1 files changed, 38 insertions, 0 deletions
diff --git a/vendor/libghostty-vt/src/terminal/osc/encoding.zig b/vendor/libghostty-vt/src/terminal/osc/encoding.zig
new file mode 100644
index 00000000..7491d10c
--- /dev/null
+++ b/vendor/libghostty-vt/src/terminal/osc/encoding.zig
@@ -0,0 +1,38 @@
+//! Specialized encodings used in some OSC protocols.
+const std = @import("std");
+
+/// Kitty defines "Escape code safe UTF-8" as valid UTF-8 with the
+/// additional requirement of not containing any C0 escape codes
+/// (0x00-0x1f), DEL (0x7f) and C1 escape codes (0x80-0x9f).
+///
+/// Used by OSC 66 (text sizing) and OSC 99 (Kitty notifications).
+///
+/// See: https://sw.kovidgoyal.net/kitty/desktop-notifications/#safe-utf8
+pub fn isSafeUtf8(s: []const u8) bool {
+    const utf8 = std.unicode.Utf8View.init(s) catch {
+        @branchHint(.cold);
+        return false;
+    };
+
+    var it = utf8.iterator();
+    while (it.nextCodepoint()) |cp| switch (cp) {
+        0x00...0x1f, 0x7f, 0x80...0x9f => {
+            @branchHint(.cold);
+            return false;
+        },
+        else => {},
+    };
+
+    return true;
+}
+
+test isSafeUtf8 {
+    const testing = std.testing;
+
+    try testing.expect(isSafeUtf8("Hello world!"));
+    try testing.expect(isSafeUtf8("安全的ユニコード☀️"));
+    try testing.expect(!isSafeUtf8("No linebreaks\nallowed"));
+    try testing.expect(!isSafeUtf8("\x07no bells"));
+    try testing.expect(!isSafeUtf8("\x1b]9;no OSCs\x1b\\\x1b[m"));
+    try testing.expect(!isSafeUtf8("\x9f8-bit escapes are clever, but no"));
+}