ref: dda68ddb858f384a2d660af1f46b9f928bb048fb
dir: /lib/Data/Integer_Type.hs/
-- Copyright 2023 Lennart Augustsson
-- See LICENSE file for full license.
module Data.Integer_Type(module Data.Integer_Type) where
import Prelude() -- do not import Prelude
import Primitives
import Data.Bool_Type
import Data.List_Type
data Integer = I Sign [Digit]
data Sign = Plus | Minus
type Digit = Int
maxD :: Digit
maxD =
if _wordSize `primIntEQ` 64 then
(2147483648::Int) -- 2^31, this is used so multiplication of two digits doesn't overflow a 64 bit Int
else if _wordSize `primIntEQ` 32 then
(32768::Int) -- 2^15, this is used so multiplication of two digits doesn't overflow a 32 bit Int
else
primError "Integer: unsupported word size"
-- Sadly, we also need a bunch of functions.
_intToInteger :: Int -> Integer
_intToInteger i | i `primIntGE` 0 = I Plus (f i)
| i `primIntEQ` ni = I Minus [0::Int,0::Int,2::Int] -- we are at minBound::Int.
| True = I Minus (f ni)
where
ni = (0::Int) `primIntSub` i
f :: Int -> [Int]
f x = if primIntEQ x (0::Int) then [] else primIntRem x maxD : f (primIntQuot x maxD)
_integerToInt :: Integer -> Int
_integerToInt (I sign ds) = s `primIntMul` i
where
i =
case ds of
[] -> 0::Int
[d1] -> d1
[d1,d2] -> d1 `primIntAdd` (maxD `primIntMul` d2)
d1:d2:d3:_ -> d1 `primIntAdd` (maxD `primIntMul` (d2 `primIntAdd` (maxD `primIntMul` d3)))
s =
case sign of
Plus -> 1::Int
Minus -> 0 `primIntSub` 1
_wordToInteger :: Word -> Integer
_wordToInteger i = I Plus (f i)
where
f :: Word -> [Int]
f x = if x `primWordEQ` (0::Word) then [] else primWordToInt (primWordRem x (primIntToWord maxD)) : f (primWordQuot x (primIntToWord maxD))
_integerToWord :: Integer -> Word
_integerToWord x = primIntToWord (_integerToInt x)
_integerToDouble :: Integer -> Double
_integerToDouble (I sign ds) = s `primDoubleMul` loop ds
where
loop [] = 0.0::Double
loop (i : is) = primDoubleFromInt i `primDoubleAdd` (primDoubleFromInt maxD `primDoubleMul` loop is)
s =
case sign of
Plus -> 1.0::Double
Minus -> 0.0 `primDoubleSub` 1.0