/*

 * Copyright (c) 1999, 2012, 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 com.sun.tools.javac.util;

/** An abstraction for internal compiler strings. They are stored in

 *  Utf8 format. Names are stored in a Name.Table, and are unique within

 *  that table.

 *

 *  <p><b>This is NOT part of any supported API.

 *  If you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 */

public abstract class Name implements javax.lang.model.element.Name {

    public final Table table;

    protected Name(Table table) {

        this.table = table;

    }

    /**

     * {@inheritDoc}

     */

    public boolean contentEquals(CharSequence cs) {

        return toString().equals(cs.toString());

    }

    /**

     * {@inheritDoc}

     */

    public int length() {

        return toString().length();

    }

    /**

     * {@inheritDoc}

     */

    public char charAt(int index) {

        return toString().charAt(index);

    }

    /**

     * {@inheritDoc}

     */

    public CharSequence subSequence(int start, int end) {

        return toString().subSequence(start, end);

    }

    /** Return the concatenation of this name and name `n'.

     */

    public Name append(Name n) {

        int len = getByteLength();

        byte[] bs = new byte[len + n.getByteLength()];

        getBytes(bs, 0);

        n.getBytes(bs, len);

        return table.fromUtf(bs, 0, bs.length);

    }

    /** Return the concatenation of this name, the given ASCII

     *  character, and name `n'.

     */

    public Name append(char c, Name n) {

        int len = getByteLength();

        byte[] bs = new byte[len + 1 + n.getByteLength()];

        getBytes(bs, 0);

        bs[len] = (byte) c;

        n.getBytes(bs, len+1);

        return table.fromUtf(bs, 0, bs.length);

    }

    /** An arbitrary but consistent complete order among all Names.

     */

    public int compareTo(Name other) {

        return other.getIndex() - this.getIndex();

    }

    /** Return true if this is the empty name.

     */

    public boolean isEmpty() {

        return getByteLength() == 0;

    }

    /** Returns last occurrence of byte b in this name, -1 if not found.

     */

    public int lastIndexOf(byte b) {

        byte[] bytes = getByteArray();

        int offset = getByteOffset();

        int i = getByteLength() - 1;

        while (i >= 0 && bytes[offset + i] != b) i--;

        return i;

    }

    /** Does this name start with prefix?

     */

    public boolean startsWith(Name prefix) {

        byte[] thisBytes = this.getByteArray();

        int thisOffset   = this.getByteOffset();

        int thisLength   = this.getByteLength();

        byte[] prefixBytes = prefix.getByteArray();

        int prefixOffset   = prefix.getByteOffset();

        int prefixLength   = prefix.getByteLength();

        int i = 0;

        while (i < prefixLength &&

               i < thisLength &&

               thisBytes[thisOffset + i] == prefixBytes[prefixOffset + i])

            i++;

        return i == prefixLength;

    }

    /** Returns the sub-name starting at position start, up to and

     *  excluding position end.

     */

    public Name subName(int start, int end) {

        if (end < start) end = start;

        return table.fromUtf(getByteArray(), getByteOffset() + start, end - start);

    }

    /** Return the string representation of this name.

     */

    @Override

    public String toString() {

        return Convert.utf2string(getByteArray(), getByteOffset(), getByteLength());

    }

    /** Return the Utf8 representation of this name.

     */

    public byte[] toUtf() {

        byte[] bs = new byte[getByteLength()];

        getBytes(bs, 0);

        return bs;

    }

    /* Get a "reasonably small" value that uniquely identifies this name

     * within its name table.

     */

    public abstract int getIndex();

    /** Get the length (in bytes) of this name.

     */

    public abstract int getByteLength();

    /** Returns i'th byte of this name.

     */

    public abstract byte getByteAt(int i);

    /** Copy all bytes of this name to buffer cs, starting at start.

     */

    public void getBytes(byte cs[], int start) {

        System.arraycopy(getByteArray(), getByteOffset(), cs, start, getByteLength());

    }

    /** Get the underlying byte array for this name. The contents of the

     * array must not be modified.

     */

    public abstract byte[] getByteArray();

    /** Get the start offset of this name within its byte array.

     */

    public abstract int getByteOffset();

    /** An abstraction for the hash table used to create unique Name instances.

     */

    public static abstract class Table {

        /** Standard name table.

         */

        public final Names names;

        Table(Names names) {

            this.names = names;

        }

        /** Get the name from the characters in cs[start..start+len-1].

         */

        public abstract Name fromChars(char[] cs, int start, int len);

        /** Get the name for the characters in string s.

         */

        public Name fromString(String s) {

            char[] cs = s.toCharArray();

            return fromChars(cs, 0, cs.length);

        }

        /** Get the name for the bytes in array cs.

         *  Assume that bytes are in utf8 format.

         */

        public Name fromUtf(byte[] cs) {

            return fromUtf(cs, 0, cs.length);

        }

        /** get the name for the bytes in cs[start..start+len-1].

         *  Assume that bytes are in utf8 format.

         */

        public abstract Name fromUtf(byte[] cs, int start, int len);

        /** Release any resources used by this table.

         */

        public abstract void dispose();

        /** The hashcode of a name.

         */

        protected static int hashValue(byte bytes[], int offset, int length) {

            int h = 0;

            int off = offset;

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

                h = (h << 5) - h + bytes[off++];

            }

            return h;

        }

        /** Compare two subarrays

         */

        protected static boolean equals(byte[] bytes1, int offset1,

                byte[] bytes2, int offset2, int length) {

            int i = 0;

            while (i < length && bytes1[offset1 + i] == bytes2[offset2 + i]) {

                i++;

            }

            return i == length;

        }

    }

}