pintos-os.org Git - pspp/blob - src/data/dataset-writer.c

   1 /* PSPP - a program for statistical analysis.
   2    Copyright (C) 2006, 2009-2011 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 #include <config.h>
  18
  19 #include "data/dataset-writer.h"
  20
  21 #include <stdlib.h>
  22
  23 #include "data/case.h"
  24 #include "data/case-map.h"
  25 #include "data/casereader.h"
  26 #include "data/casewriter-provider.h"
  27 #include "data/casewriter.h"
  28 #include "data/dataset.h"
  29 #include "data/dictionary.h"
  30 #include "data/file-handle-def.h"
  31 #include "data/variable.h"
  32 #include "libpspp/compiler.h"
  33 #include "libpspp/taint.h"
  34
  35 #include "gl/xalloc.h"
  36
  37 #define N_(msgid) (msgid)
  38
  39 /* A dataset file writer. */
  40 struct dataset_writer
  41   {
  42     struct dataset *ds;                 /* Underlying dataset. */
  43     struct fh_lock *lock;               /* Exclusive access to file handle. */
  44     struct dictionary *dict;            /* Dictionary for subwriter. */
  45     struct casewriter *subwriter;       /* Data output. */
  46   };
  47
  48 static const struct casewriter_class dataset_writer_casewriter_class;
  49
  50 /* Opens FH, which must have referent type FH_REF_DATASET, and
  51    returns a dataset_writer for it, or a null pointer on
  52    failure.  Cases stored in the dataset_writer will be expected
  53    to be drawn from DICTIONARY. */
  54 struct casewriter *
  55 dataset_writer_open (struct file_handle *fh,
  56                      const struct dictionary *dictionary)
  57 {
  58   struct dataset_writer *writer;
  59   struct casewriter *casewriter;
  60   struct fh_lock *lock;
  61
  62   /* Get exclusive write access to handle. */
  63   /* TRANSLATORS: this fragment will be interpolated into
  64      messages in fh_lock() that identify types of files. */
  65   lock = fh_lock (fh, FH_REF_DATASET, N_("dataset"), FH_ACC_WRITE, true);
  66   if (lock == NULL)
  67     return NULL;
  68
  69   /* Create writer. */
  70   writer = xmalloc (sizeof *writer);
  71   writer->lock = lock;
  72   writer->ds = fh_get_dataset (fh);
  73
  74   writer->dict = dict_clone (dictionary);
  75   struct case_map_stage *stage = case_map_stage_create (writer->dict);
  76   dict_delete_scratch_vars (writer->dict);
  77   writer->subwriter = case_map_create_output_translator (
  78     case_map_stage_to_case_map (stage),
  79     autopaging_writer_create (dict_get_proto (writer->dict)));
  80
  81   casewriter = casewriter_create (dict_get_proto (writer->dict),
  82                                   &dataset_writer_casewriter_class, writer);
  83   taint_propagate (casewriter_get_taint (writer->subwriter),
  84                    casewriter_get_taint (casewriter));
  85   return casewriter;
  86 }
  87
  88 /* Writes case C to WRITER. */
  89 static void
  90 dataset_writer_casewriter_write (struct casewriter *w UNUSED, void *writer_,
  91                                  struct ccase *c)
  92 {
  93   struct dataset_writer *writer = writer_;
  94   casewriter_write (writer->subwriter, c);
  95 }
  96
  97 /* Closes WRITER. */
  98 static void
  99 dataset_writer_casewriter_destroy (struct casewriter *w UNUSED, void *writer_)
 100 {
 101   struct dataset_writer *writer = writer_;
 102   struct casereader *reader = casewriter_make_reader (writer->subwriter);
 103   if (!casereader_error (reader))
 104     {
 105       dataset_set_dict (writer->ds, writer->dict);
 106       dataset_set_source (writer->ds, reader);
 107     }
 108   else
 109     {
 110       casereader_destroy (reader);
 111       dict_unref (writer->dict);
 112     }
 113
 114   fh_unlock (writer->lock);
 115   free (writer);
 116 }
 117
 118 static const struct casewriter_class dataset_writer_casewriter_class =
 119   {
 120     dataset_writer_casewriter_write,
 121     dataset_writer_casewriter_destroy,
 122     NULL,
 123   };