ns3::Hash::Function::Fnv1a Class Reference

Fnv1a hash function implementation. More...

#include "hash-fnv.h"

Inheritance diagram for ns3::Hash::Function::Fnv1a:

Collaboration diagram for ns3::Hash::Function::Fnv1a:

Public Member Functions
	Fnv1a ()
	Constructor. More...
virtual void	clear (void)
	Restore initial state. More...
uint32_t	GetHash32 (const char *buffer, const size_t size)
	Compute 32-bit hash of a byte buffer. More...
uint64_t	GetHash64 (const char *buffer, const size_t size)
	Compute 64-bit hash of a byte buffer. More...
Public Member Functions inherited from ns3::Hash::Implementation
	Implementation ()
	Constructor. More...
virtual	~Implementation ()
	Destructor. More...
virtual uint32_t	GetHash32 (const char *buffer, const std::size_t size)=0
	Compute 32-bit hash of a byte buffer. More...
virtual uint64_t	GetHash64 (const char *buffer, const std::size_t size)
	Compute 64-bit hash of a byte buffer. More...
Public Member Functions inherited from ns3::SimpleRefCount< Implementation >
	SimpleRefCount ()
	Default constructor. More...
	SimpleRefCount (const SimpleRefCount &o[[maybe_unused]])
	Copy constructor. More...
uint32_t	GetReferenceCount (void) const
	Get the reference count of the object. More...
SimpleRefCount &	operator= ([[maybe_unused]] const SimpleRefCount &o)
	Assignment operator. More...
void	Ref (void) const
	Increment the reference count. More...
void	Unref (void) const
	Decrement the reference count. More...

Private Types
enum	seed { SEED = 0x8BADF00D }
	Seed value. More...

Private Attributes
uint32_t	m_hash32
	Cache last hash value, for incremental hashing. More...
uint64_t	m_hash64
	Cache last hash value, for incremental hashing. More...

Detailed Description

Fnv1a hash function implementation.

This is the venerable Fowler-Noll-Vo hash, version 1A. (See the FNV page.)

The implementation here is taken directly from the published FNV reference code, with minor modifications to wrap into this class. See the hash-fnv.cc file for details.

Definition at line 53 of file hash-fnv.h.

Member Enumeration Documentation

seed

enum ns3::Hash::Function::Fnv1a::seed

private

Seed value.

Enumerator
SEED	Ate bad food.

Definition at line 99 of file hash-fnv.h.

Constructor & Destructor Documentation

Fnv1a()

ns3::Hash::Function::Fnv1a::Fnv1a

(

)

Constructor.

Definition at line 749 of file hash-fnv.cc.

References clear().

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Member Function Documentation

clear()

void ns3::Hash::Function::Fnv1a::clear ( void  )

virtual

Restore initial state.

Implements ns3::Hash::Implementation.

Definition at line 771 of file hash-fnv.cc.

References FNV1_32A_INIT, FNV1A_64_INIT, m_hash32, and m_hash64.

Referenced by Fnv1a().

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GetHash32()

uint32_t ns3::Hash::Function::Fnv1a::GetHash32	(	const char *	buffer,
		const size_t	size
	)

Compute 32-bit hash of a byte buffer.

Call clear () between calls to GetHash32() to reset the internal state and hash each buffer separately.

If you don't call clear() between calls to GetHash32, you can hash successive buffers. The final return value will be the cumulative hash across all calls.

Parameters

[in]	buffer	pointer to the beginning of the buffer
[in]	size	length of the buffer, in bytes

Returns

32-bit hash of the buffer

Definition at line 755 of file hash-fnv.cc.

References ns3::Hash::Function::Fnv1aImplementation::fnv_32a_buf(), and m_hash32.

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GetHash64()

uint64_t ns3::Hash::Function::Fnv1a::GetHash64	(	const char *	buffer,
		const size_t	size
	)

Compute 64-bit hash of a byte buffer.

Call clear () between calls to GetHash64() to reset the internal state and hash each buffer separately.

If you don't call clear() between calls to GetHash64, you can hash successive buffers. The final return value will be the cumulative hash across all calls.

Parameters

[in]	buffer	pointer to the beginning of the buffer
[in]	size	length of the buffer, in bytes

Returns

64-bit hash of the buffer

Definition at line 763 of file hash-fnv.cc.

References ns3::Hash::Function::Fnv1aImplementation::fnv_64a_buf(), and m_hash64.

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Member Data Documentation

m_hash32

uint32_t ns3::Hash::Function::Fnv1a::m_hash32

private

Cache last hash value, for incremental hashing.

Definition at line 105 of file hash-fnv.h.

Referenced by clear(), and GetHash32().

m_hash64

uint64_t ns3::Hash::Function::Fnv1a::m_hash64

private

Cache last hash value, for incremental hashing.

Definition at line 106 of file hash-fnv.h.

Referenced by clear(), and GetHash64().

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

• src/core/model/hash-fnv.h
• src/core/model/hash-fnv.cc