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AK: Simplify BigEndianInputBitStream::read_bits()

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No need to perform extra loop iterations every time we need to read a
new byte. No functional changes.
This commit is contained in:
Jelle Raaijmakers 2026-04-29 09:51:30 +02:00 committed by Jelle Raaijmakers
parent 3ffc75961d
commit 71b0aaa461
1 changed files with 27 additions and 27 deletions
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40
AK/BitStream.h
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@ -60,10 +60,26 @@ public:
size_t nread = 0;
while (nread < count) {
if (m_current_byte.has_value()) {
if constexpr (!IsSame<bool, T> && !IsSame<u8, T>) {
// read as many bytes as possible directly
if (((count - nread) >= 8) && is_aligned_to_byte_boundary()) {
if (!m_current_byte.has_value()) {
m_current_byte = TRY(m_stream->read_value<u8>());
m_bit_offset = 0;
}
if constexpr (IsOneOf<T, bool, u8>) {
// Always take this branch for booleans or u8: there's no purpose in reading more than a single bit.
auto const bit = (m_current_byte.value() >> (7 - m_bit_offset)) & 1;
if constexpr (IsSame<bool, T>) {
result = bit;
} else {
result <<= 1;
result |= bit;
}
++nread;
if (m_bit_offset++ == 7)
m_current_byte.clear();
} else {
// Read as many bits as possible directly.
if ((count - nread >= 8) && is_aligned_to_byte_boundary()) {
// shift existing data over
result <<= 8;
result |= m_current_byte.value();
@ -77,22 +93,6 @@ public:
if (m_bit_offset++ == 7)
m_current_byte.clear();
}
} else {
// Always take this branch for booleans or u8: there's no purpose in reading more than a single bit
auto const bit = (m_current_byte.value() >> (7 - m_bit_offset)) & 1;
if constexpr (IsSame<bool, T>)
result = bit;
else {
result <<= 1;
result |= bit;
}
++nread;
if (m_bit_offset++ == 7)
m_current_byte.clear();
}
} else {
m_current_byte = TRY(m_stream->read_value<u8>());
m_bit_offset = 0;
}
}