From a3624e94f812efaae40d2ca66da0b49ca63cb936 Mon Sep 17 00:00:00 2001 From: Vexu Date: Mon, 14 Sep 2020 23:53:38 +0300 Subject: translate-c: determine sizeof using std.meta.sizeof --- lib/std/meta.zig | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'lib/std/meta.zig') diff --git a/lib/std/meta.zig b/lib/std/meta.zig index b0c1aadd91..1507aa9de8 100644 --- a/lib/std/meta.zig +++ b/lib/std/meta.zig @@ -795,3 +795,34 @@ test "std.meta.cast" { testing.expectEqual(@as(u32, 10), cast(u32, @as(u64, 10))); testing.expectEqual(@as(u8, 2), cast(u8, E.Two)); } + +/// Given a value returns its size as C's sizeof operator would. +/// This is for translate-c and is not intended for general use. +pub fn sizeof(target: anytype) usize { + switch (@typeInfo(@TypeOf(target))) { + .Type => return @sizeOf(target), + .Float, .Int, .Struct, .Union, .Enum => return @sizeOf(@TypeOf(target)), + .ComptimeFloat => return @sizeOf(f64), // TODO c_double #3999 + .ComptimeInt => { + // TODO to get the correct result we have to translate + // `1073741824 * 4` as `int(1073741824) *% int(4)` since + // sizeof(1073741824 * 4) != sizeof(4294967296). + + // TODO test if target fits in int, long or long long + return @sizeOf(c_int); + }, + else => @compileError("TODO implement std.meta.sizeof for type " ++ @typeName(@TypeOf(target))), + } +} + +test "sizeof" { + const E = extern enum(c_int) { One, _ }; + const S = extern struct { a: u32 }; + + testing.expect(sizeof(u32) == 4); + testing.expect(sizeof(@as(u32, 2)) == 4); + testing.expect(sizeof(2) == @sizeOf(c_int)); + testing.expect(sizeof(E) == @sizeOf(c_int)); + testing.expect(sizeof(E.One) == @sizeOf(c_int)); + testing.expect(sizeof(S) == 4); +} -- cgit v1.2.3