Re: Performance patch, dir.c:do_reload_dir() on large dirs.

[Björn Eriksson]

On Thu, Dec 06, 2001 at 09:47:33PM -0500, Pavel Roskin wrote:
> >  A hash-table would make it 'less big O', scale and more predictable.
> > <...looking at code...> But perhaps not a binary search (see dir.c:658)
> > since the list isn't sorted?
> 
> Correct.  I'm fixing it.

 You're ever so cryptic pavel... Anyways, please have a look at the
attached (inline) patch:

Index: ChangeLog
===================================================================
RCS file: /cvs/gnome/mc/src/ChangeLog,v
retrieving revision 1.669
diff -u -p -r1.669 ChangeLog
--- ChangeLog   2001/12/03 23:38:12     1.669
+++ ChangeLog   2001/12/09 23:14:49
@@ -1,3 +1,8 @@
+2001-12-10  Pavel Roskin  <[EMAIL PROTECTED]>
+
+       * dir.c (do_reload_dir): Hash-table added.
+       From Björn Eriksson <[EMAIL PROTECTED]>
+
 2001-12-03  Pavel Roskin  <[EMAIL PROTECTED]>
 
        * dir.c (do_reload_dir): Optimize the logic - count the marks
Index: dir.c
===================================================================
RCS file: /cvs/gnome/mc/src/dir.c,v
retrieving revision 1.32
diff -u -p -r1.32 dir.c
--- dir.c       2001/12/07 02:47:04     1.32
+++ dir.c       2001/12/09 23:10:24
@@ -601,9 +601,9 @@ do_reload_dir (dir_list * list, sortfn *
     int next_free = 0;
     int i, status, link_to_dir, stalled_link;
     struct stat buf;
-    int tmp_len;               /* For optimisation */
     int dotdot_found = 0;
     int marked_cnt;
+    GHashTable *marked_files = g_hash_table_new(g_str_hash, g_str_equal);
 
     tree_store_start_check_cwd ();
     dirp = mc_opendir (".");
@@ -622,8 +622,10 @@ do_reload_dir (dir_list * list, sortfn *
            list->list[i].f.dir_size_computed;
        dir_copy.list[i].f.link_to_dir = list->list[i].f.link_to_dir;
        dir_copy.list[i].f.stalled_link = list->list[i].f.stalled_link;
-       if (list->list[i].f.marked)
+       if (list->list[i].f.marked) {
+            g_hash_table_insert(marked_files, dir_copy.list[i].fname, 
+&dir_copy.list[i]);
            marked_cnt++;
+        }
     }
 
     for (dp = mc_readdir (dirp); dp; dp = mc_readdir (dirp)) {
@@ -649,29 +651,23 @@ do_reload_dir (dir_list * list, sortfn *
        }
 
        list->list[next_free].f.marked = 0;
-       tmp_len = NLENGTH (dp);
 
        /*
         * If we have marked files in the copy, scan through the copy
         * to find matching file.  Decrease number of remaining marks if
         * we copied one.
-        * TODO: Use hash table.
         */
        if (marked_cnt > 0) {
-           for (i = 0; i < count; i++) {
-               if (tmp_len == dir_copy.list[i].fnamelen
-                   && !strcmp (dp->d_name, dir_copy.list[i].fname)) {
-                   list->list[next_free].f.marked =
-                       dir_copy.list[i].f.marked;
-                   if (dir_copy.list[i].f.marked) {
-                       marked_cnt--;
-                   }
-                   break;
-               }
-           }
+            file_entry *p;
+            if (NULL != (p = g_hash_table_lookup(marked_files, dp->d_name))) {
+                if (p->f.marked) {
+                    list->list[next_free].f.marked = 1;
+                    marked_cnt--;
+                }
+            }
        }
 
-       list->list[next_free].fnamelen = tmp_len;
+       list->list[next_free].fnamelen = NLENGTH (dp);
        list->list[next_free].fname = g_strdup (dp->d_name);
        list->list[next_free].f.link_to_dir = link_to_dir;
        list->list[next_free].f.stalled_link = stalled_link;
@@ -685,6 +681,7 @@ do_reload_dir (dir_list * list, sortfn *
     }
     mc_closedir (dirp);
     tree_store_end_check ();
+    g_hash_table_destroy(marked_files);
     if (next_free) {
        if (!dotdot_found)
            add_dotdot_to_list (list, next_free++);


-- 
//Björnen

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