Sort attributes by name for display, to make order arch-independent.

[pspp] / src / data / attributes.c

diff --git a/src/data/attributes.c b/src/data/attributes.c
index d99e945b014def2836ec1eb57ea33631fc5086d4..d262e2ebc3a8438ab56404928361bd19b54eeb5b 100644 (file)
--- a/src/data/attributes.c
+++ b/src/data/attributes.c
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2008, 2009 Free Software Foundation, Inc.
+   Copyright (C) 2008, 2009, 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
@@ -16,12 +16,15 @@
 
 #include <config.h>
 
-#include <data/attributes.h>
+#include "data/attributes.h"
+
 #include <assert.h>
 #include <string.h>
-#include <libpspp/array.h>
-#include <libpspp/hash-functions.h>
-#include "xalloc.h"
+
+#include "libpspp/array.h"
+#include "libpspp/hash-functions.h"
+
+#include "gl/xalloc.h"
 
 /* A custom attribute of the sort maintained by the DATAFILE
    ATTRIBUTE and VARIABLE ATTRIBUTE commands.
@@ -296,3 +299,38 @@ attrset_next (const struct attrset *set, struct attrset_iterator *iterator)
   iterator->node = hmap_next (&set->map, iterator->node);
   return iterator_data (iterator);
 }
+
+static int
+compare_attribute_by_name (const void *a_, const void *b_)
+{
+  const struct attribute *const *a = a_;
+  const struct attribute *const *b = b_;
+
+  return strcmp ((*a)->name, (*b)->name);
+}
+
+/* Allocates and returns an array of pointers to attributes
+   that is sorted by attribute name.  The array has
+   'attrset_count (SET)' elements.  The caller is responsible for
+   freeing the array. */
+struct attribute **
+attrset_sorted (const struct attrset *set)
+{
+  if (set != NULL && attrset_count (set) > 0)
+    {
+      struct attribute **attrs;
+      struct attribute *attr;
+      size_t i;
+
+      attrs = xmalloc (attrset_count (set) * sizeof *attrs);
+      i = 0;
+      HMAP_FOR_EACH (attr, struct attribute, node, &set->map)
+        attrs[i++] = attr;
+      assert (i == attrset_count (set));
+      qsort (attrs, attrset_count (set), sizeof *attrs,
+             compare_attribute_by_name);
+      return attrs;
+    }
+  else
+    return NULL;
+}