old_contents: # Python Security Project (PySec) and its related class files.
  #
  # PySec is a set of tools for secure application development under Linux
  #
  # Copyright 2014 PySec development team
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #   http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  #
  # -*- coding: ascii -*-
  """Various utilities for strings manipulation."""
  from pysec import lang
  from pysec.utils import xrange, eq
  from pysec.xsplit import xbounds
  
  
  def erepr(s):
      """Return a escaped string, like repr, without quotes"""
      return str(s).encode('string_escape')
  
  
  def single_byte_xor(s, xor):
      xor = int(xor)
      if xor < 0 or xor > 255:
          raise ValueError(lang.STR_WRONG_BYTE)
      return ''.join(chr(ord(ch) ^ xor) for ch in str(s))
  
  
  def common_iprefix(*strings):
      """Return the length of the common prefix of strings"""
      i = 0
      for i in xrange(0, min(len(s) for s in strings)):
          if not eq(*(s[i] for s in strings)):
              return i
      return i
  
  
  def common_prefix(*strings):
      """Return the common prefix of strings"""
      return '' if not strings else strings[0][:common_iprefix(*strings)]
  
  
  def common_isuffix(*strings):
      """Return the length of the common suffix of strings"""
      i = -1
      for i in xrange(0, min(len(s) for s in strings)):
          if not eq(*(s[len(s) - i - 1] for s in strings)):
              return i
      return i + 1
  
  
  def common_suffix(*strings):
      """Return the common prefix of strings"""
      return strings[0][len(strings[0]) - common_isuffix(*strings):] \
             if strings else ''
  
  
  def split_newlines(string):
      """Generator of lines in *string* ending with '\r\n', '\n', '\n'"""
      newline_chars = 0
      line_start = 0
      for i in xrange(0, len(string)):
          if string[i] in ('\r', '\n'):
              if not newline_chars:
                  yield string[line_start:i]
                  newline_chars = 1
          else:
              if newline_chars:
                  line_start = i
                  newline_chars = 0
      if not newline_chars:
          yield string[line_start:]
  
  
new_contents: # Python Security Project (PySec) and its related class files.
  #
  # PySec is a set of tools for secure application development under Linux
  #
  # Copyright 2014 PySec development team
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #   http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  #
  # -*- coding: ascii -*-
  """Various utilities for strings manipulation."""
  from pysec import lang
  from pysec.utils import xrange, eq
  from pysec.xsplit import xbounds
  
  
  def erepr(s):
      """Return a escaped string, like repr, without quotes"""
      return str(s).encode('string_escape')
  
  
  def single_byte_xor(s, xor):
      xor = int(xor)
      if xor < 0 or xor > 255:
          raise ValueError(lang.STR_WRONG_BYTE)
      return ''.join(chr(ord(ch) ^ xor) for ch in str(s))
  
  
  def common_iprefix(*strings):
      """Return the length of the common prefix of strings"""
      i = 0
      for i in xrange(0, min(len(s) for s in strings)):
          if not eq(*(s[i] for s in strings)):
              return i
      return i
  
  
  def common_prefix(*strings):
      """Return the common prefix of strings"""
      return '' if not strings else strings[0][:common_iprefix(*strings)]
  
  
  def common_isuffix(*strings):
      """Return the length of the common suffix of strings"""
      i = -1
      for i in xrange(0, min(len(s) for s in strings)):
          if not eq(*(s[len(s) - i - 1] for s in strings)):
              return i
      return i + 1
  
  
  def common_suffix(*strings):
      """Return the common prefix of strings"""
      return strings[0][len(strings[0]) - common_isuffix(*strings):] \
             if strings else ''
  
  
  def split_newlines(string):
      """Generator of lines in *string* ending with '\r\n', '\n', '\n'"""
      newline_chars = 0
      line_start = 0
      for i in xrange(0, len(string)):
          if string[i] in ('\r', '\n'):
              if not newline_chars:
                  yield string[line_start:i]
                  newline_chars = 1
          else:
              if newline_chars:
                  line_start = i
                  newline_chars = 0
      if not newline_chars:
          yield string[line_start:]
  
  
  def only_printable(string):
      """Remove all not printable characters from *string*"""
      return ''.join(ch for ch in string if 32 <= ord(ch) <= 126)
  
  
  def only_visible(string):
      """Remove all not visible characters from *string*"""
      return ''.join(ch for ch in string if 33 <= ord(ch) <= 126)
  
subject: add functions to remove not-printable and not-visible chars