/* code.c - Handles Code 11, 39, 39+, 93, PZN, Channel and VIN */
/* LOGMARS MIL-STD-1189 Rev. B https://apps.dtic.mil/dtic/tr/fulltext/u2/a473534.pdf */
/* PZN https://www.ifaffm.de/mandanten/1/documents/04_ifa_coding_system/IFA_Info_Code_39_EN.pdf */
/* PZN https://www.ifaffm.de/mandanten/1/documents/04_ifa_coding_system/IFA-Info_Check_Digit_Calculations_PZN_PPN_UDI_EN.pdf */

/*
    libzint - the open source barcode library
    Copyright (C) 2008 - 2020 Robin Stuart <rstuart114@gmail.com>

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:

    1. Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.
    3. Neither the name of the project nor the names of its contributors
       may be used to endorse or promote products derived from this software
       without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    SUCH DAMAGE.
 */
/* vim: set ts=4 sw=4 et : */

/* In version 0.5 this file was 1,553 lines long! */

#include <stdio.h>
#include <assert.h>
#include "common.h"

#define SODIUM  "0123456789-"
#define SILVER  "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%abcd"
#define ARSENIC "0123456789ABCDEFGHJKLMNPRSTUVWXYZ"

static const char *C11Table[11] = {
    "111121", "211121", "121121", "221111", "112121", "212111", "122111",
    "111221", "211211", "211111", "112111"
};

/* Code 39 tables checked against ISO/IEC 16388:2007 */

/* Incorporates Table A1 */

static const char *C39Table[43] = {
    /* Code 39 character assignments (Table 1) */
    "1112212111", "2112111121", "1122111121", "2122111111", "1112211121",
    "2112211111", "1122211111", "1112112121", "2112112111", "1122112111", "2111121121",
    "1121121121", "2121121111", "1111221121", "2111221111", "1121221111", "1111122121",
    "2111122111", "1121122111", "1111222111", "2111111221", "1121111221", "2121111211",
    "1111211221", "2111211211", "1121211211", "1111112221", "2111112211", "1121112211",
    "1111212211", "2211111121", "1221111121", "2221111111", "1211211121", "2211211111",
    "1221211111", "1211112121", "2211112111", "1221112111", "1212121111", "1212111211",
    "1211121211", "1112121211"
};

static const char *EC39Ctrl[128] = {
    /* Encoding the full ASCII character set in Code 39 (Table A2) */
    "%U", "$A", "$B", "$C", "$D", "$E", "$F", "$G", "$H", "$I", "$J", "$K",
    "$L", "$M", "$N", "$O", "$P", "$Q", "$R", "$S", "$T", "$U", "$V", "$W", "$X", "$Y", "$Z",
    "%A", "%B", "%C", "%D", "%E", " ", "/A", "/B", "/C", "/D", "/E", "/F", "/G", "/H", "/I", "/J",
    "/K", "/L", "-", ".", "/O", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "/Z", "%F",
    "%G", "%H", "%I", "%J", "%V", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",
    "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "%K", "%L", "%M", "%N", "%O",
    "%W", "+A", "+B", "+C", "+D", "+E", "+F", "+G", "+H", "+I", "+J", "+K", "+L", "+M", "+N", "+O",
    "+P", "+Q", "+R", "+S", "+T", "+U", "+V", "+W", "+X", "+Y", "+Z", "%P", "%Q", "%R", "%S", "%T"
};

static const char *C93Ctrl[128] = {
    "bU", "aA", "aB", "aC", "aD", "aE", "aF", "aG", "aH", "aI", "aJ", "aK",
    "aL", "aM", "aN", "aO", "aP", "aQ", "aR", "aS", "aT", "aU", "aV", "aW", "aX", "aY", "aZ",
    "bA", "bB", "bC", "bD", "bE", " ", "cA", "cB", "cC", "$", "%", "cF", "cG", "cH", "cI", "cJ",
    "+", "cL", "-", ".", "/", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "cZ", "bF",
    "bG", "bH", "bI", "bJ", "bV", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",
    "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "bK", "bL", "bM", "bN", "bO",
    "bW", "dA", "dB", "dC", "dD", "dE", "dF", "dG", "dH", "dI", "dJ", "dK", "dL", "dM", "dN", "dO",
    "dP", "dQ", "dR", "dS", "dT", "dU", "dV", "dW", "dX", "dY", "dZ", "bP", "bQ", "bR", "bS", "bT"
};

static const char *C93Table[47] = {
    "131112", "111213", "111312", "111411", "121113", "121212", "121311",
    "111114", "131211", "141111", "211113", "211212", "211311", "221112", "221211", "231111",
    "112113", "112212", "112311", "122112", "132111", "111123", "111222", "111321", "121122",
    "131121", "212112", "212211", "211122", "211221", "221121", "222111", "112122", "112221",
    "122121", "123111", "121131", "311112", "311211", "321111", "112131", "113121", "211131",
    "121221", "312111", "311121", "122211"
};

/* *********************** CODE 11 ******************** */
INTERNAL int code_11(struct zint_symbol *symbol, unsigned char source[], int length) { /* Code 11 */

    int i;
    int h, c_digit, c_weight, c_count, k_digit, k_weight, k_count;
    int weight[122], error_number;
    char dest[750]; /* 6 + 121 * 6 + 2 * 6 + 5 + 1 == 750 */
    char checkstr[3];
    int num_check_digits;

    /* Suppresses clang-tidy clang-analyzer-core.UndefinedBinaryOperatorResult warning */
    assert(length > 0);

    if (length > 121) {
        strcpy(symbol->errtxt, "320: Input too long");
        return ZINT_ERROR_TOO_LONG;
    }
    error_number = is_sane(SODIUM, source, length);
    if (error_number == ZINT_ERROR_INVALID_DATA) {
        strcpy(symbol->errtxt, "321: Invalid characters in data");
        return error_number;
    }

    if (symbol->option_2 < 0 || symbol->option_2 > 2) {
        strcpy(symbol->errtxt, "339: Invalid check digit version");
        return ZINT_ERROR_INVALID_OPTION;
    }
    if (symbol->option_2 == 2) {
        num_check_digits = 0;
    } else if (symbol->option_2 == 1) {
        num_check_digits = 1;
    } else {
        num_check_digits = 2;
    }

    c_weight = 1;
    c_count = 0;
    k_weight = 1;
    k_count = 0;

    /* start character */
    strcpy(dest, "112211");

    /* Draw main body of barcode */
    for (i = 0; i < length; i++) {
        lookup(SODIUM, C11Table, source[i], dest);
        if (source[i] == '-')
            weight[i] = 10;
        else
            weight[i] = ctoi(source[i]);
    }

    if (num_check_digits) {
        /* Calculate C checksum */
        for (h = length - 1; h >= 0; h--) {
            c_count += (c_weight * weight[h]);
            c_weight++;

            if (c_weight > 10) {
                c_weight = 1;
            }
        }
        c_digit = c_count % 11;

        if (num_check_digits == 1) {
            checkstr[0] = itoc(c_digit);
            if (checkstr[0] == 'A') {
                checkstr[0] = '-';
            }
            checkstr[1] = '\0';
            lookup(SODIUM, C11Table, checkstr[0], dest);
        } else {
            weight[length] = c_digit;

            /* Calculate K checksum */
            for (h = length; h >= 0; h--) {
                k_count += (k_weight * weight[h]);
                k_weight++;

                if (k_weight > 9) {
                    k_weight = 1;
                }
            }
            k_digit = k_count % 11;

            checkstr[0] = itoc(c_digit);
            checkstr[1] = itoc(k_digit);
            if (checkstr[0] == 'A') {
                checkstr[0] = '-';
            }
            if (checkstr[1] == 'A') {
                checkstr[1] = '-';
            }
            checkstr[2] = '\0';
            lookup(SODIUM, C11Table, checkstr[0], dest);
            lookup(SODIUM, C11Table, checkstr[1], dest);
        }
    }

    /* Stop character */
    strcat(dest, "11221");

    expand(symbol, dest);

    ustrcpy(symbol->text, source);
    if (num_check_digits) {
        ustrcat(symbol->text, checkstr);
    }
    return error_number;
}

/* Code 39 */
INTERNAL int c39(struct zint_symbol *symbol, unsigned char source[], const size_t length) {
    int i;
    int counter;
    int error_number;
    char dest[880]; /* 10 (Start) + 85 * 10 + 10 (Check) + 9 (Stop) + 1 = 880 */
    char localstr[2] = {0};

    counter = 0;

    if ((symbol->option_2 < 0) || (symbol->option_2 > 1)) {
        symbol->option_2 = 0;
    }

    if ((symbol->symbology == BARCODE_LOGMARS) && (length > 30)) { /* MIL-STD-1189 Rev. B Section 5.2.6.2 */
        strcpy(symbol->errtxt, "322: Input too long");
        return ZINT_ERROR_TOO_LONG;
    } else if ((symbol->symbology == BARCODE_HIBC_39) && (length > 68)) { /* Prevent encoded_data out-of-bounds >= 143 due to wider 'wide' bars */
        strcpy(symbol->errtxt, "319: Input too long"); /* Note use 319 (2of5 range) as 340 taken by CODE128 */
        return ZINT_ERROR_TOO_LONG;
    } else if (length > 85) {
        strcpy(symbol->errtxt, "323: Input too long");
        return ZINT_ERROR_TOO_LONG;
    }
    to_upper(source);
    error_number = is_sane(SILVER, source, length);
    if (error_number == ZINT_ERROR_INVALID_DATA) {
        strcpy(symbol->errtxt, "324: Invalid characters in data");
        return error_number;
    }

    /* Start character */
    strcpy(dest, "1211212111");

    for (i = 0; i < (int) length; i++) {
        lookup(SILVER, C39Table, source[i], dest);
        counter += posn(SILVER, source[i]);
    }

    if (symbol->option_2 == 1) {

        char check_digit;
        counter = counter % 43;
        if (counter < 10) {
             check_digit = itoc(counter);
        } else {
            if (counter < 36) {
                check_digit = (counter - 10) + 'A';
            } else {
                switch (counter) {
                    case 36: check_digit = '-';
                        break;
                    case 37: check_digit = '.';
                        break;
                    case 38: check_digit = ' ';
                        break;
                    case 39: check_digit = '$';
                        break;
                    case 40: check_digit = '/';
                        break;
                    case 41: check_digit = '+';
                        break;
                    case 42: check_digit = 37;
                        break;
                    default: check_digit = ' ';
                        break; /* Keep compiler happy */
                }
            }
        }
        lookup(SILVER, C39Table, check_digit, dest);

        /* Display a space check digit as _, otherwise it looks like an error */
        if (check_digit == ' ') {
            check_digit = '_';
        }

        localstr[0] = check_digit;
        localstr[1] = '\0';
    }

    /* Stop character */
    strcat(dest, "121121211");

    if ((symbol->symbology == BARCODE_LOGMARS) || (symbol->symbology == BARCODE_HIBC_39)) {
        /* LOGMARS uses wider 'wide' bars than normal Code 39 */
        counter = strlen(dest);
        for (i = 0; i < counter; i++) {
            if (dest[i] == '2') {
                dest[i] = '3';
            }
        }
    }

    expand(symbol, dest);

    if (symbol->symbology == BARCODE_CODE39) {
        ustrcpy(symbol->text, "*");
        ustrcat(symbol->text, source);
        ustrcat(symbol->text, localstr);
        ustrcat(symbol->text, "*");
    } else {
        ustrcpy(symbol->text, source);
        ustrcat(symbol->text, localstr);
    }
    return error_number;
}

/* Pharmazentral Nummer (PZN) */
INTERNAL int pharmazentral(struct zint_symbol *symbol, unsigned char source[], int length) {

    int i, error_number, zeroes;
    unsigned int count, check_digit;
    char localstr[11];

    if (length > 7) {
        strcpy(symbol->errtxt, "325: Input wrong length");
        return ZINT_ERROR_TOO_LONG;
    }
    error_number = is_sane(NEON, source, length);
    if (error_number == ZINT_ERROR_INVALID_DATA) {
        strcpy(symbol->errtxt, "326: Invalid characters in data");
        return error_number;
    }

    localstr[0] = '-';
    zeroes = 7 - length + 1;
    for (i = 1; i < zeroes; i++)
        localstr[i] = '0';
    ustrcpy(localstr + zeroes, source);

    count = 0;
    for (i = 1; i < 8; i++) {
        count += i * ctoi(localstr[i]);
    }

    check_digit = count % 11;

    if (symbol->debug & ZINT_DEBUG_PRINT) {
        printf("PZN: %s, check digit %d\n", localstr, check_digit);
    }

    if (check_digit == 10) {
        strcpy(symbol->errtxt, "327: Invalid PZN Data");
        return ZINT_ERROR_INVALID_DATA;
    }
    localstr[8] = itoc(check_digit);
    localstr[9] = '\0';
    error_number = c39(symbol, (unsigned char *) localstr, strlen(localstr));
    ustrcpy(symbol->text, "PZN ");
    ustrcat(symbol->text, localstr);
    return error_number;
}

/* Extended Code 39 - ISO/IEC 16388:2007 Annex A */
INTERNAL int ec39(struct zint_symbol *symbol, unsigned char source[], int length) {

    unsigned char buffer[85 * 2 + 1] = {0};
    int i;
    int error_number;

    if (length > 85) {
        strcpy(symbol->errtxt, "328: Input too long");
        return ZINT_ERROR_TOO_LONG;
    }

    /* Creates a buffer string and places control characters into it */
    for (i = 0; i < length; i++) {
        if (source[i] > 127) {
            /* Cannot encode extended ASCII */
            strcpy(symbol->errtxt, "329: Invalid characters in input data");
            return ZINT_ERROR_INVALID_DATA;
        }
        ustrcat(buffer, EC39Ctrl[source[i]]);
    }

    /* Then sends the buffer to the C39 function */
    error_number = c39(symbol, buffer, ustrlen(buffer));

    for (i = 0; i < length; i++)
        symbol->text[i] = source[i] ? source[i] : ' ';
    symbol->text[length] = '\0';

    return error_number;
}

/* Code 93 is an advancement on Code 39 and the definition is a lot tighter */
INTERNAL int c93(struct zint_symbol *symbol, unsigned char source[], int length) {

    /* SILVER includes the extra characters a, b, c and d to represent Code 93 specific
       shift characters 1, 2, 3 and 4 respectively. These characters are never used by
       c39() and ec39() */

    int i;
    int h, weight, c, k, values[128], error_number;
    char buffer[220];
    char dest[670];
    char set_copy[] = SILVER;

    error_number = 0;
    strcpy(buffer, "");

    if (length > 107) {
        strcpy(symbol->errtxt, "330: Input too long");
        return ZINT_ERROR_TOO_LONG;
    }

    /* Message Content */
    for (i = 0; i < length; i++) {
        if (source[i] > 127) {
            /* Cannot encode extended ASCII */
            strcpy(symbol->errtxt, "331: Invalid characters in input data");
            return ZINT_ERROR_INVALID_DATA;
        }
        strcat(buffer, C93Ctrl[source[i]]);
        symbol->text[i] = source[i] ? source[i] : ' ';
    }

    /* Now we can check the true length of the barcode */
    h = (int) strlen(buffer);
    if (h > 107) {
        strcpy(symbol->errtxt, "332: Input too long");
        return ZINT_ERROR_TOO_LONG;
    }

    for (i = 0; i < h; i++) {
        values[i] = posn(SILVER, buffer[i]);
    }

    /* Putting the data into dest[] is not done until after check digits are calculated */

    /* Check digit C */
    c = 0;
    weight = 1;
    for (i = h - 1; i >= 0; i--) {
        c += values[i] * weight;
        weight++;
        if (weight == 21)
            weight = 1;
    }
    c = c % 47;
    values[h] = c;
    buffer[h] = set_copy[c];

    /* Check digit K */
    k = 0;
    weight = 1;
    for (i = h; i >= 0; i--) {
        k += values[i] * weight;
        weight++;
        if (weight == 16)
            weight = 1;
    }
    k = k % 47;
    buffer[++h] = set_copy[k];
    buffer[++h] = '\0';

    /* Start character */
    strcpy(dest, "111141");

    for (i = 0; i < h; i++) {
        lookup(SILVER, C93Table, buffer[i], dest);
    }

    /* Stop character */
    strcat(dest, "1111411");
    expand(symbol, dest);

    symbol->text[length] = set_copy[c];
    symbol->text[length + 1] = set_copy[k];
    symbol->text[length + 2] = '\0';

    return error_number;
}

typedef const struct s_channel_precalc {
    long value; unsigned char B[8]; unsigned char S[8]; unsigned char bmax[7]; unsigned char smax[7];
} channel_precalc;

//#define CHANNEL_GENERATE_PRECALCS

#ifdef CHANNEL_GENERATE_PRECALCS
/* To generate precalc tables uncomment define and run "./test_channel -f generate -g" and place result in "channel_precalcs.h" */
static void channel_generate_precalc(int channels, long value, int mod, int last, int B[8], int S[8], int bmax[7], int smax[7]) {
    int i;
    if (value == mod) printf("static channel_precalc channel_precalcs%d[] = {\n", channels);
    printf("    { %7ld, {", value); for (i = 0; i < 8; i++) printf(" %d,", B[i]); printf(" },");
    printf(" {"); for (i = 0; i < 8; i++) printf(" %d,", S[i]); printf(" },");
    printf(" {"); for (i = 0; i < 7; i++) printf(" %d,", bmax[i]); printf(" },");
    printf(" {"); for (i = 0; i < 7; i++) printf(" %d,", smax[i]); printf(" }, },\n");
    if (value == last) printf("};\n");
}
#else
#include "channel_precalcs.h"
#endif

static long channel_copy_precalc(channel_precalc precalc, int B[8], int S[8], int bmax[7], int smax[7]) {
    int i;

    for (i = 0; i < 7; i++) {
        B[i] = precalc.B[i];
        S[i] = precalc.S[i];
        bmax[i] = precalc.bmax[i];
        smax[i] = precalc.smax[i];
    }
    B[7] = precalc.B[7];
    S[7] = precalc.S[7];

    return precalc.value;
}

/* CHNCHR is adapted from ANSI/AIM BC12-1998 Annex D Figure D5 and is Copyright (c) AIM 1997 */

/* It is used here on the understanding that it forms part of the specification
   for Channel Code and therefore its use is permitted under the following terms
   set out in that document:

   "It is the intent and understanding of AIM [t]hat the symbology presented in this
   specification is entirely in the public domain and free of all use restrictions,
   licenses and fees. AIM USA, its member companies, or individual officers
   assume no liability for the use of this document." */

static void CHNCHR(int channels, long target_value, int B[8], int S[8]) {
    /* Use of initial pre-calculations taken from Barcode Writer in Pure PostScript (bwipp)
     * Copyright (c) 2004-2020 Terry Burton (MIT/X-Consortium license) */
    static channel_precalc initial_precalcs[6] = {
        { 0, { 1, 1, 1, 1, 1, 2, 1, 2, }, { 1, 1, 1, 1, 1, 1, 1, 3, }, { 1, 1, 1, 1, 1, 3, 2, }, { 1, 1, 1, 1, 1, 3, 3, }, },
        { 0, { 1, 1, 1, 1, 2, 1, 1, 3, }, { 1, 1, 1, 1, 1, 1, 1, 4, }, { 1, 1, 1, 1, 4, 3, 3, }, { 1, 1, 1, 1, 4, 4, 4, }, },
        { 0, { 1, 1, 1, 2, 1, 1, 2, 3, }, { 1, 1, 1, 1, 1, 1, 1, 5, }, { 1, 1, 1, 5, 4, 4, 4, }, { 1, 1, 1, 5, 5, 5, 5, }, },
        { 0, { 1, 1, 2, 1, 1, 2, 1, 4, }, { 1, 1, 1, 1, 1, 1, 1, 6, }, { 1, 1, 6, 5, 5, 5, 4, }, { 1, 1, 6, 6, 6, 6, 6, }, },
        { 0, { 1, 2, 1, 1, 2, 1, 1, 5, }, { 1, 1, 1, 1, 1, 1, 1, 7, }, { 1, 7, 6, 6, 6, 5, 5, }, { 1, 7, 7, 7, 7, 7, 7, }, },
        { 0, { 2, 1, 1, 2, 1, 1, 2, 5, }, { 1, 1, 1, 1, 1, 1, 1, 8, }, { 8, 7, 7, 7, 6, 6, 6, }, { 8, 8, 8, 8, 8, 8, 8, }, },
    };
    int bmax[7], smax[7];
    long value = 0;

    channel_copy_precalc(initial_precalcs[channels - 3], B, S, bmax, smax);

#ifndef CHANNEL_GENERATE_PRECALCS
    if (channels == 7 && target_value >= channel_precalcs7[0].value) {
        value = channel_copy_precalc(channel_precalcs7[(target_value / channel_precalcs7[0].value) - 1], B, S, bmax, smax);
    } else if (channels == 8 && target_value >= channel_precalcs8[0].value) {
        value = channel_copy_precalc(channel_precalcs8[(target_value / channel_precalcs8[0].value) - 1], B, S, bmax, smax);
    }
#endif

    goto chkchr;

ls0:smax[1] = smax[0] + 1 - S[0]; B[0] = 1;
    if (S[0] == 1) goto nb0;
lb0:    bmax[1] = bmax[0] + 1 - B[0]; S[1] = 1;
ls1:        smax[2] = smax[1] + 1 - S[1]; B[1] = 1;
            if (S[0] + B[0] + S[1] == 3) goto nb1;
lb1:            bmax[2] = bmax[1] + 1 - B[1]; S[2] = 1;
ls2:                smax[3] = smax[2] + 1 - S[2]; B[2] = 1;
                    if (B[0] + S[1] + B[1] + S[2] == 4) goto nb2;
lb2:                    bmax[3] = bmax[2] + 1 - B[2]; S[3] = 1;
ls3:                        smax[4] = smax[3] + 1 - S[3]; B[3] = 1;
                            if (B[1] + S[2] + B[2] + S[3] == 4) goto nb3;
lb3:                            bmax[4] = bmax[3] + 1 - B[3]; S[4] = 1;
ls4:                                smax[5] = smax[4] + 1 - S[4]; B[4] = 1;
                                    if (B[2] + S[3] + B[3] + S[4] == 4) goto nb4;
lb4:                                    bmax[5] = bmax[4] + 1 - B[4]; S[5] = 1;
ls5:                                        smax[6] = smax[5] + 1 - S[5]; B[5] = 1;
                                            if (B[3] + S[4] + B[4] + S[5] == 4) goto nb5;
lb5:                                            bmax[6] = bmax[5] + 1 - B[5]; S[6] = 1;
ls6:                                                S[7] = smax[6] + 1 - S[6]; B[6] = 1;
                                                    if (B[4] + S[5] + B[5] + S[6] == 4) goto nb6;
lb6:                                                    B[7] = bmax[6] + 1 - B[6];
                                                        if (B[5] + S[6] + B[6] + S[7] + B[7] == 5) goto nb6;
chkchr:
#ifdef CHANNEL_GENERATE_PRECALCS
                                                        if (channels == 7 && value && value % 115338 == 0) { /* 115338 == (576688 + 2) / 5 */
                                                            channel_generate_precalc(channels, value, 115338, 115338 * (5 - 1), B, S, bmax, smax);
                                                        } else if (channels == 8 && value && value % 119121 == 0) { /* 119121 == (7742862 + 3) / 65 */
                                                            channel_generate_precalc(channels, value, 119121, 119121 * (65 - 1), B, S, bmax, smax);
                                                        }
#endif
                                                        if (value == target_value) return;
                                                        value++;
nb6:                                                    if (++B[6] <= bmax[6]) goto lb6;
                                                    if (++S[6] <= smax[6]) goto ls6;
nb5:                                            if (++B[5] <= bmax[5]) goto lb5;
                                            if (++S[5] <= smax[5]) goto ls5;
nb4:                                    if (++B[4] <= bmax[4]) goto lb4;
                                    if (++S[4] <= smax[4]) goto ls4;
nb3:                            if (++B[3] <= bmax[3]) goto lb3;
                            if (++S[3] <= smax[3]) goto ls3;
nb2:                    if (++B[2] <= bmax[2]) goto lb2;
                    if (++S[2] <= smax[2]) goto ls2;
nb1:            if (++B[1] <= bmax[1]) goto lb1;
            if (++S[1] <= smax[1]) goto ls1;
nb0:    if (++B[0] <= bmax[0]) goto lb0;
    if (++S[0] <= smax[0]) goto ls0;
}

/* Channel Code - According to ANSI/AIM BC12-1998 */
INTERNAL int channel_code(struct zint_symbol *symbol, unsigned char source[], int length) {
    int S[8] = {0}, B[8] = {0};
    long target_value = 0;
    char pattern[30];
    int channels, i;
    int error_number, range = 0, zeroes;
    char hrt[9];

    if (length > 7) {
        strcpy(symbol->errtxt, "333: Input too long");
        return ZINT_ERROR_TOO_LONG;
    }
    error_number = is_sane(NEON, source, length);
    if (error_number == ZINT_ERROR_INVALID_DATA) {
        strcpy(symbol->errtxt, "334: Invalid characters in data");
        return error_number;
    }

    if ((symbol->option_2 < 3) || (symbol->option_2 > 8)) {
        channels = 0;
    } else {
        channels = symbol->option_2;
    }

    for (i = 0; i < length; i++) {
        target_value *= 10;
        target_value += ctoi((char) source[i]);
    }

    if (channels == 0) {
        channels = length + 1;
        if (target_value > 576688 && channels < 8) {
            channels = 8;
        } else if (target_value > 44072 && channels < 7) {
            channels = 7;
        } else if (target_value > 3493 && channels < 6) {
            channels = 6;
        } else if (target_value > 292 && channels < 5) {
            channels = 5;
        } else if (target_value > 26 && channels < 4) {
            channels = 4;
        }
    }
    if (channels == 2) {
        channels = 3;
    }

    switch (channels) {
        case 3: if (target_value > 26) {
                range = 1;
            }
            break;
        case 4: if (target_value > 292) {
                range = 1;
            }
            break;
        case 5: if (target_value > 3493) {
                range = 1;
            }
            break;
        case 6: if (target_value > 44072) {
                range = 1;
            }
            break;
        case 7: if (target_value > 576688) {
                range = 1;
            }
            break;
        case 8: if (target_value > 7742862) {
                range = 1;
            }
            break;
    }
    if (range) {
        strcpy(symbol->errtxt, "335: Value out of range");
        return ZINT_ERROR_INVALID_DATA;
    }

    CHNCHR(channels, target_value, B, S);

    strcpy(pattern, "111111111"); /* Finder pattern */
    for (i = 8 - channels; i < 8; i++) {
        char part[3];
        part[0] = itoc(S[i]);
        part[1] = itoc(B[i]);
        part[2] = '\0';
        strcat(pattern, part);
    }

    zeroes = channels - 1 - length;
    if (zeroes < 0) {
        zeroes = 0;
    }
    memset(hrt, '0', zeroes);
    ustrcpy(hrt + zeroes, source);
    ustrcpy(symbol->text, hrt);

    expand(symbol, pattern);

    return error_number;
}

/* Vehicle Identification Number (VIN) */
INTERNAL int vin(struct zint_symbol *symbol, const unsigned char source[], const size_t in_length) {

    /* This code verifies the check digit present in North American VIN codes */

    char local_source[18];
    char dest[200];
    char input_check;
    char output_check;
    int value[17];
    int weight[17] = {8, 7, 6, 5, 4, 3, 2, 10, 0, 9, 8, 7, 6, 5, 4, 3, 2};
    int sum;
    int i;
    int length = (int) in_length;

    // Check length
    if (length != 17) {
        strcpy(symbol->errtxt, "336: Input wrong length, 17 characters required");
        return ZINT_ERROR_TOO_LONG;
    }

    // Check input characters, I, O and Q are not allowed
    if (is_sane(ARSENIC, source, length) == ZINT_ERROR_INVALID_DATA) {
        strcpy(symbol->errtxt, "337: Invalid characters in input data");
        return ZINT_ERROR_INVALID_DATA;
    }

    ustrcpy(local_source, source);

    to_upper((unsigned char *) local_source);


    // Check digit only valid for North America
    if (local_source[0] >= '1' && local_source[0] <= '5') {
        input_check = local_source[8];

        for (i = 0; i < 17; i++) {
            if ((local_source[i] >= '0') && (local_source[i] <= '9')) {
                value[i] = local_source[i] - '0';
            } else if ((local_source[i] >= 'A') && (local_source[i] <= 'I')) {
                value[i] = (local_source[i] - 'A') + 1;
            } else if ((local_source[i] >= 'J') && (local_source[i] <= 'R')) {
                value[i] = (local_source[i] - 'J') + 1;
            } else if ((local_source[i] >= 'S') && (local_source[i] <= 'Z')) {
                value[i] = (local_source[i] - 'S') + 2;
            }
        }

        sum = 0;
        for (i = 0; i < 17; i++) {
            sum += value[i] * weight[i];
        }

        output_check = '0' + (sum % 11);

        if (output_check == ':') {
            // Check digit was 10
            output_check = 'X';
        }

        if (symbol->debug & ZINT_DEBUG_PRINT) {
            printf("Producing VIN code: %s\n", local_source);
            printf("Input check was %c, calculated check is %c\n", input_check, output_check);
        }

        if (input_check != output_check) {
            strcpy(symbol->errtxt, "338: Invalid check digit in input data");
            return ZINT_ERROR_INVALID_DATA;
        }
    }

    /* Start character */
    strcpy(dest, "1211212111");

    /* Import character 'I' prefix? */
    if (symbol->option_2 & 1) {
        strcat(dest, "1121122111");
    }

    // Copy glyphs to symbol
    for (i = 0; i < 17; i++) {
        lookup(SILVER, C39Table, local_source[i], dest);
    }

    strcat(dest, "121121211");

    ustrcpy(symbol->text, local_source);
    expand(symbol, dest);

    return 0;
}