X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fdata%2Fcasegrouper.c;h=8a4f05b318faa2874dab7d1e695a9d9901ab94c6;hb=9f4661992f4b481c6dafa6fd53c94ecfe7b3af8c;hp=f2815106ea6330bac01609c40ae310be8cc808da;hpb=f5c108becd49d78f4898cab11352291f5689d24e;p=pspp-builds.git
diff --git a/src/data/casegrouper.c b/src/data/casegrouper.c
index f2815106..8a4f05b3 100644
--- a/src/data/casegrouper.c
+++ b/src/data/casegrouper.c
@@ -1,20 +1,18 @@
-/* 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 . */
#include
@@ -30,16 +28,27 @@
#include "xalloc.h"
+/* A casegrouper. */
struct casegrouper
{
- struct casereader *reader;
- struct taint *taint;
+ struct casereader *reader; /* Source of input cases. */
+ struct taint *taint; /* Error status for casegrouper. */
+ /* Functions for grouping cases. */
bool (*same_group) (const struct ccase *, const struct ccase *, void *aux);
void (*destroy) (void *aux);
void *aux;
};
+/* Creates and returns a new casegrouper that takes its input
+ from READER. SAME_GROUP is used to decide which cases are in
+ a group: it returns true if the pair of cases provided are in
+ the same group, false otherwise. DESTROY will be called when
+ the casegrouper is destroyed and should free any storage
+ needed by SAME_GROUP.
+
+ SAME_GROUP may be a null pointer. If so, READER's entire
+ contents is considered to be a single group. */
struct casegrouper *
casegrouper_create_func (struct casereader *reader,
bool (*same_group) (const struct ccase *,
@@ -57,13 +66,17 @@ casegrouper_create_func (struct casereader *reader,
return grouper;
}
-/* FIXME: we really shouldn't need a temporary casewriter for the
- common case where we read an entire group's data before going
- on to the next. */
+/* Obtains the next group of cases from GROUPER. Returns true if
+ successful, false if no groups remain. If successful, *READER
+ is set to the casereader for the new group; otherwise, it is
+ set to NULL. */
bool
casegrouper_get_next_group (struct casegrouper *grouper,
struct casereader **reader)
{
+ /* FIXME: we really shouldn't need a temporary casewriter for
+ the common case where we read an entire group's data before
+ going on to the next. */
if (grouper->same_group != NULL)
{
struct casewriter *writer;
@@ -102,10 +115,17 @@ casegrouper_get_next_group (struct casegrouper *grouper,
return true;
}
else
- return false;
+ {
+ *reader = NULL;
+ return false;
+ }
}
}
+/* Destroys GROUPER. Returns false if GROUPER's input casereader
+ or any state derived from it had become tainted, which means
+ that an I/O error or other serious error occurred in
+ processing data derived from GROUPER; otherwise, return true. */
bool
casegrouper_destroy (struct casegrouper *grouper)
{
@@ -126,29 +146,26 @@ casegrouper_destroy (struct casegrouper *grouper)
else
return true;
}
+
+/* Casegrouper based on equal values of variables from case to
+ case. */
+/* Casegrouper based on equal variables. */
struct casegrouper_vars
{
- const struct variable **vars;
- size_t var_cnt;
+ const struct variable **vars; /* Variables to compare. */
+ size_t var_cnt; /* Number of variables. */
};
-static bool
-casegrouper_vars_same_group (const struct ccase *a, const struct ccase *b,
- void *cv_)
-{
- struct casegrouper_vars *cv = cv_;
- return case_compare (a, b, cv->vars, cv->var_cnt) == 0;
-}
-
-static void
-casegrouper_vars_destroy (void *cv_)
-{
- struct casegrouper_vars *cv = cv_;
- free (cv->vars);
- free (cv);
-}
+static bool casegrouper_vars_same_group (const struct ccase *,
+ const struct ccase *,
+ void *);
+static void casegrouper_vars_destroy (void *);
+/* Creates and returns a casegrouper that reads data from READER
+ and breaks it into contiguous groups of cases that have equal
+ values for the VAR_CNT variables in VARS. If VAR_CNT is 0,
+ then all the cases will be put in a single group. */
struct casegrouper *
casegrouper_create_vars (struct casereader *reader,
const struct variable *const *vars,
@@ -168,6 +185,11 @@ casegrouper_create_vars (struct casereader *reader,
return casegrouper_create_func (reader, NULL, NULL, NULL);
}
+/* Creates and returns a casegrouper that reads data from READER
+ and breaks it into contiguous groups of cases that have equal
+ values for the SPLIT FILE variables in DICT. If DICT has no
+ SPLIT FILE variables, then all the cases will be put into a
+ single group. */
struct casegrouper *
casegrouper_create_splits (struct casereader *reader,
const struct dictionary *dict)
@@ -177,6 +199,11 @@ casegrouper_create_splits (struct casereader *reader,
dict_get_split_cnt (dict));
}
+/* Creates and returns a casegrouper that reads data from READER
+ and breaks it into contiguous groups of cases that have equal
+ values for the variables used for sorting in CO. If CO is
+ empty (contains no sort keys), then all the cases will be put
+ into a single group. */
struct casegrouper *
casegrouper_create_case_ordering (struct casereader *reader,
const struct case_ordering *co)
@@ -191,3 +218,22 @@ casegrouper_create_case_ordering (struct casereader *reader,
return grouper;
}
+
+/* "same_group" function for an equal-variables casegrouper. */
+static bool
+casegrouper_vars_same_group (const struct ccase *a, const struct ccase *b,
+ void *cv_)
+{
+ struct casegrouper_vars *cv = cv_;
+ return case_compare (a, b, cv->vars, cv->var_cnt) == 0;
+}
+
+/* "destroy" for an equal-variables casegrouper. */
+static void
+casegrouper_vars_destroy (void *cv_)
+{
+ struct casegrouper_vars *cv = cv_;
+ free (cv->vars);
+ free (cv);
+}
+