Novacoin/CScript.cs

   1 \feffusing System;
   2 using System.Linq;
   3 using System.Text;
   4 using System.Collections.Generic;
   5
   6 namespace Novacoin
   7 {
   8     public class CScriptException : Exception
   9     {
  10         public CScriptException()
  11         {
  12         }
  13
  14         public CScriptException(string message)
  15             : base(message)
  16         {
  17         }
  18
  19         public CScriptException(string message, Exception inner)
  20             : base(message, inner)
  21         {
  22         }
  23     }
  24
  25     /// <summary>
  26     /// Representation of script code
  27     /// </summary>
  28         public class CScript
  29         {
  30         private List<byte> codeBytes;
  31
  32         /// <summary>
  33         /// Initializes an empty instance of CScript
  34         /// </summary>
  35                 public CScript ()
  36                 {
  37             codeBytes = new List<byte>();
  38                 }
  39
  40         /// <summary>
  41         /// Initializes new instance of CScript and fills it with supplied bytes
  42         /// </summary>
  43         /// <param name="bytes">Enumerator interface for byte sequence</param>
  44         public CScript(IEnumerable<byte> bytes)
  45         {
  46             codeBytes = new List<byte>(bytes);
  47         }
  48
  49         /// <summary>
  50         /// Return a new instance of WrappedList object for current code bytes
  51         /// </summary>
  52         /// <returns></returns>
  53         public WrappedList<byte> GetWrappedList()
  54         {
  55              return new WrappedList<byte>(codeBytes);
  56         }
  57
  58         /// <summary>
  59         /// Adds specified operation to opcode bytes list
  60         /// </summary>
  61         /// <param name="opcode"></param>
  62         public void AddOp(opcodetype opcode)
  63         {
  64             if (opcode < opcodetype.OP_0 || opcode > opcodetype.OP_INVALIDOPCODE)
  65             {
  66                 throw new CScriptException("CScript::AddOp() : invalid opcode");
  67             }
  68
  69             codeBytes.Add((byte)opcode);
  70         }
  71
  72         /// <summary>
  73         /// Adds hash to opcode bytes list.
  74         ///    New items are added in this format:
  75         ///    hash_length_byte hash_bytes
  76         /// </summary>
  77         /// <param name="hash">Hash160 instance</param>
  78         public void AddHash(Hash160 hash)
  79         {
  80             codeBytes.Add((byte)hash.hashSize);
  81             codeBytes.AddRange(hash.hashBytes);
  82         }
  83
  84         /// <summary>
  85         /// Adds hash to opcode bytes list.
  86         ///    New items are added in this format:
  87         ///    hash_length_byte hash_bytes
  88         /// </summary>
  89         /// <param name="hash">Hash256 instance</param>
  90         public void AddHash(Hash256 hash)
  91         {
  92             codeBytes.Add((byte)hash.hashSize);
  93             codeBytes.AddRange(hash.hashBytes);
  94         }
  95
  96         /// <summary>
  97         /// Create new OP_PUSHDATAn operator and add it to opcode bytes list
  98         /// </summary>
  99         /// <param name="dataBytes">List of data bytes</param>
 100         public void PushData(IList<byte> dataBytes)
 101         {
 102             long nCount = dataBytes.LongCount();
 103
 104             if (nCount < (int)opcodetype.OP_PUSHDATA1)
 105             {
 106                 // OP_0 and OP_FALSE
 107                 codeBytes.Add((byte)nCount);
 108             }
 109             else if (nCount < 0xff)
 110             {
 111                 // OP_PUSHDATA1 0x01 [0x5a]
 112                 codeBytes.Add((byte)opcodetype.OP_PUSHDATA1);
 113                 codeBytes.Add((byte)nCount);
 114             }
 115             else if (nCount < 0xffff)
 116             {
 117                 // OP_PUSHDATA1 0x00 0x01 [0x5a]
 118                 codeBytes.Add((byte)opcodetype.OP_PUSHDATA2);
 119
 120                 byte[] szBytes = Interop.BEBytes((ushort)nCount);
 121                 codeBytes.AddRange(szBytes);
 122             }
 123             else if (nCount < 0xffffffff)
 124             {
 125                 // OP_PUSHDATA1 0x00 0x00 0x00 0x01 [0x5a]
 126                 codeBytes.Add((byte)opcodetype.OP_PUSHDATA4);
 127
 128                 byte[] szBytes = Interop.BEBytes((uint)nCount);
 129                 codeBytes.AddRange(szBytes);
 130             }
 131
 132             // Add data bytes
 133             codeBytes.AddRange(dataBytes);
 134         }
 135
 136         /// <summary>
 137         /// Scan code bytes for pattern
 138         /// </summary>
 139         /// <param name="pattern">Pattern sequence</param>
 140         /// <returns>Matches enumerator</returns>
 141         private IEnumerable<int> FindPattern(IList<byte> pattern)
 142         {
 143             for (int i = 0; i < codeBytes.Count; i++)
 144             {
 145                 if (codeBytes.Skip(i).Take(pattern.Count).SequenceEqual(pattern))
 146                 {
 147                     yield return i;
 148                 }
 149             }
 150         }
 151
 152         /// <summary>
 153         /// Scan code bytes for pattern and remove it
 154         /// </summary>
 155         /// <param name="pattern">Pattern sequence</param>
 156         /// <returns>Matches number</returns>
 157         public int RemovePattern(IList<byte> pattern)
 158         {
 159             List<byte> resultBytes = new List<byte>(codeBytes);
 160             int count = 0;
 161             int patternLen = pattern.Count;
 162
 163             foreach (int i in FindPattern(pattern))
 164             {
 165                 resultBytes.RemoveRange(i - count * patternLen, patternLen);
 166                 count++;
 167             }
 168
 169             codeBytes = resultBytes;
 170
 171             return count;
 172         }
 173
 174         /// <summary>
 175         /// Is it true that script doesn't contain anything except push value operations?
 176         /// </summary>
 177         /// <returns>Checking result</returns>
 178         public bool IsPushonly()
 179         {
 180             WrappedList<byte> wCodeBytes = new WrappedList<byte>(codeBytes);
 181
 182             opcodetype opcode; // Current opcode
 183             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 184
 185             // Scan opcodes sequence
 186             while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 187             {
 188                 if (opcode > opcodetype.OP_16)
 189                 {
 190                     // We don't allow control opcodes here
 191                     return false;
 192                 }
 193             }
 194
 195             return true;
 196         }
 197
 198         /// <summary>
 199         /// Is it true that script doesn't contain non-canonical push operations?
 200         /// </summary>
 201         /// <returns>Checking result</returns>
 202         public bool HashOnlyCanonicalPushes()
 203         {
 204             WrappedList<byte> wCodeBytes = new WrappedList<byte>(codeBytes);
 205
 206             opcodetype opcode; // Current opcode
 207             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 208
 209             // Scan opcodes sequence
 210             while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 211             {
 212                 byte[] data = pushArgs.ToArray();
 213
 214                 if (opcode < opcodetype.OP_PUSHDATA1 && opcode > opcodetype.OP_0 && (data.Length == 1 && data[0] <= 16))
 215                 {
 216                     // Could have used an OP_n code, rather than a 1-byte push.
 217                     return false;
 218                 }
 219                 if (opcode == opcodetype.OP_PUSHDATA1 && data.Length < (int)opcodetype.OP_PUSHDATA1)
 220                 {
 221                     // Could have used a normal n-byte push, rather than OP_PUSHDATA1.
 222                     return false;
 223                 }
 224                 if (opcode == opcodetype.OP_PUSHDATA2 && data.Length <= 0xFF)
 225                 {
 226                     // Could have used an OP_PUSHDATA1.
 227                     return false;
 228                 }
 229                 if (opcode == opcodetype.OP_PUSHDATA4 && data.LongLength <= 0xFFFF)
 230                 {
 231                     // Could have used an OP_PUSHDATA2.
 232                     return false;
 233                 }
 234             }
 235
 236             return true;
 237         }
 238
 239         /// <summary>
 240         /// Quick test for pay-to-script-hash CScripts
 241         /// </summary>
 242         /// <returns>Checking result</returns>
 243         public bool IsPayToScriptHash()
 244         {
 245             // Sender provides redeem script hash, receiver provides signature list and redeem script
 246             // OP_HASH160 20 [20 byte hash] OP_EQUAL
 247             return (codeBytes.Count() == 23 &&
 248                     codeBytes[0] == (byte)opcodetype.OP_HASH160 &&
 249                     codeBytes[1] == 0x14 && // 20 bytes hash length prefix
 250                     codeBytes[22] == (byte)opcodetype.OP_EQUAL);
 251         }
 252
 253         /// <summary>
 254         /// Quick test for pay-to-pubkeyhash CScripts
 255         /// </summary>
 256         /// <returns>Checking result</returns>
 257         public bool IsPayToPubKeyHash()
 258         {
 259             // Sender provides hash of pubkey, receiver provides signature and pubkey
 260             // OP_DUP OP_HASH160 20 [20 byte hash] OP_EQUALVERIFY OP_CHECKSIG
 261
 262             return (codeBytes.Count == 25 &&
 263                     codeBytes[0] == (byte) opcodetype.OP_DUP &&
 264                     codeBytes[1] == (byte)opcodetype.OP_HASH160 &&
 265                     codeBytes[2] == 0x14 && // 20 bytes hash length prefix
 266                     codeBytes[23] == (byte)opcodetype.OP_EQUALVERIFY &&
 267                     codeBytes[24] == (byte)opcodetype.OP_CHECKSIG);
 268         }
 269
 270         /// <summary>
 271         /// Pre-version-0.6, Bitcoin always counted CHECKMULTISIGs
 272         /// as 20 sigops. With pay-to-script-hash, that changed:
 273         /// CHECKMULTISIGs serialized in scriptSigs are
 274         /// counted more accurately, assuming they are of the form
 275         ///  ... OP_N CHECKMULTISIG ...
 276         /// </summary>
 277         /// <param name="fAccurate">Legacy mode flag</param>
 278         /// <returns>Amount of sigops</returns>
 279         public int GetSigOpCount(bool fAccurate)
 280         {
 281             WrappedList<byte> wCodeBytes = new WrappedList<byte>(codeBytes);
 282
 283             opcodetype opcode; // Current opcode
 284             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 285
 286             int nCount = 0;
 287             opcodetype lastOpcode = opcodetype.OP_INVALIDOPCODE;
 288
 289             // Scan opcodes sequence
 290             while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 291             {
 292                 if (opcode == opcodetype.OP_CHECKSIG || opcode == opcodetype.OP_CHECKSIGVERIFY)
 293                 {
 294                     nCount++;
 295                 }
 296                 else if (opcode == opcodetype.OP_CHECKMULTISIG || opcode == opcodetype.OP_CHECKMULTISIGVERIFY)
 297                 {
 298                     if (fAccurate && lastOpcode >= opcodetype.OP_1 && lastOpcode <= opcodetype.OP_16)
 299                     {
 300                         nCount += ScriptCode.DecodeOP_N(lastOpcode);
 301                     }
 302                     else
 303                     {
 304                         nCount += 20;
 305                     }
 306                 }
 307             }
 308
 309             return nCount;
 310         }
 311
 312         /// <summary>
 313         /// Accurately count sigOps, including sigOps in
 314         /// pay-to-script-hash transactions
 315         /// </summary>
 316         /// <param name="scriptSig">pay-to-script-hash scriptPubKey</param>
 317         /// <returns>SigOps count</returns>
 318         public int GetSigOpCount(CScript scriptSig)
 319         {
 320             if (!IsPayToScriptHash())
 321             {
 322                 return GetSigOpCount(true);
 323             }
 324
 325             // This is a pay-to-script-hash scriptPubKey;
 326             // get the last item that the scriptSig
 327             // pushes onto the stack:
 328             WrappedList<byte> wScriptSig = scriptSig.GetWrappedList();
 329
 330             opcodetype opcode; // Current opcode
 331             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 332
 333             while (ScriptCode.GetOp(ref wScriptSig, out opcode, out pushArgs))
 334             {
 335                 if (opcode > opcodetype.OP_16)
 336                 {
 337                     return 0;
 338                 }
 339             }
 340
 341             /// ... and return its opcount:
 342             CScript subScript = new CScript(pushArgs);
 343
 344             return subScript.GetSigOpCount(true);
 345
 346         }
 347
 348         public void SetDestination(CKeyID ID)
 349         {
 350             codeBytes.Clear();
 351             AddOp(opcodetype.OP_DUP);
 352             AddOp(opcodetype.OP_HASH160);
 353             AddHash(ID);
 354             AddOp(opcodetype.OP_EQUAL);
 355         }
 356
 357         public void SetDestination(CScriptID ID)
 358         {
 359             codeBytes.Clear();
 360             AddOp(opcodetype.OP_HASH160);
 361             AddHash(ID);
 362             AddOp(opcodetype.OP_EQUAL);
 363         }
 364
 365         public void SetMultiSig(int nRequired, IEnumerable<CPubKey> keys)
 366         {
 367             codeBytes.Clear();
 368             AddOp(ScriptCode.EncodeOP_N(nRequired));
 369
 370             foreach (CPubKey key in keys)
 371             {
 372                 PushData(key.Public.ToList());
 373             }
 374             AddOp(ScriptCode.EncodeOP_N(keys.Count()));
 375             AddOp(opcodetype.OP_CHECKMULTISIG);
 376         }
 377
 378         /// <summary>
 379         /// Access to script code.
 380         /// </summary>
 381         public IEnumerable<byte> Enumerable
 382         {
 383             get { return codeBytes; }
 384         }
 385
 386         /// <summary>
 387         /// Disassemble current script code
 388         /// </summary>
 389         /// <returns>Code listing</returns>
 390                 public override string ToString()
 391                 {
 392                         StringBuilder sb = new StringBuilder();
 393             WrappedList<byte> wCodeBytes = new WrappedList<byte>(codeBytes);
 394
 395             opcodetype opcode; // Current opcode
 396             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 397             while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 398             {
 399                 if (sb.Length != 0)
 400                 {
 401                     sb.Append(" ");
 402                 }
 403
 404                 if (0 <= opcode && opcode <= opcodetype.OP_PUSHDATA4)
 405                 {
 406                     sb.Append(ScriptCode.ValueString(pushArgs));
 407                 }
 408                 else
 409                 {
 410                     sb.Append(ScriptCode.GetOpName(opcode));
 411                 }
 412             }
 413
 414             return sb.ToString();
 415                 }
 416         }
 417 }
 418