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Merge #7907: Optimize and Cleanup CScript::FindAndDelete

d1d7775 Improve worst-case behavior of CScript::FindAndDelete (Patrick Strateman)
e2a30bc Unit test for CScript::FindAndDelete (Gavin Andresen)
c0f660c Replace c-style cast with c++ style static_cast. (Patrick Strateman)
ec9ad5f Replace memcmp with std::equal in CScript::FindAndDelete (Patrick Strateman)
0.13
Wladimir J. van der Laan 9 years ago
parent
commit
006cdf64dc
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  1. 15
      src/script/script.h
  2. 117
      src/test/script_tests.cpp

15
src/script/script.h

@ -573,17 +573,26 @@ public: @@ -573,17 +573,26 @@ public:
int nFound = 0;
if (b.empty())
return nFound;
iterator pc = begin();
CScript result;
iterator pc = begin(), pc2 = begin();
opcodetype opcode;
do
{
while (end() - pc >= (long)b.size() && memcmp(&pc[0], &b[0], b.size()) == 0)
result.insert(result.end(), pc2, pc);
while (static_cast<size_t>(end() - pc) >= b.size() && std::equal(b.begin(), b.end(), pc))
{
pc = erase(pc, pc + b.size());
pc = pc + b.size();
++nFound;
}
pc2 = pc;
}
while (GetOp(pc, opcode));
if (nFound > 0) {
result.insert(result.end(), pc2, end());
*this = result;
}
return nFound;
}
int Find(opcodetype op) const

117
src/test/script_tests.cpp

@ -1051,4 +1051,121 @@ BOOST_AUTO_TEST_CASE(script_GetScriptAsm) @@ -1051,4 +1051,121 @@ BOOST_AUTO_TEST_CASE(script_GetScriptAsm)
BOOST_CHECK_EQUAL(derSig + "83 " + pubKey, ScriptToAsmStr(CScript() << ToByteVector(ParseHex(derSig + "83")) << vchPubKey));
}
static CScript
ScriptFromHex(const char* hex)
{
std::vector<unsigned char> data = ParseHex(hex);
return CScript(data.begin(), data.end());
}
BOOST_AUTO_TEST_CASE(script_FindAndDelete)
{
// Exercise the FindAndDelete functionality
CScript s;
CScript d;
CScript expect;
s = CScript() << OP_1 << OP_2;
d = CScript(); // delete nothing should be a no-op
expect = s;
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 0);
BOOST_CHECK(s == expect);
s = CScript() << OP_1 << OP_2 << OP_3;
d = CScript() << OP_2;
expect = CScript() << OP_1 << OP_3;
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 1);
BOOST_CHECK(s == expect);
s = CScript() << OP_3 << OP_1 << OP_3 << OP_3 << OP_4 << OP_3;
d = CScript() << OP_3;
expect = CScript() << OP_1 << OP_4;
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 4);
BOOST_CHECK(s == expect);
s = ScriptFromHex("0302ff03"); // PUSH 0x02ff03 onto stack
d = ScriptFromHex("0302ff03");
expect = CScript();
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 1);
BOOST_CHECK(s == expect);
s = ScriptFromHex("0302ff030302ff03"); // PUSH 0x2ff03 PUSH 0x2ff03
d = ScriptFromHex("0302ff03");
expect = CScript();
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 2);
BOOST_CHECK(s == expect);
s = ScriptFromHex("0302ff030302ff03");
d = ScriptFromHex("02");
expect = s; // FindAndDelete matches entire opcodes
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 0);
BOOST_CHECK(s == expect);
s = ScriptFromHex("0302ff030302ff03");
d = ScriptFromHex("ff");
expect = s;
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 0);
BOOST_CHECK(s == expect);
// This is an odd edge case: strip of the push-three-bytes
// prefix, leaving 02ff03 which is push-two-bytes:
s = ScriptFromHex("0302ff030302ff03");
d = ScriptFromHex("03");
expect = CScript() << ParseHex("ff03") << ParseHex("ff03");
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 2);
BOOST_CHECK(s == expect);
// Byte sequence that spans multiple opcodes:
s = ScriptFromHex("02feed5169"); // PUSH(0xfeed) OP_1 OP_VERIFY
d = ScriptFromHex("feed51");
expect = s;
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 0); // doesn't match 'inside' opcodes
BOOST_CHECK(s == expect);
s = ScriptFromHex("02feed5169"); // PUSH(0xfeed) OP_1 OP_VERIFY
d = ScriptFromHex("02feed51");
expect = ScriptFromHex("69");
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 1);
BOOST_CHECK(s == expect);
s = ScriptFromHex("516902feed5169");
d = ScriptFromHex("feed51");
expect = s;
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 0);
BOOST_CHECK(s == expect);
s = ScriptFromHex("516902feed5169");
d = ScriptFromHex("02feed51");
expect = ScriptFromHex("516969");
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 1);
BOOST_CHECK(s == expect);
s = CScript() << OP_0 << OP_0 << OP_1 << OP_1;
d = CScript() << OP_0 << OP_1;
expect = CScript() << OP_0 << OP_1; // FindAndDelete is single-pass
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 1);
BOOST_CHECK(s == expect);
s = CScript() << OP_0 << OP_0 << OP_1 << OP_0 << OP_1 << OP_1;
d = CScript() << OP_0 << OP_1;
expect = CScript() << OP_0 << OP_1; // FindAndDelete is single-pass
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 2);
BOOST_CHECK(s == expect);
// Another weird edge case:
// End with invalid push (not enough data)...
s = ScriptFromHex("0003feed");
d = ScriptFromHex("03feed"); // ... can remove the invalid push
expect = ScriptFromHex("00");
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 1);
BOOST_CHECK(s == expect);
s = ScriptFromHex("0003feed");
d = ScriptFromHex("00");
expect = ScriptFromHex("03feed");
BOOST_CHECK_EQUAL(s.FindAndDelete(d), 1);
BOOST_CHECK(s == expect);
}
BOOST_AUTO_TEST_SUITE_END()

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