refactor: avoid unnecessary @intCast and @ptrCast in FontFace.zig

closes #275

src/win32/FontFace.zig

@@ -2,29 +2,31 @@ const FontFace = @This();
 
 const std = @import("std");
 
-// it seems that Windows only supports font faces with up to 31 characters
-pub const max = 31;
+// it seems that Windows only supports font faces with up to 31 characters,
+// but we use a larger buffer here because GetFamilyNames can apparently
+// return longer strings
+pub const max = 254;
 
 buf: [max + 1]u16,
-len: u5,
+len: usize,
 
 pub fn initUtf8(utf8: []const u8) error{ TooLong, InvalidUtf8 }!FontFace {
     const utf16_len = std.unicode.calcUtf16LeLen(utf8) catch return error.InvalidUtf8;
     if (utf16_len > max)
         return error.TooLong;
-    var result: FontFace = .{ .buf = undefined, .len = @intCast(utf16_len) };
-    result.buf[utf16_len] = 0;
-    const actual_len = try std.unicode.utf8ToUtf16Le(&result.buf, utf8);
+    var self: FontFace = .{ .buf = undefined, .len = utf16_len };
+    const actual_len = try std.unicode.utf8ToUtf16Le(&self.buf, utf8);
     std.debug.assert(actual_len == utf16_len);
-    return result;
+    self.buf[actual_len] = 0;
+    return self;
 }
 
 pub fn ptr(self: *const FontFace) [*:0]const u16 {
-    std.debug.assert(self.buf[@as(usize, self.len)] == 0);
-    return @ptrCast(&self.buf);
+    return self.slice().ptr;
 }
 pub fn slice(self: *const FontFace) [:0]const u16 {
-    return self.ptr()[0..self.len :0];
+    std.debug.assert(self.buf[self.len] == 0);
+    return self.buf[0..self.len :0];
 }
 pub fn eql(self: *const FontFace, other: *const FontFace) bool {
     return std.mem.eql(u16, self.slice(), other.slice());