[SNIPPET] PseudoRandom_Index

library PseudoRandom

globals
    private integer seed = 1
endglobals

//=====================================================================
//  Return pseudorandom integer that can be used as struct/array index
//  Has full number period (8190).
//  Do not change constants - you will get non-optimal period
//=====================================================================
public function Index takes nothing returns integer 
    set seed = seed * 5 + 17
    set seed = ModuloInteger(seed, 8192)
    if seed == 0 then 
        set seed = 17
    elseif seed == 8191 then
        set seed = 12
    endif
    return seed
endfunction

endlibrary

//==============================================================================
//  Some things need to be random, yet compiled map should always be the same.
//  So we use fixed random seed and pseudorandom number generator.
//  Number is kept positive because we use it in random names.
//  It is also always between [1..8190] so it can be used as array index as well
//==============================================================================
unit PseudoRandom

interface

function GetPseudoRandom(): integer
function GetPrivatePrefix(): string
function GetHashtableKey(): string

//==============================================================================
//  WARNING: Do NOT change any constants in this file.
//==============================================================================
implementation
uses SysUtils

var
  name_seed : integer = 1
  key_seed: integer = 1
  alternator: boolean = false

//==============================================================================
//  PRIVATE: generates next pseudo random number for a given seed.
//==============================================================================
procedure NextPseudoRandom(var seed:integer)
begin
  seed := seed * 5 + 17
  seed := seed mod 8192
  if seed < 0 then seed := seed + 8192
  if seed = 0 then seed := 17
  if seed = 8191 then seed := 12
end

//==============================================================================
// This function is called once for every line of text jasshelper parses.
// It is used to generate random names.
// You always get same random names for same script input.   (pseudorandom)
//==============================================================================
function GetPseudoRandom(): integer
begin
  NextPseudoRandom(name_seed)
  Result := name_seed
end

//==============================================================================
//  Pseudo random hashtable keys.
//==============================================================================
function GetHashtableKey:string
begin
  NextPseudoRandom(key_seed)
  Result := IntToStr(key_seed)
end

//==============================================================================
//  Returns random prefix for private stuff in scopes and libraries.
//==============================================================================
function GetPrivatePrefix():string
begin
  if (GetPseudoRandom() mod 2 = 0) then Result := '__'
  else Result := '___'
end                            

end.