Merge bitcoin#19852: refactor: Avoid duplicate map lookup in ScriptTo…

…AsmStr

ac2ff4f refactor: Avoid duplicate map lookup in ScriptToAsmStr (João Barbosa)

Pull request description:

  Simple change that avoids a duplicate (unnecessary) `mapSigHashTypes` lookup.

ACKs for top commit:
  laanwj:
    re-ACK ac2ff4f

Tree-SHA512: 7e7f5af51c1acd7a42af273e5ee5e2faddd250ba8b8f63ccb3172d95f153ae391b2816b79564b856571af52dc2a767b5736a5d10ffb5cd2c540cd9832bf86419

src/core_write.cpp

@@ -113,8 +113,9 @@ std::string ScriptToAsmStr(const CScript& script, const bool fAttemptSighashDeco
                     // checks in CheckSignatureEncoding.
                     if (CheckSignatureEncoding(vch, SCRIPT_VERIFY_STRICTENC, nullptr)) {
                         const unsigned char chSigHashType = vch.back();
-                        if (mapSigHashTypes.count(chSigHashType)) {
-                            strSigHashDecode = "[" + mapSigHashTypes.find(chSigHashType)->second + "]";
+                        const auto it = mapSigHashTypes.find(chSigHashType);
+                        if (it != mapSigHashTypes.end()) {
+                            strSigHashDecode = "[" + it->second + "]";
                             vch.pop_back(); // remove the sighash type byte. it will be replaced by the decode.
                         }
                     }