Novacoin/ScriptCode.cs

   1 using System;
   2 using System.Collections.Generic;
   3 using System.Linq;
   4 using System.Text;
   5
   6 namespace Novacoin
   7 {
   8     /// <summary>
   9     /// Script opcodes
  10     /// </summary>
  11     public enum opcodetype
  12     {
  13         // push value
  14         OP_0 = 0x00,
  15         OP_FALSE = OP_0,
  16         OP_PUSHDATA1 = 0x4c,
  17         OP_PUSHDATA2 = 0x4d,
  18         OP_PUSHDATA4 = 0x4e,
  19         OP_1NEGATE = 0x4f,
  20         OP_RESERVED = 0x50,
  21         OP_1 = 0x51,
  22         OP_TRUE = OP_1,
  23         OP_2 = 0x52,
  24         OP_3 = 0x53,
  25         OP_4 = 0x54,
  26         OP_5 = 0x55,
  27         OP_6 = 0x56,
  28         OP_7 = 0x57,
  29         OP_8 = 0x58,
  30         OP_9 = 0x59,
  31         OP_10 = 0x5a,
  32         OP_11 = 0x5b,
  33         OP_12 = 0x5c,
  34         OP_13 = 0x5d,
  35         OP_14 = 0x5e,
  36         OP_15 = 0x5f,
  37         OP_16 = 0x60,
  38
  39         // control
  40         OP_NOP = 0x61,
  41         OP_VER = 0x62,
  42         OP_IF = 0x63,
  43         OP_NOTIF = 0x64,
  44         OP_VERIF = 0x65,
  45         OP_VERNOTIF = 0x66,
  46         OP_ELSE = 0x67,
  47         OP_ENDIF = 0x68,
  48         OP_VERIFY = 0x69,
  49         OP_RETURN = 0x6a,
  50
  51         // stack ops
  52         OP_TOALTSTACK = 0x6b,
  53         OP_FROMALTSTACK = 0x6c,
  54         OP_2DROP = 0x6d,
  55         OP_2DUP = 0x6e,
  56         OP_3DUP = 0x6f,
  57         OP_2OVER = 0x70,
  58         OP_2ROT = 0x71,
  59         OP_2SWAP = 0x72,
  60         OP_IFDUP = 0x73,
  61         OP_DEPTH = 0x74,
  62         OP_DROP = 0x75,
  63         OP_DUP = 0x76,
  64         OP_NIP = 0x77,
  65         OP_OVER = 0x78,
  66         OP_PICK = 0x79,
  67         OP_ROLL = 0x7a,
  68         OP_ROT = 0x7b,
  69         OP_SWAP = 0x7c,
  70         OP_TUCK = 0x7d,
  71
  72         // splice ops
  73         OP_CAT = 0x7e,
  74         OP_SUBSTR = 0x7f,
  75         OP_LEFT = 0x80,
  76         OP_RIGHT = 0x81,
  77         OP_SIZE = 0x82,
  78
  79         // bit logic
  80         OP_INVERT = 0x83,
  81         OP_AND = 0x84,
  82         OP_OR = 0x85,
  83         OP_XOR = 0x86,
  84         OP_EQUAL = 0x87,
  85         OP_EQUALVERIFY = 0x88,
  86         OP_RESERVED1 = 0x89,
  87         OP_RESERVED2 = 0x8a,
  88
  89         // numeric
  90         OP_1ADD = 0x8b,
  91         OP_1SUB = 0x8c,
  92         OP_2MUL = 0x8d,
  93         OP_2DIV = 0x8e,
  94         OP_NEGATE = 0x8f,
  95         OP_ABS = 0x90,
  96         OP_NOT = 0x91,
  97         OP_0NOTEQUAL = 0x92,
  98
  99         OP_ADD = 0x93,
 100         OP_SUB = 0x94,
 101         OP_MUL = 0x95,
 102         OP_DIV = 0x96,
 103         OP_MOD = 0x97,
 104         OP_LSHIFT = 0x98,
 105         OP_RSHIFT = 0x99,
 106
 107         OP_BOOLAND = 0x9a,
 108         OP_BOOLOR = 0x9b,
 109         OP_NUMEQUAL = 0x9c,
 110         OP_NUMEQUALVERIFY = 0x9d,
 111         OP_NUMNOTEQUAL = 0x9e,
 112         OP_LESSTHAN = 0x9f,
 113         OP_GREATERTHAN = 0xa0,
 114         OP_LESSTHANOREQUAL = 0xa1,
 115         OP_GREATERTHANOREQUAL = 0xa2,
 116         OP_MIN = 0xa3,
 117         OP_MAX = 0xa4,
 118
 119         OP_WITHIN = 0xa5,
 120
 121         // crypto
 122         OP_RIPEMD160 = 0xa6,
 123         OP_SHA1 = 0xa7,
 124         OP_SHA256 = 0xa8,
 125         OP_HASH160 = 0xa9,
 126         OP_HASH256 = 0xaa,
 127         OP_CODESEPARATOR = 0xab,
 128         OP_CHECKSIG = 0xac,
 129         OP_CHECKSIGVERIFY = 0xad,
 130         OP_CHECKMULTISIG = 0xae,
 131         OP_CHECKMULTISIGVERIFY = 0xaf,
 132
 133         // expansion
 134         OP_NOP1 = 0xb0,
 135         OP_NOP2 = 0xb1,
 136         OP_NOP3 = 0xb2,
 137         OP_NOP4 = 0xb3,
 138         OP_NOP5 = 0xb4,
 139         OP_NOP6 = 0xb5,
 140         OP_NOP7 = 0xb6,
 141         OP_NOP8 = 0xb7,
 142         OP_NOP9 = 0xb8,
 143         OP_NOP10 = 0xb9,
 144
 145         // template matching params
 146         OP_SMALLDATA = 0xf9,
 147         OP_SMALLINTEGER = 0xfa,
 148         OP_PUBKEYS = 0xfb,
 149         OP_PUBKEYHASH = 0xfd,
 150         OP_PUBKEY = 0xfe,
 151
 152         OP_INVALIDOPCODE = 0xff,
 153     };
 154
 155     /// <summary>
 156     /// Transaction output types.
 157     /// </summary>
 158     public enum txnouttype
 159     {
 160         TX_NONSTANDARD,
 161
 162         // 'standard' transaction types:
 163         TX_PUBKEY,
 164         TX_PUBKEYHASH,
 165         TX_SCRIPTHASH,
 166         TX_MULTISIG,
 167         TX_NULL_DATA,
 168     };
 169
 170     public static class ScriptCode
 171     {
 172
 173         /// <summary>
 174         /// Get the name of supplied opcode
 175         /// </summary>
 176         /// <param name="opcode">Opcode</param>
 177         /// <returns>Opcode name</returns>
 178         public static string GetOpName(opcodetype opcode)
 179         {
 180             switch (opcode)
 181             {
 182                 // push value
 183                 case opcodetype.OP_0:
 184                     return "0";
 185                 case opcodetype.OP_PUSHDATA1:
 186                     return "OP_PUSHDATA1";
 187                 case opcodetype.OP_PUSHDATA2:
 188                     return "OP_PUSHDATA2";
 189                 case opcodetype.OP_PUSHDATA4:
 190                     return "OP_PUSHDATA4";
 191                 case opcodetype.OP_1NEGATE:
 192                     return "-1";
 193                 case opcodetype.OP_RESERVED:
 194                     return "OP_RESERVED";
 195                 case opcodetype.OP_1:
 196                     return "1";
 197                 case opcodetype.OP_2:
 198                     return "2";
 199                 case opcodetype.OP_3:
 200                     return "3";
 201                 case opcodetype.OP_4:
 202                     return "4";
 203                 case opcodetype.OP_5:
 204                     return "5";
 205                 case opcodetype.OP_6:
 206                     return "6";
 207                 case opcodetype.OP_7:
 208                     return "7";
 209                 case opcodetype.OP_8:
 210                     return "8";
 211                 case opcodetype.OP_9:
 212                     return "9";
 213                 case opcodetype.OP_10:
 214                     return "10";
 215                 case opcodetype.OP_11:
 216                     return "11";
 217                 case opcodetype.OP_12:
 218                     return "12";
 219                 case opcodetype.OP_13:
 220                     return "13";
 221                 case opcodetype.OP_14:
 222                     return "14";
 223                 case opcodetype.OP_15:
 224                     return "15";
 225                 case opcodetype.OP_16:
 226                     return "16";
 227
 228                 // control
 229                 case opcodetype.OP_NOP:
 230                     return "OP_NOP";
 231                 case opcodetype.OP_VER:
 232                     return "OP_VER";
 233                 case opcodetype.OP_IF:
 234                     return "OP_IF";
 235                 case opcodetype.OP_NOTIF:
 236                     return "OP_NOTIF";
 237                 case opcodetype.OP_VERIF:
 238                     return "OP_VERIF";
 239                 case opcodetype.OP_VERNOTIF:
 240                     return "OP_VERNOTIF";
 241                 case opcodetype.OP_ELSE:
 242                     return "OP_ELSE";
 243                 case opcodetype.OP_ENDIF:
 244                     return "OP_ENDIF";
 245                 case opcodetype.OP_VERIFY:
 246                     return "OP_VERIFY";
 247                 case opcodetype.OP_RETURN:
 248                     return "OP_RETURN";
 249
 250                 // stack ops
 251                 case opcodetype.OP_TOALTSTACK:
 252                     return "OP_TOALTSTACK";
 253                 case opcodetype.OP_FROMALTSTACK:
 254                     return "OP_FROMALTSTACK";
 255                 case opcodetype.OP_2DROP:
 256                     return "OP_2DROP";
 257                 case opcodetype.OP_2DUP:
 258                     return "OP_2DUP";
 259                 case opcodetype.OP_3DUP:
 260                     return "OP_3DUP";
 261                 case opcodetype.OP_2OVER:
 262                     return "OP_2OVER";
 263                 case opcodetype.OP_2ROT:
 264                     return "OP_2ROT";
 265                 case opcodetype.OP_2SWAP:
 266                     return "OP_2SWAP";
 267                 case opcodetype.OP_IFDUP:
 268                     return "OP_IFDUP";
 269                 case opcodetype.OP_DEPTH:
 270                     return "OP_DEPTH";
 271                 case opcodetype.OP_DROP:
 272                     return "OP_DROP";
 273                 case opcodetype.OP_DUP:
 274                     return "OP_DUP";
 275                 case opcodetype.OP_NIP:
 276                     return "OP_NIP";
 277                 case opcodetype.OP_OVER:
 278                     return "OP_OVER";
 279                 case opcodetype.OP_PICK:
 280                     return "OP_PICK";
 281                 case opcodetype.OP_ROLL:
 282                     return "OP_ROLL";
 283                 case opcodetype.OP_ROT:
 284                     return "OP_ROT";
 285                 case opcodetype.OP_SWAP:
 286                     return "OP_SWAP";
 287                 case opcodetype.OP_TUCK:
 288                     return "OP_TUCK";
 289
 290                 // splice ops
 291                 case opcodetype.OP_CAT:
 292                     return "OP_CAT";
 293                 case opcodetype.OP_SUBSTR:
 294                     return "OP_SUBSTR";
 295                 case opcodetype.OP_LEFT:
 296                     return "OP_LEFT";
 297                 case opcodetype.OP_RIGHT:
 298                     return "OP_RIGHT";
 299                 case opcodetype.OP_SIZE:
 300                     return "OP_SIZE";
 301
 302                 // bit logic
 303                 case opcodetype.OP_INVERT:
 304                     return "OP_INVERT";
 305                 case opcodetype.OP_AND:
 306                     return "OP_AND";
 307                 case opcodetype.OP_OR:
 308                     return "OP_OR";
 309                 case opcodetype.OP_XOR:
 310                     return "OP_XOR";
 311                 case opcodetype.OP_EQUAL:
 312                     return "OP_EQUAL";
 313                 case opcodetype.OP_EQUALVERIFY:
 314                     return "OP_EQUALVERIFY";
 315                 case opcodetype.OP_RESERVED1:
 316                     return "OP_RESERVED1";
 317                 case opcodetype.OP_RESERVED2:
 318                     return "OP_RESERVED2";
 319
 320                 // numeric
 321                 case opcodetype.OP_1ADD:
 322                     return "OP_1ADD";
 323                 case opcodetype.OP_1SUB:
 324                     return "OP_1SUB";
 325                 case opcodetype.OP_2MUL:
 326                     return "OP_2MUL";
 327                 case opcodetype.OP_2DIV:
 328                     return "OP_2DIV";
 329                 case opcodetype.OP_NEGATE:
 330                     return "OP_NEGATE";
 331                 case opcodetype.OP_ABS:
 332                     return "OP_ABS";
 333                 case opcodetype.OP_NOT:
 334                     return "OP_NOT";
 335                 case opcodetype.OP_0NOTEQUAL:
 336                     return "OP_0NOTEQUAL";
 337                 case opcodetype.OP_ADD:
 338                     return "OP_ADD";
 339                 case opcodetype.OP_SUB:
 340                     return "OP_SUB";
 341                 case opcodetype.OP_MUL:
 342                     return "OP_MUL";
 343                 case opcodetype.OP_DIV:
 344                     return "OP_DIV";
 345                 case opcodetype.OP_MOD:
 346                     return "OP_MOD";
 347                 case opcodetype.OP_LSHIFT:
 348                     return "OP_LSHIFT";
 349                 case opcodetype.OP_RSHIFT:
 350                     return "OP_RSHIFT";
 351                 case opcodetype.OP_BOOLAND:
 352                     return "OP_BOOLAND";
 353                 case opcodetype.OP_BOOLOR:
 354                     return "OP_BOOLOR";
 355                 case opcodetype.OP_NUMEQUAL:
 356                     return "OP_NUMEQUAL";
 357                 case opcodetype.OP_NUMEQUALVERIFY:
 358                     return "OP_NUMEQUALVERIFY";
 359                 case opcodetype.OP_NUMNOTEQUAL:
 360                     return "OP_NUMNOTEQUAL";
 361                 case opcodetype.OP_LESSTHAN:
 362                     return "OP_LESSTHAN";
 363                 case opcodetype.OP_GREATERTHAN:
 364                     return "OP_GREATERTHAN";
 365                 case opcodetype.OP_LESSTHANOREQUAL:
 366                     return "OP_LESSTHANOREQUAL";
 367                 case opcodetype.OP_GREATERTHANOREQUAL:
 368                     return "OP_GREATERTHANOREQUAL";
 369                 case opcodetype.OP_MIN:
 370                     return "OP_MIN";
 371                 case opcodetype.OP_MAX:
 372                     return "OP_MAX";
 373                 case opcodetype.OP_WITHIN:
 374                     return "OP_WITHIN";
 375
 376                 // crypto
 377                 case opcodetype.OP_RIPEMD160:
 378                     return "OP_RIPEMD160";
 379                 case opcodetype.OP_SHA1:
 380                     return "OP_SHA1";
 381                 case opcodetype.OP_SHA256:
 382                     return "OP_SHA256";
 383                 case opcodetype.OP_HASH160:
 384                     return "OP_HASH160";
 385                 case opcodetype.OP_HASH256:
 386                     return "OP_HASH256";
 387                 case opcodetype.OP_CODESEPARATOR:
 388                     return "OP_CODESEPARATOR";
 389                 case opcodetype.OP_CHECKSIG:
 390                     return "OP_CHECKSIG";
 391                 case opcodetype.OP_CHECKSIGVERIFY:
 392                     return "OP_CHECKSIGVERIFY";
 393                 case opcodetype.OP_CHECKMULTISIG:
 394                     return "OP_CHECKMULTISIG";
 395                 case opcodetype.OP_CHECKMULTISIGVERIFY:
 396                     return "OP_CHECKMULTISIGVERIFY";
 397
 398                 // expansion
 399                 case opcodetype.OP_NOP1:
 400                     return "OP_NOP1";
 401                 case opcodetype.OP_NOP2:
 402                     return "OP_NOP2";
 403                 case opcodetype.OP_NOP3:
 404                     return "OP_NOP3";
 405                 case opcodetype.OP_NOP4:
 406                     return "OP_NOP4";
 407                 case opcodetype.OP_NOP5:
 408                     return "OP_NOP5";
 409                 case opcodetype.OP_NOP6:
 410                     return "OP_NOP6";
 411                 case opcodetype.OP_NOP7:
 412                     return "OP_NOP7";
 413                 case opcodetype.OP_NOP8:
 414                     return "OP_NOP8";
 415                 case opcodetype.OP_NOP9:
 416                     return "OP_NOP9";
 417                 case opcodetype.OP_NOP10:
 418                     return "OP_NOP10";
 419
 420                 // template matching params
 421                 case opcodetype.OP_PUBKEYHASH:
 422                     return "OP_PUBKEYHASH";
 423                 case opcodetype.OP_PUBKEY:
 424                     return "OP_PUBKEY";
 425                 case opcodetype.OP_SMALLDATA:
 426                     return "OP_SMALLDATA";
 427
 428                 case opcodetype.OP_INVALIDOPCODE:
 429                     return "OP_INVALIDOPCODE";
 430                 default:
 431                     return "OP_UNKNOWN";
 432             }
 433         }
 434
 435         /// <summary>
 436         /// Get next opcode from passed list of bytes and extract push arguments if there are some.
 437         /// </summary>
 438         /// <param name="codeBytes">WrappedList reference.</param>
 439         /// <param name="opcodeRet">Found opcode.</param>
 440         /// <param name="bytesRet">IEnumerable out param which is used to get the push arguments.</param>
 441         /// <returns>Result of operation</returns>
 442         public static bool GetOp(ref WrappedList<byte> codeBytes, out opcodetype opcodeRet, out IEnumerable<byte> bytesRet)
 443         {
 444             bytesRet = new List<byte>();
 445             opcodeRet = opcodetype.OP_INVALIDOPCODE;
 446
 447             opcodetype opcode;
 448
 449             try
 450             {
 451                 // Read instruction
 452                 opcode = (opcodetype)codeBytes.GetItem();
 453             }
 454             catch (WrappedListException)
 455             {
 456                 // No instruction found there
 457                 return false;
 458             }
 459
 460             // Immediate operand
 461             if (opcode <= opcodetype.OP_PUSHDATA4)
 462             {
 463                 byte[] szBytes = new byte[4] { 0, 0, 0, 0 }; // Zero length
 464
 465                 try
 466                 {
 467                     if (opcode < opcodetype.OP_PUSHDATA1)
 468                     {
 469                         // Zero value opcodes (OP_0, OP_FALSE)
 470                         szBytes[3] = (byte)opcode;
 471                     }
 472                     else if (opcode == opcodetype.OP_PUSHDATA1)
 473                     {
 474                         // The next byte contains the number of bytes to be pushed onto the stack,
 475                         //    i.e. you have something like OP_PUSHDATA1 0x01 [0x5a]
 476                         szBytes[3] = (byte)codeBytes.GetItem();
 477                     }
 478                     else if (opcode == opcodetype.OP_PUSHDATA2)
 479                     {
 480                         // The next two bytes contain the number of bytes to be pushed onto the stack,
 481                         //    i.e. now your operation will seem like this: OP_PUSHDATA2 0x00 0x01 [0x5a]
 482                         codeBytes.GetItems(2).CopyTo(szBytes, 2);
 483                     }
 484                     else if (opcode == opcodetype.OP_PUSHDATA4)
 485                     {
 486                         // The next four bytes contain the number of bytes to be pushed onto the stack,
 487                         //   OP_PUSHDATA4 0x00 0x00 0x00 0x01 [0x5a]
 488                         szBytes = codeBytes.GetItems(4);
 489                     }
 490                 }
 491                 catch (WrappedListException)
 492                 {
 493                     // Unable to read operand length
 494                     return false;
 495                 }
 496
 497                 int nSize = (int)Interop.BEBytesToUInt32(szBytes);
 498
 499                 if (nSize > 0)
 500                 {
 501                     // If nSize is greater than zero then there is some data available
 502                     try
 503                     {
 504                         // Read found number of bytes into list of OP_PUSHDATAn arguments.
 505                         bytesRet = codeBytes.GetEnumerableItems(nSize);
 506                     }
 507                     catch (WrappedListException)
 508                     {
 509                         // Unable to read data
 510                         return false;
 511                     }
 512                 }
 513             }
 514
 515             opcodeRet = opcode;
 516
 517             return true;
 518         }
 519
 520         /// <summary>
 521         /// Convert value bytes into readable representation.
 522         ///
 523         /// If list lengh is equal or lesser than 4 bytes then bytes are interpreted as integer value. Otherwise you will get hex representation of supplied data.
 524         /// </summary>
 525         /// <param name="bytes">Collection of value bytes.</param>
 526         /// <returns>Formatted value.</returns>
 527         public static string ValueString(IEnumerable<byte> bytes)
 528         {
 529             StringBuilder sb = new StringBuilder();
 530
 531             if (bytes.Count() <= 4)
 532             {
 533                 byte[] valueBytes = new byte[4] { 0, 0, 0, 0 };
 534                 bytes.ToArray().CopyTo(valueBytes, valueBytes.Length - bytes.Count());
 535
 536                 sb.Append(Interop.BEBytesToUInt32(valueBytes));
 537             }
 538             else
 539             {
 540                 return Interop.ToHex(bytes);
 541             }
 542
 543             return sb.ToString();
 544         }
 545
 546         /// <summary>
 547         /// Convert list of stack items into human readable representation.
 548         /// </summary>
 549         /// <param name="stackList">List of stack items.</param>
 550         /// <returns>Formatted value.</returns>
 551         public static string StackString(IList<IList<byte>> stackList)
 552         {
 553             StringBuilder sb = new StringBuilder();
 554             foreach (IList<byte> bytesList in stackList)
 555             {
 556                 sb.Append(ValueString(bytesList));
 557             }
 558
 559             return sb.ToString();
 560         }
 561
 562         /// <summary>
 563         /// Decode small integer
 564         /// </summary>
 565         /// <param name="opcode">Small integer opcode (OP_0 - OP_16)</param>
 566         /// <returns>Small integer</returns>
 567         public static int DecodeOP_N(opcodetype opcode)
 568         {
 569             if (opcode == opcodetype.OP_0)
 570                 return 0;
 571
 572             // Only OP_n opcodes are supported, throw exception otherwise.
 573             if (opcode < opcodetype.OP_1 || opcode > opcodetype.OP_16)
 574                 throw new Exception("Invalid small integer opcode.");
 575             return (int)opcode - (int)(opcodetype.OP_1 - 1);
 576         }
 577
 578         /// <summary>
 579         /// Converts small integer into opcode
 580         /// </summary>
 581         /// <param name="n">Small integer from the range of 0 up to 16.</param>
 582         /// <returns>Corresponding opcode.</returns>
 583         public static opcodetype EncodeOP_N(int n)
 584         {
 585             // The n value must be in the range of 0 to 16.
 586             if (n < 0 || n > 16)
 587                 throw new Exception("Invalid small integer value.");
 588             if (n == 0)
 589                 return opcodetype.OP_0;
 590             return (opcodetype)(opcodetype.OP_1 + n - 1);
 591         }
 592
 593         public static int ScriptSigArgsExpected(txnouttype t, IList<IEnumerable<byte>> solutions)
 594         {
 595             switch (t)
 596             {
 597                 case txnouttype.TX_NONSTANDARD:
 598                     return -1;
 599                 case txnouttype.TX_NULL_DATA:
 600                     return 1;
 601                 case txnouttype.TX_PUBKEY:
 602                     return 1;
 603                 case txnouttype.TX_PUBKEYHASH:
 604                     return 2;
 605                 case txnouttype.TX_MULTISIG:
 606                     if (solutions.Count() < 1 || solutions.First().Count() < 1)
 607                         return -1;
 608                     return solutions.First().First() + 1;
 609                 case txnouttype.TX_SCRIPTHASH:
 610                     return 1; // doesn't include args needed by the script
 611             }
 612             return -1;
 613         }
 614
 615
 616         public static bool IsStandard(CScript scriptPubKey, out txnouttype whichType)
 617         {
 618             IList<IEnumerable<byte>> solutions = new List<IEnumerable<byte>>();
 619
 620             if (!Solver(scriptPubKey, out whichType, out solutions))
 621             {
 622                 // No solutions found
 623                 return false;
 624             }
 625
 626             if (whichType == txnouttype.TX_MULTISIG)
 627             {
 628                 byte m = solutions.First().First();
 629                 byte n = solutions.Last().First();
 630
 631                 // Support up to x-of-3 multisig txns as standard
 632                 if (n < 1 || n > 3)
 633                 {
 634                     return false;
 635                 }
 636                 if (m < 1 || m > n)
 637                 {
 638                     return false;
 639                 }
 640             }
 641
 642             return whichType != txnouttype.TX_NONSTANDARD;
 643         }
 644
 645         /// <summary>
 646         /// Return public keys or hashes from scriptPubKey, for 'standard' transaction types.
 647         /// </summary>
 648         /// <param name="scriptPubKey">CScript instance</param>
 649         /// <param name="typeRet">Output type</param>
 650         /// <param name="solutions">Set of solutions</param>
 651         /// <returns>Result</returns>
 652         public static bool Solver(CScript scriptPubKey, out txnouttype typeRet, out IList<IEnumerable<byte>> solutions)
 653         {
 654             solutions = new List<IEnumerable<byte>>();
 655
 656             // There are shortcuts for pay-to-script-hash and pay-to-pubkey-hash, which are more constrained than the other types:
 657
 658             // It is always OP_HASH160 20 [20 byte hash] OP_EQUAL
 659             if (scriptPubKey.IsPayToScriptHash())
 660             {
 661                 typeRet = txnouttype.TX_SCRIPTHASH;
 662
 663                 // Take 20 bytes with offset of 2 bytes
 664                 IEnumerable<byte> hashBytes = scriptPubKey.Enumerable.Skip(2).Take(20);
 665                 solutions.Add(hashBytes);
 666
 667                 return true;
 668             }
 669
 670             // It is always OP_DUP OP_HASH160 20 [20 byte hash] OP_EQUALVERIFY OP_CHECKSIG
 671             if (scriptPubKey.IsPayToPubKeyHash())
 672             {
 673                 typeRet = txnouttype.TX_PUBKEYHASH;
 674
 675                 // Take 20 bytes with offset of 3 bytes
 676                 IEnumerable<byte> hashBytes = scriptPubKey.Enumerable.Skip(3).Take(20);
 677                 solutions.Add(hashBytes);
 678
 679                 return true;
 680             }
 681
 682             List<Tuple<txnouttype, IEnumerable<byte>>> templateTuples = new List<Tuple<txnouttype, IEnumerable<byte>>>();
 683
 684             // Sender provides pubkey, receiver adds signature
 685             // [ECDSA public key] OP_CHECKSIG
 686             templateTuples.Add(
 687                 new Tuple<txnouttype, IEnumerable<byte>>(
 688                     txnouttype.TX_PUBKEY,
 689                     new byte[] { (byte)opcodetype.OP_PUBKEY, (byte)opcodetype.OP_CHECKSIG })
 690             );
 691
 692             // Sender provides N pubkeys, receivers provides M signatures
 693             // N [pubkey1] [pubkey2] ... [pubkeyN] M OP_CHECKMULTISIG
 694             // Where N and M are small integer opcodes (OP1 ... OP_16)
 695             templateTuples.Add(
 696                 new Tuple<txnouttype, IEnumerable<byte>>(
 697                     txnouttype.TX_MULTISIG,
 698                     new byte[] { (byte)opcodetype.OP_SMALLINTEGER, (byte)opcodetype.OP_PUBKEYS, (byte)opcodetype.OP_SMALLINTEGER, (byte)opcodetype.OP_CHECKMULTISIG })
 699             );
 700
 701             // Data-carrying output
 702             // OP_RETURN [up to 80 bytes of data]
 703             templateTuples.Add(
 704                 new Tuple<txnouttype, IEnumerable<byte>>(
 705                     txnouttype.TX_NULL_DATA,
 706                     new byte[] { (byte)opcodetype.OP_RETURN, (byte)opcodetype.OP_SMALLDATA })
 707             );
 708
 709             // Nonstandard tx output
 710             typeRet = txnouttype.TX_NONSTANDARD;
 711
 712             foreach (Tuple<txnouttype, IEnumerable<byte>> templateTuple in templateTuples)
 713             {
 714                 CScript script2 = new CScript(templateTuple.Item2);
 715                 CScript script1 = scriptPubKey;
 716
 717                 opcodetype opcode1, opcode2;
 718
 719                 // Compare
 720                 WrappedList<byte> wl1 = script1.GetWrappedList();
 721                 WrappedList<byte> wl2 = script2.GetWrappedList();
 722
 723                 IEnumerable<byte> args1, args2;
 724
 725                 byte last1 = script1.Enumerable.Last();
 726                 byte last2 = script2.Enumerable.Last();
 727
 728                 while (true)
 729                 {
 730                     if (wl1.GetItem() == last1 && wl2.GetItem() == last2)
 731                     {
 732                         // Found a match
 733                         typeRet = templateTuple.Item1;
 734                         if (typeRet == txnouttype.TX_MULTISIG)
 735                         {
 736                             // Additional checks for TX_MULTISIG:
 737                             byte m = solutions.First().First();
 738                             byte n = solutions.Last().First();
 739
 740                             if (m < 1 || n < 1 || m > n || solutions.Count - 2 != n)
 741                             {
 742                                 return false;
 743                             }
 744                         }
 745                         return true;
 746                     }
 747
 748                     if (!GetOp(ref wl1, out opcode1, out args1))
 749                     {
 750                         break;
 751                     }
 752                     if (!GetOp(ref wl2, out opcode2, out args2))
 753                     {
 754                         break;
 755                     }
 756
 757                     // Template matching opcodes:
 758                     if (opcode2 == opcodetype.OP_PUBKEYS)
 759                     {
 760                         while (args1.Count() >= 33 && args1.Count() <= 120)
 761                         {
 762                             solutions.Add(args1);
 763                             if (!GetOp(ref wl1, out opcode1, out args1))
 764                             {
 765                                 break;
 766                             }
 767                         }
 768                         if (!GetOp(ref wl2, out opcode2, out args2))
 769                             break;
 770                         // Normal situation is to fall through
 771                         // to other if/else statements
 772                     }
 773                     if (opcode2 == opcodetype.OP_PUBKEY)
 774                     {
 775                         if (args1.Count() < 33 || args1.Count() > 120)
 776                         {
 777                             break;
 778                         }
 779                         solutions.Add(args1);
 780                     }
 781                     else if (opcode2 == opcodetype.OP_PUBKEYHASH)
 782                     {
 783                         if (args1.Count() != 20) // hash160 size
 784                         {
 785                             break;
 786                         }
 787                         solutions.Add(args1);
 788                     }
 789                     else if (opcode2 == opcodetype.OP_SMALLINTEGER)
 790                     {
 791                         // Single-byte small integer pushed onto solutions
 792                         if (opcode1 == opcodetype.OP_0 || (opcode1 >= opcodetype.OP_1 && opcode1 <= opcodetype.OP_16))
 793                         {
 794                             byte n = (byte)DecodeOP_N(opcode1);
 795                             solutions.Add(new byte[] { n });
 796                         }
 797                         else
 798                         {
 799                             break;
 800                         }
 801                     }
 802                     else if (opcode2 == opcodetype.OP_SMALLDATA)
 803                     {
 804                         // small pushdata, <= 80 bytes
 805                         if (args1.Count() > 80)
 806                         {
 807                             break;
 808                         }
 809                     }
 810                     else if (opcode1 != opcode2 || args1.SequenceEqual(args2))
 811                     {
 812                         // Others must match exactly
 813                         break;
 814                     }
 815                 }
 816             }
 817
 818             solutions.Clear();
 819             typeRet = txnouttype.TX_NONSTANDARD;
 820
 821             return false;
 822         }
 823     };
 824 }