/*

 * Copyright (c) 2009, 2017, 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

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package jdk.nio.zipfs;

import java.nio.ByteBuffer;

import java.nio.CharBuffer;

import java.nio.charset.Charset;

import java.nio.charset.CharsetDecoder;

import java.nio.charset.CharsetEncoder;

import java.nio.charset.CoderResult;

import java.nio.charset.CodingErrorAction;

import java.util.Arrays;

import static java.nio.charset.StandardCharsets.UTF_8;

import static java.nio.charset.StandardCharsets.ISO_8859_1;

/**

 * Utility class for zipfile name and comment decoding and encoding

 *

 * @author  Xueming Shen

 */

class ZipCoder {

    static class UTF8 extends ZipCoder {

        UTF8() {

            super(UTF_8);

        }

        @Override

        byte[] getBytes(String s) {        // fast pass for ascii

            for (int i = 0; i < s.length(); i++) {

                if (s.charAt(i) > 0x7f) return super.getBytes(s);

            }

            return s.getBytes(ISO_8859_1);

        }

        @Override

        String toString(byte[] ba) {

            for (byte b : ba) {

                if (b < 0) return super.toString(ba);

            }

            return new String(ba, ISO_8859_1);

        }

    }

    private static final ZipCoder utf8 = new UTF8();

    public static ZipCoder get(String csn) {

        Charset cs = Charset.forName(csn);

        if (cs.name().equals("UTF-8")) {

            return utf8;

        }

        return new ZipCoder(cs);

    }

    String toString(byte[] ba) {

        CharsetDecoder cd = decoder().reset();

        int clen = (int)(ba.length * cd.maxCharsPerByte());

        char[] ca = new char[clen];

        if (clen == 0)

            return new String(ca);

        ByteBuffer bb = ByteBuffer.wrap(ba, 0, ba.length);

        CharBuffer cb = CharBuffer.wrap(ca);

        CoderResult cr = cd.decode(bb, cb, true);

        if (!cr.isUnderflow())

            throw new IllegalArgumentException(cr.toString());

        cr = cd.flush(cb);

        if (!cr.isUnderflow())

            throw new IllegalArgumentException(cr.toString());

        return new String(ca, 0, cb.position());

    }

    byte[] getBytes(String s) {

        CharsetEncoder ce = encoder().reset();

        char[] ca = s.toCharArray();

        int len = (int)(ca.length * ce.maxBytesPerChar());

        byte[] ba = new byte[len];

        if (len == 0)

            return ba;

        ByteBuffer bb = ByteBuffer.wrap(ba);

        CharBuffer cb = CharBuffer.wrap(ca);

        CoderResult cr = ce.encode(cb, bb, true);

        if (!cr.isUnderflow())

            throw new IllegalArgumentException(cr.toString());

        cr = ce.flush(bb);

        if (!cr.isUnderflow())

            throw new IllegalArgumentException(cr.toString());

        if (bb.position() == ba.length)  // defensive copy?

            return ba;

        else

            return Arrays.copyOf(ba, bb.position());

    }

    boolean isUTF8() {

        return cs == UTF_8;

    }

    private Charset cs;

    private ZipCoder(Charset cs) {

        this.cs = cs;

    }

    private final ThreadLocal<CharsetDecoder> decTL = new ThreadLocal<>();

    private final ThreadLocal<CharsetEncoder> encTL = new ThreadLocal<>();

    private CharsetDecoder decoder() {

        CharsetDecoder dec = decTL.get();

        if (dec == null) {

        dec = cs.newDecoder()

            .onMalformedInput(CodingErrorAction.REPORT)

            .onUnmappableCharacter(CodingErrorAction.REPORT);

        decTL.set(dec);

        }

        return dec;

    }

    private CharsetEncoder encoder() {

        CharsetEncoder enc = encTL.get();

        if (enc == null) {

        enc = cs.newEncoder()

            .onMalformedInput(CodingErrorAction.REPORT)

            .onUnmappableCharacter(CodingErrorAction.REPORT);

        encTL.set(enc);

        }

        return enc;

    }

}