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#ifndef INC_CircularQueue_hpp__ |
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#define INC_CircularQueue_hpp__ |
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|
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/* ANTLR Translator Generator |
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* Project led by Terence Parr at http://www.jGuru.com |
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* Software rights: http://www.antlr.org/license.html |
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* |
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* $Id$ |
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*/ |
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|
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#include <antlr/config.hpp> |
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#include <antlr/Token.hpp> |
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#include <vector> |
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#include <cassert> |
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|
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#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE |
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namespace antlr { |
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#endif |
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|
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// Resize every 5000 items |
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#define OFFSET_MAX_RESIZE 5000 |
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|
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template <class T> |
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class ANTLR_API CircularQueue { |
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public: |
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CircularQueue() |
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: storage() |
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, m_offset(0) |
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{ |
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} |
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~CircularQueue() |
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{ |
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} |
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|
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/// Clear the queue |
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inline void clear( void ) |
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{ |
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m_offset = 0; |
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storage.clear(); |
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} |
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|
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/// @todo this should use at or should have a check |
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inline T elementAt( size_t idx ) const |
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{ |
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return storage[idx+m_offset]; |
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} |
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void removeFirst() |
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{ |
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if (m_offset >= OFFSET_MAX_RESIZE) |
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{ |
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storage.erase( storage.begin(), storage.begin() + m_offset + 1 ); |
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m_offset = 0; |
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} |
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else |
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++m_offset; |
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} |
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inline void removeItems( size_t nb ) |
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{ |
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// it would be nice if we would not get called with nb > entries |
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// (or to be precise when entries() == 0) |
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// This case is possible when lexer/parser::recover() calls |
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// consume+consumeUntil when the queue is empty. |
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// In recover the consume says to prepare to read another |
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// character/token. Then in the subsequent consumeUntil the |
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// LA() call will trigger |
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// syncConsume which calls this method *before* the same queue |
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// has been sufficiently filled. |
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if( nb > entries() ) |
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nb = entries(); |
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|
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if (m_offset >= OFFSET_MAX_RESIZE) |
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{ |
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storage.erase( storage.begin(), storage.begin() + m_offset + nb ); |
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m_offset = 0; |
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} |
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else |
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m_offset += nb; |
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} |
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inline void append(const T& t) |
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{ |
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storage.push_back(t); |
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} |
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inline size_t entries() const |
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{ |
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return storage.size() - m_offset; |
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} |
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|
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private: |
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ANTLR_USE_NAMESPACE(std)vector<T> storage; |
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size_t m_offset; |
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|
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CircularQueue(const CircularQueue&); |
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const CircularQueue& operator=(const CircularQueue&); |
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}; |
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|
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#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE |
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} |
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#endif |
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|
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#endif //INC_CircularQueue_hpp__ |
