ultra::hash_t Struct Reference

#include <hash_t.h>

Public Member Functions
	hash_t (std::uint64_t a=0, std::uint64_t b=0)
void	clear () noexcept
	Resets the content of the object.
bool	operator== (const hash_t &) const noexcept=default
	Standard equality operator for hash signature.
bool	operator< (const hash_t &rhs) const noexcept
void	combine (hash_t h) noexcept
bool	empty () const noexcept
	We assume that a string of 128 zero bits means empty.
bool	load (std::istream &)
bool	save (std::ostream &) const

Public Attributes
std::uint64_t	data [2]

Detailed Description

A 128bit unsigned integer used as individual's signature / hash table look-up key.

Member Function Documentation

combine()

void ultra::hash_t::combine ( hash_t h )

inlinenoexcept

Combines another hash into this instance.

Parameters

[in]

h

hash to be combined

Uses prime-number multiplication (data = data * 37 + h), which preserves order sensitivity (unlike commutative XOR).

Note

A default-constructed hash_t ({0, 0}, which evaluates to empty()) acts as a left-identity: starting from an empty accumulator and combining h yields h (0 * 37 + h = h).

Combining an empty hash into an empty hash leaves the result empty (0 * 37 + 0 = 0). Consequently, accumulating any number of empty hashes remains an empty hash.

load()

bool ultra::hash_t::load

(

std::istream &

in

)

Parameters

[in]

in

input stream

Returns

true if hash_t loaded correctly

Note

If the load operation isn't successful the current hash_t isn't changed.

save()

bool ultra::hash_t::save

(

std::ostream &

out

)

const

Parameters

[out]

out

output stream

Returns

true if hash_t was saved correctly

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

• hash_t.h
• hash_t.cc