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+/*
+ * Copyright (c) 2016, Alliance for Open Media. All rights reserved
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+
+#ifndef AOM_TEST_ACM_RANDOM_H_
+#define AOM_TEST_ACM_RANDOM_H_
+
+#include "third_party/googletest/src/googletest/include/gtest/gtest.h"
+
+#include "aom/aom_integer.h"
+
+namespace libaom_test {
+
+class ACMRandom {
+ public:
+  ACMRandom() : random_(DeterministicSeed()) {}
+
+  explicit ACMRandom(int seed) : random_(seed) {}
+
+  void Reset(int seed) { random_.Reseed(seed); }
+
+  // Generates a random 31-bit unsigned integer from [0, 2^31).
+  uint32_t Rand31() {
+    return random_.Generate(testing::internal::Random::kMaxRange);
+  }
+
+  uint16_t Rand16() {
+    const uint32_t value =
+        random_.Generate(testing::internal::Random::kMaxRange);
+    // There's a bit more entropy in the upper bits of this implementation.
+    return (value >> 15) & 0xffff;
+  }
+
+  int16_t Rand16Signed() { return static_cast<int16_t>(Rand16()); }
+
+  int16_t Rand15() {
+    const uint32_t value =
+        random_.Generate(testing::internal::Random::kMaxRange);
+    // There's a bit more entropy in the upper bits of this implementation.
+    return (value >> 16) & 0x7fff;
+  }
+
+  int16_t Rand15Signed() {
+    // Use 15 bits: values between 16383 (0x3FFF) and -16384 (0xC000).
+    return static_cast<int16_t>(Rand15()) - (1 << 14);
+  }
+
+  uint16_t Rand12() {
+    const uint32_t value =
+        random_.Generate(testing::internal::Random::kMaxRange);
+    // There's a bit more entropy in the upper bits of this implementation.
+    return (value >> 19) & 0xfff;
+  }
+
+  uint8_t Rand8() {
+    const uint32_t value =
+        random_.Generate(testing::internal::Random::kMaxRange);
+    // There's a bit more entropy in the upper bits of this implementation.
+    return (value >> 23) & 0xff;
+  }
+
+  uint8_t Rand8Extremes() {
+    // Returns a random value near 0 or near 255, to better exercise
+    // saturation behavior.
+    const uint8_t r = Rand8();
+    return static_cast<uint8_t>((r < 128) ? r << 4 : r >> 4);
+  }
+
+  int PseudoUniform(int range) { return random_.Generate(range); }
+
+  int operator()(int n) { return PseudoUniform(n); }
+
+  static int DeterministicSeed() { return 0xbaba; }
+
+ private:
+  testing::internal::Random random_;
+};
+
+}  // namespace libaom_test
+
+#endif  // AOM_TEST_ACM_RANDOM_H_