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/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef __BLI_INDEX_RANGE_H__
#define __BLI_INDEX_RANGE_H__
/** \file
* \ingroup bli
*
* Allows passing iterators over ranges of integers without actually allocating an array or passing
* separate values. A range always has a step of one. If other step sizes are required in some
* cases, a separate data structure should be used.
*/
#include <algorithm>
#include <cmath>
#include <iostream>
#include "BLI_utildefines.h"
/* Forward declare tbb::blocked_range for conversion operations. */
namespace tbb {
template<typename Value> class blocked_range;
}
namespace BLI {
template<typename T> class ArrayRef;
class IndexRange {
private:
uint m_start = 0;
uint m_size = 0;
public:
IndexRange() = default;
explicit IndexRange(uint size) : m_start(0), m_size(size)
{
}
IndexRange(uint start, uint size) : m_start(start), m_size(size)
{
}
template<typename T>
IndexRange(const tbb::blocked_range<T> &range) : m_start(range.begin()), m_size(range.size())
{
}
class Iterator {
private:
uint m_current;
public:
Iterator(uint current) : m_current(current)
{
}
Iterator &operator++()
{
m_current++;
return *this;
}
bool operator!=(const Iterator &iterator) const
{
return m_current != iterator.m_current;
}
uint operator*() const
{
return m_current;
}
};
Iterator begin() const
{
return Iterator(m_start);
}
Iterator end() const
{
return Iterator(m_start + m_size);
}
/**
* Access an element in the range.
*/
uint operator[](uint index) const
{
BLI_assert(index < this->size());
return m_start + index;
}
/**
* Two ranges compare equal when they contain the same numbers.
*/
friend bool operator==(IndexRange a, IndexRange b)
{
return (a.m_size == b.m_size) && (a.m_start == b.m_start || a.m_size == 0);
}
/**
* Get the amount of numbers in the range.
*/
uint size() const
{
return m_size;
}
/**
* Create a new range starting at the end of the current one.
*/
IndexRange after(uint n) const
{
return IndexRange(m_start + m_size, n);
}
/**
* Create a new range that ends at the start of the current one.
*/
IndexRange before(uint n) const
{
return IndexRange(m_start - n, n);
}
/**
* Get the first element in the range.
* Asserts when the range is empty.
*/
uint first() const
{
BLI_assert(this->size() > 0);
return m_start;
}
/**
* Get the last element in the range.
* Asserts when the range is empty.
*/
uint last() const
{
BLI_assert(this->size() > 0);
return m_start + m_size - 1;
}
/**
* Get the element one after the end. The returned value is undefined when the range is empty.
*/
uint one_after_last() const
{
return m_start + m_size;
}
/**
* Get the first element in the range. The returned value is undefined when the range is empty.
*/
uint start() const
{
return m_start;
}
/**
* Returns true when the range contains a certain number, otherwise false.
*/
bool contains(uint value) const
{
return value >= m_start && value < m_start + m_size;
}
IndexRange slice(uint start, uint size) const
{
uint new_start = m_start + start;
BLI_assert(new_start + size <= m_start + m_size || size == 0);
return IndexRange(new_start, size);
}
IndexRange slice(IndexRange range) const
{
return this->slice(range.start(), range.size());
}
/**
* Get read-only access to a memory buffer that contains the range as actual numbers.
*/
ArrayRef<uint> as_array_ref() const;
friend std::ostream &operator<<(std::ostream &stream, IndexRange range)
{
stream << "[" << range.start() << ", " << range.one_after_last() << ")";
return stream;
}
};
} // namespace BLI
#endif /* __BLI_INDEX_RANGE_H__ */
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