/*

 * Copyright (c) 2006, 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

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package sun.security.ssl;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

import javax.net.ssl.SSLProtocolException;

final class EllipticPointFormatsExtension extends HelloExtension {

    static final int FMT_UNCOMPRESSED = 0;

    static final int FMT_ANSIX962_COMPRESSED_PRIME = 1;

    static final int FMT_ANSIX962_COMPRESSED_CHAR2 = 2;

    static final HelloExtension DEFAULT =

            new EllipticPointFormatsExtension(new byte[] {FMT_UNCOMPRESSED});

    private final byte[] formats;

    private EllipticPointFormatsExtension(byte[] formats) {

        super(ExtensionType.EXT_EC_POINT_FORMATS);

        this.formats = formats;

    }

    EllipticPointFormatsExtension(HandshakeInStream s, int len)

            throws IOException {

        super(ExtensionType.EXT_EC_POINT_FORMATS);

        formats = s.getBytes8();

        // RFC 4492 says uncompressed points must always be supported.

        // Check just to make sure.

        boolean uncompressed = false;

        for (int format : formats) {

            if (format == FMT_UNCOMPRESSED) {

                uncompressed = true;

                break;

            }

        }

        if (uncompressed == false) {

            throw new SSLProtocolException

                ("Peer does not support uncompressed points");

        }

    }

    @Override

    int length() {

        return 5 + formats.length;

    }

    @Override

    void send(HandshakeOutStream s) throws IOException {

        s.putInt16(type.id);

        s.putInt16(formats.length + 1);

        s.putBytes8(formats);

    }

    private static String toString(byte format) {

        int f = format & 0xff;

        switch (f) {

        case FMT_UNCOMPRESSED:

            return "uncompressed";

        case FMT_ANSIX962_COMPRESSED_PRIME:

            return "ansiX962_compressed_prime";

        case FMT_ANSIX962_COMPRESSED_CHAR2:

            return "ansiX962_compressed_char2";

        default:

            return "unknown-" + f;

        }

    }

    @Override

    public String toString() {

        List<String> list = new ArrayList<String>();

        for (byte format : formats) {

            list.add(toString(format));

        }

        return "Extension " + type + ", formats: " + list;

    }

}