testutil.cc raw

   1  // Copyright (c) 2011 The LevelDB 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. See the AUTHORS file for names of contributors.
   4  
   5  #include "util/testutil.h"
   6  
   7  #include "util/random.h"
   8  
   9  namespace leveldb {
  10  namespace test {
  11  
  12  Slice RandomString(Random* rnd, int len, std::string* dst) {
  13    dst->resize(len);
  14    for (int i = 0; i < len; i++) {
  15      (*dst)[i] = static_cast<char>(' ' + rnd->Uniform(95));  // ' ' .. '~'
  16    }
  17    return Slice(*dst);
  18  }
  19  
  20  std::string RandomKey(Random* rnd, int len) {
  21    // Make sure to generate a wide variety of characters so we
  22    // test the boundary conditions for short-key optimizations.
  23    static const char kTestChars[] = {'\0', '\1', 'a',    'b',    'c',
  24                                      'd',  'e',  '\xfd', '\xfe', '\xff'};
  25    std::string result;
  26    for (int i = 0; i < len; i++) {
  27      result += kTestChars[rnd->Uniform(sizeof(kTestChars))];
  28    }
  29    return result;
  30  }
  31  
  32  Slice CompressibleString(Random* rnd, double compressed_fraction, size_t len,
  33                           std::string* dst) {
  34    int raw = static_cast<int>(len * compressed_fraction);
  35    if (raw < 1) raw = 1;
  36    std::string raw_data;
  37    RandomString(rnd, raw, &raw_data);
  38  
  39    // Duplicate the random data until we have filled "len" bytes
  40    dst->clear();
  41    while (dst->size() < len) {
  42      dst->append(raw_data);
  43    }
  44    dst->resize(len);
  45    return Slice(*dst);
  46  }
  47  
  48  }  // namespace test
  49  }  // namespace leveldb
  50