package goutils

func MergeSliceByte(ss ...[]byte) []byte {
	switch len(ss) {
	case 0:
		return nil
	case 1:
		return ss[0]
	default:
		return mergeSliceCopy(ss...)
	}
}

// copy 效率要比 append 大概高20%-30%
func mergeSliceCopy(ss ...[]byte) []byte {
	length := 0
	for _, s := range ss {
		length += len(s)
	}

	slice := make([]byte, length)
	index := 0
	for _, s := range ss {
		copy(slice[index:], s)
		index += len(s)
	}
	return slice
}

func mergeSliceAppend(ss ...[]byte) []byte {
	slice := make([]byte, 0)
	for _, s := range ss {
		slice = append(slice, s...)
	}
	return slice
}

func ReverseByte(arr []byte) []byte {
	length := len(arr)
	for i := 0; i < length/2; i++ {
		idx := length - 1 - i
		temp := arr[i]
		arr[i] = arr[idx]
		arr[idx] = temp
	}
	return arr
}