public override bool Equals(object obj)
{
if (this == obj)
{
return(true);
}
if (obj == null)
{
return(false);
}
ScriptChunk other = (ScriptChunk)obj;
return(this.Opcode == other.Opcode && this.startLocationInProgram == other.startLocationInProgram && this.Data.Equals(other.Data));
}
/// <summary>
/// Returns the public key in this script. If a script contains two constants and nothing else, it is assumed to
/// be a scriptSig (input) for a pay-to-address output and the second constant is returned (the first is the
/// signature). If a script contains a constant and an ScriptOpCodes.OP_CHECKSIG opcode, the constant is returned as it is
/// assumed to be a direct pay-to-key scriptPubKey (output) and the first constant is the public key.
/// </summary>
public byte[] GetPubKey()
{
Thrower.If(this.Chunks.Count() != 2).Throw <ScriptException>("Script not of right size, expecting 2 but got " + this.Chunks.Count());
ScriptChunk firstChunk = this.Chunks.ElementAt(0);
ScriptChunk secondChunk = this.Chunks.ElementAt(1);
if (firstChunk.Data != null && firstChunk.Data.Length > 2 && secondChunk.Data != null && secondChunk.Data.Length > 2)
{
// If we have two large constants assume the input to a pay-to-address output.
return(secondChunk.Data);
}
if (secondChunk.EqualsOpCode(ScriptOpCodes.OP_CHECKSIG) && firstChunk.Data != null && firstChunk.Data.Length > 2)
{
// A large constant followed by an ScriptOpCodes.OP_CHECKSIG is the key.
return(firstChunk.Data);
}
throw new ScriptException("Script did not match expected form: " + this);
}
/// <summary>
/// Adds the given chunk at the given index in the program
/// </summary>
public ScriptBuilder AddChunk(int index, ScriptChunk chunk)
{
this.chunks.Insert(index, chunk);
return(this);
}
/// <summary>
/// Adds the given chunk to the end of the program
/// </summary>
public ScriptBuilder AddChunk(ScriptChunk chunk)
{
return(this.AddChunk(this.chunks.Count(), chunk));
}
/// <summary>
/// <p>To run a script, first we parse it which breaks it up into chunks representing pushes of data or logical
/// opcodes. Then we can run the parsed chunks.</p>
///
/// <p>The reason for this split, instead of just interpreting directly, is to make it easier
/// to reach into a programs structure and pull out bits of data without having to run it.
/// This is necessary to render the to/from addresses of transactions in a user interface.
/// Bitcoin Core does something similar.</p>
/// </summary>
/// <param name="program">
/// The program.
/// </param>
/// <exception cref="ScriptException">
/// </exception>
private void Parse(byte[] program)
{
this.Chunks = new List <ScriptChunk>(5); // Common size.
using (var stream = new MemoryStream(program))
{
using (var reader = new BinaryReader(stream))
{
var initialSize = reader.BaseStream.Length;
while (reader.Available() > 0)
{
var startLocationInProgram = reader.BaseStream.Position;
int opcode = reader.ReadByte();
long dataToRead = -1;
if (opcode >= 0 && opcode < ScriptOpCodes.OP_PUSHDATA1)
{
// Read some bytes of data, where how many is the opcode value itself.
dataToRead = opcode;
}
else if (opcode == ScriptOpCodes.OP_PUSHDATA1)
{
if (reader.Available() < 1)
{
throw new ScriptException("Unexpected end of script");
}
dataToRead = reader.ReadInt16();
}
else if (opcode == ScriptOpCodes.OP_PUSHDATA2)
{
// Read a short, then read that many bytes of data.
if (reader.Available() < 2)
{
throw new ScriptException("Unexpected end of script");
}
dataToRead = reader.ReadInt32();
}
else if (opcode == ScriptOpCodes.OP_PUSHDATA4)
{
// Read a uint32, then read that many bytes of data.
// Though this is allowed, because its value cannot be > 520, it should never actually be used
if (reader.Available() < 4)
{
throw new ScriptException("Unexpected end of script");
}
dataToRead = reader.ReadInt64();
}
ScriptChunk chunk;
if (dataToRead == -1)
{
chunk = new ScriptChunk(opcode, null, startLocationInProgram);
}
else
{
if (dataToRead > reader.Available())
{
throw new ScriptException("Push of data element that is larger than remaining data");
}
byte[] data = reader.ReadBytes((int)dataToRead);
chunk = new ScriptChunk(opcode, data, startLocationInProgram);
}
this.Chunks.Add(chunk);
}
}
}
}
