/* PSPP - a program for statistical analysis.
- Copyright (C) 1997-9, 2000, 2006, 2007 Free Software Foundation, Inc.
+ Copyright (C) 1997-9, 2000, 2006, 2007, 2009 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
#include <data/case-map.h>
#include <stdio.h>
+#include <stdlib.h>
+#include <data/casereader.h>
+#include <data/casewriter.h>
#include <data/dictionary.h>
#include <data/variable.h>
#include <data/case.h>
-#include <libpspp/alloc.h>
#include <libpspp/assertion.h>
+#include "xalloc.h"
+
/* A case map. */
struct case_map
{
corresponding source index. */
};
+static struct ccase *translate_case (struct ccase *, void *map_);
+static bool destroy_case_map (void *map_);
+
/* Creates and returns an empty map. */
static struct case_map *
create_case_map (size_t n)
}
}
-/* Maps from SRC to DST, applying case map MAP. */
-void
-case_map_execute (const struct case_map *map,
- const struct ccase *src, struct ccase *dst)
-{
- size_t dst_idx;
+/* If MAP is nonnull, returns a new case that is the result of
+ applying case map MAP to SRC, and unrefs SRC.
- case_create (dst, map->value_cnt);
- for (dst_idx = 0; dst_idx < map->value_cnt; dst_idx++)
+ If MAP is null, returns SRC unchanged. */
+struct ccase *
+case_map_execute (const struct case_map *map, struct ccase *src)
+{
+ if (map != NULL)
{
- int src_idx = map->map[dst_idx];
- if (src_idx != -1)
- *case_data_rw_idx (dst, dst_idx) = *case_data_idx (src, src_idx);
+ struct ccase *dst;
+ size_t dst_idx;
+
+ dst = case_create (map->value_cnt);
+ for (dst_idx = 0; dst_idx < map->value_cnt; dst_idx++)
+ {
+ int src_idx = map->map[dst_idx];
+ if (src_idx != -1)
+ *case_data_rw_idx (dst, dst_idx) = *case_data_idx (src, src_idx);
+ }
+ case_unref (src);
+ return dst;
}
+ else
+ return src;
}
/* Returns the number of `union value's in cases created by
return map->value_cnt;
}
+/* Creates and returns a new casereader whose cases are produced
+ by reading from SUBREADER and executing the actions of MAP.
+ The casereader will have as many `union value's as MAP. When
+ the new casereader is destroyed, MAP will be destroyed too.
+
+ After this function is called, SUBREADER must not ever again
+ be referenced directly. It will be destroyed automatically
+ when the returned casereader is destroyed. */
+struct casereader *
+case_map_create_input_translator (struct case_map *map,
+ struct casereader *subreader)
+{
+ return casereader_create_translator (subreader,
+ case_map_get_value_cnt (map),
+ translate_case,
+ destroy_case_map,
+ map);
+}
+
+/* Creates and returns a new casewriter. Cases written to the
+ new casewriter will be passed through MAP and written to
+ SUBWRITER. The casewriter will have as many `union value's as
+ MAP. When the new casewriter is destroyed, MAP will be
+ destroyed too.
+
+ After this function is called, SUBWRITER must not ever again
+ be referenced directly. It will be destroyed automatically
+ when the returned casewriter is destroyed. */
+struct casewriter *
+case_map_create_output_translator (struct case_map *map,
+ struct casewriter *subwriter)
+{
+ return casewriter_create_translator (subwriter,
+ case_map_get_value_cnt (map),
+ translate_case,
+ destroy_case_map,
+ map);
+}
+
+/* Casereader/casewriter translation callback. */
+static struct ccase *
+translate_case (struct ccase *input, void *map_)
+{
+ struct case_map *map = map_;
+ return case_map_execute (map, input);
+}
+
+/* Casereader/casewriter destruction callback. */
+static bool
+destroy_case_map (void *map_)
+{
+ struct case_map *map = map_;
+ case_map_destroy (map);
+ return true;
+}
+
/* Creates and returns a case_map that can be used to compact
cases for dictionary D.