a binary heap event scheduler More...

#include "heap-scheduler.h"

Inheritance diagram for ns3::HeapScheduler:

Collaboration diagram for ns3::HeapScheduler:

Public Member Functions
	HeapScheduler ()
	Constructor.

	~HeapScheduler () override
	Destructor.

void	Insert (const Scheduler::Event &ev) override
	Insert a new Event in the schedule.

bool	IsEmpty () const override
	Test if the schedule is empty.

Scheduler::Event	PeekNext () const override
	Get a pointer to the next event.

void	Remove (const Scheduler::Event &ev) override
	Remove a specific event from the event list.

Scheduler::Event	RemoveNext () override
	Remove the earliest event from the event list.

Public Member Functions inherited from ns3::Scheduler
	~Scheduler () override=0
	Destructor.

Public Member Functions inherited from ns3::Object
	Object ()
	Constructor.

	~Object () override
	Destructor.

void	AggregateObject (Ptr< Object > other)
	Aggregate two Objects together.

void	Dispose ()
	Dispose of this Object.

AggregateIterator	GetAggregateIterator () const
	Get an iterator to the Objects aggregated to this one.

TypeId	GetInstanceTypeId () const override
	Get the most derived TypeId for this Object.

template<typename T >
Ptr< T >	GetObject () const
	Get a pointer to the requested aggregated Object.

template<>
Ptr< Object >	GetObject () const
	Specialization of () for objects of type ns3::Object.

template<typename T >
Ptr< T >	GetObject (TypeId tid) const
	Get a pointer to the requested aggregated Object by TypeId.

template<>
Ptr< Object >	GetObject (TypeId tid) const
	Specialization of (TypeId tid) for objects of type ns3::Object.

void	Initialize ()
	Invoke DoInitialize on all Objects aggregated to this one.

bool	IsInitialized () const
	Check if the object has been initialized.

void	UnidirectionalAggregateObject (Ptr< Object > other)
	Aggregate an Object to another Object.

Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter >
	SimpleRefCount ()
	Default constructor.

	SimpleRefCount (const SimpleRefCount &o)
	Copy constructor.

uint32_t	GetReferenceCount () const
	Get the reference count of the object.

SimpleRefCount &	operator= (const SimpleRefCount &o)
	Assignment operator.

void	Ref () const
	Increment the reference count.

void	Unref () const
	Decrement the reference count.

Public Member Functions inherited from ns3::ObjectBase
virtual	~ObjectBase ()
	Virtual destructor.

void	GetAttribute (std::string name, AttributeValue &value, bool permissive=false) const
	Get the value of an attribute, raising fatal errors if unsuccessful.

bool	GetAttributeFailSafe (std::string name, AttributeValue &value) const
	Get the value of an attribute without raising errors.

void	SetAttribute (std::string name, const AttributeValue &value)
	Set a single attribute, raising fatal errors if unsuccessful.

bool	SetAttributeFailSafe (std::string name, const AttributeValue &value)
	Set a single attribute without raising errors.

bool	TraceConnect (std::string name, std::string context, const CallbackBase &cb)
	Connect a TraceSource to a Callback with a context.

bool	TraceConnectWithoutContext (std::string name, const CallbackBase &cb)
	Connect a TraceSource to a Callback without a context.

bool	TraceDisconnect (std::string name, std::string context, const CallbackBase &cb)
	Disconnect from a TraceSource a Callback previously connected with a context.

bool	TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb)
	Disconnect from a TraceSource a Callback previously connected without a context.

Static Public Member Functions
static TypeId	GetTypeId ()
	Register this type.

Static Public Member Functions inherited from ns3::Scheduler
static TypeId	GetTypeId ()
	Register this type.

Static Public Member Functions inherited from ns3::Object
static TypeId	GetTypeId ()
	Register this type.

Static Public Member Functions inherited from ns3::ObjectBase
static TypeId	GetTypeId ()
	Get the type ID.

Private Types
typedef std::vector< Scheduler::Event >	BinaryHeap
	Event list type: vector of Events, managed as a heap.

Private Member Functions
void	BottomUp ()
	Percolate a newly inserted Last item to its proper position.

void	Exch (std::size_t a, std::size_t b)
	Swap two items.

bool	IsBottom (std::size_t id) const
	Test if an index is at the bottom of the heap.

bool	IsLessStrictly (std::size_t a, std::size_t b) const
	Compare (less than) two items.

bool	IsRoot (std::size_t id) const
	Test if an index is the root.

std::size_t	Last () const
	Return the index of the last element.

std::size_t	LeftChild (std::size_t id) const
	Get the left child of a given entry.

std::size_t	Parent (std::size_t id) const
	Get the parent index of a given entry.

std::size_t	RightChild (std::size_t id) const
	Get the right child index of a given entry.

std::size_t	Root () const
	Get the root index of the heap.

std::size_t	Sibling (std::size_t id) const
	Get the next sibling of a given entry.

std::size_t	Smallest (std::size_t a, std::size_t b) const
	Minimum of two items.

void	TopDown (std::size_t start)
	Percolate a deletion bubble down the heap.

Private Attributes
BinaryHeap	m_heap
	The event list.

Additional Inherited Members
Protected Member Functions inherited from ns3::Object
	Object (const Object &o)
	Copy an Object.

virtual void	DoDispose ()
	Destructor implementation.

virtual void	DoInitialize ()
	Initialize() implementation.

virtual void	NotifyNewAggregate ()
	Notify all Objects aggregated to this one of a new Object being aggregated.

Protected Member Functions inherited from ns3::ObjectBase
void	ConstructSelf (const AttributeConstructionList &attributes)
	Complete construction of ObjectBase; invoked by derived classes.

virtual void	NotifyConstructionCompleted ()
	Notifier called once the ObjectBase is fully constructed.

Related Symbols inherited from ns3::ObjectBase
static TypeId	GetObjectIid ()
	Ensure the TypeId for ObjectBase gets fully configured to anchor the inheritance tree properly.

Detailed Description

a binary heap event scheduler

This code started as a c++ translation of a Java-based code written in 2005 to implement a heap sort. So, this binary heap is really a pretty straightforward implementation of the classic data structure, implemented on a std::vector. This implementation does not make use of any of the heap functions from the STL. Not much to say about it.

What is smart about this code ?

it does not use the index 0 in the array to avoid having to convert C-style array indexes (which start at zero) and heap-style indexes (which start at 1). This is why all indexes start at 1, and that the index of the root is 1.
It uses a slightly non-standard while loop for top-down heapify to move one if statement out of the loop.

Time Complexity

Operation	Amortized Time	Reason
Insert()	Logarithmic	Heapify
IsEmpty()	Constant	Explicit queue size
PeekNext()	Constant	Heap kept sorted
Remove()	Logarithmic	Search, heapify
RemoveNext()	Logarithmic	Heapify

Memory Complexity

Category	Memory	Reason
Overhead	3 x `sizeof (*)` (24 bytes)	`std::vector`
Per Event	0	Events stored in `std::vector` directly

Definition at line 62 of file heap-scheduler.h.

Member Typedef Documentation

◆ BinaryHeap

typedef std::vector<Scheduler::Event> ns3::HeapScheduler::BinaryHeap

private

Event list type: vector of Events, managed as a heap.

Definition at line 85 of file heap-scheduler.h.

Constructor & Destructor Documentation

◆ HeapScheduler()

ns3::HeapScheduler::HeapScheduler ( )

Constructor.

Definition at line 40 of file heap-scheduler.cc.

References m_heap, and NS_LOG_FUNCTION.

◆ ~HeapScheduler()

ns3::HeapScheduler::~HeapScheduler ( )

override

Destructor.

Definition at line 50 of file heap-scheduler.cc.

References NS_LOG_FUNCTION.

Member Function Documentation

◆ BottomUp()

void ns3::HeapScheduler::BottomUp ( )

private

Percolate a newly inserted Last item to its proper position.

Definition at line 144 of file heap-scheduler.cc.

References Exch(), IsLessStrictly(), IsRoot(), Last(), NS_LOG_FUNCTION, and Parent().

Referenced by Insert().

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◆ Exch()

void ns3::HeapScheduler::Exch	(	std::size_t	a,
		std::size_t	b )

inlineprivate

Swap two items.

Parameters

[in]	a	The first item.
[in]	b	The second item.

Definition at line 112 of file heap-scheduler.cc.

References m_heap, NS_ASSERT, NS_LOG_DEBUG, and NS_LOG_FUNCTION.

Referenced by BottomUp(), Remove(), RemoveNext(), and TopDown().

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◆ GetTypeId()

TypeId ns3::HeapScheduler::GetTypeId ( )

static

Register this type.

Returns: The object TypeId.

Definition at line 31 of file heap-scheduler.cc.

References ns3::TypeId::SetParent().

Referenced by SimulatorTestSuite::SimulatorTestSuite().

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◆ Insert()

void ns3::HeapScheduler::Insert ( const Scheduler::Event & ev )

overridevirtual

Insert a new Event in the schedule.

Parameters

[in] ev Event to store in the event list

Implements ns3::Scheduler.

Definition at line 191 of file heap-scheduler.cc.

References BottomUp(), m_heap, and NS_LOG_FUNCTION.

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◆ IsBottom()

bool ns3::HeapScheduler::IsBottom ( std::size_t id ) const

inlineprivate

Test if an index is at the bottom of the heap.

Parameters

[in] id The index to test.

Returns: true if the index is at the bottom.

Definition at line 105 of file heap-scheduler.cc.

References m_heap, and NS_LOG_FUNCTION.

Referenced by TopDown().

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◆ IsEmpty()

bool ns3::HeapScheduler::IsEmpty ( ) const

overridevirtual

Test if the schedule is empty.

Returns: true if the event list is empty and false otherwise.

Implements ns3::Scheduler.

Definition at line 137 of file heap-scheduler.cc.

References m_heap, and NS_LOG_FUNCTION.

◆ IsLessStrictly()

bool ns3::HeapScheduler::IsLessStrictly	(	std::size_t	a,
		std::size_t	b ) const

inlineprivate

Compare (less than) two items.

Parameters

[in]	a	The first item.
[in]	b	The second item.

Returns: true if a < b

Definition at line 123 of file heap-scheduler.cc.

References m_heap, and NS_LOG_FUNCTION.

Referenced by BottomUp(), Smallest(), and TopDown().

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◆ IsRoot()

bool ns3::HeapScheduler::IsRoot ( std::size_t id ) const

inlineprivate

Test if an index is the root.

Parameters

[in] id The index to test.

Returns: true if the id is the root.

Definition at line 91 of file heap-scheduler.cc.

References NS_LOG_FUNCTION, and Root().

Referenced by BottomUp().

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◆ Last()

std::size_t ns3::HeapScheduler::Last ( ) const

private

Return the index of the last element.

Returns: The last index.

Definition at line 98 of file heap-scheduler.cc.

References m_heap, and NS_LOG_FUNCTION.

Referenced by BottomUp(), Remove(), and RemoveNext().

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◆ LeftChild()

std::size_t ns3::HeapScheduler::LeftChild ( std::size_t id ) const

inlineprivate

Get the left child of a given entry.

Parameters

[in] id The parent index.

Returns: The index of the left (first) child.

Definition at line 70 of file heap-scheduler.cc.

References NS_LOG_FUNCTION.

Referenced by TopDown().

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◆ Parent()

std::size_t ns3::HeapScheduler::Parent ( std::size_t id ) const

inlineprivate

Get the parent index of a given entry.

Parameters

[in] id The child index.

Returns: The index of the parent of id .

Definition at line 56 of file heap-scheduler.cc.

References NS_LOG_FUNCTION.

Referenced by BottomUp().

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◆ PeekNext()

Scheduler::Event ns3::HeapScheduler::PeekNext ( ) const

overridevirtual

Get a pointer to the next event.

This method cannot be invoked if the list is empty.

Returns: A pointer to the next earliest event. The caller takes ownership of the returned pointer.

Implements ns3::Scheduler.

Definition at line 199 of file heap-scheduler.cc.

References m_heap, NS_LOG_FUNCTION, and Root().

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◆ Remove()

void ns3::HeapScheduler::Remove ( const Scheduler::Event & ev )

overridevirtual

Remove a specific event from the event list.

This method cannot be invoked if the list is empty.

Parameters

[in] ev The event to remove

Implements ns3::Scheduler.

Definition at line 217 of file heap-scheduler.cc.

References Exch(), ns3::Scheduler::Event::impl, ns3::Scheduler::Event::key, Last(), m_heap, ns3::Scheduler::EventKey::m_uid, NS_ASSERT, NS_LOG_FUNCTION, and TopDown().

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◆ RemoveNext()

Scheduler::Event ns3::HeapScheduler::RemoveNext ( )

overridevirtual

Remove the earliest event from the event list.

This method cannot be invoked if the list is empty.

Returns: The Event.

Implements ns3::Scheduler.

Definition at line 206 of file heap-scheduler.cc.

References Exch(), Last(), m_heap, NS_LOG_FUNCTION, Root(), and TopDown().

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◆ RightChild()

std::size_t ns3::HeapScheduler::RightChild ( std::size_t id ) const

inlineprivate

Get the right child index of a given entry.

Parameters

[in] id The parent index.

Returns: The index of the right (second) child.

Definition at line 77 of file heap-scheduler.cc.

References NS_LOG_FUNCTION.

Referenced by TopDown().

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◆ Root()

std::size_t ns3::HeapScheduler::Root ( ) const

inlineprivate

Get the root index of the heap.

Returns: The root index.

Definition at line 84 of file heap-scheduler.cc.

References NS_LOG_FUNCTION.

Referenced by IsRoot(), PeekNext(), and RemoveNext().

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◆ Sibling()

std::size_t ns3::HeapScheduler::Sibling ( std::size_t id ) const

private

Get the next sibling of a given entry.

Parameters

[in] id The starting index.

Returns: The next sibling of id .

Definition at line 63 of file heap-scheduler.cc.

References NS_LOG_FUNCTION.

◆ Smallest()

std::size_t ns3::HeapScheduler::Smallest	(	std::size_t	a,
		std::size_t	b ) const

inlineprivate

Minimum of two items.

Parameters

[in]	a	The first item.
[in]	b	The second item.

Returns: The smaller of the two items.

Definition at line 130 of file heap-scheduler.cc.

References IsLessStrictly(), and NS_LOG_FUNCTION.

Referenced by TopDown().

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◆ TopDown()

void ns3::HeapScheduler::TopDown ( std::size_t start )

private

Percolate a deletion bubble down the heap.

Parameters

[in] start Starting entry.

Definition at line 156 of file heap-scheduler.cc.

References Exch(), IsBottom(), IsLessStrictly(), LeftChild(), NS_ASSERT, NS_LOG_FUNCTION, RightChild(), and Smallest().

Referenced by Remove(), and RemoveNext().

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Member Data Documentation

◆ m_heap

BinaryHeap ns3::HeapScheduler::m_heap

private

The event list.

Definition at line 173 of file heap-scheduler.h.

Referenced by HeapScheduler(), Exch(), Insert(), IsBottom(), IsEmpty(), IsLessStrictly(), Last(), PeekNext(), Remove(), and RemoveNext().

The documentation for this class was generated from the following files:

src/core/model/heap-scheduler.h
src/core/model/heap-scheduler.cc

Public Member Functions

Static Public Member Functions

Private Types

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ BinaryHeap

Constructor & Destructor Documentation

◆ HeapScheduler()

◆ ~HeapScheduler()

Member Function Documentation

◆ BottomUp()

◆ Exch()

◆ GetTypeId()

◆ Insert()

◆ IsBottom()

◆ IsEmpty()

◆ IsLessStrictly()

◆ IsRoot()

◆ Last()

◆ LeftChild()

◆ Parent()

◆ PeekNext()

◆ Remove()

◆ RemoveNext()

◆ RightChild()

◆ Root()

◆ Sibling()

◆ Smallest()

◆ TopDown()

Member Data Documentation

◆ m_heap