com.itextpdf.barcodes.dmcode.ReedSolomon Maven / Gradle / Ivy

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/*
    This file is part of the iText (R) project.
    Copyright (c) 1998-2023 Apryse Group NV
    Authors: Apryse Software.

    This program is offered under a commercial and under the AGPL license.
    For commercial licensing, contact us at https://itextpdf.com/sales.  For AGPL licensing, see below.

    AGPL licensing:
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program 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 Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see .
 */
package com.itextpdf.barcodes.dmcode;

public final class ReedSolomon {

    private static final int[] log = {
            0, 255, 1, 240, 2, 225, 241, 53, 3, 38, 226, 133, 242, 43, 54, 210,
            4, 195, 39, 114, 227, 106, 134, 28, 243, 140, 44, 23, 55, 118, 211, 234,
            5, 219, 196, 96, 40, 222, 115, 103, 228, 78, 107, 125, 135, 8, 29, 162,
            244, 186, 141, 180, 45, 99, 24, 49, 56, 13, 119, 153, 212, 199, 235, 91,
            6, 76, 220, 217, 197, 11, 97, 184, 41, 36, 223, 253, 116, 138, 104, 193,
            229, 86, 79, 171, 108, 165, 126, 145, 136, 34, 9, 74, 30, 32, 163, 84,
            245, 173, 187, 204, 142, 81, 181, 190, 46, 88, 100, 159, 25, 231, 50, 207,
            57, 147, 14, 67, 120, 128, 154, 248, 213, 167, 200, 63, 236, 110, 92, 176,
            7, 161, 77, 124, 221, 102, 218, 95, 198, 90, 12, 152, 98, 48, 185, 179,
            42, 209, 37, 132, 224, 52, 254, 239, 117, 233, 139, 22, 105, 27, 194, 113,
            230, 206, 87, 158, 80, 189, 172, 203, 109, 175, 166, 62, 127, 247, 146, 66,
            137, 192, 35, 252, 10, 183, 75, 216, 31, 83, 33, 73, 164, 144, 85, 170,
            246, 65, 174, 61, 188, 202, 205, 157, 143, 169, 82, 72, 182, 215, 191, 251,
            47, 178, 89, 151, 101, 94, 160, 123, 26, 112, 232, 21, 51, 238, 208, 131,
            58, 69, 148, 18, 15, 16, 68, 17, 121, 149, 129, 19, 155, 59, 249, 70,
            214, 250, 168, 71, 201, 156, 64, 60, 237, 130, 111, 20, 93, 122, 177, 150
    };

    private static final int[] alog = {
            1, 2, 4, 8, 16, 32, 64, 128, 45, 90, 180, 69, 138, 57, 114, 228,
            229, 231, 227, 235, 251, 219, 155, 27, 54, 108, 216, 157, 23, 46, 92, 184,
            93, 186, 89, 178, 73, 146, 9, 18, 36, 72, 144, 13, 26, 52, 104, 208,
            141, 55, 110, 220, 149, 7, 14, 28, 56, 112, 224, 237, 247, 195, 171, 123,
            246, 193, 175, 115, 230, 225, 239, 243, 203, 187, 91, 182, 65, 130, 41, 82,
            164, 101, 202, 185, 95, 190, 81, 162, 105, 210, 137, 63, 126, 252, 213, 135,
            35, 70, 140, 53, 106, 212, 133, 39, 78, 156, 21, 42, 84, 168, 125, 250,
            217, 159, 19, 38, 76, 152, 29, 58, 116, 232, 253, 215, 131, 43, 86, 172,
            117, 234, 249, 223, 147, 11, 22, 44, 88, 176, 77, 154, 25, 50, 100, 200,
            189, 87, 174, 113, 226, 233, 255, 211, 139, 59, 118, 236, 245, 199, 163, 107,
            214, 129, 47, 94, 188, 85, 170, 121, 242, 201, 191, 83, 166, 97, 194, 169,
            127, 254, 209, 143, 51, 102, 204, 181, 71, 142, 49, 98, 196, 165, 103, 206,
            177, 79, 158, 17, 34, 68, 136, 61, 122, 244, 197, 167, 99, 198, 161, 111,
            222, 145, 15, 30, 60, 120, 240, 205, 183, 67, 134, 33, 66, 132, 37, 74,
            148, 5, 10, 20, 40, 80, 160, 109, 218, 153, 31, 62, 124, 248, 221, 151,
            3, 6, 12, 24, 48, 96, 192, 173, 119, 238, 241, 207, 179, 75, 150, 1
    };

    private static final int[] poly5 = {
            228, 48, 15, 111, 62
    };

    private static final int[] poly7 = {
            23, 68, 144, 134, 240, 92, 254
    };

    private static final int[] poly10 = {
            28, 24, 185, 166, 223, 248, 116, 255, 110, 61
    };

    private static final int[] poly11 = {
            175, 138, 205, 12, 194, 168, 39, 245, 60, 97, 120
    };

    private static final int[] poly12 = {
            41, 153, 158, 91, 61, 42, 142, 213, 97, 178, 100, 242
    };

    private static final int[] poly14 = {
            156, 97, 192, 252, 95, 9, 157, 119, 138, 45, 18, 186, 83, 185
    };

    private static final int[] poly18 = {
            83, 195, 100, 39, 188, 75, 66, 61, 241, 213, 109, 129, 94, 254, 225, 48,
            90, 188
    };

    private static final int[] poly20 = {
            15, 195, 244, 9, 233, 71, 168, 2, 188, 160, 153, 145, 253, 79, 108, 82,
            27, 174, 186, 172
    };

    private static final int[] poly24 = {
            52, 190, 88, 205, 109, 39, 176, 21, 155, 197, 251, 223, 155, 21, 5, 172,
            254, 124, 12, 181, 184, 96, 50, 193
    };

    private static final int[] poly28 = {
            211, 231, 43, 97, 71, 96, 103, 174, 37, 151, 170, 53, 75, 34, 249, 121,
            17, 138, 110, 213, 141, 136, 120, 151, 233, 168, 93, 255
    };

    private static final int[] poly36 = {
            245, 127, 242, 218, 130, 250, 162, 181, 102, 120, 84, 179, 220, 251, 80, 182,
            229, 18, 2, 4, 68, 33, 101, 137, 95, 119, 115, 44, 175, 184, 59, 25,
            225, 98, 81, 112
    };

    private static final int[] poly42 = {
            77, 193, 137, 31, 19, 38, 22, 153, 247, 105, 122, 2, 245, 133, 242, 8,
            175, 95, 100, 9, 167, 105, 214, 111, 57, 121, 21, 1, 253, 57, 54, 101,
            248, 202, 69, 50, 150, 177, 226, 5, 9, 5
    };

    private static final int[] poly48 = {
            245, 132, 172, 223, 96, 32, 117, 22, 238, 133, 238, 231, 205, 188, 237, 87,
            191, 106, 16, 147, 118, 23, 37, 90, 170, 205, 131, 88, 120, 100, 66, 138,
            186, 240, 82, 44, 176, 87, 187, 147, 160, 175, 69, 213, 92, 253, 225, 19
    };

    private static final int[] poly56 = {
            175, 9, 223, 238, 12, 17, 220, 208, 100, 29, 175, 170, 230, 192, 215, 235,
            150, 159, 36, 223, 38, 200, 132, 54, 228, 146, 218, 234, 117, 203, 29, 232,
            144, 238, 22, 150, 201, 117, 62, 207, 164, 13, 137, 245, 127, 67, 247, 28,
            155, 43, 203, 107, 233, 53, 143, 46
    };

    private static final int[] poly62 = {
            242, 93, 169, 50, 144, 210, 39, 118, 202, 188, 201, 189, 143, 108, 196, 37,
            185, 112, 134, 230, 245, 63, 197, 190, 250, 106, 185, 221, 175, 64, 114, 71,
            161, 44, 147, 6, 27, 218, 51, 63, 87, 10, 40, 130, 188, 17, 163, 31,
            176, 170, 4, 107, 232, 7, 94, 166, 224, 124, 86, 47, 11, 204
    };

    private static final int[] poly68 = {
            220, 228, 173, 89, 251, 149, 159, 56, 89, 33, 147, 244, 154, 36, 73, 127,
            213, 136, 248, 180, 234, 197, 158, 177, 68, 122, 93, 213, 15, 160, 227, 236,
            66, 139, 153, 185, 202, 167, 179, 25, 220, 232, 96, 210, 231, 136, 223, 239,
            181, 241, 59, 52, 172, 25, 49, 232, 211, 189, 64, 54, 108, 153, 132, 63,
            96, 103, 82, 186
    };

    private static int[] getPoly(int nc) {
        switch (nc) {
            case 5:
                return poly5;
            case 7:
                return poly7;
            case 10:
                return poly10;
            case 11:
                return poly11;
            case 12:
                return poly12;
            case 14:
                return poly14;
            case 18:
                return poly18;
            case 20:
                return poly20;
            case 24:
                return poly24;
            case 28:
                return poly28;
            case 36:
                return poly36;
            case 42:
                return poly42;
            case 48:
                return poly48;
            case 56:
                return poly56;
            case 62:
                return poly62;
            case 68:
                return poly68;
        }
        return null;
    }

    private static void reedSolomonBlock(byte[] wd, int nd, byte[] ncout, int nc, int[] c) {
        int i, j, k;

        for (i = 0; i <= nc; i++) ncout[i] = 0;
        for (i = 0; i < nd; i++) {
            k = (ncout[0] ^ wd[i]) & 0xff;
            for (j = 0; j < nc; j++) {
                ncout[j] = (byte) (ncout[j + 1] ^ (k == 0 ? 0 : (byte) alog[(log[k] + log[c[nc - j - 1]]) % 255]));
            }
        }
    }

    /**
     * Calculates the error correction code for the given parameters.
     * @param wd bytearray containing the data
     * @param nd size of the data
     * @param datablock size of a datablock
     * @param nc size of a errorblock
     */
    public static void generateECC(byte[] wd, int nd, int datablock, int nc) {
        int blocks = (nd + 2) / datablock;
        int b;
        byte[] buf = new byte[256];
        byte[] ecc = new byte[256];
        int[] c = getPoly(nc);
        for (b = 0; b < blocks; b++) {
            int n, p = 0;
            for (n = b; n < nd; n += blocks)
                buf[p++] = wd[n];
            reedSolomonBlock(buf, p, ecc, nc, c);
            p = 0;
            for (n = b; n < nc * blocks; n += blocks)
                wd[nd + n] = ecc[p++];
        }
    }

}