From 750cbb6457fe088af380f4f593991d00ad502eef Mon Sep 17 00:00:00 2001
From: Sergey Sharpov <sharpov.sergey@theevenstar.net>
Date: Sun, 15 Dec 2024 18:13:43 +0200
Subject: [PATCH] allow shared array buffer for reading, block for writing

---
 src/byte-stream-writer.ts | 28 ++++++++++++++++++++++++----
 src/byte-stream.ts        | 33 +++++++++++++++++----------------
 2 files changed, 41 insertions(+), 20 deletions(-)

diff --git a/src/byte-stream-writer.ts b/src/byte-stream-writer.ts
index 223998d..414871c 100644
--- a/src/byte-stream-writer.ts
+++ b/src/byte-stream-writer.ts
@@ -82,11 +82,24 @@ const defaultOptions: ResizeOptions = {
   increment: 256
 };
 
+const validateBuffer = (buffer: ArrayBufferLike): ArrayBuffer => {
+  if (SharedArrayBuffer && buffer instanceof SharedArrayBuffer) {
+    throw new TypeError('SharedArrayBuffer writing is not supported');
+  }
+
+  return buffer as ArrayBuffer;
+};
+
 /**
  * A class that provides methods for writing binary data to a buffer.
  * @group Encoding
  */
 export class ByteStreamWriter extends ByteStream {
+  /**
+   * The underlying buffer.
+   */
+  protected override _buffer: ArrayBuffer;
+
   /**
    * The options for buffer resizing.
    */
@@ -110,7 +123,7 @@ export class ByteStreamWriter extends ByteStream {
    * @param buffer - The buffer to write to
    * @throws {@link https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/RangeError | RangeError} if the initial buffer size is invalid or the maxByteLength is less than the initial buffer size
    */
-  public constructor(buffer: ArrayBuffer);
+  public constructor(buffer: ArrayBufferLike);
 
   /**
    * Creates a new buffer writer.
@@ -119,7 +132,7 @@ export class ByteStreamWriter extends ByteStream {
    */
   public constructor(typedArray: TypedArray);
 
-  public constructor(target: number | ArrayBuffer | TypedArray, options: Partial<ResizeOptions> = {}) {
+  public constructor(target: number | ArrayBufferLike | TypedArray, options: Partial<ResizeOptions> = {}) {
     const targetOptions = { ...defaultOptions, ...options };
 
     if (typeof target === 'number') {
@@ -133,9 +146,9 @@ export class ByteStreamWriter extends ByteStream {
 
       super(buffer);
     } else if (ArrayBuffer.isView(target)) {
-      super(target as TypedArray);
+      super(validateBuffer(target.buffer));
     } else {
-      super(target as ArrayBuffer);
+      super(validateBuffer(target));
     }
 
     this._options = targetOptions;
@@ -164,6 +177,13 @@ export class ByteStreamWriter extends ByteStream {
     }
   };
 
+  /**
+   * Returns the underlying buffer
+   */
+  public override get buffer(): ArrayBuffer {
+    return this._buffer;
+  }
+
   /**
    * The current capacity of the buffer.
    */
diff --git a/src/byte-stream.ts b/src/byte-stream.ts
index 463f223..d8aa094 100644
--- a/src/byte-stream.ts
+++ b/src/byte-stream.ts
@@ -1,15 +1,16 @@
 export type TypedArray =
-  | Int8Array<ArrayBuffer>
-  | Uint8Array<ArrayBuffer>
-  | Uint8ClampedArray<ArrayBuffer>
-  | Int16Array<ArrayBuffer>
-  | Uint16Array<ArrayBuffer>
-  | Int32Array<ArrayBuffer>
-  | Uint32Array<ArrayBuffer>
-  | Float32Array<ArrayBuffer>
-  | Float64Array<ArrayBuffer>
-  | BigInt64Array<ArrayBuffer>
-  | BigUint64Array<ArrayBuffer>;
+  | Int8Array
+  | Uint8Array
+  | Uint8ClampedArray
+  | Int16Array
+  | Uint16Array
+  | Int32Array
+  | Uint32Array
+  | Float32Array
+  | Float64Array
+  | BigInt64Array
+  | BigUint64Array;
+
 
 /**
  * Base class for reading and writing binary data.
@@ -19,7 +20,7 @@ export class ByteStream {
   /**
    * The underlying buffer.
    */
-  protected _buffer: ArrayBuffer;
+  protected _buffer: ArrayBufferLike;
 
   /**
    * The DataView instance to read data from the buffer.
@@ -38,9 +39,9 @@ export class ByteStream {
 
   /**
    * Creates a new buffer view.
-   * @param buffer - The ArrayBuffer to read/write data from/to
+   * @param buffer - The ArrayBuffer/SharedArrayBuffer to read/write data from/to
    */
-  public constructor(buffer: ArrayBuffer);
+  public constructor(buffer: ArrayBufferLike);
 
   /**
    * Creates a new buffer view.
@@ -48,7 +49,7 @@ export class ByteStream {
    */
   public constructor(typedArray: TypedArray);
 
-  public constructor(target: ArrayBuffer | TypedArray) {
+  public constructor(target: ArrayBufferLike | TypedArray) {
     if (ArrayBuffer.isView(target)) {
       this._buffer = target.buffer;
       this._offset = target.byteOffset;
@@ -99,7 +100,7 @@ export class ByteStream {
   /**
    * Returns the underlying buffer
    */
-  public get buffer(): ArrayBuffer {
+  public get buffer(): ArrayBufferLike {
     return this._buffer;
   }