66 lines
2.3 KiB
C++
66 lines
2.3 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BUTIL_RAND_UTIL_H_
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#define BUTIL_RAND_UTIL_H_
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#include <string>
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#include "butil/base_export.h"
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#include "butil/basictypes.h"
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namespace butil {
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// --------------------------------------------------------------------------
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// NOTE(gejun): Functions in this header read from /dev/urandom in posix
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// systems and are not proper for performance critical situations.
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// For fast random numbers, check fast_rand.h
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// --------------------------------------------------------------------------
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// Returns a random number in range [0, kuint64max]. Thread-safe.
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BUTIL_EXPORT uint64_t RandUint64();
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// Returns a random number between min and max (inclusive). Thread-safe.
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BUTIL_EXPORT int RandInt(int min, int max);
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// Returns a random number in range [0, range). Thread-safe.
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//
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// Note that this can be used as an adapter for std::random_shuffle():
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// Given a pre-populated |std::vector<int> myvector|, shuffle it as
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// std::random_shuffle(myvector.begin(), myvector.end(), butil::RandGenerator);
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BUTIL_EXPORT uint64_t RandGenerator(uint64_t range);
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// Returns a random double in range [0, 1). Thread-safe.
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BUTIL_EXPORT double RandDouble();
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// Given input |bits|, convert with maximum precision to a double in
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// the range [0, 1). Thread-safe.
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BUTIL_EXPORT double BitsToOpenEndedUnitInterval(uint64_t bits);
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// Fills |output_length| bytes of |output| with random data.
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//
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// WARNING:
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// Do not use for security-sensitive purposes.
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// See crypto/ for cryptographically secure random number generation APIs.
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BUTIL_EXPORT void RandBytes(void* output, size_t output_length);
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// Fills a string of length |length| with random data and returns it.
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// |length| should be nonzero.
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//
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// Note that this is a variation of |RandBytes| with a different return type.
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// The returned string is likely not ASCII/UTF-8. Use with care.
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//
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// WARNING:
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// Do not use for security-sensitive purposes.
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// See crypto/ for cryptographically secure random number generation APIs.
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BUTIL_EXPORT std::string RandBytesAsString(size_t length);
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#if defined(OS_POSIX)
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BUTIL_EXPORT int GetUrandomFD();
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#endif
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} // namespace butil
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#endif // BUTIL_RAND_UTIL_H_
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