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#ifndef HLSLTOKENSTREAM_H_

#define HLSLTOKENSTREAM_H_

#include "hlslScanContext.h"

namespace glslang {

    class HlslTokenStream {

    public:

        explicit HlslTokenStream(HlslScanContext& scanner)

            : scanner(scanner), preTokenStackSize(0), tokenBufferPos(0) { }

        virtual ~HlslTokenStream() { }

    public:

        void advanceToken();

        void recedeToken();

        bool acceptTokenClass(EHlslTokenClass);

        EHlslTokenClass peek() const;

        bool peekTokenClass(EHlslTokenClass) const;

        glslang::TBuiltInVariable mapSemantic(const char* upperCase) { return scanner.mapSemantic(upperCase); }

        void pushTokenStream(const TVector<HlslToken>* tokens);

        void popTokenStream();

    protected:

        HlslToken token;                  // the token we are currently looking at, but have not yet accepted

    private:

        HlslTokenStream();

        HlslTokenStream& operator=(const HlslTokenStream&);

        HlslScanContext& scanner;         // lexical scanner, to get next token from source file

        TVector<const TVector<HlslToken>*> tokenStreamStack; // for getting the next token from an existing vector of tokens

        TVector<int> tokenPosition;

        TVector<HlslToken> currentTokenStack;

        // This is the number of tokens we can recedeToken() over.

        static const int tokenBufferSize = 2;

        // Previously scanned tokens, returned for future advances,

        // so logically in front of the token stream.

        // Is logically a stack; needs last in last out semantics.

        // Currently implemented as a stack of size 2.

        HlslToken preTokenStack[tokenBufferSize];

        int preTokenStackSize;

        void pushPreToken(const HlslToken&);

        HlslToken popPreToken();

        // Previously scanned tokens, not yet returned for future advances,

        // but available for that.

        // Is logically a fifo for normal advances, and a stack for recession.

        // Currently implemented with an intrinsic size of 2.

        HlslToken tokenBuffer[tokenBufferSize];

        int tokenBufferPos;

        void pushTokenBuffer(const HlslToken&);

        HlslToken popTokenBuffer();

    };

} // end namespace glslang

#endif // HLSLTOKENSTREAM_H_