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| 1 // Copyright 2014 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. |
| 4 |
| 5 define("mojo/public/js/bindings/buffer", function() { |
| 6 |
| 7 var kHostIsLittleEndian = (function () { |
| 8 var endianArrayBuffer = new ArrayBuffer(2); |
| 9 var endianUint8Array = new Uint8Array(endianArrayBuffer); |
| 10 var endianUint16Array = new Uint16Array(endianArrayBuffer); |
| 11 endianUint16Array[0] = 1; |
| 12 return endianUint8Array[0] == 1; |
| 13 })(); |
| 14 |
| 15 var kHighWordMultiplier = 0x100000000; |
| 16 |
| 17 function Buffer(sizeOrArrayBuffer) { |
| 18 if (sizeOrArrayBuffer instanceof ArrayBuffer) |
| 19 this.arrayBuffer = sizeOrArrayBuffer; |
| 20 else |
| 21 this.arrayBuffer = new ArrayBuffer(sizeOrArrayBuffer); |
| 22 |
| 23 this.dataView = new DataView(this.arrayBuffer); |
| 24 this.next = 0; |
| 25 } |
| 26 |
| 27 Object.defineProperty(Buffer.prototype, "byteLength", { |
| 28 get: function() { return this.arrayBuffer.byteLength; } |
| 29 }); |
| 30 |
| 31 Buffer.prototype.alloc = function(size) { |
| 32 var pointer = this.next; |
| 33 this.next += size; |
| 34 if (this.next > this.byteLength) { |
| 35 var newSize = (1.5 * (this.byteLength + size)) | 0; |
| 36 this.grow(newSize); |
| 37 } |
| 38 return pointer; |
| 39 }; |
| 40 |
| 41 function copyArrayBuffer(dstArrayBuffer, srcArrayBuffer) { |
| 42 (new Uint8Array(dstArrayBuffer)).set(new Uint8Array(srcArrayBuffer)); |
| 43 } |
| 44 |
| 45 Buffer.prototype.grow = function(size) { |
| 46 var newArrayBuffer = new ArrayBuffer(size); |
| 47 copyArrayBuffer(newArrayBuffer, this.arrayBuffer); |
| 48 this.arrayBuffer = newArrayBuffer; |
| 49 this.dataView = new DataView(this.arrayBuffer); |
| 50 }; |
| 51 |
| 52 Buffer.prototype.trim = function() { |
| 53 this.arrayBuffer = this.arrayBuffer.slice(0, this.next); |
| 54 this.dataView = new DataView(this.arrayBuffer); |
| 55 }; |
| 56 |
| 57 Buffer.prototype.getUint8 = function(offset) { |
| 58 return this.dataView.getUint8(offset); |
| 59 } |
| 60 Buffer.prototype.getUint16 = function(offset) { |
| 61 return this.dataView.getUint16(offset, kHostIsLittleEndian); |
| 62 } |
| 63 Buffer.prototype.getUint32 = function(offset) { |
| 64 return this.dataView.getUint32(offset, kHostIsLittleEndian); |
| 65 } |
| 66 Buffer.prototype.getUint64 = function(offset) { |
| 67 var lo, hi; |
| 68 if (kHostIsLittleEndian) { |
| 69 lo = this.dataView.getUint32(offset, kHostIsLittleEndian); |
| 70 hi = this.dataView.getUint32(offset + 4, kHostIsLittleEndian); |
| 71 } else { |
| 72 hi = this.dataView.getUint32(offset, kHostIsLittleEndian); |
| 73 lo = this.dataView.getUint32(offset + 4, kHostIsLittleEndian); |
| 74 } |
| 75 return lo + hi * kHighWordMultiplier; |
| 76 } |
| 77 |
| 78 Buffer.prototype.getInt8 = function(offset) { |
| 79 return this.dataView.getInt8(offset); |
| 80 } |
| 81 Buffer.prototype.getInt16 = function(offset) { |
| 82 return this.dataView.getInt16(offset, kHostIsLittleEndian); |
| 83 } |
| 84 Buffer.prototype.getInt32 = function(offset) { |
| 85 return this.dataView.getInt32(offset, kHostIsLittleEndian); |
| 86 } |
| 87 Buffer.prototype.getInt64 = function(offset) { |
| 88 var lo, hi; |
| 89 if (kHostIsLittleEndian) { |
| 90 lo = this.dataView.getUint32(offset, kHostIsLittleEndian); |
| 91 hi = this.dataView.getInt32(offset + 4, kHostIsLittleEndian); |
| 92 } else { |
| 93 hi = this.dataView.getInt32(offset, kHostIsLittleEndian); |
| 94 lo = this.dataView.getUint32(offset + 4, kHostIsLittleEndian); |
| 95 } |
| 96 return lo + hi * kHighWordMultiplier; |
| 97 } |
| 98 |
| 99 Buffer.prototype.getFloat32 = function(offset) { |
| 100 return this.dataView.getFloat32(offset, kHostIsLittleEndian); |
| 101 } |
| 102 Buffer.prototype.getFloat64 = function(offset) { |
| 103 return this.dataView.getFloat64(offset, kHostIsLittleEndian); |
| 104 } |
| 105 |
| 106 Buffer.prototype.setUint8 = function(offset, value) { |
| 107 this.dataView.setUint8(offset, value); |
| 108 } |
| 109 Buffer.prototype.setUint16 = function(offset, value) { |
| 110 this.dataView.setUint16(offset, value, kHostIsLittleEndian); |
| 111 } |
| 112 Buffer.prototype.setUint32 = function(offset, value) { |
| 113 this.dataView.setUint32(offset, value, kHostIsLittleEndian); |
| 114 } |
| 115 Buffer.prototype.setUint64 = function(offset, value) { |
| 116 var hi = (value / kHighWordMultiplier) | 0; |
| 117 if (kHostIsLittleEndian) { |
| 118 this.dataView.setInt32(offset, value, kHostIsLittleEndian); |
| 119 this.dataView.setInt32(offset + 4, hi, kHostIsLittleEndian); |
| 120 } else { |
| 121 this.dataView.setInt32(offset, hi, kHostIsLittleEndian); |
| 122 this.dataView.setInt32(offset + 4, value, kHostIsLittleEndian); |
| 123 } |
| 124 } |
| 125 |
| 126 Buffer.prototype.setInt8 = function(offset, value) { |
| 127 this.dataView.setInt8(offset, value); |
| 128 } |
| 129 Buffer.prototype.setInt16 = function(offset, value) { |
| 130 this.dataView.setInt16(offset, value, kHostIsLittleEndian); |
| 131 } |
| 132 Buffer.prototype.setInt32 = function(offset, value) { |
| 133 this.dataView.setInt32(offset, value, kHostIsLittleEndian); |
| 134 } |
| 135 Buffer.prototype.setInt64 = function(offset, value) { |
| 136 var hi = Math.floor(value / kHighWordMultiplier); |
| 137 if (kHostIsLittleEndian) { |
| 138 this.dataView.setInt32(offset, value, kHostIsLittleEndian); |
| 139 this.dataView.setInt32(offset + 4, hi, kHostIsLittleEndian); |
| 140 } else { |
| 141 this.dataView.setInt32(offset, hi, kHostIsLittleEndian); |
| 142 this.dataView.setInt32(offset + 4, value, kHostIsLittleEndian); |
| 143 } |
| 144 } |
| 145 |
| 146 Buffer.prototype.setFloat32 = function(offset, value) { |
| 147 this.dataView.setFloat32(offset, value, kHostIsLittleEndian); |
| 148 } |
| 149 Buffer.prototype.setFloat64 = function(offset, value) { |
| 150 this.dataView.setFloat64(offset, value, kHostIsLittleEndian); |
| 151 } |
| 152 |
| 153 var exports = {}; |
| 154 exports.Buffer = Buffer; |
| 155 return exports; |
| 156 }); |
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