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