src/math/sort.h

   1 /* PSPP - a program for statistical analysis.
   2    Copyright (C) 1997-9, 2000, 2006, 2009 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
  16
  17 #ifndef MATH_SORT_H
  18 #define MATH_SORT_H 1
  19
  20 /* Support for sorting cases.
  21
  22    Use sort_create_writer() to sort cases in the most general way:
  23
  24    - Create a casewriter with sort_create_writer(), specifying the sort
  25      criteria.
  26    - Write all of the cases to be sorted to the casewriter, e.g. with
  27      casewriter_write().
  28    - Obtain the sorted results with casewriter_make_reader().
  29
  30   sort_execute() and sort_execute_1var() are shortcuts for situations where the
  31   cases are already available from a casereader.
  32
  33   All of these functions can efficiently sort data bigger than memory. */
  34
  35 struct subcase;
  36 struct caseproto;
  37 struct variable;
  38
  39 extern int min_buffers ;
  40 extern int max_buffers ;
  41
  42 struct casewriter *sort_create_writer (const struct subcase *,
  43                                        const struct caseproto *);
  44 struct casereader *sort_execute (struct casereader *, const struct subcase *);
  45 struct casereader *sort_execute_1var (struct casereader *,
  46                                       const struct variable *);
  47
  48 #endif /* math/sort.h */