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