forked from mirror/vulkan-zig
76 lines
2.2 KiB
Zig
76 lines
2.2 KiB
Zig
pub fn Flags(comptime E: type) type {
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comptime {
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var bits: u32 = 0;
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inline for (@typeInfo(E).Enum.fields) |field| {
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const val: u32 = field.value;
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std.debug.assert(@popCount(u32, val) == 1);
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std.debug.assert(bits & val == 0);
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bits |= val;
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}
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}
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return struct {
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const Self = @This();
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bits: u32,
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pub const none = Self.init(.{});
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pub const all = comptime blk: {
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var flags = Self.none;
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inline for (@typeInfo(E).Enum.fields) |field| {
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flags.bits |= field.value;
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}
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break :blk flags;
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};
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pub fn init(flags: var) Self {
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return .{.bits = Self.toBits(flags)};
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}
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pub fn merge(lhs: Self, rhs: Self) Self {
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return .{.bits = lhs.bits | rhs.bits};
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}
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pub fn intersect(lhs: Self, rhs: Self) Self {
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return .{.bits = lhs.bits & rhs.bits};
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}
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pub fn subtract(lhs: Self, rhs: Self) Self {
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return .{.bits = lhs.bits & rhs.complement().bits};
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}
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pub fn complement(self: Self) Self {
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return .{.bits = ~self.bits & Self.all.bits};
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}
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pub fn contains(lhs: Self, rhs: Self) bool {
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return lhs.bits & rhs.bits == rhs.bits;
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}
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pub fn equals(lhs: Self, rhs: Self) bool {
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return lhs.bits == rhs.bits;
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}
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fn toBits(flags: var) u32 {
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const ty = @TypeOf(flags);
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if (ty == Self) {
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return flags.bits;
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}
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switch (@typeInfo(ty)) {
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.EnumLiteral => return @enumToInt(@as(E, flags)),
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.Struct => |struct_info| {
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var value: u32 = 0;
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inline for (struct_info.fields) |field| {
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value |= @enumToInt(@as(E, @field(flags, field.name)));
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}
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return value;
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},
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else => @compileError("Value of type '" ++ @typeName(ty)
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++ "' cannot be converted into '" ++ @typeName(Self) ++ "'")
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}
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}
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};
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}
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