implement int, uint decoding

src/solidity/types/Int.js

@@ -1,4 +1,7 @@
 'use strict'
+var util = require('./util')
+var BN = require('ethereumjs-util').BN
+var ethutil = require('ethereumjs-util')
 
 function Int (storageBytes) {
   this.storageSlots = 1
@@ -7,7 +10,22 @@ function Int (storageBytes) {
 }
 
 Int.prototype.decodeFromStorage = function (location, storageContent) {
-  return '<not implemented yet>'
+  var slot = ethutil.bufferToHex(ethutil.setLengthLeft(location.slot, 32))
+  if (!storageContent[slot]) {
+    return '0'
+  }
+  var value = util.extractValue(storageContent[slot], this.storageBytes, location)
+  var bigNumber = new BN(value.replace('0x', ''), 16)
+  if (isNegative(bigNumber, this.storageBytes)) {
+    return ethutil.fromSigned(ethutil.toUnsigned(bigNumber)).toString(10)
+  } else {
+    return bigNumber.toString(10)
+  }
 }
 
 module.exports = Int
+
+function isNegative (value, storageBytes) {
+  var binary = value.toString(2)
+  return binary.length < storageBytes ? false : binary[0] === '1'
+}

src/solidity/types/Uint.js

@@ -1,4 +1,7 @@
 'use strict'
+var util = require('./util')
+var ethutil = require('ethereumjs-util')
+var BN = require('ethereumjs-util').BN
 
 function Uint (storageBytes) {
   this.storageSlots = 1
@@ -7,7 +10,13 @@ function Uint (storageBytes) {
 }
 
 Uint.prototype.decodeFromStorage = function (location, storageContent) {
-  return '<not implemented yet>'
+  var slot = ethutil.bufferToHex(ethutil.setLengthLeft(location.slot, 32))
+  if (!storageContent[slot]) {
+    return '0'
+  }
+  var value = util.extractValue(storageContent[slot], this.storageBytes, location)
+  var bigNumber = new BN(value.replace('0x', ''), 16)
+  return bigNumber.toString(10)
 }
 
 module.exports = Uint

src/solidity/types/util.js

@@ -0,0 +1,13 @@
+module.exports = {
+  extractValue: function (slotValue, storageBytes, location) {
+    slotValue = slotValue.replace('0x', '')
+    var offset = slotValue.length - 2 * location.offset - storageBytes / 4
+    if (offset >= 0) {
+      return '0x' + slotValue.substr(offset, storageBytes / 4)
+    } else if (offset + storageBytes > 0) {
+      return '0x' + slotValue.substr(0, storageBytes / 4 + offset)
+    } else {
+      return '0x0'
+    }
+  }
+}