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