QRCODE: implement pre-calculated QR/MICROQR masks ala BWIPP for a

slight performance gain (2-3%), see https://sourceforge.net/p/zint/mailman/message/59278637/ - generated by "backend/tools/gen_qr_masks.php" test suite: update BWIPP to latest
2026-01-11 22:16:02 +00:00 · 2026-01-06 11:50:06 +00:00
parent 973594a624
commit 64aa8e654c
5 changed files with 138 additions and 62 deletions
--- a/backend/channel.c
+++ b/backend/channel.c
@@ -1,7 +1,7 @@
 /* channel.c - Handles Channel */
 /*
    libzint - the open source barcode library
-    Copyright (C) 2008-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2008-2026 Robin Stuart <rstuart114@gmail.com>

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
@@ -87,7 +87,8 @@ static int channel_copy_precalc(channel_precalc *const precalc, int B[8], int S[
   assume no liability for the use of this document." */
 static void CHNCHR(int channels, int target_value, int B[8], int S[8]) {
    /* Use of initial pre-calculations taken from Barcode Writer in Pure PostScript (BWIPP)
-     * Copyright (c) 2004-2020 Terry Burton (MIT/X-Consortium license) */
+       Copyright (c) 2004-2026 Terry Burton */
+    /* SPDX-License-Identifier: MIT */
    static channel_precalc initial_precalcs[6] = {
        { 0, { 1, 1, 1, 1, 1, 2, 1, 2, }, { 1, 1, 1, 1, 1, 1, 1, 3, }, { 1, 1, 1, 1, 1, 3, 2, },
            { 1, 1, 1, 1, 1, 3, 3, }, },
--- a/backend/qr.c
+++ b/backend/qr.c
@@ -1,7 +1,7 @@
 /*  qr.c Handles QR Code, Micro QR Code, UPNQR and rMQR */
 /*
    libzint - the open source barcode library
-    Copyright (C) 2009-2025 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2009-2026 Robin Stuart <rstuart114@gmail.com>

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
@@ -1003,7 +1003,7 @@ static void qr_populate_grid(unsigned char *grid, const int h_size, const int v_
    i = 0;
    while (i < n) {
        int x = x_start - (row * 2);
-        int r = y * h_size;
+        const int r = y * h_size;

        if (x < 6 && not_rmqr)
            x--; /* skip over vertical timing pattern */
@@ -1308,11 +1308,11 @@ static void qr_add_format_info(unsigned char *grid, const int size, const int ec
 static int qr_apply_bitmask(unsigned char *grid, const int size, const int ecc_level, const int user_mask,
            const int fast_encode, const int debug_print) {
    int x, y;
-    int r, k;
+    int k;
    int bit;
    int pattern, penalty[8];
    int best_pattern;
-    int size_squared = size * size;
+    const int size_squared = size * size;
    unsigned char *mask = (unsigned char *) z_alloca(size_squared);
    unsigned char *local = (unsigned char *) z_alloca(size_squared);
 #ifdef ZINTLOG
@@ -1322,41 +1322,13 @@ static int qr_apply_bitmask(unsigned char *grid, const int size, const int ecc_l
    /* Perform data masking */
    memset(mask, 0, size_squared);
    for (y = 0; y < size; y++) {
-        r = y * size;
+        const int ymod = y % 12;
+        const int r = y * size;
        for (x = 0; x < size; x++) {

-            /* all eight bitmask variants are encoded in the 8 bits of the bytes that make up the mask array. */
-            if (!(grid[r + x] & 0xF0)) { /* exclude areas not to be masked. */
-                if (((y + x) & 1) == 0) {
-                    mask[r + x] |= 0x01;
-                }
-                if (!fast_encode) {
-                    if ((y & 1) == 0) {
-                        mask[r + x] |= 0x02;
-                    }
-                }
-                if (x % 3 == 0) {
-                    mask[r + x] |= 0x04;
-                }
-                if (!fast_encode) {
-                    if ((y + x) % 3 == 0) {
-                        mask[r + x] |= 0x08;
-                    }
-                }
-                if (((y / 2 + x / 3) & 1) == 0) {
-                    mask[r + x] |= 0x10;
-                }
-                if (!fast_encode) {
-                    if ((y * x) % 6 == 0) { /* Equivalent to (y * x) % 2 + (y * x) % 3 == 0 */
-                        mask[r + x] |= 0x20;
-                    }
-                    if (((((y * x) & 1) + (y * x) % 3) & 1) == 0) {
-                        mask[r + x] |= 0x40;
-                    }
-                }
-                if (((((y + x) & 1) + (y * x) % 3) & 1) == 0) {
-                    mask[r + x] |= 0x80;
-                }
+            /* All eight bitmask variants are encoded in the 8 bits of the bytes that make up the mask array. */
+            if (!(grid[r + x] & 0xF0)) { /* Exclude areas not to be masked. */
+                mask[r + x] = qr_masks[ymod][x % 6]; /* Pre-calculated table ala BWIPP, see "qr.h" */
            }
        }
    }
@@ -1364,7 +1336,7 @@ static int qr_apply_bitmask(unsigned char *grid, const int size, const int ecc_l
    if (user_mask) {
        best_pattern = user_mask - 1;
    } else {
-        /* all eight bitmask variants have been encoded in the 8 bits of the bytes
+        /* All eight bitmask variants have been encoded in the 8 bits of the bytes
         * that make up the mask array. select them for evaluation according to the
         * desired pattern.*/
        best_pattern = 0;
@@ -1854,7 +1826,7 @@ INTERNAL int zint_qrcode(struct zint_symbol *symbol, struct zint_seg segs[], con
    symbol->rows = size;

    for (i = 0; i < size; i++) {
-        int r = i * size;
+        const int r = i * size;
        for (j = 0; j < size; j++) {
            if (grid[r + j] & 0x01) {
                z_set_module(symbol, i, j);
@@ -1981,11 +1953,10 @@ static void microqr_setup_grid(unsigned char *grid, const int size) {


    /* Reserve space for format information */
-    for (i = 0; i < 8; i++) {
+    for (i = 1; i <= 8; i++) {
        grid[(8 * size) + i] |= 0x20;
        grid[(i * size) + 8] |= 0x20;
    }
-    grid[(8 * size) + 8] |= 20;
 }

 static void microqr_populate_grid(unsigned char *grid, const int size, const char full_stream[], int bp) {
@@ -2063,36 +2034,23 @@ static int microqr_evaluate(const unsigned char *grid, const int size, const int

 static int microqr_apply_bitmask(unsigned char *grid, const int size, const int user_mask, const int debug_print) {
    int x, y;
-    int r, k;
+    int k;
    int bit;
    int pattern, value[4];
    int best_pattern;
-    int size_squared = size * size;
+    const int size_squared = size * size;
    unsigned char *mask = (unsigned char *) z_alloca(size_squared);
    unsigned char *eval = (unsigned char *) z_alloca(size_squared);

    /* Perform data masking */
    memset(mask, 0, size_squared);
    for (y = 0; y < size; y++) {
-        r = y * size;
+        const int ymod = y % 12;
+        const int r = y * size;
        for (x = 0; x < size; x++) {

            if (!(grid[r + x] & 0xF0)) {
-                if ((y & 1) == 0) {
-                    mask[r + x] |= 0x01;
-                }
-
-                if (((y / 2 + x / 3) & 1) == 0) {
-                    mask[r + x] |= 0x02;
-                }
-
-                if (((((y * x) & 1) + (y * x) % 3) & 1) == 0) {
-                    mask[r + x] |= 0x04;
-                }
-
-                if (((((y + x) & 1) + (y * x) % 3) & 1) == 0) {
-                    mask[r + x] |= 0x08;
-                }
+                mask[r + x] = microqr_masks[ymod][x % 6]; /* Pre-calculated table ala BWIPP, see "qr.h" */
            }
        }
    }
--- a/backend/qr.h
+++ b/backend/qr.h
@@ -1,7 +1,7 @@
 /* qr.h Data for QR Code, Micro QR Code and rMQR */
 /*
    libzint - the open source barcode library
-    Copyright (C) 2008-2024 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2008-2026 Robin Stuart <rstuart114@gmail.com>
    Copyright (C) 2006 Kentaro Fukuchi <fukuchi@megaui.net>

    Redistribution and use in source and binary forms, with or without
@@ -335,5 +335,42 @@ static const unsigned int rmqr_format_info_right[64] = {
    0x1CFB4, 0x1D091, 0x1EEDB, 0x1F1FE
 };

+/* Pre-calculated QR and MicroQR mask tables, generated by "backend/tools/gen_qr_masks.php",
+   based on lowest common periodicy of the masks (6x12):
+   QR: 000: 2x2, 001: 1x2, 010: 3x1, 011: 3x3, 100: 6x4, 101: 6x6, 110: 6x6, 111: 6x6
+   MicroQR: 00 (001), 01 (100), 10 (110), 11 (111)
+   Taken from Barcode Writer in Pure PostScript (BWIPP)
+   Copyright (c) 2004-2026 Terry Burton */
+/* SPDX-License-Identifier: MIT */
+static const unsigned char qr_masks[12][6] = {
+    { 0xFF, 0x72, 0xF3, 0x6E, 0xE3, 0x62 },
+    { 0x74, 0x51, 0x58, 0x85, 0x80, 0x89 },
+    { 0xE7, 0x4A, 0x03, 0x76, 0xDB, 0x92 },
+    { 0x6C, 0x81, 0x60, 0x9D, 0x70, 0x91 },
+    { 0xF7, 0x92, 0xDB, 0x66, 0x03, 0x4A },
+    { 0x74, 0x99, 0x90, 0x85, 0x48, 0x41 },
+    { 0xEF, 0x62, 0xE3, 0x7E, 0xF3, 0x72 },
+    { 0x64, 0x41, 0x48, 0x95, 0x90, 0x99 },
+    { 0xF7, 0x5A, 0x13, 0x66, 0xCB, 0x82 },
+    { 0x7C, 0x91, 0x70, 0x8D, 0x60, 0x81 },
+    { 0xE7, 0x82, 0xCB, 0x76, 0x13, 0x5A },
+    { 0x64, 0x89, 0x80, 0x95, 0x58, 0x51 }
+};
+
+static const unsigned char microqr_masks[12][6] = {
+    { 0x0F, 0x07, 0x0F, 0x05, 0x0D, 0x05 },
+    { 0x06, 0x06, 0x06, 0x08, 0x08, 0x08 },
+    { 0x0D, 0x05, 0x01, 0x07, 0x0F, 0x0B },
+    { 0x04, 0x08, 0x04, 0x0A, 0x06, 0x0A },
+    { 0x0F, 0x0B, 0x0F, 0x05, 0x01, 0x05 },
+    { 0x06, 0x0A, 0x0A, 0x08, 0x04, 0x04 },
+    { 0x0D, 0x05, 0x0D, 0x07, 0x0F, 0x07 },
+    { 0x04, 0x04, 0x04, 0x0A, 0x0A, 0x0A },
+    { 0x0F, 0x07, 0x03, 0x05, 0x0D, 0x09 },
+    { 0x06, 0x0A, 0x06, 0x08, 0x04, 0x08 },
+    { 0x0D, 0x09, 0x0D, 0x07, 0x03, 0x07 },
+    { 0x04, 0x08, 0x08, 0x0A, 0x06, 0x06 }
+};
+
 /* vim: set ts=4 sw=4 et : */
 #endif /* Z_QR_H */
--- a/backend/tests/tools/bwipp_dump.ps.tar.xz
+++ b/backend/tests/tools/bwipp_dump.ps.tar.xz
--- a/backend/tools/gen_qr_masks.php
+++ b/backend/tools/gen_qr_masks.php
@@ -0,0 +1,80 @@
+<?php
+/* Generate pre-calculated `qr_masks[]` for "qr.h" */
+/*
+    libzint - the open source barcode library
+    Copyright (C) 2026 Robin Stuart <rstuart114@gmail.com>
+*/
+/* SPDX-License-Identifier: BSD-3-Clause */
+
+/* Taken from Barcode Writer in Pure PostScript (BWIPP)
+   Copyright (c) 2004-2026 Terry Burton */
+/* SPDX-License-Identifier: MIT */
+
+/* See https://sourceforge.net/p/zint/mailman/message/59278637/
+   and https://github.com/bwipp/postscriptbarcode/commit/763fb4ffbfad7b379723dd3570183c769b28c786
+   and "Pre-calculated QR and MicroQR tables" comment in "qr.h"
+   
+   Paste output after comment
+*/
+
+$qr_masks = array();
+$mqr_masks = array();
+
+for ($y = 0; $y < 12; $y++) {
+    for ($x = 0; $x < 6; $x++) {
+        $bits = 0;
+        $mbits = 0;
+        if (($y + $x) % 2 === 0) { /* QR 000, period 2x2 */
+            $bits |= 0x01;
+        }
+        if ($y % 2 === 0) { /* QR 001, MicroQR 00, period 1x2 */
+            $bits |= 0x02;
+            $mbits |= 0x01;
+        }
+        if ($x % 3 === 0) { /* QR 010, period 3x1 */
+            $bits |= 0x04;
+        }
+        if (($y + $x) % 3 === 0) { /* QR 011, period 3x3 */
+            $bits |= 0x08;
+        }
+        if (((int)($y / 2) + (int)($x / 3)) % 2 === 0) { /* QR 100, MicroQR 01, period 6x4 */
+            $bits |= 0x10;
+            $mbits |= 0x02;
+        }
+        if ((($y * $x) % 2 + ($y * $x) % 3) === 0) { /* QR 101, period 6x6 */
+            $bits |= 0x20;
+        }
+        if ((($y * $x) % 2 + ($y * $x) % 3) % 2 === 0) { /* QR 110, MicroQR 10, period 6x6 */
+            $bits |= 0x40;
+            $mbits |= 0x04;
+        }
+        if ((($y + $x) % 2 + ($y * $x) % 3) % 2 === 0) { /* QR 111, MicroQR 11, period 6x6 */
+            $bits |= 0x80;
+            $mbits |= 0x08;
+        }
+        $qr_masks[$y][$x] = $bits;
+        $mqr_masks[$y][$x] = $mbits;
+    }
+}
+
+printf("static const unsigned char qr_masks[12][6] = {\n");
+for ($y = 0; $y < 12; $y++) {
+    printf("    { ");
+    for ($x = 0; $x < 6; $x++) {
+        printf("0x%02X%s", $qr_masks[$y][$x], $x == 5 ? " " : ", ");
+    }
+    printf("}%s\n", $y == 11 ? "" : ",");
+}
+printf("};\n");
+
+printf("\nstatic const unsigned char microqr_masks[12][6] = {\n");
+for ($y = 0; $y < 12; $y++) {
+    printf("    { ");
+    for ($x = 0; $x < 6; $x++) {
+        printf("0x%02X%s", $mqr_masks[$y][$x], $x == 5 ? " " : ", ");
+    }
+    printf("}%s\n", $y == 11 ? "" : ",");
+}
+printf("};\n");
+
+/* vim: set ts=4 sw=4 et : */