bit.go

package main

import "io"

func setEffect(player *playerData, flag EFF) {
	player.effects = (player.effects | flag)
}

func removeEffect(player *playerData, flag EFF) {
	player.effects = (player.effects &^ flag)
}

func hasEffects(player *playerData, flag EFF) bool {
	return player.effects&flag == flag
}

func hasAnyEffects(player *playerData, flag EFF) bool {
	return player.effects&flag != 0
}

type BitReader struct {
	reader io.ByteReader
	byte   byte
	offset byte
}

func New(r io.ByteReader) *BitReader {
	return &BitReader{r, 0, 0}
}

func (r *BitReader) ReadBit() (bool, error) {
	if r.offset == 8 {
		r.offset = 0
	}
	if r.offset == 0 {
		var err error
		if r.byte, err = r.reader.ReadByte(); err != nil {
			return false, err
		}
	}
	bit := (r.byte & (0x80 >> r.offset)) != 0
	r.offset++
	return bit, nil
}

func (r *BitReader) ReadInt(nbits int) (int, error) {
	var result int
	for i := nbits - 1; i >= 0; i-- {
		bit, err := r.ReadBit()
		if err != nil {
			return 0, err
		}
		if bit {
			result |= 1 << uint(i)
		}
	}
	tmp := int(result)
	return tmp, nil
}

func (r *BitReader) ReadBits(nbits int) (byte, error) {
	var result int
	for i := nbits - 1; i >= 0; i-- {
		bit, err := r.ReadBit()
		if err != nil {
			return 0, err
		}
		if bit {
			result |= 1 << uint(i)
		}
	}
	tmp := byte(result)
	return tmp, nil
}