astc: OutputBitStream style changes and make it constexpr

This commit is contained in:
ReinUsesLisp 2020-04-09 02:37:51 -03:00
parent 449255675d
commit 0efc230381

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@ -40,17 +40,17 @@ constexpr u32 Popcnt(u32 n) {
class InputBitStream {
public:
explicit InputBitStream(const u8* ptr, std::size_t start_offset = 0)
: m_CurByte(ptr), m_NextBit(start_offset % 8) {}
: cur_byte(ptr), next_bit(start_offset % 8) {}
std::size_t GetBitsRead() const {
return m_BitsRead;
}
u32 ReadBit() {
u32 bit = *m_CurByte >> m_NextBit++;
while (m_NextBit >= 8) {
m_NextBit -= 8;
m_CurByte++;
u32 bit = *cur_byte >> next_bit++;
while (next_bit >= 8) {
next_bit -= 8;
cur_byte++;
}
m_BitsRead++;
@ -75,64 +75,58 @@ public:
}
private:
const u8* m_CurByte;
std::size_t m_NextBit = 0;
const u8* cur_byte;
std::size_t next_bit = 0;
std::size_t m_BitsRead = 0;
};
class OutputBitStream {
public:
explicit OutputBitStream(u8* ptr, s32 nBits = 0, s32 start_offset = 0)
: m_NumBits(nBits), m_CurByte(ptr), m_NextBit(start_offset % 8) {}
constexpr explicit OutputBitStream(u8* ptr, std::size_t bits = 0, std::size_t start_offset = 0)
: cur_byte{ptr}, num_bits{bits}, next_bit{start_offset % 8} {}
~OutputBitStream() = default;
s32 GetBitsWritten() const {
return m_BitsWritten;
constexpr std::size_t GetBitsWritten() const {
return bits_written;
}
void WriteBitsR(u32 val, u32 nBits) {
constexpr void WriteBitsR(u32 val, u32 nBits) {
for (u32 i = 0; i < nBits; i++) {
WriteBit((val >> (nBits - i - 1)) & 1);
}
}
void WriteBits(u32 val, u32 nBits) {
constexpr void WriteBits(u32 val, u32 nBits) {
for (u32 i = 0; i < nBits; i++) {
WriteBit((val >> i) & 1);
}
}
private:
void WriteBit(s32 b) {
if (done)
constexpr void WriteBit(bool b) {
if (bits_written >= num_bits) {
return;
}
const u32 mask = 1 << m_NextBit++;
const u32 mask = 1 << next_bit++;
// clear the bit
*m_CurByte &= static_cast<u8>(~mask);
*cur_byte &= static_cast<u8>(~mask);
// Write the bit, if necessary
if (b)
*m_CurByte |= static_cast<u8>(mask);
*cur_byte |= static_cast<u8>(mask);
// Next byte?
if (m_NextBit >= 8) {
m_CurByte += 1;
m_NextBit = 0;
if (next_bit >= 8) {
cur_byte += 1;
next_bit = 0;
}
}
done = done || ++m_BitsWritten >= m_NumBits;
}
s32 m_BitsWritten = 0;
const s32 m_NumBits;
u8* m_CurByte;
s32 m_NextBit = 0;
bool done = false;
u8* cur_byte;
std::size_t num_bits;
std::size_t bits_written = 0;
std::size_t next_bit = 0;
};
template <typename IntType>