bionic test :StringTestState

// For every length we want to test, vary and change alignment
// of allocated memory, fill it with some values, calculate
// expected result and then run function and compare what we got.
// These tests contributed by Intel Corporation.
// TODO: make these tests more intention-revealing and less random.
template<class Character>
struct StringTestState {
  StringTestState(size_t MAX_LEN) : MAX_LEN(MAX_LEN) {
    int max_alignment = 64;

    // TODO: fix the tests to not sometimes use twice their specified "MAX_LEN".
    glob_ptr = reinterpret_cast<Character*>(valloc(2 * sizeof(Character) * MAX_LEN + max_alignment));
    glob_ptr1 = reinterpret_cast<Character*>(valloc(2 * sizeof(Character) * MAX_LEN + max_alignment));
    glob_ptr2 = reinterpret_cast<Character*>(valloc(2 * sizeof(Character) * MAX_LEN + max_alignment));

    InitLenArray();

    srandom(1234);
  }

  ~StringTestState() {
    free(glob_ptr);
    free(glob_ptr1);
    free(glob_ptr2);
  }

  void NewIteration() {
    int alignments[] = { 24, 32, 16, 48, 1, 2, 3, 0, 5, 11 };
    int usable_alignments = 10;
    int align1 = alignments[random() % (usable_alignments - 1)];
    int align2 = alignments[random() % (usable_alignments - 1)];

    ptr = glob_ptr + align1;
    ptr1 = glob_ptr1 + align1;
    ptr2 = glob_ptr2 + align2;
  }

  const size_t MAX_LEN;
  Character *ptr, *ptr1, *ptr2;
  size_t n;
  int len[ITER + 1];

 private:
  Character *glob_ptr, *glob_ptr1, *glob_ptr2;

  // Calculate input lengths and fill state.len with them.
  // Test small lengths with more density than big ones. Manually push
  // smallest (0) and biggest (MAX_LEN) lengths. Avoid repeats.
  // Return number of lengths to test.
  void InitLenArray() {
    n = 0;
    len[n++] = 0;
    for (size_t i = 1; i < ITER; ++i) {
      int l = (int) exp(log((double) MAX_LEN) * i / ITER);
      if (l != len[n - 1]) {
        len[n++] = l;
      }
    }
    len[n++] = MAX_LEN;
  }
};