custom_stats.h

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/***************************************************************************
 * include/stxxl/bits/common/custom_stats.h
 *
 * Part of the STXXL. See http://stxxl.sourceforge.net
 *
 * Copyright (C) 2014 Thomas Keh <[email protected]>
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE_1_0.txt or copy at
 * http://www.boost.org/LICENSE_1_0.txt)
 **************************************************************************/

#ifndef STXXL_COMMON_CUSTOM_STATS_HEADER
#define STXXL_COMMON_CUSTOM_STATS_HEADER

#include <string>
#include <utility>
#include <algorithm>
#include <stxxl/bits/common/timer.h>
#include <stxxl/bits/common/utils.h>

STXXL_BEGIN_NAMESPACE

/*!
 * This class provides a statistical counter that can easily be deactivated
 * using a typedef to dummy_custom_stats_counter. It's basically a wrapper for
 * a unsigned long long value.
 *
 * \see dummy_custom_stats_counter
 */
template <typename ValueType>
class custom_stats_counter
{
public:
 //! The counter's value type
 typedef ValueType value_type;

protected:
 //! The counter's value
 value_type m_value;

public:
 //! The constructor. Initializes the counter to 0.
 custom_stats_counter()
 : m_value(0)
 { }

 //! Increases the counter by right.
 //! \param right The corresponding integer value
 custom_stats_counter& operator += (const value_type& right)
 {
 m_value += right;
 return *this;
 }
 //! Increases the counter by 1 (prefix).
 custom_stats_counter& operator ++ ()
 {
 ++m_value;
 return *this;
 }
 //! Increases the counter by 1 (postfix).
 custom_stats_counter operator ++ (int)
 {
 custom_stats_counter copy = *this;
 ++m_value;
 return copy;
 }
 //! Assignment operator
 //! \param other The corresponding integer value
 custom_stats_counter& operator = (const value_type& other)
 {
 m_value = other;
 return *this;
 }
 /*!
 * Set the counter to other if other is larger than the current counter
 * value.
 *
 * \param other The corresponding integer value
 */
 void set_max(const value_type& other)
 {
 m_value = std::max(m_value, other);
 }
 /*!
 * Return the counter value interpreted as a memory amount in IEC units as
 * a string. For that purpose the counter value is multiplied with the
 * byte_per_element argument.
 *
 * \param byte_per_element The memory amount per "counter element".
 */
 std::string as_memory_amount(const value_type& byte_per_element) const
 {
 return format_IEC_size(m_value * byte_per_element) + "B";
 }
 /*!
 * Cast to counter_type: Returns the counter's value as a regular integer
 * value. This can be used as a getter as well as for printing with
 * std::out.
 */
 operator value_type () const
 {
 return m_value;
 }
};

/*!
 * Dummy class for custom_stats_counter. The methods do nothing. The compiler
 * should optimize out the code.
 *
 * \see custom_stats_counter
 */
template <typename ValueType>
class dummy_custom_stats_counter
{
public:
 typedef ValueType value_type;

public:
 dummy_custom_stats_counter() { }
 dummy_custom_stats_counter& operator += (const value_type&)
 {
 return *this;
 }
 dummy_custom_stats_counter& operator ++ ()
 {
 return *this;
 }
 dummy_custom_stats_counter& operator ++ (int)
 {
 return *this;
 }
 dummy_custom_stats_counter& operator = (const value_type&)
 {
 return *this;
 }
 void set_max(value_type) { }
 std::string as_memory_amount(const value_type&) const
 {
 return "";
 }
 operator value_type () const
 {
 return value_type();
 }
};

STXXL_END_NAMESPACE

#endif // !STXXL_COMMON_CUSTOM_STATS_HEADER