Talker Alias 7bit vs 8bit encoding/decoding

test.go

package main

import "fmt"

func main() {
	data := []byte{
		0x01,
		0xFF,
		0xFF,
		0xFF,
		0xFF,
		0xFF,
		0xFF,
	}
	out := make([]byte, 7)

	for i := 7; i < 56; i++ {
		fmt.Printf("%d, %d -> %d %d\n", i/8, (7 - (i % 8)), (i-7)/7, 6-(i%7))
		movebit(data, i/8, (7 - (i % 8)), out, (i-7)/7, 6-(i%7))
	}

	fmt.Printf("%v\n", out)

	out2 := make([]byte, 6)
	var bit49 byte
	fmt.Println("Now reverse the function")
	for i := 7; i < 56; i++ {
		if i > 7 {
			fmt.Printf("%d, %d -> %d %d\n", (i-7)/7, 6-(i%7), (i/8)-1, (7 - (i % 8)))
			movebit(out, (i-7)/7, 6-(i%7), out2, (i/8)-1, (7 - (i % 8)))
		} else {
			bit49 = (out[0] & 0x40) >> 6
		}
	}

	fmt.Printf("%v %v\n", out2, bit49)

}

func movebit(src []byte, srcByte int, srcBit int, dst []byte, dstByte int, dstBit int) {
	bit := (src[srcByte] >> uint8(srcBit)) & 1
	if bit >= 1 {
		dst[dstByte] |= 1 << uint8(dstBit)
	} else {
		dst[dstByte] &= 0 << uint8(dstBit)
	}
}