context.h

//***************************************************************************
//
// file : bmptk/core/context.h
//
// LICENSE (MIT expat license, copy of bmptk/license.txt)
//
// Copyright (c) 2013 Wouter van Ooijen (wouter@voti.nl)
// 
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE..
//
//***************************************************************************

#ifdef BMPTK_TARGET_win
    #include <iostream>
#else
    namespace std { class ostream; };
#endif

namespace bmptk {

class context {

   unsigned char *bottom;
   
   //
   unsigned char *sp;
   
   friend std::ostream & bmptk::operator<< ( std::ostream &s, const context &st );
   
public:

   constexpr context( unsigned char *bottom, unsigned char *size );
   
   const unsigned int stack_size;
   
   //

   context( void body(), unsigned int stack_size );
   
   //
   unsigned int stack_unused() const;  
   
   //
   unsigned int stack_used() const {
      return stack_size - stack_unused();
   }   
   
   //
   void resume();
};

//
extern context main_context;

//
context * current_context();
   
//
std::ostream & operator<< ( std::ostream &s, const context &st );

}; // namespace bmptk;