1/* 2 * Copyright (c) 2014, 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. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23package util; 24 25import java.io.BufferedInputStream; 26import java.io.ByteArrayInputStream; 27import java.io.IOException; 28import java.io.InputStream; 29import java.io.InputStreamReader; 30import java.io.UnsupportedEncodingException; 31import java.util.HashMap; 32import java.util.Map; 33 34public class BOMInputStream { 35 public static InputStream createStream(String charset, InputStream input) { 36 37 try { 38 byte[] content = read(input).getBytes(charset); 39 byte[] head = bom.get(charset); 40 if (head == null) 41 return null; 42 byte[] result = new byte[head.length + content.length]; 43 System.arraycopy(head, 0, result, 0, head.length); 44 System.arraycopy(content, 0, result, head.length, content.length); 45 return new ByteArrayInputStream(result); 46 } catch (UnsupportedEncodingException e) { 47 return null; 48 } 49 } 50 51 private static String read(InputStream input) 52 { 53 try { 54 StringBuffer sb = new StringBuffer(); 55 InputStreamReader r = new InputStreamReader(new BufferedInputStream(input)); 56 int c = 0; 57 while ((c = r.read()) != -1) 58 sb.append((char)c); 59 return sb.toString(); 60 } catch (IOException e) { 61 return ""; 62 } finally { 63 try { 64 input.close(); 65 } catch (IOException e) 66 {} 67 } 68 } 69 70 71 private final static Map<String, byte[]> bom = new HashMap(); 72 private final static byte[][] bomBytes = {{(byte)0xEF, (byte)0xBB, (byte)0xBF}, 73 {(byte)0xFE, (byte)0xFF}}; 74 75 static { 76 bom.put("UTF-8", bomBytes[0]); 77 bom.put("UTF-16BE", bomBytes[1]); 78 } 79 80} 81