Added basic ol.parser.polyline module

This module will contain the low-level functions for Google's "Encoded
Polyline" algorithm.

src/ol/parser/polyline.js

@@ -0,0 +1,35 @@
+goog.provide('ol.parser.polyline');
+
+
+/**
+ * Encode one single signed integer and return an encoded string
+ *
+ * @param {number} num Signed integer that should be encoded.
+ * @return {string} The encoded string.
+ */
+ol.parser.polyline.encodeSignedInteger = function(num) {
+  var sgn_num = num << 1;
+  if (num < 0)
+    sgn_num = ~(sgn_num);
+
+  return ol.parser.polyline.encodeUnsignedInteger(sgn_num);
+};
+
+
+/**
+ * Encode one single unsigned integer and return an encoded string
+ *
+ * @param {number} num Unsigned integer that should be encoded.
+ * @return {string} The encoded string.
+ */
+ol.parser.polyline.encodeUnsignedInteger = function(num) {
+  var value, encodeString = '';
+  while (num >= 0x20) {
+    value = (0x20 | (num & 0x1f)) + 63;
+    encodeString += (String.fromCharCode(value));
+    num >>= 5;
+  }
+  value = num + 63;
+  encodeString += (String.fromCharCode(value));
+  return encodeString;
+};