This procedure marks range of readed messages as unread.
This is a test, can be compiled anywhere in the newsrc.c:

Newsrc N;
Range R;
N.group_low = 1;
N.group_high = 10;
N.read = g_array_new( FALSE, FALSE, sizeof(Range)); 
R.low = 1;
R.high = 4;
g_array_append_val (N.read, R);
R.low = 7;
R.high = 9;
g_array_append_val (N.read, R);
/ * Now the ranges are 1-4, 7-9
R.low = 3;
R.high = 4;
mark_range_unread ( &N, &R);
/* Now the ranges should be 1-2, 7-9
   but are 1-2, 5-4, 7-9  !! */

The procedure `mark_range_unread' checks if deleted interval
is inside another and in this case splits the another
interval, but the deleted interval can be also on the *edge*.
Here is a patch:

diff -cr pan-0.11.2.90-bug/pan/base/newsrc.c pan-0.11.2.90/pan/base/newsrc.c
*** pan-0.11.2.90-bug/pan/base/newsrc.c	Mon Dec  3 21:42:13 2001
--- pan-0.11.2.90/pan/base/newsrc.c	Sun Apr  7 00:58:06 2002
***************
*** 327,342 ****
  	
	g_array_remove_index (a, i);
  	
	--high_index;
  		}
! 		else if (range_contains (r, ur)) /* split */
  		{
! 	
	Range range;
! 	
	range.high = r->high;
! 	
	r->high = ur->low-1;
! 	
	range.low = ur->high+1;
! 	
	retval += ur->high+1-ur->low;
! 	
	g_array_insert_val (a, low_index+1, range);
! 	
	++high_index;
! 	
	i += 2;
  		}
  		else if (range_contains_point (r, ur->low)) /* change high */
  		{
--- 327,355 ----
  	
	g_array_remove_index (a, i);
  	
	--high_index;
  		}
! 		else if (range_contains (r, ur)) /* split or cut */
  		{
! 	
	if ( r->low == ur->low ) /* cut low */
! 	
	{
! 	
		r->low = ur->high+1;
! 	
		retval += ur->high+1-ur->low;
! 	
	}
! 	
	else if ( r->high == ur->high ) /* cut high */
! 	
	{
! 	
		r->high = ur->low-1;
! 	
		retval += ur->high+1-ur->low;
! 	
	} 
! 	
	else
! 	
	{ 
! 	
	        Range range; /* Split */
! 	
		range.high = r->high;
! 	
		r->high = ur->low-1;
! 	
		range.low = ur->high+1;
! 	
		retval += ur->high+1-ur->low;
! 	
		g_array_insert_val (a, low_index+1, range);
! 	
		++high_index;
! 	
		i += 2;
! 	
	}
  		}
  		else if (range_contains_point (r, ur->low)) /* change high */
  		{


Here is a patch for newsrc.c, which checks the 
ranges on both ends of procedures
`mark_range_unread' and `mark_range_read' and prints
complete information if something is incorrect.
I have used it for debugging:

diff -cr pan-0.11.2.90-dbg/pan/base/newsrc.c pan-0.11.2.90/pan/base/newsrc.c
*** pan-0.11.2.90-dbg/pan/base/newsrc.c	Sun Apr  7 01:26:52 2002
--- pan-0.11.2.90/pan/base/newsrc.c	Sun Apr  7 01:20:25 2002
***************
*** 216,227 ****
--- 216,263 ----
  	return merged;
  }
  
+ int check_range(Newsrc *n, const char *message)
+ {
+ 	Range *r1, *r2; guint i;
+ 	if (n->read->len < 2 ) return 0;
+ 	for ( i=1; i< n->read->len; i++ ) {
+ 		r1 = &g_array_index (n->read, Range, i-1);
+ 		r2 = &g_array_index (n->read, Range, i  );
+ 		if ( r1->low> r1->high) {
+ 	
	printf("%s r1.low>r1.high: %lu-%lu\n", message, r1->low, r1->high);
+ 	
	return 1;
+ 		}
+ 		if ( r2->low > r2->high) {
+ 	
	printf("%s r2.low>r2.high: %lu-%lu\n", message, r2->low, r2->high);
+ 	
	return 1;
+ 		}
+ 		if ( r1->high >= r2->low) {
+ 	
	printf("%s r1.high >= r2.low: %lu-%lu\n", message, r1->low, r2->high);
+ 	
	return 1;
+ 		}
+ 	}
+ 	return 0;
+ }
+ 
+ static void print_range(const GArray* rr)
+ {
+ 	guint i; Range *r;
+ 	printf("*** Begin\n");
+ 	for ( i=0; i < rr->len; i++ ) {
+ 		r = &g_array_index (rr, Range, i);
+ 		printf( "%lu-%lu ", r->low, r->high);
+ 	}
+ 	printf( "*** End\n");
+ }
+ 
  /**
   * @return the number of articles newly-marked as read 
   */
  static gulong
  mark_range_read (Newsrc * n, Range * rr)
  {
+         GArray *ranges_before = g_array_new( FALSE, FALSE, sizeof(Range));
+ 
  	GArray * a = n->read;
  	gint i;
  	gint low_index = 0;
***************
*** 229,234 ****
--- 265,273 ----
  	gulong retval = 0;
  	gboolean range_found = FALSE;
  
+         g_array_append_vals( ranges_before, n->read->data, n->read->len);
+         check_range( n, "mark_read - before" );
+ 
  	low_index = lower_bound (&rr->low,
  	                         a->data,
  	                         a->len,
***************
*** 290,301 ****
--- 329,350 ----
  		maybe_merge_ranges (a, low_index-1);
  	}
  
+         if (check_range( n, "mark_read - after" )) {
+               printf( "Inserted range: %lu-%lu", rr->low, rr->high); 
+ 		printf( "Error in check range\nRanges before:\n");
+ 		print_range(ranges_before);
+ 		printf( "Ranges after\n");
+ 		print_range(n->read);
+ 	}
+         g_array_free(ranges_before, FALSE);
  	return retval;
  }
  
  static gulong
  mark_range_unread (Newsrc * n, const Range * ur)
  {
+         GArray *ranges_before = g_array_new( FALSE, FALSE, sizeof(Range));
+ 
  	gint i;
  	gint low_index = -1;
  	gint high_index = -1;
***************
*** 304,309 ****
--- 353,361 ----
  	gulong retval = 0;
  	GArray * a = n->read;
  
+         g_array_append_vals( ranges_before, n->read->data, n->read->len);
+         check_range( n, "mark_unread - before" );
+ 
  	low_index = lower_bound (&ur->low,
  	                         a->data,
  	                         a->len,
***************
*** 366,371 ****
--- 418,431 ----
  		else ++i;
  	}
  
+         if (check_range( n, "mark_unread - after" )) {
+               printf( "Removed range: %lu-%lu", ur->low, ur->high); 
+ 		printf( "Error in check range\nRanges before:\n");
+ 		print_range(ranges_before);
+ 		printf( "Ranges after\n");
+ 		print_range(n->read);
+ 	}
+         g_array_free(ranges_before, FALSE);
  	return retval;
  }


Jiri Kubicek