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(IEnumerable<byte> dataBytes)
 119         {
 120             long nCount = dataBytes.LongCount();
 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(IList<byte> pattern)
 160         {
 161             for (int i = 0; i < codeBytes.Count; i++)
 162             {
 163                 if (codeBytes.Skip(i).Take(pattern.Count).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(IList<byte> pattern)
 176         {
 177             List<byte> resultBytes = new List<byte>(codeBytes);
 178             int count = 0;
 179             int patternLen = pattern.Count;
 180
 181             foreach (int i in FindPattern(pattern))
 182             {
 183                 resultBytes.RemoveRange(i - count * patternLen, patternLen);
 184                 count++;
 185             }
 186
 187             codeBytes = resultBytes;
 188
 189             return count;
 190         }
 191
 192         /// <summary>
 193         /// Is it true that script doesn't contain anything except push value operations?
 194         /// </summary>
 195         public bool IsPushOnly
 196         {
 197             get
 198             {
 199                 ByteQueue wCodeBytes = new ByteQueue(codeBytes);
 200
 201                 instruction opcode; // Current opcode
 202                 IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 203
 204                 // Scan opcodes sequence
 205                 while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 206                 {
 207                     if (opcode > instruction.OP_16)
 208                     {
 209                         // We don't allow control opcodes here
 210                         return false;
 211                     }
 212                 }
 213
 214                 return true;
 215             }
 216         }
 217
 218         /// <summary>
 219         /// Is it true that script doesn't contain non-canonical push operations?
 220         /// </summary>
 221         public bool HasOnlyCanonicalPushes
 222         {
 223             get
 224             {
 225                 ByteQueue wCodeBytes = new ByteQueue(codeBytes);
 226
 227                 instruction opcode; // Current opcode
 228                 IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 229
 230                 // Scan opcodes sequence
 231                 while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 232                 {
 233                     byte[] data = pushArgs.ToArray();
 234
 235                     if (opcode < instruction.OP_PUSHDATA1 && opcode > instruction.OP_0 && (data.Length == 1 && data[0] <= 16))
 236                     {
 237                         // Could have used an OP_n code, rather than a 1-byte push.
 238                         return false;
 239                     }
 240                     if (opcode == instruction.OP_PUSHDATA1 && data.Length < (int)instruction.OP_PUSHDATA1)
 241                     {
 242                         // Could have used a normal n-byte push, rather than OP_PUSHDATA1.
 243                         return false;
 244                     }
 245                     if (opcode == instruction.OP_PUSHDATA2 && data.Length <= 0xFF)
 246                     {
 247                         // Could have used an OP_PUSHDATA1.
 248                         return false;
 249                     }
 250                     if (opcode == instruction.OP_PUSHDATA4 && data.LongLength <= 0xFFFF)
 251                     {
 252                         // Could have used an OP_PUSHDATA2.
 253                         return false;
 254                     }
 255                 }
 256
 257                 return true;
 258             }
 259         }
 260
 261         /// <summary>
 262         /// Quick test for pay-to-script-hash CScripts
 263         /// </summary>
 264         public bool IsPayToScriptHash
 265         {
 266             get
 267             {
 268                 // Sender provides redeem script hash, receiver provides signature list and redeem script
 269                 // OP_HASH160 20 [20 byte hash] OP_EQUAL
 270                 return (codeBytes.Count() == 23 &&
 271                         codeBytes[0] == (byte)instruction.OP_HASH160 &&
 272                         codeBytes[1] == 0x14 && // 20 bytes hash length prefix
 273                         codeBytes[22] == (byte)instruction.OP_EQUAL);
 274             }
 275         }
 276
 277         /// <summary>
 278         /// Quick test for pay-to-pubkeyhash CScripts
 279         /// </summary>
 280         public bool IsPayToPubKeyHash
 281         {
 282             get
 283             {
 284                 // Sender provides hash of pubkey, receiver provides signature and pubkey
 285                 // OP_DUP OP_HASH160 20 [20 byte hash] OP_EQUALVERIFY OP_CHECKSIG
 286                 return (codeBytes.Count == 25 &&
 287                         codeBytes[0] == (byte)instruction.OP_DUP &&
 288                         codeBytes[1] == (byte)instruction.OP_HASH160 &&
 289                         codeBytes[2] == 0x14 && // 20 bytes hash length prefix
 290                         codeBytes[23] == (byte)instruction.OP_EQUALVERIFY &&
 291                         codeBytes[24] == (byte)instruction.OP_CHECKSIG);
 292             }
 293         }
 294
 295         /// <summary>
 296         /// Quick test for Null destination
 297         /// </summary>
 298         public bool IsNull
 299         {
 300             get { return codeBytes.Count == 0; }
 301         }
 302
 303         /// <summary>
 304         /// Pre-version-0.6, Bitcoin always counted CHECKMULTISIGs
 305         /// as 20 sigops. With pay-to-script-hash, that changed:
 306         /// CHECKMULTISIGs serialized in scriptSigs are
 307         /// counted more accurately, assuming they are of the form
 308         ///  ... OP_N CHECKMULTISIG ...
 309         /// </summary>
 310         /// <param name="fAccurate">Legacy mode flag</param>
 311         /// <returns>Amount of sigops</returns>
 312         public int GetSigOpCount(bool fAccurate)
 313         {
 314             ByteQueue wCodeBytes = new ByteQueue(codeBytes);
 315
 316             instruction opcode; // Current opcode
 317             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 318
 319             int nCount = 0;
 320             instruction lastOpcode = instruction.OP_INVALIDOPCODE;
 321
 322             // Scan opcodes sequence
 323             while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 324             {
 325                 if (opcode == instruction.OP_CHECKSIG || opcode == instruction.OP_CHECKSIGVERIFY)
 326                 {
 327                     nCount++;
 328                 }
 329                 else if (opcode == instruction.OP_CHECKMULTISIG || opcode == instruction.OP_CHECKMULTISIGVERIFY)
 330                 {
 331                     if (fAccurate && lastOpcode >= instruction.OP_1 && lastOpcode <= instruction.OP_16)
 332                     {
 333                         nCount += ScriptCode.DecodeOP_N(lastOpcode);
 334                     }
 335                     else
 336                     {
 337                         nCount += 20;
 338                     }
 339                 }
 340             }
 341
 342             return nCount;
 343         }
 344
 345         /// <summary>
 346         /// Accurately count sigOps, including sigOps in
 347         /// pay-to-script-hash transactions
 348         /// </summary>
 349         /// <param name="scriptSig">pay-to-script-hash scriptPubKey</param>
 350         /// <returns>SigOps count</returns>
 351         public int GetSigOpCount(CScript scriptSig)
 352         {
 353             if (!IsPayToScriptHash)
 354             {
 355                 return GetSigOpCount(true);
 356             }
 357
 358             // This is a pay-to-script-hash scriptPubKey;
 359             // get the last item that the scriptSig
 360             // pushes onto the stack:
 361             ByteQueue wScriptSig = scriptSig.GetByteQUeue();
 362
 363             instruction opcode; // Current opcode
 364             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 365
 366             while (ScriptCode.GetOp(ref wScriptSig, out opcode, out pushArgs))
 367             {
 368                 if (opcode > instruction.OP_16)
 369                 {
 370                     return 0;
 371                 }
 372             }
 373
 374             /// ... and return its opcount:
 375             CScript subScript = new CScript(pushArgs);
 376
 377             return subScript.GetSigOpCount(true);
 378
 379         }
 380
 381         /// <summary>
 382         /// Set pay-to-pubkey destination.
 383         /// </summary>
 384         /// <param name="pubKey">Instance of CPubKey.</param>
 385         public void SetDestination(CPubKey pubKey)
 386         {
 387             codeBytes.Clear();
 388             PushData(pubKey.PublicBytes);
 389             AddOp(instruction.OP_CHECKSIG);
 390         }
 391
 392         /// <summary>
 393         /// Set pay-to-pubkeyhash destination
 394         /// </summary>
 395         /// <param name="ID">Public key hash</param>
 396         public void SetDestination(CKeyID ID)
 397         {
 398             codeBytes.Clear();
 399             AddOp(instruction.OP_DUP);
 400             AddOp(instruction.OP_HASH160);
 401             AddHash(ID);
 402             AddOp(instruction.OP_EQUALVERIFY);
 403             AddOp(instruction.OP_CHECKSIG);
 404         }
 405
 406         /// <summary>
 407         /// Set pay-to-scripthash destination
 408         /// </summary>
 409         /// <param name="ID">Script hash</param>
 410         public void SetDestination(CScriptID ID)
 411         {
 412             codeBytes.Clear();
 413             AddOp(instruction.OP_HASH160);
 414             AddHash(ID);
 415             AddOp(instruction.OP_EQUAL);
 416         }
 417
 418         /// <summary>
 419         /// Reset script code buffer.
 420         /// </summary>
 421         public void SetNullDestination()
 422         {
 423             codeBytes.Clear();
 424         }
 425
 426         /// <summary>
 427         /// Set multisig destination.
 428         /// </summary>
 429         /// <param name="nRequired">Amount of required signatures.</param>
 430         /// <param name="keys">Set of public keys.</param>
 431         public void SetMultiSig(int nRequired, IEnumerable<CPubKey> keys)
 432         {
 433             codeBytes.Clear();
 434             AddOp(ScriptCode.EncodeOP_N(nRequired));
 435
 436             foreach (CPubKey key in keys)
 437             {
 438                 PushData(key.PublicBytes.ToList());
 439             }
 440
 441             AddOp(ScriptCode.EncodeOP_N(keys.Count()));
 442             AddOp(instruction.OP_CHECKMULTISIG);
 443         }
 444
 445         /// <summary>
 446         /// Access to script code.
 447         /// </summary>
 448         public IEnumerable<byte> Bytes
 449         {
 450             get { return codeBytes; }
 451         }
 452
 453         public CScriptID ScriptID
 454         {
 455             get { return new CScriptID(Hash160.Compute160(codeBytes)); }
 456         }
 457
 458         /// <summary>
 459         /// Disassemble current script code
 460         /// </summary>
 461         /// <returns>Code listing</returns>
 462                 public override string ToString()
 463                 {
 464                         StringBuilder sb = new StringBuilder();
 465             ByteQueue wCodeBytes = new ByteQueue(codeBytes);
 466
 467             instruction opcode; // Current opcode
 468             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 469             while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 470             {
 471                 if (sb.Length != 0)
 472                 {
 473                     sb.Append(" ");
 474                 }
 475
 476                 if (0 <= opcode && opcode <= instruction.OP_PUSHDATA4)
 477                 {
 478                     sb.Append(ScriptCode.ValueString(pushArgs));
 479                 }
 480                 else
 481                 {
 482                     sb.Append(ScriptCode.GetOpName(opcode));
 483                 }
 484             }
 485
 486             return sb.ToString();
 487                 }
 488         }
 489 }
 490