History stacks

botanjs/src/Components/Vim/State/History.js

@@ -0,0 +1,96 @@
+(function(){
+	var ns = __namespace( "Components.Vim.State" );
+
+	/** @type {System.Debug} */
+	var debug                        = __import( "System.Debug" );
+
+	// private static
+	var Zones = {};
+
+	var PartialBA = function( a, b )
+	{
+		var l = b.length;
+		if( a.length < l ) return false;
+
+		for( var i = 0; i < l; i ++ )
+		{
+			if( a[ i ] != b[ i ] ) return false;
+		}
+
+		return true;
+	};
+
+	var ExactAB = function( a, b )
+	{
+		var l = a.length < b.length ? b.length : a.length;
+		for( var i = 0; i < l; i ++ )
+		{
+			if( a[ i ] != b[ i ] ) return false;
+		}
+
+		return true;
+	}
+
+	var History = function( z )
+	{
+		if( !Zones[ z ] ) Zones[ z ] = [];
+
+		this.__pi = 0;
+		this.__zone = Zones[ z ];
+		this.reset();
+	};
+
+	History.prototype.push = function( stack )
+	{
+		if( this.__zone.length
+			&& ExactAB( this.__zone[ this.__zone.length - 1 ], stack )
+		) {
+			debug.Info( "This is the previous command, skipping" );
+			return;
+		}
+		this.__zone.push( stack );
+	};
+
+	History.prototype.prev = function( stack )
+	{
+		if( this.__zone.length <= this.__i ) this.reset();
+
+		while( -1 < this.__i )
+		{
+			var st = this.__zone[ this.__i -- ];
+			if( st && PartialBA( st, stack ) )
+			{
+				return st.slice();
+			}
+		}
+
+		return null;
+	};
+
+	History.prototype.next = function( stack )
+	{
+		if( this.__i < 0 )
+		{
+			this.__i ++;
+			this.next( stack );
+		}
+
+		while( this.__i < this.__zone.length )
+		{
+			var st = this.__zone[ this.__i ++ ];
+			if( st && PartialBA( st, stack ) )
+			{
+				return st.slice();
+			}
+		}
+
+		return null;
+	};
+
+	History.prototype.reset =  function()
+	{
+		this.__i = this.__zone.length - 1;
+	};
+
+	ns[ NS_EXPORT ]( EX_CLASS, "History", History );
+})();