ namespace bx
if (0xff == test)
{
lz = 0;
continue;
}
@@ -553,7 +553,8 @@ namespace bx
const uint32_t idx = pos + 8;
const uint32_t newIdx = max(idx - lz, _beginBit);
lz = min(idx, _endBit) - newIdx;
const uint32_t endIdx = min(idx, _endBit);
lz = endIdx > newIdx ? endIdx - newIdx : 0;
if (lz >= _numBits)
{
@@ -629,70 +630,39 @@ namespace bx
return bitSetFindZero(_ptr, _beginBit, _endBit);
}
// Run of 2*N-1 or more zero bits always contains whole N-bit aligned zero word.
uint32_t idx;
if (_numBits >= 127)
{
const uint32_t idx = bitSetFindT<uint64_t>(_ptr, _beginBit, _endBit, (_numBits+63)>>6);
if (idx != _endBit)
idx = bitSetFindT<uint64_t>(_ptr, _beginBit, _endBit, _numBits);
}
else if (_numBits >= 63)
{
idx = bitSetFindT<uint32_t>(_ptr, _beginBit, _endBit, _numBits);
}
else if (_numBits >= 31)
{
idx = bitSetFindT<uint16_t>(_ptr, _beginBit, _endBit, _numBits);
}
else
{
idx = bitSetFindT<uint8_t>(_ptr, _beginBit, _endBit, _numBits);
if (idx == _endBit
&& _numBits < 15)
{
return idx;
}
}
idx = bitSetFindUpto14(_ptr, _beginBit, _endBit, _numBits);
if (_numBits >= 63)
{
const uint32_t idx = bitSetFindT<uint32_t>(_ptr, _beginBit, _endBit, (_numBits+31)>>5);
if (idx != _endBit)
{
return idx;
}
}
if (_numBits >= 128)
{
return kInvalid;
}
if (_numBits >= 31)
{
const uint32_t idx = bitSetFindT<uint16_t>(_ptr, _beginBit, _endBit, (_numBits+15)>>4);
if (idx != _endBit)
{
return idx;
}
}
if (_numBits >= 64)
{
return kInvalid;
}
uint32_t idx = bitSetFindT<uint8_t>(_ptr, _beginBit, _endBit, (_numBits+7)>>3);
if (idx != _endBit)
{
return idx;
}
if (_numBits < 15)
{
idx = bitSetFindUpto14(_ptr, _beginBit, _endBit, _numBits);
if (idx != _endBit)
{
return idx;
}
if (_numBits < 7)
{
idx = bitSetFindUpto6(_ptr, _beginBit, _endBit, _numBits);
if (idx != _endBit)
if (idx == _endBit
&& _numBits < 7)
{
return idx;
idx = bitSetFindUpto6(_ptr, _beginBit, _endBit, _numBits);
}
}
}
return kInvalid;
return idx != _endBit ? idx : kInvalid;
}
uint64_t BitArrayViewBase::get(uint32_t _beginBit, uint32_t _endBit) const