math: Avoid unneeded extra allocations for fixed-size data structures.

[pspp] / src / math / interaction.h

diff --git a/src/math/interaction.h b/src/math/interaction.h
index 995d0684517d78a8207e040121126b1ae63f473c..8229083f860f7cf0a7b86e5f4268b9a1551623cf 100644 (file)
--- a/src/math/interaction.h
+++ b/src/math/interaction.h
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2009 Free Software Foundation, Inc.
+   Copyright (C) 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
@@ -14,27 +14,60 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
 
-#ifndef INTERACTION_H
-#define INTERACTION_H
-#include <data/case.h>
-
-struct interaction_variable;
-struct interaction_value;
-
-struct interaction_variable * interaction_variable_create (const struct variable **, int);
-void interaction_variable_destroy (struct interaction_variable *);
-struct interaction_value * interaction_value_create (const struct interaction_variable *, const union value **);
-void interaction_value_destroy (struct interaction_value *);
-size_t interaction_variable_get_n_vars (const struct interaction_variable *);
-double interaction_value_get_nonzero_entry (const struct interaction_value *);
-const union value *interaction_value_get (const struct interaction_value *);
-const struct variable * interaction_get_variable (const struct interaction_variable *);
-size_t interaction_get_n_numeric (const struct interaction_variable *);
-size_t interaction_get_n_alpha (const struct interaction_variable *);
-size_t interaction_get_n_vars (const struct interaction_variable *);
-const struct variable * interaction_get_member (const struct interaction_variable *, size_t);
-bool is_interaction (const struct variable *, const struct interaction_variable **, size_t);
-struct interaction_value *
-interaction_case_data (const struct ccase *, const struct interaction_variable *);
-double interaction_value_get_nonzero_entry (const struct interaction_value *);
+
+#ifndef _INTERACTION_H__
+#define _INTERACTION_H__ 1
+
+#include <stdbool.h>
+#include "libpspp/compiler.h"
+#include "data/missing-values.h"
+
+struct ccase;
+struct interaction;
+struct string;
+struct variable;
+
+#include <stddef.h>
+
+/* An interaction is a structure containing a "product" of other variables.
+   The variables can be either string or numeric.
+
+   Interaction is commutative.  That means, that from a mathematical point of
+   view, the order of the variables is irrelevant.  However, for display
+   purposes, and for matching with an interaction's value the order is
+   pertinent.  Therefore, when using these functions, make sure the orders of
+   variables and values match when appropriate.
+
+   Some functions for interactions will not work properly for interactions that
+   contain a given variable more than once, so this should be regarded as an
+   invariant.  The functions to modify interactions don't check for this
+   invariant. */
+struct interaction
+  {
+    const struct variable **vars;
+    size_t n_vars;
+  };
+
+struct interaction *interaction_create (const struct variable *);
+struct interaction *interaction_clone (const struct interaction *);
+void interaction_destroy (struct interaction *);
+void interaction_add_variable (struct interaction *, const struct variable *);
+void interaction_dump (const struct interaction *);
+void interaction_to_string (const struct interaction *, struct string *str);
+bool interaction_is_proper_subset (const struct interaction *,
+                                   const struct interaction *);
+bool interaction_is_subset (const struct interaction *,
+                            const struct interaction *);
+
+
+unsigned int interaction_case_hash (const struct interaction *,
+                                    const struct ccase *,
+                                   unsigned int base) WARN_UNUSED_RESULT;
+bool interaction_case_equal (const struct interaction *, const struct ccase *,
+                             const struct ccase *);
+bool interaction_case_is_missing (const struct interaction *,
+                                  const struct ccase *, enum mv_class);
+int interaction_case_cmp_3way (const struct interaction *,
+                               const struct ccase *, const struct ccase *);
+
 #endif