hmap: New function hmap_clear().

diff --git a/src/libpspp/hmap.c b/src/libpspp/hmap.c
index 4c97e2359c922034cc8389344dc2a581227042d7..9050cc08f5571a6f2e8908201444d834a96a6398 100644 (file)
--- a/src/libpspp/hmap.c
+++ b/src/libpspp/hmap.c
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2008, 2009 Free Software Foundation, Inc.
+   Copyright (C) 2008, 2009, 2010 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
@@ -49,6 +49,18 @@ hmap_swap (struct hmap *a, struct hmap *b)
     b->buckets = &b->one;
 }
 
+/* Removes all of the elements from MAP, without destroying MAP itself and
+   without accessing the existing elements (if any). */
+void
+hmap_clear (struct hmap *map)
+{
+  size_t i;
+
+  for (i = 0; i <= map->mask; i++)
+    map->buckets[i] = NULL;
+  map->count = 0;
+}
+
 /* Frees the memory, if any, allocated by hash map MAP.  This has
    no effect on the actual data items in MAP, if any, because the
    client is responsible for allocating and freeing them.  It

diff --git a/src/libpspp/hmap.h b/src/libpspp/hmap.h
index 1592f803bedb17bd9c1ca4dc285f5bd6e72fd1c4..095edf104674ba0af56b2a2da7d0bb4687807c0d 100644 (file)
--- a/src/libpspp/hmap.h
+++ b/src/libpspp/hmap.h
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2008, 2009 Free Software Foundation, Inc.
+   Copyright (C) 2008, 2009, 2010 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
@@ -158,6 +158,7 @@ struct hmap
 /* Creation and destruction. */
 void hmap_init (struct hmap *);
 void hmap_swap (struct hmap *, struct hmap *);
+void hmap_clear (struct hmap *);
 void hmap_destroy (struct hmap *);
 
 /* Storage management. */

diff --git a/tests/libpspp/hmap-test.c b/tests/libpspp/hmap-test.c
index f9d963d83bca459067d6fbcaea96a3355089f665..bbe341388a3ce530b26957afd8e89a3df586d6c1 100644 (file)
--- a/tests/libpspp/hmap-test.c
+++ b/tests/libpspp/hmap-test.c
@@ -915,6 +915,45 @@ test_swap_random_hash (void)
   test_swap (128, random_hash);
 }
 
+/* Inserts elements into an hmap in ascending order, then clears the hash table
+   using hmap_clear(). */
+static void
+test_clear (void)
+{
+  const int max_elems = 128;
+  struct element *elements;
+  int *values;
+  struct hmap hmap;
+  int cnt;
+
+#if __GNUC__ == 4 && __GNUC_MINOR__ == 3
+  return;
+#endif  /* GCC 4.3 */
+
+  elements = xnmalloc (max_elems, sizeof *elements);
+  values = xnmalloc (max_elems, sizeof *values);
+
+  for (cnt = 0; cnt <= max_elems; cnt++)
+    {
+      int i;
+
+      hmap_init (&hmap);
+      for (i = 0; i < cnt; i++)
+        {
+          values[i] = elements[i].data = i;
+          hmap_insert (&hmap, &elements[i].node,
+                       random_hash (elements[i].data));
+          check_hmap (&hmap, values, i + 1, random_hash);
+        }
+      hmap_clear (&hmap);
+      check_hmap (&hmap, NULL, 0, random_hash);
+      hmap_destroy (&hmap);
+    }
+
+  free (elements);
+  free (values);
+}
+
 static void
 test_destroy_null (void) 
 {
@@ -999,6 +1038,8 @@ main (void)
 
   run_test (test_swap_random_hash, "test swapping tables");
 
+  run_test (test_clear, "test clearing hash table");
+
   run_test (test_destroy_null, "test destroying null table");
   run_test (test_shrink_empty, "test shrinking an empty table");