polyline: Added encode/decodeFloat() functions

src/ol/parser/polyline.js

@@ -1,6 +1,33 @@
 goog.provide('ol.parser.polyline');
 
 
+/**
+ * Encode one single floating point number and return an encoded string
+ *
+ * @param {number} num Floating point number that should be encoded.
+ * @param {number=} opt_factor The factor by which num will be multiplied.
+ * The remaining decimal places will get rounded away.
+ * @return {string} The encoded string.
+ */
+ol.parser.polyline.encodeFloat = function(num, opt_factor) {
+  num = Math.round(num * (opt_factor || 1e5));
+  return ol.parser.polyline.encodeSignedInteger(num);
+};
+
+
+/**
+ * Decode one single floating point number from an encoded string
+ *
+ * @param {string} encoded An encoded string.
+ * @param {number=} opt_factor The factor by which the result will be divided.
+ * @return {number} The decoded floating point number.
+ */
+ol.parser.polyline.decodeFloat = function(encoded, opt_factor) {
+  var result = ol.parser.polyline.decodeSignedInteger(encoded);
+  return result / (opt_factor || 1e5);
+};
+
+
 /**
  * Encode one single signed integer and return an encoded string
  *

test/spec/ol/parser/polyline.test.js

@@ -2,6 +2,46 @@ goog.provide('ol.test.parser.polyline');
 
 describe('ol.parser.polyline', function() {
 
+  describe('encodeFloat', function() {
+    it('returns expected value', function() {
+      var encodeFloat = ol.parser.polyline.encodeFloat;
+
+      expect(encodeFloat(0.00000)).toEqual('?');
+      expect(encodeFloat(-0.00001)).toEqual('@');
+      expect(encodeFloat(0.00001)).toEqual('A');
+      expect(encodeFloat(-0.00002)).toEqual('B');
+      expect(encodeFloat(0.00002)).toEqual('C');
+      expect(encodeFloat(0.00015)).toEqual(']');
+      expect(encodeFloat(-0.00016)).toEqual('^');
+
+      expect(encodeFloat(-0.1, 10)).toEqual('@');
+      expect(encodeFloat(0.1, 10)).toEqual('A');
+
+      expect(encodeFloat(16 * 32 / 1e5)).toEqual('__@');
+      expect(encodeFloat(16 * 32 * 32 / 1e5)).toEqual('___@');
+    });
+  });
+
+  describe('decodeFloat', function() {
+    it('returns expected value', function() {
+      var decodeFloat = ol.parser.polyline.decodeFloat;
+
+      expect(decodeFloat('?')).toEqual(0.00000);
+      expect(decodeFloat('@')).toEqual(-0.00001);
+      expect(decodeFloat('A')).toEqual(0.00001);
+      expect(decodeFloat('B')).toEqual(-0.00002);
+      expect(decodeFloat('C')).toEqual(0.00002);
+      expect(decodeFloat(']')).toEqual(0.00015);
+      expect(decodeFloat('^')).toEqual(-0.00016);
+
+      expect(decodeFloat('@', 10)).toEqual(-0.1);
+      expect(decodeFloat('A', 10)).toEqual(0.1);
+
+      expect(decodeFloat('__@')).toEqual(16 * 32 / 1e5);
+      expect(decodeFloat('___@')).toEqual(16 * 32 * 32 / 1e5);
+    });
+  });
+
   describe('encodeSignedInteger', function() {
     it('returns expected value', function() {
       var encodeSignedInteger = ol.parser.polyline.encodeSignedInteger;