@@ -4,395 +4,153 @@
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 other operations for working with `ArrayBuffer`, see
10+-- | [`Data.ArrayBuffer.ArrayBuffer`](https://pursuit.purescript.org/packages/purescript-arraybuffer/docs/Data.ArrayBuffer.ArrayBuffer)
11+-- | in package __arraybuffer__.
7module Data.ArrayBuffer.Builder
12module Data.ArrayBuffer.Builder
10−, execPutM
15+ , execPutM
11−, execPut
16+ , execPut
12−, putArrayBuffer
18+ , putArrayBuffer
13−, putUint8
21+ , putUint8
14−, putInt8
22+ , putInt8
15−, putUint16be
23+ , putUint16be
16−, putUint16le
24+ , putUint16le
17−, putInt16be
25+ , putInt16be
18−, putInt16le
26+ , putInt16le
19−, putUint32be
27+ , putUint32be
20−, putUint32le
28+ , putUint32le
21−, putInt32be
29+ , putInt32be
22−, putInt32le
30+ , putInt32le
23−, putFloat32be
31+ , putFloat32be
24−, putFloat32le
32+ , putFloat32le
25−, putFloat64be
33+ , putFloat64be
26−, putFloat64le
34+ , putFloat64le
27−, Builder
35+ , module Data.ArrayBuffer.Builder.Internal
49import Prelude
38import Prelude
40+import Control.Monad.Rec.Class (class MonadRec)
51−import Control.Monad.Writer.Trans (WriterT, execWriterT, tell)
41+import Control.Monad.Writer.Trans (WriterT, execWriterT, tell, lift)
52−import Data.ArrayBuffer.ArrayBuffer as AB
42+import Data.ArrayBuffer.Builder.Internal (Builder, DataBuff(..), length, toView, (<>>))
53−import Data.ArrayBuffer.DataView as DV
54−import Data.ArrayBuffer.Typed as AT
43+import Data.ArrayBuffer.Builder.Internal as Internal
55−import Data.ArrayBuffer.Types (ArrayBuffer, Uint8Array)
44+import Data.ArrayBuffer.Types (ArrayBuffer, DataView)
56import Data.Float32 (Float32)
45import Data.Float32 (Float32)
57−import Data.Maybe (Maybe(..))
58import Data.UInt (UInt)
46import Data.UInt (UInt)
59import Effect (Effect)
47import Effect (Effect)
60−import Effect.Class (class MonadEffect, liftEffect)
48+import Effect.Class (class MonadEffect)
62−-- | The `PutM` monad is a Writer transformer monad which
50+-- | The `PutM` monad is a `WriterT Builder` transformer monad which
63−-- | [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
64−-- | 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.
65type PutM = WriterT Builder
56type PutM = WriterT Builder
67−-- | `Put` monad is the non-transformer version of `PutM`.
58+-- | The `PutM` type reified to `Effect`, in other words `WriterT Builder Effect`.
68type Put = PutM Effect
59type Put = PutM Effect
70−-- | Monoidal builder for `ArrayBuffer`s.
61+-- | Build an `ArrayBuffer` with do-notation in any `MonadEffect`. *O(n)* Stack-safe.
71−-- |
62+execPutM :: forall m. MonadEffect m => MonadRec m => PutM m Unit -> m ArrayBuffer
72−-- | ### 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.
74−-- | __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
75−-- | 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.
77−-- | The `Builder` monoid in this library is efficient when we `snoc` single
76+-- | In a `PutM` monad do-block, we can
78−-- | items onto the end of it, or when we only `cons` single items to the
79−-- | beginning, but it can be less efficient when we are mixing `cons` and
81−-- | This matters when we're appending three or more `Builder`s
82−-- | in one associative expression, because the
83−-- | `Semigroup` append operator `<>` is right-associative.
85−-- | To solve this, we provide an operator `<>>` for appending `Builders`.
86−-- | `<>>` is exactly the same as `<>`, but left-associative.
87−-- | This only matters when we're chaining together three
88−-- | or more `Builder`s in a single associative expression.
91−-- | builder₁ <> builder₂ <> builder₃
93−-- | we should always prefer to
96−-- | builder₁ <>> builder₂ <>> builder₃
98−-- | so that we get the efficient
79+-- | do
99−-- | `snoc`ing of `Builder`s.
80+-- | messageBuilder <- subBuilder $ do
101−-- | If we build our `ArrayBuffer`s with the `PutM` monad instead of appending by
84+-- | putInt32be $ length messageBuilder
102−-- | using the `Semigroup` instance of `Builder`, then we always get the efficient
85+-- | tell messageBuilder
103−-- | `snoc` case.
86+-- | ```
104−-- |
87+subBuilder :: forall m. Monad m => PutM m Unit -> PutM m Builder
106− = Node Builder ArrayBuffer Builder
109−instance semigroupBuilder :: Semigroup Builder where
110− append Null Null = Null
113− append l (Node Null rx rr) = Node l rx rr -- this is the snoc case
114− append (Node ll lx Null) r = Node ll lx r -- found the rightmost Null
116− append (Node ll lx lr) r = Node ll lx $ append lr r -- search down the right
117− -- side of the left tree
118− -- to find the rightmost
121−infixl 5 append as <>>
123−instance monoidBuilder :: Monoid Builder where
126−-- | `Builder` is not an instance of `Foldable` because `Builder` is monomorphic.
127−foldl :: forall b. (b -> ArrayBuffer -> b) -> b -> Builder -> b
129−foldl f a (Node l x r) = foldl f (f (foldl f a l) x) r
131−-- | Monomorphic foldM copied from
132−-- | [`Data.Foldable.foldM`](https://pursuit.purescript.org/packages/purescript-foldable-traversable/4.1.1/docs/Data.Foldable#v:foldM)
133−foldM :: forall b m. (Monad m) => (b -> ArrayBuffer -> m b) -> b -> Builder -> m b
134−foldM f a0 = foldl (\ma b -> ma >>= flip f b) (pure a0)
136−-- | Construct a `Builder` with a single `ArrayBuffer`. *O(1)*
137−singleton :: ArrayBuffer -> Builder
138−singleton buf = Node Null buf Null
140−-- | Add an `ArrayBuffer` to the end of the `Builder`. *O(1)*
141−snoc :: Builder -> ArrayBuffer -> Builder
142−snoc bs x = Node bs x Null
144−-- | Build a single `ArrayBuffer` from a `Builder`. *O(n)*
145−execBuilder :: forall m. (MonadEffect m) => Builder -> m ArrayBuffer
146−execBuilder bldr = do
147− let buflen = foldl (\b a -> b + AB.byteLength a) 0 bldr
148− -- Allocate the final ArrayBuffer
149− buf <- liftEffect $ AB.empty buflen
150− -- Then copy each ArrayBuffer into the final ArrayBuffer.
151− -- To memcpy from one ArrayBuffer to another, apparently we have to first view
152− -- both ArrayBuffers as ArrayView (Typed Array).
153− newview <- liftEffect (AT.whole buf :: Effect Uint8Array)
156− aview <- liftEffect (AT.whole a :: Effect Uint8Array)
157− _ <- liftEffect $ AT.setTyped newview (Just offset) aview
158− pure $ offset + AB.byteLength a
162−-- | Build an `ArrayBuffer` with do-notation in any `MonadEffect`. *O(n)*
163−execPutM :: forall m. (MonadEffect m) => PutM m Unit -> m ArrayBuffer
164−execPutM = execBuilder <=< execWriterT
88+subBuilder = lift <<< execWriterT
166−-- | Build an `ArrayBuffer` with do-notation. *O(n)*
167−execPut :: Put Unit -> Effect ArrayBuffer
170-- | Append an `ArrayBuffer` to the builder.
90-- | Append an `ArrayBuffer` to the builder.
171−putArrayBuffer :: forall m. (MonadEffect m) => ArrayBuffer -> PutM m Unit
91+putArrayBuffer :: forall m. Monad m => ArrayBuffer -> PutM m Unit
172−putArrayBuffer = tell <<< singleton
92+putArrayBuffer = tell <<< Internal.singleton <<< Internal.Buff
174−-- | Serialize an 8-bit unsigned integer (byte) into a new `ArrayBuffer`.
94+-- | Append a `DataView` to the builder.
175−encodeUint8 :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
95+putDataView :: forall m. Monad m => DataView -> PutM m Unit
176−encodeUint8 x = do
96+putDataView = tell <<< Internal.singleton <<< Internal.View
177− buf <- liftEffect $ AB.empty 1
178− _ <- liftEffect $ DV.setUint8 (DV.whole buf) 0 x
181−-- | Append an 8-bit unsigned integer (byte) to the builder.
98+-- | Append either an `ArrayBuffer` or a `DataView` to the builder.
182−putUint8 :: forall m. (MonadEffect m) => UInt -> PutM m Unit
99+putDataBuff :: forall m. Monad m => DataBuff -> PutM m Unit
183−putUint8 = putArrayBuffer <=< encodeUint8
100+putDataBuff = tell <<< Internal.singleton
185−-- | 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.
186−encodeInt8 :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
103+putUint8 :: forall m. MonadEffect m => UInt -> PutM m Unit
187−encodeInt8 x = do
104+putUint8 = putArrayBuffer <=< Internal.encodeUint8
188− buf <- liftEffect $ AB.empty 1
189− _ <- liftEffect $ DV.setInt8 (DV.whole buf) 0 x
192-- | 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.
193−putInt8 :: forall m. (MonadEffect m) => Int -> PutM m Unit
107+putInt8 :: forall m. MonadEffect m => Int -> PutM m Unit
194−putInt8 = putArrayBuffer <=< encodeInt8
108+putInt8 = putArrayBuffer <=< Internal.encodeInt8
196−-- | Serialize a 16-bit big-endian unsigned integer into a new `ArrayBuffer`.
197−encodeUint16be :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
198−encodeUint16be x = do
199− buf <- liftEffect $ AB.empty 2
200− _ <- liftEffect $ DV.setUint16be (DV.whole buf) 0 x
203-- | Append a 16-bit big-endian unsigned integer to the builder.
110-- | Append a 16-bit big-endian unsigned integer to the builder.
204−putUint16be :: forall m. (MonadEffect m) => UInt -> PutM m Unit
111+putUint16be :: forall m. MonadEffect m => UInt -> PutM m Unit
205−putUint16be = putArrayBuffer <=< encodeUint16be
112+putUint16be = putArrayBuffer <=< Internal.encodeUint16be
207−-- | Serialize a 16-bit little-endian unsigned integer into a new `ArrayBuffer`.
208−encodeUint16le :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
209−encodeUint16le x = do
210− buf <- liftEffect $ AB.empty 2
211− _ <- liftEffect $ DV.setUint16le (DV.whole buf) 0 x
214-- | Append a 16-bit little-endian unsigned integer to the builder.
114-- | Append a 16-bit little-endian unsigned integer to the builder.
215−putUint16le :: forall m. (MonadEffect m) => UInt -> PutM m Unit
115+putUint16le :: forall m. MonadEffect m => UInt -> PutM m Unit
216−putUint16le = putArrayBuffer <=< encodeUint16le
116+putUint16le = putArrayBuffer <=< Internal.encodeUint16le
218−-- | Serialize a 16-bit big-endian two’s-complement signed integer into a new `ArrayBuffer`.
219−encodeInt16be :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
221− buf <- liftEffect $ AB.empty 2
222− _ <- liftEffect $ DV.setInt16be (DV.whole buf) 0 x
225-- | 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.
226−putInt16be :: forall m. (MonadEffect m) => Int -> PutM m Unit
119+putInt16be :: forall m. MonadEffect m => Int -> PutM m Unit
227−putInt16be = putArrayBuffer <=< encodeInt16be
120+putInt16be = putArrayBuffer <=< Internal.encodeInt16be
229−-- | Serialize a 16-bit little-endian two’s-complement signed integer into a new `ArrayBuffer`.
230−encodeInt16le :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
232− buf <- liftEffect $ AB.empty 2
233− _ <- liftEffect $ DV.setInt16le (DV.whole buf) 0 x
236-- | 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.
237−putInt16le :: forall m. (MonadEffect m) => Int -> PutM m Unit
123+putInt16le :: forall m. MonadEffect m => Int -> PutM m Unit
238−putInt16le = putArrayBuffer <=< encodeInt16le
124+putInt16le = putArrayBuffer <=< Internal.encodeInt16le
240−-- | Serialize a 32-bit big-endian unsigned integer into a new `ArrayBuffer`.
241−encodeUint32be :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
242−encodeUint32be x = do
243− buf <- liftEffect $ AB.empty 4
244− _ <- liftEffect $ DV.setUint32be (DV.whole buf) 0 x
247-- | Append a 32-bit big-endian unsigned integer to the builder.
126-- | Append a 32-bit big-endian unsigned integer to the builder.
248−putUint32be :: forall m. (MonadEffect m) => UInt -> PutM m Unit
127+putUint32be :: forall m. MonadEffect m => UInt -> PutM m Unit
249−putUint32be = putArrayBuffer <=< encodeUint32be
128+putUint32be = putArrayBuffer <=< Internal.encodeUint32be
251−-- | Serialize a 32-bit little-endian unsigned integer into a new `ArrayBuffer`.
252−encodeUint32le :: forall m. (MonadEffect m) => UInt -> m ArrayBuffer
253−encodeUint32le x = do
254− buf <- liftEffect $ AB.empty 4
255− _ <- liftEffect $ DV.setUint32le (DV.whole buf) 0 x
258-- | Append a 32-bit little-endian unsigned integer to the builder.
130-- | Append a 32-bit little-endian unsigned integer to the builder.
259−putUint32le :: forall m. (MonadEffect m) => UInt -> PutM m Unit
131+putUint32le :: forall m. MonadEffect m => UInt -> PutM m Unit
260−putUint32le = putArrayBuffer <=< encodeUint32le
132+putUint32le = putArrayBuffer <=< Internal.encodeUint32le
262−-- | Serialize a 32-bit big-endian two’s-complement signed integer into a new `ArrayBuffer`.
263−encodeInt32be :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
265− buf <- liftEffect $ AB.empty 4
266− _ <- liftEffect $ DV.setInt32be (DV.whole buf) 0 x
269-- | 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.
270−putInt32be :: forall m. (MonadEffect m) => Int -> PutM m Unit
135+putInt32be :: forall m. MonadEffect m => Int -> PutM m Unit
271−putInt32be = putArrayBuffer <=< encodeInt32be
136+putInt32be = putArrayBuffer <=< Internal.encodeInt32be
273−-- | Serialize a 32-bit little-endian two’s-complement signed integer into a new `ArrayBuffer`.
274−encodeInt32le :: forall m. (MonadEffect m) => Int -> m ArrayBuffer
276− buf <- liftEffect $ AB.empty 4
277− _ <- liftEffect $ DV.setInt32le (DV.whole buf) 0 x
280-- | 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.
281−putInt32le :: forall m. (MonadEffect m) => Int -> PutM m Unit
139+putInt32le :: forall m. MonadEffect m => Int -> PutM m Unit
282−putInt32le = putArrayBuffer <=< encodeInt32le
140+putInt32le = putArrayBuffer <=< Internal.encodeInt32le
284−-- | Serialize a 32-bit big-endian IEEE single-precision float into a new `ArrayBuffer`.
285−encodeFloat32be :: forall m. (MonadEffect m) => Float32 -> m ArrayBuffer
286−encodeFloat32be x = do
287− buf <- liftEffect $ AB.empty 4
288− _ <- liftEffect $ DV.setFloat32be (DV.whole buf) 0 x
291-- | 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.
292−putFloat32be :: forall m. (MonadEffect m) => Float32 -> PutM m Unit
143+putFloat32be :: forall m. MonadEffect m => Float32 -> PutM m Unit
293−putFloat32be = putArrayBuffer <=< encodeFloat32be
144+putFloat32be = putArrayBuffer <=< Internal.encodeFloat32be
295−-- | Serialize a 32-bit little-endian IEEE single-precision float into a new `ArrayBuffer`.
296−encodeFloat32le :: forall m. (MonadEffect m) => Float32 -> m ArrayBuffer
297−encodeFloat32le x = do
298− buf <- liftEffect $ AB.empty 4
299− _ <- liftEffect $ DV.setFloat32le (DV.whole buf) 0 x
302-- | 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.
303−putFloat32le :: forall m. (MonadEffect m) => Float32 -> PutM m Unit
147+putFloat32le :: forall m. MonadEffect m => Float32 -> PutM m Unit
304−putFloat32le = putArrayBuffer <=< encodeFloat32le
148+putFloat32le = putArrayBuffer <=< Internal.encodeFloat32le
306−-- | Serialize a 64-bit big-endian IEEE double-precision float into a new `ArrayBuffer`.
307−encodeFloat64be :: forall m. (MonadEffect m) => Number -> m ArrayBuffer
308−encodeFloat64be x = do
309− buf <- liftEffect $ AB.empty 8
310− _ <- liftEffect $ DV.setFloat64be (DV.whole buf) 0 x
313-- | 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.
314−putFloat64be :: forall m. (MonadEffect m) => Number -> PutM m Unit
151+putFloat64be :: forall m. MonadEffect m => Number -> PutM m Unit
315−putFloat64be = putArrayBuffer <=< encodeFloat64be
152+putFloat64be = putArrayBuffer <=< Internal.encodeFloat64be
317−-- | Serialize a 64-bit little-endian IEEE double-precision float into a new `ArrayBuffer`.
318−encodeFloat64le :: forall m. (MonadEffect m) => Number -> m ArrayBuffer
319−encodeFloat64le x = do
320− buf <- liftEffect $ AB.empty 8
321− _ <- liftEffect $ DV.setFloat64le (DV.whole buf) 0 x
324-- | 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.
325−putFloat64le :: forall m. (MonadEffect m) => Number -> PutM m Unit
155+putFloat64le :: forall m. MonadEffect m => Number -> PutM m Unit
326−putFloat64le = putArrayBuffer <=< encodeFloat64le
156+putFloat64le = putArrayBuffer <=< Internal.encodeFloat64le
329−-- ## Implementation Details
331−-- We want our `Builder` to be a data structure with
332−-- * *O(1)* monoid append
335−-- Our `Builder` implementation is an unbalanced binary tree.
337−-- For monoid `append`, what we actually get is *O(1)* when either the
338−-- left or right tree is a singleton. If that's not true, then in the
339−-- unlikely worst case `append` might be *O(n)*.
341−-- `Builder` is optimized what we consider to be normal usage, that is,
342−-- `snoc`ing singleton elements to the end of the `Builder`.
344−-- If a Builder is built entirely by `snoc`ing, it will look like a
345−-- left-only binary tree, a.k.a. a linked list.
357−-- If two of these `snoc`-built trees are `append`ed, then the new tree
372−-- This is all similar to
373−-- [__bytestring-tree-builder__](https://hackage.haskell.org/package/bytestring-tree-builder)
375−-- [`Tree`](https://hackage.haskell.org/package/bytestring-tree-builder-0.2.7.3/docs/src/ByteString.TreeBuilder.Tree.html#Tree)
376−-- structure in __bytestring-tree-builder__ only carries values in its
377−-- leaves, which is how it achieves *O(1)* appending, at the cost of
378−-- a higher coefficient time factor on the fold.
380−-- We hope that this implementation is fairly fast, but we
381−-- haven't chosen this implementation because it's fast, we've chosen
382−-- this implementation because it's simple.
383−-- If someone wants to create a fast Purescript ArrayBuffer serialization
384−-- library, then they can benchmark against this one to prove that the new
387−-- One relatively cheap and simple performance improvement for this library would be to
388−-- remove the Null constructor of `Builder` and instead use Javascript nulls.
390−-- In the longer term, it might make sense to try to change the Builder so
391−-- that it works like the
392−-- https://hackage.haskell.org/package/bytestring/docs/Data-ByteString-Builder.html
394−-- Here are some benchmarks of different Haskell ByteString builders
395−-- https://github.com/haskell-perf/strict-bytestring-builders
397−-- We've tried to design the API for this library with minimal assumptions,
398−-- so that if we want to change the Builder implementation later then we can.