(prot_a_output_text_mapping_reverse): New function.

src/server/prot-a-output.c

 /*
- * $Id: prot-a-output.c,v 0.69 2003/08/16 17:38:20 ceder Exp $
+ * $Id: prot-a-output.c,v 0.70 2003/08/22 06:44:57 ceder Exp $
  * Copyright (C) 1991-2002  Lysator Academic Computer Association.
  *
  * This file is part of the LysKOM server.
@@ -1076,7 +1076,7 @@ prot_a_output_text_mapping(Connection *fp,
     else
 	prot_a_output_ul(fp, limit);
 
-    /* Emit the "later-texts-exists" flag. */
+    /* Emit the "more-texts-exists" flag. */
 
     isc_puts(iter.search_ended ? " 0" : " 1", fp->isc_session);
 
@@ -1128,6 +1128,101 @@ prot_a_output_text_mapping(Connection *fp,
     }
 }
 
+void
+prot_a_output_text_mapping_reverse(Connection *fp,
+				   Text_mapping_reverse *map)
+{
+    Local_text_no lowest;
+    Local_text_no zeroes = 0;
+    Local_text_no nonzeroes = 0;
+    L2g_iterator iter;
+    L2g_reverse_iterator riter;
+
+    /* Initialize iterators to something. Otherwise some tools will flag
+       a read uninitialized memory in the for initializer. */
+
+    iter.l2g = NULL;
+    iter.binfo = NULL;
+    iter.arrindex = 0;
+    iter.beginval = 0;
+    iter.endval = 0;
+    iter.search_ended = 0;
+    iter.lno = 0;
+    iter.tno = 0;
+
+    riter.l2g = NULL;
+    riter.binfo = NULL;
+    riter.arrindex = 0;
+    riter.beginval = 0;
+    riter.endval = 0;
+    riter.search_ended = 0;
+    riter.lno = 0;
+    riter.tno = 0;
+    
+    /* Count the number of internal zeroes to determine if we should
+       use a dense or sparse representation. */
+
+    for (l2gi_searchsome_reverse(&riter, map->l2g, 0, map->ceiling),
+	     lowest = riter.search_ended ? map->ceiling : riter.lno + 1;
+	 !riter.search_ended && nonzeroes < map->no_of_texts;
+	 l2gi_prev(&riter))
+    {
+	zeroes += (lowest - riter.lno) - 1;
+	nonzeroes++;
+	lowest = riter.lno;
+    }
+
+    prot_a_output_ul(fp, lowest);
+    prot_a_output_ul(fp, map->ceiling);
+
+    /* Emit the "more-texts-exists" flag. */
+    isc_puts(riter.search_ended ? " 0" : " 1", fp->isc_session);
+
+    /* Emit the block, either a sparse or a dense one. */
+    if (nonzeroes == 0)
+    {
+	/* Special case: an empty array.  Use the sparse format so
+	   that we don't have to philosophize about what the lower
+	   limit in the text-list should be. */
+	isc_puts(" 0 0 *", fp->isc_session);
+    }
+    else if (zeroes >= nonzeroes)
+    {
+	/* There are at least as many zeroes as real mappings, so use
+	   a sparse representation. */
+
+	isc_puts(" 0", fp->isc_session);
+	prot_a_output_ul(fp, nonzeroes);
+	isc_puts(" {", fp->isc_session);
+
+	for (l2gi_searchsome(&iter, map->l2g, lowest, map->ceiling);
+	     !iter.search_ended;
+	     l2gi_next(&iter))
+	{
+	    prot_a_output_ul(fp, iter.lno);
+	    prot_a_output_ul(fp, iter.tno);
+	}
+	isc_puts(" }", fp->isc_session);
+    }
+    else
+    {
+	/* Emit a dense block. */
+	isc_puts(" 1", fp->isc_session);
+	prot_a_output_ul(fp, lowest);
+	prot_a_output_ul(fp, zeroes + nonzeroes);
+	isc_puts(" {", fp->isc_session);
+	for (l2gi_searchsome(&iter, map->l2g, lowest, map->ceiling);
+	     !iter.search_ended;
+	     l2gi_next(&iter))
+	{
+	    while (lowest++ < iter.lno)
+		isc_puts(" 0", fp->isc_session);
+	    prot_a_output_ul(fp, iter.tno);
+	}
+	isc_puts(" }", fp->isc_session);
+    }
+}
+
 void
 prot_a_output_stats_description(Connection *fp,
 				Stats_description *result)

src/server/prot-a-output.h

 /*
- * $Id: prot-a-output.h,v 0.35 2003/08/16 11:28:58 ceder Exp $
+ * $Id: prot-a-output.h,v 0.36 2003/08/22 06:44:57 ceder Exp $
  * Copyright (C) 1991-1992, 1994-1999, 2002  Lysator Academic Computer Association.
  *
  * This file is part of the LysKOM server.
@@ -23,7 +23,7 @@
  * Please report bugs at http://bugzilla.lysator.liu.se/. 
  */
 /*
- * $Id: prot-a-output.h,v 0.35 2003/08/16 11:28:58 ceder Exp $
+ * $Id: prot-a-output.h,v 0.36 2003/08/22 06:44:57 ceder Exp $
  *
  */
 extern void
@@ -231,6 +231,10 @@ void
 prot_a_output_text_mapping(Connection *fp,
 			   Text_mapping *result);
 
+void
+prot_a_output_text_mapping_reverse(Connection *fp,
+				   Text_mapping_reverse *map);
+
 void
 prot_a_output_stats_description(Connection *fp,
 				Stats_description *result);