Add parser for OGC Filter 1.0 and 1.1 (read/write)

This work is based on the ol.expr package by @tschaub.
It adds a few named expression functions to that package:

 * INTERSECTS, CONTAINS, DWITHIN, WITHIN (no client-side implementation as yet)
 * LIKE (like comparison with wildcard, singleChar and escapeChar)
 * IEQ (case-insensitive equality)
 * INEQ (case-insensitive non-equality)

It also adds a few extra parameters to the existing EXTENT function to be able
to deserialize and serialize all info (i.e. projection and property name).

Some changes were needed for the GML parser as well:

 * createGeometry function needed to be public
 * when parsing Box (GML2) and Envelope (GML3) also parse the srsName
 * fix up writing for Box and Envelope now that bounds is an array

Also added createDocumentFragment function to the XML parser. Implementation
is similar to OpenLayers 2.

Some addtional notes on the implementation:

 * PropertyIsBetween was implemented as an ol.expr.Logical with operator
   ol.expr.LogicalOp.AND and two ol.expr.Comparison instances with operator
   ol.expr.ComparisonOp.GTE and ol.expr.ComparisonOp.LTE
 * In OGC Filter And and Or can contain more than 2 sub filters, so this
   is translated into a hierarchy of ol.expr.Logical

src/ol/expr/expression.js

@@ -97,7 +97,14 @@ ol.expr.lib = {};
 ol.expr.functions = {
   EXTENT: 'extent',
   FID: 'fid',
-  GEOMETRY_TYPE: 'geometryType'
+  GEOMETRY_TYPE: 'geometryType',
+  INTERSECTS: 'intersects',
+  CONTAINS: 'contains',
+  DWITHIN: 'dwithin',
+  WITHIN: 'within',
+  LIKE: 'like',
+  IEQ: 'ieq',
+  INEQ: 'ineq'
 };
 
 
@@ -107,12 +114,16 @@ ol.expr.functions = {
  * @param {number} maxX Maximum x-coordinate value.
  * @param {number} minY Minimum y-coordinate value.
  * @param {number} maxY Maximum y-coordinate value.
+ * @param {string=} opt_projection Projection of the extent.
+ * @param {string=} opt_attribute Name of the geometry attribute to use.
  * @return {boolean} The provided extent intersects the feature's extent.
  * @this {ol.Feature}
  */
-ol.expr.lib[ol.expr.functions.EXTENT] = function(minX, maxX, minY, maxY) {
+ol.expr.lib[ol.expr.functions.EXTENT] = function(minX, maxX, minY, maxY,
+    opt_projection, opt_attribute) {
   var intersects = false;
-  var geometry = this.getGeometry();
+  var geometry = goog.isDef(opt_attribute) ?
+      this.getAttributes()[opt_attribute] : this.getGeometry();
   if (geometry) {
     intersects = ol.extent.intersects(geometry.getBounds(),
         [minX, maxX, minY, maxY]);
@@ -142,6 +153,75 @@ ol.expr.lib[ol.expr.functions.FID] = function(var_args) {
 };
 
 
+/**
+ * Determine if a feature attribute is like the provided value.
+ * @param {string} attribute The name of the attribute to test for.
+ * @param {string} value The value to test for.
+ * @param {string} wildCard The wildcard character to use.
+ * @param {string} singleChar The single character to use.
+ * @param {string} escapeChar The escape character to use.
+ * @param {boolean} matchCase Should we match case or not?
+ * @this {ol.Feature}
+ */
+ol.expr.lib[ol.expr.functions.LIKE] = function(attribute, value, wildCard,
+    singleChar, escapeChar, matchCase) {
+  if (wildCard == '.') {
+    throw new Error('"." is an unsupported wildCard character for ' +
+        'ol.filter.Comparison');
+  }
+  // set UMN MapServer defaults for unspecified parameters
+  wildCard = goog.isDef(wildCard) ? wildCard : '*';
+  singleChar = goog.isDef(singleChar) ? singleChar : '.';
+  escapeChar = goog.isDef(escapeChar) ? escapeChar : '!';
+  var val;
+  val = value.replace(
+      new RegExp('\\' + escapeChar + '(.|$)', 'g'), '\\$1');
+  val = value.replace(
+      new RegExp('\\' + singleChar, 'g'), '.');
+  val = value.replace(
+      new RegExp('\\' + wildCard, 'g'), '.*');
+  val = value.replace(
+      new RegExp('\\\\.\\*', 'g'), '\\' + wildCard);
+  val = value.replace(
+      new RegExp('\\\\\\.', 'g'), '\\' + singleChar);
+  var attributes = this.getAttributes();
+  var modifiers = (matchCase === false) ? 'gi' : 'g';
+  return new RegExp(val, modifiers).test(attributes[attribute]);
+};
+
+
+/**
+ * Case insensitive comparison for equality.
+ * @param {string} attribute Name of the attribute.
+ * @param {string} value Value to test for equality.
+ * @this {ol.Feature}
+ */
+ol.expr.lib[ol.expr.functions.IEQ] = function(attribute, value) {
+  var attributes = this.getAttributes();
+  if (goog.isString(value) && goog.isString(attributes[attribute])) {
+    return value.toUpperCase() == attributes[attribute].toUpperCase();
+  } else {
+    return value == attributes[attribute];
+  }
+};
+
+
+/**
+ * Case insensitive comparison for non-equality.
+ * @param {string} attribute Name of the attribute.
+ * @param {string} value Value to test for non-equality.
+ * @this {ol.Feature}
+ */
+ol.expr.lib[ol.expr.functions.INEQ] = function(attribute, value) {
+  var attributes = this.getAttributes();
+  if (goog.isString(value) && goog.isString(attributes[attribute])) {
+    return value.toUpperCase() == attributes[attribute].toUpperCase();
+  } else {
+    return value != attributes[attribute];
+  }
+};
+
+
 /**
  * Determine if a feature's default geometry is of the given type.
  * @param {ol.geom.GeometryType} type Geometry type.
@@ -156,3 +236,31 @@ ol.expr.lib[ol.expr.functions.GEOMETRY_TYPE] = function(type) {
   }
   return same;
 };
+
+
+ol.expr.lib[ol.expr.functions.INTERSECTS] = function(geom, opt_projection,
+    opt_attribute) {
+  throw new Error('Spatial function not implemented: ' +
+      ol.expr.functions.INTERSECTS);
+};
+
+
+ol.expr.lib[ol.expr.functions.WITHIN] = function(geom, opt_projection,
+    opt_attribute) {
+  throw new Error('Spatial function not implemented: ' +
+      ol.expr.functions.WITHIN);
+};
+
+
+ol.expr.lib[ol.expr.functions.CONTAINS] = function(geom, opt_projeciton,
+    opt_attribute) {
+  throw new Error('Spatial function not implemented: ' +
+      ol.expr.functions.CONTAINS);
+};
+
+
+ol.expr.lib[ol.expr.functions.DWITHIN] = function(geom, distance, units,
+    opt_projection, opt_attribute) {
+  throw new Error('Spatial function not implemented: ' +
+      ol.expr.functions.DWITHIN);
+};