go-redis bitmap demo

go-redis-bitmap.go

func appendBytes(bs []byte, b byte) []byte {
	var a byte
	for i := 0; i < 8; i++ {
		a = b
		b <<= 1
		b >>= 1
		switch a {
		case b:
			bs = append(bs, '0')
		default:
			bs = append(bs, '1')
		}
		b <<= 1
	}
	return bs
}

// BitmapBytesToBytes bitmap 转 bytes
func BitmapBytesToBytes(bs []byte) []byte {
	l := len(bs)
	bl := l*8 + l + 1
	buf := make([]byte, 0, bl)
	for _, b := range bs {
		buf = appendBytes(buf, b)
	}
	return buf
}

func TestBitmap(t *testing.T) {

	ctx := context.Background()
	RedisClient := redis.NewClient(&redis.Options{
		Addr:     "10.10.8.143:6379",
		Password: "aGGewe8wmJ",
		DB:       1,
	})
	RedisClient.SetBit(ctx, "key_bitmap", 0, 0)
	RedisClient.SetBit(ctx, "key_bitmap", 1, 1)
	RedisClient.SetBit(ctx, "key_bitmap", 2, 0)
	RedisClient.SetBit(ctx, "key_bitmap", 3, 0)
	RedisClient.SetBit(ctx, "key_bitmap", 4, 1)
	RedisClient.SetBit(ctx, "key_bitmap", 5, 1)
	RedisClient.SetBit(ctx, "key_bitmap", 6, 0)
	res, _ := RedisClient.Get(ctx, "key_bitmap").Bytes()
	
	// way1
	b := BitmapBytesToBytes(res)
	fmt.Printf("%s\n", b) //01001100

	// way2
	var bits string
	for _, v := range res {
		bits = fmt.Sprintf("%s%0.8b", bits, v)
	}
	fmt.Printf("%s\n", bits) // 01001100

	r, _ := RedisClient.BitCount(ctx, "key_bitmap", &redis.BitCount{
		Start: 0, // PS: byte index, not bit index
		End:   1,
	}).Result()
	fmt.Println(r) // 3
}