--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/zint/backend/code16k.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,599 @@
+/* code16k.c - Handles Code 16k stacked symbology */
+/*
+    libzint - the open source barcode library
+    Copyright (C) 2008-2024 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.
+ */
+/* SPDX-License-Identifier: BSD-3-Clause */
+
+/* Updated to comply with BS EN 12323:2005 */
+
+/* Code 16k can hold up to 77 characters or 154 numbers */
+
+#include <assert.h>
+#include <stdio.h>
+#include "common.h"
+#include "code128.h"
+
+/* Note these previously defined in "code128.h" with `C128_` prefix */
+#define C16K_LATCHA 'A'
+#define C16K_LATCHB 'B'
+#define C16K_LATCHC 'C'
+#define C16K_SHIFTA 'a'
+#define C16K_SHIFTB 'b'
+#define C16K_ABORC  '9'
+#define C16K_AORB   'Z'
+
+/* Note using C128Table with extra entry at 106 (Triple Shift) for C16KTable */
+
+/* EN 12323 Table 3 and Table 4 - Start patterns and stop patterns */
+static const char C16KStartStop[8][4] = {
+    {'3','2','1','1'}, {'2','2','2','1'}, {'2','1','2','2'}, {'1','4','1','1'},
+    {'1','1','3','2'}, {'1','2','3','1'}, {'1','1','1','4'}, {'3','1','1','2'}
+};
+
+/* EN 12323 Table 5 - Start and stop values defining row numbers */
+static const unsigned char C16KStartValues[16] = {
+    0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7
+};
+
+static const unsigned char C16KStopValues[16] = {
+    0, 1, 2, 3, 4, 5, 6, 7, 4, 5, 6, 7, 0, 1, 2, 3
+};
+
+/* Determine appropriate mode for a given character (was `c128_parunmodd()`) */
+static int c16k_parunmodd(const unsigned char llyth, const int check_fnc1) {
+    int modd;
+
+    if (llyth <= 31) {
+        modd = check_fnc1 && llyth == '\x1D' ? C16K_ABORC : C16K_SHIFTA;
+    } else if ((llyth >= 48) && (llyth <= 57)) {
+        modd = C16K_ABORC;
+    } else if (llyth <= 95) {
+        modd = C16K_AORB;
+    } else if (llyth <= 127) {
+        modd = C16K_SHIFTB;
+    } else if (llyth <= 159) {
+        modd = C16K_SHIFTA;
+    } else if (llyth <= 223) {
+        modd = C16K_AORB;
+    } else {
+        modd = C16K_SHIFTB;
+    }
+
+    return modd;
+}
+
+/* Bring together same type blocks (was `c128_grwp()`) */
+static void c16k_grwp(int list[2][C128_MAX], int *p_indexliste) {
+
+    if (*p_indexliste > 1) {
+        int i = 1;
+        while (i < *p_indexliste) {
+            if (list[1][i - 1] == list[1][i]) {
+                int j;
+                /* Bring together */
+                list[0][i - 1] = list[0][i - 1] + list[0][i];
+                j = i + 1;
+
+                /* Decrease the list */
+                while (j < *p_indexliste) {
+                    list[0][j - 1] = list[0][j];
+                    list[1][j - 1] = list[1][j];
+                    j++;
+                }
+                *p_indexliste = *p_indexliste - 1;
+                i--;
+            }
+            i++;
+        }
+    }
+}
+
+/* Implements rules from ISO/IEC 15417:2007 Annex E (was `c128_dxsmooth()`) */
+static void c16k_dxsmooth(int list[2][C128_MAX], int *p_indexliste) {
+    int i, j, nextshift = 0 /*Suppresses gcc -Wmaybe-uninitialized false positive*/, nextshift_i = 0;
+    const int indexliste = *p_indexliste;
+
+    for (i = 0; i < indexliste; i++) {
+        int current = list[1][i]; /* Either C16K_ABORC, C16K_AORB, C16K_SHIFTA or C16K_SHIFTB */
+        int length = list[0][i];
+        if (i == nextshift_i) {
+            nextshift = 0;
+            /* Set next shift to aid deciding between latching to A or B - taken from Okapi, props Daniel Gredler */
+            for (j = i + 1; j < indexliste; j++) {
+                if (list[1][j] == C16K_SHIFTA || list[1][j] == C16K_SHIFTB) {
+                    nextshift = list[1][j];
+                    nextshift_i = j;
+                    break;
+                }
+            }
+        }
+
+        if (i == 0) { /* first block */
+            if (current == C16K_ABORC) {
+                if ((indexliste == 1) && (length == 2)) {
+                    /* Rule 1a */
+                    list[1][i] = C16K_LATCHC;
+                    current = C16K_LATCHC;
+                } else if (length >= 4) {
+                    /* Rule 1b */
+                    list[1][i] = C16K_LATCHC;
+                    current = C16K_LATCHC;
+                } else {
+                    current = C16K_AORB; /* Determine below */
+                }
+            }
+            if (current == C16K_AORB) {
+                if (nextshift == C16K_SHIFTA) {
+                    /* Rule 1c */
+                    list[1][i] = C16K_LATCHA;
+                } else {
+                    /* Rule 1d */
+                    list[1][i] = C16K_LATCHB;
+                }
+            } else if (current == C16K_SHIFTA) {
+                /* Rule 1c */
+                list[1][i] = C16K_LATCHA;
+            } else if (current == C16K_SHIFTB) { /* Unless C16K_LATCHX set above, can only be C16K_SHIFTB */
+                /* Rule 1d */
+                list[1][i] = C16K_LATCHB;
+            }
+        } else {
+            int last = list[1][i - 1];
+            if (current == C16K_ABORC) {
+                if (length >= 4) {
+                    /* Rule 3 - note Rule 3b (odd C blocks) dealt with later */
+                    list[1][i] = C16K_LATCHC;
+                    current = C16K_LATCHC;
+                } else {
+                    current = C16K_AORB; /* Determine below */
+                }
+            }
+            if (current == C16K_AORB) {
+                if (last == C16K_LATCHA || last == C16K_SHIFTB) { /* Maintain state */
+                    list[1][i] = C16K_LATCHA;
+                } else if (last == C16K_LATCHB || last == C16K_SHIFTA) { /* Maintain state */
+                    list[1][i] = C16K_LATCHB;
+                } else if (nextshift == C16K_SHIFTA) {
+                    list[1][i] = C16K_LATCHA;
+                } else {
+                    list[1][i] = C16K_LATCHB;
+                }
+            } else if (current == C16K_SHIFTA) {
+                if (length > 1) {
+                    /* Rule 4 */
+                    list[1][i] = C16K_LATCHA;
+                } else if (last == C16K_LATCHA || last == C16K_SHIFTB) { /* Maintain state */
+                    list[1][i] = C16K_LATCHA;
+                } else if (last == C16K_LATCHC) {
+                    list[1][i] = C16K_LATCHA;
+                }
+            } else if (current == C16K_SHIFTB) { /* Unless C16K_LATCHX set above, can only be C16K_SHIFTB */
+                if (length > 1) {
+                    /* Rule 5 */
+                    list[1][i] = C16K_LATCHB;
+                } else if (last == C16K_LATCHB || last == C16K_SHIFTA) { /* Maintain state */
+                    list[1][i] = C16K_LATCHB;
+                } else if (last == C16K_LATCHC) {
+                    list[1][i] = C16K_LATCHB;
+                }
+            }
+        } /* Rule 2 is implemented elsewhere, Rule 6 is implied */
+    }
+
+    c16k_grwp(list, p_indexliste);
+}
+
+/* Put set data into set[]. Resolves odd C blocks (was  `c128_put_in_set()`) */
+static void c16k_put_in_set(int list[2][C128_MAX], const int indexliste, char set[C128_MAX],
+                const unsigned char *source) {
+    int read = 0;
+    int i, j;
+    int c_count = 0, have_nonc = 0;
+
+    for (i = 0; i < indexliste; i++) {
+        for (j = 0; j < list[0][i]; j++) {
+            set[read++] = list[1][i];
+        }
+    }
+    /* Watch out for odd-length Mode C blocks */
+    for (i = 0; i < read; i++) {
+        if (set[i] == 'C') {
+            if (source[i] == '\x1D') {
+                if (c_count & 1) {
+                    have_nonc = 1;
+                    if (i > c_count) {
+                        set[i - c_count] = 'B';
+                    } else {
+                        set[i - 1] = 'B';
+                    }
+                }
+                c_count = 0;
+            } else {
+                c_count++;
+            }
+        } else {
+            have_nonc = 1;
+            if (c_count & 1) {
+                if (i > c_count) {
+                    set[i - c_count] = 'B';
+                } else {
+                    set[i - 1] = 'B';
+                }
+            }
+            c_count = 0;
+        }
+    }
+    if (c_count & 1) {
+        if (i > c_count && have_nonc) {
+            set[i - c_count] = 'B';
+            if (c_count < 4) {
+                /* Rule 1b */
+                for (j = i - c_count + 1; j < i; j++) {
+                    set[j] = 'B';
+                }
+            }
+        } else {
+            set[i - 1] = 'B';
+        }
+    }
+    for (i = 1; i < read - 1; i++) {
+        if (set[i] == 'C' && set[i - 1] != 'C' && set[i + 1] != 'C') {
+            set[i] = set[i + 1];
+        }
+    }
+    if (read > 1 && set[read - 1] == 'C' && set[read - 2] != 'C') {
+        set[read - 1] = set[read - 2];
+    }
+}
+
+/**
+ * Translate Code 128 Set A characters into barcodes (was `c128_set_a()`).
+ * This set handles all control characters NUL to US
+ */
+static void c16k_set_a(const unsigned char source, int values[], int *bar_chars) {
+
+    if (source >= 128) {
+        if (source < 160) {
+            values[(*bar_chars)] = (source - 128) + 64;
+        } else {
+            values[(*bar_chars)] = (source - 128) - 32;
+        }
+    } else {
+        if (source < 32) {
+            values[(*bar_chars)] = source + 64;
+        } else {
+            values[(*bar_chars)] = source - 32;
+        }
+    }
+    (*bar_chars)++;
+}
+
+/**
+ * Translate Code 128 Set B characters into barcodes (was `c128_set_b()`).
+ * This set handles all characters which are not part of long numbers and not
+ * control characters
+ */
+static int c16k_set_b(const unsigned char source, int values[], int *bar_chars) {
+    if (source >= 128 + 32) {
+        values[(*bar_chars)] = source - 32 - 128;
+    } else if (source >= 128) { /* Should never happen */
+        return 0; /* Not reached */
+    } else if (source >= 32) {
+        values[(*bar_chars)] = source - 32;
+    } else { /* Should never happen */
+        return 0; /* Not reached */
+    }
+    (*bar_chars)++;
+    return 1;
+}
+
+/* Translate Code 128 Set C characters into barcodes (was `c128_set_c()`).
+ * This set handles numbers in a compressed form
+ */
+static void c16k_set_c(const unsigned char source_a, const unsigned char source_b, int values[], int *bar_chars) {
+    values[(*bar_chars)] = 10 * (source_a - '0') + source_b - '0';
+    (*bar_chars)++;
+}
+
+/* Code 16k EN 12323:2005 */
+INTERNAL int code16k(struct zint_symbol *symbol, unsigned char source[], int length) {
+    char width_pattern[40]; /* 4 (start) + 1 (guard) + 5*6 (chars) + 4 (stop) + 1 */
+    int current_row, rows, looper, first_check, second_check;
+    int indexchaine;
+    int list[2][C128_MAX] = {{0}};
+    char set[C128_MAX] = {0}, fset[C128_MAX] = {0}, mode, current_set;
+    int pads_needed, indexliste, i, m, read, mx_reader;
+    int extra_pads = 0;
+    int values[C128_MAX] = {0};
+    int bar_characters;
+    int error_number = 0, first_sum, second_sum;
+    const int gs1 = (symbol->input_mode & 0x07) == GS1_MODE;
+    const int debug_print = symbol->debug & ZINT_DEBUG_PRINT;
+
+    if (length > C128_MAX) {
+        return errtxtf(ZINT_ERROR_TOO_LONG, symbol, 420, "Input length %d too long (maximum " C128_MAX_S ")", length);
+    }
+
+    if (symbol->option_1 == 1 || symbol->option_1 > 16) {
+        return errtxtf(ZINT_ERROR_INVALID_OPTION, symbol, 424, "Minimum number of rows '%d' out of range (2 to 16)",
+                        symbol->option_1);
+    }
+
+    /* Detect extended ASCII characters */
+    for (i = 0; i < length; i++) {
+        fset[i] = source[i] >= 128 ? 'f' : ' ';
+    }
+    /* Note to be safe not using extended ASCII latch as not mentioned in BS EN 12323:2005 */
+
+    /* Detect mode A, B and C characters */
+    indexliste = 0;
+    indexchaine = 0;
+
+    mode = c16k_parunmodd(source[indexchaine], gs1 /*check_fnc1*/);
+
+    do {
+        list[1][indexliste] = mode;
+        while ((list[1][indexliste] == mode) && (indexchaine < length)) {
+            list[0][indexliste]++;
+            indexchaine++;
+            if (indexchaine == length) {
+                break;
+            }
+            mode = c16k_parunmodd(source[indexchaine], gs1 /*check_fnc1*/);
+        }
+        indexliste++;
+    } while (indexchaine < length);
+
+    c16k_dxsmooth(list, &indexliste);
+
+    /* Put set data into set[], resolving odd C blocks */
+    c16k_put_in_set(list, indexliste, set, source);
+
+    if (debug_print) {
+        printf("Data: %.*s\n", length, source);
+        printf(" Set: %.*s\n", length, set);
+        printf("FSet: %.*s\n", length, fset);
+    }
+
+    /* start with the mode character - Table 2 */
+    m = 0;
+    switch (set[0]) {
+        case 'A': m = 0;
+            break;
+        case 'B': m = 1;
+            break;
+        case 'C': m = 2;
+            break;
+    }
+
+    if (symbol->output_options & READER_INIT) {
+        if (gs1) {
+            return errtxt(ZINT_ERROR_INVALID_OPTION, symbol, 422, "Cannot use Reader Initialisation in GS1 mode");
+        }
+        if (m == 2) {
+            m = 5;
+        } else if ((set[0] == 'B') && (set[1] == 'C') && fset[0] != 'f') {
+            m = 6;
+        }
+        values[1] = 96; /* FNC3 */
+        bar_characters = 2;
+    } else {
+        if (gs1) {
+            /* Integrate FNC1 */
+            switch (set[0]) {
+                case 'B': m = 3;
+                    break;
+                case 'C': m = 4;
+                    break;
+            }
+        } else {
+            if ((set[0] == 'B') && (set[1] == 'C')) {
+                m = fset[0] == 'f' ? 6 : 5;
+            } else if ((set[0] == 'B') && (set[1] == 'B') && (set[2] == 'C') && fset[0] != 'f' && fset[1] != 'f') {
+                m = 6;
+            }
+        }
+        bar_characters = 1;
+    }
+
+    current_set = set[0];
+    read = 0;
+
+    /* Encode the data */
+    /* TODO: make use of extra (non-CODE128) shifts: 1SB, 2SA/B/C, 3SB/C */
+    do {
+
+        if ((read != 0) && (set[read] != current_set)) {
+            /* Latch different code set */
+            switch (set[read]) {
+                case 'A':
+                    values[bar_characters++] = 101;
+                    current_set = 'A';
+                    break;
+                case 'B':
+                    values[bar_characters++] = 100;
+                    current_set = 'B';
+                    break;
+                case 'C':
+                    /* If not Mode C/Shift B and not Mode C/Double Shift B */
+                    if (!(read == 1 && m >= 5) && !(read == 2 && m == 6)) {
+                        values[bar_characters++] = 99;
+                    }
+                    current_set = 'C';
+                    break;
+            }
+        }
+
+        if (fset[read] == 'f') {
+            /* Shift extended mode */
+            switch (current_set) {
+                case 'A':
+                    values[bar_characters++] = 101; /* FNC 4 */
+                    break;
+                case 'B':
+                    values[bar_characters++] = 100; /* FNC 4 */
+                    break;
+            }
+        }
+
+        if ((set[read] == 'a') || (set[read] == 'b')) {
+            /* Insert shift character */
+            values[bar_characters++] = 98;
+        }
+
+        if (!gs1 || source[read] != '\x1D') {
+            switch (set[read]) { /* Encode data characters */
+                case 'A':
+                case 'a': c16k_set_a(source[read], values, &bar_characters);
+                    read++;
+                    break;
+                case 'B':
+                case 'b': (void) c16k_set_b(source[read], values, &bar_characters);
+                    read++;
+                    break;
+                case 'C': c16k_set_c(source[read], source[read + 1], values, &bar_characters);
+                    read += 2;
+                    break;
+            }
+        } else {
+            values[bar_characters++] = 102;
+            read++;
+        }
+
+        if (bar_characters > 80 - 2) { /* Max rows 16 * 5 - 2 check chars */
+            return errtxtf(ZINT_ERROR_TOO_LONG, symbol, 421,
+                            "Input too long, requires %d symbol characters (maximum 78)", bar_characters);
+        }
+    } while (read < length);
+
+    pads_needed = 5 - ((bar_characters + 2) % 5);
+    if (pads_needed == 5) {
+        pads_needed = 0;
+    }
+    if ((bar_characters + pads_needed) < 8) {
+        pads_needed += 8 - (bar_characters + pads_needed);
+    }
+
+    rows = (bar_characters + pads_needed + 4) / 5;
+    if (symbol->option_1 > rows) {
+        extra_pads = (symbol->option_1 - rows) * 5;
+        rows = symbol->option_1;
+    }
+
+    for (i = 0; i < pads_needed + extra_pads; i++) {
+        values[bar_characters++] = 103;
+    }
+    values[0] = (7 * (rows - 2)) + m; /* see 4.3.4.2 */
+
+    /* Calculate check digits */
+    first_sum = 0;
+    second_sum = 0;
+    for (i = 0; i < bar_characters; i++) {
+        first_sum += (i + 2) * values[i];
+        second_sum += (i + 1) * values[i];
+    }
+    first_check = first_sum % 107;
+    second_sum += first_check * (bar_characters + 1);
+    second_check = second_sum % 107;
+    values[bar_characters] = first_check;
+    values[bar_characters + 1] = second_check;
+    bar_characters += 2;
+
+    if (debug_print) {
+        printf("Codewords (%d):", bar_characters);
+        for (i = 0; i < bar_characters; i++) {
+            if (i % 5 == 0) {
+                fputc('\n', stdout);
+            }
+            printf(" %3d", values[i]);
+        }
+        fputc('\n', stdout);
+    }
+#ifdef ZINT_TEST
+    if (symbol->debug & ZINT_DEBUG_TEST) {
+        debug_test_codeword_dump_int(symbol, values, bar_characters); /* Missing row start/stop */
+    }
+#endif
+
+    assert(rows * 5 == bar_characters);
+
+    for (current_row = 0; current_row < rows; current_row++) {
+        int writer;
+        int flip_flop;
+        int len;
+        char *d = width_pattern;
+
+        memcpy(d, C16KStartStop[C16KStartValues[current_row]], 4);
+        d += 4;
+        *d++ = '1';
+        for (i = 0; i < 5; i++, d += 6) {
+            memcpy(d, C128Table[values[(current_row * 5) + i]], 6);
+        }
+        memcpy(d, C16KStartStop[C16KStopValues[current_row]], 4);
+        d += 4;
+
+        /* Write the information into the symbol */
+        writer = 0;
+        flip_flop = 1;
+        for (mx_reader = 0, len = d - width_pattern; mx_reader < len; mx_reader++) {
+            for (looper = 0; looper < ctoi(width_pattern[mx_reader]); looper++) {
+                if (flip_flop == 1) {
+                    set_module(symbol, current_row, writer);
+                }
+                writer++;
+            }
+            flip_flop = !flip_flop;
+        }
+    }
+
+    symbol->rows = rows;
+    symbol->width = 70;
+
+    if (symbol->output_options & COMPLIANT_HEIGHT) {
+        /* BS EN 12323:2005 Section 4.5 (d) minimum 8X; use 10X as default
+           Section 4.5 (b) H = X[r(h + g) + g] = rows * row_height + (rows - 1) * separator as borders not included
+           in symbol->height (added on) */
+        const int separator = symbol->option_3 >= 1 && symbol->option_3 <= 4 ? symbol->option_3 : 1;
+        const float min_row_height = stripf((8.0f * rows + separator * (rows - 1)) / rows);
+        const float default_height = 10.0f * rows + separator * (rows - 1);
+        error_number = set_height(symbol, min_row_height, default_height, 0.0f, 0 /*no_errtxt*/);
+    } else {
+        (void) set_height(symbol, 0.0f, 10.0f * rows, 0.0f, 1 /*no_errtxt*/);
+    }
+
+    symbol->output_options |= BARCODE_BIND;
+
+    if (symbol->border_width == 0) { /* Allow override if non-zero */
+        symbol->border_width = 1; /* BS EN 12323:2005 Section 4.3.7 minimum (note change from previous default 2) */
+    }
+
+    return error_number;
+}
+
+/* vim: set ts=4 sw=4 et : */