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/* * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package sun.nio.cs; import java.nio.ByteBuffer;import java.nio.CharBuffer;import java.nio.charset.Charset;import java.nio.charset.CoderResult;import java.nio.charset.CharsetDecoder;import java.nio.charset.CharsetEncoder; class UTF_32Coder {    protected static final int BOM_BIG = 0xFEFF;    protected static final int BOM_LITTLE = 0xFFFE0000;    protected static final int NONE = 0;    protected static final int BIG = 1;    protected static final int LITTLE = 2;     protected static class Decoder extends CharsetDecoder {        private int currentBO;        private int expectedBO;         protected Decoder(Charset cs, int bo) {            super(cs, 0.25f, 1.0f);            this.expectedBO = bo;            this.currentBO = NONE;        }         private int getCP(ByteBuffer src) {            return (currentBO==BIG)              ?(((src.get() & 0xff) << 24) |                ((src.get() & 0xff) << 16) |                ((src.get() & 0xff) <<  8) |                (src.get() & 0xff))              :((src.get() & 0xff) |                ((src.get() & 0xff) <<  8) |                ((src.get() & 0xff) << 16) |                ((src.get() & 0xff) << 24));        }         protected CoderResult decodeLoop(ByteBuffer src, CharBuffer dst) {            if (src.remaining() < 4)                return CoderResult.UNDERFLOW;            int mark = src.position();            int cp;            try {                if (currentBO == NONE) {                    cp = ((src.get() & 0xff) << 24) |                         ((src.get() & 0xff) << 16) |                         ((src.get() & 0xff) <<  8) |                         (src.get() & 0xff);                    if (cp == BOM_BIG && expectedBO != LITTLE) {                        currentBO = BIG;                        mark += 4;                    } else if (cp == BOM_LITTLE && expectedBO != BIG) {                        currentBO = LITTLE;                        mark += 4;                    } else {                        if (expectedBO == NONE)                            currentBO = BIG;                        else                            currentBO = expectedBO;                        src.position(mark);                    }                }                while (src.remaining() >= 4) {                    cp = getCP(src);                    if (Character.isBmpCodePoint(cp)) {                        if (!dst.hasRemaining())                            return CoderResult.OVERFLOW;                        mark += 4;                        dst.put((char) cp);                    } else if (Character.isValidCodePoint(cp)) {                        if (dst.remaining() < 2)                            return CoderResult.OVERFLOW;                        mark += 4;                        dst.put(Character.highSurrogate(cp));                        dst.put(Character.lowSurrogate(cp));                    } else {                        return CoderResult.malformedForLength(4);                    }                }                return CoderResult.UNDERFLOW;            } finally {                src.position(mark);            }        }        protected void implReset() {            currentBO = NONE;        }    }     protected static class Encoder extends CharsetEncoder {        private boolean doBOM = false;        private boolean doneBOM = true;        private int byteOrder;         protected void put(int cp, ByteBuffer dst) {            if (byteOrder==BIG) {                dst.put((byte)(cp >> 24));                dst.put((byte)(cp >> 16));                dst.put((byte)(cp >> 8));                dst.put((byte)cp);            } else {                dst.put((byte)cp);                dst.put((byte)(cp >>  8));                dst.put((byte)(cp >> 16));                dst.put((byte)(cp >> 24));            }        }         protected Encoder(Charset cs, int byteOrder, boolean doBOM) {            super(cs, 4.0f,                  doBOM?8.0f:4.0f,                  (byteOrder==BIG)?new byte[]{(byte)0, (byte)0, (byte)0xff, (byte)0xfd}                                  :new byte[]{(byte)0xfd, (byte)0xff, (byte)0, (byte)0});            this.byteOrder = byteOrder;            this.doBOM = doBOM;            this.doneBOM = !doBOM;        }         protected CoderResult encodeLoop(CharBuffer src, ByteBuffer dst) {            int mark = src.position();            if (!doneBOM && src.hasRemaining()) {                if (dst.remaining() < 4)                    return CoderResult.OVERFLOW;                put(BOM_BIG, dst);                doneBOM = true;            }            try {                while (src.hasRemaining()) {                    char c = src.get();                    if (!Character.isSurrogate(c)) {                        if (dst.remaining() < 4)                            return CoderResult.OVERFLOW;                        mark++;                        put(c, dst);                    } else if (Character.isHighSurrogate(c)) {                        if (!src.hasRemaining())                            return CoderResult.UNDERFLOW;                        char low = src.get();                        if (Character.isLowSurrogate(low)) {                            if (dst.remaining() < 4)                                return CoderResult.OVERFLOW;                            mark += 2;                            put(Character.toCodePoint(c, low), dst);                        } else {                            return CoderResult.malformedForLength(1);                        }                    } else {                        // assert Character.isLowSurrogate(c);                        return CoderResult.malformedForLength(1);                    }                }                return CoderResult.UNDERFLOW;            } finally {                src.position(mark);            }        }         protected void implReset() {            doneBOM = !doBOM;        }     }}