Novacoin/CScript.cs

   1 \feffusing System;
   2 using System.Linq;
   3 using System.Text;
   4
   5 using System.Collections;
   6 using System.Collections.Generic;
   7
   8 namespace Novacoin
   9 {
  10     public class CScriptException : Exception
  11     {
  12         public CScriptException()
  13         {
  14         }
  15
  16         public CScriptException(string message)
  17             : base(message)
  18         {
  19         }
  20
  21         public CScriptException(string message, Exception inner)
  22             : base(message, inner)
  23         {
  24         }
  25     }
  26
  27     /// <summary>
  28     /// Representation of script code
  29     /// </summary>
  30         public class CScript
  31         {
  32         private List<byte> codeBytes;
  33
  34         /// <summary>
  35         /// Initializes an empty instance of CScript
  36         /// </summary>
  37                 public CScript ()
  38                 {
  39             codeBytes = new List<byte>();
  40                 }
  41
  42         /// <summary>
  43         /// Initializes new instance of CScript and fills it with supplied bytes
  44         /// </summary>
  45         /// <param name="bytes">List of bytes</param>
  46         public CScript(IList<byte> bytes)
  47         {
  48             codeBytes = new List<byte>(bytes);
  49         }
  50
  51         /// <summary>
  52         /// Initializes new instance of CScript and fills it with supplied bytes
  53         /// </summary>
  54         /// <param name="bytes">Array of bytes</param>
  55         public CScript(byte[] bytes)
  56         {
  57             codeBytes = new List<byte>(bytes);
  58         }
  59
  60         /// <summary>
  61         /// Adds specified operation to opcode bytes list
  62         /// </summary>
  63         /// <param name="opcode"></param>
  64         public void AddOp(opcodetype opcode)
  65         {
  66             if (opcode < opcodetype.OP_0 || opcode > opcodetype.OP_INVALIDOPCODE)
  67             {
  68                 throw new CScriptException("CScript::AddOp() : invalid opcode");
  69             }
  70
  71             codeBytes.Add((byte)opcode);
  72         }
  73
  74         /// <summary>
  75         /// Adds hash to opcode bytes list.
  76         ///    New items are added in this format:
  77         ///    hash_length_byte hash_bytes
  78         /// </summary>
  79         /// <param name="hash">Hash160 instance</param>
  80         public void AddHash(Hash160 hash)
  81         {
  82             codeBytes.Add((byte)hash.hashSize);
  83             codeBytes.AddRange(hash.hashBytes);
  84         }
  85
  86         /// <summary>
  87         /// Adds hash to opcode bytes list.
  88         ///    New items are added in this format:
  89         ///    hash_length_byte hash_bytes
  90         /// </summary>
  91         /// <param name="hash">Hash256 instance</param>
  92         public void AddHash(Hash256 hash)
  93         {
  94             codeBytes.Add((byte)hash.hashSize);
  95             codeBytes.AddRange(hash.hashBytes);
  96         }
  97
  98         /// <summary>
  99         /// Create new OP_PUSHDATAn operator and add it to opcode bytes list
 100         /// </summary>
 101         /// <param name="dataBytes">List of data bytes</param>
 102         public void PushData(IList<byte> dataBytes)
 103         {
 104             if (dataBytes.Count < (int)opcodetype.OP_PUSHDATA1)
 105             {
 106                 // OP_0 and OP_FALSE
 107                 codeBytes.Add((byte)dataBytes.Count);
 108             }
 109             else if (dataBytes.Count < 0xff)
 110             {
 111                 // OP_PUSHDATA1 0x01 [0x5a]
 112                 codeBytes.Add((byte)opcodetype.OP_PUSHDATA1);
 113                 codeBytes.Add((byte)dataBytes.Count);
 114             }
 115             else if (dataBytes.Count < 0xffff)
 116             {
 117                 // OP_PUSHDATA1 0x00 0x01 [0x5a]
 118                 codeBytes.Add((byte)opcodetype.OP_PUSHDATA2);
 119
 120                 byte[] szBytes = BitConverter.GetBytes((short)dataBytes.Count);
 121                 if (BitConverter.IsLittleEndian)
 122                 {
 123                     Array.Reverse(szBytes);
 124                 }
 125                 codeBytes.AddRange(szBytes);
 126             }
 127             else if ((uint)dataBytes.Count < 0xffffffff)
 128             {
 129                 // OP_PUSHDATA1 0x00 0x00 0x00 0x01 [0x5a]
 130                 codeBytes.Add((byte)opcodetype.OP_PUSHDATA4);
 131
 132                 byte[] szBytes = BitConverter.GetBytes((uint)dataBytes.Count);
 133                 if (BitConverter.IsLittleEndian)
 134                 {
 135                     Array.Reverse(szBytes);
 136                 }
 137                 codeBytes.AddRange(szBytes);
 138             }
 139
 140             // Add data bytes
 141             codeBytes.AddRange(dataBytes);
 142         }
 143
 144         /// <summary>
 145         /// Scan code bytes for pattern
 146         /// </summary>
 147         /// <param name="pattern">Pattern sequence</param>
 148         /// <returns>Matches enumerator</returns>
 149         private IEnumerable<int> FindPattern(IList<byte> pattern)
 150         {
 151             for (int i = 0; i < codeBytes.Count; i++)
 152             {
 153                 if (codeBytes.Skip(i).Take(pattern.Count).SequenceEqual(pattern))
 154                 {
 155                     yield return i;
 156                 }
 157             }
 158         }
 159
 160         /// <summary>
 161         /// Scan code bytes for pattern and remove it
 162         /// </summary>
 163         /// <param name="pattern">Pattern sequence</param>
 164         /// <returns>Matches number</returns>
 165         public int RemovePattern(IList<byte> pattern)
 166         {
 167             List<byte> resultBytes = new List<byte>(codeBytes);
 168             int count = 0;
 169             int patternLen = pattern.Count;
 170
 171             foreach (int i in FindPattern(pattern))
 172             {
 173                 resultBytes.RemoveRange(i - count * patternLen, patternLen);
 174                 count++;
 175             }
 176
 177             codeBytes = resultBytes;
 178
 179             return count;
 180         }
 181
 182         /// <summary>
 183         /// Is it true that script doesn't contain anything except push value operations?
 184         /// </summary>
 185         /// <returns>Checking result</returns>
 186         public bool IsPushonly()
 187         {
 188             WrappedList<byte> wCodeBytes = new WrappedList<byte>(codeBytes);
 189
 190             opcodetype opcode; // Current opcode
 191             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 192
 193             // Scan opcodes sequence
 194             while (ScriptOpcode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 195             {
 196                 if (opcode > opcodetype.OP_16)
 197                 {
 198                     // We don't allow control opcodes here
 199                     return false;
 200                 }
 201             }
 202
 203             return true;
 204         }
 205
 206         /// <summary>
 207         /// Is it true that script doesn't contain non-canonical push operations?
 208         /// </summary>
 209         /// <returns>Checking result</returns>
 210         public bool HashOnlyCanonicalPushes()
 211         {
 212             WrappedList<byte> wCodeBytes = new WrappedList<byte>(codeBytes);
 213
 214             opcodetype opcode; // Current opcode
 215             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 216
 217             // Scan opcodes sequence
 218             while (ScriptOpcode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 219             {
 220                 byte[] data = pushArgs.ToArray();
 221
 222                 if (opcode < opcodetype.OP_PUSHDATA1 && opcode > opcodetype.OP_0 && (data.Length == 1 && data[0] <= 16))
 223                     // Could have used an OP_n code, rather than a 1-byte push.
 224                     return false;
 225                 if (opcode == opcodetype.OP_PUSHDATA1 && data.Length < (int)opcodetype.OP_PUSHDATA1)
 226                     // Could have used a normal n-byte push, rather than OP_PUSHDATA1.
 227                     return false;
 228                 if (opcode == opcodetype.OP_PUSHDATA2 && data.Length <= 0xFF)
 229                     // Could have used an OP_PUSHDATA1.
 230                     return false;
 231                 if (opcode == opcodetype.OP_PUSHDATA4 && data.Length <= 0xFFFF)
 232                     // Could have used an OP_PUSHDATA2.
 233                     return false;
 234             }
 235
 236             return true;
 237         }
 238
 239
 240         /// <summary>
 241         /// Disassemble current script code
 242         /// </summary>
 243         /// <returns>Code listing</returns>
 244                 public override string ToString()
 245                 {
 246                         StringBuilder sb = new StringBuilder();
 247             WrappedList<byte> wCodeBytes = new WrappedList<byte>(codeBytes);
 248
 249             opcodetype opcode; // Current opcode
 250             IEnumerable<byte> pushArgs; // OP_PUSHDATAn argument
 251             while (ScriptOpcode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
 252             {
 253                 if (sb.Length != 0)
 254                 {
 255                     sb.Append(" ");
 256                 }
 257
 258                 if (0 <= opcode && opcode <= opcodetype.OP_PUSHDATA4)
 259                 {
 260                     sb.Append(ScriptOpcode.ValueString(pushArgs));
 261                 }
 262                 else
 263                 {
 264                     sb.Append(ScriptOpcode.GetOpName(opcode));
 265                 }
 266             }
 267
 268             return sb.ToString();
 269                 }
 270         }
 271 }
 272