// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_COMPRESSOR_H
#define BITCOIN_COMPRESSOR_H
#include "primitives/transaction.h"
#include "script/script.h"
#include "serialize.h"
class CKeyID;
class CPubKey;
class CScriptID;
/** Compact serializer for scripts.
*
* It detects common cases and encodes them much more efficiently.
* 3 special cases are defined:
* * Pay to pubkey hash (encoded as 21 bytes)
* * Pay to script hash (encoded as 21 bytes)
* * Pay to pubkey starting with 0x02, 0x03 or 0x04 (encoded as 33 bytes)
*
* Other scripts up to 121 bytes require 1 byte + script length. Above
* that, scripts up to 16505 bytes require 2 bytes + script length.
*/
class CScriptCompressor
{
private:
/**
* make this static for now (there are only 6 special scripts defined)
* this can potentially be extended together with a new nVersion for
* transactions, in which case this value becomes dependent on nVersion
* and nHeight of the enclosing transaction.
*/
static const unsigned int nSpecialScripts = 6;
CScript &script;
protected:
/**
* These check for scripts for which a special case with a shorter encoding is defined.
* They are implemented separately from the CScript test, as these test for exact byte
* sequence correspondences, and are more strict. For example, IsToPubKey also verifies
* whether the public key is valid (as invalid ones cannot be represented in compressed
* form).
*/
bool IsToKeyID(CKeyID &hash) const;
bool IsToScriptID(CScriptID &hash) const;
bool IsToPubKey(CPubKey &pubkey) const;
bool Compress(std::vector