ns3::Hash::Function::Murmur3 Class Reference

Murmur3 hash function implementation. More...

#include "hash-murmur3.h"

Inheritance diagram for ns3::Hash::Function::Murmur3:

Collaboration diagram for ns3::Hash::Function::Murmur3:

Public Member Functions
	Murmur3 ()
	Constructor, clears internal state.
void	clear () override
	Restore initial state.
uint32_t	GetHash32 (const char *buffer, const std::size_t size) override
	Compute 32-bit hash of a byte buffer.
uint64_t	GetHash64 (const char *buffer, const std::size_t size) override
	Compute 64-bit hash of a byte buffer.
Public Member Functions inherited from ns3::Hash::Implementation
	Implementation ()
	Constructor.
virtual	~Implementation ()
	Destructor.
Public Member Functions inherited from ns3::SimpleRefCount< Implementation >
	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.

Private Attributes
uint32_t	m_hash32
	Cache last hash value, and total bytes hashed (needed to finalize), for incremental hashing.
std::size_t	m_size32
	Cache last hash value, and total bytes hashed (needed to finalize), for incremental hashing.
uint64_t	m_hash64 [2]
	murmur3 produces 128-bit hash and state; we use just the first 64-bits.
std::size_t	m_size64
	murmur3 produces 128-bit hash and state; we use just the first 64-bits.

Static Private Attributes
static constexpr auto	SEED {0x8BADF00D}
	Seed value.

Detailed Description

Murmur3 hash function implementation.

Adapted from http://code.google.com/p/smhasher/

MurmurHash3 was written by Austin Appleby, and is placed in the public domain. The author hereby disclaims copyright to this source code.

Note - The x86 and x64 versions do not produce the same results, as the algorithms are optimized for their respective platforms. You can still compile and run any of them on any platform, but your performance with the non-native version will be less than optimal.

Definition at line 44 of file hash-murmur3.h.

Constructor & Destructor Documentation

Murmur3()

ns3::Hash::Function::Murmur3::Murmur3

(

)

Constructor, clears internal state.

Definition at line 512 of file hash-murmur3.cc.

References clear().

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Member Function Documentation

clear()

void ns3::Hash::Function::Murmur3::clear ( )

overridevirtual

Restore initial state.

Implements ns3::Hash::Implementation.

Definition at line 559 of file hash-murmur3.cc.

References m_hash32, m_hash64, m_size32, m_size64, and SEED.

Referenced by Murmur3().

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GetHash32()

uint32_t ns3::Hash::Function::Murmur3::GetHash32 ( const char * buffer, const std::size_t size )

overridevirtual

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

Implements ns3::Hash::Implementation.

Definition at line 518 of file hash-murmur3.cc.

References m_hash32, and m_size32.

GetHash64()

uint64_t ns3::Hash::Function::Murmur3::GetHash64 ( const char * buffer, const std::size_t size )

overridevirtual

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

Reimplemented from ns3::Hash::Implementation.

Definition at line 531 of file hash-murmur3.cc.

References m_hash64, and m_size64.

Member Data Documentation

m_hash32

uint32_t ns3::Hash::Function::Murmur3::m_hash32

private

Cache last hash value, and total bytes hashed (needed to finalize), for incremental hashing.

Definition at line 100 of file hash-murmur3.h.

Referenced by clear(), and GetHash32().

m_hash64

uint64_t ns3::Hash::Function::Murmur3::m_hash64[2]

private

murmur3 produces 128-bit hash and state; we use just the first 64-bits.

Definition at line 106 of file hash-murmur3.h.

Referenced by clear(), and GetHash64().

m_size32

std::size_t ns3::Hash::Function::Murmur3::m_size32

private

Cache last hash value, and total bytes hashed (needed to finalize), for incremental hashing.

Definition at line 101 of file hash-murmur3.h.

Referenced by clear(), and GetHash32().

m_size64

std::size_t ns3::Hash::Function::Murmur3::m_size64

private

murmur3 produces 128-bit hash and state; we use just the first 64-bits.

Definition at line 107 of file hash-murmur3.h.

Referenced by clear(), and GetHash64().

SEED

auto ns3::Hash::Function::Murmur3::SEED {0x8BADF00D}

staticconstexprprivate

Seed value.

This has to be a constant for all MPI ranks to generate the same hash from the same string.

Definition at line 93 of file hash-murmur3.h.

Referenced by clear().

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

• src/core/model/hash-murmur3.h
• src/core/model/hash-murmur3.cc