ArrayBuffer.md

ArrayBuffer

Namespace: SpawnDev.SpawnJS.JSObjects
Inheritance: SpawnJSObject -> ArrayBuffer
Attribute: [Transferable]
MDN Reference: ArrayBuffer - MDN

The ArrayBuffer object represents a generic raw binary data buffer. It is an array of bytes, often referred to in other languages as a "byte array". You cannot directly manipulate the contents of an ArrayBuffer; instead, you create a typed array view or a DataView to read and write the buffer contents. SpawnDev.SpawnJS extends this class with Create factory methods that use HeapView for fast zero-copy transfers from .NET arrays, and explicit cast operators for common .NET types.

Constructors

Signature	Description
ArrayBuffer(long length)	Creates an ArrayBuffer of the specified size in bytes, initialized to zeros.
ArrayBuffer(long length, ArrayBufferOptions options)	Creates an ArrayBuffer with the specified size and additional options (e.g., maxByteLength for resizable buffers).
ArrayBuffer(SpawnJSObjectReference _ref)	Deserialization constructor - wraps an existing JS reference.

Properties

Property	Type	Description
ByteLength	long	The size, in bytes, of the ArrayBuffer. Established at construction and can only be changed via Resize() if the buffer is resizable.
MaxByteLength	long	The read-only maximum length, in bytes, that the ArrayBuffer can be resized to. Established at construction.
Detached	bool	Read-only. Returns true if the ArrayBuffer has been detached (transferred), false otherwise.
Resizable	bool	Read-only. Returns true if the ArrayBuffer can be resized, false otherwise.
IsSharedArrayBuffer	bool	Returns true if the underlying JS object is actually a SharedArrayBuffer. Aids interop when using SharedArrayBuffer through ArrayBuffer-typed APIs.
IsArrayBuffer	bool	Returns true if the underlying JS object is an ArrayBuffer (not a SharedArrayBuffer).

Static Methods

Method	Return Type	Description
IsView(object value)	bool	Returns true if value is one of the ArrayBuffer views (typed array or DataView).
Create<T>(T[] data, long offset = 0)	ArrayBuffer	Creates a new ArrayBuffer containing a copy of the .NET struct array, starting at the given offset. Uses HeapView for fast copy.
Create<T>(T[] data, long offset, long length)	ArrayBuffer	Creates a new ArrayBuffer containing a copy of length elements from the .NET struct array, starting at offset.
Create(string data, long offset = 0)	ArrayBuffer	Creates a new ArrayBuffer from a string's internal character data (UTF-16).
Create(string data, long offset, long length)	ArrayBuffer	Creates a new ArrayBuffer from length characters of the string, starting at offset.

Instance Methods

Method	Return Type	Description
ReadBytes()	byte[]	Reads the entire ArrayBuffer content into a .NET byte[]. Internally creates a Uint8Array view.
Slice()	ArrayBuffer	Returns a new ArrayBuffer containing a copy of all bytes.
Slice(long start)	ArrayBuffer	Returns a new ArrayBuffer from start (inclusive) to the end. Negative values count from the end.
Slice(long start, long end)	ArrayBuffer	Returns a new ArrayBuffer from start (inclusive) to end (exclusive).
Resize(long newLength)	void	Resizes the ArrayBuffer to newLength bytes. Only works on resizable buffers.
Transfer()	ArrayBuffer	Creates a new ArrayBuffer with the same content, then detaches this buffer.
Transfer(long newByteLength)	ArrayBuffer	Creates a new ArrayBuffer of newByteLength with the same content (truncated or zero-padded), then detaches this buffer.
TransferToFixedLength()	ArrayBuffer	Creates a new non-resizable ArrayBuffer with the same content, then detaches this buffer.
TransferToFixedLength(long newByteLength)	ArrayBuffer	Creates a new non-resizable ArrayBuffer of newByteLength, then detaches this buffer.

Explicit Cast Operators

SpawnDev.SpawnJS provides explicit cast operators using HeapView for fast data transfer between .NET arrays and ArrayBuffer.

Cast	Description
(ArrayBuffer)byte[]	Copies a byte[] to a new ArrayBuffer.
(byte[])ArrayBuffer	Reads an ArrayBuffer into a byte[]. Returns null if the source is null.
(ArrayBuffer)string	Copies a string's character data (UTF-16) to a new ArrayBuffer.
(ArrayBuffer)sbyte[]	Copies an sbyte[] to a new ArrayBuffer.
(ArrayBuffer)short[]	Copies a short[] to a new ArrayBuffer.
(ArrayBuffer)ushort[]	Copies a ushort[] to a new ArrayBuffer.
(ArrayBuffer)int[]	Copies an int[] to a new ArrayBuffer.
(ArrayBuffer)uint[]	Copies a uint[] to a new ArrayBuffer.
(ArrayBuffer)long[]	Copies a long[] to a new ArrayBuffer.
(ArrayBuffer)ulong[]	Copies a ulong[] to a new ArrayBuffer.
(ArrayBuffer)Half[]	Copies a Half[] to a new ArrayBuffer.
(ArrayBuffer)float[]	Copies a float[] to a new ArrayBuffer.
(ArrayBuffer)double[]	Copies a double[] to a new ArrayBuffer.

Example

// Create from .NET data
byte[] myData = new byte[] { 0x48, 0x65, 0x6C, 0x6C, 0x6F };
using var buffer = (ArrayBuffer)myData;

// Read properties
Console.WriteLine($"ByteLength: {buffer.ByteLength}");    // 5
Console.WriteLine($"Detached: {buffer.Detached}");         // false
Console.WriteLine($"Resizable: {buffer.Resizable}");       // false

// Read back to .NET
byte[] readBack = buffer.ReadBytes();
byte[] alsoWorks = (byte[])buffer;

// Slice a portion
using var sliced = buffer.Slice(1, 4);  // bytes at index 1, 2, 3
Console.WriteLine($"Sliced length: {sliced.ByteLength}");  // 3

// Create from float array using generic factory
float[] floats = new float[] { 1.0f, 2.0f, 3.0f };
using var floatBuffer = ArrayBuffer.Create(floats);
Console.WriteLine($"Float buffer size: {floatBuffer.ByteLength}");  // 12

// Transfer detaches the original
using var transferred = buffer.Transfer();
Console.WriteLine($"Original detached: {buffer.Detached}");  // true