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

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

#include <Hashing.h>

Public Member Functions

 hash_combine_recursive_helper ()
 Construct a recursive hash combining helper. More...
 
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. More...
 
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. More...
 
hash_code combine (size_t length, char *buffer_ptr, char *buffer_end)
 Base case for recursive, variadic combining. More...
 

Public Attributes

char buffer [64]
 
hash_state state
 
const size_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

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

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.

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.

template<typename T >
char* wpi::hashing::detail::hash_combine_recursive_helper::combine_data ( size_t &  length,
char *  buffer_ptr,
char *  buffer_end,
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.


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