[Git][ghc/ghc][master] Bignum: add bigNatFromWordArray

[Marge Bot]

 Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC


Commits:
1cde295c by Sylvain Henry at 2020-09-26T05:37:23-04:00
Bignum: add bigNatFromWordArray

Reimplementation of integer-gmp's byteArrayToBigNat#

- - - - -


2 changed files:

- libraries/ghc-bignum/src/GHC/Num/BigNat.hs
- libraries/integer-gmp/src/GHC/Integer/GMP/Internals.hs


Changes:

=====================================
libraries/ghc-bignum/src/GHC/Num/BigNat.hs
=====================================
@@ -1520,3 +1520,42 @@ bigNatFromByteArrayBE# sz  ba moff s =
 bigNatFromByteArray# :: Word# -> ByteArray# -> Word# -> Bool# -> State# s -> (# State# s, BigNat# #)
 bigNatFromByteArray# sz ba off 0# s = bigNatFromByteArrayLE# sz ba off s
 bigNatFromByteArray# sz ba off _  s = bigNatFromByteArrayBE# sz ba off s
+
+
+
+
+-- | Create a BigNat# from a WordArray# containing /n/ limbs in
+-- least-significant-first order.
+--
+-- If possible 'WordArray#', will be used directly (i.e. shared
+-- /without/ cloning the 'WordArray#' into a newly allocated one)
+bigNatFromWordArray# :: WordArray# -> Word# -> BigNat#
+bigNatFromWordArray# wa n0
+   | isTrue# (n `eqWord#` 0##)
+   = bigNatZero# (# #)
+
+   | isTrue# (r `eqWord#` 0##) -- i.e. wa is multiple of limb-size
+   , isTrue# (q `eqWord#` n)
+   = wa
+
+   | True = withNewWordArray# (word2Int# n) \mwa s ->
+               mwaArrayCopy# mwa 0# wa 0# (word2Int# n) s
+   where
+      !(# q, r #) = quotRemWord# (int2Word# (sizeofByteArray# wa))
+                                 WORD_SIZE_IN_BYTES##
+      -- find real size in Words by removing trailing null limbs
+      !n = real_size n0
+      real_size 0## = 0##
+      real_size i
+           | 0## <- bigNatIndex# wa (word2Int# (i `minusWord#` 1##))
+           = real_size (i `minusWord#` 1##)
+      real_size i = i
+
+
+-- | Create a BigNat from a WordArray# containing /n/ limbs in
+-- least-significant-first order.
+--
+-- If possible 'WordArray#', will be used directly (i.e. shared
+-- /without/ cloning the 'WordArray#' into a newly allocated one)
+bigNatFromWordArray :: WordArray# -> Word# -> BigNat
+bigNatFromWordArray wa n = BN# (bigNatFromWordArray# wa n)


=====================================
libraries/integer-gmp/src/GHC/Integer/GMP/Internals.hs
=====================================
@@ -53,6 +53,7 @@ module GHC.Integer.GMP.Internals
 
       -- ** Conversions to/from 'BigNat'
 
+    , byteArrayToBigNat#
     , wordToBigNat
     , wordToBigNat2
     , bigNatToInt
@@ -432,3 +433,8 @@ importIntegerFromByteArray ba off sz endian = case runRW# (I.integerFromByteArra
 exportIntegerToMutableByteArray :: Integer -> MutableByteArray# RealWorld -> Word# -> Int# -> IO Word
 exportIntegerToMutableByteArray i mba off endian = IO (\s -> case I.integerToMutableByteArray# i mba off endian s of
    (# s', r #) -> (# s', W# r #))
+
+
+{-# DEPRECATED byteArrayToBigNat# "Use bigNatFromWordArray instead" #-}
+byteArrayToBigNat# :: ByteArray# -> GmpSize# -> BigNat
+byteArrayToBigNat# ba n = B.bigNatFromWordArray ba (int2Word# n)



View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/1cde295c543e209c3b81256b50e77f3c5132a4ad

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/1cde295c543e209c3b81256b50e77f3c5132a4ad
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