Make "internal variables" part of a dictionary.

[pspp] / src / data / dictionary.c

diff --git a/src/data/dictionary.c b/src/data/dictionary.c
index bca92dabe300b4c34439845c47abf485c900a778..6e6ab1edb4b1b0654390855fc2990a4599876596 100644 (file)
--- a/src/data/dictionary.c
+++ b/src/data/dictionary.c
@@ -1474,4 +1474,52 @@ dict_var_display_width_changed (const struct variable *v)
        d->callbacks->var_display_width_changed (d, var_get_dict_index (v), d->cb_data);
     }
 }
+\f
+/* Dictionary used to contain "internal variables". */
+static struct dictionary *internal_dict;
+
+/* Create a variable of the specified WIDTH to be used for internal
+   calculations only.  The variable is assigned case index CASE_IDX. */
+struct variable *
+dict_create_internal_var (int case_idx, int width)
+{
+  if (internal_dict == NULL)
+    internal_dict = dict_create ();
+
+  for (;;)
+    {
+      static int counter = INT_MAX / 2;
+      struct variable *var;
+      char name[64];
+
+      if (++counter == INT_MAX)
+        counter = INT_MAX / 2;
+
+      sprintf (name, "$internal%d", counter);
+      var = dict_create_var (internal_dict, name, width);
+      if (var != NULL)
+        {
+          set_var_case_index (var, case_idx);
+          return var;
+        }
+    }
+}
+
+/* Destroys VAR, which must have been created with
+   dict_create_internal_var(). */
+void
+dict_destroy_internal_var (struct variable *var)
+{
+  if (var != NULL)
+    {
+      dict_delete_var (internal_dict, var);
 
+      /* Destroy internal_dict if it has no variables left, just so that
+         valgrind --leak-check --show-reachable won't show internal_dict. */
+      if (dict_get_var_cnt (internal_dict) == 0)
+        {
+          dict_destroy (internal_dict);
+          internal_dict = NULL;
+        }
+    }
+}