/*

 * Copyright (c) 2015, 2016, 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.util;

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.nio.charset.StandardCharsets;

import java.util.Objects;

/**

 * A Charset implementation for reading PropertyResourceBundle, in order

 * for loading properties files. This first tries to load the properties

 * file with UTF-8 encoding). If it fails, then load the file with ISO-8859-1

 */

public class PropertyResourceBundleCharset extends Charset {

    private boolean strictUTF8 = false;

    public PropertyResourceBundleCharset(boolean strictUTF8) {

        this(PropertyResourceBundleCharset.class.getCanonicalName(), null);

        this.strictUTF8 = strictUTF8;

    }

    public PropertyResourceBundleCharset(String canonicalName, String[] aliases) {

        super(canonicalName, aliases);

    }

    @Override

    public boolean contains(Charset cs) {

        return false;

    }

    @Override

    public CharsetDecoder newDecoder() {

        return new PropertiesFileDecoder(this, 1.0f, 1.0f);

    }

    @Override

    public CharsetEncoder newEncoder() {

        throw new UnsupportedOperationException("Encoding is not supported");

    }

    private final class PropertiesFileDecoder extends CharsetDecoder {

        private CharsetDecoder cdUTF_8 = StandardCharsets.UTF_8.newDecoder()

                                .onMalformedInput(CodingErrorAction.REPORT)

                                .onUnmappableCharacter(CodingErrorAction.REPORT);

        private CharsetDecoder cdISO_8859_1 = null;

        protected PropertiesFileDecoder(Charset cs,

                float averageCharsPerByte, float maxCharsPerByte) {

            super(cs, averageCharsPerByte, maxCharsPerByte);

        }

        protected CoderResult decodeLoop(ByteBuffer in, CharBuffer out) {

            if (Objects.nonNull(cdISO_8859_1)) {

                return cdISO_8859_1.decode(in, out, false);

            }

            in.mark();

            out.mark();

            CoderResult cr = cdUTF_8.decode(in, out, false);

            if (cr.isUnderflow() || cr.isOverflow() ||

                PropertyResourceBundleCharset.this.strictUTF8) {

                return cr;

            }

            // Invalid or unmappable UTF-8 sequence detected.

            // Switching to the ISO 8859-1 decorder.

            assert cr.isMalformed() || cr.isUnmappable();

            in.reset();

            out.reset();

            cdISO_8859_1 = StandardCharsets.ISO_8859_1.newDecoder();

            return cdISO_8859_1.decode(in, out, false);

        }

    }

}