val_labs_equal: Accept null pointers

[pspp] / src / data / value-labels.c

diff --git a/src/data/value-labels.c b/src/data/value-labels.c
index 6d7f19c17d7ee191862b29c454c7ef62540a8ad5..c405961f29d69b29a24b767b0095c5029932425d 100644 (file)
--- a/src/data/value-labels.c
+++ b/src/data/value-labels.c
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 1997-9, 2000, 2009, 2010, 2011 Free Software Foundation, Inc.
+   Copyright (C) 1997-9, 2000, 2009, 2010, 2011, 2012 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
@@ -231,21 +231,59 @@ val_labs_find (const struct val_labs *vls, const union value *value)
   return label ? label->label : NULL;
 }
 
+/* Searches VLS for a value label for VALUE.  If successful,
+   returns the value label; otherwise, returns a null pointer.
+   Returns a null pointer if VLS is null. */
+static struct val_lab *
+val_labs_lookup__ (const struct val_labs *vls, const union value *value,
+                   unsigned int hash)
+{
+  struct val_lab *label;
+
+  HMAP_FOR_EACH_WITH_HASH (label, struct val_lab, node, hash, &vls->labels)
+    if (value_equal (&label->value, value, vls->width))
+      return label;
+
+  return NULL;
+}
+
 /* Searches VLS for a value label for VALUE.  If successful,
    returns the value label; otherwise, returns a null pointer.
    Returns a null pointer if VLS is null. */
 struct val_lab *
 val_labs_lookup (const struct val_labs *vls, const union value *value)
 {
+  return (vls == NULL ? NULL
+          : val_labs_lookup__ (vls, value, value_hash (value, vls->width, 0)));
+}
+
+/* Searches VLS for a value label whose label is exactly LABEL.  If successful,
+   returns the corresponding value.  Otherwise, returns a null pointer.
+
+   Returns a null pointer if VLS is null.
+
+   This function is O(n) in the number of labels in VLS. */
+const union value *
+val_labs_find_value (const struct val_labs *vls, const char *label_)
+{
+  const union value *value = NULL;
+
   if (vls != NULL)
     {
-      struct val_lab *label;
-      HMAP_FOR_EACH_WITH_HASH (label, struct val_lab, node,
-                               value_hash (value, vls->width, 0), &vls->labels)
-        if (value_equal (&label->value, value, vls->width))
-          return label;
+      const struct val_lab *vl;
+      const char *label;
+
+      label = intern_new (label_);
+      HMAP_FOR_EACH (vl, struct val_lab, node, &vls->labels)
+        if (vl->label == label)
+          {
+            value = &vl->value;
+            break;
+          }
+      intern_unref (label);
     }
-  return NULL;
+
+  return value;
 }
 \f
 /* Returns the first value label in VLS, in arbitrary order, or a
@@ -301,3 +339,45 @@ val_labs_sorted (const struct val_labs *vls)
   else
     return NULL;
 }
+
+/* Returns a hash value that represents all of the labels in VLS, starting from
+   BASIS. */
+unsigned int
+val_labs_hash (const struct val_labs *vls, unsigned int basis)
+{
+  const struct val_lab *label;
+  unsigned int hash;
+
+  hash = hash_int (val_labs_count (vls), basis);
+  HMAP_FOR_EACH (label, struct val_lab, node, &vls->labels)
+    hash ^= value_hash (&label->value, vls->width,
+                        hash_string (label->label, basis));
+  return hash;
+}
+
+/* Returns true if A and B contain the same values with the same labels,
+   false if they differ in some way. */
+bool
+val_labs_equal (const struct val_labs *a, const struct val_labs *b)
+{
+  const struct val_lab *label;
+
+  if (val_labs_count (a) != val_labs_count (b))
+    return false;
+  
+  if (a == NULL || b == NULL)
+    return true;
+
+  if (a->width != b->width)
+    return false;
+
+  HMAP_FOR_EACH (label, struct val_lab, node, &a->labels)
+    {
+      struct val_lab *label2 = val_labs_lookup__ (b, &label->value,
+                                                  label->node.hash);
+      if (!label2 || label->label != label2->label)
+        return false;
+    }
+
+  return true;
+}