213 lines
5.7 KiB
C++
213 lines
5.7 KiB
C++
/* Copyright (c) 2011 Wildfire Games
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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/*
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* static array, accessible modulo n
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*/
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#ifndef INCLUDED_ADTS_RING_BUF
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#define INCLUDED_ADTS_RING_BUF
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template<class T, size_t n> class RingBuf
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{
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size_t size_; // # of entries in buffer
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size_t head; // index of oldest item
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size_t tail; // index of newest item
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T data[n];
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public:
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RingBuf() : data() { clear(); }
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void clear() { size_ = 0; head = 0; tail = n-1; }
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size_t size() const { return size_; }
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bool empty() const { return size_ == 0; }
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const T& operator[](int ofs) const
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{
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ENSURE(!empty());
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size_t idx = (size_t)(head + ofs);
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return data[idx % n];
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}
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T& operator[](int ofs)
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{
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ENSURE(!empty());
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size_t idx = (size_t)(head + ofs);
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return data[idx % n];
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}
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T& front()
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{
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ENSURE(!empty());
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return data[head];
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}
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const T& front() const
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{
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ENSURE(!empty());
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return data[head];
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}
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T& back()
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{
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ENSURE(!empty());
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return data[tail];
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}
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const T& back() const
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{
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ENSURE(!empty());
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return data[tail];
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}
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void push_back(const T& item)
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{
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if(size_ < n)
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size_++;
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// do not complain - overwriting old values is legit
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// (e.g. sliding window).
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else
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head = (head + 1) % n;
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tail = (tail + 1) % n;
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data[tail] = item;
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}
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void pop_front()
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{
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if(size_ != 0)
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{
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size_--;
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head = (head + 1) % n;
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}
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else
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DEBUG_WARN_ERR(ERR::LOGIC); // underflow
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}
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class iterator
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{
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public:
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typedef std::random_access_iterator_tag iterator_category;
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typedef T value_type;
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typedef ptrdiff_t difference_type;
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typedef T* pointer;
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typedef T& reference;
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iterator() : data(0), pos(0)
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{}
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iterator(T* data_, size_t pos_) : data(data_), pos(pos_)
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{}
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T& operator[](int idx) const
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{ return data[(pos+idx) % n]; }
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T& operator*() const
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{ return data[pos % n]; }
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T* operator->() const
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{ return &**this; }
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iterator& operator++() // pre
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{ ++pos; return (*this); }
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iterator operator++(int) // post
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{ iterator tmp = *this; ++*this; return tmp; }
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bool operator==(const iterator& rhs) const
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{ return data == rhs.data && pos == rhs.pos; }
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bool operator!=(const iterator& rhs) const
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{ return !(*this == rhs); }
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bool operator<(const iterator& rhs) const
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{ return (pos < rhs.pos); }
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iterator& operator+=(difference_type ofs)
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{ pos += ofs; return *this; }
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iterator& operator-=(difference_type ofs)
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{ return (*this += -ofs); }
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iterator operator+(difference_type ofs) const
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{ iterator tmp = *this; return (tmp += ofs); }
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iterator operator-(difference_type ofs) const
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{ iterator tmp = *this; return (tmp -= ofs); }
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difference_type operator-(const iterator right) const
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{ return (difference_type)(pos - right.pos); }
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protected:
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T* data;
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size_t pos;
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// not mod-N so that begin != end when buffer is full.
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};
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class const_iterator
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{
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public:
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typedef std::random_access_iterator_tag iterator_category;
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typedef T value_type;
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typedef ptrdiff_t difference_type;
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typedef const T* pointer;
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typedef const T& reference;
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const_iterator() : data(0), pos(0)
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{}
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const_iterator(const T* data_, size_t pos_) : data(data_), pos(pos_)
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{}
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const T& operator[](int idx) const
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{ return data[(pos+idx) % n]; }
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const T& operator*() const
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{ return data[pos % n]; }
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const T* operator->() const
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{ return &**this; }
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const_iterator& operator++() // pre
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{ ++pos; return (*this); }
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const_iterator operator++(int) // post
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{ const_iterator tmp = *this; ++*this; return tmp; }
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bool operator==(const const_iterator& rhs) const
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{ return data == rhs.data && pos == rhs.pos; }
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bool operator!=(const const_iterator& rhs) const
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{ return !(*this == rhs); }
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bool operator<(const const_iterator& rhs) const
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{ return (pos < rhs.pos); }
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iterator& operator+=(difference_type ofs)
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{ pos += ofs; return *this; }
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iterator& operator-=(difference_type ofs)
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{ return (*this += -ofs); }
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iterator operator+(difference_type ofs) const
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{ iterator tmp = *this; return (tmp += ofs); }
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iterator operator-(difference_type ofs) const
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{ iterator tmp = *this; return (tmp -= ofs); }
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difference_type operator-(const iterator right) const
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{ return (difference_type)(pos - right.pos); }
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protected:
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const T* data;
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size_t pos;
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// not mod-N so that begin != end when buffer is full.
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};
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iterator begin()
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{
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return iterator(data, head);
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}
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const_iterator begin() const
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{
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return const_iterator(data, head);
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}
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iterator end()
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{
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return iterator(data, head+size_);
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}
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const_iterator end() const
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{
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return const_iterator(data, head+size_);
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}
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};
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#endif // #ifndef INCLUDED_ADTS_RING_BUF
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