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Diffstat (limited to 'lib/antlr/antlr/CircularQueue.h')
-rw-r--r-- | lib/antlr/antlr/CircularQueue.h | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/lib/antlr/antlr/CircularQueue.h b/lib/antlr/antlr/CircularQueue.h new file mode 100644 index 00000000..89c593a1 --- /dev/null +++ b/lib/antlr/antlr/CircularQueue.h @@ -0,0 +1,100 @@ +#ifndef INC_CircularQueue_h__ +#define INC_CircularQueue_h__ + +/* ANTLR Translator Generator + * Project led by Terence Parr at http://www.jGuru.com + * Software rights: http://www.antlr.org/license.html + * + * $Id$ + */ + +#include <antlr/config.h> +#include <antlr/Token.h> +#include <vector> +#include <cassert> + +#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE +namespace antlr { +#endif + +// Resize every 5000 items +#define OFFSET_MAX_RESIZE 5000 + +template <class T> +class ANTLR_API CircularQueue { +public: + CircularQueue() + : storage() + , m_offset(0) + { + } + ~CircularQueue() + { + } + + /// Clear the queue + inline void clear( void ) + { + m_offset = 0; + storage.clear(); + } + + /// @todo this should use at or should have a check + inline T elementAt( size_t idx ) const + { + return storage[idx+m_offset]; + } + void removeFirst() + { + if (m_offset >= OFFSET_MAX_RESIZE) + { + storage.erase( storage.begin(), storage.begin() + m_offset + 1 ); + m_offset = 0; + } + else + ++m_offset; + } + inline void removeItems( size_t nb ) + { + // it would be nice if we would not get called with nb > entries + // (or to be precise when entries() == 0) + // This case is possible when lexer/parser::recover() calls + // consume+consumeUntil when the queue is empty. + // In recover the consume says to prepare to read another + // character/token. Then in the subsequent consumeUntil the + // LA() call will trigger + // syncConsume which calls this method *before* the same queue + // has been sufficiently filled. + if( nb > entries() ) + nb = entries(); + + if (m_offset >= OFFSET_MAX_RESIZE) + { + storage.erase( storage.begin(), storage.begin() + m_offset + nb ); + m_offset = 0; + } + else + m_offset += nb; + } + inline void append(const T& t) + { + storage.push_back(t); + } + inline size_t entries() const + { + return storage.size() - m_offset; + } + +private: + ANTLR_USE_NAMESPACE(std)vector<T> storage; + size_t m_offset; + + CircularQueue(const CircularQueue&); + const CircularQueue& operator=(const CircularQueue&); +}; + +#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE +} +#endif + +#endif //INC_CircularQueue_h__ |