FNV_1_HASH
and FNV_1A_Hash
are translations to Fortran 2008 of the
FNV-1
and FNV-1a
hash functions of Glenn Fowler, Landon Curt Noll,
and Phong Vo, that has been released into the public domain. Permission
has been granted, by Landon Curt Noll, for the use of these algorithms
in the Fortran Standard Library. A description of these functions is
available at https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function.
!!------------------------------------------------------------------------------ !! `FNV_1_HASH` and `FNV_1A_Hash` are translations to Fortran 2008 of the !! `FNV-1` and `FNV-1a` hash functions of Glenn Fowler, Landon Curt Noll, !! and Phong Vo, that has been released into the public domain. Permission !! has been granted, by Landon Curt Noll, for the use of these algorithms !! in the Fortran Standard Library. A description of these functions is !! available at https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function. !!------------------------------------------------------------------------------ !#! Integer kinds to be considered during templating #:set INT_KINDS = ["int16", "int32", "int64"] submodule(stdlib_hash_32bit) stdlib_hash_32bit_fnv !! An implementation of the FNV hashes 1 and 1a of Glenn Fowler, Landon Curt !! Noll, and Kiem-Phong-Vo, !! https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function implicit none integer(int_hash), parameter :: & offset_basis = int( z'811C9DC5', int_hash ), & prime = int( z'01000193', int_hash ) contains pure module function int8_fnv_1( key ) result(hash_code) !! The original FNV-1 8-bit key algorithm. integer(int8), intent(in) :: key(:) integer(int_hash) :: hash_code integer(int64) :: i hash_code = offset_basis do i=1_int64, size(key, kind=int64) hash_code = hash_code * prime if ( little_endian ) then hash_code = ieor( hash_code, & transfer( [key(i), 0_int8, 0_int8, 0_int8], & 0_int_hash ) ) else hash_code = ieor( hash_code, & transfer( [0_int8, 0_int8, 0_int8, key(i)], & 0_int_hash ) ) end if end do end function int8_fnv_1 #:for k1 in INT_KINDS pure module function ${k1}$_fnv_1( key ) result(hash_code) ! A ${k1}$ array key wrapper for the FNV-1 algorithm. integer(${k1}$), intent(in) :: key(:) integer(int_hash) :: hash_code hash_code = int8_fnv_1( transfer( key, 0_int8, & bytes_${k1}$* & size( key, kind=int64 ) ) ) end function ${k1}$_fnv_1 #:endfor elemental module function character_fnv_1( key ) result(hash_code) ! A default character key wrapper for the FNV-1 algorithm. character(*), intent(in) :: key integer(int_hash) :: hash_code hash_code = int8_fnv_1( transfer( key, & 0_int8, & bytes_char* & len(key, kind=int64) ) ) end function character_fnv_1 pure module function int8_fnv_1a( key ) result(hash_code) !! The original FNV-1a 8-bit key algorithm. integer(int8), intent(in) :: key(:) integer(int_hash) :: hash_code integer(int64) :: i hash_code = offset_basis do i=1_int64, size(key, kind=int64) if ( little_endian ) then hash_code = ieor( hash_code, & transfer( [key(i), 0_int8, 0_int8, 0_int8], & 0_int_hash ) ) else hash_code = ieor( hash_code, & transfer( [0_int8, 0_int8, 0_int8, key(i)], & 0_int_hash ) ) end if hash_code = hash_code * prime end do end function int8_fnv_1a #:for k1 in INT_KINDS pure module function ${k1}$_fnv_1a( key ) result(hash_code) ! A ${k1}$ array key wrapper for the FNV-1a algorithm. integer(${k1}$), intent(in) :: key(:) integer(int_hash) :: hash_code hash_code = int8_fnv_1a( transfer( key, 0_int8, & bytes_${k1}$* & size(key, kind=int64)) ) end function ${k1}$_fnv_1a #:endfor elemental module function character_fnv_1a( key ) result(hash_code) ! A default character key wrapper for the FNV-1 algorithm. character(*), intent(in) :: key integer(int_hash) :: hash_code hash_code = int8_fnv_1a( transfer( key, 0_int8, & (bits_char/bits_int8)* & len(key, kind=int64) ) ) end function character_fnv_1a end submodule stdlib_hash_32bit_fnv