depends.py 文件源码

def _iter_code(code):
    """Yield '(op,arg)' pair for each operation in code object 'code'"""

    from array import array
    from dis import HAVE_ARGUMENT, EXTENDED_ARG

    bytes = array('b', code.co_code)
    eof = len(code.co_code)

    ptr = 0
    extended_arg = 0

    while ptr < eof:

        op = bytes[ptr]

        if op >= HAVE_ARGUMENT:

            arg = bytes[ptr + 1] + bytes[ptr + 2] * 256 + extended_arg
            ptr += 3

            if op == EXTENDED_ARG:
                long_type = six.integer_types[-1]
                extended_arg = arg * long_type(65536)
                continue

        else:
            arg = None
            ptr += 1

        yield op, arg