You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
79 lines
2.6 KiB
79 lines
2.6 KiB
4 months ago
|
// Copyright (c) 2012 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 BASE_RAND_UTIL_H_
|
||
|
|
#define BASE_RAND_UTIL_H_
|
||
|
|
|
||
|
|
#include <stddef.h>
|
||
|
|
#include <stdint.h>
|
||
|
|
|
||
|
|
#include <algorithm>
|
||
|
|
#include <string>
|
||
|
|
|
||
|
|
#include "base/base_export.h"
|
||
|
|
#include "build/build_config.h"
|
||
|
|
|
||
|
|
namespace base {
|
||
|
|
|
||
|
|
// Returns a random number in range [0, UINT64_MAX]. Thread-safe.
|
||
|
|
BASE_EXPORT uint64_t RandUint64();
|
||
|
|
|
||
|
|
// Returns a random number between min and max (inclusive). Thread-safe.
|
||
|
|
BASE_EXPORT int RandInt(int min, int max);
|
||
|
|
|
||
|
|
// Returns a random number in range [0, range). Thread-safe.
|
||
|
|
BASE_EXPORT uint64_t RandGenerator(uint64_t range);
|
||
|
|
|
||
|
|
// Returns a random double in range [0, 1). Thread-safe.
|
||
|
|
BASE_EXPORT double RandDouble();
|
||
|
|
|
||
|
|
// Given input |bits|, convert with maximum precision to a double in
|
||
|
|
// the range [0, 1). Thread-safe.
|
||
|
|
BASE_EXPORT double BitsToOpenEndedUnitInterval(uint64_t bits);
|
||
|
|
|
||
|
|
// Fills |output_length| bytes of |output| with random data. Thread-safe.
|
||
|
|
//
|
||
|
|
// Although implementations are required to use a cryptographically secure
|
||
|
|
// random number source, code outside of base/ that relies on this should use
|
||
|
|
// crypto::RandBytes instead to ensure the requirement is easily discoverable.
|
||
|
|
BASE_EXPORT void RandBytes(void* output, size_t output_length);
|
||
|
|
|
||
|
|
// Fills a string of length |length| with random data and returns it.
|
||
|
|
// |length| should be nonzero. Thread-safe.
|
||
|
|
//
|
||
|
|
// Note that this is a variation of |RandBytes| with a different return type.
|
||
|
|
// The returned string is likely not ASCII/UTF-8. Use with care.
|
||
|
|
//
|
||
|
|
// Although implementations are required to use a cryptographically secure
|
||
|
|
// random number source, code outside of base/ that relies on this should use
|
||
|
|
// crypto::RandBytes instead to ensure the requirement is easily discoverable.
|
||
|
|
BASE_EXPORT std::string RandBytesAsString(size_t length);
|
||
|
|
|
||
|
|
// An STL UniformRandomBitGenerator backed by RandUint64.
|
||
|
|
// TODO(tzik): Consider replacing this with a faster implementation.
|
||
|
|
class RandomBitGenerator {
|
||
|
|
public:
|
||
|
|
using result_type = uint64_t;
|
||
|
|
static constexpr result_type min() { return 0; }
|
||
|
|
static constexpr result_type max() { return UINT64_MAX; }
|
||
|
|
result_type operator()() const { return RandUint64(); }
|
||
|
|
|
||
|
|
RandomBitGenerator() = default;
|
||
|
|
~RandomBitGenerator() = default;
|
||
|
|
};
|
||
|
|
|
||
|
|
// Shuffles [first, last) randomly. Thread-safe.
|
||
|
|
template <typename Itr>
|
||
|
|
void RandomShuffle(Itr first, Itr last) {
|
||
|
|
std::shuffle(first, last, RandomBitGenerator());
|
||
|
|
}
|
||
|
|
|
||
|
|
#if defined(OS_POSIX)
|
||
|
|
BASE_EXPORT int GetUrandomFD();
|
||
|
|
#endif
|
||
|
|
|
||
|
|
} // namespace base
|
||
|
|
|
||
|
|
#endif // BASE_RAND_UTIL_H_
|