First step towards implementing dart:typeddata library.

sdk/lib/typeddata/typeddata_base.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+part of dart.typeddata;
+
+/**
+ * A sequence of bytes underlying a typed data object.
+ * Used to process large quantities of binary or numerical data
+ * more efficiently using a typed view.
+ */
+abstract class ByteBuffer {
+  /**
+   * Returns the length of this byte buffer, in bytes.
+   */
+  int get lengthInBytes;
+
+}
+
+
+/**
+ * A typed view of a sequence of bytes.
+ */
+abstract class TypedData {
+  /**
+   * Returns the number of bytes in the representation of each element in this
+   * list.
+   */
+  int get elementSizeInBytes;
+
+  /**
+   * Returns the offset in bytes into the underlying byte buffer of this view.
+   */
+  int get offsetInBytes;
+
+  /**
+   * Returns the length of this view, in bytes.
+   */
+  int get lengthInBytes;
+
+  /**
+   * Returns the byte buffer associated with this object.
+   */
+  ByteBuffer get buffer;
+}
+
+
+/**
+ * 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. 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:
+ *
+ *     var buffer = new Uint8List(8).buffer;
+ *     var bdata = new ByteData.view(buffer);
+ *     bdata.setFloat32(0, 3.04);
+ *     int huh = bdata.getInt32(0);
+ */
+abstract class ByteData implements TypedData {
+  /**
+   * Creates a [ByteData] of the specified length (in elements), all of
+   * whose elements are initially zero.
+   */
+  external factory ByteData(int length);
+
+  /**
+   * Creates an [ByteData] _view_ of the specified region in the specified
+   * byte buffer. Changes in the [ByteData] will be visible in the byte
+   * buffer and vice versa. If the [offsetInBytes] index of the region is not
+   * specified, it defaults to zero (the first byte in the byte buffer).
+   * If the length is not specified, it defaults to null, which indicates
+   * that the view extends to the end of the byte buffer.
+   *
+   * Throws [RangeError] if [offsetInBytes] or [length] are negative, or
+   * if [offsetInBytes] + ([length] * elementSizeInBytes) is greater than
+   * the length of [buffer].
+   */
+  external factory ByteData.view(ByteBuffer buffer,
+                                 [int offsetInBytes = 0, int length]);
+
+  /**
+   * Returns the (possibly negative) integer represented by the byte at the
+   * specified [byteOffset] in this object, in two's complement binary
+   * representation. The return value will be between -128 and 127, inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * greater than or equal to the length of this object.
+   */
+  int getInt8(int byteOffset);
+
+  /**
+   * 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. In other words, [value] must be between
+   * -128 and 127, inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * greater than or equal to the length of this object.
+   */
+  void setInt8(int byteOffset, int value);
+
+  /**
+   * Returns the positive integer represented by the byte at the specified
+   * [byteOffset] in this object, in unsigned binary form. The
+   * return value will be between 0 and 255, inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * greater than or equal to the length of this object.
+   */
+  int getUint8(int byteOffset);
+
+  /**
+   * 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. in other words, [value] must be between 0 and 255,
+   * inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative,
+   * or greater than or equal to the length of this object.
+   */
+  void setUint8(int byteOffset, int value);
+
+  /**
+   * Returns the (possibly negative) integer represented by the two bytes at
+   * the specified [byteOffset] in this object, in two's complement binary
+   * form.
+   * The return value will be between 2<sup>15</sup> and 2<sup>15</sup> - 1,
+   * inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 2` is greater than the length of this object.
+   */
+  int getInt16(int byteOffset);
+
+  /**
+   * 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. In other words, [value] must lie
+   * between 2<sup>15</sup> and 2<sup>15</sup> - 1, inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 2` is greater than the length of this object.
+   */
+  void setInt16(int byteOffset, int value);
+
+  /**
+   * Returns the positive integer represented by the two bytes starting
+   * at the specified [byteOffset] in this object, in unsigned binary
+   * form.
+   * The return value will be between 0 and  2<sup>16</sup> - 1, inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 2` is greater than the length of this object.
+   */
+  int getUint16(int byteOffset);
+
+  /**
+   * 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. in other words, [value] must be between
+   * 0 and 2<sup>16</sup> - 1, inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 2` is greater than the length of this object.
+   */
+  void setUint16(int byteOffset, int value);
+
+  /**
+   * Returns the (possibly negative) integer represented by the four bytes at
+   * the specified [byteOffset] in this object, in two's complement binary
+   * form.
+   * The return value will be between 2<sup>31</sup> and 2<sup>31</sup> - 1,
+   * inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 4` is greater than the length of this object.
+   */
+  int getInt32(int byteOffset);
+
+  /**
+   * 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. In other words, [value] must lie
+   * between 2<sup>31</sup> and 2<sup>31</sup> - 1, inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 4` is greater than the length of this object.
+   */
+  void setInt32(int byteOffset, int value);
+
+  /**
+   * Returns the positive integer represented by the four bytes starting
+   * at the specified [byteOffset] in this object, in unsigned binary
+   * form.
+   * The return value will be between 0 and  2<sup>32</sup> - 1, inclusive.
+   *
+   */
+  int getUint32(int byteOffset);
+
+  /**
+   * 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. in other words, [value] must be between
+   * 0 and 2<sup>32</sup> - 1, inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 4` is greater than the length of this object.
+   */
+  void setUint32(int byteOffset, int value);
+
+  /**
+   * Returns the (possibly negative) integer represented by the eight bytes at
+   * the specified [byteOffset] in this object, in two's complement binary
+   * form.
+   * The return value will be between 2<sup>63</sup> and 2<sup>63</sup> - 1,
+   * inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 8` is greater than the length of this object.
+   */
+  int getInt64(int byteOffset);
+
+  /**
+   * 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. In other words, [value] must lie
+   * between 2<sup>63</sup> and 2<sup>63</sup> - 1, inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 8` is greater than the length of this object.
+   */
+  void setInt64(int byteOffset, int value);
+
+  /**
+   * Returns the positive integer represented by the eight bytes starting
+   * at the specified [byteOffset] in this object, in unsigned binary
+   * form.
+   * The return value will be between 0 and  2<sup>64</sup> - 1, inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 8` is greater than the length of this object.
+   */
+  int getUint64(int byteOffset);
+
+  /**
+   * 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. in other words, [value] must be between
+   * 0 and 2<sup>64</sup> - 1, inclusive.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 8` is greater than the length of this object.
+   */
+  void setUint64(int byteOffset, int value);
+
+  /**
+   * 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).
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 4` is greater than the length of this object.
+   */
+  double getFloat32(int byteOffset);
+
+  /**
+   * 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].
+   *
+   * **Note that this method can lose precision.** The input [value] is
+   * a 64-bit floating point value, which will be converted to 32-bit
+   * floating point value by IEEE 754 rounding rules before it is stored.
+   * If [value] cannot be represented exactly as a binary32, it will be
+   * converted to the nearest binary32 value.  If two binary32 values are
+   * equally close, the one whose least significant bit is zero will be used.
+   * Note that finite (but large) values can be converted to infinity, and
+   * small non-zero values can be converted to zero.
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 4` is greater than the length of this object.
+   */
+  void setFloat32(int byteOffset, double value);
+
+  /**
+   * 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).
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 8` is greater than the length of this object.
+   */
+  double getFloat64(int byteOffset);
+
+  /**
+   * 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].
+   *
+   * Throws [RangeError] if [byteOffset] is negative, or
+   * `byteOffset + 8` is greater than the length of this object.
+   */
+  void setFloat64(int byteOffset, double value);
+}
+
+
+/**
+ * A fixed-length list of 8-bit signed integers.
+ * For long lists, this implementation can be considerably
+ * more space- and time-efficient than the default [List] implementation.
+ */
+abstract class Int8List implements List<int>, TypedData {
+  /**
+   * Creates an [Int8List] of the specified length (in elements), all of
+   * whose elements are initially zero.
+   */
+  external factory Int8List(int length);
+
+  /**
+   * Creates an [Int8List] _view_ of the specified region in the specified
+   * byte buffer. Changes in the [Int8List] will be visible in the byte
+   * buffer and vice versa. If the [offsetInBytes] index of the region is not
+   * specified, it defaults to zero (the first byte in the byte buffer).
+   * If the length is not specified, it defaults to null, which indicates
+   * that the view extends to the end of the byte buffer.
+   *
+   * Throws [RangeError] if [offsetInBytes] or [length] are negative, or
+   * if [offsetInBytes] + ([length] * elementSizeInBytes) is greater than
+   * the length of [buffer].
+   */
+  external factory Int8List.view(ByteBuffer buffer,
+                                 [int offsetInBytes = 0, int length]);
+
+  static const int BYTES_PER_ELEMENT = 1;
+}
+
+
+/**
+ * A fixed-length list of 8-bit unsigned integers.
+ * For long lists, this implementation can be considerably
+ * more space- and time-efficient than the default [List] implementation.
+ */
+abstract class Uint8List implements List<int>, TypedData {
+  /**
+   * Creates a [Uint8List] of the specified length (in elements), all of
+   * whose elements are initially zero.
+   */
+  external factory Uint8List(int length);
+
+  /**
+   * Creates a [Uint8List] _view_ of the specified region in the specified
+   * byte buffer. Changes in the [Uint8List] will be visible in the byte
+   * buffer and vice versa. If the [offsetInBytes] index of the region is not
+   * specified, it defaults to zero (the first byte in the byte buffer).
+   * If the length is not specified, it defaults to null, which indicates
+   * that the view extends to the end of the byte buffer.
+   *
+   * Throws [RangeError] if [offsetInBytes] or [length] are negative, or
+   * if [offsetInBytes] + ([length] * elementSizeInBytes) is greater than
+   * the length of [buffer].
+   */
+  external factory Uint8List.view(ByteBuffer buffer,
+                                  [int offsetInBytes = 0, int length]);
+
+  static const int BYTES_PER_ELEMENT = 1;
+}
+
+
+/**
+ * A fixed-length list of 8-bit unsigned integers.
+ * For long lists, this implementation can be considerably
+ * more space- and time-efficient than the default [List] implementation.
+ * Indexed store clamps the value to range 0..0xFF.
+ */
+abstract class Uint8ClampedList implements List<int>, TypedData {
+  /**
+   * Creates a [Uint8ClampedList] of the specified length (in elements), all of
+   * whose elements are initially zero.
+   */
+  external factory Uint8ClampedList(int length);
+
+  /**
+   * Creates a [Uint8ClampedList] _view_ of the specified region in the
+   * specified byte [buffer]. Changes in the [Uint8List] will be visible in the
+   * byte buffer and vice versa. If the [offsetInBytes] index of the region is
+   * not specified, it defaults to zero (the first byte in the byte buffer).
+   * If the length is not specified, it defaults to null, which indicates that
+   * the view extends to the end of the byte buffer.
+   *
+   * Throws [RangeError] if [offsetInBytes] or [length] are negative, or
+   * if [offsetInBytes] + ([length] * elementSizeInBytes) is greater than
+   * the length of [buffer].
+   */
+  external factory Uint8ClampedList.view(ByteBuffer buffer,
+                                         [int offsetInBytes = 0, int length]);
+
+  static const int BYTES_PER_ELEMENT = 1;
+}
+
+
+/**
+ * A fixed-length list of 16-bit signed integers that is viewable as a
+ * [TypedData]. For long lists, this implementation can be considerably
+ * more space- and time-efficient than the default [List] implementation.
+ */
+abstract class Int16List implements List<int>, TypedData {
+  /**
+   * Creates an [Int16List] of the specified length (in elements), all of
+   * whose elements are initially zero.
+   */
+  external factory Int16List(int length);
+
+  /**
+   * Creates an [Int16List] _view_ of the specified region in the specified
+   * byte buffer. Changes in the [Int16List] will be visible in the byte
+   * buffer and vice versa. If the [offsetInBytes] index of the region is not
+   * specified, it defaults to zero (the first byte in the byte buffer).
+   * If the length is not specified, it defaults to null, which indicates
+   * that the view extends to the end of the byte buffer.
+   *
+   * Throws [RangeError] if [offsetInBytes] or [length] are negative, or
+   * if [offsetInBytes] + ([length] * elementSizeInBytes) is greater than
+   * the length of [buffer].
+   *
+   * Throws [ArgumentError] if [offsetInBytes] is not a multiple of
+   * BYTES_PER_ELEMENT.
+   */
+  external factory Int16List.view(ByteBuffer buffer,
+                                  [int offsetInBytes = 0, int length]);
+
+  static const int BYTES_PER_ELEMENT = 2;
+}
+
+
+/**
+ * A fixed-length list of 16-bit unsigned integers that is viewable as a
+ * [TypedData]. For long lists, this implementation can be considerably
+ * more space- and time-efficient than the default [List] implementation.
+ */
+abstract class Uint16List implements List<int>, TypedData {
+  /**
+   * Creates a [Uint16List] of the specified length (in elements), all
+   * of whose elements are initially zero.
+   */
+  external factory Uint16List(int length);
+
+  /**
+   * Creates a [Uint16List] _view_ of the specified region in
+   * the specified byte buffer. Changes in the [Uint16List] will be
+   * visible in the byte buffer and vice versa. If the [offsetInBytes] index
+   * of the region is not specified, it defaults to zero (the first byte in
+   * the byte buffer). If the length is not specified, it defaults to null,
+   * which indicates that the view extends to the end of the byte buffer.
+   *
+   * Throws [RangeError] if [offsetInBytes] or [length] are negative, or
+   * if [offsetInBytes] + ([length] * elementSizeInBytes) is greater than
+   * the length of [buffer].
+   *
+   * Throws [ArgumentError] if [offsetInBytes] is not a multiple of
+   * BYTES_PER_ELEMENT.
+   */
+  external factory Uint16List.view(ByteBuffer buffer,
+                                   [int offsetInBytes = 0, int length]);
+
+  static const int BYTES_PER_ELEMENT = 2;
+}
+
+
+/**
+ * A fixed-length list of 32-bit signed integers that is viewable as a
+ * [TypedData]. For long lists, this implementation can be considerably
+ * more space- and time-efficient than the default [List] implementation.
+ */
+abstract class Int32List implements List<int>, TypedData {
+  /**
+   * Creates an [Int32List] of the specified length (in elements), all of
+   * whose elements are initially zero.
+   */
+  external factory Int32List(int length);
+
+  /**
+   * Creates an [Int32List] _view_ of the specified region in the specified
+   * byte buffer. Changes in the [Int32List] will be visible in the byte
+   * buffer and vice versa. If the [offsetInBytes] index of the region is not
+   * specified, it defaults to zero (the first byte in the byte buffer).
+   * If the length is not specified, it defaults to null, which indicates
+   * that the view extends to the end of the byte buffer.
+   *
+   * Throws [RangeError] if [offsetInBytes] or [length] are negative, or
+   * if [offsetInBytes] + ([length] * elementSizeInBytes) is greater than
+   * the length of [buffer].
+   *
+   * Throws [ArgumentError] if [offsetInBytes] is not a multiple of
+   * BYTES_PER_ELEMENT.
+   */
+  external factory Int32List.view(ByteBuffer buffer,
+                                  [int offsetInBytes = 0, int length]);
+
+  static const int BYTES_PER_ELEMENT = 4;
+}
+
+
+/**
+ * A fixed-length list of 32-bit unsigned integers that is viewable as a
+ * [TypedData]. For long lists, this implementation can be considerably
+ * more space- and time-efficient than the default [List] implementation.
+ */
+abstract class Uint32List implements List<int>, TypedData {
+  /**
+   * Creates a [Uint32List] of the specified length (in elements), all
+   * of whose elements are initially zero.
+   */
+  external factory Uint32List(int length);
+
+  /**
+   * Creates a [Uint32List] _view_ of the specified region in
+   * the specified byte buffer. Changes in the [Uint32] will be
+   * visible in the byte buffer and vice versa. If the [offsetInBytes] index
+   * of the region is not specified, it defaults to zero (the first byte in
+   * the byte buffer). If the length is not specified, it defaults to null,
+   * which indicates that the view extends to the end of the byte buffer.
+   *
+   * Throws [RangeError] if [offsetInBytes] or [length] are negative, or
+   * if [offsetInBytes] + ([length] * elementSizeInBytes) is greater than
+   * the length of [buffer].
+   *
+   * Throws [ArgumentError] if [offsetInBytes] is not a multiple of
+   * BYTES_PER_ELEMENT.
+   */
+  external factory Uint32List.view(ByteBuffer buffer,
+                                   [int offsetInBytes = 0, int length]);
+
+  static const int BYTES_PER_ELEMENT = 4;
+}
+
+
+/**
+ * A fixed-length list of 64-bit signed integers that is viewable as a
+ * [TypedData]. For long lists, this implementation can be considerably
+ * more space- and time-efficient than the default [List] implementation.
+ */
+abstract class Int64List implements List<int>, TypedData {
+  /**
+   * Creates an [Int64List] of the specified length (in elements), all of
+   * whose elements are initially zero.
+   */
+  external factory Int64List(int length);
+
+  /**
+   * Creates an [Int64List] _view_ of the specified region in the specified
+   * byte buffer. Changes in the [Int64List] will be visible in the byte buffer
+   * and vice versa. If the [offsetInBytes] index of the region is not
+   * specified, it defaults to zero (the first byte in the byte buffer).
+   * If the length is not specified, it defaults to null, which indicates that
+   * the view extends to the end of the byte buffer.
+   *
+   * Throws [RangeError] if [offsetInBytes] or [length] are negative, or
+   * if [offsetInBytes] + ([length] * elementSizeInBytes) is greater than
+   * the length of [buffer].
+   *
+   * Throws [ArgumentError] if [offsetInBytes] is not a multiple of
+   * BYTES_PER_ELEMENT.
+   */
+  external factory Int64List.view(ByteBuffer buffer,
+                                  [int offsetInBytes = 0, int length]);
+
+  static const int BYTES_PER_ELEMENT = 8;
+}
+
+
+/**
+ * A fixed-length list of 64-bit unsigned integers that is viewable as a
+ * [TypedData]. For long lists, this implementation can be considerably
+ * more space- and time-efficient than the default [List] implementation.
+ */
+abstract class Uint64List implements List<int>, TypedData {
+  /**
+   * Creates a [Uint64List] of the specified length (in elements), all
+   * of whose elements are initially zero.
+   */
+  external factory Uint64List(int length);
+
+  /**
+   * Creates an [Uint64List] _view_ of the specified region in
+   * the specified byte buffer. Changes in the [Uint64List] will be
+   * visible in the byte buffer and vice versa. If the [offsetInBytes]
+   * index of the region is not specified, it defaults to zero (the first
+   * byte in the byte buffer). If the length is not specified, it defaults
+   * to null, which indicates that the view extends to the end of the byte
+   * buffer.
+   *
+   * Throws [RangeError] if [offsetInBytes] or [length] are negative, or
+   * if [offsetInBytes] + ([length] * elementSizeInBytes) is greater than
+   * the length of [buffer].
+   *
+   * Throws [ArgumentError] if [offsetInBytes] is not a multiple of
+   * BYTES_PER_ELEMENT.
+   */
+  external factory Uint64List.view(ByteBuffer buffer,
+                                   [int offsetInBytes = 0, int length]);
+
+  static const int BYTES_PER_ELEMENT = 8;
+}
+
+
+/**
+ * A fixed-length list of IEEE 754 single-precision binary floating-point
+ * numbers  that is viewable as a [TypedData]. For long lists, this
+ * implementation can be considerably more space- and time-efficient than
+ * the default [List] implementation.
+ */
+abstract class Float32List implements List<double>, TypedData {
+  /**
+   * Creates a [Float32List] of the specified length (in elements), all of
+   * whose elements are initially zero.
+   */
+  external factory Float32List(int length);
+
+  /**
+   * Creates a [Float32List] _view_ of the specified region in the specified
+   * byte buffer. Changes in the [Float32List] will be visible in the byte
+   * buffer and vice versa. If the [offsetInBytes] index of the region is not
+   * specified, it defaults to zero (the first byte in the byte buffer).
+   * If the length is not specified, it defaults to null, which indicates
+   * that the view extends to the end of the byte buffer.
+   *
+   * Throws [RangeError] if [offsetInBytes] or [length] are negative, or
+   * if [offsetInBytes] + ([length] * elementSizeInBytes) is greater than
+   * the length of [buffer].
+   *
+   * Throws [ArgumentError] if [offsetInBytes] is not a multiple of
+   * BYTES_PER_ELEMENT.
+   */
+  external factory Float32List.view(ByteBuffer buffer,
+                                    [int offsetInBytes = 0, int length]);
+
+  static const int BYTES_PER_ELEMENT = 4;
+}
+
+
+/**
+ * A fixed-length list of IEEE 754 double-precision binary floating-point
+ * numbers  that is viewable as a [TypedData]. For long lists, this
+ * implementation can be considerably more space- and time-efficient than
+ * the default [List] implementation.
+ */
+abstract class Float64List implements List<double>, TypedData {
+  /**
+   * Creates a [Float64List] of the specified length (in elements), all of
+   * whose elements are initially zero.
+   */
+  external factory Float64List(int length);
+
+  /**
+   * Creates a [Float64List] _view_ of the specified region in the specified
+   * byte buffer. Changes in the [Float64List] will be visible in the byte
+   * buffer and vice versa. If the [offsetInBytes] index of the region is not
+   * specified, it defaults to zero (the first byte in the byte buffer).
+   * If the length is not specified, it defaults to null, which indicates
+   * that the view extends to the end of the byte buffer.
+   *
+   * Throws [RangeError] if [offsetInBytes] or [length] are negative, or
+   * if [offsetInBytes] + ([length] * elementSizeInBytes) is greater than
+   * the length of [buffer].
+   *
+   * Throws [ArgumentError] if [offsetInBytes] is not a multiple of
+   * BYTES_PER_ELEMENT.
+   */
+  external factory Float64List.view(ByteBuffer buffer,
+                                    [int offsetInBytes = 0, int length]);
+
+  static const int BYTES_PER_ELEMENT = 8;
+}