Add casereaders and casewriters, the basis of the new data processing

[pspp] / src / data / casewriter-translator.c

diff --git a/src/data/casewriter-translator.c b/src/data/casewriter-translator.c
new file mode 100644 (file)
index 0000000..0f47f76
--- /dev/null
+++ b/src/data/casewriter-translator.c
@@ -0,0 +1,98 @@
+/* PSPP - computes sample statistics.
+   Copyright (C) 2007 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 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 <data/casewriter.h>
+#include <data/casewriter-provider.h>
+
+#include <stdlib.h>
+
+#include <libpspp/taint.h>
+
+#include "xalloc.h"
+
+struct casewriter_translator
+  {
+    struct casewriter *subwriter;
+
+    void (*translate) (const struct ccase *input, struct ccase *output,
+                       void *aux);
+    bool (*destroy) (void *aux);
+    void *aux;
+  };
+
+static struct casewriter_class casewriter_translator_class;
+
+struct casewriter *
+casewriter_create_translator (struct casewriter *subwriter,
+                              void (*translate) (const struct ccase *input,
+                                                 struct ccase *output,
+                                                 void *aux),
+                              bool (*destroy) (void *aux),
+                              void *aux) 
+{
+  struct casewriter_translator *ct = xmalloc (sizeof *ct);
+  struct casewriter *writer;
+  ct->subwriter = casewriter_rename (subwriter);
+  ct->translate = translate;
+  ct->destroy = destroy;
+  ct->aux = aux;
+  writer = casewriter_create (&casewriter_translator_class, ct);
+  taint_propagate (casewriter_get_taint (ct->subwriter),
+                   casewriter_get_taint (writer));
+  return writer;
+}
+
+static void
+casewriter_translator_write (struct casewriter *writer UNUSED,
+                             void *ct_, struct ccase *c) 
+{
+  struct casewriter_translator *ct = ct_;
+  struct ccase tmp;
+
+  ct->translate (c, &tmp, ct->aux);
+  casewriter_write (ct->subwriter, &tmp);
+}
+
+static void
+casewriter_translator_destroy (struct casewriter *writer UNUSED, void *ct_) 
+{
+  struct casewriter_translator *ct = ct_;
+  casewriter_destroy (ct->subwriter);
+  ct->destroy (ct->aux);
+  free (ct);
+}
+
+static struct casereader *
+casewriter_translator_convert_to_reader (struct casewriter *writer UNUSED,
+                                         void *ct_)
+{
+  struct casewriter_translator *ct = ct_;
+  struct casereader *reader = casewriter_make_reader (ct->subwriter);
+  free (ct);
+  ct->destroy (ct->aux);
+  return reader;
+}
+
+static struct casewriter_class casewriter_translator_class = 
+  {
+    casewriter_translator_write,
+    casewriter_translator_destroy,
+    casewriter_translator_convert_to_reader,
+  };