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author | Pieter Wuille <pieter.wuille@gmail.com> | 2014-10-28 05:22:34 -0700 |
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committer | Pieter Wuille <pieter.wuille@gmail.com> | 2014-10-28 05:27:41 -0700 |
commit | 723c7526368badda15df8ac1ffc047a0ab2e384a (patch) | |
tree | ee490e57014cea5b59355a48251b5df69020a90c /src/compressor.h | |
parent | cd9114e5136ecc1f60baa43fffeeb632782f2353 (diff) | |
parent | 99f41b9cf7b8e039cea75500a905498a1f6969f3 (diff) | |
download | bitcoin-723c7526368badda15df8ac1ffc047a0ab2e384a.tar.xz |
Merge pull request #5100
99f41b9 MOVEONLY: core.o -> core/block.o (jtimon)
561e9e9 MOVEONLY: Move script/compressor out of script and put CTxOutCompressor (from core) with it (jtimon)
999a2ab MOVEONLY: separate CTxUndo out of core (jtimon)
4a3587d MOVEONLY: Separate CTransaction and dependencies from core (jtimon)
eda3733 MOVEONLY: Move CFeeRate and Amount constants to amount.o (jtimon)
Diffstat (limited to 'src/compressor.h')
-rw-r--r-- | src/compressor.h | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/src/compressor.h b/src/compressor.h new file mode 100644 index 0000000000..a612c3a883 --- /dev/null +++ b/src/compressor.h @@ -0,0 +1,119 @@ +// Copyright (c) 2009-2010 Satoshi Nakamoto +// Copyright (c) 2009-2014 The Bitcoin developers +// Distributed under the MIT software license, see the accompanying +// file COPYING or http://www.opensource.org/licenses/mit-license.php. + +#ifndef H_BITCOIN_COMPRESSOR +#define H_BITCOIN_COMPRESSOR + +#include "core/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<unsigned char> &out) const; + unsigned int GetSpecialSize(unsigned int nSize) const; + bool Decompress(unsigned int nSize, const std::vector<unsigned char> &out); +public: + CScriptCompressor(CScript &scriptIn) : script(scriptIn) { } + + unsigned int GetSerializeSize(int nType, int nVersion) const { + std::vector<unsigned char> compr; + if (Compress(compr)) + return compr.size(); + unsigned int nSize = script.size() + nSpecialScripts; + return script.size() + VARINT(nSize).GetSerializeSize(nType, nVersion); + } + + template<typename Stream> + void Serialize(Stream &s, int nType, int nVersion) const { + std::vector<unsigned char> compr; + if (Compress(compr)) { + s << CFlatData(compr); + return; + } + unsigned int nSize = script.size() + nSpecialScripts; + s << VARINT(nSize); + s << CFlatData(script); + } + + template<typename Stream> + void Unserialize(Stream &s, int nType, int nVersion) { + unsigned int nSize = 0; + s >> VARINT(nSize); + if (nSize < nSpecialScripts) { + std::vector<unsigned char> vch(GetSpecialSize(nSize), 0x00); + s >> REF(CFlatData(vch)); + Decompress(nSize, vch); + return; + } + nSize -= nSpecialScripts; + script.resize(nSize); + s >> REF(CFlatData(script)); + } +}; + +/** wrapper for CTxOut that provides a more compact serialization */ +class CTxOutCompressor +{ +private: + CTxOut &txout; + +public: + static uint64_t CompressAmount(uint64_t nAmount); + static uint64_t DecompressAmount(uint64_t nAmount); + + CTxOutCompressor(CTxOut &txoutIn) : txout(txoutIn) { } + + ADD_SERIALIZE_METHODS; + + template <typename Stream, typename Operation> + inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) { + if (!ser_action.ForRead()) { + uint64_t nVal = CompressAmount(txout.nValue); + READWRITE(VARINT(nVal)); + } else { + uint64_t nVal = 0; + READWRITE(VARINT(nVal)); + txout.nValue = DecompressAmount(nVal); + } + CScriptCompressor cscript(REF(txout.scriptPubKey)); + READWRITE(cscript); + } +}; + +#endif // H_BITCOIN_COMPRESSOR |