Class BitReader

publication/source_code/include/chimp/bit_reader.hpp:10–150

//! Within a byte we need to mask off the bits that we're interested in

struct BitReader {
private:
	//! Align the masks to the right
	static constexpr uint8_t MASKS[] = {
	    0,   // 0b00000000,
	    128, // 0b10000000,
	    192, // 0b11000000,
	    224, // 0b11100000,
	    240, // 0b11110000,
	    248, // 0b11111000,
	    252, // 0b11111100,
	    254, // 0b11111110,
	    255, // 0b11111111,
	    // These later masks are for the cases where index + SIZE exceeds 8
	    254, // 0b11111110,
	    252, // 0b11111100,
	    248, // 0b11111000,
	    240, // 0b11110000,
	    224, // 0b11100000,
	    192, // 0b11000000,
	    128, // 0b10000000,
	};

	static constexpr uint8_t REMAINDER_MASKS[] = {
	    0,
	    0,
	    0,
	    0,
	    0,
	    0,
	    0,
	    0,
	    0,
	    128, // 0b10000000,
	    192, // 0b11000000,
	    224, // 0b11100000,
	    240, // 0b11110000,
	    248, // 0b11111000,
	    252, // 0b11111100,
	    254, // 0b11111110,
	    255, // 0b11111111,
	};

public:
public:
	BitReader()
	    : input(nullptr)
	    , index(0) {}
	uint8_t* input;
	uint32_t index;

public:
	void SetStream(uint8_t* input) {
		this->input = input;
		index       = 0;
	}

	inline uint8_t  BitIndex() const { return (index & 7); }