ojluni/src/main/java/sun/io/CharToByteDBCS_ASCII.java

/*
 * Copyright (c) 1997, 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.io;

import sun.nio.cs.ext.DoubleByte;
import static sun.nio.cs.CharsetMapping.*;

public abstract class CharToByteDBCS_ASCII extends CharToByteConverter
{

    private char highHalfZoneCode;
    private byte[] outputByte = new byte[2];

    private DoubleByte.Encoder enc;

    public CharToByteDBCS_ASCII(DoubleByte.Encoder enc) {
        super();
        this.enc = enc;
    }

    int encodeChar(char c) {
        return enc.encodeChar(c);
    }

    /**
      * flush out any residual data and reset the buffer state
      */
    public int flush(byte [] output, int outStart, int outEnd)
        throws MalformedInputException, ConversionBufferFullException
    {

       if (highHalfZoneCode != 0) {
          reset();
          badInputLength = 0;
          throw new MalformedInputException();
       }

       reset();
       return 0;
    }

    /**
     * Character conversion
     */
    public int convert(char[] input, int inOff, int inEnd,
                       byte[] output, int outOff, int outEnd)
        throws UnknownCharacterException, MalformedInputException,
               ConversionBufferFullException
    {
        char    inputChar;
        int     inputSize;

        byteOff = outOff;
        charOff = inOff;

        while(charOff < inEnd) {
            int   index;
            int   theBytes;
            int   spaceNeeded;

            if (highHalfZoneCode == 0) {
                inputChar = input[charOff];
                inputSize = 1;
            } else {
                inputChar = highHalfZoneCode;
                inputSize = 0;
                highHalfZoneCode = 0;
            }

            // Is this a high surrogate?
            if (Character.isHighSurrogate(inputChar)) {
                // Is this the last character of the input?
                if (charOff + inputSize >= inEnd) {
                    highHalfZoneCode = inputChar;
                    charOff += inputSize;
                    break;
                }

                // Is there a low surrogate following?
                inputChar = input[charOff + inputSize];
                if (Character.isLowSurrogate(inputChar)) {
                    // We have a valid surrogate pair.  Too bad we don't do
                    // surrogates.  Is substitution enabled?
                    if (subMode) {
                        if (subBytes.length == 1) {
                            outputByte[0] = 0x00;
                            outputByte[1] = subBytes[0];
                        }
                        else {
                            outputByte[0] = subBytes[0];
                            outputByte[1] = subBytes[1];
                        }
                        inputSize++;
                    } else {
                        badInputLength = 2;
                        throw new UnknownCharacterException();
                    }
                 } else {
                     // We have a malformed surrogate pair
                     badInputLength = 1;
                     throw new MalformedInputException();
                 }
            }
            // Is this an unaccompanied low surrogate?
            else if (Character.isLowSurrogate(inputChar)) {
                badInputLength = 1;
                throw new MalformedInputException();
            } else {

                // We have a valid character, get the bytes for it
                theBytes = encodeChar(inputChar);
                if (theBytes == UNMAPPABLE_ENCODING) {
                    // if there was no mapping - look for substitution characters
                    if (subMode) {
                        if (subBytes.length == 1) {
                            outputByte[0] = 0x00;
                            outputByte[1] = subBytes[0];
                        } else {
                            outputByte[0] = subBytes[0];
                            outputByte[1] = subBytes[1];
                        }
                    } else {
                        badInputLength = 1;
                        throw new UnknownCharacterException();
                    }
                } else {
                    outputByte[0] = (byte)(theBytes >>8);
                    outputByte[1] = (byte)theBytes;
                }
            }
            if (outputByte[0] == 0x00)
                spaceNeeded = 1;
            else
                spaceNeeded = 2;

            if (byteOff + spaceNeeded > outEnd)
                throw new ConversionBufferFullException();

            if (spaceNeeded == 1)
                output[byteOff++] = outputByte[1];
            else {
                output[byteOff++] = outputByte[0];
                output[byteOff++] = outputByte[1];
            }

            charOff += inputSize;
        }
        return byteOff - outOff;
    }

    /**
     * Resets converter to its initial state.
     */
    public void reset() {
       charOff = byteOff = 0;
       highHalfZoneCode = 0;
    }

    /**
     * Returns the maximum number of bytes needed to convert a char.
     */
    public int getMaxBytesPerChar() {
        return 2;
    }

    /**
     * Returns true if the given character can be converted to the
     * target character encoding.
     */
    public boolean canConvert(char c) {
        return encodeChar(c) != UNMAPPABLE_ENCODING;
    }
}