org.scalajs.javalibintf

Class TypedArrayBuffer

java.lang.Object

org.scalajs.javalibintf.TypedArrayBuffer

public final class TypedArrayBuffer
extends java.lang.Object

Utilities to interface Buffers and JavaScript TypedArrays.

Buffers can be direct buffers or indirect buffers. Indirect buffers use an underlying array (like int[] in Java or Array[Int] in Scala). Direct buffers are supposed to use off-heap memory.

In a JavaScript environment, the equivalent of off-heap memory for buffers of primitive numeric types are TypedArrays.

This class provides methods to wrap TypedArrays as direct Buffers, and extract references to TypedArrays from direct Buffers.

Method Summary

Modifier and Type	Method and Description
static java.lang.Object	arrayBuffer(java.nio.Buffer buffer) Returns the JavaScript ArrayBuffer backing the provided Buffer.
static int	arrayBufferOffset(java.nio.Buffer buffer) Returns the offset within the JavaScript ArrayBuffer backing the provided Buffer.
static java.lang.Object	dataView(java.nio.Buffer buffer) Returns a JavaScript DataView of the provided Buffer.
static boolean	hasArrayBuffer(java.nio.Buffer buffer) Tests whether the given Buffer is backed by an accessible JavaScript ArrayBuffer.
static boolean	hasTypedArray(java.nio.Buffer buffer) Tests whether the given Buffer is backed by an accessible JavaScript TypedArray.
static java.lang.Object	typedArray(java.nio.Buffer buffer) Returns a JavaScript TypedArray view of the provided Buffer.
static java.nio.FloatBuffer	wrapFloat32Array(java.lang.Object array) Wraps a JavaScript Float32Array as a direct FloatBuffer.
static java.nio.DoubleBuffer	wrapFloat64Array(java.lang.Object array) Wraps a JavaScript Float64Array as a direct DoubleBuffer.
static java.nio.ShortBuffer	wrapInt16Array(java.lang.Object array) Wraps a JavaScript Int16Array as a direct ShortBuffer.
static java.nio.IntBuffer	wrapInt32Array(java.lang.Object array) Wraps a JavaScript Int32Array as a direct IntBuffer.
static java.nio.ByteBuffer	wrapInt8Array(java.lang.Object array) Wraps a JavaScript Int8Array as a direct ByteBuffer.
static java.nio.CharBuffer	wrapUint16Array(java.lang.Object array) Wraps a JavaScript Uint16Array as a direct CharBuffer.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

wrapInt8Array

public static final java.nio.ByteBuffer wrapInt8Array(java.lang.Object array)

Wraps a JavaScript Int8Array as a direct ByteBuffer.

The provided array parameter must be a valid JavaScript Int8Array, otherwise the behavior of this method is not specified.

The returned ByteBuffer has the following properties:

• It has a capacity() equal to the array.length.
• Its initial position() is 0 and its limit() is its capacity.
• It is a direct buffer backed by the provided Int8Array: changes to one are reflected on the other.

Parameters:

array - a JavaScript Int8Array

wrapUint16Array

public static final java.nio.CharBuffer wrapUint16Array(java.lang.Object array)

Wraps a JavaScript Uint16Array as a direct CharBuffer.

The provided array parameter must be a valid JavaScript Uint16Array, otherwise the behavior of this method is not specified.

The returned CharBuffer has the following properties:

• It has a capacity() equal to the array.length.
• Its initial position() is 0 and its limit() is its capacity.
• It is a direct buffer backed by the provided Uint16Array: changes to one are reflected on the other.

Parameters:

array - a JavaScript Uint16Array

wrapInt16Array

public static final java.nio.ShortBuffer wrapInt16Array(java.lang.Object array)

Wraps a JavaScript Int16Array as a direct ShortBuffer.

The provided array parameter must be a valid JavaScript Int16Array, otherwise the behavior of this method is not specified.

The returned ShortBuffer has the following properties:

• It has a capacity() equal to the array.length.
• Its initial position() is 0 and its limit() is its capacity.
• It is a direct buffer backed by the provided Int16Array: changes to one are reflected on the other.

Parameters:

array - a JavaScript Int16Array

wrapInt32Array

public static final java.nio.IntBuffer wrapInt32Array(java.lang.Object array)

Wraps a JavaScript Int32Array as a direct IntBuffer.

The provided array parameter must be a valid JavaScript Int32Array, otherwise the behavior of this method is not specified.

The returned IntBuffer has the following properties:

• It has a capacity() equal to the array.length.
• Its initial position() is 0 and its limit() is its capacity.
• It is a direct buffer backed by the provided Int32Array: changes to one are reflected on the other.

Parameters:

array - a JavaScript Int32Array

wrapFloat32Array

public static final java.nio.FloatBuffer wrapFloat32Array(java.lang.Object array)

Wraps a JavaScript Float32Array as a direct FloatBuffer.

The provided array parameter must be a valid JavaScript Float32Array, otherwise the behavior of this method is not specified.

The returned FloatBuffer has the following properties:

• It has a capacity() equal to the array.length.
• Its initial position() is 0 and its limit() is its capacity.
• It is a direct buffer backed by the provided Float32Array: changes to one are reflected on the other.

Parameters:

array - a JavaScript Float32Array

wrapFloat64Array

public static final java.nio.DoubleBuffer wrapFloat64Array(java.lang.Object array)

Wraps a JavaScript Float64Array as a direct DoubleBuffer.

The provided array parameter must be a valid JavaScript Float64Array, otherwise the behavior of this method is not specified.

The returned DoubleBuffer has the following properties:

• It has a capacity() equal to the array.length.
• Its initial position() is 0 and its limit() is its capacity.
• It is a direct buffer backed by the provided Float64Array: changes to one are reflected on the other.

Parameters:

array - a JavaScript Float64Array

hasArrayBuffer

public static final boolean hasArrayBuffer(java.nio.Buffer buffer)

Tests whether the given Buffer is backed by an accessible JavaScript ArrayBuffer.

This is true for all read-write direct buffers, in particular for those created with any of the wrapX methods of this class.

If this method returns true, then arrayBuffer(buffer), arrayBufferOffset(buffer) and dataView(buffer) do not throw any UnsupportedOperationException.

Returns:

true if and only if the provided buffer is backed by an accessible JavaScript ArrayBuffer

See Also:

arrayBuffer(Buffer), arrayBufferOffset(Buffer), dataView(Buffer)

arrayBuffer

public static final java.lang.Object arrayBuffer(java.nio.Buffer buffer)
                                          throws java.lang.UnsupportedOperationException

Returns the JavaScript ArrayBuffer backing the provided Buffer.

The buffer may represent a view of the returned ArrayBuffer that does not start at index 0. Use the method arrayBufferOffset(Buffer) to retrieve the offset within the ArrayBuffer.

Returns:

the JavaScript ArrayBuffer backing the provided buffer

Throws:

java.lang.UnsupportedOperationException - if the provided buffer is read-only or is not backed by a JavaScript ArrayBuffer, i.e., if hasArrayBuffer(buffer) returns false

See Also:

hasArrayBuffer(Buffer), arrayBufferOffset(Buffer)

arrayBufferOffset

public static final int arrayBufferOffset(java.nio.Buffer buffer)
                                   throws java.lang.UnsupportedOperationException

Returns the offset within the JavaScript ArrayBuffer backing the provided Buffer.

Returns:

the offset within the JavaScript ArrayBuffer backing the provided buffer where the latter starts

Throws:

java.lang.UnsupportedOperationException - if the provided buffer is read-only or is not backed by a JavaScript ArrayBuffer, i.e., if hasArrayBuffer(buffer) returns false

See Also:

hasArrayBuffer(Buffer), arrayBuffer(Buffer)

dataView

public static final java.lang.Object dataView(java.nio.Buffer buffer)
                                       throws java.lang.UnsupportedOperationException

Returns a JavaScript DataView of the provided Buffer.

Returns:

a JavaScript DataView of the provided buffer

Throws:

java.lang.UnsupportedOperationException - if the provided buffer is read-only or is not backed by a JavaScript ArrayBuffer, i.e., if hasArrayBuffer(buffer) returns false

See Also:

hasArrayBuffer(Buffer)

hasTypedArray

public static final boolean hasTypedArray(java.nio.Buffer buffer)

Tests whether the given Buffer is backed by an accessible JavaScript TypedArray.

This is true when all of the following conditions apply:

• the buffer is a direct buffer,
• it is not read-only,
• its byte order corresponds to the native byte order of JavaScript TypedArrays, and
• it is not a LongBuffer.

In particular, it is true for all Buffers created with any of the wrapXArray methods of this class.

If this method returns true, then typedArray(buffer) does not throw any UnsupportedOperationException.

Returns:

true if and only if the provided buffer is backed by an accessible JavaScript TypedArray

See Also:

typedArray(Buffer)

typedArray

public static final java.lang.Object typedArray(java.nio.Buffer buffer)
                                         throws java.lang.UnsupportedOperationException

Returns a JavaScript TypedArray view of the provided Buffer.

The particular type of TypedArray depends on the type of buffer:

• an Int8Array for a ByteBuffer
• a Uint16Array for a CharBuffer
• an Int16Array for a ShortBuffer
• an Int32Array for a IntBuffer
• an Float32Array for a FloatBuffer
• an Float64Array for a DoubleBuffer

Returns:

a JavaScript TypedArray view of the provided buffer

Throws:

java.lang.UnsupportedOperationException - if the provided buffer is read-only or is not backed by a JavaScript TypedArray, i.e., if hasTypedArray(buffer) returns false

See Also:

hasTypedArray(Buffer)