1 files changed, 89 insertions, 0 deletions
diff --git a/media/libeffects/loudness/common/core/math.h b/media/libeffects/loudness/common/core/math.h
new file mode 100644
index 0000000..3f302cc
--- /dev/null
+++ b/media/libeffects/loudness/common/core/math.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LE_FX_ENGINE_COMMON_CORE_MATH_H_
+#define LE_FX_ENGINE_COMMON_CORE_MATH_H_
+
+#include <math.h>
+#include <algorithm>
+using ::std::min;
+using ::std::max;
+using ::std::fill;
+using ::std::fill_n;using ::std::lower_bound;
+#include <cmath>
+#include <math.h>
+//using ::std::fpclassify;
+
+#include "common/core/os.h"
+#include "common/core/types.h"
+
+namespace le_fx {
+namespace math {
+
+// A fast approximation to log2(.)
+inline float fast_log2(float val) {
+  int* const exp_ptr = reinterpret_cast <int *> (&val);
+  int x = *exp_ptr;
+  const int log_2 = ((x >> 23) & 255) - 128;
+  x &= ~(255 << 23);
+  x += 127 << 23;
+  *exp_ptr = x;
+  val = ((-1.0f / 3) * val + 2) * val - 2.0f / 3;
+  return static_cast<float>(val + log_2);
+}
+
+// A fast approximation to log(.)
+inline float fast_log(float val) {
+  return fast_log2(val) *
+      0.693147180559945286226763982995180413126945495605468750f;
+}
+
+// An approximation of the exp(.) function using a 5-th order Taylor expansion.
+// It's pretty accurate between +-0.1 and accurate to 10e-3 between +-1
+template <typename T>
+inline T ExpApproximationViaTaylorExpansionOrder5(T x) {
+  const T x2 = x * x;
+  const T x3 = x2 * x;
+  const T x4 = x2 * x2;
+  const T x5 = x3 * x2;
+  return 1.0f + x + 0.5f * x2 +
+      0.16666666666666665741480812812369549646973609924316406250f * x3 +
+      0.0416666666666666643537020320309238741174340248107910156250f * x4 +
+      0.008333333333333333217685101601546193705871701240539550781250f * x5;
+}
+
+}  // namespace math
+}  // namespace le_fx
+
+// Math functions missing in Android NDK:
+#if defined(LE_FX_OS_ANDROID)
+
+namespace std {
+
+//
+// Round to the nearest integer: We need this implementation
+// since std::round is missing on android.
+//
+template <typename T>
+inline T round(const T &x) {
+  return static_cast<T>(std::floor(static_cast<double>(x) + 0.5));
+}
+
+}  // namespace std
+
+#endif  // LE_FX_OS_ANDROID
+
+#endif  // LE_FX_ENGINE_COMMON_CORE_MATH_H_