zint/backend/gridmtx.c

/*  gridmtx.c - Grid Matrix

    libzint - the open source barcode library
    Copyright (C) 2009-2020 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 : */

/* This file implements Grid Matrix as specified in
   AIM Global Document Number AIMD014 Rev. 1.63 Revised 9 Dec 2008 */

#include <stdio.h>
#include <string.h>
#ifdef _MSC_VER
#include <malloc.h>
#endif
#include "common.h"
#include "reedsol.h"
#include "gridmtx.h"
#include "gb2312.h"

/* define_mode() stuff */

/* Bits multiplied by this for costs, so as to be whole integer divisible by 2 and 3 */
#define GM_MULT 6

static const char numeral_nondigits[] = " +-.,"; /* Non-digit numeral set, excluding EOL (carriage return/linefeed) */

/* Whether in numeral or not. If in numeral, *p_numeral_end is set to position after numeral, and *p_numeral_cost is set to per-numeral cost */
static int in_numeral(const unsigned int gbdata[], const size_t length, const unsigned int posn, unsigned int* p_numeral_end, unsigned int* p_numeral_cost) {
    unsigned int i, digit_cnt, nondigit, nondigit_posn;

    if (posn < *p_numeral_end) {
        return 1;
    }

    /* Attempt to calculate the average 'cost' of using numeric mode in number of bits (times GM_MULT) */
    /* Also ensures that numeric mode is not selected when it cannot be used: for example in
       a string which has "2.2.0" (cannot have more than one non-numeric character for each
       block of three numeric characters) */
    for (i = posn, digit_cnt = 0, nondigit = 0, nondigit_posn = 0; i < length && i < posn + 4 && digit_cnt < 3; i++) {
        if (gbdata[i] >= '0' && gbdata[i] <= '9') {
            digit_cnt++;
        } else if (strchr(numeral_nondigits, gbdata[i])) {
            if (nondigit) {
                break;
            }
            nondigit = 1;
            nondigit_posn = i;
        } else if (i < length - 1 && gbdata[i] == 13 && gbdata[i + 1] == 10) {
            if (nondigit) {
                break;
            }
            i++;
            nondigit = 2;
            nondigit_posn = i;
        } else {
            break;
        }
    }
    if (digit_cnt == 0) { /* Must have at least one digit */
        *p_numeral_end = 0;
        return 0;
    }
    if (nondigit && nondigit_posn == i - 1) { /* Non-digit can't be at end */
        nondigit = 0;
    }
    *p_numeral_end = posn + digit_cnt + nondigit;
    /* Calculate per-numeral cost where 120 == (10 + 10) * GM_MULT, 60 == 10 * GM_MULT */
    if (digit_cnt == 3) {
        *p_numeral_cost = nondigit == 2 ? 24 /* (120 / 5) */ : nondigit == 1 ? 30 /* (120 / 4) */ : 20 /* (60 / 3) */;
    } else if (digit_cnt == 2) {
        *p_numeral_cost = nondigit == 2 ? 30 /* (120 / 4) */ : nondigit == 1 ? 40 /* (120 / 3) */ : 30 /* (60 / 2) */;
    } else {
        *p_numeral_cost = nondigit == 2 ? 40 /* (120 / 3) */ : nondigit == 1 ? 60 /* (120 / 2) */ : 60 /* (60 / 1) */;
    }
    return 1;
}

/* Encoding modes */
#define GM_CHINESE  'H'
#define GM_NUMBER   'N'
#define GM_LOWER    'L'
#define GM_UPPER    'U'
#define GM_MIXED    'M'
#define GM_BYTE     'B'
/* Note Control is a submode of Lower, Upper and Mixed modes */

/* Indexes into mode_types array */
#define GM_H   0 /* Chinese (Hanzi) */
#define GM_N   1 /* Numeral */
#define GM_L   2 /* Lower case */
#define GM_U   3 /* Upper case */
#define GM_M   4 /* Mixed */
#define GM_B   5 /* Byte */

#define GM_NUM_MODES 6

/* Initial mode costs */
static unsigned int head_costs[GM_NUM_MODES] = {
/*  H            N (+pad prefix)    L            U            M            B (+byte count) */
    4 * GM_MULT, (4 + 2) * GM_MULT, 4 * GM_MULT, 4 * GM_MULT, 4 * GM_MULT, (4 + 9) * GM_MULT
};

static unsigned int* gm_head_costs(unsigned int state[]) {
    (void)state; /* Unused */
    return head_costs;
}

/* Cost of switching modes from k to j - see AIMD014 Rev. 1.63 Table 9 – Type conversion codes */
static unsigned int gm_switch_cost(unsigned int state[], const int k, const int j) {
    static const unsigned int switch_costs[GM_NUM_MODES][GM_NUM_MODES] = {
        /*      H             N                   L             U             M             B  */
        /*H*/ {            0, (13 + 2) * GM_MULT, 13 * GM_MULT, 13 * GM_MULT, 13 * GM_MULT, (13 + 9) * GM_MULT },
        /*N*/ { 10 * GM_MULT,                  0, 10 * GM_MULT, 10 * GM_MULT, 10 * GM_MULT, (10 + 9) * GM_MULT },
        /*L*/ {  5 * GM_MULT,  (5 + 2) * GM_MULT,            0,  5 * GM_MULT,  7 * GM_MULT,  (7 + 9) * GM_MULT },
        /*U*/ {  5 * GM_MULT,  (5 + 2) * GM_MULT,  5 * GM_MULT,            0,  7 * GM_MULT,  (7 + 9) * GM_MULT },
        /*M*/ { 10 * GM_MULT, (10 + 2) * GM_MULT, 10 * GM_MULT, 10 * GM_MULT,            0, (10 + 9) * GM_MULT },
        /*B*/ {  4 * GM_MULT,  (4 + 2) * GM_MULT,  4 * GM_MULT,  4 * GM_MULT,  4 * GM_MULT,                  0 },
    };

    (void)state; /* Unused */
    return switch_costs[k][j];
}

/* Final end-of-data cost - see AIMD014 Rev. 1.63 Table 9 – Type conversion codes */
static unsigned int gm_eod_cost(unsigned int state[], const int k) {
    static const unsigned int eod_costs[GM_NUM_MODES] = {
    /*  H             N             L            U            M             B  */
        13 * GM_MULT, 10 * GM_MULT, 5 * GM_MULT, 5 * GM_MULT, 10 * GM_MULT, 4 * GM_MULT
    };

    (void)state; /* Unused */
    return eod_costs[k];
}

/* Calculate cost of encoding current character */
static void gm_cur_cost(unsigned int state[], const unsigned int gbdata[], const size_t length, const int i, char* char_modes, unsigned int prev_costs[], unsigned int cur_costs[]) {
    int cm_i = i * GM_NUM_MODES;
    int double_byte, space, numeric, lower, upper, control, double_digit, eol;
    unsigned int* p_numeral_end = &state[0];
    unsigned int* p_numeral_cost = &state[1];
    unsigned int* p_byte_count = &state[2];

    double_byte = gbdata[i] > 0xFF;
    space = gbdata[i] == ' ';
    numeric = gbdata[i] >= '0' && gbdata[i] <= '9';
    lower = gbdata[i] >= 'a' && gbdata[i] <= 'z';
    upper = gbdata[i] >= 'A' && gbdata[i] <= 'Z';
    control = !space && !numeric && !lower && !upper && gbdata[i] < 0x7F; /* Exclude DEL */
    double_digit = i < (int) length - 1 && numeric && gbdata[i + 1] >= '0' && gbdata[i + 1] <= '9';
    eol = i < (int) length - 1 && gbdata[i] == 13 && gbdata[i + 1] == 10;

    /* Hanzi mode can encode anything */
    cur_costs[GM_H] = prev_costs[GM_H] + (double_digit || eol ? 39 : 78); /* (6.5 : 13) * GM_MULT */
    char_modes[cm_i + GM_H] = GM_CHINESE;

    /* Byte mode can encode anything */
    if (*p_byte_count == 512 || (double_byte && *p_byte_count == 511)) {
        cur_costs[GM_B] = head_costs[GM_B];
        if (double_byte && *p_byte_count == 511) {
            cur_costs[GM_B] += 48; /* 8 * GM_MULT */
            double_byte = 0; /* Splitting double-byte so mark as single */
        }
        *p_byte_count = 0;
    }
    cur_costs[GM_B] += prev_costs[GM_B] + (double_byte ? 96 : 48); /* (16 : 8) * GM_MULT */
    char_modes[cm_i + GM_B] = GM_BYTE;
    *p_byte_count += double_byte ? 2 : 1;

    if (in_numeral(gbdata, length, i, p_numeral_end, p_numeral_cost)) {
        cur_costs[GM_N] = prev_costs[GM_N] + *p_numeral_cost;
        char_modes[cm_i + GM_N] = GM_NUMBER;
    }

    if (control) {
        cur_costs[GM_L] = prev_costs[GM_L] + 78; /* (7 + 6) * GM_MULT */
        char_modes[cm_i + GM_L] = GM_LOWER;
        cur_costs[GM_U] = prev_costs[GM_U] + 78; /* (7 + 6) * GM_MULT */
        char_modes[cm_i + GM_U] = GM_UPPER;
        cur_costs[GM_M] = prev_costs[GM_M] + 96; /* (10 + 6) * GM_MULT */
        char_modes[cm_i + GM_M] = GM_MIXED;
    } else {
        if (lower || space) {
            cur_costs[GM_L] = prev_costs[GM_L] + 30; /* 5 * GM_MULT */
            char_modes[cm_i + GM_L] = GM_LOWER;
        }
        if (upper || space) {
            cur_costs[GM_U] = prev_costs[GM_U] + 30; /* 5 * GM_MULT */
            char_modes[cm_i + GM_U] = GM_UPPER;
        }
        if (numeric || lower || upper || space) {
            cur_costs[GM_M] = prev_costs[GM_M] + 36; /* 6 * GM_MULT */
            char_modes[cm_i + GM_M] = GM_MIXED;
        }
    }
}

/* Calculate optimized encoding modes */
static void define_mode(char* mode, const unsigned int gbdata[], const size_t length, const int debug) {
    static const char mode_types[] = { GM_CHINESE, GM_NUMBER, GM_LOWER, GM_UPPER, GM_MIXED, GM_BYTE }; /* Must be in same order as GM_H etc */
    unsigned int state[3] = { 0 /*numeral_end*/, 0 /*numeral_cost*/, 0 /*byte_count*/ };

    pn_define_mode(mode, gbdata, length, debug, state, mode_types, GM_NUM_MODES, gm_head_costs, gm_switch_cost, gm_eod_cost, gm_cur_cost);
}

/* Add the length indicator for byte encoded blocks */
static void add_byte_count(char binary[], const size_t byte_count_posn, const int byte_count) {
    /* AIMD014 6.3.7: "Let L be the number of bytes of input data to be encoded in the 8-bit binary data set.
     * First output (L-1) as a 9-bit binary prefix to record the number of bytes..." */
    bin_append_posn(byte_count - 1, 9, binary, byte_count_posn);
}

/* Add a control character to the data stream */
static void add_shift_char(char binary[], int shifty, int debug) {
    int i;
    int glyph = 0;

    for (i = 0; i < 64; i++) {
        if (shift_set[i] == shifty) {
            glyph = i;
            break;
        }
    }

    if (debug & ZINT_DEBUG_PRINT) {
        printf("SHIFT [%d] ", glyph);
    }

    bin_append(glyph, 6, binary);
}

static int gm_encode(unsigned int gbdata[], const size_t length, char binary[], const int reader, const int eci, int debug) {
    /* Create a binary stream representation of the input data.
       7 sets are defined - Chinese characters, Numerals, Lower case letters, Upper case letters,
       Mixed numerals and latters, Control characters and 8-bit binary data */
    unsigned int sp;
    int current_mode, last_mode;
    unsigned int glyph = 0;
    int c1, c2, done;
    int p = 0, ppos;
    int numbuf[3], punt = 0;
    size_t number_pad_posn, byte_count_posn = 0;
    int byte_count = 0;
    int shift;
#ifndef _MSC_VER
    char mode[length];
#else
    char* mode = (char*) _alloca(length);
#endif

    strcpy(binary, "");

    sp = 0;
    current_mode = 0;
    last_mode = 0;
    number_pad_posn = 0;

    if (reader) {
        bin_append(10, 4, binary); /* FNC3 - Reader Initialisation */
    }

    if (eci != 0) {
        /* ECI assignment according to Table 8 */
        bin_append(12, 4, binary); /* ECI */
        if (eci <= 1023) {
            bin_append(eci, 11, binary);
        }
        if ((eci >= 1024) && (eci <= 32767)) {
            strcat(binary, "10");
            bin_append(eci, 15, binary);
        }
        if (eci >= 32768) {
            strcat(binary, "11");
            bin_append(eci, 20, binary);
        }
    }

    define_mode(mode, gbdata, length, debug);

    do {
        int next_mode = mode[sp];

        if (next_mode != current_mode) {
            switch (current_mode) {
                case 0:
                    switch (next_mode) {
                        case GM_CHINESE: bin_append(1, 4, binary);
                            break;
                        case GM_NUMBER: bin_append(2, 4, binary);
                            break;
                        case GM_LOWER: bin_append(3, 4, binary);
                            break;
                        case GM_UPPER: bin_append(4, 4, binary);
                            break;
                        case GM_MIXED: bin_append(5, 4, binary);
                            break;
                        case GM_BYTE: bin_append(6, 4, binary);
                            break;
                    }
                    break;
                case GM_CHINESE:
                    switch (next_mode) {
                        case GM_NUMBER: bin_append(8161, 13, binary);
                            break;
                        case GM_LOWER: bin_append(8162, 13, binary);
                            break;
                        case GM_UPPER: bin_append(8163, 13, binary);
                            break;
                        case GM_MIXED: bin_append(8164, 13, binary);
                            break;
                        case GM_BYTE: bin_append(8165, 13, binary);
                            break;
                    }
                    break;
                case GM_NUMBER:
                    /* add numeric block padding value */
                    switch (p) {
                        case 1: binary[number_pad_posn] = '1';
                            binary[number_pad_posn + 1] = '0';
                            break; // 2 pad digits
                        case 2: binary[number_pad_posn] = '0';
                            binary[number_pad_posn + 1] = '1';
                            break; // 1 pad digits
                        case 3: binary[number_pad_posn] = '0';
                            binary[number_pad_posn + 1] = '0';
                            break; // 0 pad digits
                    }
                    switch (next_mode) {
                        case GM_CHINESE: bin_append(1019, 10, binary);
                            break;
                        case GM_LOWER: bin_append(1020, 10, binary);
                            break;
                        case GM_UPPER: bin_append(1021, 10, binary);
                            break;
                        case GM_MIXED: bin_append(1022, 10, binary);
                            break;
                        case GM_BYTE: bin_append(1023, 10, binary);
                            break;
                    }
                    break;
                case GM_LOWER:
                case GM_UPPER:
                    switch (next_mode) {
                        case GM_CHINESE: bin_append(28, 5, binary);
                            break;
                        case GM_NUMBER: bin_append(29, 5, binary);
                            break;
                        case GM_LOWER:
                        case GM_UPPER: bin_append(30, 5, binary);
                            break;
                        case GM_MIXED: bin_append(124, 7, binary);
                            break;
                        case GM_BYTE: bin_append(126, 7, binary);
                            break;
                    }
                    break;
                case GM_MIXED:
                    switch (next_mode) {
                        case GM_CHINESE: bin_append(1009, 10, binary);
                            break;
                        case GM_NUMBER: bin_append(1010, 10, binary);
                            break;
                        case GM_LOWER: bin_append(1011, 10, binary);
                            break;
                        case GM_UPPER: bin_append(1012, 10, binary);
                            break;
                        case GM_BYTE: bin_append(1015, 10, binary);
                            break;
                    }
                    break;
                case GM_BYTE:
                    /* add byte block length indicator */
                    add_byte_count(binary, byte_count_posn, byte_count);
                    byte_count = 0;
                    switch (next_mode) {
                        case GM_CHINESE: bin_append(1, 4, binary);
                            break;
                        case GM_NUMBER: bin_append(2, 4, binary);
                            break;
                        case GM_LOWER: bin_append(3, 4, binary);
                            break;
                        case GM_UPPER: bin_append(4, 4, binary);
                            break;
                        case GM_MIXED: bin_append(5, 4, binary);
                            break;
                    }
                    break;
            }
            if (debug & ZINT_DEBUG_PRINT) {
                switch (next_mode) {
                    case GM_CHINESE: printf("CHIN ");
                        break;
                    case GM_NUMBER: printf("NUMB ");
                        break;
                    case GM_LOWER: printf("LOWR ");
                        break;
                    case GM_UPPER: printf("UPPR ");
                        break;
                    case GM_MIXED: printf("MIXD ");
                        break;
                    case GM_BYTE: printf("BYTE ");
                        break;
                }
            }
        }
        last_mode = current_mode;
        current_mode = next_mode;

        switch (current_mode) {
            case GM_CHINESE:
                done = 0;
                if (gbdata[sp] > 0xff) {
                    /* GB2312 character */
                    c1 = (gbdata[sp] & 0xff00) >> 8;
                    c2 = gbdata[sp] & 0xff;

                    if ((c1 >= 0xa1) && (c1 <= 0xa9)) {
                        glyph = (0x60 * (c1 - 0xa1)) + (c2 - 0xa0);
                    } else if ((c1 >= 0xb0) && (c1 <= 0xf7)) {
                        glyph = (0x60 * (c1 - 0xb0 + 9)) + (c2 - 0xa0);
                    }
                    done = 1; /* GB 2312 always within above ranges */
                }
                if (!(done)) {
                    if (sp != (length - 1)) {
                        if ((gbdata[sp] == 13) && (gbdata[sp + 1] == 10)) {
                            /* End of Line */
                            glyph = 7776;
                            sp++;
                            done = 1;
                        }
                    }
                }
                if (!(done)) {
                    if (sp != (length - 1)) {
                        if (((gbdata[sp] >= '0') && (gbdata[sp] <= '9')) &&
                                ((gbdata[sp + 1] >= '0') && (gbdata[sp + 1] <= '9'))) {
                            /* Two digits */
                            glyph = 8033 + (10 * (gbdata[sp] - '0')) + (gbdata[sp + 1] - '0');
                            sp++;
                            done = 1;
                        }
                    }
                }
                if (!(done)) {
                    /* Byte value */
                    glyph = 7777 + gbdata[sp];
                }

                if (debug & ZINT_DEBUG_PRINT) {
                    printf("[%d] ", glyph);
                }

                bin_append(glyph, 13, binary);
                sp++;
                break;

            case GM_NUMBER:
                if (last_mode != current_mode) {
                    /* Reserve a space for numeric digit padding value (2 bits) */
                    number_pad_posn = strlen(binary);
                    strcat(binary, "XX");
                }
                p = 0;
                ppos = -1;

                /* Numeric compression can also include certain combinations of
                   non-numeric character */

                numbuf[0] = '0';
                numbuf[1] = '0';
                numbuf[2] = '0';
                do {
                    if ((gbdata[sp] >= '0') && (gbdata[sp] <= '9')) {
                        numbuf[p] = gbdata[sp];
                        p++;
                    } else if (strchr(numeral_nondigits, gbdata[sp])) {
                        if (ppos != -1) {
                            break;
                        }
                        punt = gbdata[sp];
                        ppos = p;
                    } else if (sp < (length - 1) && (gbdata[sp] == 13) && (gbdata[sp + 1] == 10)) {
                        /* <end of line> */
                        if (ppos != -1) {
                            break;
                        }
                        punt = gbdata[sp];
                        sp++;
                        ppos = p;
                    } else {
                        break;
                    }
                    sp++;
                } while ((p < 3) && (sp < length) && mode[sp] == GM_NUMBER);

                if (ppos != -1) {
                    switch (punt) {
                        case ' ': glyph = 0;
                            break;
                        case '+': glyph = 3;
                            break;
                        case '-': glyph = 6;
                            break;
                        case '.': glyph = 9;
                            break;
                        case ',': glyph = 12;
                            break;
                        case 13: glyph = 15;
                            break;
                    }
                    glyph += ppos;
                    glyph += 1000;

                    if (debug & ZINT_DEBUG_PRINT) {
                        printf("[%d] ", glyph);
                    }

                    bin_append(glyph, 10, binary);
                }

                glyph = (100 * (numbuf[0] - '0')) + (10 * (numbuf[1] - '0')) + (numbuf[2] - '0');
                if (debug & ZINT_DEBUG_PRINT) {
                    printf("[%d] ", glyph);
                }

                bin_append(glyph, 10, binary);
                break;

            case GM_BYTE:
                if (last_mode != current_mode) {
                    /* Reserve space for byte block length indicator (9 bits) */
                    byte_count_posn = strlen(binary);
                    strcat(binary, "LLLLLLLLL");
                }
                glyph = gbdata[sp];
                if (byte_count == 512 || (glyph > 0xFF && byte_count == 511)) {
                    /* Maximum byte block size is 512 bytes. If longer is needed then start a new block */
                    if (glyph > 0xFF && byte_count == 511) { /* Split double-byte */
                        bin_append(glyph >> 8, 8, binary);
                        glyph &= 0xFF;
                        byte_count++;
                    }
                    add_byte_count(binary, byte_count_posn, byte_count);
                    bin_append(7, 4, binary);
                    byte_count_posn = strlen(binary);
                    strcat(binary, "LLLLLLLLL");
                    byte_count = 0;
                }

                if (debug & ZINT_DEBUG_PRINT) {
                    printf("[%d] ", glyph);
                }
                bin_append(glyph, glyph > 0xFF ? 16 : 8, binary);
                sp++;
                byte_count++;
                if (glyph > 0xFF) {
                    byte_count++;
                }
                break;

            case GM_MIXED:
                shift = 1;
                if ((gbdata[sp] >= '0') && (gbdata[sp] <= '9')) {
                    shift = 0;
                }
                if ((gbdata[sp] >= 'A') && (gbdata[sp] <= 'Z')) {
                    shift = 0;
                }
                if ((gbdata[sp] >= 'a') && (gbdata[sp] <= 'z')) {
                    shift = 0;
                }
                if (gbdata[sp] == ' ') {
                    shift = 0;
                }

                if (shift == 0) {
                    /* Mixed Mode character */
                    glyph = posn(EUROPIUM, gbdata[sp]);
                    if (debug & ZINT_DEBUG_PRINT) {
                        printf("[%d] ", glyph);
                    }

                    bin_append(glyph, 6, binary);
                } else {
                    /* Shift Mode character */
                    bin_append(1014, 10, binary); /* shift indicator */
                    add_shift_char(binary, gbdata[sp], debug);
                }

                sp++;
                break;

            case GM_UPPER:
                shift = 1;
                if ((gbdata[sp] >= 'A') && (gbdata[sp] <= 'Z')) {
                    shift = 0;
                }
                if (gbdata[sp] == ' ') {
                    shift = 0;
                }

                if (shift == 0) {
                    /* Upper Case character */
                    glyph = posn("ABCDEFGHIJKLMNOPQRSTUVWXYZ ", gbdata[sp]);
                    if (debug & ZINT_DEBUG_PRINT) {
                        printf("[%d] ", glyph);
                    }

                    bin_append(glyph, 5, binary);
                } else {
                    /* Shift Mode character */
                    bin_append(125, 7, binary); /* shift indicator */
                    add_shift_char(binary, gbdata[sp], debug);
                }

                sp++;
                break;

            case GM_LOWER:
                shift = 1;
                if ((gbdata[sp] >= 'a') && (gbdata[sp] <= 'z')) {
                    shift = 0;
                }
                if (gbdata[sp] == ' ') {
                    shift = 0;
                }

                if (shift == 0) {
                    /* Lower Case character */
                    glyph = posn("abcdefghijklmnopqrstuvwxyz ", gbdata[sp]);
                    if (debug & ZINT_DEBUG_PRINT) {
                        printf("[%d] ", glyph);
                    }

                    bin_append(glyph, 5, binary);
                } else {
                    /* Shift Mode character */
                    bin_append(125, 7, binary); /* shift indicator */
                    add_shift_char(binary, gbdata[sp], debug);
                }

                sp++;
                break;
        }
        if (strlen(binary) > 9191) {
            return ZINT_ERROR_TOO_LONG;
        }

    } while (sp < length);

    if (current_mode == GM_NUMBER) {
        /* add numeric block padding value */
        switch (p) {
            case 1: binary[number_pad_posn] = '1';
                binary[number_pad_posn + 1] = '0';
                break; // 2 pad digits
            case 2: binary[number_pad_posn] = '0';
                binary[number_pad_posn + 1] = '1';
                break; // 1 pad digit
            case 3: binary[number_pad_posn] = '0';
                binary[number_pad_posn + 1] = '0';
                break; // 0 pad digits
        }
    }

    if (current_mode == GM_BYTE) {
        /* Add byte block length indicator */
        add_byte_count(binary, byte_count_posn, byte_count);
    }

    /* Add "end of data" character */
    switch (current_mode) {
        case GM_CHINESE: bin_append(8160, 13, binary);
            break;
        case GM_NUMBER: bin_append(1018, 10, binary);
            break;
        case GM_LOWER:
        case GM_UPPER: bin_append(27, 5, binary);
            break;
        case GM_MIXED: bin_append(1008, 10, binary);
            break;
        case GM_BYTE: bin_append(0, 4, binary);
            break;
    }

    /* Add padding bits if required */
    p = 7 - (strlen(binary) % 7);
    if (p % 7) {
        bin_append(0, p, binary);
    }

    if (strlen(binary) > 9191) {
        return ZINT_ERROR_TOO_LONG;
    }
    return 0;
}

static void gm_add_ecc(const char binary[], const size_t data_posn, const int layers, const int ecc_level, unsigned char word[]) {
    int data_cw, i, j, wp, p;
    int n1, b1, n2, b2, e1, b3, e2;
    int block_size, ecc_size;
    unsigned char data[1320], block[130];
    unsigned char data_block[115], ecc_block[70];

    data_cw = gm_data_codewords[((layers - 1) * 5) + (ecc_level - 1)];

    for (i = 0; i < 1320; i++) {
        data[i] = 0;
    }

    /* Convert from binary stream to 7-bit codewords */
    for (i = 0; i < (int) data_posn; i++) {
        for (p = 0; p < 7; p++) {
            if (binary[i * 7 + p] == '1') {
                data[i] += (0x40 >> p);
            }
        }
    }

    /* Add padding codewords */
    data[data_posn] = 0x00;
    for (i = (int) (data_posn + 1); i < data_cw; i++) {
        if (i & 1) {
            data[i] = 0x7e;
        } else {
            data[i] = 0x00;
        }
    }

    /* Get block sizes */
    n1 = gm_n1[(layers - 1)];
    b1 = gm_b1[(layers - 1)];
    n2 = n1 - 1;
    b2 = gm_b2[(layers - 1)];
    e1 = gm_ebeb[((layers - 1) * 20) + ((ecc_level - 1) * 4)];
    b3 = gm_ebeb[((layers - 1) * 20) + ((ecc_level - 1) * 4) + 1];
    e2 = gm_ebeb[((layers - 1) * 20) + ((ecc_level - 1) * 4) + 2];

    /* Split the data into blocks */
    wp = 0;
    for (i = 0; i < (b1 + b2); i++) {
        int data_size;
        if (i < b1) {
            block_size = n1;
        } else {
            block_size = n2;
        }
        if (i < b3) {
            ecc_size = e1;
        } else {
            ecc_size = e2;
        }
        data_size = block_size - ecc_size;

        /* printf("block %d/%d: data %d / ecc %d\n", i + 1, (b1 + b2), data_size, ecc_size);*/

        for (j = 0; j < data_size; j++) {
            data_block[j] = data[wp];
            wp++;
        }

        /* Calculate ECC data for this block */
        rs_init_gf(0x89);
        rs_init_code(ecc_size, 1);
        rs_encode(data_size, data_block, ecc_block);
        rs_free();

        /* Correct error correction data but in reverse order */
        for (j = 0; j < data_size; j++) {
            block[j] = data_block[j];
        }
        for (j = 0; j < ecc_size; j++) {
            block[(j + data_size)] = ecc_block[ecc_size - j - 1];
        }

        for (j = 0; j < n2; j++) {
            word[((b1 + b2) * j) + i] = block[j];
        }
        if (block_size == n1) {
            word[((b1 + b2) * (n1 - 1)) + i] = block[(n1 - 1)];
        }
    }
}

static void place_macromodule(char grid[], int x, int y, int word1, int word2, int size) {
    int i, j;

    i = (x * 6) + 1;
    j = (y * 6) + 1;

    if (word2 & 0x40) {
        grid[(j * size) + i + 2] = '1';
    }
    if (word2 & 0x20) {
        grid[(j * size) + i + 3] = '1';
    }
    if (word2 & 0x10) {
        grid[((j + 1) * size) + i] = '1';
    }
    if (word2 & 0x08) {
        grid[((j + 1) * size) + i + 1] = '1';
    }
    if (word2 & 0x04) {
        grid[((j + 1) * size) + i + 2] = '1';
    }
    if (word2 & 0x02) {
        grid[((j + 1) * size) + i + 3] = '1';
    }
    if (word2 & 0x01) {
        grid[((j + 2) * size) + i] = '1';
    }
    if (word1 & 0x40) {
        grid[((j + 2) * size) + i + 1] = '1';
    }
    if (word1 & 0x20) {
        grid[((j + 2) * size) + i + 2] = '1';
    }
    if (word1 & 0x10) {
        grid[((j + 2) * size) + i + 3] = '1';
    }
    if (word1 & 0x08) {
        grid[((j + 3) * size) + i] = '1';
    }
    if (word1 & 0x04) {
        grid[((j + 3) * size) + i + 1] = '1';
    }
    if (word1 & 0x02) {
        grid[((j + 3) * size) + i + 2] = '1';
    }
    if (word1 & 0x01) {
        grid[((j + 3) * size) + i + 3] = '1';
    }
}

static void place_data_in_grid(unsigned char word[], char grid[], int modules, int size) {
    int x, y, macromodule, offset;

    offset = 13 - ((modules - 1) / 2);
    for (y = 0; y < modules; y++) {
        for (x = 0; x < modules; x++) {
            macromodule = gm_macro_matrix[((y + offset) * 27) + (x + offset)];
            place_macromodule(grid, x, y, word[macromodule * 2], word[(macromodule * 2) + 1], size);
        }
    }
}

/* Place the layer ID into each macromodule */
static void place_layer_id(char* grid, int size, int layers, int modules, int ecc_level) {
    int i, j, layer, start, stop;

#ifndef _MSC_VER
    int layerid[layers + 1];
    int id[modules * modules];
#else
    int* layerid = (int *) _alloca((layers + 1) * sizeof (int));
    int* id = (int *) _alloca((modules * modules) * sizeof (int));
#endif

    /* Calculate Layer IDs */
    for (i = 0; i <= layers; i++) {
        if (ecc_level == 1) {
            layerid[i] = 3 - (i % 4);
        } else {
            layerid[i] = (i + 5 - ecc_level) % 4;
        }
    }

    for (i = 0; i < modules; i++) {
        for (j = 0; j < modules; j++) {
            id[(i * modules) + j] = 0;
        }
    }

    /* Calculate which value goes in each macromodule */
    start = modules / 2;
    stop = modules / 2;
    for (layer = 0; layer <= layers; layer++) {
        for (i = start; i <= stop; i++) {
            id[(start * modules) + i] = layerid[layer];
            id[(i * modules) + start] = layerid[layer];
            id[((modules - start - 1) * modules) + i] = layerid[layer];
            id[(i * modules) + (modules - start - 1)] = layerid[layer];
        }
        start--;
        stop++;
    }

    /* Place the data in the grid */
    for (i = 0; i < modules; i++) {
        for (j = 0; j < modules; j++) {
            if (id[(i * modules) + j] & 0x02) {
                grid[(((i * 6) + 1) * size) + (j * 6) + 1] = '1';
            }
            if (id[(i * modules) + j] & 0x01) {
                grid[(((i * 6) + 1) * size) + (j * 6) + 2] = '1';
            }
        }
    }
}

INTERNAL int grid_matrix(struct zint_symbol *symbol, const unsigned char source[], size_t length) {
    int size, modules, error_number;
    int auto_layers, min_layers, layers, auto_ecc_level, min_ecc_level, ecc_level;
    int x, y, i;
    int full_multibyte;
    char binary[9300];
    int data_cw, input_latch = 0;
    unsigned char word[1460];
    int data_max, reader = 0;

#ifndef _MSC_VER
    unsigned int gbdata[length + 1];
#else
    char* grid;
    unsigned int* gbdata = (unsigned int *) _alloca((length + 1) * sizeof (unsigned int));
#endif

    for (i = 0; i < 1460; i++) {
        word[i] = 0;
    }

    full_multibyte = symbol->option_3 == ZINT_FULL_MULTIBYTE; /* If set use Hanzi mode in DATA_MODE or for single-byte Latin */

    if ((symbol->input_mode & 0x07) == DATA_MODE) {
        gb2312_cpy(source, &length, gbdata, full_multibyte);
    } else {
        int done = 0;
        if (symbol->eci != 29) { /* Unless ECI 29 (GB) */
            /* Try single byte (Latin) conversion first */
            int error_number = gb2312_utf8tosb(symbol->eci && symbol->eci <= 899 ? symbol->eci : 3, source, &length, gbdata, full_multibyte);
            if (error_number == 0) {
                done = 1;
            } else if (symbol->eci && symbol->eci <= 899) {
                strcpy(symbol->errtxt, "575: Invalid characters in input data");
                return error_number;
            }
        }
        if (!done) {
            /* Try GB 2312 (EUC-CN) */
            int error_number = gb2312_utf8tomb(symbol, source, &length, gbdata);
            if (error_number != 0) {
                return error_number;
            }
        }
    }

    if (symbol->output_options & READER_INIT) reader = 1;

    if (symbol->eci > 811799) {
        strcpy(symbol->errtxt, "533: Invalid ECI");
        return ZINT_ERROR_INVALID_OPTION;
    }

    error_number = gm_encode(gbdata, length, binary, reader, symbol->eci, symbol->debug);
    if (error_number != 0) {
        strcpy(symbol->errtxt, "531: Input data too long");
        return error_number;
    }

    /* Determine the size of the symbol */
    data_cw = (int)strlen(binary) / 7;

    auto_layers = 13;
    for (i = 12; i > 0; i--) {
        if (gm_recommend_cw[(i - 1)] >= data_cw) {
            auto_layers = i;
        }
    }
    min_layers = 13;
    for (i = 12; i > 0; i--) {
        if (gm_max_cw[(i - 1)] >= data_cw) {
            min_layers = i;
        }
    }
    layers = auto_layers;

    if ((symbol->option_2 >= 1) && (symbol->option_2 <= 13)) {
        input_latch = 1;
        if (symbol->option_2 >= min_layers) {
            layers = symbol->option_2;
        } else {
            strcpy(symbol->errtxt, "534: Input data too long for selected symbol size");
            return ZINT_ERROR_TOO_LONG;
        }
    }

    auto_ecc_level = 3;
    if (layers == 1) {
        auto_ecc_level = 5;
    }
    if ((layers == 2) || (layers == 3)) {
        auto_ecc_level = 4;
    }
    ecc_level = auto_ecc_level;

    min_ecc_level = 1;
    if (layers == 1) {
        min_ecc_level = 4;
    }
    if (layers == 2) {
        min_ecc_level = 2;
    }

    if ((symbol->option_1 >= 1) && (symbol->option_1 <= 5)) {
        if (symbol->option_1 >= min_ecc_level) {
            ecc_level = symbol->option_1;
        } else {
            ecc_level = min_ecc_level;
        }
    }
    if (data_cw > gm_data_codewords[(5 * (layers - 1)) + (ecc_level - 1)]) {
        if (input_latch && ecc_level > min_ecc_level) { /* If layers user-specified (option_2), try reducing ECC level first */
            do {
                ecc_level--;
            } while ((data_cw > gm_data_codewords[(5 * (layers - 1)) + (ecc_level - 1)]) && (ecc_level > min_ecc_level));
        }
        while (data_cw > gm_data_codewords[(5 * (layers - 1)) + (ecc_level - 1)] && (layers < 13)) {
            layers++;
        }
        while (data_cw > gm_data_codewords[(5 * (layers - 1)) + (ecc_level - 1)] && ecc_level > 1) { /* ECC min level 1 for layers > 2 */
            ecc_level--;
        }
    }

    data_max = 1313;
    switch (ecc_level) {
        case 2: data_max = 1167;
            break;
        case 3: data_max = 1021;
            break;
        case 4: data_max = 875;
            break;
        case 5: data_max = 729;
            break;
    }

    if (data_cw > data_max) {
        strcpy(symbol->errtxt, "532: Input data too long");
        return ZINT_ERROR_TOO_LONG;
    }

    gm_add_ecc(binary, data_cw, layers, ecc_level, word);
#ifdef ZINT_TEST
    if (symbol->debug & ZINT_DEBUG_TEST) debug_test_codeword_dump(symbol, word, data_cw);
#endif
    size = 6 + (layers * 12);
    modules = 1 + (layers * 2);

#ifndef _MSC_VER
    char grid[size * size];
#else
    grid = (char *) _alloca((size * size) * sizeof (char));
#endif

    for (x = 0; x < size; x++) {
        for (y = 0; y < size; y++) {
            grid[(y * size) + x] = '0';
        }
    }

    place_data_in_grid(word, grid, modules, size);
    place_layer_id(grid, size, layers, modules, ecc_level);

    /* Add macromodule frames */
    for (x = 0; x < modules; x++) {
        int dark = 1 - (x & 1);
        for (y = 0; y < modules; y++) {
            if (dark == 1) {
                for (i = 0; i < 5; i++) {
                    grid[((y * 6) * size) + (x * 6) + i] = '1';
                    grid[(((y * 6) + 5) * size) + (x * 6) + i] = '1';
                    grid[(((y * 6) + i) * size) + (x * 6)] = '1';
                    grid[(((y * 6) + i) * size) + (x * 6) + 5] = '1';
                }
                grid[(((y * 6) + 5) * size) + (x * 6) + 5] = '1';
                dark = 0;
            } else {
                dark = 1;
            }
        }
    }

    /* Copy values to symbol */
    symbol->width = size;
    symbol->rows = size;

    for (x = 0; x < size; x++) {
        for (y = 0; y < size; y++) {
            if (grid[(y * size) + x] == '1') {
                set_module(symbol, y, x);
            }
        }
        symbol->row_height[x] = 1;
    }

    return 0;
}