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Move compressor utility functions out of class

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This commit is contained in:
Pieter Wuille 2017-07-08 16:43:34 -07:00
parent 2405ce1df0
commit 76a9aacd3f
3 changed files with 33 additions and 36 deletions
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30
src/compressor.cpp
View File

@ -9,7 +9,15 @@
#include <pubkey.h>
#include <script/standard.h>
bool CScriptCompressor::IsToKeyID(CKeyID &hash) const
/*
* 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).
*/
static bool IsToKeyID(const CScript& script, CKeyID &hash)
{
if (script.size() == 25 && script[0] == OP_DUP && script[1] == OP_HASH160
&& script[2] == 20 && script[23] == OP_EQUALVERIFY
@ -20,7 +28,7 @@ bool CScriptCompressor::IsToKeyID(CKeyID &hash) const
return false;
}
bool CScriptCompressor::IsToScriptID(CScriptID &hash) const
static bool IsToScriptID(const CScript& script, CScriptID &hash)
{
if (script.size() == 23 && script[0] == OP_HASH160 && script[1] == 20
&& script[22] == OP_EQUAL) {
@ -30,7 +38,7 @@ bool CScriptCompressor::IsToScriptID(CScriptID &hash) const
return false;
}
bool CScriptCompressor::IsToPubKey(CPubKey &pubkey) const
static bool IsToPubKey(const CScript& script, CPubKey &pubkey)
{
if (script.size() == 35 && script[0] == 33 && script[34] == OP_CHECKSIG
&& (script[1] == 0x02 || script[1] == 0x03)) {
@ -45,24 +53,24 @@ bool CScriptCompressor::IsToPubKey(CPubKey &pubkey) const
return false;
}
bool CScriptCompressor::Compress(std::vector<unsigned char> &out) const
bool CompressScript(const CScript& script, std::vector<unsigned char> &out)
{
CKeyID keyID;
if (IsToKeyID(keyID)) {
if (IsToKeyID(script, keyID)) {
out.resize(21);
out[0] = 0x00;
memcpy(&out[1], &keyID, 20);
return true;
}
CScriptID scriptID;
if (IsToScriptID(scriptID)) {
if (IsToScriptID(script, scriptID)) {
out.resize(21);
out[0] = 0x01;
memcpy(&out[1], &scriptID, 20);
return true;
}
CPubKey pubkey;
if (IsToPubKey(pubkey)) {
if (IsToPubKey(script, pubkey)) {
out.resize(33);
memcpy(&out[1], &pubkey[1], 32);
if (pubkey[0] == 0x02 || pubkey[0] == 0x03) {
@ -76,7 +84,7 @@ bool CScriptCompressor::Compress(std::vector<unsigned char> &out) const
return false;
}
unsigned int CScriptCompressor::GetSpecialSize(unsigned int nSize) const
unsigned int GetSpecialScriptSize(unsigned int nSize)
{
if (nSize == 0 || nSize == 1)
return 20;
@ -85,7 +93,7 @@ unsigned int CScriptCompressor::GetSpecialSize(unsigned int nSize) const
return 0;
}
bool CScriptCompressor::Decompress(unsigned int nSize, const std::vector<unsigned char> &in)
bool DecompressScript(CScript& script, unsigned int nSize, const std::vector<unsigned char> &in)
{
switch(nSize) {
case 0x00:
@ -139,7 +147,7 @@ bool CScriptCompressor::Decompress(unsigned int nSize, const std::vector<unsigne
// * if e==9, we only know the resulting number is not zero, so output 1 + 10*(n - 1) + 9
// (this is decodable, as d is in [1-9] and e is in [0-9])
uint64_t CTxOutCompressor::CompressAmount(uint64_t n)
uint64_t CompressAmount(uint64_t n)
{
if (n == 0)
return 0;
@ -158,7 +166,7 @@ uint64_t CTxOutCompressor::CompressAmount(uint64_t n)
}
}
uint64_t CTxOutCompressor::DecompressAmount(uint64_t x)
uint64_t DecompressAmount(uint64_t x)
{
// x = 0 OR x = 1+10*(9*n + d - 1) + e OR x = 1+10*(n - 1) + 9
if (x == 0)

31
src/compressor.h
View File

@ -14,6 +14,13 @@ class CKeyID;
class CPubKey;
class CScriptID;
bool CompressScript(const CScript& script, std::vector<unsigned char> &out);
unsigned int GetSpecialScriptSize(unsigned int nSize);
bool DecompressScript(CScript& script, unsigned int nSize, const std::vector<unsigned char> &out);
uint64_t CompressAmount(uint64_t nAmount);
uint64_t DecompressAmount(uint64_t nAmount);
/** Compact serializer for scripts.
*
* It detects common cases and encodes them much more efficiently.
@ -37,28 +44,13 @@ private:
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:
explicit CScriptCompressor(CScript &scriptIn) : script(scriptIn) { }
template<typename Stream>
void Serialize(Stream &s) const {
std::vector<unsigned char> compr;
if (Compress(compr)) {
if (CompressScript(script, compr)) {
s << CFlatData(compr);
return;
}
@ -72,9 +64,9 @@ public:
unsigned int nSize = 0;
s >> VARINT(nSize);
if (nSize < nSpecialScripts) {
std::vector<unsigned char> vch(GetSpecialSize(nSize), 0x00);
std::vector<unsigned char> vch(GetSpecialScriptSize(nSize), 0x00);
s >> CFlatData(vch);
Decompress(nSize, vch);
DecompressScript(script, nSize, vch);
return;
}
nSize -= nSpecialScripts;
@ -96,9 +88,6 @@ private:
CTxOut &txout;
public:
static uint64_t CompressAmount(uint64_t nAmount);
static uint64_t DecompressAmount(uint64_t nAmount);
explicit CTxOutCompressor(CTxOut &txoutIn) : txout(txoutIn) { }
ADD_SERIALIZE_METHODS;

8
src/test/compress_tests.cpp
View File

@ -25,16 +25,16 @@
BOOST_FIXTURE_TEST_SUITE(compress_tests, BasicTestingSetup)
bool static TestEncode(uint64_t in) {
return in == CTxOutCompressor::DecompressAmount(CTxOutCompressor::CompressAmount(in));
return in == DecompressAmount(CompressAmount(in));
}
bool static TestDecode(uint64_t in) {
return in == CTxOutCompressor::CompressAmount(CTxOutCompressor::DecompressAmount(in));
return in == CompressAmount(DecompressAmount(in));
}
bool static TestPair(uint64_t dec, uint64_t enc) {
return CTxOutCompressor::CompressAmount(dec) == enc &&
CTxOutCompressor::DecompressAmount(enc) == dec;
return CompressAmount(dec) == enc &&
DecompressAmount(enc) == dec;
}
BOOST_AUTO_TEST_CASE(compress_amounts)