Bind ValidateCpModel and SolutionIsFeasible from cp_model_checker.h

Fixes #22

src/builder.rs

@@ -715,6 +715,25 @@ impl CpModelBuilder {
         ffi::cp_model_stats(self.proto())
     }
 
+    /// Verifies that the given model satisfies all the properties
+    /// described in the proto comments. Returns an empty string if it is
+    /// the case, otherwise fails at the first error and returns a
+    /// human-readable description of the issue.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use cp_sat::builder::CpModelBuilder;
+    /// # use cp_sat::proto::CpSolverStatus;
+    /// let mut model = CpModelBuilder::default();
+    /// let x = model.new_int_var([(0, -1)]);
+    /// model.maximize(x);
+    /// assert!(!model.validate_cp_model().is_empty());
+    /// ```
+    pub fn validate_cp_model(&self) -> String {
+        ffi::validate_cp_model(self.proto())
+    }
+
     /// Solves the model, and returns the corresponding [proto::CpSolverResponse].
     ///
     /// # Example

src/cp_sat_wrapper.cpp

@@ -1,6 +1,7 @@
 #include <iostream>
 
 #include <ortools/sat/cp_model.h>
+#include <ortools/sat/cp_model_checker.h>
 
 namespace sat = operations_research::sat;
 
@@ -73,3 +74,33 @@ cp_sat_wrapper_cp_solver_response_stats(
     const std::string stats = sat::CpSolverResponseStats(response, has_objective);
     return strdup(stats.c_str());
 }
+
+extern "C" char*
+cp_sat_wrapper_validate_cp_model(unsigned char* model_buf, size_t model_size) {
+    sat::CpModelProto model;
+    const bool res = model.ParseFromArray(model_buf, model_size);
+    assert(res);
+
+    const std::string stats = sat::ValidateCpModel(model);
+    return strdup(stats.c_str());
+}
+
+extern "C" bool
+cp_sat_wrapper_solution_is_feasible(
+    unsigned char* model_buf,
+    size_t model_size,
+    const int64_t* solution_buf,
+    size_t solution_size)
+{
+    sat::CpModelProto model;
+    const bool res = model.ParseFromArray(model_buf, model_size);
+    assert(res);
+
+    std::vector<int64_t> variable_values;
+    variable_values.reserve(solution_size);
+    for (size_t i = 0; i < solution_size; ++i) {
+        variable_values.push_back(solution_buf[i]);
+    }
+
+    return sat::SolutionIsFeasible(model, variable_values);
+}

src/ffi.rs

@@ -22,6 +22,13 @@ extern "C" {
         response_size: usize,
         has_objective: bool,
     ) -> *mut c_char;
+    fn cp_sat_wrapper_validate_cp_model(model_buf: *const u8, model_size: usize) -> *mut c_char;
+    fn cp_sat_wrapper_solution_is_feasible(
+        model_buf: *const u8,
+        model_size: usize,
+        solution_buf: *const i64,
+        solution_size: usize,
+    ) -> bool;
 }
 
 /// Solves the given [CpModelProto][crate::proto::CpModelProto] and
@@ -101,3 +108,51 @@ pub fn cp_solver_response_stats(response: &proto::CpSolverResponse, has_objectiv
     unsafe { libc::free(char_ptr as _) };
     res
 }
+
+/// Verifies that the given model satisfies all the properties
+/// described in the proto comments. Returns an empty string if it is
+/// the case, otherwise fails at the first error and returns a
+/// human-readable description of the issue.
+pub fn validate_cp_model(model: &proto::CpModelProto) -> String {
+    let mut model_buf = Vec::default();
+    model.encode(&mut model_buf).unwrap();
+    let char_ptr = unsafe { cp_sat_wrapper_validate_cp_model(model_buf.as_ptr(), model_buf.len()) };
+    let res = unsafe { CStr::from_ptr(char_ptr) }
+        .to_str()
+        .unwrap()
+        .to_owned();
+    unsafe { libc::free(char_ptr as _) };
+    res
+}
+
+/// Verifies that the given variable assignment is a feasible solution
+/// of the given model. The values vector should be in one to one
+/// correspondence with the model.variables() list of variables.
+///
+/// # Example
+///
+/// ```
+/// # use cp_sat::builder::CpModelBuilder;
+/// # use cp_sat::proto::CpSolverStatus;
+/// # use cp_sat::ffi::solution_is_feasible;
+/// let mut model = CpModelBuilder::default();
+/// let x = model.new_bool_var();
+/// let y = model.new_bool_var();
+/// model.add_and([x, y]);
+/// assert!(solution_is_feasible(model.proto(), &[1, 1]));
+/// assert!(!solution_is_feasible(model.proto(), &[1, 0]));
+/// assert!(!solution_is_feasible(model.proto(), &[0, 1]));
+/// assert!(!solution_is_feasible(model.proto(), &[0, 0]));
+/// ```
+pub fn solution_is_feasible(model: &proto::CpModelProto, solution: &[i64]) -> bool {
+    let mut model_buf = Vec::default();
+    model.encode(&mut model_buf).unwrap();
+    unsafe {
+        cp_sat_wrapper_solution_is_feasible(
+            model_buf.as_ptr(),
+            model_buf.len(),
+            solution.as_ptr(),
+            solution.len(),
+        )
+    }
+}

src/lib.rs

@@ -57,3 +57,5 @@ pub mod proto {
 
 /// Interface with the CP SAT functions.
 pub mod ffi;
+
+pub use prost;