1 files changed, 121 insertions, 0 deletions
diff --git a/src/journal/journal-qrcode.c b/src/journal/journal-qrcode.c
new file mode 100644
index 0000000..35d6ec4
--- /dev/null
+++ b/src/journal/journal-qrcode.c
@@ -0,0 +1,121 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <errno.h>
+#include <qrencode.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdio_ext.h>
+#include <stdlib.h>
+
+#include "journal-qrcode.h"
+#include "macro.h"
+
+#define WHITE_ON_BLACK "\033[40;37;1m"
+#define NORMAL "\033[0m"
+
+static void print_border(FILE *output, unsigned width) {
+        unsigned x, y;
+
+        /* Four rows of border */
+        for (y = 0; y < 4; y += 2) {
+                fputs(WHITE_ON_BLACK, output);
+
+                for (x = 0; x < 4 + width + 4; x++)
+                        fputs("\342\226\210", output);
+
+                fputs(NORMAL "\n", output);
+        }
+}
+
+int print_qr_code(
+                FILE *output,
+                const void *seed,
+                size_t seed_size,
+                uint64_t start,
+                uint64_t interval,
+                const char *hn,
+                sd_id128_t machine) {
+
+        FILE *f;
+        char *url = NULL;
+        size_t url_size = 0, i;
+        QRcode* qr;
+        unsigned x, y;
+
+        assert(seed);
+        assert(seed_size > 0);
+
+        f = open_memstream(&url, &url_size);
+        if (!f)
+                return -ENOMEM;
+
+        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+
+        fputs("fss://", f);
+
+        for (i = 0; i < seed_size; i++) {
+                if (i > 0 && i % 3 == 0)
+                        fputc('-', f);
+                fprintf(f, "%02x", ((uint8_t*) seed)[i]);
+        }
+
+        fprintf(f, "/%"PRIx64"-%"PRIx64"?machine=" SD_ID128_FORMAT_STR,
+                start,
+                interval,
+                SD_ID128_FORMAT_VAL(machine));
+
+        if (hn)
+                fprintf(f, ";hostname=%s", hn);
+
+        if (ferror(f)) {
+                fclose(f);
+                free(url);
+                return -ENOMEM;
+        }
+
+        fclose(f);
+
+        qr = QRcode_encodeString(url, 0, QR_ECLEVEL_L, QR_MODE_8, 1);
+        free(url);
+
+        if (!qr)
+                return -ENOMEM;
+
+        print_border(output, qr->width);
+
+        for (y = 0; y < (unsigned) qr->width; y += 2) {
+                const uint8_t *row1, *row2;
+
+                row1 = qr->data + qr->width * y;
+                row2 = row1 + qr->width;
+
+                fputs(WHITE_ON_BLACK, output);
+                for (x = 0; x < 4; x++)
+                        fputs("\342\226\210", output);
+
+                for (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("\342\226\204", output);
+                        else if (b)
+                                fputs("\342\226\200", output);
+                        else
+                                fputs("\342\226\210", output);
+                }
+
+                for (x = 0; x < 4; x++)
+                        fputs("\342\226\210", output);
+                fputs(NORMAL "\n", output);
+        }
+
+        print_border(output, qr->width);
+
+        QRcode_free(qr);
+        return 0;
+}