Merge #12885: Reduce implementation code inside CScript

54a5a21 [MOVEONLY] Turn CScript::GetOp2 into a function and move to cpp (Pieter Wuille)
6a7456a [MOVEONLY] Move CSCript::FindAndDelete to interpreter (Pieter Wuille)
33a8ecf Delete unused non-const-iterator CSCript::GetOp overloads (Pieter Wuille)
2fb168b Make iterators in CScript::FindAndDelete const (Pieter Wuille)

Pull request description:

  This PR moves `FindAndDelete` and `GetOp2` out of CScript (the first is only used inside the interpreter and moved there, the second does not actually depend on any script specifics and works on any vector). Furthermore, all non-const-iterator versions of GetOp are replaced by const ones, removing a number of methods in the process.

  The longer term goal here is making the script interpreter independent from the CScript representation.

  Note for reviewers: both `FindAndDelete` and `GetScriptOp` are consensus critical.

Tree-SHA512: c4ccf91c0b33c37cff0d474aa8dd2dab25b5b7655e2ed69a9b15e29daf0a67b21d51c23e1defb3a72ec762bd6138de96f69c6db1fb9c1fe1e976e421261aedb7

1 files changed, 30 insertions, 2 deletions

diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index 338e07e24..e0d193fa3 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -250,6 +250,34 @@ bool static CheckMinimalPush(const valtype& data, opcodetype opcode) {
     return true;
 }
 
+int FindAndDelete(CScript& script, const CScript& b)
+{
+    int nFound = 0;
+    if (b.empty())
+        return nFound;
+    CScript result;
+    CScript::const_iterator pc = script.begin(), pc2 = script.begin(), end = script.end();
+    opcodetype opcode;
+    do
+    {
+        result.insert(result.end(), pc2, pc);
+        while (static_cast<size_t>(end - pc) >= b.size() && std::equal(b.begin(), b.end(), pc))
+        {
+            pc = pc + b.size();
+            ++nFound;
+        }
+        pc2 = pc;
+    }
+    while (script.GetOp(pc, opcode));
+
+    if (nFound > 0) {
+        result.insert(result.end(), pc2, end);
+        script = std::move(result);
+    }
+
+    return nFound;
+}
+
 bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror)
 {
     static const CScriptNum bnZero(0);
@@ -891,7 +919,7 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript&
 
                     // Drop the signature in pre-segwit scripts but not segwit scripts
                     if (sigversion == SigVersion::BASE) {
-                        scriptCode.FindAndDelete(CScript(vchSig));
+                        FindAndDelete(scriptCode, CScript(vchSig));
                     }
 
                     if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, sigversion, serror)) {
@@ -955,7 +983,7 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript&
                     {
                         valtype& vchSig = stacktop(-isig-k);
                         if (sigversion == SigVersion::BASE) {
-                            scriptCode.FindAndDelete(CScript(vchSig));
+                            FindAndDelete(scriptCode, CScript(vchSig));
                         }
                     }