[gnumeric] utils: new function for ordered hash traversal.

[Morten Welinder <mortenw src gnome org>]

commit b18c07f95919ea94d2f3adc004254f7b7ece20d0
Author: Morten Welinder <terra gnome org>
Date:   Tue May 20 19:18:03 2014 -0400

    utils: new function for ordered hash traversal.

 ChangeLog    |    4 +++-
 src/gutils.c |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/gutils.h |    9 +++++++++
 3 files changed, 65 insertions(+), 1 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 2de2aa5..4a4c23a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 2014-05-20  Morten Welinder  <terra gnome org>
 
+       * src/gutils.c (gnm_hash_table_foreach_ordered): New function.
+
        * src/gnm-so-filled.c (gnm_so_filled_write_xml_sax): Don't write
        outline and fill colours that are auto, even for the 1.0 format.
 
@@ -1355,7 +1357,7 @@
 2013-04-04  Jean Brefort  <jean brefort normalesup org>
 
        * src/graph.c (gnm_go_data_vector_load_len): correctly evaluate array
-       fucntions used as vectors. [697281]
+       functions used as vectors. [697281]
 
 2013-04-04  Jean Brefort  <jean brefort normalesup org>
 
diff --git a/src/gutils.c b/src/gutils.c
index 7109a39..d857977 100644
--- a/src/gutils.c
+++ b/src/gutils.c
@@ -742,3 +742,56 @@ gnm_float_hash (gnm_float const *d)
 
 /* ------------------------------------------------------------------------- */
 
+struct cb_compare {
+       GnmHashTableOrder order;
+       gpointer user;
+};
+
+static gint
+cb_compare (gconstpointer a_, gconstpointer b_, gpointer user_data)
+{
+       struct cb_compare *user = user_data;
+       gpointer *a = (gpointer )a_;
+       gpointer *b = (gpointer )b_;
+
+       return user->order (a[0], a[1], b[0], b[1], user->user);
+}
+
+
+void
+gnm_hash_table_foreach_ordered (GHashTable *h,
+                               GHFunc callback,
+                               GnmHashTableOrder order,
+                               gpointer user)
+{
+       unsigned ui;
+       GPtrArray *data;
+       struct cb_compare u;
+       GHashTableIter hiter;
+       gpointer key, value;
+
+       /* Gather all key-value pairs */
+       data = g_ptr_array_new ();
+       g_hash_table_iter_init (&hiter, h);
+       while (g_hash_table_iter_next (&hiter, &key, &value)) {
+               g_ptr_array_add (data, key);
+               g_ptr_array_add (data, value);
+       }
+
+       /* Sort according to given ordering */
+       u.order = order;
+       u.user = user;
+       g_qsort_with_data (data->pdata,
+                          data->len / 2, 2 * sizeof (gpointer),
+                          cb_compare,
+                          &u);
+
+       /* Call user callback with all pairs */
+       for (ui = 0; ui < data->len; ui += 2)
+               callback (g_ptr_array_index (data, ui),
+                         g_ptr_array_index (data, ui + 1),
+                         user);
+
+       /* Clean up */
+       g_ptr_array_free (data, TRUE);
+}
diff --git a/src/gutils.h b/src/gutils.h
index e74e1b4..53755ef 100644
--- a/src/gutils.h
+++ b/src/gutils.h
@@ -52,6 +52,15 @@ gboolean   gnm_object_has_readable_prop (gconstpointer obj,
 gint gnm_float_equal (gnm_float const *a, const gnm_float *b);
 guint gnm_float_hash (gnm_float const *d);
 
+typedef int (*GnmHashTableOrder) (gpointer key_a, gpointer val_a,
+                                 gpointer key_b, gpointer val_b,
+                                 gpointer user);
+
+void gnm_hash_table_foreach_ordered (GHashTable *h,
+                                    GHFunc callback,
+                                    GnmHashTableOrder order,
+                                    gpointer user);
+
 G_END_DECLS
 
 #endif /* _GNM_GUTILS_H_ */