use DEC graphics instead of Unicode for box drawing

1 files changed, 30 insertions, 0 deletions

diff --git a/lib/std/debug.zig b/lib/std/debug.zig
index 3c5f6d2edf..6abceed9b8 100644
--- a/lib/std/debug.zig
+++ b/lib/std/debug.zig
@@ -685,6 +685,36 @@ pub const TTY = struct {
                 },
             };
         }
+
+        pub fn writeDEC(conf: Config, writer: anytype, codepoint: u8) !void {
+            const bytes = switch (conf) {
+                .no_color, .windows_api => switch (codepoint) {
+                    0x50...0x5e => @as(*const [1]u8, &codepoint),
+                    0x6a => "+", // ┘
+                    0x6b => "+", // ┐
+                    0x6c => "+", // ┌
+                    0x6d => "+", // └
+                    0x6e => "+", // ┼
+                    0x71 => "-", // ─
+                    0x74 => "+", // ├
+                    0x75 => "+", // ┤
+                    0x76 => "+", // ┴
+                    0x77 => "+", // ┬
+                    0x78 => "|", // │
+                    else => " ", // TODO
+                },
+                .escape_codes => switch (codepoint) {
+                    // Here we avoid writing the DEC beginning sequence and
+                    // ending sequence in separate syscalls by putting the
+                    // beginning and ending sequence into the same string
+                    // literals, to prevent terminals ending up in bad states
+                    // in case a crash happens between syscalls.
+                    inline 0x50...0x7f => |x| "\x1B\x28\x30" ++ [1]u8{x} ++ "\x1B\x28\x42",
+                    else => unreachable,
+                },
+            };
+            return writer.writeAll(bytes);
+        }
     };
 };