Exemplo n.º 1
0
bool _CORE_message_queue_Initialize(
  CORE_message_queue_Control    *the_message_queue,
  CORE_message_queue_Attributes *the_message_queue_attributes,
  uint32_t                       maximum_pending_messages,
  size_t                         maximum_message_size
)
{
  size_t message_buffering_required = 0;
  size_t allocated_message_size;

  the_message_queue->maximum_pending_messages   = maximum_pending_messages;
  the_message_queue->number_of_pending_messages = 0;
  the_message_queue->maximum_message_size       = maximum_message_size;
  _CORE_message_queue_Set_notify( the_message_queue, NULL, NULL );

  allocated_message_size = maximum_message_size;

  /* 
   * Check if allocated_message_size is aligned to uintptr-size boundary. 
   * If not, it will increase allocated_message_size to multiplicity of pointer
   * size.
   */
  if (allocated_message_size & (sizeof(uintptr_t) - 1)) {
    allocated_message_size += sizeof(uintptr_t);
    allocated_message_size &= ~(sizeof(uintptr_t) - 1);
  }

  /* 
   * Check for an overflow. It can occur while increasing allocated_message_size
   * to multiplicity of uintptr_t above.
   */
  if (allocated_message_size < maximum_message_size)
    return false;

  /*
   *  Calculate how much total memory is required for message buffering and
   *  check for overflow on the multiplication.
   */
  if ( !size_t_mult32_with_overflow(
        (size_t) maximum_pending_messages,
        allocated_message_size + sizeof(CORE_message_queue_Buffer_control),
        &message_buffering_required ) ) 
    return false;

  /*
   *  Attempt to allocate the message memory
   */
  the_message_queue->message_buffers = (CORE_message_queue_Buffer *)
     _Workspace_Allocate( message_buffering_required );

  if (the_message_queue->message_buffers == 0)
    return false;

  /*
   *  Initialize the pool of inactive messages, pending messages,
   *  and set of waiting threads.
   */
  _Chain_Initialize (
    &the_message_queue->Inactive_messages,
    the_message_queue->message_buffers,
    (size_t) maximum_pending_messages,
    allocated_message_size + sizeof( CORE_message_queue_Buffer_control )
  );

  _Chain_Initialize_empty( &the_message_queue->Pending_messages );

  _Thread_queue_Initialize(
    &the_message_queue->Wait_queue,
    _CORE_message_queue_Is_priority( the_message_queue_attributes ) ?
       THREAD_QUEUE_DISCIPLINE_PRIORITY : THREAD_QUEUE_DISCIPLINE_FIFO,
    STATES_WAITING_FOR_MESSAGE,
    CORE_MESSAGE_QUEUE_STATUS_TIMEOUT
  );

  return true;
}
Exemplo n.º 2
0
bool _CORE_message_queue_Initialize(
  CORE_message_queue_Control    *the_message_queue,
  CORE_message_queue_Attributes *the_message_queue_attributes,
  uint32_t                       maximum_pending_messages,
  size_t                         maximum_message_size
)
{
  size_t message_buffering_required;
  size_t allocated_message_size;

  the_message_queue->maximum_pending_messages   = maximum_pending_messages;
  the_message_queue->number_of_pending_messages = 0;
  the_message_queue->maximum_message_size       = maximum_message_size;
  _CORE_message_queue_Set_notify( the_message_queue, NULL, NULL );

  /*
   *  Round size up to multiple of a pointer for chain init and
   *  check for overflow on adding overhead to each message.
   */
  allocated_message_size = maximum_message_size;
  if (allocated_message_size & (sizeof(uint32_t) - 1)) {
    allocated_message_size += sizeof(uint32_t);
    allocated_message_size &= ~(sizeof(uint32_t) - 1);
  }

  if (allocated_message_size < maximum_message_size)
    return false;

  /*
   *  Calculate how much total memory is required for message buffering and
   *  check for overflow on the multiplication.
   */
  message_buffering_required = (size_t) maximum_pending_messages *
       (allocated_message_size + sizeof(CORE_message_queue_Buffer_control));

  if (message_buffering_required < allocated_message_size)
    return false;

  /*
   *  Attempt to allocate the message memory
   */
  the_message_queue->message_buffers = (CORE_message_queue_Buffer *)
     _Workspace_Allocate( message_buffering_required );

  if (the_message_queue->message_buffers == 0)
    return false;

  /*
   *  Initialize the pool of inactive messages, pending messages,
   *  and set of waiting threads.
   */
  _Chain_Initialize (
    &the_message_queue->Inactive_messages,
    the_message_queue->message_buffers,
    (size_t) maximum_pending_messages,
    allocated_message_size + sizeof( CORE_message_queue_Buffer_control )
  );

  _Chain_Initialize_empty( &the_message_queue->Pending_messages );

  _Thread_queue_Initialize(
    &the_message_queue->Wait_queue,
    _CORE_message_queue_Is_priority( the_message_queue_attributes ) ?
       THREAD_QUEUE_DISCIPLINE_PRIORITY : THREAD_QUEUE_DISCIPLINE_FIFO,
    STATES_WAITING_FOR_MESSAGE,
    CORE_MESSAGE_QUEUE_STATUS_TIMEOUT
  );

  return true;
}