Don't go into an infinite loop when trying to convert positions with w idth of...

Don't go into an infinite loop when trying to convert positions with w idth of 0. Hopefully fixes issue 6005

sources/LineBlock.m

@@ -1338,8 +1338,10 @@ static int Search(NSString* needle,
 - (BOOL)convertPosition:(int)position
               withWidth:(int)width
                     toX:(int*)x
-                    toY:(int*)y
-{
+                    toY:(int*)y {
+    if (width <= 0) {
+        return NO;
+    }
     int i;
     *x = 0;
     *y = 0;

sources/LineBuffer.m

@@ -764,8 +764,10 @@ static int RawNumLines(LineBuffer* buffer, int width) {
 }
 // Returns an array of XRange values
-- (NSArray*)convertPositions:(NSArray*)resultRanges withWidth:(int)width
-{
+- (NSArray*)convertPositions:(NSArray*)resultRanges withWidth:(int)width {
+    if (width <= 0) {
+        return nil;
+    }
     // Create sorted array of all positions to convert.
     NSMutableArray* unsortedPositions = [NSMutableArray arrayWithCapacity:[resultRanges count] * 2];
     for (ResultRange* rr in resultRanges) {