text: # sqlalchemy/processors.py
  # Copyright (C) 2010-2014 the SQLAlchemy authors and contributors <see AUTHORS file>
  # Copyright (C) 2010 Gaetan de Menten gdementen@gmail.com
  #
  # This module is part of SQLAlchemy and is released under
  # the MIT License: http://www.opensource.org/licenses/mit-license.php
  
  """defines generic type conversion functions, as used in bind and result
  processors.
  
  They all share one common characteristic: None is passed through unchanged.
  
  """
  
  import codecs
  import re
  import datetime
  from . import util
  
  
  def str_to_datetime_processor_factory(regexp, type_):
      rmatch = regexp.match
      # Even on python2.6 datetime.strptime is both slower than this code
      # and it does not support microseconds.
      has_named_groups = bool(regexp.groupindex)
  
      def process(value):
          if value is None:
              return None
          else:
              try:
                  m = rmatch(value)
              except TypeError:
                  raise ValueError("Couldn't parse %s string '%r' "
                                  "- value is not a string." %
                                  (type_.__name__, value))
              if m is None:
                  raise ValueError("Couldn't parse %s string: "
                                  "'%s'" % (type_.__name__, value))
              if has_named_groups:
                  groups = m.groupdict(0)
                  return type_(**dict(list(zip(iter(groups.keys()),
                                          list(map(int, iter(groups.values())))))))
              else:
                  return type_(*list(map(int, m.groups(0))))
      return process
  
  
  def boolean_to_int(value):
      if value is None:
          return None
      else:
          return int(value)
  
  
  def py_fallback():
      def to_unicode_processor_factory(encoding, errors=None):
          decoder = codecs.getdecoder(encoding)
  
          def process(value):
              if value is None:
                  return None
              else:
                  # decoder returns a tuple: (value, len). Simply dropping the
                  # len part is safe: it is done that way in the normal
                  # 'xx'.decode(encoding) code path.
                  return decoder(value, errors)[0]
          return process
  
      def to_conditional_unicode_processor_factory(encoding, errors=None):
          decoder = codecs.getdecoder(encoding)
  
          def process(value):
              if value is None:
                  return None
              elif isinstance(value, util.text_type):
                  return value
              else:
                  # decoder returns a tuple: (value, len). Simply dropping the
                  # len part is safe: it is done that way in the normal
                  # 'xx'.decode(encoding) code path.
                  return decoder(value, errors)[0]
          return process
  
      def to_decimal_processor_factory(target_class, scale):
          fstring = "%%.%df" % scale
  
          def process(value):
              if value is None:
                  return None
              else:
                  return target_class(fstring % value)
          return process
  
      def to_float(value):
          if value is None:
              return None
          else:
              return float(value)
  
      def to_str(value):
          if value is None:
              return None
          else:
              return str(value)
  
      def int_to_boolean(value):
          if value is None:
              return None
          else:
              return value and True or False
  
      DATETIME_RE = re.compile(
                          "(\d+)-(\d+)-(\d+) (\d+):(\d+):(\d+)(?:\.(\d+))?")
      TIME_RE = re.compile("(\d+):(\d+):(\d+)(?:\.(\d+))?")
      DATE_RE = re.compile("(\d+)-(\d+)-(\d+)")
  
      str_to_datetime = str_to_datetime_processor_factory(DATETIME_RE,
                                                          datetime.datetime)
      str_to_time = str_to_datetime_processor_factory(TIME_RE, datetime.time)
      str_to_date = str_to_datetime_processor_factory(DATE_RE, datetime.date)
      return locals()
  
  try:
      from sqlalchemy.cprocessors import UnicodeResultProcessor, \
                                         DecimalResultProcessor, \
                                         to_float, to_str, int_to_boolean, \
                                         str_to_datetime, str_to_time, \
                                         str_to_date
  
      def to_unicode_processor_factory(encoding, errors=None):
          if errors is not None:
              return UnicodeResultProcessor(encoding, errors).process
          else:
              return UnicodeResultProcessor(encoding).process
  
      def to_conditional_unicode_processor_factory(encoding, errors=None):
          if errors is not None:
              return UnicodeResultProcessor(encoding, errors).conditional_process
          else:
              return UnicodeResultProcessor(encoding).conditional_process
  
      def to_decimal_processor_factory(target_class, scale):
          # Note that the scale argument is not taken into account for integer
          # values in the C implementation while it is in the Python one.
          # For example, the Python implementation might return
          # Decimal('5.00000') whereas the C implementation will
          # return Decimal('5'). These are equivalent of course.
          return DecimalResultProcessor(target_class, "%%.%df" % scale).process
  
  except ImportError:
      globals().update(py_fallback())
  