rename StringNumberMapping -> DictionaryCoder

js/data/feature_tree.js

@@ -6,7 +6,7 @@ var EXTENT = require('./bucket').EXTENT;
 var featureFilter = require('feature-filter');
 var StructArrayType = require('../util/struct_array');
 var Grid = require('../util/grid');
-var StringNumberMapping = require('../util/string_number_mapping');
+var DictionaryCoder = require('../util/dictionary_coder');
 var vt = require('vector-tile');
 var Protobuf = require('pbf');
 var GeoJSONFeature = require('../util/vectortile_to_geojson');
@@ -107,7 +107,7 @@ function translateDistance(translate) {
 FeatureTree.prototype.query = function(args, styleLayers, returnGeoJSON) {
     if (!this.vtLayers) {
         this.vtLayers = new vt.VectorTile(new Protobuf(new Uint8Array(this.rawTileData))).layers;
-        this.sourceLayerNumberMapping = new StringNumberMapping(this.vtLayers ? Object.keys(this.vtLayers).sort() : ['_geojsonTileLayer']);
+        this.sourceLayerCoder = new DictionaryCoder(this.vtLayers ? Object.keys(this.vtLayers).sort() : ['_geojsonTileLayer']);
     }
 
     var result = returnGeoJSON ?
@@ -190,7 +190,7 @@ FeatureTree.prototype.filterMatching = function(result, matching, array, queryGe
         var layerIDs = this.bucketLayerIDs[match.bucketIndex];
         if (filterLayerIDs && !arraysIntersect(filterLayerIDs, layerIDs)) continue;
 
-        var sourceLayerName = this.sourceLayerNumberMapping.numberToString[match.sourceLayerIndex];
+        var sourceLayerName = this.sourceLayerCoder.decode(match.sourceLayerIndex);
         var sourceLayer = this.vtLayers[sourceLayerName];
         var feature = sourceLayer.feature(match.featureIndex);
 
@@ -262,7 +262,7 @@ FeatureTree.prototype.filterMatching = function(result, matching, array, queryGe
 FeatureTree.prototype.makeGeoJSON = function(featureIndexArray, styleLayers) {
     if (!this.vtLayers) {
         this.vtLayers = new vt.VectorTile(new Protobuf(new Uint8Array(this.rawTileData))).layers;
-        this.sourceLayerNumberMapping = new StringNumberMapping(this.vtLayers ? Object.keys(this.vtLayers).sort() : ['_geojsonTileLayer']);
+        this.sourceLayerCoder = new DictionaryCoder(this.vtLayers ? Object.keys(this.vtLayers).sort() : ['_geojsonTileLayer']);
     }
 
     var result = {};
@@ -272,7 +272,7 @@ FeatureTree.prototype.makeGeoJSON = function(featureIndexArray, styleLayers) {
     var cachedLayerFeatures = {};
     for (var i = 0; i < featureIndexArray.length; i++) {
         var indexes = featureIndexArray.get(i);
-        var sourceLayerName = this.sourceLayerNumberMapping.numberToString[indexes.sourceLayerIndex];
+        var sourceLayerName = this.sourceLayerCoder.decode(indexes.sourceLayerIndex);
         var sourceLayer = this.vtLayers[sourceLayerName];
         var featureIndex = indexes.featureIndex;
 

js/source/worker_tile.js

@@ -4,7 +4,7 @@ var FeatureTree = require('../data/feature_tree');
 var CollisionTile = require('../symbol/collision_tile');
 var Bucket = require('../data/bucket');
 var CollisionBoxArray = require('../symbol/collision_box');
-var StringNumberMapping = require('../util/string_number_mapping');
+var DictionaryCoder = require('../util/dictionary_coder');
 
 module.exports = WorkerTile;
 
@@ -28,7 +28,7 @@ WorkerTile.prototype.parse = function(data, layers, actor, rawTileData, callback
     this.collisionBoxArray = new CollisionBoxArray();
     var collisionTile = new CollisionTile(this.angle, this.pitch, this.collisionBoxArray);
     var featureTree = new FeatureTree(this.coord, this.overscaling, collisionTile, data.layers);
-    var sourceLayerNumberMapping = new StringNumberMapping(data.layers ? Object.keys(data.layers).sort() : ['_geojsonTileLayer']);
+    var sourceLayerCoder = new DictionaryCoder(data.layers ? Object.keys(data.layers).sort() : ['_geojsonTileLayer']);
 
     var stats = { _total: 0 };
 
@@ -57,7 +57,7 @@ WorkerTile.prototype.parse = function(data, layers, actor, rawTileData, callback
             overscaling: this.overscaling,
             showCollisionBoxes: this.showCollisionBoxes,
             collisionBoxArray: this.collisionBoxArray,
-            sourceLayerIndex: sourceLayerNumberMapping.stringToNumber[layer['source-layer'] || '_geojsonTileLayer']
+            sourceLayerIndex: sourceLayerCoder.encode(layer['source-layer'] || '_geojsonTileLayer')
         });
         bucket.createFilter();
 

js/util/dictionary_coder.js

@@ -0,0 +1,21 @@
+'use strict';
+
+module.exports = DictionaryCoder;
+
+function DictionaryCoder(strings) {
+    this._stringToNumber = {};
+    this._numberToString = [];
+    for (var i = 0; i < strings.length; i++) {
+        var string = strings[i];
+        this._stringToNumber[string] = i;
+        this._numberToString[i] = string;
+    }
+}
+
+DictionaryCoder.prototype.encode = function(string) {
+    return this._stringToNumber[string];
+};
+
+DictionaryCoder.prototype.decode = function(n) {
+    return this._numberToString[n];
+};