core/sql/executor/BufferReference.h

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// Licensed to the Apache Software Foundation (ASF) under one
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//
// BufferReference.h
//

#ifndef BUFFERREFERENCE_H
#define BUFFERREFERENCE_H

#include <NABasicObject.h>
#include "ExOverflow.h"

namespace ExOverflow
{
  class BufferReference : public NABasicObject
  {
  public:
    BufferReference(ByteCount bufferSize);
    BufferReference(const BufferReference& br);
    ~BufferReference(void);

    BufferReference& operator=(const BufferReference& rhs);

    // Advance buffer position numBytes
    void advance(ByteCount numBytes);

    // Byte available in buffer
    ByteCount bytesAvailable(void) const;

    // Get pointer to beginning of buffer
    char* getBuffer(void) const;

    // Get buffer position
    char* getPosition(void) const;

    // Invalidate buffer reference
    void invalidate(void);

    // Is buffer reference valid?
    bool isValid(void) const;

    // Byte offset of current buffer position
    BufferOffset getOffset(void) const;

    // Do both references refer to same buffer?
    static bool sameBuffer(const BufferReference& left, 
                           const BufferReference& right);

    // Do reference and pointer refer to same buffer?
    static bool sameBuffer(const BufferReference& left, 
                           const char* right);

    // Set buffer reference to beginning of buffer
    void set(char* buffer);

    // Set buffer reference to buffer position
    void set(char* buffer, BufferOffset offset);

  private:
    char* buffer_;            // buffer base
    BufferOffset maxOffset_;  // valid offset range is (0..maxOffset_-1)
    BufferOffset offset_;     // position within buffer_
  };

  inline
  char*
  BufferReference::getBuffer(void) const
  {
    return buffer_;
  }

  inline
  char*
  BufferReference::getPosition(void) const
  {
    return (buffer_ + offset_);
  }

  inline
  bool
  BufferReference::isValid(void) const
  {
    return (buffer_ != NULL);
  }

  inline
  BufferOffset
  BufferReference::getOffset(void) const
  {
    return offset_;
  }

  inline
  void 
  BufferReference::set(char* buffer)
  {
    set(buffer, 0);
  }
}

#endif