osdMessageQueue.c File Reference

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <rtems.h>
#include <rtems/error.h>
#include "epicsMessageQueue.h"
#include "errlog.h"

Include dependency graph for osdMessageQueue.c:

Go to the source code of this file.

Macros
#define	__RTEMS_VIOLATE_KERNEL_VISIBILITY__   1

Functions
LIBCOM_API epicsMessageQueueId epicsStdCall	epicsMessageQueueCreate (unsigned int capacity, unsigned int maximumMessageSize)
	Create a message queue. More...
LIBCOM_API int epicsStdCall	epicsMessageQueueSend (epicsMessageQueueId id, void *message, unsigned int messageSize)
	Send a message. More...
LIBCOM_API int epicsStdCall	epicsMessageQueueSendWithTimeout (epicsMessageQueueId id, void *message, unsigned int messageSize, double timeout)
	Send a message or timeout. More...
LIBCOM_API int epicsStdCall	epicsMessageQueueTryReceive (epicsMessageQueueId id, void *message, unsigned int size)
	Try to receive a message. More...
LIBCOM_API int epicsStdCall	epicsMessageQueueReceive (epicsMessageQueueId id, void *message, unsigned int size)
	Fetch the next message on the queue. More...
LIBCOM_API int epicsStdCall	epicsMessageQueueReceiveWithTimeout (epicsMessageQueueId id, void *message, unsigned int size, double timeout)
	Wait for a message to be queued. More...
LIBCOM_API int epicsStdCall	epicsMessageQueuePending (epicsMessageQueueId id)
	How many messages are queued. More...
LIBCOM_API void epicsStdCall	epicsMessageQueueShow (epicsMessageQueueId id, int level)
	Displays some information about the message queue. More...

Macro Definition Documentation

#define __RTEMS_VIOLATE_KERNEL_VISIBILITY__   1

Definition at line 20 of file osdMessageQueue.c.

Function Documentation

LIBCOM_API epicsMessageQueueId epicsStdCall epicsMessageQueueCreate	(	unsigned int	capacity,
		unsigned int	maximumMessageSize
	)

Create a message queue.

Parameters

capacity	Maximum number of messages to queue
maximumMessageSize	Number of bytes of the largest message that may be queued

Returns

An identifier for the new queue, or 0.

Definition at line 32 of file osdMessageQueue.c.

{
    rtems_status_code sc;
    epicsMessageQueueId id = calloc(1, sizeof(*id));
    rtems_interrupt_level level;
    static char c1 = 'a';
    static char c2 = 'a';
    static char c3 = 'a';

    if(!id)
        return NULL;

    sc = rtems_message_queue_create (rtems_build_name ('Q', c3, c2, c1),
        capacity,
        maximumMessageSize,
        RTEMS_FIFO|RTEMS_LOCAL,
        &id->id);
    if (sc != RTEMS_SUCCESSFUL) {
        free(id);
        errlogPrintf ("Can't create message queue: %s\n", rtems_status_text (sc));
        return NULL;
    }
    id->maxSize = maximumMessageSize;
    id->localBuf = NULL;
    rtems_interrupt_disable (level);
    if (c1 == 'z') {
        if (c2 == 'z') {
            if (c3 == 'z') {
                c3 = 'a';
            }
            else {
                c3++;
            }
            c2 = 'a';
        }
        else {
            c2++;
        }
        c1 = 'a';
    }
    else {
        c1++;
    }
    rtems_interrupt_enable (level);
    return id;
}

LIBCOM_API int epicsStdCall epicsMessageQueuePending

(

epicsMessageQueueId

id

)

How many messages are queued.

Parameters

id	Message queue identifier.

Returns

The number of messages presently in the queue.

Definition at line 227 of file osdMessageQueue.c.

{
    uint32_t count;
    rtems_status_code sc;

    sc = rtems_message_queue_get_number_pending(id->id, &count);
    if (sc != RTEMS_SUCCESSFUL) {
        errlogPrintf("Message queue %x get number pending failed: %s\n",
                                                        (unsigned int)id,
                                                        rtems_status_text(sc));
        return -1;
    }
    return count;
}

LIBCOM_API int epicsStdCall epicsMessageQueueReceive	(	epicsMessageQueueId	id,
		void *	message,
		unsigned int	size
	)

Fetch the next message on the queue.

Wait for a message to be sent if the queue is empty, then move the first message queued to the specified location.

If the received message is larger than the specified message size the implementation may either return -1, or truncate the message. It is most efficient if the messageBufferSize is equal to the maximumMessageSize with which the message queue was created.

Returns

Number of bytes in the message.

-1 if the buffer is too small for the message.

Definition at line 193 of file osdMessageQueue.c.

{
    return receiveMessage(id, message, size, RTEMS_WAIT, RTEMS_NO_TIMEOUT);
}

LIBCOM_API int epicsStdCall epicsMessageQueueReceiveWithTimeout	(	epicsMessageQueueId	id,
		void *	message,
		unsigned int	size,
		double	timeout
	)

Wait for a message to be queued.

Wait up to timeout seconds for a message to be sent if the queue is empty, then move the first message to the specified location.

If the received message is larger than the specified message buffer size the implementation may either return -1, or truncate the message. It is most efficient if the messageBufferSize is equal to the maximumMessageSize with which the message queue was created.

Returns

Number of bytes in the message.

-1 if a message is not received within the timeout interval.

Definition at line 201 of file osdMessageQueue.c.

{
    rtems_interval delay;
    uint32_t wait;
    extern double rtemsTicksPerSecond_double;

    /*
     * Convert time to ticks
     */
    if (timeout <= 0.0) {
        wait = RTEMS_NO_WAIT;
        delay = 0;
    }
    else {
        wait = RTEMS_WAIT;
        delay = (int)(timeout * rtemsTicksPerSecond_double);
        if (delay == 0)
            delay++;
    }
    return receiveMessage(id, message, size, wait, delay);
}

LIBCOM_API int epicsStdCall epicsMessageQueueSend	(	epicsMessageQueueId	id,
		void *	message,
		unsigned int	messageSize
	)

Send a message.

Returns

0 if the message was sent to a receiver or queued for future delivery.

-1 if the message is larger than the queue's maximum message size.

Definition at line 122 of file osdMessageQueue.c.

{
    if (rtems_message_queue_send_timeout(id->id, message, messageSize, RTEMS_NO_TIMEOUT) == RTEMS_SUCCESSFUL)
        return 0;
    else
        return -1;
}

LIBCOM_API int epicsStdCall epicsMessageQueueSendWithTimeout	(	epicsMessageQueueId	id,
		void *	message,
		unsigned int	messageSize,
		double	timeout
	)

Send a message or timeout.

Returns

0 if the message was sent to a receiver or queued for future delivery.

-1 if the timeout was reached before the message could be sent or queued, or if the message is larger than the queue's maximum message size.

Definition at line 133 of file osdMessageQueue.c.

{
    rtems_interval delay;
    extern double rtemsTicksPerSecond_double;

    /*
     * Convert time to ticks
     */
    if (timeout <= 0.0)
        return epicsMessageQueueTrySend(id, message, messageSize);
    delay = (int)(timeout * rtemsTicksPerSecond_double);
    if (delay == 0)
        delay++;
    if (rtems_message_queue_send_timeout(id->id, message, messageSize, delay) == RTEMS_SUCCESSFUL)
        return 0;
    else
        return -1;
}

LIBCOM_API void epicsStdCall epicsMessageQueueShow	(	epicsMessageQueueId	id,
		int	level
	)

Displays some information about the message queue.

Parameters

id	Message queue identifier.
level	Controls the amount of information displayed.

Definition at line 243 of file osdMessageQueue.c.

{
    int pending = epicsMessageQueuePending(id);
    if (pending >= 0)
        printf ("Message queue %lx -- Pending: %d\n", (unsigned long)id, pending);
}

LIBCOM_API int epicsStdCall epicsMessageQueueTryReceive	(	epicsMessageQueueId	id,
		void *	message,
		unsigned int	size
	)

Try to receive a message.

If the queue holds at least one message, the first message on the queue is moved to the specified location and the length of that message is returned.

If the received message is larger than the specified message size the implementation may either return -1, or truncate the message. It is most efficient if the messageBufferSize is equal to the maximumMessageSize with which the message queue was created.

Returns

Number of bytes in the message.

-1 if the message queue is empty, or the buffer too small.

Definition at line 185 of file osdMessageQueue.c.

{
    return receiveMessage(id, message, size, RTEMS_NO_WAIT, 0);
}