From 7902803063ad9b5de29d46ed8188bbcff48df969 Mon Sep 17 00:00:00 2001
From: Tom Payne <twpayne@gmail.com>
Date: Wed, 25 Jul 2012 17:39:38 +0200
Subject: [PATCH] Add ol.TileCoord.toQuadKey and createFromQuadKey

---
 src/ol/tile/tilecoord.js      | 60 +++++++++++++++++++++++++++++++++++
 src/ol/tile/tilecoord_test.js | 13 ++++++++
 2 files changed, 73 insertions(+)

diff --git a/src/ol/tile/tilecoord.js b/src/ol/tile/tilecoord.js
index 693fa8b870..63431965df 100644
--- a/src/ol/tile/tilecoord.js
+++ b/src/ol/tile/tilecoord.js
@@ -4,6 +4,17 @@ goog.require('goog.array');
 goog.require('ol.Coordinate');
 
 
+/**
+ * @enum {number}
+ */
+ol.QuadKeyCharCode = {
+  ZERO: '0'.charCodeAt(0),
+  ONE: '1'.charCodeAt(0),
+  TWO: '2'.charCodeAt(0),
+  THREE: '3'.charCodeAt(0)
+};
+
+
 
 /**
  * @constructor
@@ -25,6 +36,33 @@ ol.TileCoord = function(z, x, y) {
 goog.inherits(ol.TileCoord, ol.Coordinate);
 
 
+/**
+ * @param {string} quadKey Quad key.
+ * @return {ol.TileCoord} Tile coordinate.
+ */
+ol.TileCoord.createFromQuadKey = function(quadKey) {
+  var z = quadKey.length, x = 0, y = 0;
+  var mask = 1 << (z - 1);
+  var i;
+  for (i = 0; i < z; ++i) {
+    switch (quadKey.charCodeAt(i)) {
+      case ol.QuadKeyCharCode.ONE:
+        x += mask;
+        break;
+      case ol.QuadKeyCharCode.TWO:
+        y += mask;
+        break;
+      case ol.QuadKeyCharCode.THREE:
+        x += mask;
+        y += mask;
+        break;
+    }
+    mask >>= 1;
+  }
+  return new ol.TileCoord(z, x, y);
+};
+
+
 /**
  * @return {ol.TileCoord} Clone.
  */
@@ -41,6 +79,28 @@ ol.TileCoord.prototype.hash = function() {
 };
 
 
+/**
+ * @return {string} Quad key.
+ */
+ol.TileCoord.prototype.toQuadKey = function() {
+  var digits = new Array(this.z);
+  var mask = 1 << (this.z - 1);
+  var i, charCode;
+  for (i = 0; i < this.z; ++i) {
+    charCode = ol.QuadKeyCharCode.ZERO;
+    if (this.x & mask) {
+      charCode += 1;
+    }
+    if (this.y & mask) {
+      charCode += 2;
+    }
+    digits[i] = String.fromCharCode(charCode);
+    mask >>= 1;
+  }
+  return digits.join('');
+};
+
+
 /**
  * @return {string} String.
  */
diff --git a/src/ol/tile/tilecoord_test.js b/src/ol/tile/tilecoord_test.js
index b106a60a81..815e90a90c 100644
--- a/src/ol/tile/tilecoord_test.js
+++ b/src/ol/tile/tilecoord_test.js
@@ -2,6 +2,14 @@ goog.require('goog.testing.jsunit');
 goog.require('ol.TileCoord');
 
 
+function testCreateFromQuadKey() {
+  var tileCoord = ol.TileCoord.createFromQuadKey('213');
+  assertEquals(3, tileCoord.z);
+  assertEquals(3, tileCoord.x);
+  assertEquals(5, tileCoord.y);
+}
+
+
 function testConstructorOrderZXY() {
   var tc1 = new ol.TileCoord(1, 2, 3);
   assertEquals(1, tc1.z);
@@ -24,3 +32,8 @@ function testFromString() {
   assertEquals(2, tc.x);
   assertEquals(3, tc.y);
 }
+
+
+function testToQuadKey() {
+  assertEquals('213', (new ol.TileCoord(3, 3, 5)).toQuadKey());
+}