Initial implementation of TypedArray support.

Author: iwoplaza

src/describe/index.ts

@@ -4,18 +4,19 @@ import {
   SubTypeKey,
   TupleSchema,
 } from '../structure';
-import { DynamicArraySchema } from '../structure/dynamicArray';
+import { ArraySchema } from '../structure/array';
+import { KeyedSchema } from '../structure/keyed';
 import { OptionalSchema } from '../structure/optional';
+import { TypedArraySchema } from '../structure/typedArray';
+import { DynamicArraySchema } from '../structure/dynamicArray';
 import { AnyObjectSchema, GenericObjectSchema } from '../structure/object';
-import { ArraySchema } from '../structure/array';
 import {
   ISchema,
   Ref,
   AnySchema,
   Unwrap,
   AnySchemaWithProperties,
 } from '../structure/types';
-import { KeyedSchema } from '../structure/keyed';
 import { MergeRecordUnion } from '../utilityTypes';
 
 export const chars = <T extends number>(length: T) => new CharsSchema(length);
@@ -56,6 +57,33 @@ export const tupleOf = <TSchema extends [AnySchema, ...AnySchema[]]>(
   schemas: TSchema,
 ) => new TupleSchema(schemas);
 
+export const u8Array = (length: number) =>
+  new TypedArraySchema(length, Uint8Array);
+
+export const u8ClampedArray = (length: number) =>
+  new TypedArraySchema(length, Uint8ClampedArray);
+
+export const u16Array = (length: number) =>
+  new TypedArraySchema(length, Uint16Array);
+
+export const u32Array = (length: number) =>
+  new TypedArraySchema(length, Uint32Array);
+
+export const i8Array = (length: number) =>
+  new TypedArraySchema(length, Int8Array);
+
+export const i16Array = (length: number) =>
+  new TypedArraySchema(length, Int16Array);
+
+export const i32Array = (length: number) =>
+  new TypedArraySchema(length, Int32Array);
+
+export const f32Array = (length: number) =>
+  new TypedArraySchema(length, Float32Array);
+
+export const f64Array = (length: number) =>
+  new TypedArraySchema(length, Float64Array);
+
 export const optional = <TSchema extends AnySchema>(innerType: TSchema) =>
   new OptionalSchema(innerType);
 

src/io/bufferReader.ts

@@ -1,5 +1,5 @@
 import { BufferIOBase, BufferIOOptions } from './bufferIOBase';
-import { ISerialInput } from './types';
+import { ISerialInput, MutableBufferView } from './types';
 
 export class BufferReader extends BufferIOBase implements ISerialInput {
   constructor(buffer: ArrayBufferLike, options?: BufferIOOptions) {
@@ -50,4 +50,12 @@ export class BufferReader extends BufferIOBase implements ISerialInput {
 
     return contents;
   }
+
+  readSlice(
+    bufferView: MutableBufferView,
+    offset: number,
+    length: number,
+  ): void {
+    bufferView.set(this.uint8View.subarray(this.byteOffset, length), offset);
+  }
 }

src/io/bufferWriter.ts

@@ -46,4 +46,9 @@ export class BufferWriter extends BufferIOBase implements ISerialOutput {
     // Extra null character
     this.uint8View[this.byteOffset++] = 0;
   }
+
+  writeSlice(bufferView: ArrayLike<number> & ArrayBufferView): void {
+    this.uint8View.set(bufferView, this.byteOffset);
+    this.byteOffset += bufferView.byteLength;
+  }
 }

src/io/types.ts

@@ -1,12 +1,23 @@
 export type Endianness = 'big' | 'little';
 
+export type ImmutableBufferView = ArrayLike<number> & ArrayBufferView;
+
+export type MutableBufferView = ImmutableBufferView & {
+  set(array: ArrayLike<number>, offset?: number): void;
+};
+
 export interface ISerialInput {
   readBool(): boolean;
   readByte(): number;
   readInt32(): number;
   readUint32(): number;
   readFloat32(): number;
   readString(): string;
+  readSlice(
+    bufferView: MutableBufferView,
+    offset: number,
+    length: number,
+  ): void;
   seekTo(offset: number): void;
   skipBytes(bytes: number): void;
   readonly endianness: Endianness;
@@ -20,6 +31,7 @@ export interface ISerialOutput {
   writeUint32(value: number): void;
   writeFloat32(value: number): void;
   writeString(value: string): void;
+  writeSlice(bufferView: ImmutableBufferView): void;
   seekTo(offset: number): void;
   skipBytes(bytes: number): void;
   readonly endianness: Endianness;

src/structure/typedArray.ts

@@ -0,0 +1,47 @@
+import {
+  type ISerialInput,
+  type ISerialOutput,
+  type IMeasurer,
+  Measurer,
+} from '../io';
+import { MutableBufferView } from '../io/types';
+import { Parsed } from '../utilityTypes';
+import { Schema, MaxValue } from './types';
+
+type TypedArrayConstructor<T> = {
+  readonly BYTES_PER_ELEMENT: number;
+  new (buffer: ArrayBufferLike, offset?: number, length?: number): T;
+};
+
+export class TypedArraySchema<
+  TTypedArray extends MutableBufferView,
+> extends Schema<TTypedArray> {
+  public readonly byteLength: number;
+
+  constructor(
+    public readonly length: number,
+    private readonly _arrayConstructor: TypedArrayConstructor<TTypedArray>,
+  ) {
+    super();
+
+    this.byteLength = length * _arrayConstructor.BYTES_PER_ELEMENT;
+  }
+
+  write(output: ISerialOutput, value: Parsed<TTypedArray>): void {
+    output.writeSlice(value);
+  }
+
+  read(input: ISerialInput): Parsed<TTypedArray> {
+    const buffer = new ArrayBuffer(this.byteLength);
+    const view = new this._arrayConstructor(buffer, 0, this.length);
+    input.readSlice(view, 0, this.byteLength);
+    return view as Parsed<TTypedArray>;
+  }
+
+  measure(
+    _value: Parsed<TTypedArray> | typeof MaxValue,
+    measurer: IMeasurer = new Measurer(),
+  ): IMeasurer {
+    return measurer.add(this.byteLength);
+  }
+}