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 (ScriptOpcode.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 (ScriptOpcode.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             return (codeBytes.Count() == 23 &&
 246                     codeBytes[0] == (byte)opcodetype.OP_HASH160 &&
 247                     codeBytes[1] == 0x14 &&
 248                     codeBytes[22] == (byte)opcodetype.OP_EQUAL);
 249         }
 250
 251         /// <summary>
 252         /// Pre-version-0.6, Bitcoin always counted CHECKMULTISIGs
 253         /// as 20 sigops. With pay-to-script-hash, that changed:
 254         /// CHECKMULTISIGs serialized in scriptSigs are
 255         /// counted more accurately, assuming they are of the form
 256         ///  ... OP_N CHECKMULTISIG ...
 257         /// </summary>
 258         /// <param name="fAccurate">Legacy mode flag</param>
 259         /// <returns>Amount of sigops</returns>
 260         public int GetSigOpCount(bool fAccurate)
 261         {
 262             WrappedList<byte> wCodeBytes = new WrappedList<byte>(codeBytes);
 263
 264             opcodetype opcode; // Current opcode
 265             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 266
 267             int nCount = 0;
 268             opcodetype lastOpcode = opcodetype.OP_INVALIDOPCODE;
 269
 270             // Scan opcodes sequence
 271             while (ScriptOpcode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 272             {
 273                 if (opcode == opcodetype.OP_CHECKSIG || opcode == opcodetype.OP_CHECKSIGVERIFY)
 274                 {
 275                     nCount++;
 276                 }
 277                 else if (opcode == opcodetype.OP_CHECKMULTISIG || opcode == opcodetype.OP_CHECKMULTISIGVERIFY)
 278                 {
 279                     if (fAccurate && lastOpcode >= opcodetype.OP_1 && lastOpcode <= opcodetype.OP_16)
 280                     {
 281                         nCount += ScriptOpcode.DecodeOP_N(lastOpcode);
 282                     }
 283                     else
 284                     {
 285                         nCount += 20;
 286                     }
 287                 }
 288             }
 289
 290             return nCount;
 291         }
 292
 293         /// <summary>
 294         /// Accurately count sigOps, including sigOps in
 295         /// pay-to-script-hash transactions
 296         /// </summary>
 297         /// <param name="scriptSig">pay-to-script-hash scriptPubKey</param>
 298         /// <returns>SigOps count</returns>
 299         public int GetSigOpCount(CScript scriptSig)
 300         {
 301             if (!IsPayToScriptHash())
 302             {
 303                 return GetSigOpCount(true);
 304             }
 305
 306             // This is a pay-to-script-hash scriptPubKey;
 307             // get the last item that the scriptSig
 308             // pushes onto the stack:
 309             WrappedList<byte> wScriptSig = scriptSig.GetWrappedList();
 310
 311             opcodetype opcode; // Current opcode
 312             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 313
 314             while (ScriptOpcode.GetOp(ref wScriptSig, out opcode, out pushArgs))
 315             {
 316                 if (opcode > opcodetype.OP_16)
 317                 {
 318                     return 0;
 319                 }
 320             }
 321
 322             /// ... and return its opcount:
 323             CScript subScript = new CScript(pushArgs);
 324
 325             return subScript.GetSigOpCount(true);
 326
 327         }
 328
 329         public void SetDestination(CKeyID ID)
 330         {
 331             codeBytes.Clear();
 332             AddOp(opcodetype.OP_DUP);
 333             AddOp(opcodetype.OP_HASH160);
 334             AddHash(ID);
 335             AddOp(opcodetype.OP_EQUAL);
 336         }
 337
 338         public void SetDestination(CScriptID ID)
 339         {
 340             codeBytes.Clear();
 341             AddOp(opcodetype.OP_HASH160);
 342             AddHash(ID);
 343             AddOp(opcodetype.OP_EQUAL);
 344         }
 345
 346         public void SetMultiSig(int nRequired, IEnumerable<CPubKey> keys)
 347         {
 348             codeBytes.Clear();
 349             AddOp(ScriptOpcode.EncodeOP_N(nRequired));
 350
 351             foreach (CPubKey key in keys)
 352             {
 353                 PushData(key.Public.ToList());
 354             }
 355             AddOp(ScriptOpcode.EncodeOP_N(keys.Count()));
 356             AddOp(opcodetype.OP_CHECKMULTISIG);
 357         }
 358
 359         /// <summary>
 360         /// Disassemble current script code
 361         /// </summary>
 362         /// <returns>Code listing</returns>
 363                 public override string ToString()
 364                 {
 365                         StringBuilder sb = new StringBuilder();
 366             WrappedList<byte> wCodeBytes = new WrappedList<byte>(codeBytes);
 367
 368             opcodetype opcode; // Current opcode
 369             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 370             while (ScriptOpcode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 371             {
 372                 if (sb.Length != 0)
 373                 {
 374                     sb.Append(" ");
 375                 }
 376
 377                 if (0 <= opcode && opcode <= opcodetype.OP_PUSHDATA4)
 378                 {
 379                     sb.Append(ScriptOpcode.ValueString(pushArgs));
 380                 }
 381                 else
 382                 {
 383                     sb.Append(ScriptOpcode.GetOpName(opcode));
 384                 }
 385             }
 386
 387             return sb.ToString();
 388                 }
 389         }
 390 }
 391