source: Dev/trunk/src/client/dojox/charting/scaler/common.js

define(["dojo/_base/lang"], function(lang){

        var eq = function(/*Number*/ a, /*Number*/ b){
                // summary:
                //              compare two FP numbers for equality
                return Math.abs(a - b) <= 1e-6 * (Math.abs(a) + Math.abs(b));   // Boolean
        };
        
        var common = lang.getObject("dojox.charting.scaler.common", true);
        
        var testedModules = {};

        return lang.mixin(common, {
                doIfLoaded: function(moduleName, ifloaded, ifnotloaded){
                        if(testedModules[moduleName] == undefined){
                                try{
                                        testedModules[moduleName] = require(moduleName);
                                }catch(e){
                                        testedModules[moduleName] = null;
                                }
                        }
                        if(testedModules[moduleName]){
                                return ifloaded(testedModules[moduleName]);
                        }else{
                                return ifnotloaded();
                        }
                },
                getNumericLabel: function(/*Number*/ number, /*Number*/ precision, /*Object*/ kwArgs){
                        var def = "";
                        common.doIfLoaded("dojo/number", function(numberLib){
                                def = (kwArgs.fixed ? numberLib.format(number, {places : precision < 0 ? -precision : 0}) :
                                        numberLib.format(number)) || "";
                        }, function(){
                                def = kwArgs.fixed ? number.toFixed(precision < 0 ? -precision : 0) : number.toString();
                        });
                        if(kwArgs.labelFunc){
                                var r = kwArgs.labelFunc(def, number, precision);
                                if(r){ return r; }
                                // else fall through to the regular labels search
                        }
                        if(kwArgs.labels){
                                // classic binary search
                                // TODO: working only if the array is sorted per value should be better documented or sorted automatically
                                var l = kwArgs.labels, lo = 0, hi = l.length;
                                while(lo < hi){
                                        var mid = Math.floor((lo + hi) / 2), val = l[mid].value;
                                        if(val < number){
                                                lo = mid + 1;
                                        }else{
                                                hi = mid;
                                        }
                                }
                                // lets take into account FP errors
                                if(lo < l.length && eq(l[lo].value, number)){
                                        return l[lo].text;
                                }
                                --lo;
                                if(lo >= 0 && lo < l.length && eq(l[lo].value, number)){
                                        return l[lo].text;
                                }
                                lo += 2;
                                if(lo < l.length && eq(l[lo].value, number)){
                                        return l[lo].text;
                                }
                                // otherwise we will produce a number
                        }
                        return def;
                }
        });
});