Box.getReg with computable index

.gitignore

@@ -11,6 +11,7 @@
 
 yarn.lock
 *.log
+yarn.lock
 docs/spec/out/
 test-out/
 flamegraphs/

core/shared/src/main/scala/sigma/SigmaDsl.scala

@@ -459,6 +459,23 @@ trait Header {
 
   /** Miner votes for changing system parameters. */
   def votes: Coll[Byte] //3 bytes
+
+  /** Bytes which are coming from future versions of the protocol, so
+    * their meaning is not known to current version of Sigma, but they
+    * are stored to get the same id as future version users.
+    */
+  def unparsedBytes: Coll[Byte]
+
+  /**
+    * @return header bytes without proof of work, a PoW is generated over them
+    */
+  def serializeWithoutPoW: Coll[Byte]
+
+  /**
+    * @return result of header's proof-of-work validation
+    */
+  def checkPow: Boolean
+
 }
 
 /** Runtime representation of Context ErgoTree type.

core/shared/src/main/scala/sigma/reflection/ReflectionData.scala

@@ -346,6 +346,9 @@ object ReflectionData {
         },
         mkMethod(clazz, "powDistance", Array[Class[_]]()) { (obj, _) =>
           obj.asInstanceOf[Header].powDistance
+        },
+        mkMethod(clazz, "checkPow", Array[Class[_]]()) { (obj, _) =>
+          obj.asInstanceOf[Header].checkPow
         }
       )
     )

core/shared/src/main/scala/sigma/util/NBitsUtils.scala

@@ -0,0 +1,84 @@
+package sigma.util
+
+import java.math.BigInteger
+
+object NBitsUtils {
+
+  /**
+    * <p>The "compact" format is a representation of a whole number N using an unsigned 32 bit number similar to a
+    * floating point format. The most significant 8 bits are the unsigned exponent of base 256. This exponent can
+    * be thought of as "number of bytes of N". The lower 23 bits are the mantissa. Bit number 24 (0x800000) represents
+    * the sign of N. Therefore, N = (-1^sign) * mantissa * 256^(exponent-3).</p>
+    *
+    * <p>Satoshi's original implementation used BN_bn2mpi() and BN_mpi2bn(). MPI uses the most significant bit of the
+    * first byte as sign. Thus 0x1234560000 is compact 0x05123456 and 0xc0de000000 is compact 0x0600c0de. Compact
+    * 0x05c0de00 would be -0x40de000000.</p>
+    *
+    * <p>Bitcoin only uses this "compact" format for encoding difficulty targets, which are unsigned 256bit quantities.
+    * Thus, all the complexities of the sign bit and using base 256 are probably an implementation accident.</p>
+    */
+  def decodeCompactBits(compact: Long): BigInt = {
+    val size: Int = (compact >> 24).toInt & 0xFF
+    val bytes: Array[Byte] = new Array[Byte](4 + size)
+    bytes(3) = size.toByte
+    if (size >= 1) bytes(4) = ((compact >> 16) & 0xFF).toByte
+    if (size >= 2) bytes(5) = ((compact >> 8) & 0xFF).toByte
+    if (size >= 3) bytes(6) = (compact & 0xFF).toByte
+    decodeMPI(bytes)
+  }
+
+  /**
+    * @see Utils#decodeCompactBits(long)
+    */
+  def encodeCompactBits(requiredDifficulty: BigInt): Long = {
+    val value = requiredDifficulty.bigInteger
+    var result: Long = 0L
+    var size: Int = value.toByteArray.length
+    if (size <= 3) {
+      result = value.longValue << 8 * (3 - size)
+    } else {
+      result = value.shiftRight(8 * (size - 3)).longValue
+    }
+    // The 0x00800000 bit denotes the sign.
+    // Thus, if it is already set, divide the mantissa by 256 and increase the exponent.
+    if ((result & 0x00800000L) != 0) {
+      result >>= 8
+      size += 1
+    }
+    result |= size << 24
+    val a: Int = if (value.signum == -1) 0x00800000 else 0
+    result |= a
+    result
+  }
+
+
+  /** Parse 4 bytes from the byte array (starting at the offset) as unsigned 32-bit integer in big endian format. */
+  def readUint32BE(bytes: Array[Byte]): Long = ((bytes(0) & 0xffL) << 24) | ((bytes(1) & 0xffL) << 16) | ((bytes(2) & 0xffL) << 8) | (bytes(3) & 0xffL)
+
+  /**
+    * MPI encoded numbers are produced by the OpenSSL BN_bn2mpi function. They consist of
+    * a 4 byte big endian length field, followed by the stated number of bytes representing
+    * the number in big endian format (with a sign bit).
+    *
+    */
+  private def decodeMPI(mpi: Array[Byte]): BigInteger = {
+
+    val length: Int = readUint32BE(mpi).toInt
+    val buf = new Array[Byte](length)
+    System.arraycopy(mpi, 4, buf, 0, length)
+
+    if (buf.length == 0) {
+      BigInteger.ZERO
+    } else {
+      val isNegative: Boolean = (buf(0) & 0x80) == 0x80
+      if (isNegative) buf(0) = (buf(0) & 0x7f).toByte
+      val result: BigInteger = new BigInteger(buf)
+      if (isNegative) {
+        result.negate
+      } else {
+        result
+      }
+    }
+  }
+
+}

data/shared/src/main/scala/org/ergoplatform/ErgoHeader.scala

@@ -0,0 +1,182 @@
+package org.ergoplatform
+
+import scorex.crypto.authds.ADDigest
+import scorex.crypto.hash.{Blake2b256, Digest32}
+import scorex.util.ModifierId
+import sigma.Colls
+import sigma.crypto.{BigIntegers, CryptoConstants, EcPointType}
+import sigma.serialization.{GroupElementSerializer, SigmaByteReader, SigmaByteWriter, SigmaSerializer}
+
+import scala.runtime.ScalaRunTime
+import scala.util.hashing.MurmurHash3
+
+
+
+/**
+  * Solution for an Autolykos PoW puzzle.
+  *
+  * In Autolykos v.1 all the four fields are used, in Autolykos v.2 only pk and n fields are used.
+  *
+  * @param pk - miner public key. Should be used to collect block rewards
+  * @param w  - one-time public key. Prevents revealing of miners secret
+  * @param n  - nonce (8 bytes)
+  * @param d  - distance between pseudo-random number, corresponding to nonce `n` and a secret,
+  *           corresponding to `pk`. The lower `d` is, the harder it was to find this solution.
+  */
+class AutolykosSolution(val pk: EcPointType,
+                        val w: EcPointType,
+                        val n: Array[Byte],
+                        val d: BigInt) {
+
+    val encodedPk: Array[Byte] = GroupElementSerializer.toBytes(pk)
+
+    override def hashCode(): Int = {
+        var h = pk.hashCode()
+        h = h * 31 + w.hashCode()
+        h = h * 31 + MurmurHash3.arrayHash(n)
+        h = h * 31 + d.hashCode()
+        h
+    }
+
+    override def equals(obj: Any): Boolean = {
+        obj match {
+            case other: AutolykosSolution =>
+                this.pk == other.pk &&
+                  this.n.sameElements(other.n) &&
+                  this.w == other.w &&
+                  this.d == other.d
+
+            case _ => false
+        }
+    }
+}
+
+
+object AutolykosSolution {
+    // "pk", "w" and "d" values for Autolykos v2 solution, where they not passed from outside
+    val pkForV2: EcPointType = CryptoConstants.dlogGroup.identity
+    val wForV2: EcPointType = CryptoConstants.dlogGroup.generator
+    val dForV2: BigInt = 0
+
+    object sigmaSerializerV1 extends SigmaSerializer[AutolykosSolution, AutolykosSolution] {
+        override def serialize(s: AutolykosSolution, w: SigmaByteWriter): Unit = {
+            GroupElementSerializer.serialize(s.pk, w)
+            GroupElementSerializer.serialize(s.w, w)
+            require(s.n.length == 8) // non-consensus check on prover side
+            w.putBytes(s.n)
+            val dBytes = BigIntegers.asUnsignedByteArray(s.d.bigInteger)
+            w.putUByte(dBytes.length)
+            w.putBytes(dBytes)
+        }
+
+        override def parse(r: SigmaByteReader): AutolykosSolution = {
+            val pk = GroupElementSerializer.parse(r)
+            val w = GroupElementSerializer.parse(r)
+            val nonce = r.getBytes(8)
+            val dBytesLength = r.getUByte()
+            val d = BigInt(BigIntegers.fromUnsignedByteArray(r.getBytes(dBytesLength)))
+            new AutolykosSolution(pk, w, nonce, d)
+        }
+    }
+
+    object sigmaSerializerV2 extends SigmaSerializer[AutolykosSolution, AutolykosSolution] {
+        override def serialize(s: AutolykosSolution, w: SigmaByteWriter): Unit = {
+            GroupElementSerializer.serialize(s.pk, w)
+            require(s.n.length == 8) // non-consensus check on prover side
+            w.putBytes(s.n)
+        }
+
+        override def parse(r: SigmaByteReader): AutolykosSolution = {
+            val pk = GroupElementSerializer.parse(r)
+            val nonce = r.getBytes(8)
+            new AutolykosSolution(pk, wForV2, nonce, dForV2)
+        }
+    }
+}
+
+/**
+  * Header of a block. It authenticates link to a previous block, other block sections
+  * (transactions, UTXO set transformation proofs, extension), UTXO set, votes for parameters
+  * to be changed and proof-of-work related data.
+  *
+  * @param version - protocol version
+  * @param parentId - id of a parent block header
+  * @param ADProofsRoot - digest of UTXO set transformation proofs
+  * @param stateRoot - AVL+ tree digest of UTXO set (after the block)
+  * @param transactionsRoot - Merkle tree digest of transactions in the block (BlockTransactions section)
+  * @param timestamp - block generation time reported by a miner
+  * @param nBits - difficulty encoded
+  * @param height - height of the block (genesis block height == 1)
+  * @param extensionRoot - Merkle tree digest of the extension section of the block
+  * @param powSolution - solution for the proof-of-work puzzle
+  * @param votes - votes for changing system parameters
+  * @param unparsedBytes - bytes from future versions of the protocol our version can't parse
+  * @param _bytes - serialized bytes of the header when not `null`
+  */
+case class ErgoHeader(override val version: ErgoHeader.Version,
+                      override val parentId: ModifierId,
+                      override val ADProofsRoot: Digest32,
+                      override val stateRoot: ADDigest, //33 bytes! extra byte with tree height here!
+                      override val transactionsRoot: Digest32,
+                      override val timestamp: ErgoHeader.Timestamp,
+                      override val nBits: Long, //actually it is unsigned int
+                      override val height: Int,
+                      override val extensionRoot: Digest32,
+                      powSolution: AutolykosSolution,
+                      override val votes: Array[Byte], //3 bytes
+                      override val unparsedBytes: Array[Byte],
+                      _bytes: Array[Byte]) extends
+  HeaderWithoutPow(version, parentId, ADProofsRoot, stateRoot, transactionsRoot, timestamp,
+    nBits, height, extensionRoot, votes, unparsedBytes) {
+
+    lazy val bytes = if(_bytes != null) {
+        _bytes
+    } else {
+        ErgoHeader.sigmaSerializer.toBytes(this)
+    }
+
+    lazy val serializedId: Array[Byte] = Blake2b256.hash(bytes)
+
+    lazy val id = Colls.fromArray(serializedId)
+
+    override def hashCode(): Int = id.hashCode()
+
+    override def equals(other: Any): Boolean = other match {
+        case h: ErgoHeader => h.id == this.id
+        case _ => false
+    }
+}
+
+
+object ErgoHeader {
+
+    type Timestamp = Long
+
+    type Version = Byte
+
+    object sigmaSerializer extends SigmaSerializer[ErgoHeader, ErgoHeader] {
+        override def serialize(hdr: ErgoHeader, w: SigmaByteWriter): Unit = {
+            HeaderWithoutPowSerializer.serialize(hdr, w)
+            if (hdr.version == 1) {
+                AutolykosSolution.sigmaSerializerV1.serialize(hdr.powSolution, w)
+            } else {
+                AutolykosSolution.sigmaSerializerV2.serialize(hdr.powSolution, w)
+            }
+        }
+
+        override def parse(r: SigmaByteReader): ErgoHeader = {
+            val start = r.position
+            val headerWithoutPow = HeaderWithoutPowSerializer.parse(r)
+            val powSolution = if (headerWithoutPow.version == 1) {
+                AutolykosSolution.sigmaSerializerV1.parse(r)
+            } else {
+                AutolykosSolution.sigmaSerializerV2.parse(r)
+            }
+            val end = r.position
+            val len = end - start
+            r.position = start
+            val headerBytes = r.getBytes(len) // also moves position back to end
+            headerWithoutPow.toHeader(powSolution, headerBytes)
+        }
+    }
+}