dart:typed_data

ByteData class

A fixed-length, random-access sequence of bytes that also provides random and unaligned access to the fixed-width integers and floating point numbers represented by those bytes.

ByteData may be used to pack and unpack data from external sources (such as networks or files systems), and to process large quantities of numerical data more efficiently than would be possible with ordinary List implementations. ByteData can save space, by eliminating the need for object headers, and time, by eliminating the need for data copies.

If data comes in as bytes, they can be converted to ByteData by sharing the same buffer.

Uint8List bytes = ...;
var blob = ByteData.sublistView(bytes);
if (blob.getUint32(0, Endian.little) == 0x04034b50) { // Zip file marker
  ...
}

Finally, ByteData may be used to intentionally reinterpret the bytes representing one arithmetic type as another. For example this code fragment determine what 32-bit signed integer is represented by the bytes of a 32-bit floating point number (both stored as big endian):

var bdata = ByteData(8);
bdata.setFloat32(0, 3.04);
int huh = bdata.getInt32(0); // 0x40428f5c

Implemented types

• TypedData

Implementers

• UnmodifiableByteDataView

Constructors

ByteData(int length)

factory

Creates a ByteData of the specified length (in elements), all of whose bytes are initially zero.

ByteData.sublistView(TypedData data, [int start = 0, int? end])

factory

Creates a ByteData view on a range of elements of data. [...]

ByteData.view(ByteBuffer buffer, [int offsetInBytes = 0, int? length])

factory

Creates an ByteData view of the specified region in buffer. [...]

Properties

buffer → ByteBuffer

read-only, inherited

Returns the byte buffer associated with this object.

elementSizeInBytes → int

read-only, inherited

Returns the number of bytes in the representation of each element in this list.

hashCode → int

read-only, inherited

The hash code for this object. [...]

lengthInBytes → int

read-only, inherited

Returns the length of this view, in bytes.

offsetInBytes → int

read-only, inherited

Returns the offset in bytes into the underlying byte buffer of this view.

runtimeType → Type

read-only, inherited

A representation of the runtime type of the object.

Methods

getFloat32(int byteOffset, [Endian endian = Endian.big]) → double

Returns the floating point number represented by the four bytes at the specified byteOffset in this object, in IEEE 754 single-precision binary floating-point format (binary32). [...]

getFloat64(int byteOffset, [Endian endian = Endian.big]) → double

Returns the floating point number represented by the eight bytes at the specified byteOffset in this object, in IEEE 754 double-precision binary floating-point format (binary64). [...]

getInt8(int byteOffset) → int

Returns the (possibly negative) integer represented by the byte at the specified byteOffset in this object, in two's complement binary representation. [...]

getInt16(int byteOffset, [Endian endian = Endian.big]) → int

Returns the (possibly negative) integer represented by the two bytes at the specified byteOffset in this object, in two's complement binary form. [...]

getInt32(int byteOffset, [Endian endian = Endian.big]) → int

Returns the (possibly negative) integer represented by the four bytes at the specified byteOffset in this object, in two's complement binary form. [...]

getInt64(int byteOffset, [Endian endian = Endian.big]) → int

Returns the (possibly negative) integer represented by the eight bytes at the specified byteOffset in this object, in two's complement binary form. [...]

getUint8(int byteOffset) → int

Returns the positive integer represented by the byte at the specified byteOffset in this object, in unsigned binary form. [...]

getUint16(int byteOffset, [Endian endian = Endian.big]) → int

Returns the positive integer represented by the two bytes starting at the specified byteOffset in this object, in unsigned binary form. [...]

getUint32(int byteOffset, [Endian endian = Endian.big]) → int

Returns the positive integer represented by the four bytes starting at the specified byteOffset in this object, in unsigned binary form. [...]

getUint64(int byteOffset, [Endian endian = Endian.big]) → int

Returns the positive integer represented by the eight bytes starting at the specified byteOffset in this object, in unsigned binary form. [...]

noSuchMethod(Invocation invocation) → dynamic

inherited

Invoked when a non-existent method or property is accessed. [...]

setFloat32(int byteOffset, double value, [Endian endian = Endian.big]) → void

Sets the four bytes starting at the specified byteOffset in this object to the IEEE 754 single-precision binary floating-point (binary32) representation of the specified value. [...]

setFloat64(int byteOffset, double value, [Endian endian = Endian.big]) → void

Sets the eight bytes starting at the specified byteOffset in this object to the IEEE 754 double-precision binary floating-point (binary64) representation of the specified value. [...]

setInt8(int byteOffset, int value) → void

Sets the byte at the specified byteOffset in this object to the two's complement binary representation of the specified value, which must fit in a single byte. [...]

setInt16(int byteOffset, int value, [Endian endian = Endian.big]) → void

Sets the two bytes starting at the specified byteOffset in this object to the two's complement binary representation of the specified value, which must fit in two bytes. [...]

setInt32(int byteOffset, int value, [Endian endian = Endian.big]) → void

Sets the four bytes starting at the specified byteOffset in this object to the two's complement binary representation of the specified value, which must fit in four bytes. [...]

setInt64(int byteOffset, int value, [Endian endian = Endian.big]) → void

Sets the eight bytes starting at the specified byteOffset in this object to the two's complement binary representation of the specified value, which must fit in eight bytes. [...]

setUint8(int byteOffset, int value) → void

Sets the byte at the specified byteOffset in this object to the unsigned binary representation of the specified value, which must fit in a single byte. [...]

setUint16(int byteOffset, int value, [Endian endian = Endian.big]) → void

Sets the two bytes starting at the specified byteOffset in this object to the unsigned binary representation of the specified value, which must fit in two bytes. [...]

setUint32(int byteOffset, int value, [Endian endian = Endian.big]) → void

Sets the four bytes starting at the specified byteOffset in this object to the unsigned binary representation of the specified value, which must fit in four bytes. [...]

setUint64(int byteOffset, int value, [Endian endian = Endian.big]) → void

Sets the eight bytes starting at the specified byteOffset in this object to the unsigned binary representation of the specified value, which must fit in eight bytes. [...]

toString() → String

inherited

A string representation of this object. [...]

Operators

operator ==(Object other) → bool

inherited

The equality operator. [...]