slixmpp/util/misc_ops.py

   1 import sys
   2 import hashlib
   3
   4
   5 def unicode(text):
   6     if sys.version_info < (3, 0):
   7         if isinstance(text, str):
   8             text = text.decode('utf-8')
   9         import __builtin__
  10         return __builtin__.unicode(text)
  11     elif not isinstance(text, str):
  12         return text.decode('utf-8')
  13     else:
  14         return text
  15
  16
  17 def bytes(text):
  18     """
  19     Convert Unicode text to UTF-8 encoded bytes.
  20
  21     Since Python 2.6+ and Python 3+ have similar but incompatible
  22     signatures, this function unifies the two to keep code sane.
  23
  24     :param text: Unicode text to convert to bytes
  25     :rtype: bytes (Python3), str (Python2.6+)
  26     """
  27     if text is None:
  28         return b''
  29
  30     if sys.version_info < (3, 0):
  31         import __builtin__
  32         return __builtin__.bytes(text)
  33     else:
  34         import builtins
  35         if isinstance(text, builtins.bytes):
  36             # We already have bytes, so do nothing
  37             return text
  38         if isinstance(text, list):
  39             # Convert a list of integers to bytes
  40             return builtins.bytes(text)
  41         else:
  42             # Convert UTF-8 text to bytes
  43             return builtins.bytes(text, encoding='utf-8')
  44
  45
  46 def quote(text):
  47     """
  48     Enclose in quotes and escape internal slashes and double quotes.
  49
  50     :param text: A Unicode or byte string.
  51     """
  52     text = bytes(text)
  53     return b'"' + text.replace(b'\\', b'\\\\').replace(b'"', b'\\"') + b'"'
  54
  55
  56 def num_to_bytes(num):
  57     """
  58     Convert an integer into a four byte sequence.
  59
  60     :param integer num: An integer to convert to its byte representation.
  61     """
  62     bval = b''
  63     bval += bytes(chr(0xFF & (num >> 24)))
  64     bval += bytes(chr(0xFF & (num >> 16)))
  65     bval += bytes(chr(0xFF & (num >> 8)))
  66     bval += bytes(chr(0xFF & (num >> 0)))
  67     return bval
  68
  69
  70 def bytes_to_num(bval):
  71     """
  72     Convert a four byte sequence to an integer.
  73
  74     :param bytes bval: A four byte sequence to turn into an integer.
  75     """
  76     num = 0
  77     num += ord(bval[0] << 24)
  78     num += ord(bval[1] << 16)
  79     num += ord(bval[2] << 8)
  80     num += ord(bval[3])
  81     return num
  82
  83
  84 def XOR(x, y):
  85     """
  86     Return the results of an XOR operation on two equal length byte strings.
  87
  88     :param bytes x: A byte string
  89     :param bytes y: A byte string
  90     :rtype: bytes
  91     """
  92     result = b''
  93     for a, b in zip(x, y):
  94         if sys.version_info < (3, 0):
  95             result += chr((ord(a) ^ ord(b)))
  96         else:
  97             result += bytes([a ^ b])
  98     return result
  99
 100
 101 def hash(name):
 102     """
 103     Return a hash function implementing the given algorithm.
 104
 105     :param name: The name of the hashing algorithm to use.
 106     :type name: string
 107
 108     :rtype: function
 109     """
 110     name = name.lower()
 111     if name.startswith('sha-'):
 112         name = 'sha' + name[4:]
 113     if name in dir(hashlib):
 114         return getattr(hashlib, name)
 115     return None
 116
 117
 118 def hashes():
 119     """
 120     Return a list of available hashing algorithms.
 121
 122     :rtype: list of strings
 123     """
 124     t = []
 125     if 'md5' in dir(hashlib):
 126         t = ['MD5']
 127     if 'md2' in dir(hashlib):
 128         t += ['MD2']
 129     hashes = ['SHA-' + h[3:] for h in dir(hashlib) if h.startswith('sha')]
 130     return t + hashes
 131
 132
 133 def setdefaultencoding(encoding):
 134     """
 135     Set the current default string encoding used by the Unicode implementation.
 136
 137     Actually calls sys.setdefaultencoding under the hood - see the docs for that
 138     for more details.  This method exists only as a way to call find/call it
 139     even after it has been 'deleted' when the site module is executed.
 140
 141     :param string encoding: An encoding name, compatible with sys.setdefaultencoding
 142     """
 143     func = getattr(sys, 'setdefaultencoding', None)
 144     if func is None:
 145         import gc
 146         import types
 147         for obj in gc.get_objects():
 148             if (isinstance(obj, types.BuiltinFunctionType)
 149                     and obj.__name__ == 'setdefaultencoding'):
 150                 func = obj
 151                 break
 152         if func is None:
 153             raise RuntimeError("Could not find setdefaultencoding")
 154         sys.setdefaultencoding = func
 155     return func(encoding)
 156
 157
 158 def safedict(data):
 159     if sys.version_info < (2, 7):
 160         safe = {}
 161         for key in data:
 162             safe[key.encode('utf8')] = data[key]
 163         return safe
 164     else:
 165         return data