DDS::Sequence< T > Class Template Reference
[Sequence Support]

<<interface>> <<generic>> A type-safe, ordered collection of elements. The type of these elements is referred to in this documentation as Foo. More...

#include <managed_sequence.h>

Inheritance diagram for DDS::Sequence< T >:

DDS::ChannelSettingsSeq DDS::ConditionSeq DDS::DataReaderSeq DDS::EnumMemberSeq DDS::InstanceHandleSeq DDS::LocatorFilterSeq DDS::LocatorSeq DDS::LongDoubleSeq DDS::PropertySeq DDS::PublisherSeq DDS::QosPolicyCountSeq DDS::StructMemberSeq DDS::SubscriberSeq DDS::TransportMulticastSettingsSeq DDS::TransportUnicastSettingsSeq DDS::UnionMemberSeq DDS::ValueMemberSeq DDS::WstringSeq

List of all members.

Public Member Functions

System::Boolean ensure_length (System::Int32 length, System::Int32 max)
 Set the sequence to the desired length, and resize the sequence if necessary.
virtual T get_at (System::Int32 i)
 Get the i-th element for a const sequence.
virtual void set_at (System::Int32 i, T val)
 Set the i-th element of the sequence.
void loan (array< T >^buffer, System::Int32 new_length)
 Loan a contiguous buffer to this sequence.
virtual void unloan ()
 Return the loaned buffer in the sequence and set the maximum to 0.
void from_array (array< T >^arr)
 Copy elements from an array of elements, resizing the sequence if necessary. The original contents of the sequence (if any) are replaced.
void to_array (array< T >^arr)
 Copy elements to an array of elements. The original contents of the array (if any) are replaced.
System::Boolean copy_from (Sequence< T >^src_seq)
 Copy elements from another sequence, resizing the sequence if necessary.
virtual System::Boolean copy_from_no_alloc (Sequence< T >^src_seq)
 Copy elements from another sequence, only if the destination sequence has enough capacity.

Properties

System::Int32 length [get, set]
 The logical length of this sequence.
virtual System::Int32 maximum [get, set]
 The current maximum number of elements that can be stored in this sequence.
array< T >^ buffer [get]
 Return the contiguous buffer of the sequence.
System::Boolean has_ownership [get]
 Return the value of the owned flag.

Detailed Description

template<typename T>
class DDS::Sequence< T >

<<interface>> <<generic>> A type-safe, ordered collection of elements. The type of these elements is referred to in this documentation as Foo.

For users who define data types in OMG IDL, this type corresponds to the IDL express sequence<Foo>.

For any user-data type Foo that an application defines for the purpose of data-distribution with RTI Data Distribution Service, a FooSeq is generated. We refer to an IDL sequence<Foo> as FooSeq.

The state of a sequence is described by the properties 'maximum', 'length' and 'owned'.

See also:
DDS::TypedDataWriter, DDS::TypedDataReader, FooTypeSupport, rtiddsgen

Member Function Documentation

template<typename T>
System::Boolean DDS::Sequence< T >::ensure_length ( System::Int32  length,
System::Int32  max 
)

Set the sequence to the desired length, and resize the sequence if necessary.

If the current maximum is greater than the desired length, then sequence is not resized.

Otherwise if this sequence owns its buffer, the sequence is resized to the new maximum by freeing and re-allocating the buffer. However, if the sequence does not own its buffer, this operation will fail.

This function allows user to avoid unnecessary buffer re-allocation.

Precondition:
length <= max

owned == true if sequence needs to be resized

Postcondition:
length == length

maximum == max if resized

Parameters:
length <<in>> The new length that should be set. Must be >= 0.
max <<in>> If sequence need to be resized, this is the maximum that should be set. max >= length
Returns:
true on success, false if the preconditions are not met. In that case the sequence is not modified.

template<typename T>
virtual T DDS::Sequence< T >::get_at ( System::Int32  i  )  [virtual]

Get the i-th element for a const sequence.

Parameters:
i index of element to access, must be >= 0 and less than DDS::Sequence::length
Returns:
the i-th element

Reimplemented in DDS::LoanableSequence< E >, DDS::LoanableSequence< M^ >, DDS::LoanableSequence< DDS::SampleInfo^ >, DDS::LoanableSequence< DDS::TopicBuiltinTopicData^ >, DDS::LoanableSequence< DDS::PublicationBuiltinTopicData^ >, DDS::LoanableSequence< Foo^ >, DDS::LoanableSequence< DDS::ParticipantBuiltinTopicData^ >, and DDS::LoanableSequence< DDS::SubscriptionBuiltinTopicData^ >.

template<typename T>
virtual void DDS::Sequence< T >::set_at ( System::Int32  i,
T  val 
) [virtual]

Set the i-th element of the sequence.

Parameters:
i index of element to access, must be >= 0 and less than DDS::Sequence::length
val <<in>> value to be set

template<typename T>
void DDS::Sequence< T >::loan ( array< T >^  buffer,
System::Int32  new_length 
)

Loan a contiguous buffer to this sequence.

This operation changes the owned flag of the sequence to false and also sets the underlying buffer used by the sequence. See the user's manual for more information about sequences and memory ownership.

Use this method if you want to manage the memory used by the sequence yourself. You must provide an array of elements and integers indicating how many elements are allocated in that array (i.e. the maximum) and how many elements are valid (i.e. the length). The sequence will subsequently use the memory you provide and will not permit it to be freed by a call to DDS::Sequence::maximum.

By default, a sequence you create owns its memory unless you explicitly loan memory of your own to it. In a very few cases, RTI Data Distribution Service will return a sequence to you that has a loan; those cases are documented as such. For example, if you call DDS::TypedDataReader::read or DDS::TypedDataReader::take and pass in sequences with no loan and no memory allocated, RTI Data Distribution Service will loan memory to your sequences which must be unloaned with DDS::TypedDataReader::return_loan. See the documentation of those methods for more information.

Precondition:
DDS::Sequence::maximum == 0; i.e. the sequence has no memory allocated to it.

DDS::Sequence::has_ownership == true; i.e. the sequence does not already have an outstanding loan

Postcondition:
The sequence will store its elements in the buffer provided.

DDS::Sequence::has_ownership == false

DDS::Sequence::length == new_length

DDS::Sequence::maximum == new_max

Parameters:
buffer The new buffer that the sequence will use. Must point to enough memory to hold new_max elements of type Foo. It may be NULL if new_max == 0.
new_length The desired new length for the sequence.
Returns:
true if buffer is successfully loaned to this sequence or false otherwise. Failure only occurs due to failing to meet the pre-conditions. Upon failure the sequence remains unmodified.
See also:
DDS::Sequence::unloan, DDS::Sequence::loan_discontiguous

template<typename T>
virtual void DDS::Sequence< T >::unloan (  )  [virtual]

Return the loaned buffer in the sequence and set the maximum to 0.

This method affects only the state of this sequence; it does not change the contents of the buffer in any way.

Only the user who originally loaned a buffer should return that loan, as the user may have dependencies on that memory known only to them. Unloaning someone else's buffer may cause unspecified problems. For example, suppose a sequence is loaning memory from a custom memory pool. A user of the sequence likely has no way to release the memory back into the pool, so unloaning the sequence buffer would result in a resource leak. If the user were to then re-loan a different buffer, the original creator of the sequence would have no way to discover, when freeing the sequence, that the loan no longer referred to its own memory and would thus not free the user's memory properly, exacerbating the situation and leading to undefined behavior.

Precondition:
owned == false
Postcondition:
owned == true

maximum == 0

Returns:
true if the preconditions were met. Otherwise false. The function only fails if the pre-conditions are not met, in which case it leaves the sequence unmodified.
See also:
DDS::Sequence<T>::loan(array<T>^, System::Int32), DDS::Sequence::loan_discontiguous, DDS::Sequence::maximum

Reimplemented in DDS::LoanableSequence< E >, DDS::LoanableSequence< M^ >, DDS::LoanableSequence< DDS::SampleInfo^ >, DDS::LoanableSequence< DDS::TopicBuiltinTopicData^ >, DDS::LoanableSequence< DDS::PublicationBuiltinTopicData^ >, DDS::LoanableSequence< Foo^ >, DDS::LoanableSequence< DDS::ParticipantBuiltinTopicData^ >, and DDS::LoanableSequence< DDS::SubscriptionBuiltinTopicData^ >.

template<typename T>
void DDS::Sequence< T >::from_array ( array< T >^  arr  ) 

Copy elements from an array of elements, resizing the sequence if necessary. The original contents of the sequence (if any) are replaced.

Fill the elements in this sequence by copying the corresponding elements in array. The original contents in this sequence are replaced via the element assignment operation (Foo_copy() function). By default, elements are discarded; 'delete' is not invoked on the discarded elements.

Precondition:
this::owned == true
Postcondition:
this::length == length

this[i] == array[i] for 0 <= i < length

this::owned == true

Parameters:
arr <<in>> The array of elements to be copy elements from
Returns:
true if the array was successfully copied; false otherwise.
Note:
If the pre-conditions are not met, the method will print a message to stdout and leave this sequence unchanged.

template<typename T>
void DDS::Sequence< T >::to_array ( array< T >^  arr  ) 

Copy elements to an array of elements. The original contents of the array (if any) are replaced.

Copy the elements of this sequence to the corresponding elements in the array. The original contents of the array are replaced via the element assignment operation (Foo_copy() function). By default, elements are discarded; 'delete' is not invoked on the discarded elements.

Parameters:
arr <<in>> The array of elements to be filled with elements from this sequence
Returns:
true if the elements of the sequence were successfully copied; false otherwise.

template<typename T>
System::Boolean DDS::Sequence< T >::copy_from ( Sequence< T >^  src_seq  ) 

Copy elements from another sequence, resizing the sequence if necessary.

This method invokes DDS::Sequence::copy_from(DDS::Sequence<T>^) after ensuring that the sequence has enough capacity to hold the elements to be copied.

Parameters:
src_seq <<in>> the sequence from which to copy

See also:
DDS::Sequence::copy_from(DDS::Sequence<T>^)

template<typename T>
virtual System::Boolean DDS::Sequence< T >::copy_from_no_alloc ( Sequence< T >^  src_seq  )  [virtual]

Copy elements from another sequence, only if the destination sequence has enough capacity.

Fill the elements in this sequence by copying the corresponding elements in src_seq. The original contents in this sequence are replaced via the element assignment operation (Foo_copy() function). By default, elements are discarded; 'delete' is not invoked on the discarded elements.

Precondition:
this::maximum >= src_seq::length

this::owned == true

Postcondition:
this::length == src_seq::length

this[i] == src_seq[i] for 0 <= i < target_seq::length

this::owned == true

Parameters:
src_seq <<in>> the sequence from which to copy
Returns:
true if the sequence was successfully copied; false otherwise.
Note:
If the pre-conditions are not met, the operator will print a message to stdout and leave this sequence unchanged.
See also:
DDS::Sequence::copy_from_no_alloc(DDS::Sequence<T>^)

Reimplemented in DDS::LoanableSequence< E >, DDS::LoanableSequence< M^ >, DDS::LoanableSequence< DDS::SampleInfo^ >, DDS::LoanableSequence< DDS::TopicBuiltinTopicData^ >, DDS::LoanableSequence< DDS::PublicationBuiltinTopicData^ >, DDS::LoanableSequence< Foo^ >, DDS::LoanableSequence< DDS::ParticipantBuiltinTopicData^ >, and DDS::LoanableSequence< DDS::SubscriptionBuiltinTopicData^ >.

Property Documentation

template<typename T>
System:: Int32 DDS::Sequence< T >::length [get, set]

The logical length of this sequence.

Getting the property:

Get the length that was last set, or zero if the length has never been set.

Setting the property:

Change the length of this sequence. This method does not allocate/deallocate memory.

The new length must not exceed the maximum of this sequence as returned by the DDS::Sequence::maximum operation. (Note that, if necessary, the maximum of this sequence can be increased manually by using the DDS::Sequence::maximum operation.)

The elements of the sequence are not modified by this operation. If the new length is larger than the original length, the new elements will be uninitialized; if the length is decreased, the old elements that are beyond the new length will physically remain in the sequence but will not be accessible.

Postcondition:
length = new_length.

Parameters:
new_length the new desired length. This value must be non-negative and cannot exceed maximum of the sequence. In other words 0 <= new_length <= maximum

template<typename T>
virtual System:: Int32 DDS::Sequence< T >::maximum [get, set]

The current maximum number of elements that can be stored in this sequence.

Getting the property:

The maximum of the sequence represents the maximum number of elements that the underlying buffer can hold. It does not represent the current number of elements.

The maximum is a non-negative number. It is initialized when the sequence is first created.

maximum can only be changed with the DDS::Sequence::maximum operation.

See also:
DDS::Sequence::length
Setting the property:

Resize this sequence to a new desired maximum. This operation does nothing if the new desired maximum matches the current maximum.

If this sequence owns its buffer and the new maximum is not equal to the old maximum, then the existing buffer will be freed and re-allocated.

Precondition:
owned == true
Postcondition:
owned == true

length == MINIMUM(original length, new_max)

Parameters:
new_max Must be >= 0.

Reimplemented in DDS::LoanableSequence< E >, DDS::LoanableSequence< M^ >, DDS::LoanableSequence< DDS::SampleInfo^ >, DDS::LoanableSequence< DDS::TopicBuiltinTopicData^ >, DDS::LoanableSequence< DDS::PublicationBuiltinTopicData^ >, DDS::LoanableSequence< Foo^ >, DDS::LoanableSequence< DDS::ParticipantBuiltinTopicData^ >, and DDS::LoanableSequence< DDS::SubscriptionBuiltinTopicData^ >.

template<typename T>
array< T>^ DDS::Sequence< T >::buffer [get]

Return the contiguous buffer of the sequence.

Get the underlying buffer where contiguous elements of the sequence are stored. The size of the buffer matches the maximum of the sequence, but only the elements up to the DDS::Sequence::length of the sequence are valid.

This property is real-only.

This method provides almost no encapsulation of the sequence's underlying implementation. Certain operations, such as DDS::Sequence::maximum, may render the buffer invalid. In light of these caveats, this operation should be used with care.

Returns:
buffer that stores contiguous elements in sequence.

template<typename T>
System:: Boolean DDS::Sequence< T >::has_ownership [get]

Return the value of the owned flag.

This property is real-only.

Returns:
true if sequence owns the underlying buffer, or false if it has an outstanding loan.

RTI Data Distribution Service .Net APIs Version 4.5c Copyright © 9 Jun 2010 Real-Time Innovations, Inc