Multi reader/writer cache/buffer

media/blink/test_random.h

+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_BLINK_TEST_RANDOM_H_
+#define MEDIA_BLINK_TEST_RANDOM_H_
+
+// Vastly simplified ACM random class meant to only be used for testing.
+
+namespace media {
+
+class TestRandom {
+ public:
+  explicit TestRandom(uint32 seed) {
+    seed_ = seed & 0x7fffffff;  // make this a non-negative number
+    if (seed_ == 0 || seed_ == M) {
+      seed_ = 1;
+    }
+  }
+
+  int32 Rand() {
+    static const uint64 A = 16807;  // bits 14, 8, 7, 5, 2, 1, 0
+    seed_ = static_cast<int32>((seed_ * A) % M);
+    CHECK_GT(seed_, 0);
+    return seed_;
+  }
+
+ private:
+  static const uint64 M = 2147483647L;  // 2^32-1
+  int32 seed_;
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BLINK_TEST_RANDOM_H_