[gconf] Avoid O(n^2) overhead in attribute lookup and speed up whitespace handling

[Matthias Clasen <matthiasc src gnome org>]

commit c7cd2c38407d49aa289eb16387c399def9bbcfb4
Author: Michael Meeks <michael meeks novell com>
Date:   Sat Apr 25 02:57:28 2009 -0400

    Avoid O(n^2) overhead in attribute lookup and speed up whitespace handling
---
 backends/markup-tree.c |   44 ++++++++++++++++----------------------------
 1 files changed, 16 insertions(+), 28 deletions(-)

diff --git a/backends/markup-tree.c b/backends/markup-tree.c
index 0f9bb89..d2f5c16 100644
--- a/backends/markup-tree.c
+++ b/backends/markup-tree.c
@@ -2167,51 +2167,40 @@ locate_attributes (GMarkupParseContext *context,
 
   retval = TRUE;
 
-  i = 0;
-  while (attribute_names[i])
+  for (i = 0; attribute_names[i]; i++)
     {
       int j;
-      gboolean found;
 
-      found = FALSE;
-      j = 0;
-      while (j < n_attrs)
+      for (j = 0; j < n_attrs; j++)
         {
+	  /* already matched */
+	  if (attrs[j].name == NULL)
+	    continue;
+
           if (strcmp (attrs[j].name, attribute_names[i]) == 0)
             {
               retloc = attrs[j].retloc;
+	      attrs[j].name = NULL;
 
-              if (*retloc != NULL)
-                {
-                  set_error (error, context,
-                             GCONF_ERROR_PARSE_ERROR,
-                             _("Attribute \"%s\" repeated twice on the same <%s> element"),
-                             attrs[j].name, element_name);
-                  retval = FALSE;
-                  goto out;
-                }
+	      /* if this fails we passed the same retloc twice */
+	      g_assert (*retloc == NULL);
 
               *retloc = attribute_values[i];
-              found = TRUE;
+	      break;
             }
-
-          ++j;
         }
 
-      if (!found)
+      if (j >= n_attrs)
         {
           set_error (error, context,
                      GCONF_ERROR_PARSE_ERROR,
-                     _("Attribute \"%s\" is invalid on <%s> element in this context"),
+                     _("Attribute \"%s\" is invalid, or duplicated on <%s> element in this context"),
                      attribute_names[i], element_name);
           retval = FALSE;
-          goto out;
+	  break;
         }
-      
-      ++i;
     }
 
- out:
   return retval;
 }
 
@@ -3494,10 +3483,9 @@ all_whitespace (const char *text,
 
   while (p != end)
     {
-      if (!g_ascii_isspace (*p))
-        return FALSE;
-
-      p = g_utf8_next_char (p);
+      if (G_UNLIKELY (*p != ' ' && *p != '\t' && *p != '\n' && *p != '\r'))
+	return FALSE;
+      p++;
     }
 
   return TRUE;