newint.py 文件源码

def to_bytes(self, length, byteorder='big', signed=False):
        """
        Return an array of bytes representing an integer.

        The integer is represented using length bytes.  An OverflowError is
        raised if the integer is not representable with the given number of
        bytes.

        The byteorder argument determines the byte order used to represent the
        integer.  If byteorder is 'big', the most significant byte is at the
        beginning of the byte array.  If byteorder is 'little', the most
        significant byte is at the end of the byte array.  To request the native
        byte order of the host system, use `sys.byteorder' as the byte order value.

        The signed keyword-only argument determines whether two's complement is
        used to represent the integer.  If signed is False and a negative integer
        is given, an OverflowError is raised.
        """
        if length < 0:
            raise ValueError("length argument must be non-negative")
        if length == 0 and self == 0:
            return newbytes()
        if signed and self < 0:
            bits = length * 8
            num = (2**bits) + self
            if num <= 0:
                raise OverflowError("int too smal to convert")
        else:
            if self < 0:
                raise OverflowError("can't convert negative int to unsigned")
            num = self
        if byteorder not in ('little', 'big'):
            raise ValueError("byteorder must be either 'little' or 'big'")
        h = b'%x' % num
        s = newbytes((b'0'*(len(h) % 2) + h).zfill(length*2).decode('hex'))
        if signed:
            high_set = s[0] & 0x80
            if self > 0 and high_set:
                raise OverflowError("int too big to convert")
            if self < 0 and not high_set:
                raise OverflowError("int too small to convert")
        if len(s) > length:
            raise OverflowError("int too big to convert")
        return s if byteorder == 'big' else s[::-1]