elftools/common/py3compat.py

   1 #-------------------------------------------------------------------------------
   2 # elftools: common/py3compat.py
   3 #
   4 # Python 2/3 compatibility code
   5 #
   6 # Eli Bendersky (eliben@gmail.com)
   7 # This code is in the public domain
   8 #-------------------------------------------------------------------------------
   9 import sys
  10 PY3 = sys.version_info[0] == 3
  11
  12
  13 if PY3:
  14     import io
  15     StringIO = io.StringIO
  16     BytesIO = io.BytesIO
  17
  18     # Functions for acting on bytestrings and strings. In Python 2 and 3,
  19     # strings and bytes are the same and chr/ord can be used to convert between
  20     # numeric byte values and their string pepresentations. In Python 3, bytes
  21     # and strings are different types and bytes hold numeric values when
  22     # iterated over.
  23
  24     def bytes2str(b): return b.decode('latin-1')
  25     def str2bytes(s): return s.encode('latin-1')
  26     def int2byte(i): return bytes((i,))
  27     def byte2int(b): return b
  28
  29     def iterbytes(b):
  30         """Return an iterator over the elements of a bytes object.
  31
  32         For example, for b'abc' yields b'a', b'b' and then b'c'.
  33         """
  34         for i in range(len(b)):
  35             yield b[i:i+1]
  36
  37     ifilter = filter
  38
  39     maxint = sys.maxsize
  40 else:
  41     import cStringIO
  42     StringIO = BytesIO = cStringIO.StringIO
  43
  44     def bytes2str(b): return b
  45     def str2bytes(s): return s
  46     int2byte = chr
  47     byte2int = ord
  48     def iterbytes(b):
  49         return iter(b)
  50
  51     from itertools import ifilter
  52
  53     maxint = sys.maxint
  54
  55
  56 def iterkeys(d):
  57     """Return an iterator over the keys of a dictionary."""
  58     return getattr(d, 'keys' if PY3 else 'iterkeys')()
  59
  60 def itervalues(d):
  61     """Return an iterator over the values of a dictionary."""
  62     return getattr(d, 'values' if PY3 else 'itervalues')()
  63
  64 def iteritems(d):
  65     """Return an iterator over the items of a dictionary."""
  66     return getattr(d, 'items' if PY3 else 'iteritems')()
  67
  68 try:
  69     from collections.abc import Mapping  # python >= 3.3
  70 except ImportError:
  71     from collections import Mapping  # python < 3.3