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-rw-r--r--src/shared/qrcode-util.c119
1 files changed, 119 insertions, 0 deletions
diff --git a/src/shared/qrcode-util.c b/src/shared/qrcode-util.c
new file mode 100644
index 0000000..4a33c28
--- /dev/null
+++ b/src/shared/qrcode-util.c
@@ -0,0 +1,119 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "qrcode-util.h"
+
+#if HAVE_QRENCODE
+#include <qrencode.h>
+
+#include "dlfcn-util.h"
+#include "locale-util.h"
+#include "log.h"
+#include "strv.h"
+#include "terminal-util.h"
+
+#define ANSI_WHITE_ON_BLACK "\033[40;37;1m"
+#define UNICODE_FULL_BLOCK u8"█"
+#define UNICODE_LOWER_HALF_BLOCK u8"▄"
+#define UNICODE_UPPER_HALF_BLOCK u8"▀"
+
+static void *qrcode_dl = NULL;
+
+static QRcode* (*sym_QRcode_encodeString)(const char *string, int version, QRecLevel level, QRencodeMode hint, int casesensitive) = NULL;
+static void (*sym_QRcode_free)(QRcode *qrcode) = NULL;
+
+int dlopen_qrencode(void) {
+ int r;
+
+ FOREACH_STRING(s, "libqrencode.so.4", "libqrencode.so.3") {
+ r = dlopen_many_sym_or_warn(
+ &qrcode_dl, s, LOG_DEBUG,
+ DLSYM_ARG(QRcode_encodeString),
+ DLSYM_ARG(QRcode_free));
+ if (r >= 0)
+ break;
+ }
+
+ return r;
+}
+
+static void print_border(FILE *output, unsigned width) {
+ /* Four rows of border */
+ for (unsigned y = 0; y < 4; y += 2) {
+ fputs(ANSI_WHITE_ON_BLACK, output);
+
+ for (unsigned x = 0; x < 4 + width + 4; x++)
+ fputs(UNICODE_FULL_BLOCK, output);
+
+ fputs(ANSI_NORMAL "\n", output);
+ }
+}
+
+static void write_qrcode(FILE *output, QRcode *qr) {
+ assert(qr);
+
+ if (!output)
+ output = stdout;
+
+ print_border(output, qr->width);
+
+ for (unsigned y = 0; y < (unsigned) qr->width; y += 2) {
+ const uint8_t *row1 = qr->data + qr->width * y;
+ const uint8_t *row2 = row1 + qr->width;
+
+ fputs(ANSI_WHITE_ON_BLACK, output);
+ for (unsigned x = 0; x < 4; x++)
+ fputs(UNICODE_FULL_BLOCK, output);
+
+ for (unsigned x = 0; x < (unsigned) qr->width; x++) {
+ bool a, b;
+
+ a = row1[x] & 1;
+ b = (y+1) < (unsigned) qr->width ? (row2[x] & 1) : false;
+
+ if (a && b)
+ fputc(' ', output);
+ else if (a)
+ fputs(UNICODE_LOWER_HALF_BLOCK, output);
+ else if (b)
+ fputs(UNICODE_UPPER_HALF_BLOCK, output);
+ else
+ fputs(UNICODE_FULL_BLOCK, output);
+ }
+
+ for (unsigned x = 0; x < 4; x++)
+ fputs(UNICODE_FULL_BLOCK, output);
+ fputs(ANSI_NORMAL "\n", output);
+ }
+
+ print_border(output, qr->width);
+ fflush(output);
+}
+
+int print_qrcode(FILE *out, const char *header, const char *string) {
+ QRcode* qr;
+ int r;
+
+ /* If this is not an UTF-8 system or ANSI colors aren't supported/disabled don't print any QR
+ * codes */
+ if (!is_locale_utf8() || !colors_enabled())
+ return -EOPNOTSUPP;
+
+ r = dlopen_qrencode();
+ if (r < 0)
+ return r;
+
+ qr = sym_QRcode_encodeString(string, 0, QR_ECLEVEL_L, QR_MODE_8, 1);
+ if (!qr)
+ return -ENOMEM;
+
+ if (header)
+ fprintf(out, "\n%s:\n\n", header);
+
+ write_qrcode(out, qr);
+
+ fputc('\n', out);
+
+ sym_QRcode_free(qr);
+ return 0;
+}
+#endif