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Added cyclic value class

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jwellbelove 2014-10-31 15:54:27 +00:00
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///\file
/******************************************************************************
The MIT License(MIT)
Embedded Template Library.
Copyright(c) 2014 jwellbelove
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files(the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions :
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
******************************************************************************/
#ifndef __etl_cyclic_value__
#define __etl_cyclic_value__
#include <cstddef>
///\defgroup cyclic_value cyclic_value
/// Provides a value that cycles between two limits.
/// \ingroup utilities
#include <algorithm>
#include "static_assert.h"
#include "exception.h"
namespace etl
{
#ifdef ETL_USE_EXCEPTIONS
//***************************************************************************
///\ingroup cyclic_value
/// The base class for cyclic_value exceptions.
//***************************************************************************
class cyclic_value_exception : public exception
{
public:
cyclic_value_exception(const char* what)
: exception(what)
{
}
};
//***************************************************************************
///\ingroup cyclic_value
/// The illegal range exception.
//***************************************************************************
class cyclic_value_illegal_range_exception : public cyclic_value_exception
{
public:
cyclic_value_illegal_range_exception()
: cyclic_value_exception("cyclic_value illegal range")
{
}
};
#endif
//***************************************************************************
/// Provides a value that cycles between two limits.
/// Supports incrementing and decrementing.
///\tparam T The type of the variable.
///\tparam FIRST The first value of the range.
///\tparam LAST The last value of the range.
///\tparam STEP The amount to increment or decrement. Default = 1.
///\note LAST - FIRST + 1 must be a multiple of STEP.
///\ingroup cyclic_value
//***************************************************************************
template <typename T, const T FIRST = 0, const T LAST = 0, const T STEP = 1>
class cyclic_value
{
public:
//*************************************************************************
/// Constructor.
/// Sets 'first' and 'last' to the template parameter values.
/// The initial value is set to the first value.
//*************************************************************************
cyclic_value()
: value(FIRST),
first_value(FIRST),
last_value(LAST),
step_value(STEP)
{
STATIC_ASSERT(((LAST - FIRST + 1) % STEP) == 0, "LAST - FIRST + 1 is not a multiple of STEP");
}
//*************************************************************************
/// Constructor.
/// Sets the value to the first of the range.
///\param first The first value in the range.
///\param last The last value in the range.
//*************************************************************************
cyclic_value(const T& first_, const T& last_)
: value(first_),
first_value(first_),
last_value(last_),
step_value(STEP)
{
}
//*************************************************************************
/// Constructor.
/// Sets the value to the first of the range.
///\param first The first value in the range.
///\param last The last value in the range.
//*************************************************************************
cyclic_value(const T& first_, const T& last_, const T& step_)
: value(first_),
first_value(first_),
last_value(last_),
step_value(step_)
{
}
//*************************************************************************
/// Sets the range.
/// Sets the value to the first of the range.
///\param first The first value in the range.
///\param last The last value in the range.
///\param step The step value. Default = 1.
//*************************************************************************
void set(const T& first_, const T& last_, const T& step_ = 1)
{
first_value = first_;
last_value = last_;
step_value = step_;
value = first_;
#if ETL_USE_EXCEPTIONS
if (((last_value - first_value + 1) % step_value) != 0)
{
throw cyclic_value_illegal_range_exception();
}
#endif
}
//*************************************************************************
/// Resets the value to the first in the range.
//*************************************************************************
void to_first()
{
value = first_value;
}
//*************************************************************************
/// Resets the value to the last in the range.
//*************************************************************************
void to_last()
{
value = last_value;
}
//*************************************************************************
/// Advances to value by a number of steps.
///\param n The number of steps to advance.
//*************************************************************************
void advance(int n)
{
if (n > 0)
{
for (int i = 0; i < n; ++i)
{
operator ++();
}
}
else
{
for (int i = 0; i < -n; ++i)
{
operator --();
}
}
}
//*************************************************************************
/// Conversion operator.
/// \return The value of the underlying type.
//*************************************************************************
operator T()
{
return value;
}
//*************************************************************************
/// Const conversion operator.
/// \return The value of the underlying type.
//*************************************************************************
operator const T() const
{
return value;
}
//*************************************************************************
/// ++ operator.
//*************************************************************************
cyclic_value& operator ++()
{
if (value == last_value)
{
value = first_value;
}
else
{
value += step_value;
}
return *this;
}
//*************************************************************************
/// ++ operator.
//*************************************************************************
cyclic_value operator ++(int)
{
cyclic_value temp(*this);
operator++();
return temp;
}
//*************************************************************************
/// -- operator.
//*************************************************************************
cyclic_value& operator --()
{
if (value == first_value)
{
value = last_value;
}
else
{
value -= step_value;
}
return *this;
}
//*************************************************************************
/// -- operator.
//*************************************************************************
cyclic_value operator --(int)
{
cyclic_value temp(*this);
operator--();
return temp;
}
//*************************************************************************
/// Gets the first value.
//*************************************************************************
const T& first() const
{
return first_value;
}
//*************************************************************************
/// Gets the last value.
//*************************************************************************
const T& last() const
{
return last_value;
}
//*************************************************************************
/// Gets the last value.
//*************************************************************************
const T& step() const
{
return step_value;
}
//*************************************************************************
/// Gets the number of steps in a cycle.
//*************************************************************************
size_t number_of_steps() const
{
return (last_value - first_value + 1) / step_value;
}
private:
T first_value; ///< The first value in the range.
T last_value; ///< The last value in the range.
T step_value; ///< The value to step.
T value; ///< The current value.
};
}
#endif