Adding ArithemeticInterpreter, implementing OP_ADD

src/main/scala/org/scalacoin/marshallers/script/ScriptParser.scala

@@ -49,7 +49,10 @@ trait ScriptParser extends ScalacoinUtil {
           val op = ScriptOperationFactory.fromString(h).get
           val parsingHelper : ParsingHelper[String] = parseOperationString(op,accum,t)
           loop(parsingHelper.tail,parsingHelper.accum)
-
+        case h :: t if (tryParsingInt(h)) =>
+          //convert the string to int, then convert to hex
+          val int = h.toInt
+          loop(t, ScriptConstantImpl(int.toHexString) :: accum)
         case h :: t => loop(t, ScriptConstantImpl(h) :: accum)
         case Nil => accum
       }
@@ -176,6 +179,14 @@ trait ScriptParser extends ScalacoinUtil {
         ParsingHelper(tail,op :: accum)
     }
   }
+
+
+  /**
+   * Checks if a string can be cast to an int
+   * @param str
+   * @return
+   */
+  private def tryParsingInt(str : String) = try { str.toInt; true} catch { case _ : Throwable => false}
 }
 
 object ScriptParser extends ScriptParser

src/main/scala/org/scalacoin/script/arithmetic/ArithmeticInterpreter.scala

@@ -0,0 +1,49 @@
+package org.scalacoin.script.arithmetic
+
+import org.scalacoin.script.constant.{ScriptNumber, ScriptNumberImpl, ScriptConstantImpl, ScriptToken}
+
+/**
+ * Created by chris on 1/25/16.
+ */
+trait ArithmeticInterpreter {
+
+  /**
+   * 	a is added to b.
+   * @param stack
+   * @param script
+   * @return
+   */
+  def opAdd(stack : List[ScriptToken], script : List[ScriptToken]) : (List[ScriptToken],List[ScriptToken]) = {
+    require(script.headOption.isDefined && script.head == OP_ADD, "Script top must be OP_ADD")
+    require(stack.size > 1, "Stack size must be 2 or more perform an OP_ADD")
+
+    val b : Int  = intFromScriptToken(stack.head)
+    val a : Int = intFromScriptToken(stack(1))
+
+    val result = numberToScriptToken(a + b)
+    (result :: stack.slice(2,stack.size), script.tail)
+  }
+
+
+  /**
+   * Wraps a scala number into a script token for the script language
+   * @param num
+   * @return
+   */
+  private def numberToScriptToken(num : Int) : ScriptToken = {
+    if (num < 76) ScriptNumberImpl(num)
+    else ScriptConstantImpl(num.toHexString)
+  }
+
+
+  /**
+   * Converts a script token to an integer
+   * @param token
+   * @return
+   */
+  private def intFromScriptToken(token : ScriptToken) : Int = token match {
+    case x : ScriptNumber => x.opCode
+    case x : ScriptConstantImpl => Integer.parseInt(x.hex,16)
+  }
+
+}

src/main/scala/org/scalacoin/script/interpreter/ScriptInterpreter.scala

@@ -1,6 +1,7 @@
 package org.scalacoin.script.interpreter
 
 import org.scalacoin.protocol.script.{ScriptSignature, ScriptPubKey}
+import org.scalacoin.script.arithmetic.{ArithmeticInterpreter, OP_ADD}
 import org.scalacoin.script.bitwise.{OP_EQUAL, BitwiseInterpreter, OP_EQUALVERIFY}
 import org.scalacoin.script.constant._
 import org.scalacoin.script.control.{OP_NOTIF, OP_IF, ControlOperationsInterpreter}
@@ -14,7 +15,7 @@ import scala.annotation.tailrec
  * Created by chris on 1/6/16.
  */
 trait ScriptInterpreter extends CryptoInterpreter with StackInterpreter with ControlOperationsInterpreter
-  with BitwiseInterpreter with ConstantInterpreter {
+  with BitwiseInterpreter with ConstantInterpreter with ArithmeticInterpreter {
 
   private def logger = LoggerFactory.getLogger(this.getClass().toString)
   /**
@@ -39,6 +40,8 @@ trait ScriptInterpreter extends CryptoInterpreter with StackInterpreter with Con
         case OP_DUP :: t => loop(opDup(stack,script))
         case OP_DEPTH :: t => loop(opDepth(stack,script))
 
+        //arithmetic operaetions
+        case OP_ADD :: t => loop(opAdd(stack,script))
         //bitwise operations
         case OP_EQUAL :: t => {
           val (newStack,newScript) = equal(stack, script)

src/test/scala/org/scalacoin/marshallers/script/ScriptParserTest.scala

@@ -1,7 +1,8 @@
 package org.scalacoin.marshallers.script
 
+import org.scalacoin.script.arithmetic.OP_ADD
 import org.scalacoin.script.bitwise.OP_EQUAL
-import org.scalacoin.script.constant.ScriptConstantImpl
+import org.scalacoin.script.constant.{OP_1NEGATE, ScriptConstantImpl}
 import org.scalacoin.util.{ScalacoinUtil, TestUtil}
 import org.scalatest.{FlatSpec, MustMatchers}
 
@@ -51,6 +52,12 @@ class ScriptParserTest extends FlatSpec with MustMatchers with ScriptParser with
     parse(str) must equal (List(ScriptConstantImpl("0100")))
   }
 
+  it must "parse a script signature with a decimal constant in it" in {
+    val str = "0x4f 1000 ADD"
+    //0x3e8 == 1000
+    parse(str) must equal (List(OP_1NEGATE, ScriptConstantImpl("3e8"), OP_ADD))
+  }
+
 
 
 }

src/test/scala/org/scalacoin/script/ScriptOperationFactoryTest.scala

@@ -60,4 +60,10 @@ class ScriptOperationFactoryTest extends FlatSpec with MustMatchers {
     spliceOperation.get must be (OP_SUBSTR)
   }
 
+  it must "find OP_1NEGATE from its hex representation" in {
+    val negateOperation = ScriptOperationFactory.fromHex("4f")
+    negateOperation.isDefined must be (true)
+    negateOperation.get must be (OP_1NEGATE)
+  }
+
 }

src/test/scala/org/scalacoin/script/arithmetic/ArithmeticInterpreterTest.scala

@@ -0,0 +1,46 @@
+package org.scalacoin.script.arithmetic
+
+import org.scalacoin.script.constant.{ScriptConstantImpl, ScriptNumberImpl}
+import org.scalatest.{FlatSpec, MustMatchers}
+
+/**
+ * Created by chris on 1/25/16.
+ */
+class ArithmeticInterpreterTest extends FlatSpec with MustMatchers with ArithmeticInterpreter {
+
+  "ArithmeticInterpreter" must "perform an OP_ADD correctly" in {
+    val stack = List(ScriptNumberImpl(1), ScriptNumberImpl(2))
+    val script = List(OP_ADD)
+    val (newStack,newScript) = opAdd(stack,script)
+    newStack.head must be (ScriptNumberImpl(3))
+    newScript.isEmpty must be (true)
+  }
+
+  it must "perform an OP_ADD correctly on ScriptConstantImpl" in {
+    //0x64 is the hexadecimal representation for 100
+    val stack = List(ScriptConstantImpl("64"), ScriptConstantImpl("64"))
+    val script = List(OP_ADD)
+    val (newStack,newScript) = opAdd(stack,script)
+    //0xC8 is 200 in hex
+    newStack.head must be (ScriptConstantImpl("c8"))
+    newScript.isEmpty must be (true)
+  }
+
+  it must "perform an OP_ADD correctly on a ScriptConstant & ScriptNumber that are used as the args" in {
+    val stack = List(ScriptNumberImpl(1), ScriptConstantImpl("64"))
+    val script = List(OP_ADD)
+    val (newStack,newScript) = opAdd(stack,script)
+    //0x65 is 101 in hex
+    newStack.head must be (ScriptConstantImpl("65"))
+    newScript.isEmpty must be (true)
+  }
+
+  it must "perform an OP_ADD correctly on a a negative number" in {
+    val stack = List(ScriptConstantImpl("3e8"), ScriptNumberImpl(-1))
+    val script = List(OP_ADD)
+    val (newStack,newScript) = opAdd(stack,script)
+
+    newStack.head must be (ScriptConstantImpl("3e7"))
+    newScript.isEmpty must be (true)
+  }
+}