/**
* Novacoin classes library
* Copyright (C) 2015 Alex D. (balthazar.ad@gmail.com)
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see .
*/
using System;
using System.Linq;
using System.Text;
using System.Collections.Generic;
using System.Diagnostics.Contracts;
namespace Novacoin
{
///
/// Representation of script code
///
public class CScript
{
private List codeBytes;
///
/// Initializes an empty instance of CScript
///
public CScript ()
{
codeBytes = new List();
}
///
/// Initializes new instance of CScript and fills it with supplied bytes
///
/// Enumerator interface for byte sequence
public CScript(byte[] bytes)
{
codeBytes = new List(bytes);
}
///
/// Return a new instance of ByteQueue object for current code bytes
///
///
public InstructionQueue GetInstructionQueue()
{
return new InstructionQueue(ref codeBytes);
}
///
/// Adds specified operation to instruction list
///
///
public void AddInstruction(instruction opcode)
{
Contract.Requires(opcode >= instruction.OP_0 && opcode <= instruction.OP_INVALIDOPCODE, "Invalid instruction.");
codeBytes.Add((byte)opcode);
}
///
/// Adds hash to instruction list.
/// New items are added in this format:
/// hash_length_byte hash_bytes
///
/// uint160 instance
public void AddHash(uint160 hash)
{
codeBytes.Add((byte)hash.Size);
codeBytes.AddRange((byte[])hash);
}
///
/// Adds hash to instruction list.
/// New items are added in this format:
/// hash_length_byte hash_bytes
///
/// uint256 instance
public void AddHash(uint256 hash)
{
codeBytes.Add((byte)hash.Size);
codeBytes.AddRange((byte[])hash);
}
///
/// Create new OP_PUSHDATAn operator and add it to instruction list
///
/// Set of data bytes
public void PushData(byte[] dataBytes)
{
var nCount = dataBytes.LongLength;
if (nCount < (int)instruction.OP_PUSHDATA1)
{
// OP_0 and OP_FALSE
codeBytes.Add((byte)nCount);
}
else if (nCount < 0xff)
{
// OP_PUSHDATA1 0x01 [0x5a]
codeBytes.Add((byte)instruction.OP_PUSHDATA1);
codeBytes.Add((byte)nCount);
}
else if (nCount < 0xffff)
{
// OP_PUSHDATA1 0x01 0x00 [0x5a]
codeBytes.Add((byte)instruction.OP_PUSHDATA2);
var szBytes = BitConverter.GetBytes((ushort)nCount);
codeBytes.AddRange(szBytes);
}
else if (nCount < 0xffffffff)
{
// OP_PUSHDATA1 0x01 0x00 0x00 0x00 [0x5a]
codeBytes.Add((byte)instruction.OP_PUSHDATA4);
var szBytes = BitConverter.GetBytes((uint)nCount);
codeBytes.AddRange(szBytes);
}
// Add data bytes
codeBytes.AddRange(dataBytes);
}
///
/// Just insert data array without including any prefixes. Please make sure that you know what you're doing,
/// it is recommended to use AddInstruction, AddHash or PushData instead.
///
/// Data bytes
public void AddRawData(byte[] dataBytes)
{
// Add data bytes
codeBytes.AddRange(dataBytes);
}
///
/// Scan pushed data bytes for pattern and, in case of exact match, remove it.
///
/// Pattern sequence
/// Matches count
public int RemovePattern(byte[] pattern)
{
// There is no sense to continue if pattern is empty or longer than script itself
if (pattern.Length == 0 || pattern.Length > codeBytes.Count)
{
return 0;
}
var count = 0;
var bq1 = new InstructionQueue(ref codeBytes);
byte[] pushData;
instruction opcode;
var newScript = new CScript();
while (ScriptCode.GetOp(ref bq1, out opcode, out pushData))
{
if (pushData.Length == 0)
{
// No data, put instruction on its place
newScript.AddInstruction(opcode);
}
else if (!pushData.SequenceEqual(pattern))
{
// No match, create push operator
newScript.PushData(pushData);
}
else
{
count++; // match
}
}
if (count > 0)
{
// Replace current script if any matches were found
codeBytes = newScript.codeBytes;
}
return count;
}
///
/// Scan script for specific instruction and remove it if there are some matches.
///
/// Instruction
/// Matches count
public int RemoveInstruction(instruction op)
{
byte[] pushData;
instruction opcode;
var count = 0;
var newScript = new CScript();
var bq1 = new InstructionQueue(ref codeBytes);
while (ScriptCode.GetOp(ref bq1, out opcode, out pushData))
{
if (pushData.Length != 0 && op != opcode)
{
// If instruction didn't match then push its data again
newScript.PushData(pushData);
}
else if (Enum.IsDefined(typeof(instruction), op) && op != opcode)
{
// Instruction didn't match
newScript.AddInstruction(opcode);
}
else
{
count++; // match
}
}
if (count > 0)
{
// Replace current script if any matches were found
codeBytes = newScript.codeBytes;
}
return count;
}
///
/// Is it true that script doesn't contain anything except push value operations?
///
public bool IsPushOnly
{
get
{
var wCodeBytes = new InstructionQueue(ref codeBytes);
instruction opcode; // Current instruction
byte[] pushArgs; // OP_PUSHDATAn argument
// Scan instructions sequence
while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
{
if (opcode > instruction.OP_16)
{
// We don't allow control instructions here
return false;
}
}
return true;
}
}
///
/// Is it true that script doesn't contain non-canonical push operations?
///
public bool HasOnlyCanonicalPushes
{
get
{
var wCodeBytes = new InstructionQueue(ref codeBytes);
byte[] pushArgs; // OP_PUSHDATAn argument
instruction opcode; // Current instruction
// Scan instructions sequence
while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
{
var data = pushArgs;
if (opcode < instruction.OP_PUSHDATA1 && opcode > instruction.OP_0 && (data.Length == 1 && data[0] <= 16))
{
// Could have used an OP_n code, rather than a 1-byte push.
return false;
}
if (opcode == instruction.OP_PUSHDATA1 && data.Length < (int)instruction.OP_PUSHDATA1)
{
// Could have used a normal n-byte push, rather than OP_PUSHDATA1.
return false;
}
if (opcode == instruction.OP_PUSHDATA2 && data.Length <= 0xFF)
{
// Could have used an OP_PUSHDATA1.
return false;
}
if (opcode == instruction.OP_PUSHDATA4 && data.LongLength <= 0xFFFF)
{
// Could have used an OP_PUSHDATA2.
return false;
}
}
return true;
}
}
///
/// Quick test for pay-to-script-hash CScripts
///
public bool IsPayToScriptHash
{
get
{
// Sender provides redeem script hash, receiver provides signature list and redeem script
// OP_HASH160 20 [20 byte hash] OP_EQUAL
return (codeBytes.Count() == 23 &&
codeBytes[0] == (byte)instruction.OP_HASH160 &&
codeBytes[1] == 0x14 && // 20 bytes hash length prefix
codeBytes[22] == (byte)instruction.OP_EQUAL);
}
}
///
/// Quick test for pay-to-pubkeyhash CScripts
///
public bool IsPayToPubKeyHash
{
get
{
// Sender provides hash of pubkey, receiver provides signature and pubkey
// OP_DUP OP_HASH160 20 [20 byte hash] OP_EQUALVERIFY OP_CHECKSIG
return (codeBytes.Count == 25 &&
codeBytes[0] == (byte)instruction.OP_DUP &&
codeBytes[1] == (byte)instruction.OP_HASH160 &&
codeBytes[2] == 0x14 && // 20 bytes hash length prefix
codeBytes[23] == (byte)instruction.OP_EQUALVERIFY &&
codeBytes[24] == (byte)instruction.OP_CHECKSIG);
}
}
///
/// Quick test for Null destination
///
public bool IsNull
{
get { return codeBytes.Count == 0; }
}
///
/// Pre-version-0.6, Bitcoin always counted CHECKMULTISIGs
/// as 20 sigops. With pay-to-script-hash, that changed:
/// CHECKMULTISIGs serialized in scriptSigs are
/// counted more accurately, assuming they are of the form
/// ... OP_N CHECKMULTISIG ...
///
/// Legacy mode flag
/// Amount of sigops
public uint GetSigOpCount(bool fAccurate)
{
var wCodeBytes = new InstructionQueue(ref codeBytes);
instruction opcode; // Current instruction
byte[] pushArgs; // OP_PUSHDATAn argument
uint nCount = 0;
var lastOpcode = instruction.OP_INVALIDOPCODE;
// Scan instructions sequence
while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
{
if (opcode == instruction.OP_CHECKSIG || opcode == instruction.OP_CHECKSIGVERIFY)
{
nCount++;
}
else if (opcode == instruction.OP_CHECKMULTISIG || opcode == instruction.OP_CHECKMULTISIGVERIFY)
{
if (fAccurate && lastOpcode >= instruction.OP_1 && lastOpcode <= instruction.OP_16)
{
nCount += (uint)ScriptCode.DecodeOP_N(lastOpcode);
}
else
{
nCount += 20;
}
}
}
return nCount;
}
///
/// Accurately count sigOps, including sigOps in
/// pay-to-script-hash transactions
///
/// pay-to-script-hash scriptPubKey
/// SigOps count
public uint GetSigOpCount(CScript scriptSig)
{
if (!IsPayToScriptHash)
{
return GetSigOpCount(true);
}
// This is a pay-to-script-hash scriptPubKey;
// get the last item that the scriptSig
// pushes onto the stack:
InstructionQueue wScriptSig = scriptSig.GetInstructionQueue();
uint nScriptSigSize = scriptSig.Size;
instruction opcode; // Current instruction
byte[] pushArgs = new byte[0]; // OP_PUSHDATAn argument
while (wScriptSig.Index < nScriptSigSize)
{
if (!ScriptCode.GetOp(ref wScriptSig, out opcode, out pushArgs))
{
return 0;
}
if (opcode > instruction.OP_16)
{
return 0;
}
}
/// ... and return its opcount:
var subScript = new CScript(pushArgs);
return subScript.GetSigOpCount(true);
}
///
/// Set pay-to-pubkey destination.
///
/// Instance of CPubKey.
public void SetDestination(CPubKey pubKey)
{
codeBytes.Clear();
PushData(pubKey);
AddInstruction(instruction.OP_CHECKSIG);
}
///
/// Set pay-to-pubkeyhash destination
///
/// Public key hash
public void SetDestination(CKeyID ID)
{
codeBytes.Clear();
AddInstruction(instruction.OP_DUP);
AddInstruction(instruction.OP_HASH160);
AddHash(ID);
AddInstruction(instruction.OP_EQUALVERIFY);
AddInstruction(instruction.OP_CHECKSIG);
}
///
/// Set pay-to-scripthash destination
///
/// Script hash
public void SetDestination(CScriptID ID)
{
codeBytes.Clear();
AddInstruction(instruction.OP_HASH160);
AddHash(ID);
AddInstruction(instruction.OP_EQUAL);
}
///
/// Reset script code buffer.
///
public void SetNullDestination()
{
codeBytes.Clear();
}
///
/// Set multisig destination.
///
/// Amount of required signatures.
/// Set of public keys.
public void SetMultiSig(int nRequired, CPubKey[] keys)
{
codeBytes.Clear();
AddInstruction(ScriptCode.EncodeOP_N(nRequired));
foreach (var key in keys)
{
PushData(key);
}
AddInstruction(ScriptCode.EncodeOP_N(keys.Length));
AddInstruction(instruction.OP_CHECKMULTISIG);
}
///
/// Access to script code.
///
public static implicit operator byte[] (CScript script)
{
return script.codeBytes.ToArray();
}
///
/// Implicit cast of byte array to CScript.
///
///
public static implicit operator CScript(byte[] scriptBytes)
{
return new CScript(scriptBytes);
}
///
/// Script size
///
public uint Size
{
get { return (uint) codeBytes.Count; }
}
public CScriptID ScriptID
{
get { return new CScriptID(CryptoUtils.ComputeHash160(codeBytes.ToArray())); }
}
///
/// Disassemble current script code
///
/// Code listing
public override string ToString()
{
var sb = new StringBuilder();
var wCodeBytes = new InstructionQueue(ref codeBytes);
instruction opcode; // Current instruction
byte[] pushArgs; // OP_PUSHDATAn argument
while (ScriptCode.GetOp(ref wCodeBytes, out opcode, out pushArgs))
{
if (sb.Length != 0)
{
sb.Append(" ");
}
if (0 <= opcode && opcode <= instruction.OP_PUSHDATA4)
{
sb.Append(ScriptCode.ValueString(pushArgs));
}
else
{
sb.Append(ScriptCode.GetOpName(opcode));
}
}
return sb.ToString();
}
}
}