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const std = @import("std");
/// An enum(u16) of the available device status requests.
pub const Request = dsr_enum: {
const EnumField = std.builtin.Type.EnumField;
var fields: [entries.len]EnumField = undefined;
for (entries, 0..) |entry, i| {
fields[i] = .{
.name = entry.name,
.value = @as(Tag.Backing, @bitCast(Tag{
.value = entry.value,
.question = entry.question,
})),
};
}
break :dsr_enum @Type(.{ .@"enum" = .{
.tag_type = Tag.Backing,
.fields = &fields,
.decls = &.{},
.is_exhaustive = true,
} });
};
/// The tag type for our enum is a u16 but we use a packed struct
/// in order to pack the question bit into the tag. The "u16" size is
/// chosen somewhat arbitrarily to match the largest expected size
/// we see as a multiple of 8 bits.
pub const Tag = packed struct(u16) {
pub const Backing = @typeInfo(@This()).@"struct".backing_integer.?;
value: u15,
question: bool = false,
test "order" {
const t: Tag = .{ .value = 1 };
const int: Backing = @bitCast(t);
try std.testing.expectEqual(@as(Backing, 1), int);
}
};
pub fn reqFromInt(v: u16, question: bool) ?Request {
inline for (entries) |entry| {
if (entry.value == v and entry.question == question) {
const tag: Tag = .{ .question = question, .value = entry.value };
const int: Tag.Backing = @bitCast(tag);
return @enumFromInt(int);
}
}
return null;
}
/// A single entry of a possible device status request we support. The
/// "question" field determines if it is valid with or without the "?"
/// prefix.
const Entry = struct {
name: [:0]const u8,
value: comptime_int,
question: bool = false, // "?" request
};
/// The full list of device status request entries.
const entries: []const Entry = &.{
.{ .name = "operating_status", .value = 5 },
.{ .name = "cursor_position", .value = 6 },
.{ .name = "color_scheme", .value = 996, .question = true },
};
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