Vutils

include/Vutils.h

@@ -218,8 +218,12 @@ bool vuapi use_std_io_console_window();
 bool vuapi is_flag_on(ulongptr flags, ulongptr flag);
 intptr vuapi gcd(ulongptr count, ...); // UCLN
 intptr vuapi lcm(ulongptr count, ...); // BCNN
-float vuapi fast_sqrtf(const float number); // Estimates the square root of a 32-bit floating-point number (from Quake III Arena)
 void vuapi hex_dump(const void* data, int size);
+float vuapi fast_sqrtf(const float number); // Estimates the square root of a 32-bit floating-point number (from Quake III Arena)
+void divide_items_into_pieces(const size_t num_items, const size_t num_pieces,
+  std::function<void(size_t idx, size_t f, size_t end, size_t num)> fn);
+size_t divide_items_into_num_items_per_piece(const size_t num_items, const size_t num_items_per_piece,
+  std::function<void(size_t idx, size_t f, size_t end, size_t num)> fn);
 
 #include "template/math.tpl"
 

src/details/math.cpp

@@ -128,4 +128,90 @@ float vuapi fast_sqrtf(const float number)
   return 1.F / q_rsqrt(number);
 }
 
+/**
+ * Divides a set of items into a specified number of pieces.
+ * @param[in] num_items  The number of items.
+ * @param[in] num_pieces The number of pieces.
+ * @param[in] fn The function that apply to each piece.
+ *    idx The piece index.
+ *    beg The index of the begin item in piece.
+ *    end The index of the end item in piece.
+ *    num The number of items in piece.
+ * Eg. In these cases, the number of items of each piece as the following:
+ *  (4, 1) => (4)
+ *  (4, 2) => (2, 2)
+ *  (4, 3) => (1, 1, 2)
+ *  (4, 4) => (1, 1, 1, 1)
+ *  (4, 5) => (1, 1, 1, 1, 0)
+ */
+void divide_items_into_pieces(const size_t num_items, const size_t num_pieces,
+  std::function<void(size_t idx, size_t f, size_t end, size_t num)> fn)
+{
+  if (fn == nullptr)
+  {
+    return;
+  }
+
+  size_t num_items_per_piece = std::max(1, int(num_items / float(num_pieces) + 0.5F));
+
+  for (size_t idx = 0; idx < num_pieces; ++idx)
+  {
+    size_t beg = idx * num_items_per_piece;
+    size_t end = idx == num_pieces - 1 ? num_items : (idx + 1) * num_items_per_piece;
+    size_t num = end - beg;
+
+    beg = idx < num_items ? beg : -1;
+    end = idx < num_items ? end - 1 : -1;
+    num = idx < num_items ? num : 0;
+
+    fn(idx, beg, end, num);
+  }
+}
+
+/**
+ * Divides a set of items into a specified number of items per piece.
+ * @param[in] num_items  The number of items.
+ * @param[in] num_pieces The number of item per piece.
+ * @param[in] fn The function that apply to each piece.
+ *    idx The piece index.
+ *    beg The index of the begin item in piece.
+ *    end The index of the end item in piece.
+ *    num The number of items in piece.
+ * @return The number of pieces.
+ * Eg. The number of items of each piece as the following.
+ *  (4, 1) => (1, 1, 1, 1)
+ *  (4, 2) => (2, 2)
+ *  (4, 3) => (3, 1, 1)
+ *  (4, 4) => (4)
+ *  (4, 5) => (4)
+ */
+size_t divide_items_into_num_items_per_piece(const size_t num_items, const size_t num_items_per_piece,
+  std::function<void(size_t idx, size_t f, size_t end, size_t num)> fn)
+{
+  if (fn == nullptr)
+  {
+    return 0;
+  }
+
+  size_t result = 0;
+
+  std::vector<size_t> piece;
+
+  for (size_t j = 1; j <= num_items; j++)
+  {
+    size_t i = j - 1;
+
+    piece.push_back(i);
+
+    if (j % num_items_per_piece == 0 || i == num_items - 1)
+    {
+      fn(result, piece.front(), piece.back(), piece.size());
+      piece.clear();
+      result += 1;
+    }
+  }
+
+  return result;
+}
+
 } // namespace vu