package utils

// IsBigEnd 判断是否大端
func IsBigEnd() bool {
	var (
		v3 uint32
		b3 [4]byte
	)
	v3 = 257
	b3[0] = uint8(v3)
	b3[1] = uint8(v3 >> 8)
	b3[2] = uint8(v3 >> 16)
	b3[3] = uint8(v3 >> 24)
	if b3[0] == 1 {
		return false
	}
	return true
}

func IntoByte(c int) byte {
	var (
		b3 [4]byte
	)
	b3[0] = uint8(c)
	b3[1] = uint8(c >> 8)
	b3[2] = uint8(c >> 16)
	b3[3] = uint8(c >> 24)
	if IsBigEnd() {
		return b3[3]
	}
	return b3[0]
}

// HfWord2byte 将一个int16转换为两个byte
func HfWord2byte(obj int) (slice []byte) {
	slice = append(slice, IntoByte(obj>>8))
	slice = append(slice, IntoByte(obj&0xFF))
	return
}

// Word2byte 将一个int转换为四个byte
func Word2byte(obj int) (slice []byte) {
	slice = append(slice, IntoByte(obj>>24))
	slice = append(slice, IntoByte(obj>>16))
	slice = append(slice, IntoByte(obj>>8))
	slice = append(slice, IntoByte(obj&0xFF))
	return
}

func CalCRC16HJ212(data []byte) uint16 {
	var (
		crc  uint16 = 0xFFFF
		iNum uint16 = 0
	)
	length := len(data)
	for i := 0; i < length; i++ {
		iNum = uint16(data[i])
		crc = (crc >> 8) & 0x00FF
		crc = crc ^ iNum
		for j := 0; j < 8; j++ {
			flag := crc % 2
			crc = crc >> 1
			if flag == 1 {
				crc = crc ^ 0xA001
			}
		}
	}
	return crc
}