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 assert PY3, '''\
  12 Python 2 is no longer supported by pyelftools; if you need to use Python 2,
  13 please download an older pyelftools version (such as version 0.29).
  14 '''
  15
  16
  17 if PY3:
  18     import io
  19     from pathlib import Path
  20
  21     StringIO = io.StringIO
  22     BytesIO = io.BytesIO
  23
  24     # Functions for acting on bytestrings and strings. In Python 2 and 3,
  25     # strings and bytes are the same and chr/ord can be used to convert between
  26     # numeric byte values and their string representations. In Python 3, bytes
  27     # and strings are different types and bytes hold numeric values when
  28     # iterated over.
  29
  30     def bytes2hex(b, sep=''):
  31         if not sep:
  32             return b.hex()
  33         return sep.join(map('{:02x}'.format, b))
  34
  35     def bytes2str(b): return b.decode('latin-1')
  36     def str2bytes(s): return s.encode('latin-1')
  37     def int2byte(i): return bytes((i,))
  38     def byte2int(b): return b
  39
  40     def iterbytes(b):
  41         """Return an iterator over the elements of a bytes object.
  42
  43         For example, for b'abc' yields b'a', b'b' and then b'c'.
  44         """
  45         for i in range(len(b)):
  46             yield b[i:i+1]
  47
  48     ifilter = filter
  49
  50     maxint = sys.maxsize
  51
  52     def path_to_posix(s):
  53         return Path(s).as_posix()
  54
  55 else:
  56     import cStringIO
  57     import os
  58     import posixpath
  59
  60     StringIO = BytesIO = cStringIO.StringIO
  61
  62     def bytes2hex(b, sep=''):
  63         res = b.encode('hex')
  64         if not sep:
  65             return res
  66         return sep.join(res[i:i+2] for i in range(0, len(res), 2))
  67
  68     def bytes2str(b): return b
  69     def str2bytes(s): return s
  70     int2byte = chr
  71     byte2int = ord
  72     def iterbytes(b):
  73         return iter(b)
  74
  75     from itertools import ifilter
  76
  77     maxint = sys.maxint
  78
  79     def path_to_posix(s):
  80         return posixpath.join(*os.path.split(s))
  81
  82
  83 def iterkeys(d):
  84     """Return an iterator over the keys of a dictionary."""
  85     return getattr(d, 'keys' if PY3 else 'iterkeys')()
  86
  87 def itervalues(d):
  88     """Return an iterator over the values of a dictionary."""
  89     return getattr(d, 'values' if PY3 else 'itervalues')()
  90
  91 def iteritems(d):
  92     """Return an iterator over the items of a dictionary."""
  93     return getattr(d, 'items' if PY3 else 'iteritems')()
  94
  95 try:
  96     from collections.abc import Mapping  # python >= 3.3
  97 except ImportError:
  98     from collections import Mapping  # python < 3.3