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AK: Prevent bit counter underflows in the new BitStream

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Our current `peek_bits` function allows retrieving more bits than we can
actually provide, so whenever someone discards the requested bit count
afterwards we were underflowing the value instead.
This commit is contained in:
Tim Schumacher 2023-04-27 11:33:08 +02:00 • committed by Jelle Raaijmakers
parent dffef6bb71
commit 56d861ebe0
1 changed files with 4 additions and 0 deletions
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4
AK/BitStream.h
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@ -222,6 +222,10 @@ public:
ALWAYS_INLINE void discard_previously_peeked_bits(u8 count) ALWAYS_INLINE void discard_previously_peeked_bits(u8 count)
{ {
// We allow "retrieving" more bits than we can provide, but we need to make sure that we don't underflow the current bit counter.
if (count > m_bit_count)
count = m_bit_count;
m_bit_offset += count; m_bit_offset += count;
m_bit_count -= count; m_bit_count -= count;
} }