| /** |
| * Copyright (c) 2008-2010 Andrey Somov |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.yaml.snakeyaml.reader; |
| |
| /** |
| version: 1.1 / 2007-01-25 |
| - changed BOM recognition ordering (longer boms first) |
| |
| Original pseudocode : Thomas Weidenfeller |
| Implementation tweaked: Aki Nieminen |
| Implementation changed: Andrey Somov |
| * UTF-32 removed because it is not supported by YAML |
| * no default encoding |
| |
| http://www.unicode.org/unicode/faq/utf_bom.html |
| BOMs: |
| 00 00 FE FF = UTF-32, big-endian |
| FF FE 00 00 = UTF-32, little-endian |
| EF BB BF = UTF-8, |
| FE FF = UTF-16, big-endian |
| FF FE = UTF-16, little-endian |
| |
| Win2k Notepad: |
| Unicode format = UTF-16LE |
| ***/ |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.InputStreamReader; |
| import java.io.PushbackInputStream; |
| |
| /** |
| * Generic unicode textreader, which will use BOM mark to identify the encoding |
| * to be used. If BOM is not found then use a given default or system encoding. |
| */ |
| public class UnicodeReader extends java.io.Reader { |
| PushbackInputStream internalIn; |
| InputStreamReader internalIn2 = null; |
| |
| private static final int BOM_SIZE = 3; |
| |
| /** |
| * |
| * @param in |
| * InputStream to be read |
| * @param defaultEnc |
| * default encoding if stream does not have BOM marker. Give NULL |
| * to use system-level default. |
| */ |
| public UnicodeReader(InputStream in) { |
| internalIn = new PushbackInputStream(in, BOM_SIZE); |
| } |
| |
| /** |
| * Get stream encoding or NULL if stream is uninitialized. Call init() or |
| * read() method to initialize it. |
| */ |
| public String getEncoding() { |
| return internalIn2.getEncoding(); |
| } |
| |
| /** |
| * Read-ahead four bytes and check for BOM marks. Extra bytes are unread |
| * back to the stream, only BOM bytes are skipped. |
| */ |
| protected void init() throws IOException { |
| if (internalIn2 != null) |
| return; |
| |
| String encoding; |
| byte bom[] = new byte[BOM_SIZE]; |
| int n, unread; |
| n = internalIn.read(bom, 0, bom.length); |
| |
| if ((bom[0] == (byte) 0xEF) && (bom[1] == (byte) 0xBB) && (bom[2] == (byte) 0xBF)) { |
| encoding = "UTF-8"; |
| unread = n - 3; |
| } else if ((bom[0] == (byte) 0xFE) && (bom[1] == (byte) 0xFF)) { |
| encoding = "UTF-16BE"; |
| unread = n - 2; |
| } else if ((bom[0] == (byte) 0xFF) && (bom[1] == (byte) 0xFE)) { |
| encoding = "UTF-16LE"; |
| unread = n - 2; |
| } else { |
| // Unicode BOM mark not found, unread all bytes |
| encoding = "UTF-8"; |
| unread = n; |
| } |
| |
| if (unread > 0) |
| internalIn.unread(bom, (n - unread), unread); |
| |
| // Use given encoding |
| internalIn2 = new InputStreamReader(internalIn, encoding); |
| } |
| |
| public void close() throws IOException { |
| init(); |
| internalIn2.close(); |
| } |
| |
| public int read(char[] cbuf, int off, int len) throws IOException { |
| init(); |
| return internalIn2.read(cbuf, off, len); |
| } |
| |
| } |