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. More...

virtual void	clear (void)
	Restore initial state. More...

uint32_t	GetHash32 (const char *buffer, const std::size_t size)
	Compute 32-bit hash of a byte buffer. More...

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::Hash::Implementation
	Implementation ()
	Constructor. More...

virtual	~Implementation ()
	Destructor. 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, and total bytes hashed (needed to finalize), for incremental hashing. More...

std::size_t	m_size32
	Cache last hash value, and total bytes hashed (needed to finalize), for incremental hashing. More...


uint64_t	m_hash64 [2]
	murmur3 produces 128-bit hash and state; we use just the first 64-bits. More...

std::size_t	m_size64
	murmur3 produces 128-bit hash and state; we use just the first 64-bits. More...

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 53 of file hash-murmur3.h.

Member Enumeration Documentation

◆ seed

enum ns3::Hash::Function::Murmur3::seed

private

Seed value.

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

Enumerator
SEED

Definition at line 102 of file hash-murmur3.h.

Constructor & Destructor Documentation

◆ Murmur3()

ns3::Hash::Function::Murmur3::Murmur3 ( )

Constructor, clears internal state.

Definition at line 522 of file hash-murmur3.cc.

References clear().

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Member Function Documentation

◆ clear()

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

virtual

Restore initial state.

Implements ns3::Hash::Implementation.

Definition at line 572 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
	)

virtual

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 528 of file hash-murmur3.cc.

References nlohmann::detail::hash(), m_hash32, m_size32, ns3::Hash::Function::Murmur3Implementation::MurmurHash3_x86_32_fin(), and ns3::Hash::Function::Murmur3Implementation::MurmurHash3_x86_32_incr().

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◆ GetHash64()

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

virtual

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 542 of file hash-murmur3.cc.

References nlohmann::detail::hash(), m_hash64, m_size64, ns3::Hash::Function::Murmur3Implementation::MurmurHash3_x86_128_fin(), ns3::Hash::Function::Murmur3Implementation::MurmurHash3_x86_128_incr(), and test-ns3::result.

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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 111 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 117 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 112 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 118 of file hash-murmur3.h.

Referenced by clear(), and GetHash64().

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

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

Public Member Functions

Private Types

Private Attributes

Detailed Description

Member Enumeration Documentation

◆ seed

Constructor & Destructor Documentation

◆ Murmur3()

Member Function Documentation

◆ clear()

◆ GetHash32()

◆ GetHash64()

Member Data Documentation

◆ m_hash32

◆ m_hash64

◆ m_size32

◆ m_size64