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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); }
+
+ uint32_t Rand31(void) {
+ return random_.Generate(testing::internal::Random::kMaxRange);
+ }
+
+ uint16_t Rand16(void) {
+ const uint32_t value =
+ random_.Generate(testing::internal::Random::kMaxRange);
+ return (value >> 15) & 0xffff;
+ }
+
+ int16_t Rand15Signed(void) {
+ const uint32_t value =
+ random_.Generate(testing::internal::Random::kMaxRange);
+ return (value >> 17) & 0xffff;
+ }
+
+ uint16_t Rand12(void) {
+ 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;
+ }
+
+ int16_t Rand9Signed(void) {
+ // Use 9 bits: values between 255 (0x0FF) and -256 (0x100).
+ const uint32_t value = random_.Generate(512);
+ return static_cast<int16_t>(value) - 256;
+ }
+
+ uint8_t Rand8(void) {
+ 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(void) {
+ // Returns a random value near 0 or near 255, to better exercise
+ // saturation behavior.
+ const uint8_t r = Rand8();
+ return r < 128 ? r << 4 : r >> 4;
+ }
+
+ int PseudoUniform(int range) { return random_.Generate(range); }
+
+ int operator()(int n) { return PseudoUniform(n); }
+
+ static int DeterministicSeed(void) { return 0xbaba; }
+
+ private:
+ testing::internal::Random random_;
+};
+
+} // namespace libaom_test
+
+#endif // AOM_TEST_ACM_RANDOM_H_