summaryrefslogtreecommitdiffstats
path: root/src/rocksdb/util/random.cc
blob: c94c28dfb2b51cbbd3bdce53654e38277a9745c4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
//  This source code is licensed under both the GPLv2 (found in the
//  COPYING file in the root directory) and Apache 2.0 License
//  (found in the LICENSE.Apache file in the root directory).
//

#include "util/random.h"

#include <stdint.h>
#include <string.h>

#include <thread>
#include <utility>

#include "port/likely.h"
#include "util/thread_local.h"

#define STORAGE_DECL static thread_local

namespace ROCKSDB_NAMESPACE {

Random* Random::GetTLSInstance() {
  STORAGE_DECL Random* tls_instance;
  STORAGE_DECL std::aligned_storage<sizeof(Random)>::type tls_instance_bytes;

  auto rv = tls_instance;
  if (UNLIKELY(rv == nullptr)) {
    size_t seed = std::hash<std::thread::id>()(std::this_thread::get_id());
    rv = new (&tls_instance_bytes) Random((uint32_t)seed);
    tls_instance = rv;
  }
  return rv;
}

std::string Random::HumanReadableString(int len) {
  std::string ret;
  ret.resize(len);
  for (int i = 0; i < len; ++i) {
    ret[i] = static_cast<char>('a' + Uniform(26));
  }
  return ret;
}

std::string Random::RandomString(int len) {
  std::string ret;
  ret.resize(len);
  for (int i = 0; i < len; i++) {
    ret[i] = static_cast<char>(' ' + Uniform(95));  // ' ' .. '~'
  }
  return ret;
}

std::string Random::RandomBinaryString(int len) {
  std::string ret;
  ret.resize(len);
  for (int i = 0; i < len; i++) {
    ret[i] = static_cast<char>(Uniform(CHAR_MAX));
  }
  return ret;
}

}  // namespace ROCKSDB_NAMESPACE