/* aztec.c - Handles Aztec 2D Symbols */

/*
    libzint - the open source barcode library
    Copyright (C) 2009-2017 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.
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#ifdef _MSC_VER
#include <malloc.h> 
#endif
#include "common.h"
#include "aztec.h"
#include "reedsol.h"

static int AztecMap[22801];

static int count_doubles(const unsigned char source[], const int posn, const size_t src_len) {
    int c = 0;
    int i = posn;
    int cond = 1;
    
    do {
        if (((source[i] == '.') || (source[i] == ',')) && (source[i + 1] == ' ')) {
            c++;
        } else {
            cond = 0;
        }
        i += 2;
    } while ((i < src_len) && cond);

    return c;
}

static int count_cr(char source[], int posn, int length) {
    int c = 0;
    int i = posn;
    int cond = 1;
    
    do {
        if (source[i] == 13) {
            c++;
        } else {
            cond = 0;
        }
        i++;
    } while ((i < length) && cond);
    
    return c;
}

static int count_dotcomma(char source[], int posn, int length) {
    int c = 0;
    int i = posn;
    int cond = 1;
    
    do {
        if ((source[i] == '.') || (source[i] == ',')) {
            c++;
        } else {
            cond = 0;
        }
        i++;
    } while ((i < length) && cond);
    
    return c;
}

static int count_spaces(char source[], int posn, int length) {
    int c = 0;
    int i = posn;
    int cond = 1;
    
    do {
        if (source[i] == ' ') {
            c++;
        } else {
            cond = 0;
        }
        i++;
    } while ((i < length) && cond);
    
    return c;
}

static char get_next_mode(char encode_mode[], const size_t src_len, const int posn) {
    int i = posn;
    
    do {
        i++;
    } while ((i < src_len) && (encode_mode[i] == encode_mode[posn]));
    if (i >= src_len) {
        return 'E';
    } else {
        return encode_mode[i];
    }
}

static int aztec_text_process(const unsigned char source[], const size_t src_len, char binary_string[], const int gs1, const int eci, const int debug) {
    
    char *encode_mode;
    int i, j;
    char current_mode;
    int count;
    char next_mode;
    char *reduced_source;
    char *reduced_encode_mode;
    int reduced_length;
    int byte_mode = 0;
    
    encode_mode=(char*)alloca(src_len);
    reduced_source=(char*)alloca(src_len);
    reduced_encode_mode=(char*)alloca(src_len);

    if ((!encode_mode) ||
        (!reduced_source) ||
        (!reduced_encode_mode)) return -1;

    for (i = 0; i < src_len; i++) {
        if (source[i] > 128) {
            encode_mode[i] = 'B';
        } else {
            encode_mode[i] = AztecModes[(int) source[i]];
        }
    }
    
    // Deal first with letter combinations which can be combined to one codeword
    // Combinations are (CR LF) (. SP) (, SP) (: SP) in Punct mode
    current_mode = 'U';
    for (i = 0; i < src_len - 1; i++) {
        // Combination (CR LF) should always be in Punct mode
        if ((source[i] == 13) && (source[i + 1] == 10)) {
            encode_mode[i] = 'P';
            encode_mode[i + 1] = 'P';
        }
        
        // Combination (: SP) should always be in Punct mode
        if ((source[i] == ':') && (source[i + 1] == ' ')) {
            encode_mode[i + 1] = 'P';
        }
        
        // Combinations (. SP) and (, SP) sometimes use fewer bits in Digit mode
        if (((source[i] == '.') || (source[i] == ',')) && (source[i + 1] == ' ') && (encode_mode[i] == 'X')) {
            count = count_doubles(source, i, src_len);
            next_mode = get_next_mode(encode_mode, src_len, i);
            
            if (current_mode == 'U') {
                if ((next_mode == 'D') && (count <= 5)) {
                    for (j = 0; j < (2 * count); j++) {
                        encode_mode[i + j] = 'D';
                    }
                }
            }
            
            if (current_mode == 'L') {
                if ((next_mode == 'U') && (count == 1)) {
                    encode_mode[i] = 'D';
                    encode_mode[i + 1] = 'D';
                }
                if ((next_mode == 'D') && (count <= 4)) {
                    for (j = 0; j < (2 * count); j++) {
                        encode_mode[i + j] = 'D';
                    }
                }
            }
            
            if (current_mode == 'M') {
                if ((next_mode == 'D') && (count == 1)) {
                    encode_mode[i] = 'D';
                    encode_mode[i + 1] = 'D';
                }
            }
            
            if (current_mode == 'D') {
                if ((next_mode != 'D') && (count <= 4)) {
                    for (j = 0; j < (2 * count); j++) {
                        encode_mode[i + j] = 'D';
                    }
                }
                if ((next_mode == 'D') && (count <= 7)) {
                    for (j = 0; j < (2 * count); j++) {
                        encode_mode[i + j] = 'D';
                    }
                }
            }
            
            // Default is Punct mode
            if (encode_mode[i] == 'X') {
                encode_mode[i] = 'P';
                encode_mode[i + 1] = 'P';
            }
        }
        
        if ((encode_mode[i] != 'X') && (encode_mode[i] != 'B')) {
            current_mode = encode_mode[i];
        }
    }
    
    if (debug) {
        printf("First Pass:\n");
        for (i = 0; i < src_len; i++) {
            printf("%c", encode_mode[i]);
        }
        printf("\n");
    }
    
    // Reduce two letter combinations to one codeword marked as [abcd] in Punct mode
    i = 0;
    j = 0;
    do {
        if ((source[i] == 13) && (source[i + 1] == 10)) { // CR LF
            reduced_source[j] = 'a';
            reduced_encode_mode[j] = encode_mode[i];
            i += 2;
        } else if (((source[i] == '.') && (source[i + 1] == ' ')) && (encode_mode[i] == 'P')) {
            reduced_source[j] = 'b';
            reduced_encode_mode[j] = encode_mode[i];
            i += 2;
        } else if (((source[i] == ',') && (source[i + 1] == ' ')) && (encode_mode[i] == 'P')) {
            reduced_source[j] = 'c';
            reduced_encode_mode[j] = encode_mode[i];
            i += 2;
        } else if ((source[i] == ':') && (source[i + 1] == ' ')) {
            reduced_source[j] = 'd';
            reduced_encode_mode[j] = encode_mode[i];
            i += 2;
        } else {
            reduced_source[j] = source[i];
            reduced_encode_mode[j] = encode_mode[i];
            i++;
        }
        j++;
    } while (i < src_len);
    
    reduced_length = j;
    
    current_mode = 'U';
    for(i = 0; i < reduced_length; i++) {
        
        // Resolve Carriage Return (CR) which can be Punct or Mixed mode
        if (reduced_source[i] == 13) {
            count = count_cr(reduced_source, i, reduced_length);
            next_mode = get_next_mode(reduced_encode_mode, reduced_length, i);
            
            if ((current_mode == 'U') && ((next_mode == 'U') || (next_mode == 'B')) && (count == 1)) {
                reduced_encode_mode[i] = 'P';
            }
            
            if ((current_mode == 'L') && ((next_mode == 'L') || (next_mode == 'B')) && (count == 1)) {
                reduced_encode_mode[i] = 'P';
            }
            
            if ((current_mode == 'P') || (next_mode == 'P')) {
                reduced_encode_mode[i] = 'P';
            }
            
            if (current_mode == 'D') {
                if (((next_mode == 'E') || (next_mode == 'U') || (next_mode == 'D') || (next_mode == 'B')) && (count <= 2)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'P';
                    }
                }
                if ((next_mode == 'L') && (count == 1)) {
                    reduced_encode_mode[i] = 'P';
                }
            }
            
            // Default is Mixed mode
            if (reduced_encode_mode[i] == 'X') {
                reduced_encode_mode[i] = 'M';
            }
        }
        
        // Resolve full stop and comma which can be in Punct or Digit mode
        if ((reduced_source[i] == '.') || (reduced_source[i] == ',')) {
            count = count_dotcomma(reduced_source, i, reduced_length);
            next_mode = get_next_mode(reduced_encode_mode, reduced_length, i);
            
            if (current_mode == 'U') {
                if (((next_mode == 'U') || (next_mode == 'L') || (next_mode == 'M') || (next_mode == 'B')) && (count == 1)) {
                    reduced_encode_mode[i] = 'P';
                }
            }
            
            if (current_mode == 'L') {
                if ((next_mode == 'L') && (count <= 2)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'P';
                    }
                }
                if (((next_mode == 'M') || (next_mode == 'B')) && (count == 1)) {
                    reduced_encode_mode[i] = 'P';
                }
            }
            
            if (current_mode == 'M') {
                if (((next_mode == 'E') || (next_mode == 'U') || (next_mode == 'L') || (next_mode == 'M')) && (count <= 4)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'P';
                    }
                }
                if ((next_mode == 'B') && (count <= 2)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'P';
                    }
                }
            }
            
            if ((current_mode == 'P') && (next_mode != 'D') && (count <= 9)) {
                for (j = 0; j < count; j++) {
                    reduced_encode_mode[i + j] = 'P';
                }
            }
            
            // Default is Digit mode
            if (reduced_encode_mode[i] == 'X') {
                reduced_encode_mode[i] = 'D';
            }
        }
        
        // Resolve Space (SP) which can be any mode except Punct
        if (reduced_source[i] == ' ') {
            count = count_spaces(reduced_source, i, reduced_length);
            next_mode = get_next_mode(reduced_encode_mode, reduced_length, i);
            
            if (current_mode == 'U') {
                if ((next_mode == 'E') && (count <= 5)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'U';
                    }
                }
                if (((next_mode == 'U') || (next_mode == 'L') || (next_mode == 'M') || (next_mode == 'P') || (next_mode == 'B')) && (count <= 9)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'U';
                    }
                }
            }
            
            if (current_mode == 'L') {
                if ((next_mode == 'E') && (count <= 5)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'L';
                    }
                }
                if ((next_mode == 'U') && (count == 1)) {
                    reduced_encode_mode[i] = 'L';
                }
                if ((next_mode == 'L') && (count <= 14)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'L';
                    }
                }
                if (((next_mode == 'M') || (next_mode == 'P') || (next_mode == 'B')) && (count <= 9)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'L';
                    }
                }
            }
            
            if (current_mode == 'M') {
                if (((next_mode == 'E') || (next_mode == 'U')) && (count <= 9)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'M';
                    }
                }
                
                if (((next_mode == 'L') || (next_mode == 'B')) && (count <= 14)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'M';
                    }
                }
                
                if (((next_mode == 'M') || (next_mode == 'P')) && (count <= 19)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'M';
                    }
                }
            }
            
            if (current_mode == 'P') {
                if ((next_mode == 'E') && (count <= 5)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'U';
                    }
                }
                
                if (((next_mode == 'U') || (next_mode == 'L') || (next_mode == 'M') || (next_mode == 'P') || (next_mode == 'B')) && (count <= 9)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'U';
                    }
                }
            }
            
            // Default is Digit mode
            if (reduced_encode_mode[i] == 'X') {
                reduced_encode_mode[i] = 'D';
            }
        }
        
        if (reduced_encode_mode[i] != 'B') {
            current_mode = reduced_encode_mode[i];
        }
    }
    
    // Decide when to use P/S instead of P/L and U/S instead of U/L
    current_mode = 'U';
    for(i = 0; i < reduced_length; i++) {
        
        if (reduced_encode_mode[i] != current_mode) {

            for (count = 0; ((i + count) <= reduced_length) && (reduced_encode_mode[i + count] == reduced_encode_mode[i]); count++);
            next_mode = get_next_mode(reduced_encode_mode, reduced_length, i);
            
            if (reduced_encode_mode[i] == 'P') {
                if ((current_mode == 'U') && (count <= 2)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'p';
                    }
                }
                
                if ((current_mode == 'L') && (next_mode != 'U') && (count <= 2)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'p';
                    }
                }
                
                if ((current_mode == 'L') && (next_mode == 'U') && (count == 1)) {
                    reduced_encode_mode[i] = 'p';
                }
                
                if ((current_mode == 'M') && (next_mode != 'M') && (count == 1)) {
                    reduced_encode_mode[i] = 'p';
                }
                
                if ((current_mode == 'M') && (next_mode == 'M') && (count <= 2)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'p';
                    }
                }
                
                if ((current_mode == 'D') && (next_mode != 'D') && (count <= 3)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'p';
                    }
                }
                
                if ((current_mode == 'D') && (next_mode == 'D') && (count <= 6)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'p';
                    }
                }
            }
            
            if (reduced_encode_mode[i] == 'U') {
                if ((current_mode == 'L') && ((next_mode == 'L') || (next_mode == 'M')) && (count <= 2)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'u';
                    }
                }
                
                if ((current_mode == 'L') && ((next_mode == 'E') || (next_mode == 'D') || (next_mode == 'B') || (next_mode == 'P')) && (count == 1)) {
                    reduced_encode_mode[i] = 'u';
                }
                
                if ((current_mode == 'D') && (next_mode == 'D') && (count == 1)) {
                    reduced_encode_mode[i] = 'u';
                }
                
                if ((current_mode == 'D') && (next_mode == 'P') && (count <= 2)) {
                    for (j = 0; j < count; j++) {
                        reduced_encode_mode[i + j] = 'u';
                    }
                }
            }
        }
        
        if ((reduced_encode_mode[i] != 'p') && (reduced_encode_mode[i] != 'u') && (reduced_encode_mode[i] != 'B')) {
            current_mode = reduced_encode_mode[i];
        }
    }

    if (debug) {
        for (i = 0; i < reduced_length; i++) {
            printf("%c", reduced_source[i]);
        }
        printf("\n");
        for (i = 0; i < reduced_length; i++) {
            printf("%c", reduced_encode_mode[i]);
        }
        printf("\n");
    }
    
    strcpy(binary_string, "");
    
    if (gs1) {
        bin_append(0, 5, binary_string); // P/S
        bin_append(0, 5, binary_string); // FLG(n)
        bin_append(0, 3, binary_string); // FLG(0)
    }

    if (eci != 3) {
        bin_append(0, 5, binary_string); // P/S
        bin_append(0, 5, binary_string); // FLG(n)
        if (eci < 10) {
            bin_append(1, 3, binary_string); // FLG(1)
            bin_append(2 + eci, 4, binary_string);
        }
        if ((eci >= 10) && (eci <= 99)) {
            bin_append(2, 3, binary_string); // FLG(2)
            bin_append(2 + (eci / 10), 4, binary_string);
            bin_append(2 + (eci % 10), 4, binary_string);
        }
        if ((eci >= 100) && (eci <= 999)) {
            bin_append(3, 3, binary_string); // FLG(3)
            bin_append(2 + (eci / 100), 4, binary_string);
            bin_append(2 + ((eci % 100) / 10), 4, binary_string);
            bin_append(2 + (eci % 10), 4, binary_string);
        }
        if ((eci >= 1000) && (eci <= 9999)) {
            bin_append(4, 3, binary_string); // FLG(4)
            bin_append(2 + (eci / 1000), 4, binary_string);
            bin_append(2 + ((eci % 1000) / 100), 4, binary_string);
            bin_append(2 + ((eci % 100) / 10), 4, binary_string);
            bin_append(2 + (eci % 10), 4, binary_string);
        }
        if ((eci >= 10000) && (eci <= 99999)) {
            bin_append(5, 3, binary_string); // FLG(5)
            bin_append(2 + (eci / 10000), 4, binary_string);
            bin_append(2 + ((eci % 10000) / 1000), 4, binary_string);
            bin_append(2 + ((eci % 1000) / 100), 4, binary_string);
            bin_append(2 + ((eci % 100) / 10), 4, binary_string);
            bin_append(2 + (eci % 10), 4, binary_string);
        }
        if (eci >= 100000) {
            bin_append(6, 3, binary_string); // FLG(6)
            bin_append(2 + (eci / 100000), 4, binary_string);
            bin_append(2 + ((eci % 100000) / 10000), 4, binary_string);
            bin_append(2 + ((eci % 10000) / 1000), 4, binary_string);
            bin_append(2 + ((eci % 1000) / 100), 4, binary_string);
            bin_append(2 + ((eci % 100) / 10), 4, binary_string);
            bin_append(2 + (eci % 10), 4, binary_string);
        }
    }

    current_mode = 'U';
    for(i = 0; i < reduced_length; i++) {
        if (reduced_encode_mode[i] != current_mode) {
            // Change mode
            if (current_mode == 'U') {
                switch (reduced_encode_mode[i]) {
                    case 'L':
                        bin_append(28, 5, binary_string); // L/L
                        break;
                    case 'M':
                        bin_append(29, 5, binary_string); // M/L
                        break;
                    case 'P':
                        bin_append(29, 5, binary_string); // M/L
                        bin_append(30, 5, binary_string); // P/L
                        break;
                    case 'p':
                        bin_append(0, 5, binary_string); // P/S
                        break;
                    case 'D':
                        bin_append(30, 5, binary_string); // D/L
                        break;
                    case 'B':
                        bin_append(31, 5, binary_string); // B/S
                        break;
                }
            }
            
            if (current_mode == 'L') {
                switch (reduced_encode_mode[i]) {
                    case 'U':
                        bin_append(30, 5, binary_string); // D/L
                        bin_append(14, 4, binary_string); // U/L
                        break;
                    case 'u':
                        bin_append(28, 5, binary_string); // U/S
                        break;
                    case 'M':
                        bin_append(29, 5, binary_string); // M/L
                        break;
                    case 'P':
                        bin_append(30, 5, binary_string); // P/L
                        break;
                    case 'p':
                        bin_append(0, 5, binary_string); // P/S
                        break;
                    case 'D':
                        bin_append(30, 5, binary_string); // D/L
                        break;
                    case 'B':
                        bin_append(31, 5, binary_string); // B/S
                        break;
                }
            }
            
            if (current_mode == 'M') {
                switch (reduced_encode_mode[i]) {
                    case 'U':
                        bin_append(29, 5, binary_string); // U/L
                        break;
                    case 'L':
                        bin_append(28, 5, binary_string); // L/L
                        break;
                    case 'P':
                        bin_append(30, 5, binary_string); // P/L
                        break;
                    case 'p':
                        bin_append(0, 5, binary_string); // P/S
                        break;
                    case 'D':
                        bin_append(29, 5, binary_string); // U/L
                        bin_append(30, 5, binary_string); // D/L
                        break;
                    case 'B':
                        bin_append(31, 5, binary_string); // B/S
                        break;
                }
            }
            
            if (current_mode == 'P') {
                switch (reduced_encode_mode[i]) {
                    case 'U':
                        bin_append(31, 5, binary_string); // U/L
                        break;
                    case 'L':
                        bin_append(31, 5, binary_string); // U/L
                        bin_append(28, 5, binary_string); // L/L
                        break;
                    case 'M':
                        bin_append(31, 5, binary_string); // U/L
                        bin_append(29, 5, binary_string); // M/L
                        break;
                    case 'D':
                        bin_append(31, 5, binary_string); // U/L
                        bin_append(30, 5, binary_string); // D/L
                        break;
                    case 'B':
                        bin_append(31, 5, binary_string); // U/L
                        current_mode = 'U';
                        bin_append(31, 5, binary_string); // B/S
                        break;
                }
            }
                
            if (current_mode == 'D') {
                switch (reduced_encode_mode[i]) {
                    case 'U':
                        bin_append(14, 4, binary_string); // U/L
                        break;
                    case 'u':
                        bin_append(15, 4, binary_string); // U/S
                        break;
                    case 'L':
                        bin_append(14, 4, binary_string); // U/L
                        bin_append(28, 5, binary_string); // L/L
                        break;
                    case 'M':
                        bin_append(14, 4, binary_string); // U/L
                        bin_append(29, 5, binary_string); // M/L
                        break;
                    case 'P':
                        bin_append(14, 4, binary_string); // U/L
                        bin_append(29, 5, binary_string); // M/L
                        bin_append(30, 5, binary_string); // P/L
                        break;
                    case 'p':
                        bin_append(0, 4, binary_string); // P/S
                        break;
                    case 'B':
                        bin_append(14, 4, binary_string); // U/L
                        current_mode = 'U';
                        bin_append(31, 5, binary_string); // B/S
                        break;
                }
            }
                
            // Byte mode length descriptor
            if ((reduced_encode_mode[i] == 'B') && (!byte_mode)) {
                for (count = 0; ((i + count) < reduced_length) && (reduced_encode_mode[i] == 'B'); count++);

                if (count > 2079) {
                    return ZINT_ERROR_TOO_LONG;
                }

                if (count > 31) {
                    /* Put 00000 followed by 11-bit number of bytes less 31 */
                    bin_append(0, 5, binary_string);
                    bin_append(count - 31, 11, binary_string);
                } else {
                    /* Put 5-bit number of bytes */
                    bin_append(count, 5, binary_string);
                }
                byte_mode = 1;
            }

            if ((reduced_encode_mode[i] != 'B') && byte_mode) {
                byte_mode = 0;
            }

            if ((reduced_encode_mode[i] != 'B') && (reduced_encode_mode[i] != 'u') && (reduced_encode_mode[i] != 'p')) {
                current_mode = reduced_encode_mode[i];
            }
        }

        if ((reduced_encode_mode[i] == 'U') || (reduced_encode_mode[i] == 'u')) {
            if (reduced_source[i] == ' ') {
                bin_append(1, 5, binary_string); // SP
            } else {
                bin_append(AztecSymbolChar[(int) reduced_source[i]], 5, binary_string);
            }
        }
        
        if (reduced_encode_mode[i] == 'L') {
            if (reduced_source[i] == ' ') {
                bin_append(1, 5, binary_string); // SP
            } else {
                bin_append(AztecSymbolChar[(int) reduced_source[i]], 5, binary_string);
            }
        }
        
        if (reduced_encode_mode[i] == 'M') {
            if (reduced_source[i] == ' ') {
                bin_append(1, 5, binary_string); // SP
            } else if (reduced_source[i] == 13) {
                bin_append(14, 5, binary_string); // CR
            } else {
                bin_append(AztecSymbolChar[(int) reduced_source[i]], 5, binary_string);
            }
        }
        
        if ((reduced_encode_mode[i] == 'P') || (reduced_encode_mode[i] == 'p')) {
            if (gs1 && (reduced_source[i] == '[')) {
                bin_append(0, 5, binary_string); // FLG(0) = FNC1
            } else if (reduced_source[i] == 13) {
                bin_append(1, 5, binary_string); // CR
            } else if (reduced_source[i] == 'a') {
                bin_append(2, 5, binary_string); // CR LF
            } else if (reduced_source[i] == 'b') {
                bin_append(3, 5, binary_string); // . SP
            } else if (reduced_source[i] == 'c') {
                bin_append(4, 5, binary_string); // , SP
            } else if (reduced_source[i] == 'd') {
                bin_append(5, 5, binary_string); // : SP
            } else if (reduced_source[i] == ',') {
                bin_append(17, 5, binary_string); // Comma
            } else if (reduced_source[i] == '.') {
                bin_append(19, 5, binary_string); // Full stop
            } else {
                bin_append(AztecSymbolChar[(int) reduced_source[i]], 5, binary_string);
            }
        }
        
        if (reduced_encode_mode[i] == 'D') {
            if (reduced_source[i] == ' ') {
                bin_append(1, 4, binary_string); // SP
            } else if (reduced_source[i] == ',') {
                bin_append(12, 4, binary_string); // Comma
            } else if (reduced_source[i] == '.') {
                bin_append(13, 4, binary_string); // Full stop
            } else {
                bin_append(AztecSymbolChar[(int) reduced_source[i]], 4, binary_string);
            }
        }
        
        if (reduced_encode_mode[i] == 'B') {
            bin_append(reduced_source[i], 8, binary_string);
        }
    }
    
    if (debug) {
        printf("Binary String:\n");
        printf("%s\n", binary_string);
    }
    
    return 0;
}

/* Prevent data from obscuring reference grid */
static int avoidReferenceGrid(int output) {

    if (output > 10) {
        output++;
    }
    if (output > 26) {
        output++;
    }
    if (output > 42) {
        output++;
    }
    if (output > 58) {
        output++;
    }
    if (output > 74) {
        output++;
    }
    if (output > 90) {
        output++;
    }
    if (output > 106) {
        output++;
    }
    if (output > 122) {
        output++;
    }
    if (output > 138) {
        output++;
    }

    return output;
}

/* Calculate the position of the bits in the grid */
static void populate_map() {
    int layer, start, length, n, i;
    int x, y;

    for (x = 0; x < 151; x++) {
        for (y = 0; y < 151; y++) {
            AztecMap[(x * 151) + y] = 0;
        }
    }

    for (layer = 1; layer < 33; layer++) {
        start = (112 * (layer - 1)) + (16 * (layer - 1) * (layer - 1)) + 2;
        length = 28 + ((layer - 1) * 4) + (layer * 4);
        /* Top */
        i = 0;
        x = 64 - ((layer - 1) * 2);
        y = 63 - ((layer - 1) * 2);
        for (n = start; n < (start + length); n += 2) {
            AztecMap[(avoidReferenceGrid(x + i) * 151) + avoidReferenceGrid(y)] = n;
            AztecMap[(avoidReferenceGrid(x + i) * 151) + avoidReferenceGrid(y - 1)] = n + 1;
            i++;
        }
        /* Right */
        i = 0;
        x = 78 + ((layer - 1) * 2);
        y = 64 - ((layer - 1) * 2);
        for (n = start + length; n < (start + (length * 2)); n += 2) {
            AztecMap[(avoidReferenceGrid(x) * 151) + avoidReferenceGrid(y + i)] = n;
            AztecMap[(avoidReferenceGrid(x + 1) * 151) + avoidReferenceGrid(y + i)] = n + 1;
            i++;
        }
        /* Bottom */
        i = 0;
        x = 77 + ((layer - 1) * 2);
        y = 78 + ((layer - 1) * 2);
        for (n = start + (length * 2); n < (start + (length * 3)); n += 2) {
            AztecMap[(avoidReferenceGrid(x - i) * 151) + avoidReferenceGrid(y)] = n;
            AztecMap[(avoidReferenceGrid(x - i) * 151) + avoidReferenceGrid(y + 1)] = n + 1;
            i++;
        }
        /* Left */
        i = 0;
        x = 63 - ((layer - 1) * 2);
        y = 77 + ((layer - 1) * 2);
        for (n = start + (length * 3); n < (start + (length * 4)); n += 2) {
            AztecMap[(avoidReferenceGrid(x) * 151) + avoidReferenceGrid(y - i)] = n;
            AztecMap[(avoidReferenceGrid(x - 1) * 151) + avoidReferenceGrid(y - i)] = n + 1;
            i++;
        }
    }

    /* Central finder pattern */
    for (y = 69; y <= 81; y++) {
        for (x = 69; x <= 81; x++) {
            AztecMap[(x * 151) + y] = 1;
        }
    }
    for (y = 70; y <= 80; y++) {
        for (x = 70; x <= 80; x++) {
            AztecMap[(x * 151) + y] = 0;
        }
    }
    for (y = 71; y <= 79; y++) {
        for (x = 71; x <= 79; x++) {
            AztecMap[(x * 151) + y] = 1;
        }
    }
    for (y = 72; y <= 78; y++) {
        for (x = 72; x <= 78; x++) {
            AztecMap[(x * 151) + y] = 0;
        }
    }
    for (y = 73; y <= 77; y++) {
        for (x = 73; x <= 77; x++) {
            AztecMap[(x * 151) + y] = 1;
        }
    }
    for (y = 74; y <= 76; y++) {
        for (x = 74; x <= 76; x++) {
            AztecMap[(x * 151) + y] = 0;
        }
    }

    /* Guide bars */
    for (y = 11; y < 151; y += 16) {
        for (x = 1; x < 151; x += 2) {
            AztecMap[(x * 151) + y] = 1;
            AztecMap[(y * 151) + x] = 1;
        }
    }

    /* Descriptor */
    for (i = 0; i < 10; i++) {
        /* Top */
        AztecMap[(avoidReferenceGrid(66 + i) * 151) + avoidReferenceGrid(64)] = 20000 + i;
    }
    for (i = 0; i < 10; i++) {
        /* Right */
        AztecMap[(avoidReferenceGrid(77) * 151) + avoidReferenceGrid(66 + i)] = 20010 + i;
    }
    for (i = 0; i < 10; i++) {
        /* Bottom */
        AztecMap[(avoidReferenceGrid(75 - i) * 151) + avoidReferenceGrid(77)] = 20020 + i;
    }
    for (i = 0; i < 10; i++) {
        /* Left */
        AztecMap[(avoidReferenceGrid(64) * 151) + avoidReferenceGrid(75 - i)] = 20030 + i;
    }

    /* Orientation */
    AztecMap[(avoidReferenceGrid(64) * 151) + avoidReferenceGrid(64)] = 1;
    AztecMap[(avoidReferenceGrid(65) * 151) + avoidReferenceGrid(64)] = 1;
    AztecMap[(avoidReferenceGrid(64) * 151) + avoidReferenceGrid(65)] = 1;
    AztecMap[(avoidReferenceGrid(77) * 151) + avoidReferenceGrid(64)] = 1;
    AztecMap[(avoidReferenceGrid(77) * 151) + avoidReferenceGrid(65)] = 1;
    AztecMap[(avoidReferenceGrid(77) * 151) + avoidReferenceGrid(76)] = 1;
}

int aztec(struct zint_symbol *symbol, unsigned char source[], const size_t length) {
    int x, y, i, j, p, data_blocks, ecc_blocks, layers, total_bits;
    char binary_string[20000], bit_pattern[20045], descriptor[42];
    char adjusted_string[20000];
    unsigned char desc_data[4], desc_ecc[6];
    int err_code, ecc_level, compact, data_length, data_maxsize, codeword_size, adjusted_length;
    int remainder, padbits, count, gs1, adjustment_size;
    int debug = symbol->debug, reader = 0;
    int comp_loop = 4;

#ifdef _MSC_VER
    unsigned int* data_part;
    unsigned int* ecc_part;
#endif

    memset(binary_string, 0, 20000);
    memset(adjusted_string, 0, 20000);

    if (symbol->input_mode == GS1_MODE) {
        gs1 = 1;
    } else {
        gs1 = 0;
    }
    if (symbol->output_options & READER_INIT) {
        reader = 1;
        comp_loop = 1;
    }
    if (gs1 && reader) {
        strcpy(symbol->errtxt, "Cannot encode in GS1 and Reader Initialisation mode at the same time (E01)");
        return ZINT_ERROR_INVALID_OPTION;
    }

    populate_map();

    err_code = aztec_text_process(source, length, binary_string, gs1, symbol->eci, symbol->debug);

    if (err_code != 0) {
        strcpy(symbol->errtxt, "Input too long or too many extended ASCII characters (E02)");
        return err_code;
    }

    if (!((symbol->option_1 >= -1) && (symbol->option_1 <= 4))) {
        strcpy(symbol->errtxt, "Invalid error correction level - using default instead (E03)");
        err_code = ZINT_WARN_INVALID_OPTION;
        symbol->option_1 = -1;
    }

    ecc_level = symbol->option_1;

    if ((ecc_level == -1) || (ecc_level == 0)) {
        ecc_level = 2;
    }

    data_length = (int) strlen(binary_string);

    layers = 0; /* Keep compiler happy! */
    data_maxsize = 0; /* Keep compiler happy! */
    adjustment_size = 0;
    if (symbol->option_2 == 0) { /* The size of the symbol can be determined by Zint */
        do {
            /* Decide what size symbol to use - the smallest that fits the data */
            compact = 0; /* 1 = Aztec Compact, 0 = Normal Aztec */
            layers = 0;

            switch (ecc_level) {
                    /* For each level of error correction work out the smallest symbol which
                    the data will fit in */
                case 1: for (i = 32; i > 0; i--) {
                        if ((data_length + adjustment_size) < Aztec10DataSizes[i - 1]) {
                            layers = i;
                            compact = 0;
                            data_maxsize = Aztec10DataSizes[i - 1];
                        }
                    }
                    for (i = comp_loop; i > 0; i--) {
                        if ((data_length + adjustment_size) < AztecCompact10DataSizes[i - 1]) {
                            layers = i;
                            compact = 1;
                            data_maxsize = AztecCompact10DataSizes[i - 1];
                        }
                    }
                    break;
                case 2: for (i = 32; i > 0; i--) {
                        if ((data_length + adjustment_size) < Aztec23DataSizes[i - 1]) {
                            layers = i;
                            compact = 0;
                            data_maxsize = Aztec23DataSizes[i - 1];
                        }
                    }
                    for (i = comp_loop; i > 0; i--) {
                        if ((data_length + adjustment_size) < AztecCompact23DataSizes[i - 1]) {
                            layers = i;
                            compact = 1;
                            data_maxsize = AztecCompact23DataSizes[i - 1];
                        }
                    }
                    break;
                case 3: for (i = 32; i > 0; i--) {
                        if ((data_length + adjustment_size) < Aztec36DataSizes[i - 1]) {
                            layers = i;
                            compact = 0;
                            data_maxsize = Aztec36DataSizes[i - 1];
                        }
                    }
                    for (i = comp_loop; i > 0; i--) {
                        if ((data_length + adjustment_size) < AztecCompact36DataSizes[i - 1]) {
                            layers = i;
                            compact = 1;
                            data_maxsize = AztecCompact36DataSizes[i - 1];
                        }
                    }
                    break;
                case 4: for (i = 32; i > 0; i--) {
                        if ((data_length + adjustment_size) < Aztec50DataSizes[i - 1]) {
                            layers = i;
                            compact = 0;
                            data_maxsize = Aztec50DataSizes[i - 1];
                        }
                    }
                    for (i = comp_loop; i > 0; i--) {
                        if ((data_length + adjustment_size) < AztecCompact50DataSizes[i - 1]) {
                            layers = i;
                            compact = 1;
                            data_maxsize = AztecCompact50DataSizes[i - 1];
                        }
                    }
                    break;
            }

            if (layers == 0) { /* Couldn't find a symbol which fits the data */
                strcpy(symbol->errtxt, "Input too long (too many bits for selected ECC) (E04)");
                return ZINT_ERROR_TOO_LONG;
            }

            /* Determine codeword bitlength - Table 3 */
            codeword_size = 6; /* if (layers <= 2) */
            if ((layers >= 3) && (layers <= 8)) {
                codeword_size = 8;
            }
            if ((layers >= 9) && (layers <= 22)) {
                codeword_size = 10;
            }
            if (layers >= 23) {
                codeword_size = 12;
            }

            j = 0;
            i = 0;
            do {
                if ((j + 1) % codeword_size == 0) {
                    /* Last bit of codeword */
                    int t, done = 0;
                    count = 0;

                    /* Discover how many '1's in current codeword */
                    for (t = 0; t < (codeword_size - 1); t++) {
                        if (binary_string[(i - (codeword_size - 1)) + t] == '1') count++;
                    }

                    if (count == (codeword_size - 1)) {
                        adjusted_string[j] = '0';
                        j++;
                        done = 1;
                    }

                    if (count == 0) {
                        adjusted_string[j] = '1';
                        j++;
                        done = 1;
                    }

                    if (done == 0) {
                        adjusted_string[j] = binary_string[i];
                        j++;
                        i++;
                    }
                }
                adjusted_string[j] = binary_string[i];
                j++;
                i++;
            } while (i <= (data_length + 1));
            adjusted_string[j] = '\0';
            adjusted_length = (int) strlen(adjusted_string);
            adjustment_size = adjusted_length - data_length;

            /* Add padding */
            remainder = adjusted_length % codeword_size;

            padbits = codeword_size - remainder;
            if (padbits == codeword_size) {
                padbits = 0;
            }

            for (i = 0; i < padbits; i++) {
                strcat(adjusted_string, "1");
            }
            adjusted_length = (int) strlen(adjusted_string);

            count = 0;
            for (i = (adjusted_length - codeword_size); i < adjusted_length; i++) {
                if (adjusted_string[i] == '1') {
                    count++;
                }
            }
            if (count == codeword_size) {
                adjusted_string[adjusted_length - 1] = '0';
            }

            if (debug) {
                printf("Codewords:\n");
                for (i = 0; i < (adjusted_length / codeword_size); i++) {
                    for (j = 0; j < codeword_size; j++) {
                        printf("%c", adjusted_string[(i * codeword_size) + j]);
                    }
                    printf("\n");
                }
            }

        } while (adjusted_length > data_maxsize);
        /* This loop will only repeat on the rare occasions when the rule about not having all 1s or all 0s
        means that the binary string has had to be lengthened beyond the maximum number of bits that can
        be encoded in a symbol of the selected size */

    } else { /* The size of the symbol has been specified by the user */
        if ((reader == 1) && ((symbol->option_2 >= 2) && (symbol->option_2 <= 4))) {
            symbol->option_2 = 5;
        }
        if ((symbol->option_2 >= 1) && (symbol->option_2 <= 4)) {
            compact = 1;
            layers = symbol->option_2;
        }
        if ((symbol->option_2 >= 5) && (symbol->option_2 <= 36)) {
            compact = 0;
            layers = symbol->option_2 - 4;
        }
        if ((symbol->option_2 < 0) || (symbol->option_2 > 36)) {
            strcpy(symbol->errtxt, "Invalid Aztec Code size");
            return ZINT_ERROR_INVALID_OPTION;
        }

        /* Determine codeword bitlength - Table 3 */
        if ((layers >= 0) && (layers <= 2)) {
            codeword_size = 6;
        }
        if ((layers >= 3) && (layers <= 8)) {
            codeword_size = 8;
        }
        if ((layers >= 9) && (layers <= 22)) {
            codeword_size = 10;
        }
        if (layers >= 23) {
            codeword_size = 12;
        }

        j = 0;
        i = 0;
        do {
            if ((j + 1) % codeword_size == 0) {
                /* Last bit of codeword */
                int t, done = 0;
                count = 0;

                /* Discover how many '1's in current codeword */
                for (t = 0; t < (codeword_size - 1); t++) {
                    if (binary_string[(i - (codeword_size - 1)) + t] == '1') count++;
                }

                if (count == (codeword_size - 1)) {
                    adjusted_string[j] = '0';
                    j++;
                    done = 1;
                }

                if (count == 0) {
                    adjusted_string[j] = '1';
                    j++;
                    done = 1;
                }

                if (done == 0) {
                    adjusted_string[j] = binary_string[i];
                    j++;
                    i++;
                }
            }
            adjusted_string[j] = binary_string[i];
            j++;
            i++;
        } while (i <= (data_length + 1));
        adjusted_string[j] = '\0';
        adjusted_length = (int) strlen(adjusted_string);

        remainder = adjusted_length % codeword_size;

        padbits = codeword_size - remainder;
        if (padbits == codeword_size) {
            padbits = 0;
        }

        for (i = 0; i < padbits; i++) {
            strcat(adjusted_string, "1");
        }
        adjusted_length = (int) strlen(adjusted_string);

        count = 0;
        for (i = (adjusted_length - codeword_size); i < adjusted_length; i++) {
            if (adjusted_string[i] == '1') {
                count++;
            }
        }
        if (count == codeword_size) {
            adjusted_string[adjusted_length - 1] = '0';
        }

        /* Check if the data actually fits into the selected symbol size */
        if (compact) {
            data_maxsize = codeword_size * (AztecCompactSizes[layers - 1] - 3);
        } else {
            data_maxsize = codeword_size * (AztecSizes[layers - 1] - 3);
        }

        if (adjusted_length > data_maxsize) {
            strcpy(symbol->errtxt, "Data too long for specified Aztec Code symbol size (E05)");
            return ZINT_ERROR_TOO_LONG;
        }

        if (debug) {
            printf("Codewords:\n");
            for (i = 0; i < (adjusted_length / codeword_size); i++) {
                for (j = 0; j < codeword_size; j++) {
                    printf("%c", adjusted_string[(i * codeword_size) + j]);
                }
                printf("\n");
            }
        }

    }

    if (reader && (layers > 22)) {
        strcpy(symbol->errtxt, "Data too long for reader initialisation symbol (E06)");
        return ZINT_ERROR_TOO_LONG;
    }

    data_blocks = adjusted_length / codeword_size;

    if (compact) {
        ecc_blocks = AztecCompactSizes[layers - 1] - data_blocks;
    } else {
        ecc_blocks = AztecSizes[layers - 1] - data_blocks;
    }

    if (debug) {
        printf("Generating a ");
        if (compact) {
            printf("compact");
        } else {
            printf("full-size");
        }
        printf(" symbol with %d layers\n", layers);
        printf("Requires ");
        if (compact) {
            printf("%d", AztecCompactSizes[layers - 1]);
        } else {
            printf("%d", AztecSizes[layers - 1]);
        }
        printf(" codewords of %d-bits\n", codeword_size);
        printf("    (%d data words, %d ecc words)\n", data_blocks, ecc_blocks);
    }

#ifndef _MSC_VER
    unsigned int data_part[data_blocks + 3], ecc_part[ecc_blocks + 3];
#else
    data_part = (unsigned int*) _alloca((data_blocks + 3) * sizeof (unsigned int));
    ecc_part = (unsigned int*) _alloca((ecc_blocks + 3) * sizeof (unsigned int));
#endif
    /* Copy across data into separate integers */
    memset(data_part, 0, (data_blocks + 2) * sizeof (int));
    memset(ecc_part, 0, (ecc_blocks + 2) * sizeof (int));

    /* Split into codewords and calculate reed-colomon error correction codes */
    switch (codeword_size) {
        case 6:
            for (i = 0; i < data_blocks; i++) {
                for (p = 0; p < 6; p++) {
                    if (adjusted_string[i * codeword_size + p] == '1') {
                        data_part[i] += (0x20 >> p);
                    }
                }
            }
            rs_init_gf(0x43);
            rs_init_code(ecc_blocks, 1);
            rs_encode_long(data_blocks, data_part, ecc_part);
            for (i = (ecc_blocks - 1); i >= 0; i--) {
                for (p = 0; p < 6; p++) {
                    if (ecc_part[i] & (0x20 >> p)) {
                        strcat(adjusted_string, "1");
                    } else {
                        strcat(adjusted_string, "0");
                    }
                }
            }
            rs_free();
            break;
        case 8:
            for (i = 0; i < data_blocks; i++) {
                for (p = 0; p < 8; p++) {
                    if (adjusted_string[i * codeword_size + p] == '1') {
                        data_part[i] += (0x80 >> p);
                    }
                }
            }
            rs_init_gf(0x12d);
            rs_init_code(ecc_blocks, 1);
            rs_encode_long(data_blocks, data_part, ecc_part);
            for (i = (ecc_blocks - 1); i >= 0; i--) {
                for (p = 0; p < 8; p++) {
                    if (ecc_part[i] & (0x80 >> p)) {
                        strcat(adjusted_string, "1");
                    } else {
                        strcat(adjusted_string, "0");
                    }
                }
            }
            rs_free();
            break;
        case 10:
            for (i = 0; i < data_blocks; i++) {
                for (p = 0; p < 10; p++) {
                    if (adjusted_string[i * codeword_size + p] == '1') {
                        data_part[i] += (0x200 >> p);
                    }
                }
            }
            rs_init_gf(0x409);
            rs_init_code(ecc_blocks, 1);
            rs_encode_long(data_blocks, data_part, ecc_part);
            for (i = (ecc_blocks - 1); i >= 0; i--) {
                for (p = 0; p < 10; p++) {
                    if (ecc_part[i] & (0x200 >> p)) {
                        strcat(adjusted_string, "1");
                    } else {
                        strcat(adjusted_string, "0");
                    }
                }
            }
            rs_free();
            break;
        case 12:
            for (i = 0; i < data_blocks; i++) {
                for (p = 0; p < 12; p++) {
                    if (adjusted_string[i * codeword_size + p] == '1') {
                        data_part[i] += (0x800 >> p);
                    }
                }
            }
            rs_init_gf(0x1069);
            rs_init_code(ecc_blocks, 1);
            rs_encode_long(data_blocks, data_part, ecc_part);
            for (i = (ecc_blocks - 1); i >= 0; i--) {
                for (p = 0; p < 12; p++) {
                    if (ecc_part[i] & (0x800 >> p)) {
                        strcat(adjusted_string, "1");
                    } else {
                        strcat(adjusted_string, "0");
                    }
                }
            }
            rs_free();
            break;
    }

    /* Invert the data so that actual data is on the outside and reed-solomon on the inside */
    memset(bit_pattern, '0', 20045);

    total_bits = (data_blocks + ecc_blocks) * codeword_size;
    for (i = 0; i < total_bits; i++) {
        bit_pattern[i] = adjusted_string[total_bits - i - 1];
    }

    /* Now add the symbol descriptor */
    memset(desc_data, 0, 4);
    memset(desc_ecc, 0, 6);
    memset(descriptor, 0, 42);

    if (compact) {
        /* The first 2 bits represent the number of layers minus 1 */
        if ((layers - 1) & 0x02) {
            descriptor[0] = '1';
        } else {
            descriptor[0] = '0';
        }
        if ((layers - 1) & 0x01) {
            descriptor[1] = '1';
        } else {
            descriptor[1] = '0';
        }
        /* The next 6 bits represent the number of data blocks minus 1 */
        if (reader) {
            descriptor[2] = '1';
        } else {
            if ((data_blocks - 1) & 0x20) {
                descriptor[2] = '1';
            } else {
                descriptor[2] = '0';
            }
        }

        for (i = 3; i < 8; i++) {
            if ((data_blocks - 1) & (0x10 >> (i - 3))) {
                descriptor[i] = '1';
            } else {
                descriptor[i] = '0';
            }
        }

        descriptor[8] = '\0';
        if (debug) printf("Mode Message = %s\n", descriptor);
    } else {
        /* The first 5 bits represent the number of layers minus 1 */
        for (i = 0; i < 5; i++) {
            if ((layers - 1) & (0x10 >> i)) {
                descriptor[i] = '1';
            } else {
                descriptor[i] = '0';
            }
        }

        /* The next 11 bits represent the number of data blocks minus 1 */
        if (reader) {
            descriptor[5] = '1';
        } else {
            if ((data_blocks - 1) & 0x400) {
                descriptor[5] = '1';
            } else {
                descriptor[5] = '0';
            }
        }
        for (i = 6; i < 16; i++) {
            if ((data_blocks - 1) & (0x200 >> (i - 6))) {
                descriptor[i] = '1';
            } else {
                descriptor[i] = '0';
            }
        }
        descriptor[16] = '\0';
        if (debug) printf("Mode Message = %s\n", descriptor);
    }

    /* Split into 4-bit codewords */
    for (i = 0; i < 4; i++) {
        if (descriptor[i * 4] == '1') {
            desc_data[i] += 8;
        }
        if (descriptor[(i * 4) + 1] == '1') {
            desc_data[i] += 4;
        }
        if (descriptor[(i * 4) + 2] == '1') {
            desc_data[i] += 2;
        }
        if (descriptor[(i * 4) + 3] == '1') {
            desc_data[i] += 1;
        }
    }

    /* Add reed-solomon error correction with Galois field GF(16) and prime modulus
    x^4 + x + 1 (section 7.2.3)*/

    rs_init_gf(0x13);
    if (compact) {
        rs_init_code(5, 1);
        rs_encode(2, desc_data, desc_ecc);
        for (i = 0; i < 5; i++) {
            if (desc_ecc[4 - i] & 0x08) {
                descriptor[(i * 4) + 8] = '1';
            } else {
                descriptor[(i * 4) + 8] = '0';
            }
            if (desc_ecc[4 - i] & 0x04) {
                descriptor[(i * 4) + 9] = '1';
            } else {
                descriptor[(i * 4) + 9] = '0';
            }
            if (desc_ecc[4 - i] & 0x02) {
                descriptor[(i * 4) + 10] = '1';
            } else {
                descriptor[(i * 4) + 10] = '0';
            }
            if (desc_ecc[4 - i] & 0x01) {
                descriptor[(i * 4) + 11] = '1';
            } else {
                descriptor[(i * 4) + 11] = '0';
            }
        }
    } else {
        rs_init_code(6, 1);
        rs_encode(4, desc_data, desc_ecc);
        for (i = 0; i < 6; i++) {
            if (desc_ecc[5 - i] & 0x08) {
                descriptor[(i * 4) + 16] = '1';
            } else {
                descriptor[(i * 4) + 16] = '0';
            }
            if (desc_ecc[5 - i] & 0x04) {
                descriptor[(i * 4) + 17] = '1';
            } else {
                descriptor[(i * 4) + 17] = '0';
            }
            if (desc_ecc[5 - i] & 0x02) {
                descriptor[(i * 4) + 18] = '1';
            } else {
                descriptor[(i * 4) + 18] = '0';
            }
            if (desc_ecc[5 - i] & 0x01) {
                descriptor[(i * 4) + 19] = '1';
            } else {
                descriptor[(i * 4) + 19] = '0';
            }
        }
    }
    rs_free();

    /* Merge descriptor with the rest of the symbol */
    for (i = 0; i < 40; i++) {
        if (compact) {
            bit_pattern[2000 + i - 2] = descriptor[i];
        } else {
            bit_pattern[20000 + i - 2] = descriptor[i];
        }
    }

    /* Plot all of the data into the symbol in pre-defined spiral pattern */
    if (compact) {

        for (y = AztecCompactOffset[layers - 1]; y < (27 - AztecCompactOffset[layers - 1]); y++) {
            for (x = AztecCompactOffset[layers - 1]; x < (27 - AztecCompactOffset[layers - 1]); x++) {
                if (CompactAztecMap[(y * 27) + x] == 1) {
                    set_module(symbol, y - AztecCompactOffset[layers - 1], x - AztecCompactOffset[layers - 1]);
                }
                if (CompactAztecMap[(y * 27) + x] >= 2) {
                    if (bit_pattern[CompactAztecMap[(y * 27) + x] - 2] == '1') {
                        set_module(symbol, y - AztecCompactOffset[layers - 1], x - AztecCompactOffset[layers - 1]);
                    }
                }
            }
            symbol->row_height[y - AztecCompactOffset[layers - 1]] = 1;
        }
        symbol->rows = 27 - (2 * AztecCompactOffset[layers - 1]);
        symbol->width = 27 - (2 * AztecCompactOffset[layers - 1]);
    } else {

        for (y = AztecOffset[layers - 1]; y < (151 - AztecOffset[layers - 1]); y++) {
            for (x = AztecOffset[layers - 1]; x < (151 - AztecOffset[layers - 1]); x++) {
                if (AztecMap[(y * 151) + x] == 1) {
                    set_module(symbol, y - AztecOffset[layers - 1], x - AztecOffset[layers - 1]);
                }
                if (AztecMap[(y * 151) + x] >= 2) {
                    if (bit_pattern[AztecMap[(y * 151) + x] - 2] == '1') {
                        set_module(symbol, y - AztecOffset[layers - 1], x - AztecOffset[layers - 1]);
                    }
                }
            }
            symbol->row_height[y - AztecOffset[layers - 1]] = 1;
        }
        symbol->rows = 151 - (2 * AztecOffset[layers - 1]);
        symbol->width = 151 - (2 * AztecOffset[layers - 1]);
    }

    return err_code;
}

/* Encodes Aztec runes as specified in ISO/IEC 24778:2008 Annex A */
int aztec_runes(struct zint_symbol *symbol, unsigned char source[], int length) {
    int input_value, error_number, i, p, y, x;
    char binary_string[28];
    unsigned char data_codewords[3], ecc_codewords[6];

    error_number = 0;
    input_value = 0;
    if (length > 3) {
        strcpy(symbol->errtxt, "Input too large (E07)");
        return ZINT_ERROR_INVALID_DATA;
    }
    error_number = is_sane(NEON, source, length);
    if (error_number != 0) {
        strcpy(symbol->errtxt, "Invalid characters in input (E08)");
        return ZINT_ERROR_INVALID_DATA;
    }
    switch (length) {
        case 3: input_value = 100 * ctoi(source[0]);
            input_value += 10 * ctoi(source[1]);
            input_value += ctoi(source[2]);
            break;
        case 2: input_value = 10 * ctoi(source[0]);
            input_value += ctoi(source[1]);
            break;
        case 1: input_value = ctoi(source[0]);
            break;
    }

    if (input_value > 255) {
        strcpy(symbol->errtxt, "Input too large (E09)");
        return ZINT_ERROR_INVALID_DATA;
    }

    strcpy(binary_string, "");
    for (p = 0; p < 8; p++) {
        if (input_value & (0x80 >> p)) {
            strcat(binary_string, "1");
        } else {
            strcat(binary_string, "0");
        }
    }

    data_codewords[0] = 0;
    data_codewords[1] = 0;

    for (i = 0; i < 2; i++) {
        if (binary_string[i * 4] == '1') {
            data_codewords[i] += 8;
        }
        if (binary_string[(i * 4) + 1] == '1') {
            data_codewords[i] += 4;
        }
        if (binary_string[(i * 4) + 2] == '1') {
            data_codewords[i] += 2;
        }
        if (binary_string[(i * 4) + 3] == '1') {
            data_codewords[i] += 1;
        }
    }

    rs_init_gf(0x13);
    rs_init_code(5, 1);
    rs_encode(2, data_codewords, ecc_codewords);
    rs_free();

    strcpy(binary_string, "");

    for (i = 0; i < 5; i++) {
        if (ecc_codewords[4 - i] & 0x08) {
            binary_string[(i * 4) + 8] = '1';
        } else {
            binary_string[(i * 4) + 8] = '0';
        }
        if (ecc_codewords[4 - i] & 0x04) {
            binary_string[(i * 4) + 9] = '1';
        } else {
            binary_string[(i * 4) + 9] = '0';
        }
        if (ecc_codewords[4 - i] & 0x02) {
            binary_string[(i * 4) + 10] = '1';
        } else {
            binary_string[(i * 4) + 10] = '0';
        }
        if (ecc_codewords[4 - i] & 0x01) {
            binary_string[(i * 4) + 11] = '1';
        } else {
            binary_string[(i * 4) + 11] = '0';
        }
    }

    for (i = 0; i < 28; i += 2) {
        if (binary_string[i] == '1') {
            binary_string[i] = '0';
        } else {
            binary_string[i] = '1';
        }
    }

    for (y = 8; y < 19; y++) {
        for (x = 8; x < 19; x++) {
            if (CompactAztecMap[(y * 27) + x] == 1) {
                set_module(symbol, y - 8, x - 8);
            }
            if (CompactAztecMap[(y * 27) + x] >= 2) {
                if (binary_string[CompactAztecMap[(y * 27) + x] - 2000] == '1') {
                    set_module(symbol, y - 8, x - 8);
                }
            }
        }
        symbol->row_height[y - 8] = 1;
    }
    symbol->rows = 11;
    symbol->width = 11;

    return 0;
}