/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.cellbroadcastservice;

import android.util.Log;
import android.util.SparseIntArray;

/**
 * This class implements the character set mapping between
 * the GSM SMS 7-bit alphabet specified in TS 23.038 6.2.1
 * and UTF-16
 *
 * {@hide}
 */
public class GsmAlphabet {
    private static final String TAG = "GSM";

    private GsmAlphabet() {
    }

    /**
     * This escapes extended characters, and when present indicates that the
     * following character should be looked up in the "extended" table.
     *
     * gsmToChar(GSM_EXTENDED_ESCAPE) returns 0xffff
     */
    public static final byte GSM_EXTENDED_ESCAPE = 0x1B;

    /**
     * User data header requires one octet for length. Count as one septet, because
     * all combinations of header elements below will have at least one free bit
     * when padding to the nearest septet boundary.
     */
    public static final int UDH_SEPTET_COST_LENGTH = 1;

    /**
     * Using a non-default language locking shift table OR single shift table
     * requires a user data header of 3 octets, or 4 septets, plus UDH length.
     */
    public static final int UDH_SEPTET_COST_ONE_SHIFT_TABLE = 4;

    /**
     * Using a non-default language locking shift table AND single shift table
     * requires a user data header of 6 octets, or 7 septets, plus UDH length.
     */
    public static final int UDH_SEPTET_COST_TWO_SHIFT_TABLES = 7;

    /**
     * Multi-part messages require a user data header of 5 octets, or 6 septets,
     * plus UDH length.
     */
    public static final int UDH_SEPTET_COST_CONCATENATED_MESSAGE = 6;

    /** Reverse mapping from Unicode characters to indexes into language tables. */
    private static SparseIntArray[] sCharsToGsmTables;

    /** Reverse mapping from Unicode characters to indexes into language shift tables. */
    private static SparseIntArray[] sCharsToShiftTables;

    /**
     * GSM default 7 bit alphabet plus national language locking shift character tables.
     * Comment lines above strings indicate the lower four bits of the table position.
     */
    private static final String[] sLanguageTables = {
            /* 3GPP TS 23.038 V9.1.1 section 6.2.1 - GSM 7 bit Default Alphabet
             01.....23.....4.....5.....6.....7.....8.....9.....A.B.....C.....D.E.....F.....0....
             .1 */
            "@\u00a3$\u00a5\u00e8\u00e9\u00f9\u00ec\u00f2\u00c7\n\u00d8\u00f8\r\u00c5\u00e5\u0394_"
                    // 2.....3.....4.....5.....6.....7.....8.....9.....A.....B.....C.....D.....E.
                    // ....
                    + "\u03a6\u0393\u039b\u03a9\u03a0\u03a8\u03a3\u0398\u039e\uffff\u00c6\u00e6"
                    + "\u00df"
                    // F.....012.34.....56789ABCDEF0123456789ABCDEF0.....123456789ABCDEF0123456789A
                    + "\u00c9 !\"#\u00a4%&'()*+,-./0123456789:;<=>?\u00a1ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                    // B.....C.....D.....E.....F.....0.....123456789ABCDEF0123456789AB.....C....
                    // .D.....
                    + "\u00c4\u00d6\u00d1\u00dc\u00a7\u00bfabcdefghijklmnopqrstuvwxyz\u00e4\u00f6"
                    + "\u00f1"
                    // E.....F.....
                    + "\u00fc\u00e0",

            /* A.3.1 Turkish National Language Locking Shift Table
             01.....23.....4.....5.....6.....7.....8.....9.....A.B.....C.....D.E.....F.....0....
             .1 */
            "@\u00a3$\u00a5\u20ac\u00e9\u00f9\u0131\u00f2\u00c7\n\u011e\u011f\r\u00c5\u00e5\u0394_"
                    // 2.....3.....4.....5.....6.....7.....8.....9.....A.....B.....C.....D.....E.
                    // ....
                    + "\u03a6\u0393\u039b\u03a9\u03a0\u03a8\u03a3\u0398\u039e\uffff\u015e\u015f"
                    + "\u00df"
                    // F.....012.34.....56789ABCDEF0123456789ABCDEF0.....123456789ABCDEF0123456789A
                    + "\u00c9 !\"#\u00a4%&'()*+,-./0123456789:;<=>?\u0130ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                    // B.....C.....D.....E.....F.....0.....123456789ABCDEF0123456789AB.....C....
                    // .D.....
                    + "\u00c4\u00d6\u00d1\u00dc\u00a7\u00e7abcdefghijklmnopqrstuvwxyz\u00e4\u00f6"
                    + "\u00f1"
                    // E.....F.....
                    + "\u00fc\u00e0",

            /* A.3.2 Void (no locking shift table for Spanish) */
            "",

            /* A.3.3 Portuguese National Language Locking Shift Table
             01.....23.....4.....5.....6.....7.....8.....9.....A.B.....C.....D.E.....F.....0....
             .1 */
            "@\u00a3$\u00a5\u00ea\u00e9\u00fa\u00ed\u00f3\u00e7\n\u00d4\u00f4\r\u00c1\u00e1\u0394_"
                    // 2.....3.....4.....5.....67.8.....9.....AB.....C.....D.....E.....F.....012
                    // .34.....
                    + "\u00aa\u00c7\u00c0\u221e^\\\u20ac\u00d3|\uffff\u00c2\u00e2\u00ca\u00c9 "
                    + "!\"#\u00ba"
                    // 56789ABCDEF0123456789ABCDEF0.....123456789ABCDEF0123456789AB.....C.....D..
                    // ...E.....
                    + "%&'()*+,-./0123456789:;<=>?\u00cdABCDEFGHIJKLMNOPQRSTUVWXYZ\u00c3\u00d5"
                    + "\u00da\u00dc"
                    // F.....0123456789ABCDEF0123456789AB.....C.....DE.....F.....
                    + "\u00a7~abcdefghijklmnopqrstuvwxyz\u00e3\u00f5`\u00fc\u00e0",

            /* A.3.4 Bengali National Language Locking Shift Table
             0.....1.....2.....3.....4.....5.....6.....7.....8.....9.....A.B.....CD.EF.....0..... */
            "\u0981\u0982\u0983\u0985\u0986\u0987\u0988\u0989\u098a\u098b\n\u098c \r \u098f\u0990"
                    // 123.....4.....5.....6.....7.....8.....9.....A.....B.....C.....D.....E....
                    // .F.....
                    + "  \u0993\u0994\u0995\u0996\u0997\u0998\u0999\u099a\uffff\u099b\u099c\u099d"
                    + "\u099e"
                    // 012.....3.....4.....5.....6.....7.....89A.....B.....CD.....EF....
                    // .0123456789ABC
                    + " !\u099f\u09a0\u09a1\u09a2\u09a3\u09a4)(\u09a5\u09a6,\u09a7"
                    + ".\u09a80123456789:; "
                    // D.....E.....F0.....1.....2.....3.....4.....56.....789A.....B.....C.....D.....
                    + "\u09aa\u09ab?\u09ac\u09ad\u09ae\u09af\u09b0 \u09b2   "
                    + "\u09b6\u09b7\u09b8\u09b9"
                    // E.....F.....0.....1.....2.....3.....4.....5.....6.....789.....A.....BCD...
                    // ..E.....
                    + "\u09bc\u09bd\u09be\u09bf\u09c0\u09c1\u09c2\u09c3\u09c4  \u09c7\u09c8  "
                    + "\u09cb\u09cc"
                    // F.....0.....123456789ABCDEF0123456789AB.....C.....D.....E.....F.....
                    + "\u09cd\u09ceabcdefghijklmnopqrstuvwxyz\u09d7\u09dc\u09dd\u09f0\u09f1",

            /* A.3.5 Gujarati National Language Locking Shift Table
             0.....1.....2.....3.....4.....5.....6.....7.....8.....9.....A.B.....C.....D.EF.....0
             .....*/
            "\u0a81\u0a82\u0a83\u0a85\u0a86\u0a87\u0a88\u0a89\u0a8a\u0a8b\n\u0a8c\u0a8d\r "
                    + "\u0a8f\u0a90"
                    // 1.....23.....4.....5.....6.....7.....8.....9.....A.....B.....C.....D.....E
                    // .....
                    + "\u0a91 \u0a93\u0a94\u0a95\u0a96\u0a97\u0a98\u0a99\u0a9a\uffff\u0a9b\u0a9c"
                    + "\u0a9d"
                    // F.....012.....3.....4.....5.....6.....7.....89A.....B.....CD.....EF....
                    // .0123456789AB
                    + "\u0a9e !\u0a9f\u0aa0\u0aa1\u0aa2\u0aa3\u0aa4)(\u0aa5\u0aa6,\u0aa7"
                    + ".\u0aa80123456789:;"
                    // CD.....E.....F0.....1.....2.....3.....4.....56.....7.....89.....A.....B...
                    // ..C.....
                    + " \u0aaa\u0aab?\u0aac\u0aad\u0aae\u0aaf\u0ab0 \u0ab2\u0ab3 "
                    + "\u0ab5\u0ab6\u0ab7\u0ab8"
                    // D.....E.....F.....0.....1.....2.....3.....4.....5.....6.....7.....89.....A
                    // .....
                    + "\u0ab9\u0abc\u0abd\u0abe\u0abf\u0ac0\u0ac1\u0ac2\u0ac3\u0ac4\u0ac5 "
                    + "\u0ac7\u0ac8"
                    // B.....CD.....E.....F.....0.....123456789ABCDEF0123456789AB.....C.....D....
                    // .E.....
                    + "\u0ac9 \u0acb\u0acc\u0acd\u0ad0abcdefghijklmnopqrstuvwxyz\u0ae0\u0ae1"
                    + "\u0ae2\u0ae3"
                    // F.....
                    + "\u0af1",

            /* A.3.6 Hindi National Language Locking Shift Table
             0.....1.....2.....3.....4.....5.....6.....7.....8.....9.....A.B.....C.....D.E.....F.
             ....*/
            "\u0901\u0902\u0903\u0905\u0906\u0907\u0908\u0909\u090a\u090b\n\u090c\u090d\r\u090e"
                    + "\u090f"
                    // 0.....1.....2.....3.....4.....5.....6.....7.....8.....9.....A.....B.....C.
                    // ....D.....
                    + "\u0910\u0911\u0912\u0913\u0914\u0915\u0916\u0917\u0918\u0919\u091a\uffff"
                    + "\u091b\u091c"
                    // E.....F.....012.....3.....4.....5.....6.....7.....89A.....B.....CD.....EF.
                    // ....012345
                    + "\u091d\u091e !\u091f\u0920\u0921\u0922\u0923\u0924)(\u0925\u0926,\u0927"
                    + ".\u0928012345"
                    // 6789ABC.....D.....E.....F0.....1.....2.....3.....4.....5.....6.....7.....8
                    // .....
                    + "6789:;\u0929\u092a\u092b?\u092c\u092d\u092e\u092f\u0930\u0931\u0932\u0933"
                    + "\u0934"
                    // 9.....A.....B.....C.....D.....E.....F.....0.....1.....2.....3.....4.....5.
                    // ....6.....
                    + "\u0935\u0936\u0937\u0938\u0939\u093c\u093d\u093e\u093f\u0940\u0941\u0942"
                    + "\u0943\u0944"
                    // 7.....8.....9.....A.....B.....C.....D.....E.....F.....0....
                    // .123456789ABCDEF012345678
                    + "\u0945\u0946\u0947\u0948\u0949\u094a\u094b\u094c\u094d"
                    + "\u0950abcdefghijklmnopqrstuvwx"
                    // 9AB.....C.....D.....E.....F.....
                    + "yz\u0972\u097b\u097c\u097e\u097f",

            /* A.3.7 Kannada National Language Locking Shift Table
               NOTE: TS 23.038 V9.1.1 shows code 0x24 as \u0caa, corrected to \u0ca1 (typo)
             01.....2.....3.....4.....5.....6.....7.....8.....9.....A.B.....CD.E.....F.....0....
             .1 */
            " \u0c82\u0c83\u0c85\u0c86\u0c87\u0c88\u0c89\u0c8a\u0c8b\n\u0c8c \r\u0c8e\u0c8f\u0c90 "
                    // 2.....3.....4.....5.....6.....7.....8.....9.....A.....B.....C.....D.....E.
                    // ....F.....
                    + "\u0c92\u0c93\u0c94\u0c95\u0c96\u0c97\u0c98\u0c99\u0c9a\uffff\u0c9b\u0c9c"
                    + "\u0c9d\u0c9e"
                    // 012.....3.....4.....5.....6.....7.....89A.....B.....CD.....EF....
                    // .0123456789ABC
                    + " !\u0c9f\u0ca0\u0ca1\u0ca2\u0ca3\u0ca4)(\u0ca5\u0ca6,\u0ca7"
                    + ".\u0ca80123456789:; "
                    // D.....E.....F0.....1.....2.....3.....4.....5.....6.....7.....89.....A....
                    // .B.....
                    + "\u0caa\u0cab?\u0cac\u0cad\u0cae\u0caf\u0cb0\u0cb1\u0cb2\u0cb3 "
                    + "\u0cb5\u0cb6\u0cb7"
                    // C.....D.....E.....F.....0.....1.....2.....3.....4.....5.....6.....78.....9
                    // .....
                    + "\u0cb8\u0cb9\u0cbc\u0cbd\u0cbe\u0cbf\u0cc0\u0cc1\u0cc2\u0cc3\u0cc4 "
                    + "\u0cc6\u0cc7"
                    // A.....BC.....D.....E.....F.....0.....123456789ABCDEF0123456789AB.....C....
                    // .D.....
                    + "\u0cc8 \u0cca\u0ccb\u0ccc\u0ccd\u0cd5abcdefghijklmnopqrstuvwxyz\u0cd6"
                    + "\u0ce0\u0ce1"
                    // E.....F.....
                    + "\u0ce2\u0ce3",

            /* A.3.8 Malayalam National Language Locking Shift Table
             01.....2.....3.....4.....5.....6.....7.....8.....9.....A.B.....CD.E.....F.....0....
             .1 */
            " \u0d02\u0d03\u0d05\u0d06\u0d07\u0d08\u0d09\u0d0a\u0d0b\n\u0d0c \r\u0d0e\u0d0f\u0d10 "
                    // 2.....3.....4.....5.....6.....7.....8.....9.....A.....B.....C.....D.....E.
                    // ....F.....
                    + "\u0d12\u0d13\u0d14\u0d15\u0d16\u0d17\u0d18\u0d19\u0d1a\uffff\u0d1b\u0d1c"
                    + "\u0d1d\u0d1e"
                    // 012.....3.....4.....5.....6.....7.....89A.....B.....CD.....EF....
                    // .0123456789ABC
                    + " !\u0d1f\u0d20\u0d21\u0d22\u0d23\u0d24)(\u0d25\u0d26,\u0d27"
                    + ".\u0d280123456789:; "
                    // D.....E.....F0.....1.....2.....3.....4.....5.....6.....7.....8.....9.....A
                    // .....
                    + "\u0d2a\u0d2b?\u0d2c\u0d2d\u0d2e\u0d2f\u0d30\u0d31\u0d32\u0d33\u0d34\u0d35"
                    + "\u0d36"
                    // B.....C.....D.....EF.....0.....1.....2.....3.....4.....5.....6.....78....
                    // .9.....
                    + "\u0d37\u0d38\u0d39 \u0d3d\u0d3e\u0d3f\u0d40\u0d41\u0d42\u0d43\u0d44 "
                    + "\u0d46\u0d47"
                    // A.....BC.....D.....E.....F.....0.....123456789ABCDEF0123456789AB.....C....
                    // .D.....
                    + "\u0d48 \u0d4a\u0d4b\u0d4c\u0d4d\u0d57abcdefghijklmnopqrstuvwxyz\u0d60"
                    + "\u0d61\u0d62"
                    // E.....F.....
                    + "\u0d63\u0d79",

            /* A.3.9 Oriya National Language Locking Shift Table
             0.....1.....2.....3.....4.....5.....6.....7.....8.....9.....A.B.....CD.EF.....0....
             .12 */
            "\u0b01\u0b02\u0b03\u0b05\u0b06\u0b07\u0b08\u0b09\u0b0a\u0b0b\n\u0b0c \r \u0b0f\u0b10  "
                    // 3.....4.....5.....6.....7.....8.....9.....A.....B.....C.....D.....E.....F.
                    // ....01
                    + "\u0b13\u0b14\u0b15\u0b16\u0b17\u0b18\u0b19\u0b1a\uffff\u0b1b\u0b1c\u0b1d"
                    + "\u0b1e !"
                    // 2.....3.....4.....5.....6.....7.....89A.....B.....CD.....EF....
                    // .0123456789ABCD.....
                    + "\u0b1f\u0b20\u0b21\u0b22\u0b23\u0b24)(\u0b25\u0b26,\u0b27"
                    + ".\u0b280123456789:; \u0b2a"
                    // E.....F0.....1.....2.....3.....4.....56.....7.....89.....A.....B.....C....
                    // .D.....
                    + "\u0b2b?\u0b2c\u0b2d\u0b2e\u0b2f\u0b30 \u0b32\u0b33 "
                    + "\u0b35\u0b36\u0b37\u0b38\u0b39"
                    // E.....F.....0.....1.....2.....3.....4.....5.....6.....789.....A.....BCD...
                    // ..E.....
                    + "\u0b3c\u0b3d\u0b3e\u0b3f\u0b40\u0b41\u0b42\u0b43\u0b44  \u0b47\u0b48  "
                    + "\u0b4b\u0b4c"
                    // F.....0.....123456789ABCDEF0123456789AB.....C.....D.....E.....F.....
                    + "\u0b4d\u0b56abcdefghijklmnopqrstuvwxyz\u0b57\u0b60\u0b61\u0b62\u0b63",

            /* A.3.10 Punjabi National Language Locking Shift Table
             0.....1.....2.....3.....4.....5.....6.....7.....8.....9A.BCD.EF.....0.....123.....4.
             ....*/
            "\u0a01\u0a02\u0a03\u0a05\u0a06\u0a07\u0a08\u0a09\u0a0a \n  \r \u0a0f\u0a10  "
                    + "\u0a13\u0a14"
                    // 5.....6.....7.....8.....9.....A.....B.....C.....D.....E.....F.....012....
                    // .3.....
                    + "\u0a15\u0a16\u0a17\u0a18\u0a19\u0a1a\uffff\u0a1b\u0a1c\u0a1d\u0a1e "
                    + "!\u0a1f\u0a20"
                    // 4.....5.....6.....7.....89A.....B.....CD.....EF.....0123456789ABCD.....E..
                    // ...F0.....
                    + "\u0a21\u0a22\u0a23\u0a24)(\u0a25\u0a26,\u0a27.\u0a280123456789:; "
                    + "\u0a2a\u0a2b?\u0a2c"
                    // 1.....2.....3.....4.....56.....7.....89.....A.....BC.....D.....E.....F0...
                    // ..1.....
                    + "\u0a2d\u0a2e\u0a2f\u0a30 \u0a32\u0a33 \u0a35\u0a36 \u0a38\u0a39\u0a3c "
                    + "\u0a3e\u0a3f"
                    // 2.....3.....4.....56789.....A.....BCD.....E.....F.....0....
                    // .123456789ABCDEF012345678
                    + "\u0a40\u0a41\u0a42    \u0a47\u0a48  "
                    + "\u0a4b\u0a4c\u0a4d\u0a51abcdefghijklmnopqrstuvwx"
                    // 9AB.....C.....D.....E.....F.....
                    + "yz\u0a70\u0a71\u0a72\u0a73\u0a74",

            /* A.3.11 Tamil National Language Locking Shift Table
             01.....2.....3.....4.....5.....6.....7.....8.....9A.BCD.E.....F.....0.....12.....3..
             ... */
            " \u0b82\u0b83\u0b85\u0b86\u0b87\u0b88\u0b89\u0b8a \n  \r\u0b8e\u0b8f\u0b90 "
                    + "\u0b92\u0b93"
                    // 4.....5.....6789.....A.....B.....CD.....EF.....012.....3456.....7....
                    // .89ABCDEF.....
                    + "\u0b94\u0b95   \u0b99\u0b9a\uffff \u0b9c \u0b9e !\u0b9f   \u0ba3\u0ba4)(  "
                    + ", .\u0ba8"
                    // 0123456789ABC.....D.....EF012.....3.....4.....5.....6.....7.....8.....9...
                    // ..A.....
                    + "0123456789:;\u0ba9\u0baa ?  "
                    + "\u0bae\u0baf\u0bb0\u0bb1\u0bb2\u0bb3\u0bb4\u0bb5\u0bb6"
                    // B.....C.....D.....EF0.....1.....2.....3.....4.....5678.....9.....A.....BC.
                    // ....D.....
                    + "\u0bb7\u0bb8\u0bb9  \u0bbe\u0bbf\u0bc0\u0bc1\u0bc2   \u0bc6\u0bc7\u0bc8 "
                    + "\u0bca\u0bcb"
                    // E.....F.....0.....123456789ABCDEF0123456789AB.....C.....D.....E.....F.....
                    + "\u0bcc\u0bcd\u0bd0abcdefghijklmnopqrstuvwxyz\u0bd7\u0bf0\u0bf1\u0bf2\u0bf9",

            /* A.3.12 Telugu National Language Locking Shift Table
             0.....1.....2.....3.....4.....5.....6.....7.....8.....9.....A.B.....CD.E.....F.....0
             .....*/
            "\u0c01\u0c02\u0c03\u0c05\u0c06\u0c07\u0c08\u0c09\u0c0a\u0c0b\n\u0c0c "
                    + "\r\u0c0e\u0c0f\u0c10"
                    // 12.....3.....4.....5.....6.....7.....8.....9.....A.....B.....C.....D.....E
                    // .....
                    + " \u0c12\u0c13\u0c14\u0c15\u0c16\u0c17\u0c18\u0c19\u0c1a\uffff\u0c1b\u0c1c"
                    + "\u0c1d"
                    // F.....012.....3.....4.....5.....6.....7.....89A.....B.....CD.....EF....
                    // .0123456789AB
                    + "\u0c1e !\u0c1f\u0c20\u0c21\u0c22\u0c23\u0c24)(\u0c25\u0c26,\u0c27"
                    + ".\u0c280123456789:;"
                    // CD.....E.....F0.....1.....2.....3.....4.....5.....6.....7.....89.....A....
                    // .B.....
                    + " \u0c2a\u0c2b?\u0c2c\u0c2d\u0c2e\u0c2f\u0c30\u0c31\u0c32\u0c33 "
                    + "\u0c35\u0c36\u0c37"
                    // C.....D.....EF.....0.....1.....2.....3.....4.....5.....6.....78.....9....
                    // .A.....B
                    + "\u0c38\u0c39 \u0c3d\u0c3e\u0c3f\u0c40\u0c41\u0c42\u0c43\u0c44 "
                    + "\u0c46\u0c47\u0c48 "
                    // C.....D.....E.....F.....0.....123456789ABCDEF0123456789AB.....C.....D....
                    // .E.....
                    + "\u0c4a\u0c4b\u0c4c\u0c4d\u0c55abcdefghijklmnopqrstuvwxyz\u0c56\u0c60\u0c61"
                    + "\u0c62"
                    // F.....
                    + "\u0c63",

            /* A.3.13 Urdu National Language Locking Shift Table
             0.....1.....2.....3.....4.....5.....6.....7.....8.....9.....A.B.....C.....D.E.....F.
             ....*/
            "\u0627\u0622\u0628\u067b\u0680\u067e\u06a6\u062a\u06c2\u067f\n\u0679\u067d\r\u067a"
                    + "\u067c"
                    // 0.....1.....2.....3.....4.....5.....6.....7.....8.....9.....A.....B.....C.
                    // ....D.....
                    + "\u062b\u062c\u0681\u0684\u0683\u0685\u0686\u0687\u062d\u062e\u062f\uffff"
                    + "\u068c\u0688"
                    // E.....F.....012.....3.....4.....5.....6.....7.....89A.....B.....CD.....EF.
                    // ....012345
                    + "\u0689\u068a !\u068f\u068d\u0630\u0631\u0691\u0693)(\u0699\u0632,\u0696"
                    + ".\u0698012345"
                    // 6789ABC.....D.....E.....F0.....1.....2.....3.....4.....5.....6.....7.....8
                    // .....
                    + "6789:;\u069a\u0633\u0634?\u0635\u0636\u0637\u0638\u0639\u0641\u0642\u06a9"
                    + "\u06aa"
                    // 9.....A.....B.....C.....D.....E.....F.....0.....1.....2.....3.....4.....5.
                    // ....6.....
                    + "\u06ab\u06af\u06b3\u06b1\u0644\u0645\u0646\u06ba\u06bb\u06bc\u0648\u06c4"
                    + "\u06d5\u06c1"
                    // 7.....8.....9.....A.....B.....C.....D.....E.....F.....0....
                    // .123456789ABCDEF012345678
                    + "\u06be\u0621\u06cc\u06d0\u06d2\u064d\u0650\u064f\u0657"
                    + "\u0654abcdefghijklmnopqrstuvwx"
                    // 9AB.....C.....D.....E.....F.....
                    + "yz\u0655\u0651\u0653\u0656\u0670"
    };

    /**
     * GSM default extension table plus national language single shift character tables.
     */
    private static final String[] sLanguageShiftTables = new String[]{
            /* 6.2.1.1 GSM 7 bit Default Alphabet Extension Table
             0123456789A.....BCDEF0123456789ABCDEF0123456789ABCDEF
             .0123456789ABCDEF0123456789ABCDEF */
            "          \u000c         ^                   {}     \\            [~] |               "
                    // 0123456789ABCDEF012345.....6789ABCDEF0123456789ABCDEF
                    + "                     \u20ac                          ",

            /* A.2.1 Turkish National Language Single Shift Table
             0123456789A.....BCDEF0123456789ABCDEF0123456789ABCDEF.0123456789ABCDEF01234567.....8 */
            "          \u000c         ^                   {}     \\            [~] |      \u011e "
                    // 9.....ABCDEF0123.....456789ABCDEF0123.....45.....67.....89.....ABCDEF0123.
                    // ....
                    + "\u0130         \u015e               \u00e7 \u20ac \u011f \u0131         "
                    + "\u015f"
                    // 456789ABCDEF
                    + "            ",

            /* A.2.2 Spanish National Language Single Shift Table
             0123456789.....A.....BCDEF0123456789ABCDEF0123456789ABCDEF.0123456789ABCDEF01.....23 */
            "         \u00e7\u000c         ^                   {}     \\            [~] |\u00c1  "
                    // 456789.....ABCDEF.....012345.....6789ABCDEF01.....2345.....6789.....ABCDEF
                    // .....012
                    + "     \u00cd     \u00d3     \u00da           \u00e1   \u20ac   \u00ed     "
                    + "\u00f3   "
                    // 345.....6789ABCDEF
                    + "  \u00fa          ",

            /* A.2.3 Portuguese National Language Single Shift Table
             012345.....6789.....A.....B.....C.....DE.....F.....012.....3.....45.....6.....7....
             .8....*/
            "     \u00ea   \u00e7\u000c\u00d4\u00f4 \u00c1\u00e1  "
                    + "\u03a6\u0393^\u03a9\u03a0\u03a8\u03a3"
                    // 9.....ABCDEF.....0123456789ABCDEF.0123456789ABCDEF01.....23456789.....ABCDE
                    + "\u0398     \u00ca        {}     \\            [~] |\u00c0       \u00cd     "
                    // F.....012345.....6789AB.....C.....DEF01.....2345.....6789.....ABCDEF....
                    // .01234
                    + "\u00d3     \u00da     \u00c3\u00d5    \u00c2   \u20ac   \u00ed     \u00f3 "
                    + "    "
                    // 5.....6789AB.....C.....DEF.....
                    + "\u00fa     \u00e3\u00f5  \u00e2",

            /* A.2.4 Bengali National Language Single Shift Table
             01.....23.....4.....5.6.....789A.....BCDEF0123.....45.....6789.....A.....BC.....D...
             .. */
            "@\u00a3$\u00a5\u00bf\"\u00a4%&'\u000c*+ -/<=>\u00a1^\u00a1_#*\u09e6\u09e7 \u09e8\u09e9"
                    // E.....F.....0.....1.....2.....3.....4.....5.....6.....7.....89A.....B....
                    // .C.....
                    + "\u09ea\u09eb\u09ec\u09ed\u09ee\u09ef\u09df\u09e0\u09e1\u09e2{}\u09e3\u09f2"
                    + "\u09f3"
                    // D.....E.....F.0.....1.....2.....3.....4.....56789ABCDEF0123456789ABCDEF
                    + "\u09f4\u09f5\\\u09f6\u09f7\u09f8\u09f9\u09fa       [~] |ABCDEFGHIJKLMNO"
                    // 0123456789ABCDEF012345.....6789ABCDEF0123456789ABCDEF
                    + "PQRSTUVWXYZ          \u20ac                          ",

            /* A.2.5 Gujarati National Language Single Shift Table
             01.....23.....4.....5.6.....789A.....BCDEF0123.....45.....6789.....A.....BC.....D...
             .. */
            "@\u00a3$\u00a5\u00bf\"\u00a4%&'\u000c*+ -/<=>\u00a1^\u00a1_#*\u0964\u0965 \u0ae6\u0ae7"
                    // E.....F.....0.....1.....2.....3.....4.....5.....6789ABCDEF.0123456789ABCDEF
                    + "\u0ae8\u0ae9\u0aea\u0aeb\u0aec\u0aed\u0aee\u0aef  {}     \\            [~] "
                    // 0123456789ABCDEF0123456789ABCDEF012345.....6789ABCDEF0123456789ABCDEF
                    + "|ABCDEFGHIJKLMNOPQRSTUVWXYZ          \u20ac                          ",

            /* A.2.6 Hindi National Language Single Shift Table
             01.....23.....4.....5.6.....789A.....BCDEF0123.....45.....6789.....A.....BC.....D...
             .. */
            "@\u00a3$\u00a5\u00bf\"\u00a4%&'\u000c*+ -/<=>\u00a1^\u00a1_#*\u0964\u0965 \u0966\u0967"
                    // E.....F.....0.....1.....2.....3.....4.....5.....6.....7.....89A.....B....
                    // .C.....
                    + "\u0968\u0969\u096a\u096b\u096c\u096d\u096e\u096f\u0951\u0952{}\u0953\u0954"
                    + "\u0958"
                    // D.....E.....F.0.....1.....2.....3.....4.....5.....6.....7.....8.....9....
                    // .A.....
                    + "\u0959\u095a\\\u095b\u095c\u095d\u095e\u095f\u0960\u0961\u0962\u0963\u0970"
                    + "\u0971"
                    // BCDEF0123456789ABCDEF0123456789ABCDEF012345.....6789ABCDEF0123456789ABCDEF
                    + " [~] |ABCDEFGHIJKLMNOPQRSTUVWXYZ          \u20ac                          ",

            /* A.2.7 Kannada National Language Single Shift Table
             01.....23.....4.....5.6.....789A.....BCDEF0123.....45.....6789.....A.....BC.....D...
             .. */
            "@\u00a3$\u00a5\u00bf\"\u00a4%&'\u000c*+ -/<=>\u00a1^\u00a1_#*\u0964\u0965 \u0ce6\u0ce7"
                    // E.....F.....0.....1.....2.....3.....4.....5.....6.....7.....89A.....BCDEF
                    // .01234567
                    + "\u0ce8\u0ce9\u0cea\u0ceb\u0cec\u0ced\u0cee\u0cef\u0cde\u0cf1{}\u0cf2    \\"
                    + "        "
                    // 89ABCDEF0123456789ABCDEF0123456789ABCDEF012345.....6789ABCDEF0123456789ABCDEF
                    + "    [~] |ABCDEFGHIJKLMNOPQRSTUVWXYZ          \u20ac                       "
                    + "   ",

            /* A.2.8 Malayalam National Language Single Shift Table
             01.....23.....4.....5.6.....789A.....BCDEF0123.....45.....6789.....A.....BC.....D...
             .. */
            "@\u00a3$\u00a5\u00bf\"\u00a4%&'\u000c*+ -/<=>\u00a1^\u00a1_#*\u0964\u0965 \u0d66\u0d67"
                    // E.....F.....0.....1.....2.....3.....4.....5.....6.....7.....89A.....B....
                    // .C.....
                    + "\u0d68\u0d69\u0d6a\u0d6b\u0d6c\u0d6d\u0d6e\u0d6f\u0d70\u0d71{}\u0d72\u0d73"
                    + "\u0d74"
                    // D.....E.....F.0.....1.....2.....3.....4....
                    // .56789ABCDEF0123456789ABCDEF0123456789A
                    + "\u0d75\u0d7a\\\u0d7b\u0d7c\u0d7d\u0d7e\u0d7f       [~] "
                    + "|ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                    // BCDEF012345.....6789ABCDEF0123456789ABCDEF
                    + "          \u20ac                          ",

            /* A.2.9 Oriya National Language Single Shift Table
             01.....23.....4.....5.6.....789A.....BCDEF0123.....45.....6789.....A.....BC.....D...
             .. */
            "@\u00a3$\u00a5\u00bf\"\u00a4%&'\u000c*+ -/<=>\u00a1^\u00a1_#*\u0964\u0965 \u0b66\u0b67"
                    // E.....F.....0.....1.....2.....3.....4.....5.....6.....7.....89A.....B....
                    // .C.....DE
                    + "\u0b68\u0b69\u0b6a\u0b6b\u0b6c\u0b6d\u0b6e\u0b6f\u0b5c\u0b5d{}\u0b5f\u0b70"
                    + "\u0b71  "
                    // F.0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF012345....
                    // .6789ABCDEF0123456789A
                    + "\\            [~] |ABCDEFGHIJKLMNOPQRSTUVWXYZ          \u20ac             "
                    + "        "
                    // BCDEF
                    + "     ",

            /* A.2.10 Punjabi National Language Single Shift Table
             01.....23.....4.....5.6.....789A.....BCDEF0123.....45.....6789.....A.....BC.....D...
             .. */
            "@\u00a3$\u00a5\u00bf\"\u00a4%&'\u000c*+ -/<=>\u00a1^\u00a1_#*\u0964\u0965 \u0a66\u0a67"
                    // E.....F.....0.....1.....2.....3.....4.....5.....6.....7.....89A.....B....
                    // .C.....
                    + "\u0a68\u0a69\u0a6a\u0a6b\u0a6c\u0a6d\u0a6e\u0a6f\u0a59\u0a5a{}\u0a5b\u0a5c"
                    + "\u0a5e"
                    // D.....EF.0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF012345....
                    // .6789ABCDEF01
                    + "\u0a75 \\            [~] |ABCDEFGHIJKLMNOPQRSTUVWXYZ          \u20ac      "
                    + "      "
                    // 23456789ABCDEF
                    + "              ",

            /* A.2.11 Tamil National Language Single Shift Table
               NOTE: TS 23.038 V9.1.1 shows code 0x24 as \u0bef, corrected to \u0bee (typo)
             01.....23.....4.....5.6.....789A.....BCDEF0123.....45.....6789.....A.....BC.....D...
             .. */
            "@\u00a3$\u00a5\u00bf\"\u00a4%&'\u000c*+ -/<=>\u00a1^\u00a1_#*\u0964\u0965 \u0be6\u0be7"
                    // E.....F.....0.....1.....2.....3.....4.....5.....6.....7.....89A.....B....
                    // .C.....
                    + "\u0be8\u0be9\u0bea\u0beb\u0bec\u0bed\u0bee\u0bef\u0bf3\u0bf4{}\u0bf5\u0bf6"
                    + "\u0bf7"
                    // D.....E.....F.0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF012345....
                    // .6789ABC
                    + "\u0bf8\u0bfa\\            [~] |ABCDEFGHIJKLMNOPQRSTUVWXYZ          \u20ac "
                    + "      "
                    // DEF0123456789ABCDEF
                    + "                   ",

            /* A.2.12 Telugu National Language Single Shift Table
               NOTE: TS 23.038 V9.1.1 shows code 0x22-0x23 as \u06cc\u06cd, corrected to
               \u0c6c\u0c6d
             01.....23.....4.....5.6.....789A.....BCDEF0123.....45.....6789ABC.....D.....E.....F.
             .... */
            "@\u00a3$\u00a5\u00bf\"\u00a4%&'\u000c*+ -/<=>\u00a1^\u00a1_#*   "
                    + "\u0c66\u0c67\u0c68\u0c69"
                    // 0.....1.....2.....3.....4.....5.....6.....7.....89A.....B.....C.....D....
                    // .E.....F.
                    + "\u0c6a\u0c6b\u0c6c\u0c6d\u0c6e\u0c6f\u0c58\u0c59{}\u0c78\u0c79\u0c7a\u0c7b"
                    + "\u0c7c\\"
                    // 0.....1.....2.....3456789ABCDEF0123456789ABCDEF0123456789ABCDEF012345....
                    // .6789ABCD
                    + "\u0c7d\u0c7e\u0c7f         [~] |ABCDEFGHIJKLMNOPQRSTUVWXYZ          \u20ac"
                    + "        "
                    // EF0123456789ABCDEF
                    + "                  ",

            /* A.2.13 Urdu National Language Single Shift Table
             01.....23.....4.....5.6.....789A.....BCDEF0123.....45.....6789.....A.....BC.....D...
             .. */
            "@\u00a3$\u00a5\u00bf\"\u00a4%&'\u000c*+ -/<=>\u00a1^\u00a1_#*\u0600\u0601 \u06f0\u06f1"
                    // E.....F.....0.....1.....2.....3.....4.....5.....6.....7.....89A.....B....
                    // .C.....
                    + "\u06f2\u06f3\u06f4\u06f5\u06f6\u06f7\u06f8\u06f9\u060c\u060d{}\u060e\u060f"
                    + "\u0610"
                    // D.....E.....F.0.....1.....2.....3.....4.....5.....6.....7.....8.....9....
                    // .A.....
                    + "\u0611\u0612\\\u0613\u0614\u061b\u061f\u0640\u0652\u0658\u066b\u066c\u0672"
                    + "\u0673"
                    // B.....CDEF.....0123456789ABCDEF0123456789ABCDEF012345....
                    // .6789ABCDEF0123456789ABCDEF
                    + "\u06cd[~]\u06d4|ABCDEFGHIJKLMNOPQRSTUVWXYZ          \u20ac                "
                    + "          "
    };

    static {
        int numTables = sLanguageTables.length;
        int numShiftTables = sLanguageShiftTables.length;
        if (numTables != numShiftTables) {
            Log.e(TAG, "Error: language tables array length " + numTables
                    + " != shift tables array length " + numShiftTables);
        }

        sCharsToGsmTables = new SparseIntArray[numTables];
        for (int i = 0; i < numTables; i++) {
            String table = sLanguageTables[i];

            int tableLen = table.length();
            if (tableLen != 0 && tableLen != 128) {
                Log.e(TAG, "Error: language tables index " + i + " length " + tableLen
                        + " (expected 128 or 0)");
            }

            SparseIntArray charToGsmTable = new SparseIntArray(tableLen);
            sCharsToGsmTables[i] = charToGsmTable;
            for (int j = 0; j < tableLen; j++) {
                char c = table.charAt(j);
                charToGsmTable.put(c, j);
            }
        }

        sCharsToShiftTables = new SparseIntArray[numShiftTables];
        for (int i = 0; i < numShiftTables; i++) {
            String shiftTable = sLanguageShiftTables[i];

            int shiftTableLen = shiftTable.length();
            if (shiftTableLen != 0 && shiftTableLen != 128) {
                Log.e(TAG, "Error: language shift tables index " + i + " length " + shiftTableLen
                        + " (expected 128 or 0)");
            }

            SparseIntArray charToShiftTable = new SparseIntArray(shiftTableLen);
            sCharsToShiftTables[i] = charToShiftTable;
            for (int j = 0; j < shiftTableLen; j++) {
                char c = shiftTable.charAt(j);
                if (c != ' ') {
                    charToShiftTable.put(c, j);
                }
            }
        }
    }

    /**
     * Convert a GSM alphabet 7 bit packed string (SMS string) into a
     * {@link java.lang.String}.
     *
     * See TS 23.038 6.1.2.1 for SMS Character Packing
     *
     * @param pdu           the raw data from the pdu
     * @param offset        the byte offset of
     * @param lengthSeptets string length in septets, not bytes
     * @return String representation or null on decoding exception
     */
    public static String gsm7BitPackedToString(byte[] pdu, int offset,
            int lengthSeptets) {
        return gsm7BitPackedToString(pdu, offset, lengthSeptets, 0, 0, 0);
    }

    /**
     * Convert a GSM alphabet 7 bit packed string (SMS string) into a
     * {@link java.lang.String}.
     *
     * See TS 23.038 6.1.2.1 for SMS Character Packing
     *
     * @param pdu            the raw data from the pdu
     * @param offset         the byte offset of
     * @param lengthSeptets  string length in septets, not bytes
     * @param numPaddingBits the number of padding bits before the start of the
     *                       string in the first byte
     * @param languageTable  the 7 bit language table, or 0 for the default GSM alphabet
     * @param shiftTable     the 7 bit single shift language table, or 0 for the default
     *                       GSM extension table
     * @return String representation or null on decoding exception
     */
    public static String gsm7BitPackedToString(byte[] pdu, int offset,
            int lengthSeptets, int numPaddingBits, int languageTable, int shiftTable) {
        StringBuilder ret = new StringBuilder(lengthSeptets);

        if (languageTable < 0 || languageTable > sLanguageTables.length) {
            Log.w(TAG, "unknown language table " + languageTable + ", using default");
            languageTable = 0;
        }
        if (shiftTable < 0 || shiftTable > sLanguageShiftTables.length) {
            Log.w(TAG, "unknown single shift table " + shiftTable + ", using default");
            shiftTable = 0;
        }

        try {
            boolean prevCharWasEscape = false;
            String languageTableToChar = sLanguageTables[languageTable];
            String shiftTableToChar = sLanguageShiftTables[shiftTable];

            if (languageTableToChar.isEmpty()) {
                Log.w(TAG, "no language table for code " + languageTable + ", using default");
                languageTableToChar = sLanguageTables[0];
            }
            if (shiftTableToChar.isEmpty()) {
                Log.w(TAG, "no single shift table for code " + shiftTable + ", using default");
                shiftTableToChar = sLanguageShiftTables[0];
            }

            for (int i = 0; i < lengthSeptets; i++) {
                int bitOffset = (7 * i) + numPaddingBits;

                int byteOffset = bitOffset / 8;
                int shift = bitOffset % 8;
                int gsmVal;

                gsmVal = (0x7f & (pdu[offset + byteOffset] >> shift));

                // if it crosses a byte boundary
                if (shift > 1) {
                    // set msb bits to 0
                    gsmVal &= 0x7f >> (shift - 1);

                    gsmVal |= 0x7f & (pdu[offset + byteOffset + 1] << (8 - shift));
                }

                if (prevCharWasEscape) {
                    if (gsmVal == GSM_EXTENDED_ESCAPE) {
                        ret.append(' ');    // display ' ' for reserved double escape sequence
                    } else {
                        char c = shiftTableToChar.charAt(gsmVal);
                        if (c == ' ') {
                            ret.append(languageTableToChar.charAt(gsmVal));
                        } else {
                            ret.append(c);
                        }
                    }
                    prevCharWasEscape = false;
                } else if (gsmVal == GSM_EXTENDED_ESCAPE) {
                    prevCharWasEscape = true;
                } else {
                    ret.append(languageTableToChar.charAt(gsmVal));
                }
            }
        } catch (RuntimeException ex) {
            Log.e(TAG, "Error GSM 7 bit packed: ", ex);
            return null;
        }

        return ret.toString();
    }
}