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GCC Code Coverage Report

Directory:	cvmfs/		Exec	Total	Coverage
File:	cvmfs/prng.h	Lines:	15	15	100.0 %
Date:	2019-02-03 02:48:13	Branches:	1	2	50.0 %


/**
 * This file is part of the CernVM File System.
 *
 * A simple linear congruential pseudo number generator.  Thread-safe since
 * there is no global state like with random().
 */

#ifndef CVMFS_PRNG_H_
#define CVMFS_PRNG_H_

#include <stdint.h>
#include <sys/time.h>

#include <cassert>
#include <cstdlib>

#ifdef CVMFS_NAMESPACE_GUARD
namespace CVMFS_NAMESPACE_GUARD {
#endif

/**
 * Pseudo Random Number Generator.  See: TAoCP, volume 2
 */
class Prng {
 public:
  Prng() {
    state_ = 0;
  }

  void InitSeed(const uint64_t seed) {
    state_ = seed;
  }

  void InitLocaltime() {
    struct timeval tv_now;
    int retval = gettimeofday(&tv_now, NULL);
    assert(retval == 0);
    state_ = tv_now.tv_usec;
  }

  /**
   * Returns random number in [0..boundary-1]
   */
  uint32_t Next(const uint64_t boundary) {
    state_ = a*state_ + c;
    double scaled_val =
      static_cast<double>(state_) * static_cast<double>(boundary) /
      static_cast<double>(18446744073709551616.0);
    return (uint32_t)scaled_val % boundary;
  }

 private:
  // Magic numbers from MMIX
  // static const uint64_t m = 2^64;
  static const uint64_t a = 6364136223846793005LLU;
  static const uint64_t c = 1442695040888963407LLU;
  uint64_t state_;
};  // class Prng

#ifdef CVMFS_NAMESPACE_GUARD
}  // namespace CVMFS_NAMESPACE_GUARD
#endif

#endif  // CVMFS_PRNG_H_


Generated by: GCOVR (Version 4.1)

Line	Branch	Exec	Source
1			/**
2			* This file is part of the CernVM File System.
3			*
4			* A simple linear congruential pseudo number generator. Thread-safe since
5			* there is no global state like with random().
6			*/
7
8			#ifndef CVMFS_PRNG_H_
9			#define CVMFS_PRNG_H_
10
11			#include <stdint.h>
12			#include <sys/time.h>
13
14			#include <cassert>
15			#include <cstdlib>
16
17			#ifdef CVMFS_NAMESPACE_GUARD
18			namespace CVMFS_NAMESPACE_GUARD {
19			#endif
20
21			/**
22			* Pseudo Random Number Generator. See: TAoCP, volume 2
23			*/
24			class Prng {
25			public:
26		8004433	Prng() {
27		8004433	state_ = 0;
28		8004433	}
29
30		8002314	void InitSeed(const uint64_t seed) {
31		8002314	state_ = seed;
32		8002314	}
33
34		1913	void InitLocaltime() {
35			struct timeval tv_now;
36		1913	int retval = gettimeofday(&tv_now, NULL);
37	✗✓	1913	assert(retval == 0);
38		1913	state_ = tv_now.tv_usec;
39		1913	}
40
41			/**
42			* Returns random number in [0..boundary-1]
43			*/
44		6661429410	uint32_t Next(const uint64_t boundary) {
45		6661429410	state_ = a*state_ + c;
46			double scaled_val =
47			static_cast<double>(state_) * static_cast<double>(boundary) /
48		6661429410	static_cast<double>(18446744073709551616.0);
49		6661429410	return (uint32_t)scaled_val % boundary;
50			}
51
52			private:
53			// Magic numbers from MMIX
54			// static const uint64_t m = 2^64;
55			static const uint64_t a = 6364136223846793005LLU;
56			static const uint64_t c = 1442695040888963407LLU;
57			uint64_t state_;
58			}; // class Prng
59
60			#ifdef CVMFS_NAMESPACE_GUARD
61			} // namespace CVMFS_NAMESPACE_GUARD
62			#endif
63
64			#endif // CVMFS_PRNG_H_