------------------------------------------------------------------------------
-- Copyright (c) 2016, Natacha Porté --
-- --
-- Permission to use, copy, modify, and distribute this software for any --
-- purpose with or without fee is hereby granted, provided that the above --
-- copyright notice and this permission notice appear in all copies. --
-- --
-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES --
-- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF --
-- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR --
-- ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES --
-- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN --
-- ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF --
-- OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. --
------------------------------------------------------------------------------
with GNAT.Perfect_Hash_Generators;
package body Natools.Smaz_Tools.GNAT is
package Perfect_Hash_Generators
renames Standard.GNAT.Perfect_Hash_Generators;
procedure Build_Perfect_Hash
(List : in String_Lists.List;
Package_Name : in String)
is
Seed : Natural := 2;
NK : constant Float := Float (String_Lists.Length (List));
NV : Natural := Natural (String_Lists.Length (List)) * 2 + 1;
Retries_Before_Expand : constant := 2;
begin
for S of List loop
Perfect_Hash_Generators.Insert (S);
end loop;
Expanding_Retries :
loop
Retires_Without_Expand :
for I in 1 .. Retries_Before_Expand loop
begin
Perfect_Hash_Generators.Initialize (Seed, Float (NV) / NK);
Perfect_Hash_Generators.Compute;
exit Expanding_Retries;
exception
when Perfect_Hash_Generators.Too_Many_Tries => null;
end;
Seed := Seed * NV;
end loop Retires_Without_Expand;
NV := NV + 1;
Seed := NV;
end loop Expanding_Retries;
Perfect_Hash_Generators.Produce (Package_Name);
Perfect_Hash_Generators.Finalize;
exception
when others =>
Perfect_Hash_Generators.Finalize;
raise;
end Build_Perfect_Hash;
end Natools.Smaz_Tools.GNAT;