antlr/include/antlr/InputBuffer.hpp

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#ifndef INC_InputBuffer_hpp__
#define INC_InputBuffer_hpp__

/* ANTLR Translator Generator
 * Project led by Terence Parr at http://www.jGuru.com
 * Software rights: http://www.antlr.org/license.html
 *
 * $Id: //depot/code/org.antlr/release/antlr-2.7.7/lib/cpp/antlr/InputBuffer.hpp#2 $
 */

#include <antlr/config.hpp>
#include <antlr/CircularQueue.hpp>
#include <string>

#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
namespace antlr {
#endif

class ANTLR_API InputBuffer {
public:
        InputBuffer()
        : nMarkers(0)
        , markerOffset(0)
        , numToConsume(0)
        {
        }

        virtual ~InputBuffer()
        {
        }

        virtual inline void reset( void )
        {
                nMarkers = 0;
                markerOffset = 0;
                numToConsume = 0;
                queue.clear();
        }

        inline void commit( void )
        {
                nMarkers--;
        }

        virtual inline void consume()
        {
                numToConsume++;
        }

        virtual void fill(unsigned int amount);

        virtual int getChar()=0;

        virtual inline int LA(unsigned int i)
        {
                fill(i);
                return queue.elementAt(markerOffset + i - 1);
        }

        virtual unsigned int mark();
        virtual inline bool isMarked() const
        {
                return (nMarkers != 0);
        }
        virtual void rewind(unsigned int mark);

        virtual unsigned int entries() const;

        ANTLR_USE_NAMESPACE(std)string getLAChars() const;

        ANTLR_USE_NAMESPACE(std)string getMarkedChars() const;

protected:
        // char source
        // leave to subclasses

        // Number of active markers
        unsigned int nMarkers; // = 0;

        // Additional offset used when markers are active
        unsigned int markerOffset; // = 0;

        // Number of calls to consume() since last LA() or LT() call
        unsigned int numToConsume; // = 0;

        // Circular queue
        CircularQueue<int> queue;

        void syncConsume();

private:
        InputBuffer(const InputBuffer& other);
        InputBuffer& operator=(const InputBuffer& other);
};

inline void InputBuffer::syncConsume() {
        if (numToConsume > 0)
        {
                if (nMarkers > 0)
                        markerOffset += numToConsume;
                else
                        queue.removeItems( numToConsume );
                numToConsume = 0;
        }
}

#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
}
#endif

#endif //INC_InputBuffer_hpp__

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