| // Copyright 2014 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| /** |
| * Defines functions for translating between JavaScript strings and UTF8 strings |
| * stored in ArrayBuffers. There is much room for optimization in this code if |
| * it proves necessary. |
| */ |
| (function() { |
| var internal = mojo.internal; |
| var textDecoder = new TextDecoder('utf-8'); |
| var textEncoder = new TextEncoder('utf-8'); |
| |
| /** |
| * Decodes the UTF8 string from the given buffer. |
| * @param {ArrayBufferView} buffer The buffer containing UTF8 string data. |
| * @return {string} The corresponding JavaScript string. |
| */ |
| function decodeUtf8String(buffer) { |
| return textDecoder.decode(buffer); |
| } |
| |
| /** |
| * Encodes the given JavaScript string into UTF8. |
| * @param {string} str The string to encode. |
| * @param {ArrayBufferView} outputBuffer The buffer to contain the result. |
| * Should be pre-allocated to hold enough space. Use |utf8Length| to determine |
| * how much space is required. |
| * @return {number} The number of bytes written to |outputBuffer|. |
| */ |
| function encodeUtf8String(str, outputBuffer) { |
| const utf8Buffer = textEncoder.encode(str); |
| if (outputBuffer.length < utf8Buffer.length) |
| throw new Error("Buffer too small for encodeUtf8String"); |
| outputBuffer.set(utf8Buffer); |
| return utf8Buffer.length; |
| } |
| |
| /** |
| * Returns the number of bytes that a UTF8 encoding of the JavaScript string |
| * |str| would occupy. |
| */ |
| function utf8Length(str) { |
| return textEncoder.encode(str).length; |
| } |
| |
| internal.decodeUtf8String = decodeUtf8String; |
| internal.encodeUtf8String = encodeUtf8String; |
| internal.utf8Length = utf8Length; |
| })(); |