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Add chunks-to-builder function

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This commit is contained in:
Andrew Martin 2023-03-29 11:44:01 -04:00
parent 0405c0eb88
commit b8e4656334
1 changed files with 26 additions and 2 deletions
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28
src/Data/Bytes/Builder.hs
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@ -22,6 +22,7 @@ module Data.Bytes.Builder
, putManyConsLength
-- * Materialized Byte Sequences
, bytes
, chunks
, copy
, copyCons
, copy2
@ -153,7 +154,7 @@ import Data.Bytes.Builder.Unsafe (Commits(Initial,Mutable,Immutable))
import Data.Bytes.Builder.Unsafe (commitsOntoChunks)
import Data.Bytes.Builder.Unsafe (reverseCommitsOntoChunks)
import Data.Bytes.Builder.Unsafe (stringUtf8,cstring,fromEffect)
import Data.Bytes.Chunks (Chunks(ChunksNil))
import Data.Bytes.Chunks (Chunks(ChunksCons,ChunksNil))
import Data.Bytes.Types (Bytes(Bytes),MutableBytes(MutableBytes))
import Data.ByteString.Short.Internal (ShortByteString(SBS))
import Data.Char (ord)
@ -166,7 +167,7 @@ import Data.Word (Word64,Word32,Word16,Word8)
import Data.Word.Zigzag (toZigzagNative,toZigzag32,toZigzag64)
import Foreign.C.String (CStringLen)
import GHC.ByteOrder (ByteOrder(BigEndian,LittleEndian),targetByteOrder)
import GHC.Exts (Addr#,(*#),oneShot)
import GHC.Exts (MutableByteArray#,Addr#,(*#),oneShot)
import GHC.Exts (Int(I#),Char(C#),Int#,State#,ByteArray#,(>=#))
import GHC.Exts (RealWorld,(+#),(-#),(<#))
import GHC.Integer.Logarithms.Compat (integerLog2#)
@ -401,6 +402,29 @@ bytes (Bytes (ByteArray src# ) (I# soff# ) (I# slen# )) = Builder
(# s1, buf0, off0 +# slen#, len0 -# slen#, cs0 #)
)
-- | Paste byte chunks into a builder.
chunks :: Chunks -> Builder
{-# noinline chunks #-}
chunks xs0 =
-- Implementation note: It would probably be good to begin with a
-- goCopying phase before switching to goInserting. If the total
-- size of the chunks is small, we could end up just copying
-- everything into the existing buffer, which would be nice.
-- Note: This function needs a test in the test suite.
Builder $ \buf0 off0 len0 cs0 s0 -> case xs0 of
ChunksNil -> (# s0, buf0, off0, len0, cs0 #)
ChunksCons{} -> goInserting xs0 cs0 s0
where
-- Notice that goNoncopying does not take a buffer as an argument. At the
-- very end, we create a 128-byte buffer with nothing in it and present
-- that as the new buffer. We *cannot* simply reuse the old buffer with
-- the length set to zero because commitDistance1 would get confused.
goInserting :: Chunks -> Commits s -> State# s -> (# State# s, MutableByteArray# s, Int#, Int#, Commits s #)
goInserting ChunksNil !cs s0 = case Exts.newByteArray# 128# s0 of
(# s1, buf1 #) -> (# s1, buf1, 0#, 128#, cs #)
goInserting (ChunksCons (Bytes (ByteArray b) (I# off) (I# len)) ys) !cs s0 =
goInserting ys (Immutable b off len cs) s0
-- | Create a builder from a byte sequence. This always results in a
-- call to @memcpy@. This is beneficial when the byte sequence is
-- known to be small (less than 256 bytes).