From 310b56c936383055c2dd1fd14d56853f576f6038 Mon Sep 17 00:00:00 2001
From: Ingo Berg <2202567+beltoforion@users.noreply.github.com>
Date: Sat, 14 Oct 2023 04:27:06 +0200
Subject: [PATCH] fix for #131: save string buffer with bytecode

---
 include/muParserBytecode.h    | 20 ++++++++++++++++++++
 samples/example1/example1.cpp |  2 +-
 src/muParserBase.cpp          | 10 +++++++++-
 src/muParserBytecode.cpp      |  9 +++++++--
 4 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/include/muParserBytecode.h b/include/muParserBytecode.h
index a6aff2b..bf84dd7 100644
--- a/include/muParserBytecode.h
+++ b/include/muParserBytecode.h
@@ -94,9 +94,18 @@ namespace mu
 		/** \brief Token vector for storing the RPN. */
 		typedef std::vector<SToken> rpn_type;
 
+		/** \brief Type for a vector of strings. */
+		typedef std::vector<string_type> stringbuf_type;
+
 		/** \brief Position in the Calculation array. */
 		unsigned m_iStackPos;
 
+		/** \brief String variable storage. */
+		stringbuf_type m_stringBuffer;
+
+		/** \brief The expression associated with this bytecode. */
+		string_type m_expr;
+
 		/** \brief Maximum size needed for the stack. */
 		std::size_t m_iMaxStackSize;
 
@@ -142,6 +151,17 @@ namespace mu
 				return &m_vRPN[0];
 		}
 
+		void StoreEnvironment(string_type a_expr, stringbuf_type const& a_strBuf)
+		{
+			m_stringBuffer = a_strBuf;
+			m_expr = a_expr;
+		}
+
+		std::tuple<string_type, stringbuf_type> RestoreEnvironment() const
+		{
+			return std::make_tuple(m_expr, m_stringBuffer);
+		}
+
 		void AsciiDump() const;
 	};
 
diff --git a/samples/example1/example1.cpp b/samples/example1/example1.cpp
index 49c3338..5577aa7 100644
--- a/samples/example1/example1.cpp
+++ b/samples/example1/example1.cpp
@@ -475,7 +475,7 @@ static void Calc()
 	parser.SetVarFactory(AddVariable, &parser);
 
 	// You can extract the bytecode of a parsed functions and save it for later use.
-	parser.SetExpr(_T("sin(a)"));
+	parser.SetExpr(_T("sin(a)+strfun2(sVar1, 1 , 2)"));
 	parser.Eval();
 	ParserByteCode bytecode1(parser.GetByteCode());
 
diff --git a/src/muParserBase.cpp b/src/muParserBase.cpp
index 8da035f..b42ac91 100644
--- a/src/muParserBase.cpp
+++ b/src/muParserBase.cpp
@@ -277,7 +277,13 @@ namespace mu
 	/** \brief Restore a previously saved bytecode. */
 	void ParserBase::SetByteCode(const ParserByteCode& a_ByteCode)
 	{
-		m_vRPN.Assign(a_ByteCode);
+		m_vRPN = a_ByteCode;
+
+		// restore expression environment
+		string_type expr;
+		std::tie(expr, m_vStringBuf) = a_ByteCode.RestoreEnvironment();
+		m_pTokenReader->SetFormula(expr);
+
 		m_pParseFormula = &ParserBase::ParseCmdCode;
 	}
 
@@ -1540,12 +1546,14 @@ namespace mu
 
 			if (m_vRPN.GetSize() == 2)
 			{
+				m_vRPN.StoreEnvironment(m_pTokenReader->GetExpr(), m_vStringBuf);
 				m_pParseFormula = &ParserBase::ParseCmdCodeShort;
 				m_vStackBuffer[1] = (this->*m_pParseFormula)();
 				return m_vStackBuffer[1];
 			}
 			else
 			{
+				m_vRPN.StoreEnvironment(m_pTokenReader->GetExpr(), m_vStringBuf);
 				m_pParseFormula = &ParserBase::ParseCmdCode;
 				return (this->*m_pParseFormula)();
 			}
diff --git a/src/muParserBytecode.cpp b/src/muParserBytecode.cpp
index a0b7b9e..1bc61c3 100644
--- a/src/muParserBytecode.cpp
+++ b/src/muParserBytecode.cpp
@@ -49,7 +49,9 @@ namespace mu
 {
 	/** \brief Bytecode default constructor. */
 	ParserByteCode::ParserByteCode()
-		:m_iStackPos(0)
+		: m_iStackPos(0)
+ 		, m_stringBuffer()
+		, m_expr()
 		, m_iMaxStackSize(0)
 		, m_vRPN()
 		, m_bEnableOptimizer(true)
@@ -98,6 +100,9 @@ namespace mu
 		m_vRPN = a_ByteCode.m_vRPN;
 		m_iMaxStackSize = a_ByteCode.m_iMaxStackSize;
 		m_bEnableOptimizer = a_ByteCode.m_bEnableOptimizer;
+		
+		m_stringBuffer = a_ByteCode.m_stringBuffer;
+		m_expr = a_ByteCode.m_expr;
 	}
 
 
@@ -595,7 +600,7 @@ namespace mu
 			case cmFUNC_STR:
 				mu::console() << _T("CALL STRFUNC\t");
 				mu::console() << _T("[ARG:") << std::dec << m_vRPN[i].Fun.argc << _T("]");
-				mu::console() << _T("[IDX:") << std::dec << m_vRPN[i].Fun.idx << _T("]");
+				mu::console() << _T("[IDX:") << std::dec << m_vRPN[i].Fun.idx << _T("=\"") << m_stringBuffer[m_vRPN[i].Fun.idx] << ("\"]");
 				mu::console() << _T("[ADDR: 0x") << std::hex << reinterpret_cast<void*>(m_vRPN[i].Fun.cb._pRawFun) << _T("]");
 				mu::console() << _T("[USERDATA: 0x") << std::hex << reinterpret_cast<void*>(m_vRPN[i].Fun.cb._pUserData) << _T("]");
 				mu::console() << _T("\n");