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https://github.com/dart-lang/sdk
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1f7384beb8
Fixes https://github.com/dart-lang/sdk/issues/53081 TEST=Service tests Change-Id: I0aaf3843c3a186336f5b2a8ee1e9356dd19251b8 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/317460 Reviewed-by: Derek Xu <derekx@google.com> Commit-Queue: Ben Konyi <bkonyi@google.com>
62 lines
1.5 KiB
C++
62 lines
1.5 KiB
C++
// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#ifndef RUNTIME_VM_RANDOM_H_
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#define RUNTIME_VM_RANDOM_H_
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#include <atomic>
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#include "vm/allocation.h"
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#include "vm/flags.h"
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#include "vm/globals.h"
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namespace dart {
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DECLARE_FLAG(uint64_t, random_seed);
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class Random {
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public:
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Random();
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// Seed must be non-zero.
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explicit Random(uint64_t seed);
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~Random();
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uint32_t NextUInt32();
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uint64_t NextUInt64() {
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return (static_cast<uint64_t>(NextUInt32()) << 32) |
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static_cast<uint64_t>(NextUInt32());
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}
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// Returns a random number that's a valid JS integer.
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//
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// All IDs that can be returned over the service protocol should be
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// representable as JS integers and should be generated using this method.
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//
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// See https://github.com/dart-lang/sdk/issues/53081.
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uint64_t NextJSInt() {
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// Number.MAX_SAFE_INTEGER (2 ^ 53 - 1)
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const uint64_t kMaxJsInt = 0x1FFFFFFFFFFFFF;
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return NextUInt64() & kMaxJsInt;
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}
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static uint64_t GlobalNextUInt64();
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static void Init();
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static void Cleanup();
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// Generates a uniform random variable in the range [0,1].
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double NextDouble();
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private:
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uint64_t NextState();
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void Initialize(uint64_t seed);
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std::atomic<uint64_t> _state;
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DISALLOW_COPY_AND_ASSIGN(Random);
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};
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} // namespace dart
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#endif // RUNTIME_VM_RANDOM_H_
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