Add div_pos_int_ceil function

Author: Dobiasd

include/fplus/numeric.hpp

@@ -833,6 +833,14 @@ std::function<X(X)> divide_by(const X& x)
     };
 }
 
+// API search type: div_pos_int_ceil : (a, a) -> a
+// Integer division, but rounding up instead of down.
+// div_pos_int_ceil(5, 3) == 2
+template<typename X>
+static auto div_pos_int_ceil(X numerator, X denominator) {
+    return numerator / denominator + (numerator % denominator != 0);
+}
+
 // API search type: histogram_using_intervals : ([(a, a)], [a]) -> [((a, a), Int)]
 // fwd bind count: 1
 // Generate a histogram of a sequence with given bins.

include/fplus/split.hpp

@@ -500,7 +500,7 @@ template <typename ContainerIn,
     typename ContainerOut = std::vector<ContainerIn>>
 ContainerOut split_evenly(std::size_t n, const ContainerIn& xs)
 {
-    const std::size_t every_n = size_of_cont(xs) / n;
+    const std::size_t every_n = div_pos_int_ceil(size_of_cont(xs), n);
     return split_at_idxs<
         std::vector<std::size_t>,
         ContainerIn,

include_all_in_one/include/fplus/fplus.hpp

@@ -8351,6 +8351,14 @@ std::function<X(X)> divide_by(const X& x)
     };
 }
 
+// API search type: div_pos_int_ceil : (a, a) -> a
+// Integer division, but rounding up instead of down.
+// div_pos_int_ceil(5, 3) == 2
+template<typename X>
+static auto div_pos_int_ceil(X numerator, X denominator) {
+    return numerator / denominator + (numerator % denominator != 0);
+}
+
 // API search type: histogram_using_intervals : ([(a, a)], [a]) -> [((a, a), Int)]
 // fwd bind count: 1
 // Generate a histogram of a sequence with given bins.
@@ -10770,7 +10778,7 @@ template <typename ContainerIn,
     typename ContainerOut = std::vector<ContainerIn>>
 ContainerOut split_evenly(std::size_t n, const ContainerIn& xs)
 {
-    const std::size_t every_n = size_of_cont(xs) / n;
+    const std::size_t every_n = div_pos_int_ceil(size_of_cont(xs), n);
     return split_at_idxs<
         std::vector<std::size_t>,
         ContainerIn,

test/numeric_test.cpp

@@ -286,6 +286,12 @@ TEST_CASE("numeric_test - ceil_to_int_mult")
     REQUIRE_EQ(ceil_to_int_mult(1, 1), 1);
 }
 
+TEST_CASE("numeric_test - div_pos_int_ceil")
+{
+    using namespace fplus;
+    REQUIRE_EQ(div_pos_int_ceil(5, 3), 2);
+}
+
 TEST_CASE("numeric_test - reference_interval")
 {
     using namespace fplus;