diff --git a/src/main.zig b/src/main.zig index 1c86b86..f6e9111 100644 --- a/src/main.zig +++ b/src/main.zig @@ -42,7 +42,7 @@ pub fn main() !void { const prefix = "/dev/ttyUSB"; const device = try alloc.dupeZ(u8, args[1]); defer alloc.free(device); - if (!std.mem.startsWith(u8, device, prefix)) try usage(args); + if (!std.mem.eql(u8, device, "-") and !std.mem.startsWith(u8, device, prefix)) try usage(args); // stdout is for the actual output of your application, for example if you // are implementing gzip, then only the compressed bytes should be sent to @@ -69,7 +69,7 @@ pub fn main() !void { filename = args[i]; // arg capture changes value... break; } - if (arg[0] == '-' and areDigits(arg[1..])) { + if ((arg[0] == '-' and arg.len > 1) and areDigits(arg[1..])) { line_number = try std.fmt.parseInt(usize, arg[1..], 10); continue; } @@ -116,6 +116,9 @@ fn areDigits(bytes: []u8) bool { } fn sendPixels(pixels: []const u8, file: [:0]const u8, device_id: u8) !void { + if (std.mem.eql(u8, file, "-")) + return sendPixelsToStdOut(pixels); + if (@import("builtin").os.tag != .linux) @compileError("Linux only please!"); @@ -127,6 +130,16 @@ fn sendPixels(pixels: []const u8, file: [:0]const u8, device_id: u8) !void { return error.LinuxNativeNotImplemented; } +fn sendPixelsToStdOut(pixels: []const u8) !void { + const stdout_file = std.io.getStdOut().writer(); + var bw = std.io.bufferedWriter(stdout_file); + const stdout = bw.writer(); + defer bw.flush() catch unreachable; // don't forget to flush! + for (0..HEIGHT) |i| { + try stdout.print("{d:0>2}: {s}\n", .{ i, fmtSliceGreyscaleImage(pixels[(i * WIDTH)..((i + 1) * WIDTH)]) }); + } +} + fn sendPixelsThroughI2CDriver(pixels: []const u8, file: [*:0]const u8, device_id: u8) !void { var pixels_write_command = [_]u8{0x00} ** ((WIDTH * PAGES) + 1); pixels_write_command[0] = 0x40;