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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef BASE_RAND_UTIL_H_
6 #define BASE_RAND_UTIL_H_
7 
8 #include <stddef.h>
9 #include <stdint.h>
10 
11 #include <string>
12 
13 #include "base/base_export.h"
14 #include "build/build_config.h"
15 
16 namespace base {
17 
18 // Returns a random number in range [0, UINT64_MAX]. Thread-safe.
19 BASE_EXPORT uint64_t RandUint64();
20 
21 // Returns a random number between min and max (inclusive). Thread-safe.
22 BASE_EXPORT int RandInt(int min, int max);
23 
24 // Returns a random number in range [0, range).  Thread-safe.
25 //
26 // Note that this can be used as an adapter for std::random_shuffle():
27 // Given a pre-populated |std::vector<int> myvector|, shuffle it as
28 //   std::random_shuffle(myvector.begin(), myvector.end(), base::RandGenerator);
29 BASE_EXPORT uint64_t RandGenerator(uint64_t range);
30 
31 // Returns a random double in range [0, 1). Thread-safe.
32 BASE_EXPORT double RandDouble();
33 
34 // Given input |bits|, convert with maximum precision to a double in
35 // the range [0, 1). Thread-safe.
36 BASE_EXPORT double BitsToOpenEndedUnitInterval(uint64_t bits);
37 
38 // Fills |output_length| bytes of |output| with random data.
39 //
40 // WARNING:
41 // Do not use for security-sensitive purposes.
42 // See crypto/ for cryptographically secure random number generation APIs.
43 BASE_EXPORT void RandBytes(void* output, size_t output_length);
44 
45 // Fills a string of length |length| with random data and returns it.
46 // |length| should be nonzero.
47 //
48 // Note that this is a variation of |RandBytes| with a different return type.
49 // The returned string is likely not ASCII/UTF-8. Use with care.
50 //
51 // WARNING:
52 // Do not use for security-sensitive purposes.
53 // See crypto/ for cryptographically secure random number generation APIs.
54 BASE_EXPORT std::string RandBytesAsString(size_t length);
55 
56 #if defined(OS_POSIX)
57 BASE_EXPORT int GetUrandomFD();
58 #endif
59 
60 }  // namespace base
61 
62 #endif  // BASE_RAND_UTIL_H_
63