Compact serialization for scripts
Special serializers for script which detect common cases and encode 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.
This commit is contained in:
parent
4d6144f97f
commit
69fc8047a9
5 changed files with 213 additions and 4 deletions
|
@ -120,9 +120,9 @@ err:
|
|||
return ret;
|
||||
}
|
||||
|
||||
void CKey::SetCompressedPubKey()
|
||||
void CKey::SetCompressedPubKey(bool fCompressed)
|
||||
{
|
||||
EC_KEY_set_conv_form(pkey, POINT_CONVERSION_COMPRESSED);
|
||||
EC_KEY_set_conv_form(pkey, fCompressed ? POINT_CONVERSION_COMPRESSED : POINT_CONVERSION_UNCOMPRESSED);
|
||||
fCompressedPubKey = true;
|
||||
}
|
||||
|
||||
|
|
|
@ -113,9 +113,8 @@ protected:
|
|||
bool fSet;
|
||||
bool fCompressedPubKey;
|
||||
|
||||
void SetCompressedPubKey();
|
||||
|
||||
public:
|
||||
void SetCompressedPubKey(bool fCompressed = true);
|
||||
|
||||
void Reset();
|
||||
|
||||
|
|
14
src/main.h
14
src/main.h
|
@ -647,6 +647,20 @@ protected:
|
|||
const CTxOut& GetOutputFor(const CTxIn& input, const MapPrevTx& inputs) const;
|
||||
};
|
||||
|
||||
/** wrapper for CTxOut that provides a more compact serialization */
|
||||
class CTxOutCompressor
|
||||
{
|
||||
private:
|
||||
CTxOut &txout;
|
||||
public:
|
||||
CTxOutCompressor(CTxOut &txoutIn) : txout(txoutIn) { }
|
||||
|
||||
IMPLEMENT_SERIALIZE(
|
||||
READWRITE(VARINT(txout.nValue));
|
||||
CScriptCompressor cscript(REF(txout.scriptPubKey));
|
||||
READWRITE(cscript);
|
||||
)
|
||||
};
|
||||
|
||||
|
||||
|
||||
|
|
125
src/script.cpp
125
src/script.cpp
|
@ -1951,3 +1951,128 @@ void CScript::SetMultisig(int nRequired, const std::vector<CKey>& keys)
|
|||
*this << key.GetPubKey();
|
||||
*this << EncodeOP_N(keys.size()) << OP_CHECKMULTISIG;
|
||||
}
|
||||
|
||||
bool CScriptCompressor::IsToKeyID(CKeyID &hash) const
|
||||
{
|
||||
if (script.size() == 25 && script[0] == OP_DUP && script[1] == OP_HASH160
|
||||
&& script[2] == 20 && script[23] == OP_EQUALVERIFY
|
||||
&& script[24] == OP_CHECKSIG) {
|
||||
memcpy(&hash, &script[3], 20);
|
||||
return true;
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
bool CScriptCompressor::IsToScriptID(CScriptID &hash) const
|
||||
{
|
||||
if (script.size() == 23 && script[0] == OP_HASH160 && script[1] == 20
|
||||
&& script[22] == OP_EQUAL) {
|
||||
memcpy(&hash, &script[2], 20);
|
||||
return true;
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
bool CScriptCompressor::IsToPubKey(std::vector<unsigned char> &pubkey) const
|
||||
{
|
||||
if (script.size() == 35 && script[0] == 33 && script[34] == OP_CHECKSIG
|
||||
&& (script[1] == 0x02 || script[1] == 0x03)) {
|
||||
pubkey.resize(33);
|
||||
memcpy(&pubkey[0], &script[1], 33);
|
||||
return true;
|
||||
}
|
||||
if (script.size() == 67 && script[0] == 65 && script[66] == OP_CHECKSIG
|
||||
&& script[1] == 0x04) {
|
||||
pubkey.resize(65);
|
||||
memcpy(&pubkey[0], &script[1], 65);
|
||||
CKey key;
|
||||
return (key.SetPubKey(CPubKey(pubkey))); // SetPubKey fails if this is not a valid public key, a case that would not be compressible
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
bool CScriptCompressor::Compress(std::vector<unsigned char> &out) const
|
||||
{
|
||||
CKeyID keyID;
|
||||
if (IsToKeyID(keyID)) {
|
||||
out.resize(21);
|
||||
out[0] = 0x00;
|
||||
memcpy(&out[1], &keyID, 20);
|
||||
return true;
|
||||
}
|
||||
CScriptID scriptID;
|
||||
if (IsToScriptID(scriptID)) {
|
||||
out.resize(21);
|
||||
out[0] = 0x01;
|
||||
memcpy(&out[1], &scriptID, 20);
|
||||
return true;
|
||||
}
|
||||
std::vector<unsigned char> pubkey;
|
||||
if (IsToPubKey(pubkey)) {
|
||||
out.resize(33);
|
||||
memcpy(&out[1], &pubkey[1], 32);
|
||||
if (pubkey[0] == 0x02 || pubkey[0] == 0x03) {
|
||||
out[0] = pubkey[0];
|
||||
return true;
|
||||
} else if (pubkey[0] == 0x04) {
|
||||
out[0] = 0x04 | (pubkey[64] & 0x01);
|
||||
return true;
|
||||
}
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
unsigned int CScriptCompressor::GetSpecialSize(unsigned int nSize) const
|
||||
{
|
||||
if (nSize == 0 || nSize == 1)
|
||||
return 20;
|
||||
if (nSize == 2 || nSize == 3 || nSize == 4 || nSize == 5)
|
||||
return 32;
|
||||
return 0;
|
||||
}
|
||||
|
||||
bool CScriptCompressor::Decompress(unsigned int nSize, const std::vector<unsigned char> &in)
|
||||
{
|
||||
switch(nSize) {
|
||||
case 0x00:
|
||||
script.resize(25);
|
||||
script[0] = OP_DUP;
|
||||
script[1] = OP_HASH160;
|
||||
script[2] = 20;
|
||||
memcpy(&script[3], &in[0], 20);
|
||||
script[23] = OP_EQUALVERIFY;
|
||||
script[24] = OP_CHECKSIG;
|
||||
return true;
|
||||
case 0x01:
|
||||
script.resize(23);
|
||||
script[0] = OP_HASH160;
|
||||
script[1] = 20;
|
||||
memcpy(&script[2], &in[0], 20);
|
||||
script[22] = OP_EQUAL;
|
||||
return true;
|
||||
case 0x02:
|
||||
case 0x03:
|
||||
script.resize(35);
|
||||
script[0] = 33;
|
||||
script[1] = nSize;
|
||||
memcpy(&script[2], &in[0], 32);
|
||||
script[34] = OP_CHECKSIG;
|
||||
return true;
|
||||
case 0x04:
|
||||
case 0x05:
|
||||
std::vector<unsigned char> vch(33, 0x00);
|
||||
vch[0] = nSize - 2;
|
||||
memcpy(&vch[1], &in[0], 32);
|
||||
CKey key;
|
||||
if (!key.SetPubKey(CPubKey(vch)))
|
||||
return false;
|
||||
key.SetCompressedPubKey(false); // Decompress public key
|
||||
CPubKey pubkey = key.GetPubKey();
|
||||
script.resize(67);
|
||||
script[0] = 65;
|
||||
memcpy(&script[1], &pubkey.Raw()[0], 65);
|
||||
script[66] = OP_CHECKSIG;
|
||||
return true;
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
|
71
src/script.h
71
src/script.h
|
@ -579,7 +579,78 @@ public:
|
|||
}
|
||||
};
|
||||
|
||||
/** 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(std::vector<unsigned char> &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[0], &compr[compr.size()]);
|
||||
return;
|
||||
}
|
||||
unsigned int nSize = script.size() + nSpecialScripts;
|
||||
s << VARINT(nSize);
|
||||
s << CFlatData(&script[0], &script[script.size()]);
|
||||
}
|
||||
|
||||
template<typename Stream>
|
||||
void Unserialize(Stream &s, int nType, int nVersion) {
|
||||
unsigned int nSize;
|
||||
s >> VARINT(nSize);
|
||||
if (nSize < nSpecialScripts) {
|
||||
std::vector<unsigned char> vch(GetSpecialSize(nSize), 0x00);
|
||||
s >> REF(CFlatData(&vch[0], &vch[vch.size()]));
|
||||
Decompress(nSize, vch);
|
||||
return;
|
||||
}
|
||||
nSize -= nSpecialScripts;
|
||||
script.resize(nSize);
|
||||
s >> REF(CFlatData(&script[0], &script[script.size()]));
|
||||
}
|
||||
};
|
||||
|
||||
bool IsCanonicalPubKey(const std::vector<unsigned char> &vchPubKey);
|
||||
bool IsCanonicalSignature(const std::vector<unsigned char> &vchSig);
|
||||
|
|
Loading…
Reference in a new issue