#! Integer kinds to be considered during templating
#:set INT_KINDS = ["int8", "int16", "int32", "int64"]
module stdlib_hash_64bit
use, intrinsic :: iso_fortran_env, only : &
character_storage_size
use stdlib_kinds, only: &
dp, &
int8, &
int16, &
int32, &
int64
implicit none
private
integer, parameter, public :: &
int_hash = int64
!! The number of bits in the output hash
! The number of bits used by each integer type
integer, parameter, public :: &
! Should be 8
bits_int8 = bit_size(0_int8), &
! Should be 16
bits_int16 = bit_size(0_int16), &
! Should be 32
bits_int32 = bit_size(0_int32), &
! Should be 64
bits_int64 = bit_size(0_int64)
integer, parameter, public :: &
! Should be 1
bytes_int8 = bits_int8/bits_int8, &
! Should be 2
bytes_int16 = bits_int16/bits_int8, &
! Should be 4
bytes_int32 = bits_int32/bits_int8, &
! Should be 8
bytes_int64 = bits_int64/bits_int8
integer, parameter, public :: &
bits_char = character_storage_size, &
bytes_char = bits_char/bits_int8
! Dealing with different endians
logical, parameter, public :: &
little_endian = ( 1 == transfer( [1_int8, 0_int8], 0_int16) )
public :: &
fibonacci_hash, &
fnv_1_hash, &
fnv_1a_hash, &
new_pengy_hash_seed, &
new_spooky_hash_seed, &
odd_random_integer, &
pengy_hash, &
spooky_hash, &
spookyhash_128, &
universal_mult_hash
! pow64_over_phi is the odd number that most closely approximates 2**64/phi,
! where phi is the golden ratio 1.618...
integer(int64), parameter :: &
pow64_over_phi = int(z'9E3779B97F4A7C15', int64)
integer(int_hash), parameter :: &
two_32 = 2_int_hash**32
! constants used by Bob Jenkins' SpookyHash
integer(int32), parameter :: &
sc_numvars = 12, &
sc_blocksize = sc_numvars*8, &
sc_buffsize = 2*sc_blocksize, &
sc_constsub = int(z'deadbeef', int32)
! twos complement "deadbeef"
integer(int64), parameter :: &
sc_const = transfer( [sc_constsub, sc_constsub], 0_int64 )
type :: spooky_subhash
integer(int8) :: data(0:2*sc_blocksize-1)
integer(int64) :: state(0:sc_numvars-1)
integer(int64) :: length
integer(int16) :: remainder
end type spooky_subhash
interface fnv_1_hash
!! Version: experimental
!!
!! FNV_1 interfaces
!! ([Specification](../page/specs/stdlib_hash_procedures.html#fnv_1-calculates-a-hash-code-from-a-key))
#:for k1 in INT_KINDS
pure module function ${k1}$_fnv_1( key ) result(hash_code)
!! FNV_1 hash function for rank 1 arrays of kind ${k1}$
integer(${k1}$), intent(in) :: key(:)
integer(int_hash) :: hash_code
end function ${k1}$_fnv_1
#:endfor
elemental module function character_fnv_1( key ) result(hash_code)
!! FNV_1 hash function for character strings
character(*), intent(in) :: key
integer(int_hash) :: hash_code
end function character_fnv_1
end interface fnv_1_hash
interface fnv_1a_hash
!! Version: experimental
!!
!! FNV_1A interfaces
!! ([Specification](../page/specs/stdlib_hash_procedures.html#fnv_1a-calculates-a-hash-code-from-a-key))
#:for k1 in INT_KINDS
pure module function ${k1}$_fnv_1a( key ) result(hash_code)
!! FNV_1A hash function for rank 1 arrays of kind ${k1}$
integer(${k1}$), intent(in) :: key(:)
integer(int_hash) :: hash_code
end function ${k1}$_fnv_1a
#:endfor
elemental module function character_fnv_1a( key ) result(hash_code)
!! FNV_1A hash function for character strings
character(*), intent(in) :: key
integer(int_hash) :: hash_code
end function character_fnv_1a
end interface fnv_1a_hash
interface spooky_hash
!! Version: experimental
!!
!! SPOOKY_HASH interfaces
!!([Specification](../page/specs/stdlib_hash_procedures.html#spooky_hash-maps-a-character-string-or-integer-vector-to-an-integer))
#:for k1 in INT_KINDS
module function ${k1}$_spooky_hash( key, seed ) &
result(hash_code)
!! SPOOKY HASH function for rank 1 arrays of kind ${k1}$
integer(${k1}$), intent(in) :: key(0:)
integer(int_hash), intent(in) :: seed(2)
integer(int_hash) :: hash_code(2)
end function ${k1}$_spooky_hash
#:endfor
module function character_spooky_hash( key, seed ) &
result(hash_code)
!! SPOOKY hash function for character strings
character(*), intent(in) :: key
integer(int_hash), intent(in) :: seed(2)
integer(int_hash) :: hash_code(2)
end function character_spooky_hash
end interface spooky_hash
interface
module subroutine spookyHash_128( key, hash_inout )
!! Version: experimental
!!
integer(int8), intent(in), target :: key(0:)
integer(int_hash), intent(inout) :: hash_inout(2)
end subroutine spookyHash_128
end interface
interface spooky_init
!! Version: experimental
!!
pure module subroutine spookysubhash_init( self, seed )
type(spooky_subhash), intent(out) :: self
integer(int_hash), intent(in) :: seed(2)
end subroutine spookysubhash_init
end interface spooky_init
interface spooky_update
module subroutine spookyhash_update( spooky, key )
!! Version: experimental
!!
type(spooky_subhash), intent(inout) :: spooky
integer(int8), intent(in) :: key(0:)
end subroutine spookyhash_update
end interface spooky_update
interface spooky_final
module subroutine spookyhash_final(spooky, hash_code)
!! Version: experimental
!!
type(spooky_subhash), intent(inout) :: spooky
integer(int_hash), intent(inout) :: hash_code(2)
end subroutine spookyhash_final
end interface spooky_final
interface
module subroutine new_spooky_hash_seed( seed )
!! Version: experimental
!!
!! Random seed generator for SPOOKY_HASH
integer(int64), intent(inout) :: seed(2)
end subroutine new_spooky_hash_seed
end interface
interface pengy_hash
!! Version: experimental
!!
!! PENGY_HASH interfaces
!! ([Specification](../page/specs/stdlib_hash_procedures.html#pengy_hash-maps-a-character-string-or-integer-vector-to-an-integer))
#:for k1 in INT_KINDS
pure module function ${k1}$_pengy_hash( key, seed ) result(hash_code)
!! PENGY_HASH hash function for rank 1 array keys of kind ${k1}$
integer(${k1}$), intent(in) :: key(:)
integer(int32), intent(in) :: seed
integer(int64) :: hash_code
end function ${k1}$_pengy_hash
#:endfor
elemental module function character_pengy_hash( key, seed ) &
result(hash_code)
!! MIR HASH STRICT function for character strings
character(*), intent(in) :: key
integer(int32), intent(in) :: seed
integer(int64) :: hash_code
end function character_pengy_hash
end interface pengy_hash
interface
module subroutine new_pengy_hash_seed( seed )
!! Version: experimental
!!
!! Random seed generator for MIR_HASH_STRICT
integer(int32), intent(inout) :: seed
end subroutine new_pengy_hash_seed
end interface
contains
elemental function fibonacci_hash( key, nbits ) result( sample )
!! Version: experimental
!!
!! Maps the 64 bit integer `key` to an unsigned integer value with only `nbits`
!! bits where `nbits` is less than 64
!! ([Specification](../page/specs/stdlib_hash_procedures.html#fibonacci_hash-maps-an-integer-to-a-smaller-number-of-bits_1))
integer(int64), intent(in) :: key
integer, intent(in) :: nbits
integer(int64) :: sample
sample = ishft( key*pow64_over_phi, -64 + nbits )
end function fibonacci_hash
elemental function universal_mult_hash( key, seed, nbits ) result( sample )
!! Version: experimental
!!
!! Uses the "random" odd 64 bit integer `seed` to map the 64 bit integer `key` to
!! an unsigned integer value with only `nbits` bits where `nbits` is less than 64.
!! ([Specification](../page/specs/stdlib_hash_procedures.html#universal_mult_hash-maps-an-integer-to-a-smaller-number-of-bits_1))
integer(int64), intent(in) :: key
integer(int64), intent(in) :: seed
integer, intent(in) :: nbits
integer(int64) :: sample
sample = ishft( key*seed, -64 + nbits )
end function universal_mult_hash
subroutine odd_random_integer( harvest )
!! Version: experimental
!!
!! Returns a 64 bit pseudo random integer, `harvest`, distributed uniformly over
!! the odd integers of the 64 bit kind.
!! ([Specification](../page/specs/stdlib_hash_procedures.html#odd_random_integer-returns-odd-integer))
integer(int64), intent(out) :: harvest
real(dp) :: sample(2)
integer(int32) :: part(2)
call random_number( sample )
part = int( floor( sample * 2_int64**32, int64 ) - 2_int64**31, int32 )
harvest = transfer( part, harvest )
harvest = ishft( harvest, 1 ) + 1_int64
end subroutine odd_random_integer
subroutine random_integer( harvest )
!! Version: experimental
!!
!! Returns a 64 bit pseudo random integer, `harvest`, distributed uniformly over
!! the values of the 64 bit kind.
integer(int64), intent(out) :: harvest
real(dp) :: sample(2)
integer(int32) :: part(2)
call random_number( sample )
part = int( floor( sample * 2_int64**32, int64 ) - 2_int64**31, int32 )
harvest = transfer( part, harvest )
end subroutine random_integer
end module stdlib_hash_64bit
