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# -*- encoding: utf-8 -*-
##############################################################################
#
# Copyright (C) 2009 EduSense BV (<http://www.edusense.nl>).
# All Rights Reserved
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
##############################################################################
__all__ = [
'Field', 'Filler', 'DateField', 'NumberField', 'RightAlignedField',
'RecordType', 'Record', 'asciify'
]
__doc__ = '''Ease working with fixed length records in files'''
from datetime import datetime, date
# Correct python2.4 issues
try:
datetime.strptime
def strpdate(str, format):
return datetime.strptime(str, format).date()
except AttributeError:
import time
def strpdate(str, format):
tm = time.strptime(str, format)
return date(tm.tm_year, tm.tm_mon, tm.tm_mday)
import unicodedata
class Field(object):
'''Base Field class - fixed length left aligned string field in a record'''
def __init__(self, name, length=1, fillchar=' ', cast=str):
self.name = name.replace(' ', '_')
self.length = length
self.fillchar = fillchar
self.cast = cast
def format(self, value):
value = self.cast(value)
if len(value) > self.length:
return value[:self.length]
return value.ljust(self.length, self.fillchar)
def take(self, buffer):
offset = hasattr(self, 'offset') and self.offset or 0
return self.cast(buffer[offset:offset + self.length].rstrip(self.fillchar))
def __repr__(self):
return '%s "%s"' % (self.__class__.__name__, self.name)
class Filler(Field):
'''Constant value field'''
def __init__(self, name, length=1, value=' '):
super(Filler, self).__init__(name, length, cast=str)
self.value = str(value)
def take(self, buffer):
return self.format(buffer)
def format(self, value):
return super(Filler, self).format(
self.value * (self.length / len(self.value) +1)
)
class DateField(Field):
'''Variable date field'''
def __init__(self, name, format='%Y-%m-%d', auto=False, cast=str):
length = len(date.today().strftime(format))
super(DateField, self).__init__(name, length, cast=cast)
self.dateformat = format
self.auto = auto
def format(self, value):
if isinstance(value, (str, unicode)) and \
len(value.strip()) == self.length:
value = strpdate(value, self.dateformat)
elif not isinstance(value, (datetime, date)):
value = date.today()
return value.strftime(self.dateformat)
def take(self, buffer):
value = super(DateField, self).take(buffer)
if value:
return strpdate(value, self.dateformat)
return self.auto and date.today() or None
class RightAlignedField(Field):
'''Deviation of Field: right aligned'''
def format(self, value):
if len(value) > self.length:
return value[-self.length:]
return value.rjust(self.length, self.fillchar)
def take(self, buffer):
offset = hasattr(self, 'offset') and self.offset or 0
return self.cast(buffer[offset:offset + self.length].lstrip(self.fillchar))
class NumberField(RightAlignedField):
'''Deviation of Field: left zero filled'''
def __init__(self, *args, **kwargs):
kwargs['fillchar'] = '0'
super(NumberField, self).__init__(*args, **kwargs)
def format(self, value):
return super(NumberField, self).format(self.cast(value or ''))
class RecordType(object):
fields = []
def __init__(self, fields=[]):
if fields:
self.fields = fields
offset = 0
for field in self.fields:
field.offset = offset
offset += field.length
def __len__(self):
return reduce(lambda x,y: x+y.length, self.fields, 0)
def __contains__(self, key):
return any(lambda x, y=key: x.name == y, self.fields)
def __getitem__(self, key):
for field in self.fields:
if field.name == key:
return field
raise KeyError, 'No such field: %s' % key
def format(self, buffer):
result = []
for field in self.fields:
result.append(field.format(field.take(buffer)))
return ''.join(result)
def take(self, buffer):
return dict(zip([x.name for x in self.fields],
[x.take(buffer) for x in self.fields]
))
class Record(object):
_recordtype = None
def __init__(self, recordtype=None, value=''):
if hasattr(self, '_fields') and self._fields:
self._recordtype = RecordType(self._fields)
if not self._recordtype and not recordtype:
raise ValueError, 'No recordtype specified'
if not self._recordtype:
self._recordtype = recordtype()
self._length = len(self._recordtype)
self._value = value.ljust(self._length)[:self._length]
def __len__(self):
return self._length
def __setattr__(self, attr, value):
if attr.startswith('_'):
super(Record, self).__setattr__(attr, value)
else:
field = self._recordtype[attr]
self._value = self._value[:field.offset] + \
field.format(value) + \
self._value[field.offset + field.length:]
def __getattr__(self, attr):
if attr.startswith('_'):
return super(Record, self).__getattr__(attr)
field = self._recordtype[attr]
return field.take(self._value)
def __str__(self):
return self._recordtype.format(self._value)
def __unicode__(self):
return unicode(self.cast(self))
def asciify(str):
return unicodedata.normalize('NFKD', str).encode('ascii', 'ignore')
# vim:expandtab:smartindent:tabstop=4:softtabstop=4:shiftwidth=4:
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