Added new files resulting from directory restructuring.

[pspp-builds.git] / src / data / scratch-reader.c

diff --git a/src/data/scratch-reader.c b/src/data/scratch-reader.c
new file mode 100644 (file)
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+++ b/src/data/scratch-reader.c
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+/* PSPP - computes sample statistics.
+   Copyright (C) 2006 Free Software Foundation, Inc.
+   Written by Ben Pfaff <blp@gnu.org>.
+
+   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 2 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, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+   02110-1301, USA. */
+
+#include <config.h>
+#include "scratch-reader.h"
+#include <stdlib.h>
+#include "casefile.h"
+#include "dictionary.h"
+#include "message.h"
+#include "file-handle-def.h"
+#include "scratch-handle.h"
+#include "xalloc.h"
+
+#include "gettext.h"
+#define _(msgid) gettext (msgid)
+
+/* A reader for a scratch file. */
+struct scratch_reader 
+  {
+    struct file_handle *fh;             /* Underlying file handle. */
+    struct casereader *casereader;      /* Case reader. */
+  };
+
+/* Opens FH, which must have referent type FH_REF_SCRATCH, and
+   returns a scratch_reader for it, or a null pointer on
+   failure.  Stores the dictionary for the scratch file into
+   *DICT.
+
+   If you use an any_reader instead, then your code can be more
+   flexible without being any harder to write. */
+struct scratch_reader *
+scratch_reader_open (struct file_handle *fh, struct dictionary **dict)
+{
+  struct scratch_handle *sh;
+  struct scratch_reader *reader;
+  
+  if (!fh_open (fh, FH_REF_SCRATCH, "scratch file", "rs"))
+    return NULL;
+  
+  sh = fh_get_scratch_handle (fh);
+  if (sh == NULL) 
+    {
+      msg (SE, _("Scratch file handle %s has not yet been written, "
+                 "using SAVE or another procedure, so it cannot yet "
+                 "be used for reading."),
+           fh_get_name (fh));
+      return NULL;
+    }
+
+  *dict = dict_clone (sh->dictionary);
+  reader = xmalloc (sizeof *reader);
+  reader->fh = fh;
+  reader->casereader = casefile_get_reader (sh->casefile);
+  return reader;
+}
+
+/* Reads a case from READER into C.
+   Returns true if successful, false on error or at end of file. */
+bool
+scratch_reader_read_case (struct scratch_reader *reader, struct ccase *c)
+{
+  return casereader_read (reader->casereader, c);
+}
+
+/* Returns true if an I/O error occurred on READER, false otherwise. */
+bool
+scratch_reader_error (const struct scratch_reader *reader) 
+{
+  return casefile_error (casereader_get_casefile (reader->casereader));
+}
+
+/* Closes READER. */
+void
+scratch_reader_close (struct scratch_reader *reader) 
+{
+  fh_close (reader->fh, "scratch file", "rs");
+  casereader_destroy (reader->casereader);
+  free (reader);
+}