forked from mirrors/0ad
Removes unused DynHashTbl. Last usage was removed in 6c915291cc.
STL or Boost provides containers with DynHashTbl's functionality (and not worse performance). Refs9fd08fb044,5ca66fc757. This was SVN commit r25519.
This commit is contained in:
vladislavbelov
@@ -1,238 +0,0 @@
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/* 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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* dynamic (grow-able) hash table
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*/
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#ifndef INCLUDED_ADTS_DYN_HASH_TBL
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#define INCLUDED_ADTS_DYN_HASH_TBL
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#include <string.h> // strcmp
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#include "lib/fnv_hash.h"
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template<typename Key, typename T> class DHT_Traits
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{
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public:
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static const size_t initial_entries = 16;
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size_t hash(Key key) const;
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bool equal(Key k1, Key k2) const;
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Key get_key(T t) const;
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};
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template<> class DHT_Traits<const char*, const char*>
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{
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public:
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static const size_t initial_entries = 512;
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size_t hash(const char* key) const
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{
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return (size_t)fnv_lc_hash(key);
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}
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bool equal(const char* k1, const char* k2) const
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{
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return !strcmp(k1, k2);
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}
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const char* get_key(const char* t) const
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{
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return t;
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}
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};
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// intended for pointer types
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template<typename Key, typename T, typename Traits=DHT_Traits<Key,T> >
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class DynHashTbl
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{
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T* tbl;
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u16 num_entries;
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u16 max_entries; // when initialized, = 2**n for faster modulo
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Traits tr;
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T& get_slot(Key key) const
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{
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size_t hash = tr.hash(key);
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ENSURE(max_entries != 0); // otherwise, mask will be incorrect
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const size_t mask = max_entries-1;
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for(;;)
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{
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T& t = tbl[hash & mask];
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// empty slot encountered => not found
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if(!t)
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return t;
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// keys are actually equal => found it
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if(tr.equal(key, tr.get_key(t)))
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return t;
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// keep going (linear probing)
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hash++;
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}
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}
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void expand_tbl()
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{
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// alloc a new table (but don't assign it to <tbl> unless successful)
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T* old_tbl = tbl;
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tbl = (T*)calloc(max_entries*2, sizeof(T));
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if(!tbl)
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{
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tbl = old_tbl;
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throw std::bad_alloc();
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}
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max_entries *= 2;
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// must be set before get_slot
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// newly initialized, nothing to copy - done
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if(!old_tbl)
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return;
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// re-hash from old table into the new one
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for(size_t i = 0; i < max_entries/2u; i++)
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{
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T t = old_tbl[i];
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if(t)
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get_slot(tr.get_key(t)) = t;
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}
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free(old_tbl);
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}
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public:
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DynHashTbl()
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{
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tbl = 0;
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clear();
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}
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~DynHashTbl()
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{
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free(tbl);
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}
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void clear()
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{
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// must remain usable after calling clear, so shrink the table to
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// its initial size but don't deallocate it completely
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SAFE_FREE(tbl);
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num_entries = 0;
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// rationale: must not set to 0 because expand_tbl only doubles the size.
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// don't keep the previous size when clearing because it may have become
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// huge and there is no provision for shrinking.
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max_entries = tr.initial_entries/2; // will be doubled in expand_tbl
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expand_tbl();
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}
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void insert(const Key key, const T t)
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{
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// more than 75% full - increase table size.
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// do so before determining slot; this will invalidate previous pnodes.
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if(num_entries*4 >= max_entries*3)
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expand_tbl();
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T& slot = get_slot(key);
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ENSURE(slot == 0); // not already present
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slot = t;
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num_entries++;
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}
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T find(Key key) const
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{
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return get_slot(key);
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}
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size_t size() const
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{
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return num_entries;
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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::forward_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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iterator()
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{
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}
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iterator(T* pos_, T* end_) : pos(pos_), end(end_)
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{
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}
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T& operator*() const
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{
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return *pos;
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}
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iterator& operator++() // pre
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{
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do
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pos++;
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while(pos != end && *pos == 0);
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return (*this);
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}
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bool operator==(const iterator& rhs) const
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{
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return pos == rhs.pos;
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}
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bool operator<(const iterator& rhs) const
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{
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return (pos < rhs.pos);
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}
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// derived
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const T* operator->() const
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{
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return &**this;
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}
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bool operator!=(const iterator& rhs) const
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{
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return !(*this == rhs);
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}
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iterator operator++(int) // post
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{
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iterator tmp = *this; ++*this; return tmp;
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}
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protected:
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T* pos;
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T* end;
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// only used when incrementing (avoid going beyond end of table)
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};
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iterator begin() const
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{
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T* pos = tbl;
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while(pos != tbl+max_entries && *pos == 0)
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pos++;
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return iterator(pos, tbl+max_entries);
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}
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iterator end() const
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{
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return iterator(tbl+max_entries, 0);
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}
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};
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#endif // #ifndef INCLUDED_ADTS_DYN_HASH_TBL
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