Unify string list stripping functions and operate on list in place

There were two string list stripping functions, when the only difference
was to operate from the beginning or end of the list. Also, the function
was copying the list and operating on that unnecessarily.

1 files changed, 20 insertions, 37 deletions

diff --git a/pkg.c b/pkg.c
index a7c05a5..14a7e39 100644
--- a/pkg.c
+++ b/pkg.c
@@ -425,42 +425,15 @@ get_package_quiet (const char *name)
 }
 
 static GList *
-string_list_strip_duplicates (GList *list)
+string_list_strip_duplicates (GList *list, gboolean forward)
 {
   GHashTable *table;
   GList *tmp;
 
   table = g_hash_table_new (g_str_hash, g_str_equal);
-  for (tmp = list; tmp != NULL; tmp = g_list_next (tmp))
-    {
-        if (!g_hash_table_lookup_extended (table, tmp->data, NULL, NULL))
-        {
-          /* Unique string. Track it and and move to the next. */
-          g_hash_table_replace (table, tmp->data, tmp->data);
-        }
-      else
-        {
-          GList *dup = tmp;
-
-          /* Remove the duplicate string from the list. */
-          debug_spew (" removing duplicate \"%s\"\n", tmp->data);
-          tmp = tmp->prev;
-          list = g_list_remove_link (list, dup);
-        }
-    }
-  g_hash_table_destroy (table);
-
-  return list;
-}
-
-static GList *
-string_list_strip_duplicates_from_back (GList *list)
-{
-  GHashTable *table;
-  GList *tmp;
-  
-  table = g_hash_table_new (g_str_hash, g_str_equal);
-  for (tmp = g_list_last (list); tmp != NULL; tmp = g_list_previous (tmp))
+  for (tmp = forward ? list : g_list_last (list);
+       tmp != NULL;
+       tmp = forward ? g_list_next (tmp) : g_list_previous (tmp))
     {
       if (!g_hash_table_lookup_extended (table, tmp->data, NULL, NULL))
         {
@@ -471,14 +444,24 @@ string_list_strip_duplicates_from_back (GList *list)
         {
           GList *dup = tmp;
 
-          /* Remove the duplicate string from the list. */
-          debug_spew (" removing duplicate (from back) \"%s\"\n", tmp->data);
-          tmp = tmp->next;
+          /* Remove the duplicate string from the list and move to the last
+           * element to prepare for the next iteration. */
+          if (forward)
+            {
+              debug_spew (" removing duplicate \"%s\"\n", tmp->data);
+              tmp = g_list_previous (tmp);
+            }
+          else
+            {
+              debug_spew (" removing duplicate (from back) \"%s\"\n",
+                          tmp->data);
+              tmp = g_list_next (tmp);
+            }
           list = g_list_remove_link (list, dup);
         }
     }
   g_hash_table_destroy (table);
-  
+
   return list;
 }
 
@@ -1011,7 +994,7 @@ get_multi_merged (GList *pkgs, GetListFunc func, gboolean in_path_order,
   char *retval;
 
   list = fill_list (pkgs, func, in_path_order, include_private);
-  list = string_list_strip_duplicates (list);
+  list = string_list_strip_duplicates (list, TRUE);
   retval = string_list_to_string (list);
   g_list_free (list);
 
@@ -1026,7 +1009,7 @@ get_multi_merged_from_back (GList *pkgs, GetListFunc func,
   char *retval;
 
   list = fill_list (pkgs, func, in_path_order, include_private);
-  list = string_list_strip_duplicates_from_back (list);
+  list = string_list_strip_duplicates (list, FALSE);
   retval = string_list_to_string (list);
   g_list_free (list);