@@ -5,402 +5,152 @@
5-- | Writing to an `ArrayBuffer` is an `Effect`ful activity, so most
5-- | Writing to an `ArrayBuffer` is an `Effect`ful activity, so most
6-- | functions in this module must be run in a `MonadEffect` context.
6-- | functions in this module must be run in a `MonadEffect` context.
8−-- | For operations for working with `ArrayBuffer`, see
8+-- | For other operations for working with `ArrayBuffer`, see
10-- | [`Data.ArrayBuffer.ArrayBuffer`](https://pursuit.purescript.org/packages/purescript-arraybuffer/docs/Data.ArrayBuffer.ArrayBuffer)
10-- | [`Data.ArrayBuffer.ArrayBuffer`](https://pursuit.purescript.org/packages/purescript-arraybuffer/docs/Data.ArrayBuffer.ArrayBuffer)
11−-- | in package __purescript-arraybuffer__.
11+-- | in package __arraybuffer__.
12module Data.ArrayBuffer.Builder
12module Data.ArrayBuffer.Builder
15−, execPutM
15+ , execPutM
16−, execPut
16+ , execPut
17−, putArrayBuffer
18+ , putArrayBuffer
18−, putUint8
21+ , putUint8
19−, putInt8
22+ , putInt8
20−, putUint16be
23+ , putUint16be
21−, putUint16le
24+ , putUint16le
22−, putInt16be
25+ , putInt16be
23−, putInt16le
26+ , putInt16le
24−, putUint32be
27+ , putUint32be
25−, putUint32le
28+ , putUint32le
26−, putInt32be
29+ , putInt32be
27−, putInt32le
30+ , putInt32le
28−, putFloat32be
31+ , putFloat32be
29−, putFloat32le
32+ , putFloat32le
30−, putFloat64be
33+ , putFloat64be
31−, putFloat64le
34+ , putFloat64le
32−, Builder
35+ , module Data.ArrayBuffer.Builder.Internal
54import Prelude
38import Prelude
40+import Control.Monad.Rec.Class (class MonadRec)
56−import Control.Monad.Writer.Trans (WriterT, execWriterT, tell)
41+import Control.Monad.Writer.Trans (WriterT, execWriterT, tell, lift)
57−import Data.ArrayBuffer.ArrayBuffer as AB
42+import Data.ArrayBuffer.Builder.Internal (Builder, DataBuff(..), length, toView, (<>>))
58−import Data.ArrayBuffer.DataView as DV
59−import Data.ArrayBuffer.Typed as AT
43+import Data.ArrayBuffer.Builder.Internal as Internal
60−import Data.ArrayBuffer.Types (ArrayBuffer, Uint8Array)
44+import Data.ArrayBuffer.Types (ArrayBuffer, DataView)
61import Data.Float32 (Float32)
45import Data.Float32 (Float32)
62−import Data.Maybe (Maybe(..))
63import Data.UInt (UInt)
46import Data.UInt (UInt)
64import Effect (Effect)
47import Effect (Effect)
65−import Effect.Class (class MonadEffect, liftEffect)
48+import Effect.Class (class MonadEffect)
67−-- | The `PutM` monad is a Writer transformer monad which
50+-- | The `PutM` monad is a `WriterT Builder` transformer monad which
68−-- | [gives us access to do-notation](https://wiki.haskell.org/Do_notation_considered_harmful#Library_design)
51+-- | gives us do-notation for the `Builder` monoid. The base monad must be
69−-- | for building `ArrayBuffer`s.
52+-- | a `MonadEffect`.
54+-- | To append `Builder`s in this monad call `tell`, or any of the `put*`
55+-- | functions in this module.
70type PutM = WriterT Builder
56type PutM = WriterT Builder
72−-- | `Put` monad is the non-transformer version of `PutM`.
58+-- | The `PutM` type reified to `Effect`, in other words `WriterT Builder Effect`.
73type Put = PutM Effect
59type Put = PutM Effect
75−-- | Monoidal builder for `ArrayBuffer`s.
61+-- | Build an `ArrayBuffer` with do-notation in any `MonadEffect`. *O(n)* Stack-safe.
76−-- |
62+execPutM :: forall m. MonadEffect m => MonadRec m => PutM m Unit -> m ArrayBuffer
77−-- | ### Left-associative `<>>` append operator
63+execPutM = Internal.execBuilder <=< execWriterT
65+-- | Build an `ArrayBuffer` with do-notation in `Effect`. *O(n)* Stack-safe.
66+execPut :: Put Unit -> Effect ArrayBuffer
69+-- | Build up a sub-`Builder` without `tell`ing it to the `Writer` yet.
79−-- | __TL;DR__ You probably don't want to use the `Builder` monoid directly
71+-- | One case where we might want to call a `subBuilder` is when
80−-- | in your code, it’s better to use the `PutM` monad with do-notation instead.
72+-- | serializing length-prefixed messages in some protocol. In that case,
73+-- | we must serialize the message first, calculate the message length,
74+-- | append the message length, and then append the message.
82−-- | The `Builder` monoid in this library is efficient when we `snoc` single
76+-- | In a `PutM` monad do-block, we can
83−-- | items onto the end of it, or when we only `cons` single items to the
84−-- | beginning, but it can be less efficient when we are mixing `cons` and
86−-- | This matters when we're appending three or more `Builder`s
87−-- | in one associative expression, because the
88−-- | `Semigroup` append operator `<>` is right-associative.
90−-- | To solve this, we provide an operator `<>>` for appending `Builders`.
91−-- | `<>>` is exactly the same as `<>`, but left-associative.
92−-- | This only matters when we're chaining together three
93−-- | or more `Builder`s in a single associative expression.
96−-- | builder₁ <> builder₂ <> builder₃
98−-- | we should always prefer to
101−-- | builder₁ <>> builder₂ <>> builder₃
79+-- | do
102−-- | ```
80+-- | messageBuilder <- subBuilder $ do
103−-- | so that we get the efficient
81+-- | putField1
104−-- | `snoc`ing of `Builder`s.
105−-- |
82+-- | putField2
106−-- | If we build our `ArrayBuffer`s with the `PutM` monad instead of appending by
107−-- | using the `Semigroup` instance of `Builder`, then we always get the efficient
110−data Builder
84+-- | putInt32be $ length messageBuilder
111− = Node Builder ArrayBuffer Builder
85+-- | tell messageBuilder
113−
87+subBuilder :: forall m. Monad m => PutM m Unit -> PutM m Builder
114−instance semigroupBuilder :: Semigroup Builder where
115− append Null Null = Null
118− append l (Node Null rx rr) = Node l rx rr -- this is the snoc case
119− append (Node ll lx Null) r = Node ll lx r -- found the rightmost Null
121− append (Node ll lx lr) r = Node ll lx $ append lr r -- search down the right
122− -- side of the left tree
123− -- to find the rightmost
126−infixl 5 append as <>>
128−instance monoidBuilder :: Monoid Builder where
131−-- | `Builder` is not an instance of `Foldable` because `Builder` is monomorphic.
132−foldl :: forall b. (b -> ArrayBuffer -> b) -> b -> Builder -> b
134−foldl f a (Node l x r) = foldl f (f (foldl f a l) x) r
136−-- | Monomorphic foldM copied from
137−-- | [`Data.Foldable.foldM`](https://pursuit.purescript.org/packages/purescript-foldable-traversable/4.1.1/docs/Data.Foldable#v:foldM)
138−foldM :: forall b m. (Monad m) => (b -> ArrayBuffer -> m b) -> b -> Builder -> m b
139−foldM f a0 = foldl (\ma b -> ma >>= flip f b) (pure a0)
141−-- | Construct a `Builder` with a single `ArrayBuffer`. *O(1)*
142−singleton :: ArrayBuffer -> Builder
143−singleton buf = Node Null buf Null
145−-- | Add an `ArrayBuffer` to the end of the `Builder`. *O(1)*
146−snoc :: Builder -> ArrayBuffer -> Builder
147−snoc bs x = Node bs x Null
149−-- | Build a single `ArrayBuffer` from a `Builder`. *O(n)*
150−execBuilder :: forall m. (MonadEffect m) => Builder -> m ArrayBuffer
151−execBuilder bldr = do
152− let buflen = foldl (\b a -> b + AB.byteLength a) 0 bldr
153− -- Allocate the final ArrayBuffer
154− buf <- liftEffect $ AB.empty buflen
155− -- Then copy each ArrayBuffer into the final ArrayBuffer.
156− -- To memcpy from one ArrayBuffer to another, apparently we have to first view
157− -- both ArrayBuffers as ArrayView (Typed Array).
158− newview <- liftEffect (AT.whole buf :: Effect Uint8Array)
161− aview <- liftEffect (AT.whole a :: Effect Uint8Array)
162− _ <- liftEffect $ AT.setTyped newview (Just offset) aview
163− pure $ offset + AB.byteLength a
167−-- | Build an `ArrayBuffer` with do-notation in any `MonadEffect`. *O(n)*
168−execPutM :: forall m. (MonadEffect m) => PutM m Unit -> m ArrayBuffer
169−execPutM = execBuilder <=< execWriterT
88+subBuilder = lift <<< execWriterT
171−-- | Build an `ArrayBuffer` with do-notation. *O(n)*
172−execPut :: Put Unit -> Effect ArrayBuffer
175-- | Append an `ArrayBuffer` to the builder.
90-- | Append an `ArrayBuffer` to the builder.
176−putArrayBuffer :: forall m. (MonadEffect m) => ArrayBuffer -> PutM m Unit
91+putArrayBuffer :: forall m. Monad m => ArrayBuffer -> PutM m Unit
177−putArrayBuffer = tell <<< singleton
92+putArrayBuffer = tell <<< Internal.singleton <<< Internal.Buff
179−-- | Serialize an 8-bit unsigned integer (byte) into a new `ArrayBuffer`.
94+-- | Append a `DataView` to the builder.
180−encodeUint8 :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
95+putDataView :: forall m. Monad m => DataView -> PutM m Unit
181−encodeUint8 x = do
96+putDataView = tell <<< Internal.singleton <<< Internal.View
182− buf <- liftEffect $ AB.empty 1
183− _ <- liftEffect $ DV.setUint8 (DV.whole buf) 0 x
186−-- | Append an 8-bit unsigned integer (byte) to the builder.
98+-- | Append either an `ArrayBuffer` or a `DataView` to the builder.
187−putUint8 :: forall m. (MonadEffect m) => UInt -> PutM m Unit
99+putDataBuff :: forall m. Monad m => DataBuff -> PutM m Unit
188−putUint8 = putArrayBuffer <=< encodeUint8
100+putDataBuff = tell <<< Internal.singleton
190−-- | Serialize an 8-bit two’s-complement signed integer (char) into a new `ArrayBuffer`.
102+-- | Append an 8-bit unsigned integer (byte) to the builder.
191−encodeInt8 :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
103+putUint8 :: forall m. MonadEffect m => UInt -> PutM m Unit
192−encodeInt8 x = do
104+putUint8 = putArrayBuffer <=< Internal.encodeUint8
193− buf <- liftEffect $ AB.empty 1
194− _ <- liftEffect $ DV.setInt8 (DV.whole buf) 0 x
197-- | Append an 8-bit two’s-complement signed integer (char) to the builder.
106-- | Append an 8-bit two’s-complement signed integer (char) to the builder.
198−putInt8 :: forall m. (MonadEffect m) => Int -> PutM m Unit
107+putInt8 :: forall m. MonadEffect m => Int -> PutM m Unit
199−putInt8 = putArrayBuffer <=< encodeInt8
108+putInt8 = putArrayBuffer <=< Internal.encodeInt8
201−-- | Serialize a 16-bit big-endian unsigned integer into a new `ArrayBuffer`.
202−encodeUint16be :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
203−encodeUint16be x = do
204− buf <- liftEffect $ AB.empty 2
205− _ <- liftEffect $ DV.setUint16be (DV.whole buf) 0 x
208-- | Append a 16-bit big-endian unsigned integer to the builder.
110-- | Append a 16-bit big-endian unsigned integer to the builder.
209−putUint16be :: forall m. (MonadEffect m) => UInt -> PutM m Unit
111+putUint16be :: forall m. MonadEffect m => UInt -> PutM m Unit
210−putUint16be = putArrayBuffer <=< encodeUint16be
112+putUint16be = putArrayBuffer <=< Internal.encodeUint16be
212−-- | Serialize a 16-bit little-endian unsigned integer into a new `ArrayBuffer`.
213−encodeUint16le :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
214−encodeUint16le x = do
215− buf <- liftEffect $ AB.empty 2
216− _ <- liftEffect $ DV.setUint16le (DV.whole buf) 0 x
219-- | Append a 16-bit little-endian unsigned integer to the builder.
114-- | Append a 16-bit little-endian unsigned integer to the builder.
220−putUint16le :: forall m. (MonadEffect m) => UInt -> PutM m Unit
115+putUint16le :: forall m. MonadEffect m => UInt -> PutM m Unit
221−putUint16le = putArrayBuffer <=< encodeUint16le
116+putUint16le = putArrayBuffer <=< Internal.encodeUint16le
223−-- | Serialize a 16-bit big-endian two’s-complement signed integer into a new `ArrayBuffer`.
224−encodeInt16be :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
226− buf <- liftEffect $ AB.empty 2
227− _ <- liftEffect $ DV.setInt16be (DV.whole buf) 0 x
230-- | Append a 16-bit big-endian two’s-complement signed integer to the builder.
118-- | Append a 16-bit big-endian two’s-complement signed integer to the builder.
231−putInt16be :: forall m. (MonadEffect m) => Int -> PutM m Unit
119+putInt16be :: forall m. MonadEffect m => Int -> PutM m Unit
232−putInt16be = putArrayBuffer <=< encodeInt16be
120+putInt16be = putArrayBuffer <=< Internal.encodeInt16be
234−-- | Serialize a 16-bit little-endian two’s-complement signed integer into a new `ArrayBuffer`.
235−encodeInt16le :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
237− buf <- liftEffect $ AB.empty 2
238− _ <- liftEffect $ DV.setInt16le (DV.whole buf) 0 x
241-- | Append a 16-bit little-endian two’s-complement signed integer to the builder.
122-- | Append a 16-bit little-endian two’s-complement signed integer to the builder.
242−putInt16le :: forall m. (MonadEffect m) => Int -> PutM m Unit
123+putInt16le :: forall m. MonadEffect m => Int -> PutM m Unit
243−putInt16le = putArrayBuffer <=< encodeInt16le
124+putInt16le = putArrayBuffer <=< Internal.encodeInt16le
245−-- | Serialize a 32-bit big-endian unsigned integer into a new `ArrayBuffer`.
246−encodeUint32be :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
247−encodeUint32be x = do
248− buf <- liftEffect $ AB.empty 4
249− _ <- liftEffect $ DV.setUint32be (DV.whole buf) 0 x
252-- | Append a 32-bit big-endian unsigned integer to the builder.
126-- | Append a 32-bit big-endian unsigned integer to the builder.
253−putUint32be :: forall m. (MonadEffect m) => UInt -> PutM m Unit
127+putUint32be :: forall m. MonadEffect m => UInt -> PutM m Unit
254−putUint32be = putArrayBuffer <=< encodeUint32be
128+putUint32be = putArrayBuffer <=< Internal.encodeUint32be
256−-- | Serialize a 32-bit little-endian unsigned integer into a new `ArrayBuffer`.
257−encodeUint32le :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
258−encodeUint32le x = do
259− buf <- liftEffect $ AB.empty 4
260− _ <- liftEffect $ DV.setUint32le (DV.whole buf) 0 x
263-- | Append a 32-bit little-endian unsigned integer to the builder.
130-- | Append a 32-bit little-endian unsigned integer to the builder.
264−putUint32le :: forall m. (MonadEffect m) => UInt -> PutM m Unit
131+putUint32le :: forall m. MonadEffect m => UInt -> PutM m Unit
265−putUint32le = putArrayBuffer <=< encodeUint32le
132+putUint32le = putArrayBuffer <=< Internal.encodeUint32le
267−-- | Serialize a 32-bit big-endian two’s-complement signed integer into a new `ArrayBuffer`.
268−encodeInt32be :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
270− buf <- liftEffect $ AB.empty 4
271− _ <- liftEffect $ DV.setInt32be (DV.whole buf) 0 x
274-- | Append a 32-bit big-endian two’s-complement signed integer to the builder.
134-- | Append a 32-bit big-endian two’s-complement signed integer to the builder.
275−putInt32be :: forall m. (MonadEffect m) => Int -> PutM m Unit
135+putInt32be :: forall m. MonadEffect m => Int -> PutM m Unit
276−putInt32be = putArrayBuffer <=< encodeInt32be
136+putInt32be = putArrayBuffer <=< Internal.encodeInt32be
278−-- | Serialize a 32-bit little-endian two’s-complement signed integer into a new `ArrayBuffer`.
279−encodeInt32le :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
281− buf <- liftEffect $ AB.empty 4
282− _ <- liftEffect $ DV.setInt32le (DV.whole buf) 0 x
285-- | Append a 32-bit little-endian two’s-complement signed integer to the builder.
138-- | Append a 32-bit little-endian two’s-complement signed integer to the builder.
286−putInt32le :: forall m. (MonadEffect m) => Int -> PutM m Unit
139+putInt32le :: forall m. MonadEffect m => Int -> PutM m Unit
287−putInt32le = putArrayBuffer <=< encodeInt32le
140+putInt32le = putArrayBuffer <=< Internal.encodeInt32le
289−-- | Serialize a 32-bit big-endian IEEE single-precision float into a new `ArrayBuffer`.
290−encodeFloat32be :: forall m. (MonadEffect m) => Float32 -> m ArrayBuffer
291−encodeFloat32be x = do
292− buf <- liftEffect $ AB.empty 4
293− _ <- liftEffect $ DV.setFloat32be (DV.whole buf) 0 x
296-- | Append a 32-bit big-endian IEEE single-precision float to the builder.
142-- | Append a 32-bit big-endian IEEE single-precision float to the builder.
297−putFloat32be :: forall m. (MonadEffect m) => Float32 -> PutM m Unit
143+putFloat32be :: forall m. MonadEffect m => Float32 -> PutM m Unit
298−putFloat32be = putArrayBuffer <=< encodeFloat32be
144+putFloat32be = putArrayBuffer <=< Internal.encodeFloat32be
300−-- | Serialize a 32-bit little-endian IEEE single-precision float into a new `ArrayBuffer`.
301−encodeFloat32le :: forall m. (MonadEffect m) => Float32 -> m ArrayBuffer
302−encodeFloat32le x = do
303− buf <- liftEffect $ AB.empty 4
304− _ <- liftEffect $ DV.setFloat32le (DV.whole buf) 0 x
307-- | Append a 32-bit little-endian IEEE single-precision float to the builder.
146-- | Append a 32-bit little-endian IEEE single-precision float to the builder.
308−putFloat32le :: forall m. (MonadEffect m) => Float32 -> PutM m Unit
147+putFloat32le :: forall m. MonadEffect m => Float32 -> PutM m Unit
309−putFloat32le = putArrayBuffer <=< encodeFloat32le
148+putFloat32le = putArrayBuffer <=< Internal.encodeFloat32le
311−-- | Serialize a 64-bit big-endian IEEE double-precision float into a new `ArrayBuffer`.
312−encodeFloat64be :: forall m. (MonadEffect m) => Number -> m ArrayBuffer
313−encodeFloat64be x = do
314− buf <- liftEffect $ AB.empty 8
315− _ <- liftEffect $ DV.setFloat64be (DV.whole buf) 0 x
318-- | Append a 64-bit big-endian IEEE double-precision float to the builder.
150-- | Append a 64-bit big-endian IEEE double-precision float to the builder.
319−putFloat64be :: forall m. (MonadEffect m) => Number -> PutM m Unit
151+putFloat64be :: forall m. MonadEffect m => Number -> PutM m Unit
320−putFloat64be = putArrayBuffer <=< encodeFloat64be
152+putFloat64be = putArrayBuffer <=< Internal.encodeFloat64be
322−-- | Serialize a 64-bit little-endian IEEE double-precision float into a new `ArrayBuffer`.
323−encodeFloat64le :: forall m. (MonadEffect m) => Number -> m ArrayBuffer
324−encodeFloat64le x = do
325− buf <- liftEffect $ AB.empty 8
326− _ <- liftEffect $ DV.setFloat64le (DV.whole buf) 0 x
329-- | Append a 64-bit little-endian IEEE double-precision float to the builder.
154-- | Append a 64-bit little-endian IEEE double-precision float to the builder.
330−putFloat64le :: forall m. (MonadEffect m) => Number -> PutM m Unit
155+putFloat64le :: forall m. MonadEffect m => Number -> PutM m Unit
331−putFloat64le = putArrayBuffer <=< encodeFloat64le
156+putFloat64le = putArrayBuffer <=< Internal.encodeFloat64le
334−-- ## Implementation Details
336−-- We want our `Builder` to be a data structure with
337−-- * *O(1)* monoid append
340−-- Our `Builder` implementation is an unbalanced binary tree.
342−-- For monoid `append`, what we actually get is *O(1)* when either the
343−-- left or right tree is a singleton. If that's not true, then in the
344−-- unlikely worst case `append` might be *O(n)*.
346−-- `Builder` is optimized what we consider to be normal usage, that is,
347−-- `snoc`ing singleton elements to the end of the `Builder`.
349−-- If a Builder is built entirely by `snoc`ing, it will look like a
350−-- left-only binary tree, a.k.a. a linked list.
362−-- If two of these `snoc`-built trees are `append`ed, then the new tree
377−-- This is all similar to
378−-- [__bytestring-tree-builder__](https://hackage.haskell.org/package/bytestring-tree-builder)
380−-- [`Tree`](https://hackage.haskell.org/package/bytestring-tree-builder-0.2.7.3/docs/src/ByteString.TreeBuilder.Tree.html#Tree)
381−-- structure in __bytestring-tree-builder__ only carries values in its
382−-- leaves, which is how it achieves *O(1)* appending, at the cost of
383−-- a higher coefficient time factor on the fold.
385−-- We hope that this implementation is fairly fast, but we
386−-- haven't chosen this implementation because it's fast, we've chosen
387−-- this implementation because it's simple.
388−-- If someone wants to create a fast Purescript ArrayBuffer serialization
389−-- library, then they can benchmark against this one to prove that the new
392−-- One relatively cheap and simple performance improvement for this library would be to
393−-- remove the Null constructor of `Builder` and instead use Javascript nulls.
395−-- In the longer term, it might make sense to try to change the Builder so
396−-- that it works like the
397−-- https://hackage.haskell.org/package/bytestring/docs/Data-ByteString-Builder.html
399−-- Here are some benchmarks of different Haskell ByteString builders
400−-- https://github.com/haskell-perf/strict-bytestring-builders
402−-- We've tried to design the API for this library with minimal assumptions,
403−-- so that if we want to change the Builder implementation later then we can.
405−-- Another way this could go:
406−-- https://kodimensional.dev/posts/2019-03-25-comonadic-builders