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 bytes2hex(b, sep=''):
  25         if not sep:
  26             return b.hex()
  27         return sep.join(map('{:02x}'.format, b))
  28
  29     def bytes2str(b): return b.decode('latin-1')
  30     def str2bytes(s): return s.encode('latin-1')
  31     def int2byte(i): return bytes((i,))
  32     def byte2int(b): return b
  33
  34     def iterbytes(b):
  35         """Return an iterator over the elements of a bytes object.
  36
  37         For example, for b'abc' yields b'a', b'b' and then b'c'.
  38         """
  39         for i in range(len(b)):
  40             yield b[i:i+1]
  41
  42     ifilter = filter
  43
  44     maxint = sys.maxsize
  45 else:
  46     import cStringIO
  47     StringIO = BytesIO = cStringIO.StringIO
  48
  49     def bytes2hex(b, sep=''):
  50         res = b.encode('hex')
  51         if not sep:
  52             return res
  53         return sep.join(res[i:i+2] for i in range(0, len(res), 2))
  54
  55     def bytes2str(b): return b
  56     def str2bytes(s): return s
  57     int2byte = chr
  58     byte2int = ord
  59     def iterbytes(b):
  60         return iter(b)
  61
  62     from itertools import ifilter
  63
  64     maxint = sys.maxint
  65
  66
  67 def iterkeys(d):
  68     """Return an iterator over the keys of a dictionary."""
  69     return getattr(d, 'keys' if PY3 else 'iterkeys')()
  70
  71 def itervalues(d):
  72     """Return an iterator over the values of a dictionary."""
  73     return getattr(d, 'values' if PY3 else 'itervalues')()
  74
  75 def iteritems(d):
  76     """Return an iterator over the items of a dictionary."""
  77     return getattr(d, 'items' if PY3 else 'iteritems')()
  78
  79 try:
  80     from collections.abc import Mapping  # python >= 3.3
  81 except ImportError:
  82     from collections import Mapping  # python < 3.3