added hpx::partial_sort

Signed-off-by: Dikshant <dikshant.073@gmail.com>

hpx-sys/include/wrapper.h

@@ -180,3 +180,35 @@ inline void hpx_merge(const rust::Vec<int32_t>& src1,
         dest.push_back(item);
     }
 }
+
+inline void hpx_partial_sort(rust::Vec<int32_t>& src, size_t last) {
+    std::vector<int32_t> cpp_vec(src.begin(), src.end());
+
+    hpx::partial_sort(hpx::execution::par, 
+                      cpp_vec.begin(), 
+                      cpp_vec.begin() + last, 
+                      cpp_vec.end());
+
+    src.clear();
+    src.reserve(cpp_vec.size());
+    for (const auto& item : cpp_vec) {
+        src.push_back(item);
+    }
+}
+
+inline void hpx_partial_sort_comp(rust::Vec<int32_t>& src, size_t last, 
+                                  rust::Fn<bool(int32_t, int32_t)> comp) {
+    std::vector<int32_t> cpp_vec(src.begin(), src.end());
+
+    hpx::partial_sort(hpx::execution::par, 
+                      cpp_vec.begin(), 
+                      cpp_vec.begin() + last, 
+                      cpp_vec.end(),
+                      [&](int32_t a, int32_t b) { return comp(a, b); });
+
+    src.clear();
+    src.reserve(cpp_vec.size());
+    for (const auto& item : cpp_vec) {
+        src.push_back(item);
+    }
+}

hpx-sys/src/lib.rs

@@ -30,6 +30,8 @@ pub mod ffi {
         fn hpx_sort(src: &mut Vec<i32>);
         fn hpx_sort_comp(src: &mut Vec<i32>, comp: fn(i32, i32) -> bool);
         fn hpx_merge(src1: &Vec<i32>, src2: &Vec<i32>, dest: &mut Vec<i32>);
+        fn hpx_partial_sort(src: &mut Vec<i32>, last: usize);
+        fn hpx_partial_sort_comp(src: &mut Vec<i32>, last: usize, comp: fn(i32, i32) -> bool);
     }
 }
 
@@ -421,4 +423,64 @@ mod tests {
             assert_eq!(result, 0);
         }
     }
+
+    #[test]
+    #[serial]
+    fn test_hpx_partial_sort() {
+        let (argc, mut argv) = create_c_args(&["test_hpx_partial_sort"]);
+
+        let hpx_main = |_argc: i32, _argv: *mut *mut c_char| -> i32 {
+            let mut vec = vec![5, 2, 8, 1, 9, 3, 7, 6, 4];
+            let last = 4;
+            println!("Before partial sort: {:?}", vec);
+
+            ffi::hpx_partial_sort(&mut vec, last);
+            println!("After partial sort: {:?}", vec);
+
+            // If first -> last elements are sorted
+            assert!(vec[..last].windows(2).all(|w| w[0] <= w[1]));
+
+            // If ele of sorted part <=  ele of unsorted part
+            assert!(vec[..last]
+                .iter()
+                .all(|&x| vec[last..].iter().all(|&y| x <= y)));
+
+            ffi::finalize()
+        };
+
+        unsafe {
+            let result = ffi::init(hpx_main, argc, argv.as_mut_ptr());
+            assert_eq!(result, 0);
+        }
+    }
+
+    #[test]
+    #[serial]
+    fn test_hpx_partial_sort_comp() {
+        let (argc, mut argv) = create_c_args(&["test_hpx_partial_sort_comp"]);
+
+        let hpx_main = |_argc: i32, _argv: *mut *mut c_char| -> i32 {
+            let mut vec = vec![5, 2, 8, 1, 9, 3, 7, 6, 4];
+            let last = 4;
+            println!("Before partial sort: {:?}", vec);
+
+            ffi::hpx_partial_sort_comp(&mut vec, last, |a, b| b < a);
+            println!("After partial sort: {:?}", vec);
+
+            // If first -> last elements are sorted dec
+            assert!(vec[..last].windows(2).all(|w| w[0] >= w[1]));
+
+            // If ele of sorted part >= ele of unsorted part
+            assert!(vec[..last]
+                .iter()
+                .all(|&x| vec[last..].iter().all(|&y| x >= y)));
+
+            ffi::finalize()
+        };
+
+        unsafe {
+            let result = ffi::init(hpx_main, argc, argv.as_mut_ptr());
+            assert_eq!(result, 0);
+        }
+    }
 }