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(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 instruction list
  78         /// </summary>
  79         /// <param name="opcode"></param>
  80         public void AddInstruction(instruction opcode)
  81         {
  82             if (opcode < instruction.OP_0 || opcode > instruction.OP_INVALIDOPCODE)
  83             {
  84                 throw new CScriptException("CScript::AddInstruction() : invalid instruction");
  85             }
  86
  87             codeBytes.Add((byte)opcode);
  88         }
  89
  90         /// <summary>
  91         /// Adds hash to instruction 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 instruction 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 instruction 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 0x01 0x00 [0x5a]
 136                 codeBytes.Add((byte)instruction.OP_PUSHDATA2);
 137
 138                 var szBytes = BitConverter.GetBytes((ushort)nCount);
 139                 codeBytes.AddRange(szBytes);
 140             }
 141             else if (nCount < 0xffffffff)
 142             {
 143                 // OP_PUSHDATA1 0x01 0x00 0x00 0x00 [0x5a]
 144                 codeBytes.Add((byte)instruction.OP_PUSHDATA4);
 145
 146                 var szBytes = BitConverter.GetBytes((uint)nCount);
 147                 codeBytes.AddRange(szBytes);
 148             }
 149
 150             // Add data bytes
 151             codeBytes.AddRange(dataBytes);
 152         }
 153
 154         /// <summary>
 155         /// Just insert data array without including any prefixes. Please make sure that you know what you're doing,
 156         ///    it is recommended to use AddInstruction, AddHash or PushData instead.
 157         /// </summary>
 158         /// <param name="dataBytes">Data bytes</param>
 159         public void AddRawData(byte[] dataBytes)
 160         {
 161             // Add data bytes
 162             codeBytes.AddRange(dataBytes);
 163         }
 164
 165         /// <summary>
 166         /// Scan pushed data bytes for pattern and, in case of exact match, remove it.
 167         /// </summary>
 168         /// <param name="pattern">Pattern sequence</param>
 169         /// <returns>Matches count</returns>
 170         public int RemovePattern(byte[] pattern)
 171         {
 172             // There is no sense to continue if pattern is empty or longer than script itself
 173             if (pattern.Length == 0 || pattern.Length > codeBytes.Count)
 174             {
 175                 return 0;
 176             }
 177
 178             var count = 0;
 179             var bq1 = new ByteQueue(codeBytes);
 180
 181             byte[] pushData;
 182             instruction opcode;
 183
 184             var newScript = new CScript();
 185
 186             while (ScriptCode.GetOp(ref bq1, out opcode, out pushData))
 187             {
 188                 if (pushData.Length == 0)
 189                 {
 190                     // No data, put instruction on its place
 191                     newScript.AddInstruction(opcode);
 192                 }
 193                 else if (!pushData.SequenceEqual(pattern))
 194                 {
 195                     // No match, create push operator
 196                     newScript.PushData(pushData);
 197                 }
 198                 else
 199                 {
 200                     count++; // match
 201                 }
 202             }
 203
 204             if (count > 0)
 205             {
 206                 // Replace current script if any matches were found
 207                 codeBytes = newScript.codeBytes;
 208             }
 209
 210             return count;
 211         }
 212
 213         /// <summary>
 214         /// Scan script for specific instruction and remove it if there are some matches.
 215         /// </summary>
 216         /// <param name="op">Instruction</param>
 217         /// <returns>Matches count</returns>
 218         public int RemoveInstruction(instruction op)
 219         {
 220             byte[] pushData;
 221             instruction opcode;
 222
 223             var count = 0;
 224             var newScript = new CScript();
 225             var bq1 = new ByteQueue(codeBytes);
 226
 227             while (ScriptCode.GetOp(ref bq1, out opcode, out pushData))
 228             {
 229                 if (pushData.Length != 0 && op != opcode)
 230                 {
 231                     // If instruction didn't match then push its data again
 232                     newScript.PushData(pushData);
 233                 }
 234                 else if (Enum.IsDefined(typeof(instruction), op) && op != opcode)
 235                 {
 236                     // Instruction didn't match
 237                     newScript.AddInstruction(opcode);
 238                 }
 239                 else
 240                 {
 241                     count++; // match
 242                 }
 243             }
 244
 245             if (count > 0)
 246             {
 247                 // Replace current script if any matches were found
 248                 codeBytes = newScript.codeBytes;
 249             }
 250
 251             return count;
 252         }
 253
 254         /// <summary>
 255         /// Is it true that script doesn't contain anything except push value operations?
 256         /// </summary>
 257         public bool IsPushOnly
 258         {
 259             get
 260             {
 261                 var wCodeBytes = new ByteQueue(codeBytes);
 262
 263                 instruction opcode; // Current instruction
 264                 byte[] pushArgs; // OP_PUSHDATAn argument
 265
 266                 // Scan instructions sequence
 267                 while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 268                 {
 269                     if (opcode > instruction.OP_16)
 270                     {
 271                         // We don't allow control instructions here
 272                         return false;
 273                     }
 274                 }
 275
 276                 return true;
 277             }
 278         }
 279
 280         /// <summary>
 281         /// Is it true that script doesn't contain non-canonical push operations?
 282         /// </summary>
 283         public bool HasOnlyCanonicalPushes
 284         {
 285             get
 286             {
 287                 var wCodeBytes = new ByteQueue(codeBytes);
 288
 289                 byte[] pushArgs; // OP_PUSHDATAn argument
 290                 instruction opcode; // Current instruction
 291
 292                 // Scan instructions sequence
 293                 while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 294                 {
 295                     var data = pushArgs;
 296
 297                     if (opcode < instruction.OP_PUSHDATA1 && opcode > instruction.OP_0 && (data.Length == 1 && data[0] <= 16))
 298                     {
 299                         // Could have used an OP_n code, rather than a 1-byte push.
 300                         return false;
 301                     }
 302                     if (opcode == instruction.OP_PUSHDATA1 && data.Length < (int)instruction.OP_PUSHDATA1)
 303                     {
 304                         // Could have used a normal n-byte push, rather than OP_PUSHDATA1.
 305                         return false;
 306                     }
 307                     if (opcode == instruction.OP_PUSHDATA2 && data.Length <= 0xFF)
 308                     {
 309                         // Could have used an OP_PUSHDATA1.
 310                         return false;
 311                     }
 312                     if (opcode == instruction.OP_PUSHDATA4 && data.LongLength <= 0xFFFF)
 313                     {
 314                         // Could have used an OP_PUSHDATA2.
 315                         return false;
 316                     }
 317                 }
 318
 319                 return true;
 320             }
 321         }
 322
 323         /// <summary>
 324         /// Quick test for pay-to-script-hash CScripts
 325         /// </summary>
 326         public bool IsPayToScriptHash
 327         {
 328             get
 329             {
 330                 // Sender provides redeem script hash, receiver provides signature list and redeem script
 331                 // OP_HASH160 20 [20 byte hash] OP_EQUAL
 332                 return (codeBytes.Count() == 23 &&
 333                         codeBytes[0] == (byte)instruction.OP_HASH160 &&
 334                         codeBytes[1] == 0x14 && // 20 bytes hash length prefix
 335                         codeBytes[22] == (byte)instruction.OP_EQUAL);
 336             }
 337         }
 338
 339         /// <summary>
 340         /// Quick test for pay-to-pubkeyhash CScripts
 341         /// </summary>
 342         public bool IsPayToPubKeyHash
 343         {
 344             get
 345             {
 346                 // Sender provides hash of pubkey, receiver provides signature and pubkey
 347                 // OP_DUP OP_HASH160 20 [20 byte hash] OP_EQUALVERIFY OP_CHECKSIG
 348                 return (codeBytes.Count == 25 &&
 349                         codeBytes[0] == (byte)instruction.OP_DUP &&
 350                         codeBytes[1] == (byte)instruction.OP_HASH160 &&
 351                         codeBytes[2] == 0x14 && // 20 bytes hash length prefix
 352                         codeBytes[23] == (byte)instruction.OP_EQUALVERIFY &&
 353                         codeBytes[24] == (byte)instruction.OP_CHECKSIG);
 354             }
 355         }
 356
 357         /// <summary>
 358         /// Quick test for Null destination
 359         /// </summary>
 360         public bool IsNull
 361         {
 362             get { return codeBytes.Count == 0; }
 363         }
 364
 365         /// <summary>
 366         /// Pre-version-0.6, Bitcoin always counted CHECKMULTISIGs
 367         /// as 20 sigops. With pay-to-script-hash, that changed:
 368         /// CHECKMULTISIGs serialized in scriptSigs are
 369         /// counted more accurately, assuming they are of the form
 370         ///  ... OP_N CHECKMULTISIG ...
 371         /// </summary>
 372         /// <param name="fAccurate">Legacy mode flag</param>
 373         /// <returns>Amount of sigops</returns>
 374         public int GetSigOpCount(bool fAccurate)
 375         {
 376             var wCodeBytes = new ByteQueue(codeBytes);
 377
 378             instruction opcode; // Current instruction
 379             byte[] pushArgs; // OP_PUSHDATAn argument
 380
 381             int nCount = 0;
 382             var lastOpcode = instruction.OP_INVALIDOPCODE;
 383
 384             // Scan instructions sequence
 385             while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 386             {
 387                 if (opcode == instruction.OP_CHECKSIG || opcode == instruction.OP_CHECKSIGVERIFY)
 388                 {
 389                     nCount++;
 390                 }
 391                 else if (opcode == instruction.OP_CHECKMULTISIG || opcode == instruction.OP_CHECKMULTISIGVERIFY)
 392                 {
 393                     if (fAccurate && lastOpcode >= instruction.OP_1 && lastOpcode <= instruction.OP_16)
 394                     {
 395                         nCount += ScriptCode.DecodeOP_N(lastOpcode);
 396                     }
 397                     else
 398                     {
 399                         nCount += 20;
 400                     }
 401                 }
 402             }
 403
 404             return nCount;
 405         }
 406
 407         /// <summary>
 408         /// Accurately count sigOps, including sigOps in
 409         /// pay-to-script-hash transactions
 410         /// </summary>
 411         /// <param name="scriptSig">pay-to-script-hash scriptPubKey</param>
 412         /// <returns>SigOps count</returns>
 413         public int GetSigOpCount(CScript scriptSig)
 414         {
 415             if (!IsPayToScriptHash)
 416             {
 417                 return GetSigOpCount(true);
 418             }
 419
 420             // This is a pay-to-script-hash scriptPubKey;
 421             // get the last item that the scriptSig
 422             // pushes onto the stack:
 423             ByteQueue wScriptSig = scriptSig.GetByteQUeue();
 424
 425             instruction opcode; // Current instruction
 426             byte[] pushArgs; // OP_PUSHDATAn argument
 427
 428             while (ScriptCode.GetOp(ref wScriptSig, out opcode, out pushArgs))
 429             {
 430                 if (opcode > instruction.OP_16)
 431                 {
 432                     return 0;
 433                 }
 434             }
 435
 436             /// ... and return its opcount:
 437             var subScript = new CScript(pushArgs);
 438
 439             return subScript.GetSigOpCount(true);
 440
 441         }
 442
 443         /// <summary>
 444         /// Set pay-to-pubkey destination.
 445         /// </summary>
 446         /// <param name="pubKey">Instance of CPubKey.</param>
 447         public void SetDestination(CPubKey pubKey)
 448         {
 449             codeBytes.Clear();
 450             PushData(pubKey.PublicBytes);
 451             AddInstruction(instruction.OP_CHECKSIG);
 452         }
 453
 454         /// <summary>
 455         /// Set pay-to-pubkeyhash destination
 456         /// </summary>
 457         /// <param name="ID">Public key hash</param>
 458         public void SetDestination(CKeyID ID)
 459         {
 460             codeBytes.Clear();
 461             AddInstruction(instruction.OP_DUP);
 462             AddInstruction(instruction.OP_HASH160);
 463             AddHash(ID);
 464             AddInstruction(instruction.OP_EQUALVERIFY);
 465             AddInstruction(instruction.OP_CHECKSIG);
 466         }
 467
 468         /// <summary>
 469         /// Set pay-to-scripthash destination
 470         /// </summary>
 471         /// <param name="ID">Script hash</param>
 472         public void SetDestination(CScriptID ID)
 473         {
 474             codeBytes.Clear();
 475             AddInstruction(instruction.OP_HASH160);
 476             AddHash(ID);
 477             AddInstruction(instruction.OP_EQUAL);
 478         }
 479
 480         /// <summary>
 481         /// Reset script code buffer.
 482         /// </summary>
 483         public void SetNullDestination()
 484         {
 485             codeBytes.Clear();
 486         }
 487
 488         /// <summary>
 489         /// Set multisig destination.
 490         /// </summary>
 491         /// <param name="nRequired">Amount of required signatures.</param>
 492         /// <param name="keys">Set of public keys.</param>
 493         public void SetMultiSig(int nRequired, CPubKey[] keys)
 494         {
 495             codeBytes.Clear();
 496             AddInstruction(ScriptCode.EncodeOP_N(nRequired));
 497
 498             foreach (var key in keys)
 499             {
 500                 PushData(key.PublicBytes);
 501             }
 502
 503             AddInstruction(ScriptCode.EncodeOP_N(keys.Length));
 504             AddInstruction(instruction.OP_CHECKMULTISIG);
 505         }
 506
 507         /// <summary>
 508         /// Access to script code.
 509         /// </summary>
 510         public byte[] Bytes
 511         {
 512             get { return codeBytes.ToArray(); }
 513         }
 514
 515         public CScriptID ScriptID
 516         {
 517             get { return new CScriptID(Hash160.Compute160(codeBytes.ToArray())); }
 518         }
 519
 520         /// <summary>
 521         /// Disassemble current script code
 522         /// </summary>
 523         /// <returns>Code listing</returns>
 524                 public override string ToString()
 525                 {
 526                         var sb = new StringBuilder();
 527             var wCodeBytes = new ByteQueue(codeBytes);
 528
 529             instruction opcode; // Current instruction
 530             byte[] pushArgs; // OP_PUSHDATAn argument
 531             while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 532             {
 533                 if (sb.Length != 0)
 534                 {
 535                     sb.Append(" ");
 536                 }
 537
 538                 if (0 <= opcode && opcode <= instruction.OP_PUSHDATA4)
 539                 {
 540                     sb.Append(ScriptCode.ValueString(pushArgs));
 541                 }
 542                 else
 543                 {
 544                     sb.Append(ScriptCode.GetOpName(opcode));
 545                 }
 546             }
 547
 548             return sb.ToString();
 549                 }
 550         }
 551 }