146 lines
3.6 KiB
C++
146 lines
3.6 KiB
C++
// SPDX-License-Identifier: MIT
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// Copyright 2011, SIL International, All rights reserved.
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#pragma once
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#include <iterator>
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#include <utility>
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#include "inc/Main.h"
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namespace graphite2 {
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// A read-only packed fast sparse array of uint16_t with uint16_t keys.
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// Like most container classes this has capacity and size properties and these
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// refer to the number of stored entries and the number of addressable entries
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// as normal. However due the sparse nature the capacity is always <= than the
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// size.
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class sparse
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{
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public:
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typedef uint16_t key_type;
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typedef uint16_t mapped_type;
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typedef std::pair<const key_type, mapped_type> value_type;
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private:
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typedef unsigned long mask_t;
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static const unsigned char SIZEOF_CHUNK = (sizeof(mask_t) - sizeof(key_type))*8;
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struct chunk
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{
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mask_t mask:SIZEOF_CHUNK;
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key_type offset;
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};
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static const chunk empty_chunk;
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sparse(const sparse &);
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sparse & operator = (const sparse &);
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public:
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template<typename I>
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sparse(I first, const I last);
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sparse() throw();
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~sparse() throw();
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operator bool () const throw();
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mapped_type operator [] (const key_type k) const throw();
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size_t capacity() const throw();
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size_t size() const throw();
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size_t _sizeof() const throw();
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CLASS_NEW_DELETE;
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private:
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union {
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chunk * map;
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mapped_type * values;
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} m_array;
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key_type m_nchunks;
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};
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inline
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sparse::sparse() throw() : m_nchunks(0)
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{
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m_array.map = const_cast<graphite2::sparse::chunk *>(&empty_chunk);
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}
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template <typename I>
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sparse::sparse(I attr, const I last)
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: m_nchunks(0)
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{
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m_array.map = 0;
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// Find the maximum extent of the key space.
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size_t n_values=0;
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long lastkey = -1;
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for (I i = attr; i != last; ++i, ++n_values)
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{
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const typename std::iterator_traits<I>::value_type v = *i;
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if (v.second == 0) { --n_values; continue; }
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if (v.first <= lastkey) { m_nchunks = 0; return; }
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lastkey = v.first;
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const key_type k = v.first / SIZEOF_CHUNK;
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if (k >= m_nchunks) m_nchunks = k+1;
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}
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if (m_nchunks == 0)
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{
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m_array.map=const_cast<graphite2::sparse::chunk *>(&empty_chunk);
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return;
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}
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m_array.values = grzeroalloc<mapped_type>((m_nchunks*sizeof(chunk) + sizeof(mapped_type)-1)
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/ sizeof(mapped_type)
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+ n_values);
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if (m_array.values == 0)
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return;
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// coverity[forward_null : FALSE] Since m_array is union and m_array.values is not NULL
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chunk * ci = m_array.map;
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ci->offset = (m_nchunks*sizeof(chunk) + sizeof(mapped_type)-1)/sizeof(mapped_type);
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mapped_type * vi = m_array.values + ci->offset;
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for (; attr != last; ++attr, ++vi)
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{
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const typename std::iterator_traits<I>::value_type v = *attr;
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if (v.second == 0) { --vi; continue; }
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chunk * const ci_ = m_array.map + v.first/SIZEOF_CHUNK;
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if (ci != ci_)
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{
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ci = ci_;
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ci->offset = key_type(vi - m_array.values);
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}
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ci->mask |= 1UL << (SIZEOF_CHUNK - 1 - (v.first % SIZEOF_CHUNK));
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*vi = v.second;
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}
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}
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inline
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sparse::operator bool () const throw()
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{
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return m_array.map != 0;
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}
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inline
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size_t sparse::size() const throw()
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{
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return m_nchunks*SIZEOF_CHUNK;
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}
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inline
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size_t sparse::_sizeof() const throw()
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{
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return sizeof(sparse) + capacity()*sizeof(mapped_type) + m_nchunks*sizeof(chunk);
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}
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} // namespace graphite2
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