@@ -5,403 +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 `WriterT Builder` transformer monad which
50-- | The `PutM` monad is a `WriterT Builder` transformer monad which
68-- | gives us do-notation for the `Builder` monoid. The base monad must be
51-- | gives us do-notation for the `Builder` monoid. The base monad must be
69-- | a `MonadEffect`.
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−-- | The `Put` monad is a `WriterT Builder Effect` monad which
58+-- | The `PutM` type reified to `Effect`, in other words `WriterT Builder Effect`.
73−-- | gives us do-notation for the `Builder` monoid.
74type Put = PutM Effect
59type Put = PutM Effect
76−-- | Monoidal builder for `ArrayBuffer`s.
61+-- | Build an `ArrayBuffer` with do-notation in any `MonadEffect`. *O(n)* Stack-safe.
77−-- |
62+execPutM :: forall m. MonadEffect m => MonadRec m => PutM m Unit -> m ArrayBuffer
78−-- | ### 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.
80−-- | __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
81−-- | 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.
83−-- | The `Builder` monoid in this library is efficient when we `snoc` single
76+-- | In a `PutM` monad do-block, we can
84−-- | items onto the end of it, or when we only `cons` single items to the
85−-- | beginning, but it can be less efficient when we are mixing `cons` and
87−-- | This matters when we're appending three or more `Builder`s
88−-- | in one associative expression, because the
89−-- | `Semigroup` append operator `<>` is right-associative.
91−-- | To solve this, we provide an operator `<>>` for appending `Builders`.
92−-- | `<>>` is exactly the same as `<>`, but left-associative.
93−-- | This only matters when we're chaining together three
94−-- | or more `Builder`s in a single associative expression.
97−-- | builder₁ <> builder₂ <> builder₃
99−-- | we should always prefer to
102−-- | builder₁ <>> builder₂ <>> builder₃
79+-- | do
103−-- | ```
80+-- | messageBuilder <- subBuilder $ do
104−-- | so that we get the efficient
81+-- | putField1
105−-- | `snoc`ing of `Builder`s.
106−-- |
82+-- | putField2
107−-- | If we build our `ArrayBuffer`s with the `PutM` monad instead of appending by
108−-- | using the `Semigroup` instance of `Builder`, then we always get the efficient
111−data Builder
84+-- | putInt32be $ length messageBuilder
112− = Node Builder ArrayBuffer Builder
85+-- | tell messageBuilder
114−
87+subBuilder :: forall m. Monad m => PutM m Unit -> PutM m Builder
115−instance semigroupBuilder :: Semigroup Builder where
116− append Null Null = Null
119− append l (Node Null rx rr) = Node l rx rr -- this is the snoc case
120− append (Node ll lx Null) r = Node ll lx r -- found the rightmost Null
122− append (Node ll lx lr) r = Node ll lx $ append lr r -- search down the right
123− -- side of the left tree
124− -- to find the rightmost
127−infixl 5 append as <>>
129−instance monoidBuilder :: Monoid Builder where
132−-- | `Builder` is not an instance of `Foldable` because `Builder` is monomorphic.
133−foldl :: forall b. (b -> ArrayBuffer -> b) -> b -> Builder -> b
135−foldl f a (Node l x r) = foldl f (f (foldl f a l) x) r
137−-- | Monomorphic foldM copied from
138−-- | [`Data.Foldable.foldM`](https://pursuit.purescript.org/packages/purescript-foldable-traversable/4.1.1/docs/Data.Foldable#v:foldM)
139−foldM :: forall b m. (Monad m) => (b -> ArrayBuffer -> m b) -> b -> Builder -> m b
140−foldM f a0 = foldl (\ma b -> ma >>= flip f b) (pure a0)
142−-- | Construct a `Builder` with a single `ArrayBuffer`. *O(1)*
143−singleton :: ArrayBuffer -> Builder
144−singleton buf = Node Null buf Null
146−-- | Add an `ArrayBuffer` to the end of the `Builder`. *O(1)*
147−snoc :: Builder -> ArrayBuffer -> Builder
148−snoc bs x = Node bs x Null
150−-- | Build a single `ArrayBuffer` from a `Builder`. *O(n)*
151−execBuilder :: forall m. (MonadEffect m) => Builder -> m ArrayBuffer
152−execBuilder bldr = do
153− let buflen = foldl (\b a -> b + AB.byteLength a) 0 bldr
154− -- Allocate the final ArrayBuffer
155− buf <- liftEffect $ AB.empty buflen
156− -- Then copy each ArrayBuffer into the final ArrayBuffer.
157− -- To memcpy from one ArrayBuffer to another, apparently we have to first view
158− -- both ArrayBuffers as ArrayView (Typed Array).
159− newview <- liftEffect (AT.whole buf :: Effect Uint8Array)
162− aview <- liftEffect (AT.whole a :: Effect Uint8Array)
163− _ <- liftEffect $ AT.setTyped newview (Just offset) aview
164− pure $ offset + AB.byteLength a
168−-- | Build an `ArrayBuffer` with do-notation in any `MonadEffect`. *O(n)*
169−execPutM :: forall m. (MonadEffect m) => PutM m Unit -> m ArrayBuffer
170−execPutM = execBuilder <=< execWriterT
88+subBuilder = lift <<< execWriterT
172−-- | Build an `ArrayBuffer` with do-notation. *O(n)*
173−execPut :: Put Unit -> Effect ArrayBuffer
176-- | Append an `ArrayBuffer` to the builder.
90-- | Append an `ArrayBuffer` to the builder.
177−putArrayBuffer :: forall m. (MonadEffect m) => ArrayBuffer -> PutM m Unit
91+putArrayBuffer :: forall m. Monad m => ArrayBuffer -> PutM m Unit
178−putArrayBuffer = tell <<< singleton
92+putArrayBuffer = tell <<< Internal.singleton <<< Internal.Buff
180−-- | Serialize an 8-bit unsigned integer (byte) into a new `ArrayBuffer`.
94+-- | Append a `DataView` to the builder.
181−encodeUint8 :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
95+putDataView :: forall m. Monad m => DataView -> PutM m Unit
182−encodeUint8 x = do
96+putDataView = tell <<< Internal.singleton <<< Internal.View
183− buf <- liftEffect $ AB.empty 1
184− _ <- liftEffect $ DV.setUint8 (DV.whole buf) 0 x
187−-- | Append an 8-bit unsigned integer (byte) to the builder.
98+-- | Append either an `ArrayBuffer` or a `DataView` to the builder.
188−putUint8 :: forall m. (MonadEffect m) => UInt -> PutM m Unit
99+putDataBuff :: forall m. Monad m => DataBuff -> PutM m Unit
189−putUint8 = putArrayBuffer <=< encodeUint8
100+putDataBuff = tell <<< Internal.singleton
191−-- | 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.
192−encodeInt8 :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
103+putUint8 :: forall m. MonadEffect m => UInt -> PutM m Unit
193−encodeInt8 x = do
104+putUint8 = putArrayBuffer <=< Internal.encodeUint8
194− buf <- liftEffect $ AB.empty 1
195− _ <- liftEffect $ DV.setInt8 (DV.whole buf) 0 x
198-- | 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.
199−putInt8 :: forall m. (MonadEffect m) => Int -> PutM m Unit
107+putInt8 :: forall m. MonadEffect m => Int -> PutM m Unit
200−putInt8 = putArrayBuffer <=< encodeInt8
108+putInt8 = putArrayBuffer <=< Internal.encodeInt8
202−-- | Serialize a 16-bit big-endian unsigned integer into a new `ArrayBuffer`.
203−encodeUint16be :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
204−encodeUint16be x = do
205− buf <- liftEffect $ AB.empty 2
206− _ <- liftEffect $ DV.setUint16be (DV.whole buf) 0 x
209-- | Append a 16-bit big-endian unsigned integer to the builder.
110-- | Append a 16-bit big-endian unsigned integer to the builder.
210−putUint16be :: forall m. (MonadEffect m) => UInt -> PutM m Unit
111+putUint16be :: forall m. MonadEffect m => UInt -> PutM m Unit
211−putUint16be = putArrayBuffer <=< encodeUint16be
112+putUint16be = putArrayBuffer <=< Internal.encodeUint16be
213−-- | Serialize a 16-bit little-endian unsigned integer into a new `ArrayBuffer`.
214−encodeUint16le :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
215−encodeUint16le x = do
216− buf <- liftEffect $ AB.empty 2
217− _ <- liftEffect $ DV.setUint16le (DV.whole buf) 0 x
220-- | Append a 16-bit little-endian unsigned integer to the builder.
114-- | Append a 16-bit little-endian unsigned integer to the builder.
221−putUint16le :: forall m. (MonadEffect m) => UInt -> PutM m Unit
115+putUint16le :: forall m. MonadEffect m => UInt -> PutM m Unit
222−putUint16le = putArrayBuffer <=< encodeUint16le
116+putUint16le = putArrayBuffer <=< Internal.encodeUint16le
224−-- | Serialize a 16-bit big-endian two’s-complement signed integer into a new `ArrayBuffer`.
225−encodeInt16be :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
227− buf <- liftEffect $ AB.empty 2
228− _ <- liftEffect $ DV.setInt16be (DV.whole buf) 0 x
231-- | 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.
232−putInt16be :: forall m. (MonadEffect m) => Int -> PutM m Unit
119+putInt16be :: forall m. MonadEffect m => Int -> PutM m Unit
233−putInt16be = putArrayBuffer <=< encodeInt16be
120+putInt16be = putArrayBuffer <=< Internal.encodeInt16be
235−-- | Serialize a 16-bit little-endian two’s-complement signed integer into a new `ArrayBuffer`.
236−encodeInt16le :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
238− buf <- liftEffect $ AB.empty 2
239− _ <- liftEffect $ DV.setInt16le (DV.whole buf) 0 x
242-- | 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.
243−putInt16le :: forall m. (MonadEffect m) => Int -> PutM m Unit
123+putInt16le :: forall m. MonadEffect m => Int -> PutM m Unit
244−putInt16le = putArrayBuffer <=< encodeInt16le
124+putInt16le = putArrayBuffer <=< Internal.encodeInt16le
246−-- | Serialize a 32-bit big-endian unsigned integer into a new `ArrayBuffer`.
247−encodeUint32be :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
248−encodeUint32be x = do
249− buf <- liftEffect $ AB.empty 4
250− _ <- liftEffect $ DV.setUint32be (DV.whole buf) 0 x
253-- | Append a 32-bit big-endian unsigned integer to the builder.
126-- | Append a 32-bit big-endian unsigned integer to the builder.
254−putUint32be :: forall m. (MonadEffect m) => UInt -> PutM m Unit
127+putUint32be :: forall m. MonadEffect m => UInt -> PutM m Unit
255−putUint32be = putArrayBuffer <=< encodeUint32be
128+putUint32be = putArrayBuffer <=< Internal.encodeUint32be
257−-- | Serialize a 32-bit little-endian unsigned integer into a new `ArrayBuffer`.
258−encodeUint32le :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
259−encodeUint32le x = do
260− buf <- liftEffect $ AB.empty 4
261− _ <- liftEffect $ DV.setUint32le (DV.whole buf) 0 x
264-- | Append a 32-bit little-endian unsigned integer to the builder.
130-- | Append a 32-bit little-endian unsigned integer to the builder.
265−putUint32le :: forall m. (MonadEffect m) => UInt -> PutM m Unit
131+putUint32le :: forall m. MonadEffect m => UInt -> PutM m Unit
266−putUint32le = putArrayBuffer <=< encodeUint32le
132+putUint32le = putArrayBuffer <=< Internal.encodeUint32le
268−-- | Serialize a 32-bit big-endian two’s-complement signed integer into a new `ArrayBuffer`.
269−encodeInt32be :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
271− buf <- liftEffect $ AB.empty 4
272− _ <- liftEffect $ DV.setInt32be (DV.whole buf) 0 x
275-- | 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.
276−putInt32be :: forall m. (MonadEffect m) => Int -> PutM m Unit
135+putInt32be :: forall m. MonadEffect m => Int -> PutM m Unit
277−putInt32be = putArrayBuffer <=< encodeInt32be
136+putInt32be = putArrayBuffer <=< Internal.encodeInt32be
279−-- | Serialize a 32-bit little-endian two’s-complement signed integer into a new `ArrayBuffer`.
280−encodeInt32le :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
282− buf <- liftEffect $ AB.empty 4
283− _ <- liftEffect $ DV.setInt32le (DV.whole buf) 0 x
286-- | 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.
287−putInt32le :: forall m. (MonadEffect m) => Int -> PutM m Unit
139+putInt32le :: forall m. MonadEffect m => Int -> PutM m Unit
288−putInt32le = putArrayBuffer <=< encodeInt32le
140+putInt32le = putArrayBuffer <=< Internal.encodeInt32le
290−-- | Serialize a 32-bit big-endian IEEE single-precision float into a new `ArrayBuffer`.
291−encodeFloat32be :: forall m. (MonadEffect m) => Float32 -> m ArrayBuffer
292−encodeFloat32be x = do
293− buf <- liftEffect $ AB.empty 4
294− _ <- liftEffect $ DV.setFloat32be (DV.whole buf) 0 x
297-- | 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.
298−putFloat32be :: forall m. (MonadEffect m) => Float32 -> PutM m Unit
143+putFloat32be :: forall m. MonadEffect m => Float32 -> PutM m Unit
299−putFloat32be = putArrayBuffer <=< encodeFloat32be
144+putFloat32be = putArrayBuffer <=< Internal.encodeFloat32be
301−-- | Serialize a 32-bit little-endian IEEE single-precision float into a new `ArrayBuffer`.
302−encodeFloat32le :: forall m. (MonadEffect m) => Float32 -> m ArrayBuffer
303−encodeFloat32le x = do
304− buf <- liftEffect $ AB.empty 4
305− _ <- liftEffect $ DV.setFloat32le (DV.whole buf) 0 x
308-- | 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.
309−putFloat32le :: forall m. (MonadEffect m) => Float32 -> PutM m Unit
147+putFloat32le :: forall m. MonadEffect m => Float32 -> PutM m Unit
310−putFloat32le = putArrayBuffer <=< encodeFloat32le
148+putFloat32le = putArrayBuffer <=< Internal.encodeFloat32le
312−-- | Serialize a 64-bit big-endian IEEE double-precision float into a new `ArrayBuffer`.
313−encodeFloat64be :: forall m. (MonadEffect m) => Number -> m ArrayBuffer
314−encodeFloat64be x = do
315− buf <- liftEffect $ AB.empty 8
316− _ <- liftEffect $ DV.setFloat64be (DV.whole buf) 0 x
319-- | 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.
320−putFloat64be :: forall m. (MonadEffect m) => Number -> PutM m Unit
151+putFloat64be :: forall m. MonadEffect m => Number -> PutM m Unit
321−putFloat64be = putArrayBuffer <=< encodeFloat64be
152+putFloat64be = putArrayBuffer <=< Internal.encodeFloat64be
323−-- | Serialize a 64-bit little-endian IEEE double-precision float into a new `ArrayBuffer`.
324−encodeFloat64le :: forall m. (MonadEffect m) => Number -> m ArrayBuffer
325−encodeFloat64le x = do
326− buf <- liftEffect $ AB.empty 8
327− _ <- liftEffect $ DV.setFloat64le (DV.whole buf) 0 x
330-- | 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.
331−putFloat64le :: forall m. (MonadEffect m) => Number -> PutM m Unit
155+putFloat64le :: forall m. MonadEffect m => Number -> PutM m Unit
332−putFloat64le = putArrayBuffer <=< encodeFloat64le
156+putFloat64le = putArrayBuffer <=< Internal.encodeFloat64le
335−-- ## Implementation Details
337−-- We want our `Builder` to be a data structure with
338−-- * *O(1)* monoid append
341−-- Our `Builder` implementation is an unbalanced binary tree.
343−-- For monoid `append`, what we actually get is *O(1)* when either the
344−-- left or right tree is a singleton. If that's not true, then in the
345−-- unlikely worst case `append` might be *O(n)*.
347−-- `Builder` is optimized what we consider to be normal usage, that is,
348−-- `snoc`ing singleton elements to the end of the `Builder`.
350−-- If a Builder is built entirely by `snoc`ing, it will look like a
351−-- left-only binary tree, a.k.a. a linked list.
363−-- If two of these `snoc`-built trees are `append`ed, then the new tree
378−-- This is all similar to
379−-- [__bytestring-tree-builder__](https://hackage.haskell.org/package/bytestring-tree-builder)
381−-- [`Tree`](https://hackage.haskell.org/package/bytestring-tree-builder-0.2.7.3/docs/src/ByteString.TreeBuilder.Tree.html#Tree)
382−-- structure in __bytestring-tree-builder__ only carries values in its
383−-- leaves, which is how it achieves *O(1)* appending, at the cost of
384−-- a higher coefficient time factor on the fold.
386−-- We hope that this implementation is fairly fast, but we
387−-- haven't chosen this implementation because it's fast, we've chosen
388−-- this implementation because it's simple.
389−-- If someone wants to create a fast Purescript ArrayBuffer serialization
390−-- library, then they can benchmark against this one to prove that the new
393−-- One relatively cheap and simple performance improvement for this library would be to
394−-- remove the Null constructor of `Builder` and instead use Javascript nulls.
396−-- In the longer term, it might make sense to try to change the Builder so
397−-- that it works like the
398−-- https://hackage.haskell.org/package/bytestring/docs/Data-ByteString-Builder.html
400−-- Here are some benchmarks of different Haskell ByteString builders
401−-- https://github.com/haskell-perf/strict-bytestring-builders
403−-- We've tried to design the API for this library with minimal assumptions,
404−-- so that if we want to change the Builder implementation later then we can.
406−-- Another way this could go:
407−-- https://kodimensional.dev/posts/2019-03-25-comonadic-builders