C-API Cube info support (#30)

This PR adds support for obtaining the results of a cube evaluation in
the C-API. I've added the new `cube_info` function and `CCubeInfo`
types.

Cube evaluation is still using the simple 40/60 calculation, I'm
currently looking at improving this in another pr.

crates/logic/src/cube.rs

@@ -1,8 +1,10 @@
 use engine::probabilities::Probabilities;
+#[cfg(feature = "web")]
 use serde::Serialize;
+#[cfg(feature = "web")]
 use utoipa::ToSchema;
 
-#[derive(Serialize, ToSchema)]
+#[cfg_attr(feature = "web", derive(Serialize, ToSchema))]
 /// Information about proper cube decisions. Currently quick and dirty calculations.
 pub struct CubeInfo {
     /// `true` if the player `x` should double, `false` if no double yet or too good.
@@ -22,3 +24,12 @@ impl From<&Probabilities> for CubeInfo {
         Self { double, accept }
     }
 }
+
+impl CubeInfo {
+    pub fn double(&self) -> bool {
+        self.double
+    }
+    pub fn accept(&self) -> bool {
+        self.accept
+    }
+}

crates/logic/src/lib.rs

@@ -1,4 +1,3 @@
 pub mod bg_move;
-#[cfg(feature = "web")]
 pub mod cube;
 pub mod wildbg_api;

crates/logic/src/wildbg_api.rs

@@ -1,4 +1,5 @@
 use crate::bg_move::BgMove;
+use crate::cube::CubeInfo;
 use engine::composite::CompositeEvaluator;
 use engine::dice::Dice;
 use engine::evaluator::Evaluator;
@@ -37,6 +38,10 @@ impl<T: Evaluator> WildbgApi<T> {
         let new_position = self.evaluator.best_position(position, dice, value);
         BgMove::new(position, &new_position.sides_switched(), dice)
     }
+
+    pub fn cube_info(&self, position: &Position) -> CubeInfo {
+        CubeInfo::from(&self.evaluator.eval(position))
+    }
 }
 
 #[cfg(test)]

crates/wildbg-c/src/lib.rs

@@ -4,6 +4,7 @@ use engine::dice::Dice;
 use engine::position::Position;
 use engine::probabilities::Probabilities;
 use logic::bg_move::{BgMove, MoveDetail};
+use logic::cube::CubeInfo;
 use logic::wildbg_api::{WildbgApi, WildbgConfig};
 
 // When this file is changed, recreate the header file by executing this from the project's root:
@@ -148,6 +149,22 @@ impl From<&MoveDetail> for CMoveDetail {
     }
 }
 
+#[repr(C)]
+#[derive(Default)]
+pub struct CCubeInfo {
+    should_double: bool,
+    should_accept: bool,
+}
+
+impl From<&CubeInfo> for CCubeInfo {
+    fn from(value: &CubeInfo) -> Self {
+        Self {
+            should_double: value.double(),
+            should_accept: value.accept(),
+        }
+    }
+}
+
 type Error = &'static str;
 
 /// Returns the best move for the given position.
@@ -199,6 +216,21 @@ pub extern "C" fn probabilities(wildbg: &Wildbg, pips: &[c_int; 26]) -> CProbabi
     }
 }
 
+#[no_mangle]
+pub extern "C" fn cube_info(wildbg: &Wildbg, pips: &[c_int; 26]) -> CCubeInfo {
+    let pips = pips.map(|pip| pip as i8);
+    match Position::try_from(pips) {
+        Ok(position) => (&wildbg.api.cube_info(&position)).into(),
+        Err(error) => {
+            eprintln!("{}", error);
+            CCubeInfo {
+                should_double: false,
+                should_accept: false,
+            }
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
 

crates/wildbg-c/wildbg.h

@@ -70,6 +70,11 @@ typedef struct CProbabilities {
   float lose_bg;
 } CProbabilities;
 
+typedef struct CCubeInfo {
+  bool should_double;
+  bool should_accept;
+} CCubeInfo;
+
 /**
  * Loads the neural nets into memory and returns a pointer to the API.
  * Returns `NULL` if the neural nets cannot be found.
@@ -109,3 +114,5 @@ struct CMove best_move(const struct Wildbg *wildbg,
  */
 struct CProbabilities probabilities(const struct Wildbg *wildbg,
                                     const int (*pips)[26]);
+
+struct CCubeInfo cube_info(const struct Wildbg *wildbg, const int (*pips)[26]);