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struct | hash_combine_recursive_helper |
Helper class to manage the recursive combining of hash_combine arguments. More... | |
struct | hash_state |
The intermediate state used during hashing. More... | |
struct | is_hashable_data |
Trait to indicate whether a type's bits can be hashed directly. More... | |
struct | is_hashable_data< std::pair< T, U > > |
Functions | |
uint64_t | fetch64 (const char *p) |
uint32_t | fetch32 (const char *p) |
uint64_t | rotate (uint64_t val, size_t shift) |
Bitwise right rotate. | |
uint64_t | shift_mix (uint64_t val) |
uint64_t | hash_16_bytes (uint64_t low, uint64_t high) |
uint64_t | hash_1to3_bytes (const char *s, size_t len, uint64_t seed) |
uint64_t | hash_4to8_bytes (const char *s, size_t len, uint64_t seed) |
uint64_t | hash_9to16_bytes (const char *s, size_t len, uint64_t seed) |
uint64_t | hash_17to32_bytes (const char *s, size_t len, uint64_t seed) |
uint64_t | hash_33to64_bytes (const char *s, size_t len, uint64_t seed) |
uint64_t | hash_short (const char *s, size_t length, uint64_t seed) |
uint64_t | get_execution_seed () |
In LLVM_ENABLE_ABI_BREAKING_CHECKS builds, the seed is non-deterministic per process (address of a function in LLVMSupport) to prevent having users depend on the particular hash values. | |
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std::enable_if_t< is_hashable_data< T >::value, T > | get_hashable_data (const T &value) |
Helper to get the hashable data representation for a type. | |
template<typename T > | |
std::enable_if_t<!is_hashable_data< T >::value, size_t > | get_hashable_data (const T &value) |
Helper to get the hashable data representation for a type. | |
template<typename T > | |
bool | store_and_advance (char *&buffer_ptr, char *buffer_end, const T &value, size_t offset=0) |
Helper to store data from a value into a buffer and advance the pointer into that buffer. | |
template<typename InputIteratorT > | |
hash_code | hash_combine_range_impl (InputIteratorT first, InputIteratorT last) |
Implement the combining of integral values into a hash_code. | |
template<typename ValueT > | |
std::enable_if_t< is_hashable_data< ValueT >::value, hash_code > | hash_combine_range_impl (ValueT *first, ValueT *last) |
Implement the combining of integral values into a hash_code. | |
hash_code | hash_integer_value (uint64_t value) |
Helper to hash the value of a single integer. | |
Variables | |
static constexpr uint64_t | k0 = 0xc3a5c85c97cb3127ULL |
Some primes between 2^63 and 2^64 for various uses. | |
static constexpr uint64_t | k1 = 0xb492b66fbe98f273ULL |
static constexpr uint64_t | k2 = 0x9ae16a3b2f90404fULL |
static constexpr uint64_t | k3 = 0xc949d7c7509e6557ULL |
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In LLVM_ENABLE_ABI_BREAKING_CHECKS builds, the seed is non-deterministic per process (address of a function in LLVMSupport) to prevent having users depend on the particular hash values.
On platforms without ASLR, this is still likely non-deterministic per build.
std::enable_if_t< is_hashable_data< T >::value, T > wpi::hashing::detail::get_hashable_data | ( | const T & | value | ) |
Helper to get the hashable data representation for a type.
This variant is enabled when the type itself can be used.
std::enable_if_t<!is_hashable_data< T >::value, size_t > wpi::hashing::detail::get_hashable_data | ( | const T & | value | ) |
Helper to get the hashable data representation for a type.
This variant is enabled when we must first call hash_value and use the result as our data.
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hash_code wpi::hashing::detail::hash_combine_range_impl | ( | InputIteratorT | first, |
InputIteratorT | last ) |
std::enable_if_t< is_hashable_data< ValueT >::value, hash_code > wpi::hashing::detail::hash_combine_range_impl | ( | ValueT * | first, |
ValueT * | last ) |
Implement the combining of integral values into a hash_code.
This overload is selected when the value type of the iterator is integral and when the input iterator is actually a pointer. Rather than computing a hash_code for each object and then combining them, this (as an optimization) directly combines the integers. Also, because the integers are stored in contiguous memory, this routine avoids copying each value and directly reads from the underlying memory.
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Helper to hash the value of a single integer.
Overloads for smaller integer types are not provided to ensure consistent behavior in the presence of integral promotions. Essentially, "hash_value('4')" and "hash_value('0' + 4)" should be the same.
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Bitwise right rotate.
Normally this will compile to a single instruction, especially if the shift is a manifest constant.
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bool wpi::hashing::detail::store_and_advance | ( | char *& | buffer_ptr, |
char * | buffer_end, | ||
const T & | value, | ||
size_t | offset = 0 ) |
Helper to store data from a value into a buffer and advance the pointer into that buffer.
This routine first checks whether there is enough space in the provided buffer, and if not immediately returns false. If there is space, it copies the underlying bytes of value into the buffer, advances the buffer_ptr past the copied bytes, and returns true.
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Some primes between 2^63 and 2^64 for various uses.
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