1 files changed, 79 insertions, 0 deletions
diff --git a/src/basic/bus-label.c b/src/basic/bus-label.c
new file mode 100644
index 0000000..d33fc92
--- /dev/null
+++ b/src/basic/bus-label.c
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <stdlib.h>
+
+#include "alloc-util.h"
+#include "bus-label.h"
+#include "hexdecoct.h"
+#include "macro.h"
+
+char *bus_label_escape(const char *s) {
+        char *r, *t;
+        const char *f;
+
+        assert_return(s, NULL);
+
+        /* Escapes all chars that D-Bus' object path cannot deal
+         * with. Can be reversed with bus_path_unescape(). We special
+         * case the empty string. */
+
+        if (*s == 0)
+                return strdup("_");
+
+        r = new(char, strlen(s)*3 + 1);
+        if (!r)
+                return NULL;
+
+        for (f = s, t = r; *f; f++) {
+
+                /* Escape everything that is not a-zA-Z0-9. We also escape 0-9 if it's the first character */
+
+                if (!ascii_isalpha(*f) &&
+                    !(f > s && ascii_isdigit(*f))) {
+                        *(t++) = '_';
+                        *(t++) = hexchar(*f >> 4);
+                        *(t++) = hexchar(*f);
+                } else
+                        *(t++) = *f;
+        }
+
+        *t = 0;
+
+        return r;
+}
+
+char *bus_label_unescape_n(const char *f, size_t l) {
+        char *r, *t;
+        size_t i;
+
+        assert_return(f, NULL);
+
+        /* Special case for the empty string */
+        if (l == 1 && *f == '_')
+                return strdup("");
+
+        r = new(char, l + 1);
+        if (!r)
+                return NULL;
+
+        for (i = 0, t = r; i < l; ++i) {
+                if (f[i] == '_') {
+                        int a, b;
+
+                        if (l - i < 3 ||
+                            (a = unhexchar(f[i + 1])) < 0 ||
+                            (b = unhexchar(f[i + 2])) < 0) {
+                                /* Invalid escape code, let's take it literal then */
+                                *(t++) = '_';
+                        } else {
+                                *(t++) = (char) ((a << 4) | b);
+                                i += 2;
+                        }
+                } else
+                        *(t++) = f[i];
+        }
+
+        *t = 0;
+
+        return r;
+}