1 /*
   2  * Copyright (c) 2005, 2006, 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 sun.nio.cs;
  27 
  28 import java.nio.ByteBuffer;
  29 import java.nio.CharBuffer;
  30 import java.nio.charset.Charset;
  31 import java.nio.charset.CoderResult;
  32 import java.nio.charset.CharsetDecoder;
  33 import java.nio.charset.CharsetEncoder;
  34 
  35 class UTF_32Coder {
  36     protected static final int BOM_BIG = 0xFEFF;
  37     protected static final int BOM_LITTLE = 0xFFFE0000;
  38     protected static final int NONE = 0;
  39     protected static final int BIG = 1;
  40     protected static final int LITTLE = 2;
  41 
  42     protected static class Decoder extends CharsetDecoder {
  43         private int currentBO;
  44         private int expectedBO;
  45 
  46         protected Decoder(Charset cs, int bo) {
  47             super(cs, 0.25f, 1.0f);
  48             this.expectedBO = bo;
  49             this.currentBO = NONE;
  50         }
  51 
  52         private int getCP(ByteBuffer src) {
  53             return (currentBO==BIG)
  54               ?(((src.get() & 0xff) << 24) |
  55                 ((src.get() & 0xff) << 16) |
  56                 ((src.get() & 0xff) <<  8) |
  57                 (src.get() & 0xff))
  58               :((src.get() & 0xff) |
  59                 ((src.get() & 0xff) <<  8) |
  60                 ((src.get() & 0xff) << 16) |
  61                 ((src.get() & 0xff) << 24));
  62         }
  63 
  64         protected CoderResult decodeLoop(ByteBuffer src, CharBuffer dst) {
  65             if (src.remaining() < 4)
  66                 return CoderResult.UNDERFLOW;
  67             int mark = src.position();
  68             int cp;
  69             try {
  70                 if (currentBO == NONE) {
  71                     cp = ((src.get() & 0xff) << 24) |
  72                          ((src.get() & 0xff) << 16) |
  73                          ((src.get() & 0xff) <<  8) |
  74                          (src.get() & 0xff);
  75                     if (cp == BOM_BIG && expectedBO != LITTLE) {
  76                         currentBO = BIG;
  77                         mark += 4;
  78                     } else if (cp == BOM_LITTLE && expectedBO != BIG) {
  79                         currentBO = LITTLE;
  80                         mark += 4;
  81                     } else {
  82                         if (expectedBO == NONE)
  83                             currentBO = BIG;
  84                         else
  85                             currentBO = expectedBO;
  86                         src.position(mark);
  87                     }
  88                 }
  89                 while (src.remaining() >= 4) {
  90                     cp = getCP(src);
  91                     if (Character.isBmpCodePoint(cp)) {
  92                         if (!dst.hasRemaining())
  93                             return CoderResult.OVERFLOW;
  94                         mark += 4;
  95                         dst.put((char) cp);
  96                     } else if (Character.isValidCodePoint(cp)) {
  97                         if (dst.remaining() < 2)
  98                             return CoderResult.OVERFLOW;
  99                         mark += 4;
 100                         dst.put(Character.highSurrogate(cp));
 101                         dst.put(Character.lowSurrogate(cp));
 102                     } else {
 103                         return CoderResult.malformedForLength(4);
 104                     }
 105                 }
 106                 return CoderResult.UNDERFLOW;
 107             } finally {
 108                 src.position(mark);
 109             }
 110         }
 111         protected void implReset() {
 112             currentBO = NONE;
 113         }
 114     }
 115 
 116     protected static class Encoder extends CharsetEncoder {
 117         private boolean doBOM = false;
 118         private boolean doneBOM = true;
 119         private int byteOrder;
 120 
 121         protected void put(int cp, ByteBuffer dst) {
 122             if (byteOrder==BIG) {
 123                 dst.put((byte)(cp >> 24));
 124                 dst.put((byte)(cp >> 16));
 125                 dst.put((byte)(cp >> 8));
 126                 dst.put((byte)cp);
 127             } else {
 128                 dst.put((byte)cp);
 129                 dst.put((byte)(cp >>  8));
 130                 dst.put((byte)(cp >> 16));
 131                 dst.put((byte)(cp >> 24));
 132             }
 133         }
 134 
 135         protected Encoder(Charset cs, int byteOrder, boolean doBOM) {
 136             super(cs, 4.0f,
 137                   doBOM?8.0f:4.0f,
 138                   (byteOrder==BIG)?new byte[]{(byte)0, (byte)0, (byte)0xff, (byte)0xfd}
 139                                   :new byte[]{(byte)0xfd, (byte)0xff, (byte)0, (byte)0});
 140             this.byteOrder = byteOrder;
 141             this.doBOM = doBOM;
 142             this.doneBOM = !doBOM;
 143         }
 144 
 145         protected CoderResult encodeLoop(CharBuffer src, ByteBuffer dst) {
 146             int mark = src.position();
 147             if (!doneBOM && src.hasRemaining()) {
 148                 if (dst.remaining() < 4)
 149                     return CoderResult.OVERFLOW;
 150                 put(BOM_BIG, dst);
 151                 doneBOM = true;
 152             }
 153             try {
 154                 while (src.hasRemaining()) {
 155                     char c = src.get();
 156                     if (!Character.isSurrogate(c)) {
 157                         if (dst.remaining() < 4)
 158                             return CoderResult.OVERFLOW;
 159                         mark++;
 160                         put(c, dst);
 161                     } else if (Character.isHighSurrogate(c)) {
 162                         if (!src.hasRemaining())
 163                             return CoderResult.UNDERFLOW;
 164                         char low = src.get();
 165                         if (Character.isLowSurrogate(low)) {
 166                             if (dst.remaining() < 4)
 167                                 return CoderResult.OVERFLOW;
 168                             mark += 2;
 169                             put(Character.toCodePoint(c, low), dst);
 170                         } else {
 171                             return CoderResult.malformedForLength(1);
 172                         }
 173                     } else {
 174                         // assert Character.isLowSurrogate(c);
 175                         return CoderResult.malformedForLength(1);
 176                     }
 177                 }
 178                 return CoderResult.UNDERFLOW;
 179             } finally {
 180                 src.position(mark);
 181             }
 182         }
 183 
 184         protected void implReset() {
 185             doneBOM = !doBOM;
 186         }
 187 
 188     }
 189 }