/*

 * Copyright (c) 2009, 2013, 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.fs;

import java.util.*;

import java.nio.file.*;

import java.nio.charset.Charset;

import java.security.*;

import sun.security.action.*;

/**

 * Utility methods

 */

class Util {

    private Util() { }

    private static final Charset jnuEncoding = Charset.forName(

        AccessController.doPrivileged(new GetPropertyAction("sun.jnu.encoding")));

    /**

     * Returns {@code Charset} corresponding to the sun.jnu.encoding property

     */

    static Charset jnuEncoding() {

        return jnuEncoding;

    }

    /**

     * Encodes the given String into a sequence of bytes using the {@code Charset}

     * specified by the sun.jnu.encoding property.

     */

    static byte[] toBytes(String s) {

        return s.getBytes(jnuEncoding);

    }

    /**

     * Constructs a new String by decoding the specified array of bytes using the

     * {@code Charset} specified by the sun.jnu.encoding property.

     */

    static String toString(byte[] bytes) {

        return new String(bytes, jnuEncoding);

    }

    /**

     * Splits a string around the given character. The array returned by this

     * method contains each substring that is terminated by the character. Use

     * for simple string spilting cases when needing to avoid loading regex.

     */

    static String[] split(String s, char c) {

        int count = 0;

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

            if (s.charAt(i) == c)

                count++;

        }

        String[] result = new String[count+1];

        int n = 0;

        int last = 0;

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

            if (s.charAt(i) == c) {

                result[n++] = s.substring(last, i);

                last = i + 1;

            }

        }

        result[n] = s.substring(last, s.length());

        return result;

    }

    /**

     * Returns a Set containing the given elements.

     */

    @SafeVarargs

    static <E> Set<E> newSet(E... elements) {

        HashSet<E> set = new HashSet<>();

        for (E e: elements) {

            set.add(e);

        }

        return set;

    }

    /**

     * Returns a Set containing all the elements of the given Set plus

     * the given elements.

     */

    @SafeVarargs

    static <E> Set<E> newSet(Set<E> other, E... elements) {

        HashSet<E> set = new HashSet<>(other);

        for (E e: elements) {

            set.add(e);

        }

        return set;

    }

    /**

     * Returns {@code true} if symbolic links should be followed

     */

    static boolean followLinks(LinkOption... options) {

        boolean followLinks = true;

        for (LinkOption option: options) {

            if (option == LinkOption.NOFOLLOW_LINKS) {

                followLinks = false;

            } else if (option == null) {

                throw new NullPointerException();

            } else {

                throw new AssertionError("Should not get here");

            }

        }

        return followLinks;

    }

}