# Copyright (c) 2011, Bernhard Leiner
# Copyright (c) 2013-2018 Alexander Belchenko
# All rights reserved.
#
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# with or without modification, are permitted provided
# that the following conditions are met:
#
# * Redistributions of source code must retain
#   the above copyright notice, this list of conditions
#   and the following disclaimer.
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#   the above copyright notice, this list of conditions
#   and the following disclaimer in the documentation
#   and/or other materials provided with the distribution.
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'''Compatibility functions for python 2 and 3.

@author     Bernhard Leiner (bleiner AT gmail com)
@author     Alexander Belchenko (alexander belchenko AT gmail com)
'''

__docformat__ = "javadoc"


import sys, array


if sys.version_info[0] >= 3:
    # Python 3
    Python = 3

    def asbytes(s):
        if isinstance(s, bytes):
            return s
        return s.encode('latin1')
    def asstr(s):
        if isinstance(s, str):
            return s
        return s.decode('latin1')

    array_tobytes = getattr(array.array, "tobytes", array.array.tostring)

    IntTypes = (int,)
    StrType = str
    UnicodeType = str

    range_g = range     # range generator
    def range_l(*args): # range list
        return list(range(*args))

    def dict_keys(dikt):        # dict keys list
        return list(dikt.keys())
    def dict_keys_g(dikt):      # dict keys generator
        return dikt.keys()
    def dict_items_g(dikt):     # dict items generator
        return dikt.items()

    from io import StringIO, BytesIO

    def get_binary_stdout():
        return sys.stdout.buffer

    def get_binary_stdin():
        return sys.stdin.buffer

else:
    # Python 2
    Python = 2

    asbytes = str
    asstr = str

    array_tobytes = array.array.tostring

    IntTypes = (int, long)
    StrType = basestring
    UnicodeType = unicode

    #range_g = xrange    # range generator
    def range_g(*args):
        # we want to use xrange here but on python 2 it does not work with long ints
        try:
            return xrange(*args)
        except OverflowError:
            start = 0
            stop = 0
            step = 1
            n = len(args)
            if n == 1:
                stop = args[0]
            elif n == 2:
                start, stop = args
            elif n == 3:
                start, stop, step = args
            else:
                raise TypeError('wrong number of arguments in range_g call!')
            if step == 0:
                raise ValueError('step cannot be zero')
            if step > 0:
                def up(start, stop, step):
                    while start < stop:
                        yield start
                        start += step
                return up(start, stop, step)
            else:
                def down(start, stop, step):
                    while start > stop:
                        yield start
                        start += step
                return down(start, stop, step)

    range_l = range     # range list

    def dict_keys(dikt):        # dict keys list
        return dikt.keys()
    def dict_keys_g(dikt):      # dict keys generator
        return dikt.keys()
    def dict_items_g(dikt):     # dict items generator
        return dikt.items()

    from cStringIO import StringIO
    BytesIO = StringIO

    import os
    def _force_stream_binary(stream):
        """Force binary mode for stream on Windows."""
        if os.name == 'nt':
            f_fileno = getattr(stream, 'fileno', None)
            if f_fileno:
                fileno = f_fileno()
                if fileno >= 0:
                    import msvcrt
                    msvcrt.setmode(fileno, os.O_BINARY)
        return stream

    def get_binary_stdout():
        return _force_stream_binary(sys.stdout)

    def get_binary_stdin():
        return _force_stream_binary(sys.stdin)
