module DeferredFolds.Util.TextArray
where

import DeferredFolds.Prelude
import qualified Data.Text.Internal as TextInternal
import qualified Data.Text.Internal.Encoding.Utf16 as TextUtf16
import qualified Data.Text.Internal.Unsafe.Char as TextChar
import qualified Data.Text.Array as TextArray


{-|
Same as 'Data.Text.Unsafe.iter',
but operates on the array directly,
uses a continuation and passes the next offset to it instead of delta.
-}
{-# INLINE iter #-}
iter :: TextArray.Array -> Int -> (Char -> Int -> a) -> a
iter :: Array -> Int -> (Char -> Int -> a) -> a
iter Array
arr Int
offset Char -> Int -> a
cont =
  let
    b1 :: Word16
b1 =
      Array -> Int -> Word16
TextArray.unsafeIndex Array
arr Int
offset
    in if Word16
b1 Word16 -> Word16 -> Bool
forall a. Ord a => a -> a -> Bool
>= Word16
0xd800 Bool -> Bool -> Bool
&& Word16
b1 Word16 -> Word16 -> Bool
forall a. Ord a => a -> a -> Bool
<= Word16
0xdbff
      then let
        b2 :: Word16
b2 =
          Array -> Int -> Word16
TextArray.unsafeIndex Array
arr (Int -> Int
forall a. Enum a => a -> a
succ Int
offset)
        char :: Char
char =
          Word16 -> Word16 -> Char
TextUtf16.chr2 Word16
b1 Word16
b2
        in Char -> Int -> a
cont Char
char (Int
offset Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
2)
      else
        Char -> Int -> a
cont (Word16 -> Char
TextChar.unsafeChr Word16
b1) (Int
offset Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
1)