Implement naive en/decoder + add link to share game

index.html

@@ -28,7 +28,10 @@
 			</ul>
 			<button id="load">Load</button>
 			<table id="grid"></table>
+			<div id="export">
 				<button id="save">Save</button>
+				<a id="share">Share this grid</a>
+			</div>
 		</div>
 	</body>
 </html>

js/Mode/Edit.js

@@ -3,12 +3,14 @@ import Grid;
 import Grid.Color;
 import Mode;
 import Toolbox;
+import Share;
 
 var down = false;
 Grid.get().element.addEventListener('mouseleave', function() {
 	down = false;
 });
 var save = document.getElementById('save');
+var share = document.getElementById('share')
 
 return {
 	events: {
@@ -64,5 +66,6 @@ function colorCell(row, column) {
 function checkCompleteness() {
 	if(Grid.get().missing.isEmpty()) {
 		Mode.setEnabled(true, ['play', 'solve']);
+		share.href = '?game=' + Share.naiveEncode(Grid.get().data);
 	}
 }

js/Share.js

@@ -1,78 +1,24 @@
+import * as Decoder from Share.Decoder;
+import * as Encoder from Share.Encoder;
+import {iter, square} from Grid.Util;
+
 return {
 	compress: compress,
 	naive: naive
 }
 
 function compress(grid) {
-	var state = {
-		data: '',
-		stack: 0,
-		size: 0
-	};
-	var color;
-	var count;
-	for(var i = 0; i < grid.length; i++) {
-		for(var j = 0; j < grid.length; j++) {
-			if(color == undefined) {
-				color = grid[i][j];
-			} else if(grid[i][j] != color) {
-			} else if(count > 6) {
-			} else {
-				count++;
-			}
-		}
-	}
-	return atob(compressed);
 }
 
-function appendLength(state, n) {
-	append(state, 1);
-	for(var i = 0; i < 3; i++) {
-		append(state, n % 2);
-		n >>= 1;
-	}
+function naiveEncode(grid) {
+	var encoder = Encoder.make();
+	iter(grid, function(row, column) {
+		encoder.int(3)(grid[row][column]);
+	});
+	return encoder.output();
 }
 
-function appendColor(state, c) {
-	append(state, 0);
-	for(var i = 0; i < 3; i++) {
-		append(state, c % 2);
-		c >>= 1;
-	}
-}
-
-function appendColorNaive(state, c) {
-	for(var i = 0; i < 3; i++) {
-		append(state, c % 2);
-		c >>= 1;
-	}
-}
-
-function append(state, one) {
-	if(state.size > 7) {
-		flush(state);
-	}
-	state.stack = 2*state.stack + (one ? 1 : 0);
-	state.size++;
-}
-
-function flush(state) {
-	state.data = state.data + String.fromCharCode(state.stack);
-	state.stack = 0;
-	state.size = 0;
-}
-
-function naive(grid) {
-	var state = {
-		data: '',
-		stack: 0,
-		size: 0
-	};
-	for(var i = 0; i < grid.length; i++) {
-		for(var j = 0; j < grid.length; j++) {
-			appendColorNaive(state, grid[i][j]);
-		}
-	}
-	flush(state);
-	return btoa(state.data);
+function naiveDecode(size, input) {
+	var decoder = Decoder.make(input);
+	return generate(size, size, function() {return decoder.int(3);});
 }

js/Share/Decoder.js

@@ -0,0 +1,49 @@
+function Decoder(input) {
+	this.input = atob(input);
+	this.cache = 0;
+	this.size = 0;
+}
+
+Decoder.prototype.pop = function() {
+	if(this.size < 1) {
+		if(this.input.length < 1) {
+			return null;
+		} else {
+			this.cache = this.input.charCodeAt(0);
+			this.size = 8;
+			this.input = this.input.slice(1);
+		}
+	}
+	this.size--;
+	var wasFirstBitOne = this.cache > 0x7f;
+	this.cache = (2*this.cache) & 0xff;
+	return wasFirstBitOne ? 1 : 0;
+};
+
+Decoder.prototype.variableLength3 = function() {
+	if(this.pop() == 1) {
+		return this.pop() + 1;
+	} else {
+		return 0;
+	}
+};
+
+Decoder.prototype.variableLength6 = function() {
+	if(this.pop() == 1) {
+		return 2 + this.int(2);
+	} else {
+		return this.pop();
+	}
+};
+
+Decoder.prototype.int = function(size) {
+	var result = 0;
+	for(var i = 0; i < size; i++) {
+		result = 2*result + this.pop();
+	}
+	return result;
+};
+
+return {
+	make: function(input) {return new Decoder(input);}
+};

js/Share/Encoder.js

@@ -0,0 +1,56 @@
+function Encoder() {
+	this.data = '';
+	this.stack = 0;
+	this.size = 0;
+}
+
+Encoder.prototype.push = function(one) {
+	if(this.size > 7) {
+		this.flush();
+	}
+	this.stack = 2*this.stack + (one ? 1 : 0);
+	this.size++;
+};
+
+Encoder.prototype.flush = function() {
+	this.data = this.data + String.fromCharCode(this.stack);
+	this.stack = 0;
+	this.size = 0;
+};
+
+Encoder.prototype.output = function() {
+	while(this.size < 8) {
+		this.push(0);
+	}
+	this.flush();
+	return btoa(this.data);
+};
+
+Encoder.prototype.variableLength3 = function(n) {
+	if(n > 0) {
+		this.push(1);
+	}
+	this.push(n > 1);
+};
+
+Encoder.prototype.variableLength6 = function(n) {
+	if(n > 1) {
+		this.push(1);
+	}
+	this.push(n > 3);
+	this.push(n % 2);
+};
+
+Encoder.prototype.int = function(size) {
+	var encoder = this;
+	return function(n) {
+		for(var i = 0; i < size; i++) {
+			encoder.push(n > 3);
+			n = (2*n) & 7;
+		}
+	}
+};
+
+return {
+	make: function() {return new Encoder();}
+};