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     from pathlib import Path
  16     StringIO = io.StringIO
  17     BytesIO = io.BytesIO
  18
  19     # Functions for acting on bytestrings and strings. In Python 2 and 3,
  20     # strings and bytes are the same and chr/ord can be used to convert between
  21     # numeric byte values and their string pepresentations. In Python 3, bytes
  22     # and strings are different types and bytes hold numeric values when
  23     # iterated over.
  24
  25     def bytes2hex(b, sep=''):
  26         if not sep:
  27             return b.hex()
  28         return sep.join(map('{:02x}'.format, b))
  29
  30     def bytes2str(b): return b.decode('latin-1')
  31     def str2bytes(s): return s.encode('latin-1')
  32     def int2byte(i): return bytes((i,))
  33     def byte2int(b): return b
  34
  35     def iterbytes(b):
  36         """Return an iterator over the elements of a bytes object.
  37
  38         For example, for b'abc' yields b'a', b'b' and then b'c'.
  39         """
  40         for i in range(len(b)):
  41             yield b[i:i+1]
  42
  43     ifilter = filter
  44
  45     maxint = sys.maxsize
  46
  47     def path_to_posix(s):
  48         return Path(s).as_posix()
  49
  50 else:
  51     import cStringIO
  52     import os
  53     import posixpath
  54
  55     StringIO = BytesIO = cStringIO.StringIO
  56
  57     def bytes2hex(b, sep=''):
  58         res = b.encode('hex')
  59         if not sep:
  60             return res
  61         return sep.join(res[i:i+2] for i in range(0, len(res), 2))
  62
  63     def bytes2str(b): return b
  64     def str2bytes(s): return s
  65     int2byte = chr
  66     byte2int = ord
  67     def iterbytes(b):
  68         return iter(b)
  69
  70     from itertools import ifilter
  71
  72     maxint = sys.maxint
  73
  74     def path_to_posix(s):
  75         return posixpath.join(*os.path.split(s))
  76
  77
  78 def iterkeys(d):
  79     """Return an iterator over the keys of a dictionary."""
  80     return getattr(d, 'keys' if PY3 else 'iterkeys')()
  81
  82 def itervalues(d):
  83     """Return an iterator over the values of a dictionary."""
  84     return getattr(d, 'values' if PY3 else 'itervalues')()
  85
  86 def iteritems(d):
  87     """Return an iterator over the items of a dictionary."""
  88     return getattr(d, 'items' if PY3 else 'iteritems')()
  89
  90 try:
  91     from collections.abc import Mapping  # python >= 3.3
  92 except ImportError:
  93     from collections import Mapping  # python < 3.3