Novacoin/CScript.cs

   1 \feff/**
   2  *  Novacoin classes library
   3  *  Copyright (C) 2015 Alex D. (balthazar.ad@gmail.com)
   4
   5  *  This program is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU Affero General Public License as
   7  *  published by the Free Software Foundation, either version 3 of the
   8  *  License, or (at your option) any later version.
   9
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU Affero General Public License for more details.
  14
  15  *  You should have received a copy of the GNU Affero General Public License
  16  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 using System;
  20 using System.Linq;
  21 using System.Text;
  22 using System.Collections.Generic;
  23
  24 namespace Novacoin
  25 {
  26     public class CScriptException : Exception
  27     {
  28         public CScriptException()
  29         {
  30         }
  31
  32         public CScriptException(string message)
  33             : base(message)
  34         {
  35         }
  36
  37         public CScriptException(string message, Exception inner)
  38             : base(message, inner)
  39         {
  40         }
  41     }
  42
  43     /// <summary>
  44     /// Representation of script code
  45     /// </summary>
  46         public class CScript
  47         {
  48         private List<byte> codeBytes;
  49
  50         /// <summary>
  51         /// Initializes an empty instance of CScript
  52         /// </summary>
  53                 public CScript ()
  54                 {
  55             codeBytes = new List<byte>();
  56                 }
  57
  58         /// <summary>
  59         /// Initializes new instance of CScript and fills it with supplied bytes
  60         /// </summary>
  61         /// <param name="bytes">Enumerator interface for byte sequence</param>
  62         public CScript(IEnumerable<byte> bytes)
  63         {
  64             codeBytes = new List<byte>(bytes);
  65         }
  66
  67         /// <summary>
  68         /// Return a new instance of ByteQueue object for current code bytes
  69         /// </summary>
  70         /// <returns></returns>
  71         public ByteQueue GetByteQUeue()
  72         {
  73              return new ByteQueue(codeBytes);
  74         }
  75
  76         /// <summary>
  77         /// Adds specified operation to opcode bytes list
  78         /// </summary>
  79         /// <param name="opcode"></param>
  80         public void AddOp(instruction opcode)
  81         {
  82             if (opcode < instruction.OP_0 || opcode > instruction.OP_INVALIDOPCODE)
  83             {
  84                 throw new CScriptException("CScript::AddOp() : invalid opcode");
  85             }
  86
  87             codeBytes.Add((byte)opcode);
  88         }
  89
  90         /// <summary>
  91         /// Adds hash to opcode bytes list.
  92         ///    New items are added in this format:
  93         ///    hash_length_byte hash_bytes
  94         /// </summary>
  95         /// <param name="hash">Hash160 instance</param>
  96         public void AddHash(Hash160 hash)
  97         {
  98             codeBytes.Add((byte)hash.hashSize);
  99             codeBytes.AddRange(hash.hashBytes);
 100         }
 101
 102         /// <summary>
 103         /// Adds hash to opcode bytes list.
 104         ///    New items are added in this format:
 105         ///    hash_length_byte hash_bytes
 106         /// </summary>
 107         /// <param name="hash">Hash256 instance</param>
 108         public void AddHash(Hash256 hash)
 109         {
 110             codeBytes.Add((byte)hash.hashSize);
 111             codeBytes.AddRange(hash.hashBytes);
 112         }
 113
 114         /// <summary>
 115         /// Create new OP_PUSHDATAn operator and add it to opcode bytes list
 116         /// </summary>
 117         /// <param name="dataBytes">Set of data bytes</param>
 118         public void PushData(byte[] dataBytes)
 119         {
 120             var nCount = dataBytes.LongLength;
 121
 122             if (nCount < (int)instruction.OP_PUSHDATA1)
 123             {
 124                 // OP_0 and OP_FALSE
 125                 codeBytes.Add((byte)nCount);
 126             }
 127             else if (nCount < 0xff)
 128             {
 129                 // OP_PUSHDATA1 0x01 [0x5a]
 130                 codeBytes.Add((byte)instruction.OP_PUSHDATA1);
 131                 codeBytes.Add((byte)nCount);
 132             }
 133             else if (nCount < 0xffff)
 134             {
 135                 // OP_PUSHDATA1 0x00 0x01 [0x5a]
 136                 codeBytes.Add((byte)instruction.OP_PUSHDATA2);
 137
 138                 byte[] szBytes = Interop.BEBytes((ushort)nCount);
 139                 codeBytes.AddRange(szBytes);
 140             }
 141             else if (nCount < 0xffffffff)
 142             {
 143                 // OP_PUSHDATA1 0x00 0x00 0x00 0x01 [0x5a]
 144                 codeBytes.Add((byte)instruction.OP_PUSHDATA4);
 145
 146                 byte[] szBytes = Interop.BEBytes((uint)nCount);
 147                 codeBytes.AddRange(szBytes);
 148             }
 149
 150             // Add data bytes
 151             codeBytes.AddRange(dataBytes);
 152         }
 153
 154         /// <summary>
 155         /// Scan code bytes for pattern
 156         /// </summary>
 157         /// <param name="pattern">Pattern sequence</param>
 158         /// <returns>Matches enumerator</returns>
 159         private IEnumerable<int> FindPattern(byte[] pattern)
 160         {
 161             for (int i = 0; i < codeBytes.Count; i++)
 162             {
 163                 if (codeBytes.Skip(i).Take(pattern.Length).SequenceEqual(pattern))
 164                 {
 165                     yield return i;
 166                 }
 167             }
 168         }
 169
 170         /// <summary>
 171         /// Scan code bytes for pattern and remove it
 172         /// </summary>
 173         /// <param name="pattern">Pattern sequence</param>
 174         /// <returns>Matches number</returns>
 175         public int RemovePattern(byte[] pattern)
 176         {
 177             var resultBytes = new List<byte>(codeBytes);
 178             int count = 0;
 179
 180             foreach (int i in FindPattern(pattern))
 181             {
 182                 resultBytes.RemoveRange(i - count * pattern.Length, pattern.Length);
 183                 count++;
 184             }
 185
 186             codeBytes = resultBytes;
 187
 188             return count;
 189         }
 190
 191         /// <summary>
 192         /// Is it true that script doesn't contain anything except push value operations?
 193         /// </summary>
 194         public bool IsPushOnly
 195         {
 196             get
 197             {
 198                 var wCodeBytes = new ByteQueue(codeBytes);
 199
 200                 instruction opcode; // Current opcode
 201                 byte[] pushArgs; // OP_PUSHDATAn argument
 202
 203                 // Scan opcodes sequence
 204                 while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 205                 {
 206                     if (opcode > instruction.OP_16)
 207                     {
 208                         // We don't allow control opcodes here
 209                         return false;
 210                     }
 211                 }
 212
 213                 return true;
 214             }
 215         }
 216
 217         /// <summary>
 218         /// Is it true that script doesn't contain non-canonical push operations?
 219         /// </summary>
 220         public bool HasOnlyCanonicalPushes
 221         {
 222             get
 223             {
 224                 var wCodeBytes = new ByteQueue(codeBytes);
 225
 226                 byte[] pushArgs; // OP_PUSHDATAn argument
 227                 instruction opcode; // Current opcode
 228
 229                 // Scan opcodes sequence
 230                 while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 231                 {
 232                     var data = pushArgs;
 233
 234                     if (opcode < instruction.OP_PUSHDATA1 && opcode > instruction.OP_0 && (data.Length == 1 && data[0] <= 16))
 235                     {
 236                         // Could have used an OP_n code, rather than a 1-byte push.
 237                         return false;
 238                     }
 239                     if (opcode == instruction.OP_PUSHDATA1 && data.Length < (int)instruction.OP_PUSHDATA1)
 240                     {
 241                         // Could have used a normal n-byte push, rather than OP_PUSHDATA1.
 242                         return false;
 243                     }
 244                     if (opcode == instruction.OP_PUSHDATA2 && data.Length <= 0xFF)
 245                     {
 246                         // Could have used an OP_PUSHDATA1.
 247                         return false;
 248                     }
 249                     if (opcode == instruction.OP_PUSHDATA4 && data.LongLength <= 0xFFFF)
 250                     {
 251                         // Could have used an OP_PUSHDATA2.
 252                         return false;
 253                     }
 254                 }
 255
 256                 return true;
 257             }
 258         }
 259
 260         /// <summary>
 261         /// Quick test for pay-to-script-hash CScripts
 262         /// </summary>
 263         public bool IsPayToScriptHash
 264         {
 265             get
 266             {
 267                 // Sender provides redeem script hash, receiver provides signature list and redeem script
 268                 // OP_HASH160 20 [20 byte hash] OP_EQUAL
 269                 return (codeBytes.Count() == 23 &&
 270                         codeBytes[0] == (byte)instruction.OP_HASH160 &&
 271                         codeBytes[1] == 0x14 && // 20 bytes hash length prefix
 272                         codeBytes[22] == (byte)instruction.OP_EQUAL);
 273             }
 274         }
 275
 276         /// <summary>
 277         /// Quick test for pay-to-pubkeyhash CScripts
 278         /// </summary>
 279         public bool IsPayToPubKeyHash
 280         {
 281             get
 282             {
 283                 // Sender provides hash of pubkey, receiver provides signature and pubkey
 284                 // OP_DUP OP_HASH160 20 [20 byte hash] OP_EQUALVERIFY OP_CHECKSIG
 285                 return (codeBytes.Count == 25 &&
 286                         codeBytes[0] == (byte)instruction.OP_DUP &&
 287                         codeBytes[1] == (byte)instruction.OP_HASH160 &&
 288                         codeBytes[2] == 0x14 && // 20 bytes hash length prefix
 289                         codeBytes[23] == (byte)instruction.OP_EQUALVERIFY &&
 290                         codeBytes[24] == (byte)instruction.OP_CHECKSIG);
 291             }
 292         }
 293
 294         /// <summary>
 295         /// Quick test for Null destination
 296         /// </summary>
 297         public bool IsNull
 298         {
 299             get { return codeBytes.Count == 0; }
 300         }
 301
 302         /// <summary>
 303         /// Pre-version-0.6, Bitcoin always counted CHECKMULTISIGs
 304         /// as 20 sigops. With pay-to-script-hash, that changed:
 305         /// CHECKMULTISIGs serialized in scriptSigs are
 306         /// counted more accurately, assuming they are of the form
 307         ///  ... OP_N CHECKMULTISIG ...
 308         /// </summary>
 309         /// <param name="fAccurate">Legacy mode flag</param>
 310         /// <returns>Amount of sigops</returns>
 311         public int GetSigOpCount(bool fAccurate)
 312         {
 313             var wCodeBytes = new ByteQueue(codeBytes);
 314
 315             instruction opcode; // Current opcode
 316             byte[] pushArgs; // OP_PUSHDATAn argument
 317
 318             int nCount = 0;
 319             var lastOpcode = instruction.OP_INVALIDOPCODE;
 320
 321             // Scan opcodes sequence
 322             while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 323             {
 324                 if (opcode == instruction.OP_CHECKSIG || opcode == instruction.OP_CHECKSIGVERIFY)
 325                 {
 326                     nCount++;
 327                 }
 328                 else if (opcode == instruction.OP_CHECKMULTISIG || opcode == instruction.OP_CHECKMULTISIGVERIFY)
 329                 {
 330                     if (fAccurate && lastOpcode >= instruction.OP_1 && lastOpcode <= instruction.OP_16)
 331                     {
 332                         nCount += ScriptCode.DecodeOP_N(lastOpcode);
 333                     }
 334                     else
 335                     {
 336                         nCount += 20;
 337                     }
 338                 }
 339             }
 340
 341             return nCount;
 342         }
 343
 344         /// <summary>
 345         /// Accurately count sigOps, including sigOps in
 346         /// pay-to-script-hash transactions
 347         /// </summary>
 348         /// <param name="scriptSig">pay-to-script-hash scriptPubKey</param>
 349         /// <returns>SigOps count</returns>
 350         public int GetSigOpCount(CScript scriptSig)
 351         {
 352             if (!IsPayToScriptHash)
 353             {
 354                 return GetSigOpCount(true);
 355             }
 356
 357             // This is a pay-to-script-hash scriptPubKey;
 358             // get the last item that the scriptSig
 359             // pushes onto the stack:
 360             ByteQueue wScriptSig = scriptSig.GetByteQUeue();
 361
 362             instruction opcode; // Current opcode
 363             byte[] pushArgs; // OP_PUSHDATAn argument
 364
 365             while (ScriptCode.GetOp(ref wScriptSig, out opcode, out pushArgs))
 366             {
 367                 if (opcode > instruction.OP_16)
 368                 {
 369                     return 0;
 370                 }
 371             }
 372
 373             /// ... and return its opcount:
 374             var subScript = new CScript(pushArgs);
 375
 376             return subScript.GetSigOpCount(true);
 377
 378         }
 379
 380         /// <summary>
 381         /// Set pay-to-pubkey destination.
 382         /// </summary>
 383         /// <param name="pubKey">Instance of CPubKey.</param>
 384         public void SetDestination(CPubKey pubKey)
 385         {
 386             codeBytes.Clear();
 387             PushData(pubKey.PublicBytes);
 388             AddOp(instruction.OP_CHECKSIG);
 389         }
 390
 391         /// <summary>
 392         /// Set pay-to-pubkeyhash destination
 393         /// </summary>
 394         /// <param name="ID">Public key hash</param>
 395         public void SetDestination(CKeyID ID)
 396         {
 397             codeBytes.Clear();
 398             AddOp(instruction.OP_DUP);
 399             AddOp(instruction.OP_HASH160);
 400             AddHash(ID);
 401             AddOp(instruction.OP_EQUALVERIFY);
 402             AddOp(instruction.OP_CHECKSIG);
 403         }
 404
 405         /// <summary>
 406         /// Set pay-to-scripthash destination
 407         /// </summary>
 408         /// <param name="ID">Script hash</param>
 409         public void SetDestination(CScriptID ID)
 410         {
 411             codeBytes.Clear();
 412             AddOp(instruction.OP_HASH160);
 413             AddHash(ID);
 414             AddOp(instruction.OP_EQUAL);
 415         }
 416
 417         /// <summary>
 418         /// Reset script code buffer.
 419         /// </summary>
 420         public void SetNullDestination()
 421         {
 422             codeBytes.Clear();
 423         }
 424
 425         /// <summary>
 426         /// Set multisig destination.
 427         /// </summary>
 428         /// <param name="nRequired">Amount of required signatures.</param>
 429         /// <param name="keys">Set of public keys.</param>
 430         public void SetMultiSig(int nRequired, CPubKey[] keys)
 431         {
 432             codeBytes.Clear();
 433             AddOp(ScriptCode.EncodeOP_N(nRequired));
 434
 435             foreach (var key in keys)
 436             {
 437                 PushData(key.PublicBytes);
 438             }
 439
 440             AddOp(ScriptCode.EncodeOP_N(keys.Length));
 441             AddOp(instruction.OP_CHECKMULTISIG);
 442         }
 443
 444         /// <summary>
 445         /// Access to script code.
 446         /// </summary>
 447         public byte[] Bytes
 448         {
 449             get { return codeBytes.ToArray(); }
 450         }
 451
 452         public CScriptID ScriptID
 453         {
 454             get { return new CScriptID(Hash160.Compute160(codeBytes.ToArray())); }
 455         }
 456
 457         /// <summary>
 458         /// Disassemble current script code
 459         /// </summary>
 460         /// <returns>Code listing</returns>
 461                 public override string ToString()
 462                 {
 463                         var sb = new StringBuilder();
 464             var wCodeBytes = new ByteQueue(codeBytes);
 465
 466             instruction opcode; // Current opcode
 467             byte[] pushArgs; // OP_PUSHDATAn argument
 468             while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 469             {
 470                 if (sb.Length != 0)
 471                 {
 472                     sb.Append(" ");
 473                 }
 474
 475                 if (0 <= opcode && opcode <= instruction.OP_PUSHDATA4)
 476                 {
 477                     sb.Append(ScriptCode.ValueString(pushArgs));
 478                 }
 479                 else
 480                 {
 481                     sb.Append(ScriptCode.GetOpName(opcode));
 482                 }
 483             }
 484
 485             return sb.ToString();
 486                 }
 487         }
 488 }