Method PushState

src/server/angelscript/angelscript/source/as_context.cpp:1389–1453

}

int asCContext::PushState()
{
	// Only allow the state to be pushed when active
	// TODO: Can we support a suspended state too? So the reuse of
	//       the context can be done outside the Execute() call?
	if( m_status != asEXECUTION_ACTIVE )
	{
		// TODO: Write message. Wrong usage
		return asERROR;
	}

	// Allocate space on the callstack for at least two states
	if (m_callStack.GetLength() >= m_callStack.GetCapacity() - 2*CALLSTACK_FRAME_SIZE)
	{
		if (m_engine->ep.maxCallStackSize > 0 && m_callStack.GetLength() >= m_engine->ep.maxCallStackSize*CALLSTACK_FRAME_SIZE)
		{
			// The call stack is too big to grow further
			// If an error occurs, no change to the context should be done
			return asOUT_OF_MEMORY;
		}

		// Allocate space for 10 call states at a time to save time
		m_callStack.AllocateNoConstruct(m_callStack.GetLength() + 10 * CALLSTACK_FRAME_SIZE, true);
	}

	// Push the current script function that is calling the system function
	// This cannot fail, since the memory was already allocated above
	PushCallState();

	// Push the system function too, which will serve both as a marker and
	// informing which system function that created the nested call
	m_callStack.SetLengthNoConstruct(m_callStack.GetLength() + CALLSTACK_FRAME_SIZE);

	// Need to push m_initialFunction as it must be restored later
	asPWORD *tmp = m_callStack.AddressOf() + m_callStack.GetLength() - CALLSTACK_FRAME_SIZE;
	tmp[0] = 0;
	tmp[1] = (asPWORD)m_callingSystemFunction;
	tmp[2] = (asPWORD)m_initialFunction;
	tmp[3] = (asPWORD)m_originalStackPointer;
	tmp[4] = (asPWORD)m_argumentsSize;

	// Need to push the value of registers so they can be restored
	tmp[5] = (asPWORD)asDWORD(m_regs.valueRegister);
	tmp[6] = (asPWORD)asDWORD(m_regs.valueRegister>>32);
	tmp[7] = (asPWORD)m_regs.objectRegister;
	tmp[8] = (asPWORD)m_regs.objectType;

	// Decrease stackpointer to prevent the top value from being overwritten
	m_regs.stackPointer -= 2;

	// Clear the initial function so that Prepare() knows it must do all validations
	m_initialFunction = 0;

	// After this the state should appear as if uninitialized
	m_callingSystemFunction = 0;

	m_regs.objectRegister = 0;
	m_regs.objectType = 0;