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#ifndef CYGONCE_KERNEL_MBOXT_INL
#define CYGONCE_KERNEL_MBOXT_INL
//==========================================================================
//
// mboxt.inl
//
// Mboxt mbox template class implementation
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with eCos; if not, write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. However the source code for this file must still be made available
// in accordance with section (3) of the GNU General Public License.
//
// This exception does not invalidate any other reasons why a work based on
// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
// at http://sources.redhat.com/ecos/ecos-license/
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s): hmt
// Contributors: hmt
// Date: 1998-02-10
// Purpose: Mboxt template implementation
// Description: This file contains the implementations of the mboxt
// template classes.
//
//####DESCRIPTIONEND####
//
//==========================================================================
#include <pkgconf/kernel.h>
#include <cyg/kernel/ktypes.h> // base kernel types
#include <cyg/infra/cyg_trac.h> // tracing macros
#include <cyg/infra/cyg_ass.h> // assertion macros
#include <cyg/kernel/instrmnt.h> // instrumentation
#include <cyg/kernel/mboxt.hxx> // our header
#include <cyg/kernel/thread.inl> // thread inlines
#include <cyg/kernel/sched.inl> // scheduler inlines
#include <cyg/kernel/clock.inl> // clock inlines
// -------------------------------------------------------------------------
// inline function for awakening waiting threads
template <class T, cyg_count32 QUEUE_SIZE>
inline void
Cyg_Mboxt<T,QUEUE_SIZE>::wakeup_waiter( Cyg_ThreadQueue &q )
{
if( !q.empty() ) {
// The queue is non-empty, so grab the next thread and wake it up.
Cyg_Thread *thread = q.dequeue();
CYG_ASSERTCLASS( thread, "Bad thread pointer");
thread->set_wake_reason( Cyg_Thread::DONE );
thread->wake();
CYG_INSTRUMENT_MBOXT(WAKE, this, thread);
}
}
// -------------------------------------------------------------------------
// Constructor
template <class T, cyg_count32 QUEUE_SIZE>
Cyg_Mboxt<T,QUEUE_SIZE>::Cyg_Mboxt()
{
CYG_REPORT_FUNCTION();
base = 0;
count = 0;
}
// -------------------------------------------------------------------------
// Destructor
template <class T, cyg_count32 QUEUE_SIZE>
Cyg_Mboxt<T,QUEUE_SIZE>::~Cyg_Mboxt()
{
CYG_REPORT_FUNCTION();
CYG_ASSERT( 0 == count, "Deleting mboxt with messages");
CYG_ASSERT( get_threadq.empty(), "Deleting mboxt with threads waiting to get");
#ifdef CYGMFN_KERNEL_SYNCH_MBOXT_PUT_CAN_WAIT
CYG_ASSERT( put_threadq.empty(), "Deleting mboxt with threads waiting to put");
#endif
}
// -------------------------------------------------------------------------
// debugging/assert function
#ifdef CYGDBG_USE_ASSERTS
template <class T, cyg_count32 QUEUE_SIZE>
cyg_bool
Cyg_Mboxt<T,QUEUE_SIZE>::check_this(cyg_assert_class_zeal zeal) const
{
CYG_REPORT_FUNCTION();
if ( Cyg_Thread::DESTRUCT == Cyg_Thread::self()->get_wake_reason() )
// then the whole thing is invalid, and we know it.
// so return OK, since this check should NOT make an error.
return true;
// check that we have a non-NULL pointer first
if( this == NULL ) return false;
#if 0 // thread queues do not have checking funcs.
if ( ! get_threadq.check_this( zeal ) ) return false;
#ifdef CYGMFN_KERNEL_SYNCH_MBOXT_PUT_CAN_WAIT
if ( ! put_threadq.check_this( zeal ) ) return false;
#endif
#endif
switch( zeal )
{
case cyg_system_test:
case cyg_extreme:
case cyg_thorough:
case cyg_quick:
case cyg_trivial:
// plenty of scope for fencepost problems here
if ( size < count ) return false;
if ( size <= base ) return false;
if ( 0 > count ) return false;
if ( 0 > base ) return false;
// there was initially a test of the form
// (0 < count && count < size) && ! threadqueue.empty()
// here - ie. there should only be people waiting if the Q is full
// or empty. This is bogus, anyone else might run between a waiter
// being awoken, so there can be a 2nd waiter in the Q and a free
// slot (say) simultaneously.
// Further, we need 2 queues; imagine a 10-slot itemqueue with 25
// attempts to put to it, so 15 sleep. 10 other threads get,
// awakening 10 of the 15 put-sleepers. Another one gets, and
// can't because there is no data there _yet_; it sleeps, and the
// 10 awakened threads cycle through the run queue, each putting,
// the first awakens the get-sleeper, which in turn awakens a
// further put-sleeper.
// This requirement for 2 queue only holds if Ngetters > 2 * Nslots
// or Nputters > 2 * Nslots; if these are both false, one queue
// will suffice. This could be an optimisation for the future -
// wow, 4 bytes.
case cyg_none:
default:
break;
};
return true;
}
#endif
// -------------------------------------------------------------------------
// From here downwards, these are the major functions of the template; if
// being genuinely used as a template they should probably not be inlined.
// If being used to construct a specific class, with explicit functions,
// then they should be. This is controlled by:
#ifdef CYGIMP_MBOXT_INLINE
#define CYG_MBOXT_INLINE inline
#else
#define CYG_MBOXT_INLINE
#endif
// -------------------------------------------------------------------------
// Get an item, or wait for one to arrive
template <class T, cyg_count32 QUEUE_SIZE>
CYG_MBOXT_INLINE cyg_bool
Cyg_Mboxt<T,QUEUE_SIZE>::get( T &ritem )
{
CYG_REPORT_FUNCTION();
cyg_bool result = true;
Cyg_Thread *self = Cyg_Thread::self();
// Prevent preemption
Cyg_Scheduler::lock();
CYG_ASSERTCLASS( this, "Bad this pointer");
CYG_INSTRUMENT_MBOXT(GET, this, count);
// Loop while the mboxt is empty, sleeping each time around
// the loop. This copes with the possibility of a higher priority
// thread grabbing the message between the wakeup in unlock() and
// this thread actually starting.
while( result && (0 == count) ) {
self->set_sleep_reason( Cyg_Thread::WAIT );
self->sleep();
get_threadq.enqueue( self );
CYG_INSTRUMENT_MBOXT(WAIT, this, count);
// Allow other threads to run
Cyg_Scheduler::reschedule();
CYG_ASSERTCLASS( this, "Bad this pointer");
switch( self->get_wake_reason() )
{
case Cyg_Thread::DESTRUCT:
case Cyg_Thread::BREAK:
result = false;
break;
case Cyg_Thread::EXIT:
self->exit();
break;
default:
break;
}
}
if ( result ) {
CYG_INSTRUMENT_MBOXT(GOT, this, count);
ritem = itemqueue[ (count--, base++) ];
CYG_ASSERT( 0 <= count, "Count went -ve" );
CYG_ASSERT( size >= base, "Base overflow" );
if ( size <= base )
base = 0;
#ifdef CYGMFN_KERNEL_SYNCH_MBOXT_PUT_CAN_WAIT
wakeup_waiter( put_threadq );
#endif
}
// Unlock the scheduler and maybe switch threads
Cyg_Scheduler::unlock();
CYG_ASSERTCLASS( this, "Bad this pointer");
CYG_REPORT_RETVAL( result );
return result;
}
// -------------------------------------------------------------------------
// Try to get an item with an absolute timeout and return success.
#ifdef CYGFUN_KERNEL_THREADS_TIMER
template <class T, cyg_count32 QUEUE_SIZE>
CYG_MBOXT_INLINE cyg_bool
Cyg_Mboxt<T,QUEUE_SIZE>::get( T &ritem, cyg_tick_count abs_timeout )
{
CYG_REPORT_FUNCTION();
cyg_bool result = true;
Cyg_Thread *self = Cyg_Thread::self();
// Prevent preemption
Cyg_Scheduler::lock();
CYG_ASSERTCLASS( this, "Bad this pointer");
CYG_INSTRUMENT_MBOXT(GET, this, count);
// Set the timer _once_ outside the loop.
self->set_timer( abs_timeout, Cyg_Thread::TIMEOUT );
// If the timeout is in the past, the wake reason will have been
// set to something other than NONE already. Set the result false
// to force an immediate return.
if( self->get_wake_reason() != Cyg_Thread::NONE )
result = false;
// Loop while the mboxt is empty, sleeping each time around the loop.
// This copes with the possibility of a higher priority thread grabbing
// the message between the wakeup in put()&c and this thread actually
// starting.
while ( result && (0 == count) ) {
// must reset the sleep reason every time
self->set_sleep_reason( Cyg_Thread::TIMEOUT );
self->sleep();
get_threadq.enqueue( self );
CYG_INSTRUMENT_MBOXT(WAIT, this, count);
// Allow other threads to run
Cyg_Scheduler::reschedule();
CYG_ASSERTCLASS( this, "Bad this pointer");
switch( self->get_wake_reason() )
{
case Cyg_Thread::TIMEOUT:
result = false;
CYG_INSTRUMENT_MBOXT(TIMEOUT, this, count);
break;
case Cyg_Thread::DESTRUCT:
case Cyg_Thread::BREAK:
result = false;
break;
case Cyg_Thread::EXIT:
self->exit();
break;
default:
break;
}
}
// clear the timer; if it actually fired, no worries.
self->clear_timer();
if ( result ) {
CYG_INSTRUMENT_MBOXT(GOT, this, count);
ritem = itemqueue[ (count--, base++) ];
CYG_ASSERT( 0 <= count, "Count went -ve" );
CYG_ASSERT( size >= base, "Base overflow" );
if ( size <= base )
base = 0;
#ifdef CYGMFN_KERNEL_SYNCH_MBOXT_PUT_CAN_WAIT
wakeup_waiter( put_threadq );
#endif
}
// Unlock the scheduler and maybe switch threads
Cyg_Scheduler::unlock();
CYG_ASSERTCLASS( this, "Bad this pointer");
CYG_REPORT_RETVAL( result );
return result;
}
#endif // CYGFUN_KERNEL_THREADS_TIMER
// -------------------------------------------------------------------------
// Try to get an item and return success.
template <class T, cyg_count32 QUEUE_SIZE>
CYG_MBOXT_INLINE cyg_bool
Cyg_Mboxt<T,QUEUE_SIZE>::tryget( T &ritem )
{
CYG_REPORT_FUNCTION();
CYG_ASSERTCLASS( this, "Bad this pointer");
// Prevent preemption
Cyg_Scheduler::lock();
CYG_INSTRUMENT_MBOXT(TRY, this, count);
cyg_bool result = ( 0 < count );
// If the mboxt is not empty, grab an item and return it.
if ( result ) {
ritem = itemqueue[ (count--, base++) ];
CYG_ASSERT( 0 <= count, "Count went -ve" );
CYG_ASSERT( size >= base, "Base overflow" );
if ( size <= base )
base = 0;
#ifdef CYGMFN_KERNEL_SYNCH_MBOXT_PUT_CAN_WAIT
wakeup_waiter( put_threadq );
#endif
}
// Unlock the scheduler and maybe switch threads
Cyg_Scheduler::unlock();
return result;
}
// -------------------------------------------------------------------------
// get next item without removing it
template <class T, cyg_count32 QUEUE_SIZE>
CYG_MBOXT_INLINE cyg_bool
Cyg_Mboxt<T,QUEUE_SIZE>::peek_item( T &ritem )
{
CYG_REPORT_FUNCTION();
CYG_ASSERTCLASS( this, "Bad this pointer");
// Prevent preemption
Cyg_Scheduler::lock();
CYG_INSTRUMENT_MBOXT(TRY, this, count);
cyg_bool result = ( 0 < count );
// If the mboxt is not empty, grab an item and return it.
if ( result )
ritem = itemqueue[ base ];
// Unlock the scheduler and maybe switch threads
Cyg_Scheduler::unlock();
return result;
}
// -------------------------------------------------------------------------
// Put an item in the queue; wait if full.
#ifdef CYGMFN_KERNEL_SYNCH_MBOXT_PUT_CAN_WAIT
template <class T, cyg_count32 QUEUE_SIZE>
CYG_MBOXT_INLINE cyg_bool
Cyg_Mboxt<T,QUEUE_SIZE>::put( const T item )
{
CYG_REPORT_FUNCTION();
cyg_bool result = true;
Cyg_Thread *self = Cyg_Thread::self();
// Prevent preemption
Cyg_Scheduler::lock();
CYG_INSTRUMENT_MBOXT(PUT, this, count);
CYG_ASSERTCLASS( this, "Bad this pointer");
while ( result && (size == count) ) {
self->set_sleep_reason( Cyg_Thread::WAIT );
self->sleep();
put_threadq.enqueue( self );
CYG_INSTRUMENT_MBOXT(WAIT, this, count);
// Allow other threads to run
Cyg_Scheduler::reschedule();
CYG_ASSERTCLASS( this, "Bad this pointer");
switch( self->get_wake_reason() )
{
case Cyg_Thread::DESTRUCT:
case Cyg_Thread::BREAK:
result = false;
break;
case Cyg_Thread::EXIT:
self->exit();
break;
default:
break;
}
}
if ( result ) {
cyg_count32 in = base + (count++);
if ( size <= in )
in -= size;
CYG_ASSERT( size > in, "in overflow" );
CYG_ASSERT( 0 <= in, "in overflow" );
CYG_ASSERT( size >= count, "count overflow" );
itemqueue[ in ] = item;
wakeup_waiter( get_threadq );
}
CYG_ASSERTCLASS( this, "Bad this pointer");
// Unlock the scheduler and maybe switch threads
Cyg_Scheduler::unlock();
CYG_REPORT_RETVAL( result );
return result;
}
// -------------------------------------------------------------------------
// Put an item in the queue; wait if full, with an absolute timeout;
// return success.
#ifdef CYGFUN_KERNEL_THREADS_TIMER
template <class T, cyg_count32 QUEUE_SIZE>
CYG_MBOXT_INLINE cyg_bool
Cyg_Mboxt<T,QUEUE_SIZE>::put( const T item, cyg_tick_count abs_timeout )
{
CYG_REPORT_FUNCTION();
cyg_bool result = true;
Cyg_Thread *self = Cyg_Thread::self();
// Prevent preemption
Cyg_Scheduler::lock();
CYG_INSTRUMENT_MBOXT(PUT, this, count);
CYG_ASSERTCLASS( this, "Bad this pointer");
// Set the timer _once_ outside the loop.
self->set_timer( abs_timeout, Cyg_Thread::TIMEOUT );
// If the timeout is in the past, the wake reason will have been
// set to something other than NONE already. Set the result false
// to force an immediate return.
if( self->get_wake_reason() != Cyg_Thread::NONE )
result = false;
// Loop while the mboxt is full, sleeping each time around the loop.
// This copes with the possibility of a higher priority thread filling
// the empty slot between the wakeup in get()&c and this thread
// actually starting.
while ( result && (size == count) ) {
// must reset the sleep reason every time
self->set_sleep_reason( Cyg_Thread::TIMEOUT );
self->sleep();
put_threadq.enqueue( self );
CYG_INSTRUMENT_MBOXT(WAIT, this, count);
// Allow other threads to run
Cyg_Scheduler::reschedule();
CYG_ASSERTCLASS( this, "Bad this pointer");
switch( self->get_wake_reason() )
{
case Cyg_Thread::TIMEOUT:
result = false;
CYG_INSTRUMENT_MBOXT(TIMEOUT, this, count);
break;
case Cyg_Thread::DESTRUCT:
case Cyg_Thread::BREAK:
result = false;
break;
case Cyg_Thread::EXIT:
self->exit();
break;
default:
break;
}
}
// clear the timer; if it actually fired, no worries.
self->clear_timer();
if ( result ) {
cyg_count32 in = base + (count++);
if ( size <= in )
in -= size;
CYG_ASSERT( size > in, "in overflow" );
CYG_ASSERT( 0 <= in, "in overflow" );
CYG_ASSERT( size >= count, "count overflow" );
itemqueue[ in ] = item;
wakeup_waiter( get_threadq );
}
CYG_ASSERTCLASS( this, "Bad this pointer");
// Unlock the scheduler and maybe switch threads
Cyg_Scheduler::unlock();
CYG_REPORT_RETVAL( result );
return result;
}
#endif // CYGFUN_KERNEL_THREADS_TIMER
#endif // CYGMFN_KERNEL_SYNCH_MBOXT_PUT_CAN_WAIT
// -------------------------------------------------------------------------
// Try to put an item in the queue and return success; queue may be full.
template <class T, cyg_count32 QUEUE_SIZE>
CYG_MBOXT_INLINE cyg_bool
Cyg_Mboxt<T,QUEUE_SIZE>::tryput( const T item )
{
CYG_REPORT_FUNCTION();
// Prevent preemption
Cyg_Scheduler::lock();
CYG_INSTRUMENT_MBOXT(PUT, this, count);
CYG_ASSERTCLASS( this, "Bad this pointer");
if ( size == count ) {
Cyg_Scheduler::unlock(); // unlock, maybe switch threads
return false; // the mboxt is full
}
cyg_count32 in = base + (count++);
if ( size <= in )
in -= size;
CYG_ASSERT( size > in, "in overflow" );
CYG_ASSERT( 0 <= in, "in overflow" );
CYG_ASSERT( size >= count, "count overflow" );
itemqueue[ in ] = item;
CYG_ASSERTCLASS( this, "Bad this pointer");
wakeup_waiter( get_threadq );
// Unlock the scheduler and maybe switch threads
Cyg_Scheduler::unlock();
return true;
}
// -------------------------------------------------------------------------
#endif // ifndef CYGONCE_KERNEL_MBOXT_INL
// EOF mboxt.inl
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