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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;

    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

        // 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_