description

# ByteData class Null safety

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

Implemented types
  - TypedData
Implementers
  - UnmodifiableByteDataView

## Constructors

ByteData(int length)
  Creates a ByteData of the specified length (in elements), all of whose bytes are initially zero.
  factory
ByteData.sublistView(TypedData data, [int start = 0, int? end])
  Creates a ByteData view on a range of elements of `data`. [...]
  factory
ByteData.view(ByteBuffer buffer, [int offsetInBytes = 0, int? length])
  Creates an ByteData view of the specified region in `buffer`. [...]
  factory

## Properties

buffer → ByteBuffer
  Returns the byte buffer associated with this object.
  read-only, inherited
elementSizeInBytes → int
  Returns the number of bytes in the representation of each element in this list.
  read-only, inherited
hashCode → int
  The hash code for this object. [...]
  read-only, inherited
lengthInBytes → int
  Returns the length of this view, in bytes.
  read-only, inherited
offsetInBytes → int
  Returns the offset in bytes into the underlying byte buffer of this view.
  read-only, inherited
runtimeType → Type
  A representation of the runtime type of the object.
  read-only, inherited

## 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
  Invoked when a non-existent method or property is accessed. [...]
  inherited
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
  Returns a string representation of this object.
  inherited

## Operators

operator ==(Object other) → bool
  The equality operator. [...]
  inherited