X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fdata%2Fcasereader-translator.c;h=062184691defe569321351b5f1304709fcfb2273;hb=81579d9e9f994fb2908f50af41c3eb033d216e58;hp=feffa15c4510ba97e57cd95705cd9afd290c1e04;hpb=b5c82cc9aabe7e641011130240ae1b2e84348e23;p=pspp-builds.git
diff --git a/src/data/casereader-translator.c b/src/data/casereader-translator.c
index feffa15c..06218469 100644
--- a/src/data/casereader-translator.c
+++ b/src/data/casereader-translator.c
@@ -1,5 +1,5 @@
/* PSPP - a program for statistical analysis.
- Copyright (C) 2007, 2009 Free Software Foundation, Inc.
+ Copyright (C) 2007, 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
@@ -15,15 +15,16 @@
along with this program. If not, see . */
#include
-#include
-#include
+
#include
-#include
-#include
-#include
+#include "data/casereader-provider.h"
+#include "data/casereader.h"
+#include "data/val-type.h"
+#include "data/variable.h"
+#include "libpspp/taint.h"
-#include "xalloc.h"
+#include "gl/xalloc.h"
/* Casereader that applies a user-supplied function to translate
each case into another in an arbitrary fashion. */
@@ -46,6 +47,11 @@ static const struct casereader_class casereader_translator_class;
INPUT and auxiliary data AUX. TRANSLATE must destroy its
input case.
+ TRANSLATE may be stateful, that is, the output for a given
+ case may depend on previous cases. If TRANSLATE is stateless,
+ then you may want to use casereader_translate_stateless
+ instead, since it sometimes performs better.
+
The cases returned by TRANSLATE must match OUTPUT_PROTO.
When the translating casereader is destroyed, DESTROY will be
@@ -106,7 +112,110 @@ static const struct casereader_class casereader_translator_class =
NULL,
NULL,
};
+
+/* Casereader that applies a user-supplied function to translate
+ each case into another in a stateless fashion. */
+
+/* A statelessly translating casereader. */
+struct casereader_stateless_translator
+ {
+ struct casereader *subreader; /* Source of input cases. */
+
+ casenumber case_offset;
+ struct ccase *(*translate) (struct ccase *input, casenumber,
+ const void *aux);
+ bool (*destroy) (void *aux);
+ void *aux;
+ };
+static const struct casereader_random_class
+casereader_stateless_translator_class;
+
+/* Creates and returns a new casereader whose cases are produced by reading
+ from SUBREADER and passing through the TRANSLATE function. TRANSLATE must
+ takes ownership of its input case and returns a translated case, populating
+ the translated case based on INPUT and auxiliary data AUX.
+
+ TRANSLATE must be stateless, that is, the output for a given case must not
+ depend on previous cases. This is because cases may be retrieved in
+ arbitrary order, and some cases may be retrieved multiple times, and some
+ cases may be skipped and never retrieved at all. If TRANSLATE is stateful,
+ use casereader_create_translator instead.
+
+ The casenumber argument to the TRANSLATE function is the absolute case
+ number in SUBREADER, that is, 0 when the first case in SUBREADER is being
+ translated, 1 when the second case is being translated, and so on.
+
+ The cases returned by TRANSLATE must match OUTPUT_PROTO.
+
+ When the stateless translating casereader is destroyed, DESTROY will be
+ called to allow any auxiliary data 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_translate_stateless (
+ struct casereader *subreader,
+ const struct caseproto *output_proto,
+ struct ccase *(*translate) (struct ccase *input, casenumber,
+ const void *aux),
+ bool (*destroy) (void *aux),
+ void *aux)
+{
+ struct casereader_stateless_translator *cst = xmalloc (sizeof *cst);
+ struct casereader *reader;
+ cst->subreader = casereader_rename (subreader);
+ cst->translate = translate;
+ cst->destroy = destroy;
+ cst->aux = aux;
+ reader = casereader_create_random (
+ output_proto, casereader_get_case_cnt (cst->subreader),
+ &casereader_stateless_translator_class, cst);
+ taint_propagate (casereader_get_taint (cst->subreader),
+ casereader_get_taint (reader));
+ return reader;
+}
+
+/* Internal read function for stateless translating casereader. */
+static struct ccase *
+casereader_stateless_translator_read (struct casereader *reader UNUSED,
+ void *cst_, casenumber idx)
+{
+ struct casereader_stateless_translator *cst = cst_;
+ struct ccase *tmp = casereader_peek (cst->subreader, idx);
+ if (tmp != NULL)
+ tmp = cst->translate (tmp, cst->case_offset + idx, cst->aux);
+ return tmp;
+}
+
+/* Internal destroy function for translating casereader. */
+static void
+casereader_stateless_translator_destroy (struct casereader *reader UNUSED,
+ void *cst_)
+{
+ struct casereader_stateless_translator *cst = cst_;
+ casereader_destroy (cst->subreader);
+ cst->destroy (cst->aux);
+ free (cst);
+}
+
+static void
+casereader_stateless_translator_advance (struct casereader *reader UNUSED,
+ void *cst_, casenumber cnt)
+{
+ struct casereader_stateless_translator *cst = cst_;
+ cst->case_offset += casereader_advance (cst->subreader, cnt);
+}
+
+/* Casereader class for stateless translating casereader. */
+static const struct casereader_random_class
+casereader_stateless_translator_class =
+ {
+ casereader_stateless_translator_read,
+ casereader_stateless_translator_destroy,
+ casereader_stateless_translator_advance,
+ };
struct casereader_append_numeric
@@ -382,7 +491,7 @@ uniquify (const struct ccase *c, void *aux)
const union value *current_value = case_data (c, cdr->key);
const int key_width = var_get_width (cdr->key);
const double weight = cdr->weight ? case_data (c, cdr->weight)->f : 1.0;
- const struct ccase *next_case = casereader_peek (cdr->clone, cdr->n + 1);
+ struct ccase *next_case = casereader_peek (cdr->clone, cdr->n + 1);
int dir = 0;
cdr->n ++;
@@ -393,6 +502,7 @@ uniquify (const struct ccase *c, void *aux)
dir = value_compare_3way (case_data (next_case, cdr->key),
current_value, key_width);
+ case_unref (next_case);
if ( dir != 0 )
{
/* Insist that the data are sorted */