move sha3 function outside of solidity code

src/helpers/util.js

 'use strict'
+var ethutil = require('ethereumjs-util')
+
 module.exports = {
   /*
     ints: IntArray
@@ -115,7 +117,19 @@ module.exports = {
   */
   findCall: findCall,
 
-  buildCallPath: buildCallPath
+  buildCallPath: buildCallPath,
+
+  /**
+  * sha3 the given @arg value
+  *
+  * @param {String} value - value to sha3
+  * @return {Object} - return sha3ied value
+  */
+  sha3: function (value) {
+    var ret = ethutil.bufferToHex(ethutil.setLengthLeft(value, 32))
+    ret = ethutil.sha3(ret)
+    return ethutil.bufferToHex(ret)
+  }
 }
 
 /**

src/solidity/types/ArrayType.js

 'use strict'
 var util = require('./util')
+var helper = require('../../helpers/util')
 var BN = require('ethereumjs-util').BN
 var RefType = require('./RefType')
 
@@ -33,7 +34,7 @@ class ArrayType extends RefType {
     }
     if (this.arraySize === 'dynamic') {
       size = util.toBN('0x' + slotValue)
-      currentLocation.slot = util.sha3(location.slot)
+      currentLocation.slot = helper.sha3(location.slot)
     } else {
       size = new BN(this.arraySize)
     }

src/solidity/types/DynamicByteArray.js

 'use strict'
 var util = require('./util')
+var helper = require('../../helpers/util')
 var BN = require('ethereumjs-util').BN
 var RefType = require('./RefType')
 
@@ -13,7 +14,7 @@ class DynamicByteArray extends RefType {
     var bn = new BN(value, 16)
     if (bn.testn(0)) {
       var length = bn.div(new BN(2))
-      var dataPos = new BN(util.sha3(location.slot).replace('0x', ''), 16)
+      var dataPos = new BN(helper.sha3(location.slot).replace('0x', ''), 16)
       var ret = ''
       var currentSlot = await util.readFromStorage(dataPos, storageContent)
       while (length.gt(ret.length) && ret.length < 32000) {

src/solidity/types/util.js

@@ -7,7 +7,6 @@ module.exports = {
   decodeIntFromHex: decodeIntFromHex,
   extractHexValue: extractHexValue,
   extractHexByteSlice: extractHexByteSlice,
-  sha3: sha3,
   toBN: toBN,
   add: add,
   extractLocation: extractLocation,
@@ -67,12 +66,6 @@ async function extractHexValue (location, storageContent, byteLength) {
   return extractHexByteSlice(slotvalue, byteLength, location.offset)
 }
 
-function sha3 (slot) {
-  var remoteSlot = ethutil.bufferToHex(ethutil.setLengthLeft(slot, 32))
-  var key = ethutil.sha3(remoteSlot)
-  return ethutil.bufferToHex(key)
-}
-
 function toBN (value) {
   if (value instanceof BN) {
     return value