+
+// align_ptr_up() : get the first aligned element of an array.
+// ptr must point to an array of size at least `sizeof(T) * N + alignment` bytes,
+// where N is the number of elements in the array.
+template <uintptr_t Alignment, typename T>
+T* align_ptr_up(T* ptr)
+{
+ static_assert(alignof(T) < Alignment);
+
+ const uintptr_t ptrint = reinterpret_cast<uintptr_t>(reinterpret_cast<char*>(ptr));
+ return reinterpret_cast<T*>(reinterpret_cast<char*>((ptrint + (Alignment - 1)) / Alignment * Alignment));
+}
+
+
+// IsLittleEndian : true if and only if the binary is compiled on a little endian machine
+static inline const union { uint32_t i; char c[4]; } Le = { 0x01020304 };
+static inline const bool IsLittleEndian = (Le.c[0] == 4);
+
+
+// RunningAverage : a class to calculate a running average of a series of values.
+// For efficiency, all computations are done with integers.
+class RunningAverage {
+ public:
+
+ // Constructor
+ RunningAverage() {}
+
+ // Reset the running average to rational value p / q
+ void set(int64_t p, int64_t q)
+ { average = p * PERIOD * RESOLUTION / q; }
+
+ // Update average with value v
+ void update(int64_t v)
+ { average = RESOLUTION * v + (PERIOD - 1) * average / PERIOD; }
+
+ // Test if average is strictly greater than rational a / b
+ bool is_greater(int64_t a, int64_t b)
+ { return b * average > a * PERIOD * RESOLUTION ; }
+
+ private :
+ static constexpr int64_t PERIOD = 4096;
+ static constexpr int64_t RESOLUTION = 1024;
+ int64_t average;