/*

 * Copyright (c) 2008, 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.cs;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.io.BufferedReader;

import java.io.IOException;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import java.util.*;

import java.security.*;

public class CharsetMapping {

    char[] b2cSB;                //singlebyte b->c

    char[] b2cDB1;               //dobulebyte b->c /db1

    char[] b2cDB2;               //dobulebyte b->c /db2

    int    b2Min, b2Max;         //min/max(start/end) value of 2nd byte

    int    b1MinDB1, b1MaxDB1;   //min/Max(start/end) value of 1st byte/db1

    int    b1MinDB2, b1MaxDB2;   //min/Max(start/end) value of 1st byte/db2

    int    dbSegSize;

    char[] c2b;

    char[] c2bIndex;

    // Supplementary

    char[] b2cSupp;

    char[] c2bSupp;

    // Composite

    Entry[] b2cComp;

    Entry[] c2bComp;

    public char decodeSingle(int b) {

        return b2cSB[b];

    }

    public char decodeDouble(int b1, int b2) {

        if (b2 >= b2Min && b2 < b2Max) {

            b2 -= b2Min;

            if (b1 >= b1MinDB1 && b1 <= b1MaxDB1) {

                b1 -= b1MinDB1;

                return b2cDB1[b1 * dbSegSize + b2];

            }

            if (b1 >= b1MinDB2 && b1 <= b1MaxDB2) {

                b1 -= b1MinDB2;

                return b2cDB2[b1 * dbSegSize + b2];

            }

        }

        return UNMAPPABLE_DECODING;

    }

    // for jis0213 all supplementary characters are in 0x2xxxx range,

    // so only the xxxx part is now stored, should actually store the

    // codepoint value instead.

    public char[] decodeSurrogate(int db, char[] cc) {

        int end = b2cSupp.length / 2;

        int i = Arrays.binarySearch(b2cSupp, 0, end, (char)db);

        if (i >= 0) {

            Character.toChars(b2cSupp[end + i] + 0x20000, cc, 0);

            return cc;

        }

        return null;

    }

    public char[] decodeComposite(Entry comp, char[] cc) {

        int i = findBytes(b2cComp, comp);

        if (i >= 0) {

            cc[0] = (char)b2cComp[i].cp;

            cc[1] = (char)b2cComp[i].cp2;

            return cc;

        }

        return null;

    }

    public int encodeChar(char ch) {

        int index = c2bIndex[ch >> 8];

        if (index == 0xffff)

            return UNMAPPABLE_ENCODING;

        return c2b[index + (ch & 0xff)];

    }

    public int encodeSurrogate(char hi, char lo) {

        int cp = Character.toCodePoint(hi, lo);

        if (cp < 0x20000 || cp >= 0x30000)

            return UNMAPPABLE_ENCODING;

        int end = c2bSupp.length / 2;

        int i = Arrays.binarySearch(c2bSupp, 0, end, (char)cp);

        if (i >= 0)

            return c2bSupp[end + i];

        return UNMAPPABLE_ENCODING;

    }

    public boolean isCompositeBase(Entry comp) {

        if (comp.cp <= 0x31f7 && comp.cp >= 0xe6) {

            return (findCP(c2bComp, comp) >= 0);

        }

        return false;

    }

    public int encodeComposite(Entry comp) {

        int i = findComp(c2bComp, comp);

        if (i >= 0)

            return c2bComp[i].bs;

        return UNMAPPABLE_ENCODING;

    }

    // init the CharsetMapping object from the .dat binary file

    public static CharsetMapping get(final InputStream is) {

        return AccessController.doPrivileged(new PrivilegedAction<>() {

            public CharsetMapping run() {

                return new CharsetMapping().load(is);

            }

        });

    }

    public static class Entry {

        public int bs;   //byte sequence reps

        public int cp;   //Unicode codepoint

        public int cp2;  //CC of composite

    }

    static Comparator<Entry> comparatorBytes =

        new Comparator<Entry>() {

            public int compare(Entry m1, Entry m2) {

                return m1.bs - m2.bs;

            }

            public boolean equals(Object obj) {

                return this == obj;

            }

    };

    static Comparator<Entry> comparatorCP =

        new Comparator<Entry>() {

            public int compare(Entry m1, Entry m2) {

                return m1.cp - m2.cp;

            }

            public boolean equals(Object obj) {

                return this == obj;

            }

    };

    static Comparator<Entry> comparatorComp =

        new Comparator<Entry>() {

            public int compare(Entry m1, Entry m2) {

                 int v = m1.cp - m2.cp;

                 if (v == 0)

                   v = m1.cp2 - m2.cp2;

                 return v;

            }

            public boolean equals(Object obj) {

                return this == obj;

            }

    };

    static int findBytes(Entry[] a, Entry k) {

        return Arrays.binarySearch(a, 0, a.length, k, comparatorBytes);

    }

    static int findCP(Entry[] a, Entry k) {

        return Arrays.binarySearch(a, 0, a.length, k, comparatorCP);

    }

    static int findComp(Entry[] a, Entry k) {

        return Arrays.binarySearch(a, 0, a.length, k, comparatorComp);

    }

    /*****************************************************************************/

    // tags of different charset mapping tables

    private static final boolean readNBytes(InputStream in, byte[] bb, int N)

        throws IOException

    {

        int off = 0;

        while (N > 0) {

            int n = in.read(bb, off, N);

            if (n == -1)

                return false;

            N = N - n;

            off += n;

        }

        return true;

    }

    int off = 0;

    byte[] bb;

    private char[] readCharArray() {

        // first 2 bytes are the number of "chars" stored in this table

        int size  = ((bb[off++]&0xff)<<8) | (bb[off++]&0xff);

        char [] cc = new char[size];

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

            cc[i] = (char)(((bb[off++]&0xff)<<8) | (bb[off++]&0xff));

        }

        return cc;

    }

    void readSINGLEBYTE() {

        char[] map = readCharArray();

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

            char c = map[i];

            if (c != UNMAPPABLE_DECODING) {

                c2b[c2bIndex[c >> 8] + (c&0xff)] = (char)i;

            }

        }

        b2cSB = map;

    }

    void readINDEXC2B() {

        char[] map = readCharArray();

        for (int i = map.length - 1; i >= 0; i--) {

            if (c2b == null && map[i] != -1) {

                c2b = new char[map[i] + 256];

                Arrays.fill(c2b, (char)UNMAPPABLE_ENCODING);

                break;

            }

        }

        c2bIndex = map;

    }

    char[] readDB(int b1Min, int b2Min, int segSize) {

        char[] map = readCharArray();

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

            char c = map[i];

            if (c != UNMAPPABLE_DECODING) {

                int b1 = i / segSize;

                int b2 = i % segSize;

                int b = (b1 + b1Min)* 256 + (b2 + b2Min);

                //System.out.printf("    DB %x\t%x%n", b, c & 0xffff);

                c2b[c2bIndex[c >> 8] + (c&0xff)] = (char)(b);

            }

        }

        return map;

    }

    void readDOUBLEBYTE1() {

        b1MinDB1 = ((bb[off++]&0xff)<<8) | (bb[off++]&0xff);

        b1MaxDB1 = ((bb[off++]&0xff)<<8) | (bb[off++]&0xff);

        b2Min =    ((bb[off++]&0xff)<<8) | (bb[off++]&0xff);

        b2Max =    ((bb[off++]&0xff)<<8) | (bb[off++]&0xff);

        dbSegSize = b2Max - b2Min + 1;

        b2cDB1 = readDB(b1MinDB1, b2Min, dbSegSize);

    }

    void readDOUBLEBYTE2() {

        b1MinDB2 = ((bb[off++]&0xff)<<8) | (bb[off++]&0xff);

        b1MaxDB2 = ((bb[off++]&0xff)<<8) | (bb[off++]&0xff);

        b2Min =    ((bb[off++]&0xff)<<8) | (bb[off++]&0xff);

        b2Max =    ((bb[off++]&0xff)<<8) | (bb[off++]&0xff);

        dbSegSize = b2Max - b2Min + 1;

        b2cDB2 = readDB(b1MinDB2, b2Min, dbSegSize);

    }

    void readCOMPOSITE() {

        char[] map = readCharArray();

        int mLen = map.length/3;

        b2cComp = new Entry[mLen];

        c2bComp = new Entry[mLen];

        for (int i = 0, j= 0; i < mLen; i++) {

            Entry m = new Entry();

            m.bs = map[j++];

            m.cp = map[j++];

            m.cp2 = map[j++];

            b2cComp[i] = m;

            c2bComp[i] = m;

        }

        Arrays.sort(c2bComp, 0, c2bComp.length, comparatorComp);

    }

    CharsetMapping load(InputStream in) {

        try {

            // The first 4 bytes are the size of the total data followed in

            // this .dat file.

            int len = ((in.read()&0xff) << 24) | ((in.read()&0xff) << 16) |

                      ((in.read()&0xff) << 8) | (in.read()&0xff);

            bb = new byte[len];

            off = 0;

            //System.out.printf("In : Total=%d%n", len);

            // Read in all bytes

            if (!readNBytes(in, bb, len))

                throw new RuntimeException("Corrupted data file");

            in.close();

            while (off < len) {

                int type = ((bb[off++]&0xff)<<8) | (bb[off++]&0xff);

                switch(type) {

                case MAP_INDEXC2B:

                    readINDEXC2B();

                    break;

                case MAP_SINGLEBYTE:

                    readSINGLEBYTE();

                    break;

                case MAP_DOUBLEBYTE1:

                    readDOUBLEBYTE1();

                    break;

                case MAP_DOUBLEBYTE2:

                    readDOUBLEBYTE2();

                    break;

                case MAP_SUPPLEMENT:

                    b2cSupp = readCharArray();

                    break;

                case MAP_SUPPLEMENT_C2B:

                    c2bSupp = readCharArray();

                    break;

                case MAP_COMPOSITE:

                    readCOMPOSITE();

                    break;

                default:

                    throw new RuntimeException("Corrupted data file");

                }

            }

            bb = null;

            return this;

        } catch (IOException x) {

            x.printStackTrace();

            return null;

        }

    }

}