1 /*
   2  * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package jdk.nashorn.internal.objects;
  27 
  28 import java.util.Arrays;
  29 import jdk.nashorn.internal.objects.annotations.Attribute;
  30 import jdk.nashorn.internal.objects.annotations.Constructor;
  31 import jdk.nashorn.internal.objects.annotations.Function;
  32 import jdk.nashorn.internal.objects.annotations.Getter;
  33 import jdk.nashorn.internal.objects.annotations.ScriptClass;
  34 import jdk.nashorn.internal.runtime.JSType;
  35 import jdk.nashorn.internal.runtime.PropertyMap;
  36 import jdk.nashorn.internal.runtime.ScriptObject;
  37 import jdk.nashorn.internal.runtime.ScriptRuntime;
  38 
  39 @ScriptClass("ArrayBuffer")
  40 final class NativeArrayBuffer extends ScriptObject {
  41     private final byte[] buffer;
  42 
  43     // initialized by nasgen
  44     private static PropertyMap $nasgenmap$;
  45 
  46     static PropertyMap getInitialMap() {
  47         return $nasgenmap$;
  48     }
  49 
  50     @Constructor(arity = 1)
  51     public static Object constructor(final boolean newObj, final Object self, final Object... args) {
  52         if (args.length == 0) {
  53             throw new RuntimeException("missing length argument");
  54         }
  55 
  56         return new NativeArrayBuffer(JSType.toInt32(args[0]));
  57     }
  58 
  59     protected NativeArrayBuffer(final byte[] byteArray, final Global global) {
  60         super(global.getArrayBufferPrototype(), global.getArrayBufferMap());
  61         this.buffer = byteArray;
  62     }
  63 
  64     protected NativeArrayBuffer(final byte[] byteArray) {
  65         this(byteArray, Global.instance());
  66     }
  67 
  68     protected NativeArrayBuffer(final int byteLength) {
  69         this(new byte[byteLength]);
  70     }
  71 
  72     protected NativeArrayBuffer(final NativeArrayBuffer other, final int begin, final int end) {
  73         this(Arrays.copyOfRange(other.buffer, begin, end));
  74     }
  75 
  76     @Override
  77     public String getClassName() {
  78         return "ArrayBuffer";
  79     }
  80 
  81     @Getter(attributes = Attribute.NOT_ENUMERABLE | Attribute.NOT_WRITABLE | Attribute.NOT_CONFIGURABLE)
  82     public static Object byteLength(final Object self) {
  83         return ((NativeArrayBuffer)self).buffer.length;
  84     }
  85 
  86     @Function(attributes = Attribute.NOT_ENUMERABLE)
  87     public static Object slice(final Object self, final Object begin0, final Object end0) {
  88         final NativeArrayBuffer arrayBuffer = (NativeArrayBuffer)self;
  89         int begin = JSType.toInt32(begin0);
  90         int end = end0 != ScriptRuntime.UNDEFINED ? JSType.toInt32(end0) : arrayBuffer.getByteLength();
  91         begin = adjustIndex(begin, arrayBuffer.getByteLength());
  92         end = adjustIndex(end, arrayBuffer.getByteLength());
  93         return new NativeArrayBuffer((NativeArrayBuffer) self, begin, Math.max(end, begin));
  94     }
  95 
  96     /**
  97      * If index is negative, it refers to an index from the end of the array, as
  98      * opposed to from the beginning. The index is clamped to the valid index
  99      * range for the array.
 100      *
 101      * @param index  The index.
 102      * @param length The length of the array.
 103      * @return valid index index in the range [0, length).
 104      */
 105     static int adjustIndex(final int index, final int length) {
 106         if (index < 0) {
 107             return clamp(index + length, length);
 108         }
 109         return clamp(index, length);
 110     }
 111 
 112     /**
 113      * Clamp index into the range [0, length).
 114      */
 115     private static int clamp(final int index, final int length) {
 116         if (index < 0) {
 117             return 0;
 118         } else if (index > length) {
 119             return length;
 120         }
 121         return index;
 122     }
 123 
 124     public byte[] getByteArray() {
 125         return buffer;
 126     }
 127 
 128     public int getByteLength() {
 129         return buffer.length;
 130     }
 131 }