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