cms_in.cc

Source code for an Numeric Cmputer

	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Check to see if there are any unread messages. */
    if (queuing_header.queue_length == 0) {
	return (status = CMS_READ_OLD);
    }

    /* Read the header for the message. */
    handle_to_global_data->offset += queuing_header.head;
    if (-1 == handle_to_global_data->read(&header, sizeof(CMS_HEADER))) {
	rcs_print_error
	    ("CMS:(%s) Error reading from global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Check the size of the message. */
    if (header.in_buffer_size > max_message_size) {
	rcs_print_error
	    ("CMS:(%s) Message size of %ld exceeds maximum of %ld\n",
	    BufferName, header.in_buffer_size, max_message_size);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Update the message header. */
    header.was_read = 1;
    if (-1 == handle_to_global_data->write(&header, sizeof(CMS_HEADER))) {
	rcs_print_error("CMS:(%s) Error writing to global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Read the message. */
    handle_to_global_data->offset += sizeof(CMS_HEADER);
    if (-1 ==
	handle_to_global_data->read(subdiv_data,
	    (long) header.in_buffer_size)) {
	rcs_print_error
	    ("CMS:(%s) Error reading from global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Update the queuing header for the buffer. */
    queuing_header.head += header.in_buffer_size + sizeof(CMS_HEADER);
    if (queuing_header.head >= queuing_header.end_queue_space) {
	queuing_header.head = sizeof(CMS_QUEUING_HEADER);
    }
    queuing_header.queue_length--;
    if (queuing_header.queue_length == 0) {
	queuing_header.head = queuing_header.tail =
	    sizeof(CMS_QUEUING_HEADER);
	queuing_header.end_queue_space = queuing_header.tail;
    }
    handle_to_global_data->offset = queuing_header_offset;
    if (-1 == handle_to_global_data->write(&queuing_header,
	    sizeof(CMS_QUEUING_HEADER))) {
	rcs_print_error("CMS:(%s) Error writing to global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Check_id so that debug variables for messages missed can be set. */
    check_id(header.write_id);

    return (status);
}

/* It takes several steps to perform a read operation on an neutral buffer.*/
/* 1. Read the encoded  header. */
/* 2. Decode the header. */
/* 3. Check the id and size. */
/* 4. If id and size are ok, then read the message and update the header. */
CMS_STATUS CMS::read_encoded()
{
    /* Produce error message if process does not have permission to read. */
    if (!read_permission_flag) {
	rcs_print_error("CMS: %s was not configured to read %s\n",
	    ProcessName, BufferName);
	return (status = CMS_PERMISSIONS_ERROR);
    }

    /* Check that the handle to the global memory object exists. */
    if (NULL == handle_to_global_data) {
	rcs_print_error("CMS: handle_to_global_data is NULL.\n");
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Read the encoded header for the message. */
    if (-1 == handle_to_global_data->read(encoded_header,
	    encoded_header_size)) {
	rcs_print_error
	    ("CMS:(%s) Error reading from global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Decode the header and store in header structure. */
    decode_header();

    /* Determine if the message in the buffer is new to this process. */
    if (check_id(header.write_id) == CMS_READ_OK) {
	/* Check the size of the message. */
	if (header.in_buffer_size > max_message_size) {
	    rcs_print_error
		("CMS:(%s) Message size of %ld exceeds maximum of %ld\n",
		BufferName, header.in_buffer_size, max_message_size);
	    return (status = CMS_INTERNAL_ACCESS_ERROR);
	}

	/* Read the message. */
	handle_to_global_data->offset += encoded_header_size;
	if (-1 == handle_to_global_data->read(encoded_data,
		(long) header.in_buffer_size)) {
	    rcs_print_error
		("CMS:(%s) Error writing to global memory at %s:%d\n",
		BufferName, __FILE__, __LINE__);
	    return (status = CMS_INTERNAL_ACCESS_ERROR);
	}
	handle_to_global_data->offset -= encoded_header_size;
    }

    /* Update the header. */
    header.was_read = 1;

    encode_header();
    if (-1 ==
	handle_to_global_data->write(encoded_header, encoded_header_size)) {
	rcs_print_error("CMS:(%s) Error writing to global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    return (status);
}

/* It takes several steps to perform a read operation */
 /* when queuing is enabled on a neutral buffer. */
/* 1. Read the encoded queuing_header at the beginning of the buffer. */
/* 2. Decode the queuing_header for the buffer. */
/* 3. Get the head of the queue from the queuing_header. */
/* 4. Read the message header at the head of the queue. */
/* 5. Decode the message header. */
/* 6. Check the id and size. */
/* 7. If id and size are ok, */
 /* then read the message */
CMS_STATUS CMS::queue_read_encoded()
{
    long queuing_header_offset;

    /* Produce error message if process does not have permission to read. */
    if (!read_permission_flag) {
	rcs_print_error("CMS: %s was not configured to read %s\n",
	    ProcessName, BufferName);
	return (status = CMS_PERMISSIONS_ERROR);
    }

    /* Check that the handle to global memory exists. */
    if (NULL == handle_to_global_data) {
	rcs_print_error("CMS: handle_to_global_data is NULL.\n");
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Store the original offset so we can update the queuing header later. */
    queuing_header_offset = handle_to_global_data->offset;

    /* Read the encoded header for the buffer. */
    if (-1 == handle_to_global_data->read(encoded_queuing_header,
	    encoded_queuing_header_size)) {
	rcs_print_error
	    ("CMS:(%s) Error reading from global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Decode the queuing header and store in the queuing_header structrure. */
    decode_queuing_header();

    /* Determine if there are any unread messages. */
    if (queuing_header.queue_length == 0) {
	return (status = CMS_READ_OLD);
    }

    /* Read the header for the message. */
    handle_to_global_data->offset += queuing_header.head;
    if (-1 == handle_to_global_data->read(encoded_header,
	    encoded_header_size)) {
	rcs_print_error
	    ("CMS:(%s) Error reading from global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	rcs_print(" { head=%d,tail=%d,end=%d,length=%d,id=%d }\n",
	    queuing_header.head, queuing_header.tail,
	    queuing_header.end_queue_space, queuing_header.queue_length,
	    queuing_header.write_id);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Decode the message header and store in the header structure. */
    decode_header();

    /* Check the size of the message. */
    if (header.in_buffer_size > max_message_size) {
	rcs_print_error
	    ("CMS:(%s) Message size of %ld exceeds maximum of %ld\n",
	    BufferName, header.in_buffer_size, max_message_size);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Update the message header. */
    header.was_read = 1;
    encode_header();
    if (-1 ==
	handle_to_global_data->write(encoded_header, encoded_header_size)) {
	rcs_print_error("CMS:(%s) Error writing to global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	rcs_print(" { head=%d,tail=%d,end=%d,length=%d,id=%d }\n",
	    queuing_header.head,
	    queuing_header.tail,
	    queuing_header.end_queue_space,
	    queuing_header.queue_length, queuing_header.write_id);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Read the message. */
    handle_to_global_data->offset += encoded_header_size;
    if (-1 ==
	handle_to_global_data->read(encoded_data,
	    (long) header.in_buffer_size)) {
	rcs_print_error
	    ("CMS:(%s) Error reading from global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	rcs_print(" { head=%d,tail=%d,end=%d,length=%d,id=%d }\n",
	    queuing_header.head, queuing_header.tail,
	    queuing_header.end_queue_space, queuing_header.queue_length,
	    queuing_header.write_id);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Update the buffer header. */
    queuing_header.head += header.in_buffer_size + encoded_header_size;
    if (queuing_header.head >= queuing_header.end_queue_space) {
	queuing_header.head = encoded_queuing_header_size;
    }
    queuing_header.queue_length--;
    if (queuing_header.queue_length == 0) {
	queuing_header.head = queuing_header.tail =
	    encoded_queuing_header_size;
	queuing_header.end_queue_space = queuing_header.tail;
    }
    encode_queuing_header();
    handle_to_global_data->offset = queuing_header_offset;
    if (-1 == handle_to_global_data->write(encoded_queuing_header,
	    encoded_queuing_header_size)) {
	rcs_print_error("CMS:(%s) Error writing to global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	rcs_print(" { head=%d,tail=%d,end=%d,length=%d,id=%d }\n",
	    queuing_header.head,
	    queuing_header.tail,
	    queuing_header.end_queue_space,
	    queuing_header.queue_length, queuing_header.write_id);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Check_id so that debug variables for messages missed can be set. */
    check_id(header.write_id);

    return (status);
}

/****************************************************************
* Peek operations are the same as reads,
 except that the header(s) are not updated.
****************************************************************/

/* It takes several steps to perform a peek operation. */
/* 1. Read the header. */
/* 2. Check the id and size. */
/* 3. If id and size are ok, then read the message. */
CMS_STATUS CMS::peek_raw()
{
    /* Produce error message if process does not have permission to read. */
    if (!read_permission_flag) {
	rcs_print_error("CMS: %s was not configured to read %s\n",
	    ProcessName, BufferName);
	return (status = CMS_PERMISSIONS_ERROR);
    }

    /* Check that the handle to global memory exists. */
    if (NULL == handle_to_global_data) {
	rcs_print_error("CMS:(%s) handle_to_global_data is NULL.\n",
	    BufferName);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Read the header for the message. */
    if (-1 == handle_to_global_data->read(&header, sizeof(CMS_HEADER))) {
	rcs_print_error
	    ("CMS:(%s) Error reading from global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Set status to CMS_READ_OLD or CMS_READ_OK */
    if (check_id(header.write_id) == CMS_READ_OLD) {
	return (status);	/* Don't bother copying out an old message. */
    }

    /* Check the size of the message. */
    if (header.in_buffer_size > max_message_size) {
	rcs_print_error
	    ("CMS:(%s) Message size of %ld exceeds maximum of %ld\n",
	    BufferName, header.in_buffer_size, max_message_size);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Read the message. */
    handle_to_global_data->offset += sizeof(CMS_HEADER);
    if (-1 ==
	handle_to_global_data->read(subdiv_data,
	    (long) header.in_buffer_size)) {
	rcs_print_error
	    ("CMS:(%s) Error reading from global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    return (status);
}

/* It takes several steps to perform a peek  operation when queuing is enabled. */
/* 1. Read the queuing_header at the beginning of the buffer. */
/* 2. Get the head of the queue from the queuing_header. */
/* 3. Read the message header at the head of the queue. */
/* 4. Check the id and size. */
/* 5. If id and size are ok, */
 /* then read the message */
CMS_STATUS CMS::queue_peek_raw()
{
    long queuing_header_offset;

    /* Produce error message if process does not have permission to read. */
    if (!read_permission_flag) {
	rcs_print_error("CMS: %s was not configured to read %s\n",
	    ProcessName, BufferName);
	return (status = CMS_PERMISSIONS_ERROR);
    }

    /* Check that the handle to global memory exists. */
    if (NULL == handle_to_global_data) {
	rcs_print_error("CMS: handle_to_global_data is NULL.\n");
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Store the original offset so that we can update the header later. */
    queuing_header_offset = handle_to_global_data->offset;

    /* Read the queuing header for the buffer. */
    if (-1 == handle_to_global_data->read(&queuing_header,
	    sizeof(CMS_QUEUING_HEADER))) {
	rcs_print_error
	    ("CMS:(%s) Error reading from global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Check to see if there are any unread messages. */
    if (queuing_header.queue_length == 0) {
	return (status = CMS_READ_OLD);
    }

    /* Read the header for the message. */
    handle_to_global_data->offset += queuing_header.head;
    if (-1 == handle_to_global_data->read(&header, sizeof(CMS_HEADER))) {
	rcs_print_error
	    ("CMS:(%s) Error reading from global memory at %s:%d\n",
	    BufferName, __FILE__, __LINE__);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }

    /* Check the size of the message. */
    if (header.in_buffer_size > max_message_size) {
	rcs_print_error
	    ("CMS:(%s) Message size of %ld exceeds maximum of %ld\n",
	    BufferName, header.in_buffer_size, max_message_size);
	return (status = CMS_INTERNAL_ACCESS_ERROR);
    }