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 case_map *compactor;         /* Compacts into dictionary. */
  46     struct casewriter *subwriter;       /* Data output. */
  47   };
  48
  49 static const struct casewriter_class dataset_writer_casewriter_class;
  50
  51 /* Opens FH, which must have referent type FH_REF_DATASET, and
  52    returns a dataset_writer for it, or a null pointer on
  53    failure.  Cases stored in the dataset_writer will be expected
  54    to be drawn from DICTIONARY. */
  55 struct casewriter *
  56 dataset_writer_open (struct file_handle *fh,
  57                      const struct dictionary *dictionary)
  58 {
  59   struct dataset_writer *writer;
  60   struct casewriter *casewriter;
  61   struct fh_lock *lock;
  62
  63   /* Get exclusive write access to handle. */
  64   /* TRANSLATORS: this fragment will be interpolated into
  65      messages in fh_lock() that identify types of files. */
  66   lock = fh_lock (fh, FH_REF_DATASET, N_("dataset"), FH_ACC_WRITE, true);
  67   if (lock == NULL)
  68     return NULL;
  69
  70   /* Create writer. */
  71   writer = xmalloc (sizeof *writer);
  72   writer->lock = lock;
  73   writer->ds = fh_get_dataset (fh);
  74
  75   writer->dict = dict_clone (dictionary);
  76   dict_delete_scratch_vars (writer->dict);
  77   if (dict_count_values (writer->dict, 0)
  78       < dict_get_next_value_idx (writer->dict))
  79     {
  80       writer->compactor = case_map_to_compact_dict (writer->dict, 0);
  81       dict_compact_values (writer->dict);
  82     }
  83   else
  84     writer->compactor = NULL;
  85   writer->subwriter = autopaging_writer_create (dict_get_proto (writer->dict));
  86
  87   casewriter = casewriter_create (dict_get_proto (writer->dict),
  88                                   &dataset_writer_casewriter_class, writer);
  89   taint_propagate (casewriter_get_taint (writer->subwriter),
  90                    casewriter_get_taint (casewriter));
  91   return casewriter;
  92 }
  93
  94 /* Writes case C to WRITER. */
  95 static void
  96 dataset_writer_casewriter_write (struct casewriter *w UNUSED, void *writer_,
  97                                  struct ccase *c)
  98 {
  99   struct dataset_writer *writer = writer_;
 100   casewriter_write (writer->subwriter,
 101                     case_map_execute (writer->compactor, c));
 102 }
 103
 104 /* Closes WRITER. */
 105 static void
 106 dataset_writer_casewriter_destroy (struct casewriter *w UNUSED, void *writer_)
 107 {
 108   struct dataset_writer *writer = writer_;
 109   struct casereader *reader = casewriter_make_reader (writer->subwriter);
 110   if (!casereader_error (reader))
 111     {
 112       dataset_set_dict (writer->ds, writer->dict);
 113       dataset_set_source (writer->ds, reader);
 114     }
 115   else
 116     {
 117       casereader_destroy (reader);
 118       dict_destroy (writer->dict);
 119     }
 120
 121   fh_unlock (writer->lock);
 122   free (writer);
 123 }
 124
 125 static const struct casewriter_class dataset_writer_casewriter_class =
 126   {
 127     dataset_writer_casewriter_write,
 128     dataset_writer_casewriter_destroy,
 129     NULL,
 130   };