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const std = @import("std");
const bun = @import("bun");
const string = bun.string;
const Output = bun.Output;
const Global = bun.Global;
const Environment = bun.Environment;
const strings = bun.strings;
const default_allocator = bun.default_allocator;
const C = bun.C;
const typeBaseName = @import("./meta.zig").typeBaseName;
const TagSize = u15;
const AddressableSize = u49;
pub const TaggedPointer = packed struct {
_ptr: AddressableSize,
data: TagSize,
pub inline fn init(ptr: anytype, data: TagSize) TaggedPointer {
const Ptr = @TypeOf(ptr);
if (comptime @typeInfo(Ptr) != .Pointer and Ptr != ?*anyopaque) {
@compileError(@typeName(Ptr) ++ " must be a ptr, received: " ++ @tagName(@typeInfo(Ptr)));
}
const address = @ptrToInt(ptr);
return TaggedPointer{
._ptr = @truncate(AddressableSize, address),
.data = data,
};
}
pub inline fn get(this: TaggedPointer, comptime Type: type) *Type {
return @intToPtr(*Type, @intCast(usize, this._ptr));
}
pub inline fn from(val: anytype) TaggedPointer {
const ValueType = @TypeOf(val);
return switch (ValueType) {
f64, i64, u64 => @bitCast(TaggedPointer, val),
?*anyopaque, *anyopaque => @bitCast(TaggedPointer, @ptrToInt(val)),
else => @compileError("Unsupported type: " ++ @typeName(ValueType)),
};
}
pub inline fn to(this: TaggedPointer) *anyopaque {
return @intToPtr(*anyopaque, @bitCast(u64, this));
}
};
pub fn TaggedPointerUnion(comptime Types: anytype) type {
const TagType: type = tag_break: {
if (std.meta.trait.isIndexable(@TypeOf(Types))) {
var enumFields: [Types.len]std.builtin.Type.EnumField = undefined;
var decls = [_]std.builtin.Type.Declaration{};
inline for (Types) |field, i| {
enumFields[i] = .{
.name = comptime typeBaseName(@typeName(field)),
.value = 1024 - i,
};
}
break :tag_break @Type(.{
.Enum = .{
.tag_type = TagSize,
.fields = &enumFields,
.decls = &decls,
.is_exhaustive = false,
},
});
} else {
const Fields: []const std.builtin.Type.StructField = std.meta.fields(@TypeOf(Types));
var enumFields: [Fields.len]std.builtin.Type.EnumField = undefined;
var decls = [_]std.builtin.Type.Declaration{};
inline for (Fields) |field, i| {
enumFields[i] = .{
.name = comptime typeBaseName(@typeName(field.default_value.?)),
.value = 1024 - i,
};
}
break :tag_break @Type(.{
.Enum = .{
.tag_type = TagSize,
.fields = &enumFields,
.decls = &decls,
.is_exhaustive = false,
},
});
}
};
return struct {
pub const Tag = TagType;
repr: TaggedPointer,
const This = @This();
fn assert_type(comptime Type: type) void {
var name = comptime typeBaseName(@typeName(Type));
if (!comptime @hasField(Tag, name)) {
@compileError("TaggedPointerUnion does not have " ++ name ++ ".");
}
}
pub inline fn get(this: This, comptime Type: anytype) ?*Type {
comptime assert_type(Type);
return if (this.is(Type)) this.as(Type) else null;
}
pub inline fn tag(this: This) TagType {
return @intToEnum(TagType, this.repr.data);
}
/// unsafely cast a tagged pointer to a specific type, without checking that it's really that type
pub inline fn as(this: This, comptime Type: type) *Type {
comptime assert_type(Type);
return this.repr.get(Type);
}
pub inline fn is(this: This, comptime Type: type) bool {
comptime assert_type(Type);
return this.repr.data == comptime @enumToInt(@field(Tag, typeBaseName(@typeName(Type))));
}
pub fn set(this: *@This(), _ptr: anytype) void {
this.* = @This().init(_ptr);
}
pub inline fn isValidPtr(_ptr: ?*anyopaque) bool {
return This.isValid(This.from(_ptr));
}
pub inline fn isValid(this: This) bool {
return switch (this.repr.data) {
@enumToInt(
@field(Tag, typeBaseName(@typeName(Types[Types.len - 1]))),
)...@enumToInt(
@field(Tag, typeBaseName(@typeName(Types[0]))),
) => true,
else => false,
};
}
pub inline fn from(_ptr: ?*anyopaque) This {
return This{ .repr = TaggedPointer.from(_ptr) };
}
pub inline fn ptr(this: This) *anyopaque {
return this.repr.to();
}
pub inline fn ptrUnsafe(this: This) *anyopaque {
@setRuntimeSafety(false);
return this.repr.to();
}
pub inline fn init(_ptr: anytype) This {
const Type = std.meta.Child(@TypeOf(_ptr));
const name = comptime typeBaseName(@typeName(Type));
// there will be a compiler error if the passed in type doesn't exist in the enum
return This{ .repr = TaggedPointer.init(_ptr, @enumToInt(@field(Tag, name))) };
}
};
}
test "TaggedPointerUnion" {
const IntPrimitive = struct { val: u32 = 0 };
const StringPrimitive = struct { val: []const u8 = "" };
const Object = struct { blah: u32, val: u32 };
// const Invalid = struct {
// wrong: bool = true,
// };
const Union = TaggedPointerUnion(.{ IntPrimitive, StringPrimitive, Object });
var str = try default_allocator.create(StringPrimitive);
str.* = StringPrimitive{ .val = "hello!" };
var un = Union.init(str);
try std.testing.expect(un.is(StringPrimitive));
try std.testing.expectEqualStrings(un.as(StringPrimitive).val, "hello!");
try std.testing.expect(!un.is(IntPrimitive));
const num = try default_allocator.create(IntPrimitive);
num.val = 9999;
var un2 = Union.init(num);
try std.testing.expect(un2.as(IntPrimitive).val == 9999);
try std.testing.expect(un.tag() == .StringPrimitive);
try std.testing.expect(un2.tag() == .IntPrimitive);
un2.repr.data = 0;
try std.testing.expect(un2.tag() != .IntPrimitive);
try std.testing.expect(un2.get(IntPrimitive) == null);
// try std.testing.expect(un2.is(Invalid) == false);
}
test "TaggedPointer" {
const Hello = struct {
what: []const u8,
};
var hello_struct_ptr = try default_allocator.create(Hello);
hello_struct_ptr.* = Hello{ .what = "hiiii" };
var tagged = TaggedPointer.init(hello_struct_ptr, 0);
try std.testing.expectEqual(tagged.get(Hello), hello_struct_ptr);
try std.testing.expectEqualStrings(tagged.get(Hello).what, hello_struct_ptr.what);
tagged = TaggedPointer.init(hello_struct_ptr, 100);
try std.testing.expectEqual(tagged.get(Hello), hello_struct_ptr);
try std.testing.expectEqualStrings(tagged.get(Hello).what, hello_struct_ptr.what);
tagged = TaggedPointer.init(hello_struct_ptr, std.math.maxInt(TagSize) - 500);
try std.testing.expectEqual(tagged.get(Hello), hello_struct_ptr);
try std.testing.expectEqual(tagged.data, std.math.maxInt(TagSize) - 500);
try std.testing.expectEqualStrings(tagged.get(Hello).what, hello_struct_ptr.what);
var i: TagSize = 0;
while (i < std.math.maxInt(TagSize) - 1) : (i += 1) {
hello_struct_ptr = try default_allocator.create(Hello);
const what = try std.fmt.allocPrint(default_allocator, "hiiii {d}", .{i});
hello_struct_ptr.* = Hello{ .what = what };
try std.testing.expectEqualStrings(TaggedPointer.from(TaggedPointer.init(hello_struct_ptr, i).to()).get(Hello).what, what);
var this = TaggedPointer.from(TaggedPointer.init(hello_struct_ptr, i).to());
try std.testing.expect(this.data == i);
try std.testing.expect(this.data != i + 1);
}
}
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