Alignment/Geners/interface/ColumnBuffer.hh - master - githubmirror/cmssw

Alignment/Geners/interface/ColumnBuffer.hh
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08 май 2019, 15:16
08 май 2019, 15:167614b05
#ifndef GENERS_COLUMNBUFFER_HH_
#define GENERS_COLUMNBUFFER_HH_

#include <iostream>
#include <vector>

#include "Alignment/Geners/interface/CharBuffer.hh"
#include "Alignment/Geners/interface/ClassId.hh"

namespace gs {
  namespace Private {
    struct ColumnBuffer {
      inline ColumnBuffer() : firstrow(0), lastrowp1(0), podsize(0) {}

      // The actual buffer
      CharBuffer buf;

      // The range of rows stored in the buffer is [firstrow, lastrowp1)
      unsigned long firstrow;
      unsigned long lastrowp1;

      // The following member will be non-0 if the column
      // members are PODs for I/O purposes
      unsigned long podsize;

      // If the above member is 0, objects in the buffer may have
      // variable size. Because of this, we need to store an offset
      // of each object separately. To conserve space, the vector
      // of object offsets is not filled for PODs.
      std::vector<std::streampos> offsets;

      // Methods related to I/O
      bool write(std::ostream &os) const;
      inline const ClassId &classId() const { return static_classId(); }

      // The "restore" method is special and requires
      // use of special references. The reason is the
      // following: we will likely store a large number
      // of these buffers at a time. Storing the class id
      // of CharBuffer every time would be a waste of
      // storage space. Because of this, we will assume
      // that the code that manages these buffers will
      // stash the CharBuffer class id somewhere.
      static void restore(const ClassId &id, const ClassId &charBufId, std::istream &in, ColumnBuffer *buf);

      static inline const char *classname() { return "gs::Private::ColumnBuffer"; }
      static inline unsigned version() { return 1; }

      bool operator==(const ColumnBuffer &r) const;
      inline bool operator!=(const ColumnBuffer &r) const { return !(*this == r); }

    private:
      static const ClassId &static_classId();
    };
  }  // namespace Private
}  // namespace gs

#endif  // GENERS_COLUMNBUFFER_HH_