small backstack fix

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@244 a592a061-630c-0410-9148-cb99ea01b6c8

ChangeLog

@@ -1,3 +1,11 @@
+1999-10-25  Lars Gullik Bjønnes  <larsbj@lyx.org>
+
+	* src/BufferView.C (restorePosition): don't do anything if the
+	backstack is empty.
+
+	* src/BackStack.h: added member empty, use this to test if there
+	is anything to pop...
+
 1999-10-25  Juergen Vigna  <jug@sad.it>
 
 	* forms/form1.fd +

src/BackStack.h

@@ -1,15 +1,15 @@
 // -*- C++ -*-
 /* This file is part of
-* ======================================================
-* 
-*           LyX, The Document Processor
-* 	 
-*	    Copyright (C) 1997-1998 The LyX Team.
-*
-*======================================================*/
+ * ======================================================
+ * 
+ *           LyX, The Document Processor
+ * 	 
+ *	    Copyright (C) 1997-1999 The LyX Team.
+ *
+ * ======================================================*/
 
-#ifndef _BACK_STACK_H
-#define _BACK_STACK_H
+#ifndef BACK_STACK_H
+#define BACK_STACK_H
 
 #include "LString.h"
 
@@ -30,29 +30,30 @@ public:
 		/// Cursor x-position
 		int x;
 		/// Cursor y-position
-		int y;   
+		int y;
 	};
 	///
-	BackStack(int n) : imax(n) {
-		item = new BackStackItem[imax];
-		i = 0;
-	}
+	BackStack(int n) : item(new BackStackItem[n]) , imax(n), i(0) {}
 	///
 	~BackStack() {
 		delete[] item;
 	}
 	///
 	void push(string f, int x, int y) {
-		if (i<imax) 
+		if (i < imax) 
 			item[i++].set(f, x, y);
 	}
 	///
-	string &pop(int *x, int *y) {
-		if (i>0) i--;
+	string & pop(int *x, int *y) {
+		if (i > 0) i--;
 		*x = item[i].x;
 		*y = item[i].y;
 		return item[i].fname;
 	}
+	///
+	bool empty() const {
+		return i == 0;
+	}
 private:
 	///
 	BackStackItem *item;

src/BufferView.C

@@ -1514,6 +1514,8 @@ void BufferView::savePosition()
 
 void BufferView::restorePosition()
 {
+	if (backstack->empty()) return;
+	
 	int  x, y;
 	string fname = backstack->pop(&x, &y);