From e0cfc13287abf746864d6e86176af691da0faa8a Mon Sep 17 00:00:00 2001
From: Intege-rs <me@jessiep.me>
Date: Tue, 25 Feb 2025 01:25:08 -0500
Subject: [PATCH] ctuple for small c structs

---
 sub/core/src/ctuple.rs | 75 ++++++++++++++++++++++++++++++++++++++++++
 sub/core/src/lib.rs    |  3 ++
 2 files changed, 78 insertions(+)
 create mode 100644 sub/core/src/ctuple.rs

diff --git a/sub/core/src/ctuple.rs b/sub/core/src/ctuple.rs
new file mode 100644
index 0000000..a285f02
--- /dev/null
+++ b/sub/core/src/ctuple.rs
@@ -0,0 +1,75 @@
+
+pub trait Tuple2CTuple {
+    type CTuple;
+}
+
+// We place each tuple inside its own module so that it rustrover hints simply show it as C<...>
+macro_rules! define_tuple {
+    ($struct_name:ident, $module_name:ident, $($T:ident),*) => {
+        pub mod $module_name {
+            #[repr(C)]
+            pub struct $struct_name<$($T),*>($(pub $T),*);
+
+            impl<$($T),*> super::Tuple2CTuple for ($($T,)*) {
+                type CTuple = $struct_name<$($T,)*>;
+            }
+        }
+    };
+}
+
+// @formatter:off
+define_tuple!(C, t0 , );
+define_tuple!(C, t1 , T0);
+define_tuple!(C, t2 , T0, T1);
+define_tuple!(C, t3 , T0, T1, T2);
+define_tuple!(C, t4 , T0, T1, T2, T3);
+define_tuple!(C, t5 , T0, T1, T2, T3, T4);
+define_tuple!(C, t6 , T0, T1, T2, T3, T4, T5);
+define_tuple!(C, t7 , T0, T1, T2, T3, T4, T5, T6);
+define_tuple!(C, t8 , T0, T1, T2, T3, T4, T5, T6, T7);
+define_tuple!(C, t9 , T0, T1, T2, T3, T4, T5, T6, T7, T8);
+define_tuple!(C, t10, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9);
+define_tuple!(C, t11, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10);
+define_tuple!(C, t12, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11);
+define_tuple!(C, t13, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12);
+define_tuple!(C, t14, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13);
+define_tuple!(C, t15, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14);
+define_tuple!(C, t16, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T16);
+// @formatter:on
+
+/// Helper macro to get the correct Tuple based on the number of arguments...
+pub macro find_type {
+    // @formatter:off
+    ()                                                                                                                                       => { $crate::ctuple::t0::C },
+    ($T0:tt)                                                                                                                                 => { $crate::ctuple::t1::C },
+    ($T0:tt, $T1:tt)                                                                                                                         => { $crate::ctuple::t2::C },
+    ($T0:tt, $T1:tt, $T2:tt)                                                                                                                 => { $crate::ctuple::t3::C },
+    ($T0:tt, $T1:tt, $T2:tt, $T3:tt)                                                                                                         => { $crate::ctuple::t4::C },
+    ($T0:tt, $T1:tt, $T2:tt, $T3:tt, $T4:tt)                                                                                                 => { $crate::ctuple::t5::C },
+    ($T0:tt, $T1:tt, $T2:tt, $T3:tt, $T4:tt, $T5:tt)                                                                                         => { $crate::ctuple::t6::C },
+    ($T0:tt, $T1:tt, $T2:tt, $T3:tt, $T4:tt, $T5:tt, $T6:tt)                                                                                 => { $crate::ctuple::t7::C },
+    ($T0:tt, $T1:tt, $T2:tt, $T3:tt, $T4:tt, $T5:tt, $T6:tt, $T7:tt)                                                                         => { $crate::ctuple::t8::C },
+    ($T0:tt, $T1:tt, $T2:tt, $T3:tt, $T4:tt, $T5:tt, $T6:tt, $T7:tt, $T8:tt)                                                                 => { $crate::ctuple::t9::C },
+    ($T0:tt, $T1:tt, $T2:tt, $T3:tt, $T4:tt, $T5:tt, $T6:tt, $T7:tt, $T8:tt, $T9:tt)                                                         => { $crate::ctuple::t10::C },
+    ($T0:tt, $T1:tt, $T2:tt, $T3:tt, $T4:tt, $T5:tt, $T6:tt, $T7:tt, $T8:tt, $T9:tt, $T10:tt)                                                => { $crate::ctuple::t11::C },
+    ($T0:tt, $T1:tt, $T2:tt, $T3:tt, $T4:tt, $T5:tt, $T6:tt, $T7:tt, $T8:tt, $T9:tt, $T10:tt, $T11:tt)                                       => { $crate::ctuple::t12::C },
+    ($T0:tt, $T1:tt, $T2:tt, $T3:tt, $T4:tt, $T5:tt, $T6:tt, $T7:tt, $T8:tt, $T9:tt, $T10:tt, $T11:tt, $T12:tt)                              => { $crate::ctuple::t13::C },
+    ($T0:tt, $T1:tt, $T2:tt, $T3:tt, $T4:tt, $T5:tt, $T6:tt, $T7:tt, $T8:tt, $T9:tt, $T10:tt, $T11:tt, $T12:tt, $T13:tt)                     => { $crate::ctuple::t14::C },
+    ($T0:tt, $T1:tt, $T2:tt, $T3:tt, $T4:tt, $T5:tt, $T6:tt, $T7:tt, $T8:tt, $T9:tt, $T10:tt, $T11:tt, $T12:tt, $T13:tt, $T14:tt)            => { $crate::ctuple::t15::C },
+    ($T0:tt, $T1:tt, $T2:tt, $T3:tt, $T4:tt, $T5:tt, $T6:tt, $T7:tt, $T8:tt, $T9:tt, $T10:tt, $T11:tt, $T12:tt, $T13:tt, $T14:tt, $T15:tt)   => { $crate::ctuple::t16::C },
+    // @formatter:on
+}
+
+#[allow(non_snake_case)]
+pub macro C {
+
+    // Simply use the Tuple2CTuple trait to convert the regular tuple to our ReprC variant
+    ($($types:ty),*) => {
+        <($($types,)*) as Tuple2CTuple>::CTuple
+    },
+
+    // use the auxiliary macro to find the correct tuple type and construct it
+    ($($values:expr),*) => {
+        $crate::ctuple::find_type!($($values),*)($($values),*)
+    },
+}
\ No newline at end of file
diff --git a/sub/core/src/lib.rs b/sub/core/src/lib.rs
index 007f7a0..891db75 100644
--- a/sub/core/src/lib.rs
+++ b/sub/core/src/lib.rs
@@ -25,6 +25,8 @@ pub mod pstruct;
 pub mod align;
 
 pub mod never;
+
+pub mod ctuple;
 //
 // Export Preludes:
 //
@@ -58,6 +60,7 @@ pub mod prelude {
     pub use crate::pod::{Pod,Mut};
     pub use crate::align::Align;
     pub use crate::never::Never;
+    pub use crate::ctuple::C;
 }
 
 pub mod public {