-/* PSPP - computes sample statistics.
+/* PSPP - a program for statistical analysis.
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 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.
+ 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. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
#include "xalloc.h"
+/* Casereader that applies a user-supplied function to translate
+ each case into another in an arbitrary fashion. */
+
+/* A translating casereader. */
struct casereader_translator
{
- struct casereader *subreader;
+ struct casereader *subreader; /* Source of input cases. */
- void (*translate) (const struct ccase *input, struct ccase *output,
- void *aux);
+ void (*translate) (struct ccase *input, struct ccase *output, void *aux);
bool (*destroy) (void *aux);
void *aux;
};
-static struct casereader_class casereader_translator_class;
+static const struct casereader_class casereader_translator_class;
+
+/* Creates and returns a new casereader whose cases are produced
+ by reading from SUBREADER and passing through TRANSLATE, which
+ must create case OUTPUT, with OUTPUT_VALUE_CNT values, and
+ populate it based on INPUT and auxiliary data AUX. TRANSLATE
+ must also destroy INPUT.
+
+ When the translating casereader is destroyed, DESTROY will be
+ called to allow any state maintained by TRANSLATE to be freed.
+ After this function is called, SUBREADER must not ever again
+ be referenced directly. It will be destroyed automatically
+ when the translating casereader is destroyed. */
struct casereader *
casereader_create_translator (struct casereader *subreader,
size_t output_value_cnt,
- void (*translate) (const struct ccase *input,
+ void (*translate) (struct ccase *input,
struct ccase *output,
void *aux),
bool (*destroy) (void *aux),
- void *aux)
+ void *aux)
{
struct casereader_translator *ct = xmalloc (sizeof *ct);
struct casereader *reader;
return reader;
}
+/* Internal read function for translating casereader. */
static bool
casereader_translator_read (struct casereader *reader UNUSED,
- void *ct_, struct ccase *c)
+ void *ct_, struct ccase *c)
{
struct casereader_translator *ct = ct_;
struct ccase tmp;
- if (casereader_read (ct->subreader, &tmp))
+ if (casereader_read (ct->subreader, &tmp))
{
ct->translate (&tmp, c, ct->aux);
- return true;
+ return true;
}
else
return false;
}
+/* Internal destroy function for translating casereader. */
static void
-casereader_translator_destroy (struct casereader *reader UNUSED, void *ct_)
+casereader_translator_destroy (struct casereader *reader UNUSED, void *ct_)
{
struct casereader_translator *ct = ct_;
casereader_destroy (ct->subreader);
free (ct);
}
-static struct casereader_class casereader_translator_class =
+/* Casereader class for translating casereader. */
+static const struct casereader_class casereader_translator_class =
{
casereader_translator_read,
casereader_translator_destroy,
NULL,
NULL,
};
+\f
+struct casereader_arithmetic_sequence
+ {
+ int value_ofs;
+ double first;
+ double increment;
+ casenumber n;
+ };
+
+static void cas_translate (struct ccase *input, struct ccase *output,
+ void *aux);
+static bool cas_destroy (void *aux);
+
+/* Creates and returns a new casereader whose cases are produced
+ by reading from SUBREADER and appending an additional value,
+ which takes the value FIRST in the first case, FIRST +
+ INCREMENT in the second case, FIRST + INCREMENT * 2 in the
+ third case, and so on.
+
+ After this function is called, SUBREADER must not ever again
+ be referenced directly. It will be destroyed automatically
+ when the translating casereader is destroyed. */
+struct casereader *
+casereader_create_arithmetic_sequence (struct casereader *subreader,
+ double first, double increment)
+{
+ /* This could be implemented with a great deal more efficiency
+ and generality. However, this implementation is easy. */
+ struct casereader_arithmetic_sequence *cas = xmalloc (sizeof *cas);
+ cas->value_ofs = casereader_get_value_cnt (subreader);
+ cas->first = first;
+ cas->increment = increment;
+ cas->n = 0;
+ return casereader_create_translator (subreader, cas->value_ofs + 1,
+ cas_translate, cas_destroy, cas);
+}
+
+static void
+cas_translate (struct ccase *input, struct ccase *output, void *cas_)
+{
+ struct casereader_arithmetic_sequence *cas = cas_;
+ case_nullify (output);
+ case_move (output, input);
+ case_resize (output, cas->value_ofs + 1);
+ case_data_rw_idx (output, cas->value_ofs)->f
+ = cas->first + cas->increment * cas->n++;
+}
+
+static bool
+cas_destroy (void *cas_)
+{
+ struct casereader_arithmetic_sequence *cas = cas_;
+ free (cas);
+ return true;
+}
projects / pspp-builds.git / blobdiff