Implement DATASET commands.

[pspp] / src / data / dataset-writer.c

diff --git a/src/data/dataset-writer.c b/src/data/dataset-writer.c
new file mode 100644 (file)
index 0000000..c810cf2
--- /dev/null
+++ b/src/data/dataset-writer.c
@@ -0,0 +1,130 @@
+/* PSPP - a program for statistical analysis.
+   Copyright (C) 2006, 2009-2011 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+#include "data/dataset-writer.h"
+
+#include <stdlib.h>
+
+#include "data/case.h"
+#include "data/case-map.h"
+#include "data/casereader.h"
+#include "data/casewriter-provider.h"
+#include "data/casewriter.h"
+#include "data/dataset.h"
+#include "data/dictionary.h"
+#include "data/file-handle-def.h"
+#include "data/variable.h"
+#include "libpspp/compiler.h"
+#include "libpspp/taint.h"
+
+#include "gl/xalloc.h"
+
+#define N_(msgid) (msgid)
+
+/* A dataset file writer. */
+struct dataset_writer
+  {
+    struct dataset *ds;                 /* Underlying dataset. */
+    struct fh_lock *lock;               /* Exclusive access to file handle. */
+    struct dictionary *dict;            /* Dictionary for subwriter. */
+    struct case_map *compactor;         /* Compacts into dictionary. */
+    struct casewriter *subwriter;       /* Data output. */
+  };
+
+static const struct casewriter_class dataset_writer_casewriter_class;
+
+/* Opens FH, which must have referent type FH_REF_DATASET, and
+   returns a dataset_writer for it, or a null pointer on
+   failure.  Cases stored in the dataset_writer will be expected
+   to be drawn from DICTIONARY. */
+struct casewriter *
+dataset_writer_open (struct file_handle *fh,
+                     const struct dictionary *dictionary)
+{
+  struct dataset_writer *writer;
+  struct casewriter *casewriter;
+  struct fh_lock *lock;
+
+  /* Get exclusive write access to handle. */
+  /* TRANSLATORS: this fragment will be interpolated into
+     messages in fh_lock() that identify types of files. */
+  lock = fh_lock (fh, FH_REF_DATASET, N_("dataset"), FH_ACC_WRITE, true);
+  if (lock == NULL)
+    return NULL;
+
+  /* Create writer. */
+  writer = xmalloc (sizeof *writer);
+  writer->lock = lock;
+  writer->ds = fh_get_dataset (fh);
+
+  writer->dict = dict_clone (dictionary);
+  dict_delete_scratch_vars (writer->dict);
+  if (dict_count_values (writer->dict, 0)
+      < dict_get_next_value_idx (writer->dict))
+    {
+      writer->compactor = case_map_to_compact_dict (writer->dict, 0);
+      dict_compact_values (writer->dict);
+    }
+  else
+    writer->compactor = NULL;
+  writer->subwriter = autopaging_writer_create (dict_get_proto (writer->dict));
+
+  casewriter = casewriter_create (dict_get_proto (writer->dict),
+                                  &dataset_writer_casewriter_class, writer);
+  taint_propagate (casewriter_get_taint (writer->subwriter),
+                   casewriter_get_taint (casewriter));
+  return casewriter;
+}
+
+/* Writes case C to WRITER. */
+static void
+dataset_writer_casewriter_write (struct casewriter *w UNUSED, void *writer_,
+                                 struct ccase *c)
+{
+  struct dataset_writer *writer = writer_;
+  casewriter_write (writer->subwriter,
+                    case_map_execute (writer->compactor, c));
+}
+
+/* Closes WRITER. */
+static void
+dataset_writer_casewriter_destroy (struct casewriter *w UNUSED, void *writer_)
+{
+  struct dataset_writer *writer = writer_;
+  struct casereader *reader = casewriter_make_reader (writer->subwriter);
+  if (!casereader_error (reader))
+    {
+      dataset_set_dict (writer->ds, writer->dict);
+      dataset_set_source (writer->ds, reader);
+    }
+  else
+    {
+      casereader_destroy (reader);
+      dict_destroy (writer->dict);
+    }
+
+  fh_unlock (writer->lock);
+  free (writer);
+}
+
+static const struct casewriter_class dataset_writer_casewriter_class =
+  {
+    dataset_writer_casewriter_write,
+    dataset_writer_casewriter_destroy,
+    NULL,
+  };