BASIC : Use a vector to store the go sub stack.

Change-Id: I80987f3f7c036279a8292a7fbbd2dcd232196226
Reviewed-on: https://gerrit.libreoffice.org/23753
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Arnaud Versini <arnaud.versini@libreoffice.org>

2 files changed, 21 insertions, 40 deletions

diff --git a/basic/source/inc/runtime.hxx b/basic/source/inc/runtime.hxx
index ed4cf423558e..6d1a8a01f577 100644
--- a/basic/source/inc/runtime.hxx
+++ b/basic/source/inc/runtime.hxx
@@ -41,7 +41,7 @@ class SbiInstance;                  // active StarBASIC process
 class SbiRuntime;                   // active StarBASIC procedure instance
 
 struct SbiArgvStack;                // Argv stack element
-struct SbiGosubStack;               // GOSUB stack element
+struct SbiGosub;                    // GOSUB stack element
 class  SbiImage;                    // Code-Image
 class  SbiIoSystem;
 class  SbiDdeControl;
@@ -89,12 +89,6 @@ struct SbiForStack {                // for/next stack:
 
 #define MAXRECURSION 500
 
-struct SbiGosubStack {              // GOSUB-Stack:
-    SbiGosubStack* pNext;           // Chain
-    const sal_uInt8* pCode;         // Return-Pointer
-    sal_uInt16 nStartForLvl;        // #118235: For Level in moment of gosub
-};
-
 enum class SbAttributes {
     NONE          = 0x0000,
     READONLY      = 0x0001,
@@ -237,10 +231,8 @@ class SbiRuntime
     SbxVariableRef xDummyVar;       // substitute for variables that weren't found
     SbxVariable* mpExtCaller;       // Caller ( external - e.g. button name, shape, range object etc. - only in vba mode )
     SbiArgvStack*  pArgvStk;        // ARGV-Stack
-    SbiGosubStack* pGosubStk;       // GOSUB stack
     SbiForStack*   pForStk;         // FOR/NEXT-Stack
     sal_uInt16        nExprLvl;         // depth of the expr-stack
-    sal_uInt16        nGosubLvl;        // to prevent dead-recursions
     sal_uInt16        nForLvl;          // #118235: Maintain for level
     const sal_uInt8*   pCode;            // current Code-Pointer
     const sal_uInt8*   pStmnt;           // beginning of the last statement
@@ -265,6 +257,8 @@ class SbiRuntime
     sal_uInt32    m_nLastTime;
 
     std::vector<SbxVariableRef>  aRefSaved; // #74254 save temporary references
+    std::vector<SbiGosub>   pGosubStk; // GOSUB stack
+
 
     SbxVariable* FindElement
     ( SbxObject* pObj, sal_uInt32 nOp1, sal_uInt32 nOp2, SbError, bool bLocal, bool bStatic = false );
@@ -279,7 +273,6 @@ class SbiRuntime
 
     void PushGosub( const sal_uInt8* );
     void PopGosub();
-    void ClearGosubStack();
 
     void PushArgv();
     void PopArgv();
diff --git a/basic/source/runtime/runtime.cxx b/basic/source/runtime/runtime.cxx
index 412f5693f3a8..80815fe279e9 100644
--- a/basic/source/runtime/runtime.cxx
+++ b/basic/source/runtime/runtime.cxx
@@ -111,13 +111,23 @@ bool StarBASIC::isVBAEnabled()
     return false;
 }
 
-
 struct SbiArgvStack {                   // Argv stack:
     SbiArgvStack*  pNext;               // Stack Chain
     SbxArrayRef    refArgv;             // Argv
     short nArgc;                        // Argc
 };
 
+#define MAXRECURSION 500 //to prevent dead-recursions
+
+struct SbiGosub {              // GOSUB-Stack:
+    const sal_uInt8* pCode;         // Return-Pointer
+    sal_uInt16 nStartForLvl;        // #118235: For Level in moment of gosub
+
+    SbiGosub(const sal_uInt8* pCode_, sal_uInt16 nStartForLvl_) :
+        pCode(pCode_),
+        nStartForLvl(nStartForLvl_) {}
+};
+
 SbiRuntime::pStep0 SbiRuntime::aStep0[] = { // all opcodes without operands
     &SbiRuntime::StepNOP,
     &SbiRuntime::StepEXP,
@@ -568,7 +578,6 @@ SbiRuntime::SbiRuntime( SbModule* pm, SbMethod* pe, sal_uInt32 nStart )
     nFlags    = pe ? pe->GetDebugFlags() : 0;
     pIosys    = pInst->GetIoSystem();
     pArgvStk  = nullptr;
-    pGosubStk = nullptr;
     pForStk   = nullptr;
     pError    = nullptr;
     pErrCode  =
@@ -587,7 +596,6 @@ SbiRuntime::SbiRuntime( SbModule* pm, SbMethod* pe, sal_uInt32 nStart )
     nExprLvl  = 0;
     nArgc     = 0;
     nError    = 0;
-    nGosubLvl = 0;
     nForLvl   = 0;
     nOps      = 0;
     refExprStk = new SbxArray;
@@ -597,7 +605,6 @@ SbiRuntime::SbiRuntime( SbModule* pm, SbMethod* pe, sal_uInt32 nStart )
 
 SbiRuntime::~SbiRuntime()
 {
-    ClearGosubStack();
     ClearArgvStack();
     ClearForStack();
 }
@@ -1049,43 +1056,24 @@ void SbiRuntime::TOSMakeTemp()
 // the GOSUB-stack collects return-addresses for GOSUBs
 void SbiRuntime::PushGosub( const sal_uInt8* pc )
 {
-    if( ++nGosubLvl > MAXRECURSION )
+    if( pGosubStk.size() >= MAXRECURSION )
     {
         StarBASIC::FatalError( ERRCODE_BASIC_STACK_OVERFLOW );
     }
-    SbiGosubStack* p = new SbiGosubStack;
-    p->pCode  = pc;
-    p->pNext  = pGosubStk;
-    p->nStartForLvl = nForLvl;
-    pGosubStk = p;
+    pGosubStk.emplace_back(pc, nForLvl);
 }
 
 void SbiRuntime::PopGosub()
 {
-    if( !pGosubStk )
+    if( pGosubStk.empty() )
     {
         Error( ERRCODE_BASIC_NO_GOSUB );
     }
     else
     {
-        SbiGosubStack* p = pGosubStk;
-        pCode = p->pCode;
-        pGosubStk = p->pNext;
-        delete p;
-        nGosubLvl--;
-    }
-}
-
-
-void SbiRuntime::ClearGosubStack()
-{
-    SbiGosubStack* p;
-    while(( p = pGosubStk ) != nullptr )
-    {
-        pGosubStk = p->pNext;
-        delete p;
+        pCode = pGosubStk.back().pCode;
+        pGosubStk.pop_back();
     }
-    nGosubLvl = 0;
 }
 
 // the Argv-stack collects current argument-vectors
@@ -4237,9 +4225,9 @@ void SbiRuntime::StepSTMNT( sal_uInt32 nOp1, sal_uInt32 nOp2 )
     {
         // (there's a difference here in case of a jump out of a loop)
         sal_uInt16 nExspectedForLevel = static_cast<sal_uInt16>( nOp2 / 0x100 );
-        if( pGosubStk )
+        if( !pGosubStk.empty() )
         {
-            nExspectedForLevel = nExspectedForLevel + pGosubStk->nStartForLvl;
+            nExspectedForLevel = nExspectedForLevel + pGosubStk.back().nStartForLvl;
         }
 
         // if the actual for-level is too small it'd jump out