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// CPPParserSymPragma.cpp: Process #pragmas that are interesting,
// which is currently:
//       #pragma pack(...)

#include "CPPParserSym.h"
#include "CPPSymTable.h"

///////////////////////////////////////////////////////////////////////
// HandlePragma:  Process a #pragma directive
// Inputs:
//    None explicitly, but uses LT(i), where LT(1) is assumed to be
//    positioned at the PND_PRAGMA token
// Outputs: none
// Return: none
///////////////////////////////////////////////////////////////////////
// virtual 
void 
CPPParserSym::HandlePragma()
{
   JLStr pragmaText = LT(2)->getText();

   if (GetOption(OptPragmaMSPacking) && pragmaText == "pack")
   {
      HandleMSPacking();
   }
}


///////////////////////////////////////////////////////////////////////
// HandleMSPacking:  Process MS-specific packing pragma
// #pragma pack is one of the following forms, where nnn is an
// integer and id is an identifier
//     #pragma pack()
//     #pragma pack(nnn)
//     #pragma pack(push)
//     #pragma pack(push, nnn)
//     #pragma pack(push, id)
//     #pragma pack(push, id, nnn)
//     #pragma pack(pop)
//     #pragma pack(pop, id)
//
// Inputs:
//    None explicitly, but uses LT(i), where LT(1) is assumed to be
//    positioned at the PND_PRAGMA token
// Outputs: none
// Return: none
///////////////////////////////////////////////////////////////////////
void
CPPParserSym::HandleMSPacking()
{
   bool doPush = false;

   int idx = 3;
   // The next token must be a "("
   if (LT(idx)->getType() != TOK_LPAREN)
   {
      ReportError("Expected '(' after #pragma pack", LT(idx));
      return;
   }
   idx++;

   switch (LT(idx)->getType())
   {
      case TOK_RPAREN:
      {
         // #pragma pack()   - restore default packing
         symTable->SetDefaultPacking();
         break;
      }
   
      case TOK_DECIMALINT:
      {
         // #pragma pack(nnn)
         int newPacking = atoi(LT(idx)->getText());
         if (
            newPacking != 1 && newPacking != 2 &&
            newPacking != 4 && newPacking != 8 &&
            newPacking != 16
         )
         {
            ReportError(JLStr("Invalid packing value: ") + LT(idx)->getText(), LT(idx));
            return;
         }

         idx++;
         // Must have a closing ")"
         if (LT(idx)->getType() != TOK_RPAREN)
         {
            ReportError("Expected ')' after '#pragma pack(nnn' ", LT(idx));
            return;
         }

         symTable->SetPacking(newPacking);
         break;
      }

      case TOK_ID:
      {
         // Must be 'push' or 'pop'
         if (strcmp(LT(idx)->getText(), "push") == 0)
         {
            doPush = true;
         } else if (strcmp(LT(idx)->getText(), "pop") != 0)
         {
            ReportError("Expected 'push' or 'pop' after '#pragma pack(' ", LT(idx));
            return;
         }
         idx++;

         // If the next thing is 'comma identifier', skip it
         if (LT(idx)->getType() == TOK_COMMA && LT(idx+1)->getType() == TOK_ID)
         {
            idx += 2;
         }

         if (doPush)
         {
            bool hasNewPacking = false;
            int newPacking;

            // Optional 'comma integer' for push
            if (LT(idx)->getType() == TOK_COMMA && LT(idx+1)->getType()== TOK_DECIMALINT)
            {
               hasNewPacking = true;             
               idx++;
               newPacking = atoi(LT(idx)->getText());
               if (
                  newPacking != 1 && newPacking != 2 &&
                  newPacking != 4 && newPacking != 8 &&
                  newPacking != 16
               )
               {
                  ReportError(JLStr("Invalid packing value: ") + LT(idx)->getText(), LT(idx));
                  return;
               }
               idx++;
            }

            // Must have a closing ")"
            if (LT(idx)->getType() != TOK_RPAREN)
            {
               ReportError("Expected ')' after '#pragma pack(push,integer' ", LT(idx));
               return;
            }

            // Push the current packing value
            symTable->PushPacking(newPacking);

         } else {
            // pop
            if (symTable->GetPackingStackSize() < 2)
            {
               ReportError("'#pragma pack(pop' not matched with '#pragma pack(push'", LT(1));
               return;
            }

            // Must have a closing ")"
            if (LT(idx)->getType() != TOK_RPAREN)
            {
               ReportError("Expected ')' after '#pragma pack(pop' ", LT(idx));
               return;
            }

            symTable->PopPacking();
         }
         break;
      }

      default:
         ReportError("Expected 'push', 'pop', or integer after '#pragma pack(' ", LT(idx));
         return;
   }

   idx++;
   // Must not have more tokens
   if (LT(idx)->getType() != TOK_PRAGMA_END)
   {
      ReportError("Unexpected tokens after '#pragma pack...' ", LT(idx));
      return;
   }
}