1 #!/usr/bin/env python 2 3 """ 4 Reader and accessor classes for indexing. 5 6 Copyright (C) 2011 Paul Boddie <paul@boddie.org.uk> 7 8 This program is free software; you can redistribute it and/or modify it under 9 the terms of the GNU General Public License as published by the Free Software 10 Foundation; either version 3 of the License, or (at your option) any later 11 version. 12 13 This program is distributed in the hope that it will be useful, but WITHOUT ANY 14 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A 15 PARTICULAR PURPOSE. See the GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License along 18 with this program. If not, see <http://www.gnu.org/licenses/>. 19 """ 20 21 class TextFile: 22 23 "A wrapper around text files." 24 25 def __init__(self, f): 26 self.f = f 27 28 def seek(self, pos): 29 self.f.seek(pos) 30 31 def get_records(self): 32 return self.f.xreadlines() 33 34 class DelimitedRecord: 35 36 "An accessor using a delimiter to split a record." 37 38 def __init__(self, keys=None, delimiter=None): 39 40 """ 41 Initialise the accessor using a sequence of 'keys' indicating the 42 columns in each record that provide the values in the eventual compound 43 key provided by each record, along with a 'delimiter' indicating how 44 such columns are identified. 45 """ 46 47 self.keys = keys or [0] 48 self.delimiter = delimiter 49 50 def get_key(self, record): 51 values = record.split(self.delimiter) 52 return [values[key] for key in self.keys] 53 54 # vim: tabstop=4 expandtab shiftwidth=4