base/rand_util.h

   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 <string>
   9
  10 #include "base/base_export.h"
  11 #include "base/basictypes.h"
  12
  13 namespace base {
  14
  15 // Returns a random number in range [0, kuint64max]. Thread-safe.
  16 BASE_EXPORT uint64 RandUint64();
  17
  18 // Returns a random number between min and max (inclusive). Thread-safe.
  19 BASE_EXPORT int RandInt(int min, int max);
  20
  21 // Returns a random number in range [0, range).  Thread-safe.
  22 //
  23 // Note that this can be used as an adapter for std::random_shuffle():
  24 // Given a pre-populated |std::vector<int> myvector|, shuffle it as
  25 //   std::random_shuffle(myvector.begin(), myvector.end(), base::RandGenerator);
  26 BASE_EXPORT uint64 RandGenerator(uint64 range);
  27
  28 // Returns a random double in range [0, 1). Thread-safe.
  29 BASE_EXPORT double RandDouble();
  30
  31 // Given input |bits|, convert with maximum precision to a double in
  32 // the range [0, 1). Thread-safe.
  33 BASE_EXPORT double BitsToOpenEndedUnitInterval(uint64 bits);
  34
  35 // Fills |output_length| bytes of |output| with random data.
  36 //
  37 // WARNING:
  38 // Do not use for security-sensitive purposes.
  39 // See crypto/ for cryptographically secure random number generation APIs.
  40 BASE_EXPORT void RandBytes(void* output, size_t output_length);
  41
  42 // Fills a string of length |length| with random data and returns it.
  43 // |length| should be nonzero.
  44 //
  45 // Note that this is a variation of |RandBytes| with a different return type.
  46 // The returned string is likely not ASCII/UTF-8. Use with care.
  47 //
  48 // WARNING:
  49 // Do not use for security-sensitive purposes.
  50 // See crypto/ for cryptographically secure random number generation APIs.
  51 BASE_EXPORT std::string RandBytesAsString(size_t length);
  52
  53 #if defined(OS_POSIX)
  54 BASE_EXPORT int GetUrandomFD();
  55 #endif
  56
  57 }  // namespace base
  58
  59 #endif  // BASE_RAND_UTIL_H_