wpi::hashing::detail::hash_combine_recursive_helper Struct Reference

Helper class to manage the recursive combining of hash_combine arguments. More...

#include <wpi/Hashing.h>

Public Member Functions
	hash_combine_recursive_helper ()
	Construct a recursive hash combining helper.
template<typename T >
char *	combine_data (size_t &length, char *buffer_ptr, char *buffer_end, T data)
	Combine one chunk of data into the current in-flight hash.
template<typename T , typename ... Ts>
hash_code	combine (size_t length, char *buffer_ptr, char *buffer_end, const T &arg, const Ts &...args)
	Recursive, variadic combining method.
hash_code	combine (size_t length, char *buffer_ptr, char *buffer_end)
	Base case for recursive, variadic combining.

Public Attributes
char	buffer [64] = {}
hash_state	state
const uint64_t	seed

Detailed Description

Helper class to manage the recursive combining of hash_combine arguments.

This class exists to manage the state and various calls involved in the recursive combining of arguments used in hash_combine. It is particularly useful at minimizing the code in the recursive calls to ease the pain caused by a lack of variadic functions.

Constructor & Destructor Documentation

hash_combine_recursive_helper()

wpi::hashing::detail::hash_combine_recursive_helper::hash_combine_recursive_helper ( )

inline

Construct a recursive hash combining helper.

This sets up the state for a recursive hash combine, including getting the seed and buffer setup.

Member Function Documentation

combine() [1/2]

hash_code wpi::hashing::detail::hash_combine_recursive_helper::combine ( size_t length, char * buffer_ptr, char * buffer_end )

inline

Base case for recursive, variadic combining.

The base case when combining arguments recursively is reached when all arguments have been handled. It flushes the remaining buffer and constructs a hash_code.

combine() [2/2]

template<typename T , typename ... Ts>

hash_code wpi::hashing::detail::hash_combine_recursive_helper::combine ( size_t length, char * buffer_ptr, char * buffer_end, const T & arg, const Ts &... args )

inline

Recursive, variadic combining method.

This function recurses through each argument, combining that argument into a single hash.

combine_data()

template<typename T >

char * wpi::hashing::detail::hash_combine_recursive_helper::combine_data ( size_t & length, char * buffer_ptr, char * buffer_end, T data )

inline

Combine one chunk of data into the current in-flight hash.

This merges one chunk of data into the hash. First it tries to buffer the data. If the buffer is full, it hashes the buffer into its hash_state, empties it, and then merges the new chunk in. This also handles cases where the data straddles the end of the buffer.

Member Data Documentation

buffer

char wpi::hashing::detail::hash_combine_recursive_helper::buffer[64] = {}

seed

const uint64_t wpi::hashing::detail::hash_combine_recursive_helper::seed

state

hash_state wpi::hashing::detail::hash_combine_recursive_helper::state

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

• wpi/Hashing.h