--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/zint/backend/general_field.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,208 @@
+/* general_field.c - Handles general field compaction (GS1 DataBar and composites) */
+/*
+    libzint - the open source barcode library
+    Copyright (C) 2019-2024 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 */
+
+#include "common.h"
+#include "general_field.h"
+
+static const char alphanum_puncs[] = "*,-./";
+static const char isoiec_puncs[] = "!\"%&'()*+,-./:;<=>?_ "; /* Note contains space, not in cset82 */
+#define IS_ISOIEC_F (IS_LWR_F | IS_C82_F | IS_AST_F | IS_PLS_F | IS_MNS_F | IS_SPC_F)
+
+/* Returns type of char at `i`. FNC1 counted as NUMERIC. Returns 0 if invalid char */
+static int general_field_type(const char *general_field, const int i) {
+    if (general_field[i] == '\x1D' || z_isdigit(general_field[i])) {
+        return NUMERIC;
+    }
+    if (z_isupper(general_field[i]) || posn(alphanum_puncs, general_field[i]) != -1) {
+        return ALPHANUMERIC;
+    }
+    if (!not_sane(IS_ISOIEC_F, (const unsigned char *) general_field + i, 1)) {
+        return ISOIEC;
+    }
+    return 0;
+}
+
+/* Returns true if next (including `i`) `num` chars of type `type`, or if given (non-zero), `type2` */
+static int general_field_next(const char *general_field, int i, const int general_field_len, int num, const int type,
+            const int type2) {
+    if (i + num > general_field_len) {
+        return 0;
+    }
+    for (; i < general_field_len && num; i++, num--) {
+        int type_i = general_field_type(general_field, i);
+        if ((type_i != type && !type2) || (type_i != type && type_i != type2)) {
+            return 0;
+        }
+    }
+    return num == 0;
+}
+
+/* Returns true if next (including `i`) `num` up to `max_num` chars of type `type` and occur at end */
+static int general_field_next_terminate(const char *general_field, int i, const int general_field_len, int num,
+            const int max_num, const int type) {
+    if (i + max_num < general_field_len) {
+        return 0;
+    }
+    for (; i < general_field_len; i++, num--) {
+        if (general_field_type(general_field, i) != type) {
+            return 0;
+        }
+    }
+    return i == general_field_len && num <= 0;
+}
+
+/* Returns true if none of the next (including `i`) `num` chars (or end occurs) of type `type` */
+static int general_field_next_none(const char *general_field, int i, const int general_field_len, int num,
+            const int type) {
+    for (; i < general_field_len && num; i++, num--) {
+        if (general_field_type(general_field, i) == type) {
+            return 0;
+        }
+    }
+    return num == 0 || i == general_field_len;
+}
+
+/* Attempts to apply encoding rules from sections 7.2.5.5.1 to 7.2.5.5.3
+ * of ISO/IEC 24724:2011 (same as sections 5.4.1 to 5.4.3 of ISO/IEC 24723:2010) */
+INTERNAL int general_field_encode(const char *general_field, const int general_field_len, int *p_mode,
+                char *p_last_digit, char binary_string[], int *p_bp) {
+    int i, d1, d2;
+    int mode = *p_mode;
+    char last_digit = '\0'; /* Set to odd remaining digit at end if any */
+    int bp = *p_bp;
+
+    for (i = 0; i < general_field_len; ) {
+        int type = general_field_type(general_field, i);
+        if (!type) {
+            return 0;
+        }
+        switch (mode) {
+            case NUMERIC:
+                if (i < general_field_len - 1) { /* If at least 2 characters remain */
+                    if (type != NUMERIC || general_field_type(general_field, i + 1) != NUMERIC) {
+                        /* 7.2.5.5.1/5.4.1 a) */
+                        bp = bin_append_posn(0, 4, binary_string, bp); /* Alphanumeric latch "0000" */
+                        mode = ALPHANUMERIC;
+                    } else {
+                        d1 = general_field[i] == '\x1D' ? 10 : ctoi(general_field[i]);
+                        d2 = general_field[i + 1] == '\x1D' ? 10 : ctoi(general_field[i + 1]);
+                        bp = bin_append_posn((11 * d1) + d2 + 8, 7, binary_string, bp);
+                        i += 2;
+                    }
+                } else { /* If 1 character remains */
+                    if (type != NUMERIC) {
+                        /* 7.2.5.5.1/5.4.1 b) */
+                        bp = bin_append_posn(0, 4, binary_string, bp); /* Alphanumeric latch "0000" */
+                        mode = ALPHANUMERIC;
+                    } else {
+                        /* Ending with single digit.
+                         * 7.2.5.5.1 c) and 5.4.1 c) dealt with separately outside this procedure */
+                        last_digit = general_field[i];
+                        i++;
+                    }
+                }
+                break;
+            case ALPHANUMERIC:
+                if (general_field[i] == '\x1D') {
+                    /* 7.2.5.5.2/5.4.2 a) */
+                    bp = bin_append_posn(15, 5, binary_string, bp); /* "01111" */
+                    mode = NUMERIC;
+                    i++;
+                } else if (type == ISOIEC) {
+                    /* 7.2.5.5.2/5.4.2 b) */
+                    bp = bin_append_posn(4, 5, binary_string, bp); /* ISO/IEC 646 latch "00100" */
+                    mode = ISOIEC;
+                } else if (general_field_next(general_field, i, general_field_len, 6, NUMERIC, 0)) {
+                    /* 7.2.5.5.2/5.4.2 c) */
+                    bp = bin_append_posn(0, 3, binary_string, bp); /* Numeric latch "000" */
+                    mode = NUMERIC;
+                } else if (general_field_next_terminate(general_field, i, general_field_len, 4,
+                            5 /*Can limit to 5 max due to above*/, NUMERIC)) {
+                    /* 7.2.5.5.2/5.4.2 d) */
+                    bp = bin_append_posn(0, 3, binary_string, bp); /* Numeric latch "000" */
+                    mode = NUMERIC;
+                } else if (z_isdigit(general_field[i])) {
+                    bp = bin_append_posn(general_field[i] - 43, 5, binary_string, bp);
+                    i++;
+                } else if (z_isupper(general_field[i])) {
+                    bp = bin_append_posn(general_field[i] - 33, 6, binary_string, bp);
+                    i++;
+                } else {
+                    bp = bin_append_posn(posn(alphanum_puncs, general_field[i]) + 58, 6, binary_string, bp);
+                    i++;
+                }
+                break;
+            case ISOIEC:
+                if (general_field[i] == '\x1D') {
+                    /* 7.2.5.5.3/5.4.3 a) */
+                    bp = bin_append_posn(15, 5, binary_string, bp); /* "01111" */
+                    mode = NUMERIC;
+                    i++;
+                } else {
+                    int next_10_not_isoiec = general_field_next_none(general_field, i, general_field_len, 10, ISOIEC);
+                    if (next_10_not_isoiec && general_field_next(general_field, i, general_field_len, 4,
+                                                NUMERIC, 0)) {
+                        /* 7.2.5.5.3/5.4.3 b) */
+                        bp = bin_append_posn(0, 3, binary_string, bp); /* Numeric latch "000" */
+                        mode = NUMERIC;
+                    } else if (next_10_not_isoiec && general_field_next(general_field, i, general_field_len, 5,
+                                                        ALPHANUMERIC, NUMERIC)) {
+                        /* 7.2.5.5.3/5.4.3 c) */
+                        /* Note this rule can produce longer bitstreams if most of the alphanumerics are numeric */
+                        bp = bin_append_posn(4, 5, binary_string, bp); /* Alphanumeric latch "00100" */
+                        mode = ALPHANUMERIC;
+                    } else if (z_isdigit(general_field[i])) {
+                        bp = bin_append_posn(general_field[i] - 43, 5, binary_string, bp);
+                        i++;
+                    } else if (z_isupper(general_field[i])) {
+                        bp = bin_append_posn(general_field[i] - 1, 7, binary_string, bp);
+                        i++;
+                    } else if (z_islower(general_field[i])) {
+                        bp = bin_append_posn(general_field[i] - 7, 7, binary_string, bp);
+                        i++;
+                    } else {
+                        bp = bin_append_posn(posn(isoiec_puncs, general_field[i]) + 232, 8, binary_string, bp);
+                        i++;
+                    }
+                }
+                break;
+        }
+    }
+
+    *p_mode = mode;
+    *p_last_digit = last_digit;
+    *p_bp = bp;
+
+    return 1;
+}
+
+/* vim: set ts=4 sw=4 et : */