stack.c

用c++包装好的线程库,直接拿来使用,提高效率.

//
// This file is part of the C++ threads library.
//
// Copyright (C) 2001 Orn E. Hansen

#include "thread.h"
#include "exception.h"
#include "stack.h"

#include "cloning.h"

#include <cerrno>
#include <cstring>

#include <iostream.h>

extern "C" {

#  include <malloc.h>

};

#if defined(_ARCH_PPC)
#   define THREADS_SP    JB_GPR1
#else
#   define THREADS_SP    JB_SP
#endif

namespace cpp_threads {

  ThreadStack::ThreadStack(int p_size)
    {
      _have_context = false;
      _saved        = 0;
      if( p_size <= 0 )
	p_size = 8*4096;
      _sp.size  = p_size;
      _sp.stack = new char[p_size];
      if( _sp.stack == 0 )
	exception::fatal(ENOMEM);
    }
  
  ThreadStack::~ThreadStack()
    {
      delete _sp.stack;
      if( _have_context && _saved )
	delete _saved;
    }

  bool 
  ThreadStack::getcontext()
  {
    int x;

    _have_context = false;
    if( _saved )
      delete _saved;
    if( (x = setjmp(_context)) == 0 ) {
      int size = (int)top() -  _context->__jmpbuf[THREADS_SP];

      _pos = &_sp.stack[_sp.size - size - 1];
      _saved = new char[size+1];
      if( _saved ) {
	_have_context = true;
	memcpy(_saved,_pos,size);
      }
    } else {
      ThreadStack *ts = (ThreadStack *)x;
      int size = (int)ts->top() - (int)ts->stack_pos();

      memcpy(ts->stack_pos(),ts->saved_stack(),size);
      return true;
    }
    return false;
  }

  void
  ThreadStack::setcontext()
  {
    if( _have_context )
      longjmp(_context,(int)this);
  }

  void *
  ThreadStack::stack_pos()
  {
    return _pos;
  }

  void *
  ThreadStack::saved_stack()
  {
    return _saved;
  }

  void *ThreadStack::top()
  {
    return (void *)(_sp.stack + _sp.size - 1);
  }

  ThreadStack::operator struct cppThreadStack()
  {
    return _sp;
  }

  ThreadStack::operator struct cppThreadStack *()
  {
    return &_sp;
  }

};