storage/mroonga/lib/mrn_table_fields_offset_mover.cpp


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/* -*- c-basic-offset: 2 -*- */
/*
  Copyright(C) 2017 Kouhei Sutou <kou@clear-code.com>

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1335  USA
*/

#include "mrn_table_fields_offset_mover.hpp"

namespace mrn {
  FieldTableChanger::FieldTableChanger(TABLE *table,
                                       TABLE *new_table)
    : old_table_(table),
      new_table_(new_table) {
    my_ptrdiff_t diff =
            PTR_BYTE_DIFF(new_table_->record[0], old_table_->record[0]);
    uint n_columns = old_table_->s->fields;
    for (uint i = 0; i < n_columns; ++i) {
      Field *field = old_table_->field[i];
      field->move_field_offset(diff);
      field->table = new_table;
    }
  }

  FieldTableChanger::~FieldTableChanger() {
    my_ptrdiff_t diff =
            PTR_BYTE_DIFF(new_table_->record[0], old_table_->record[0]);
    uint n_columns = old_table_->s->fields;
    for (uint i = 0; i < n_columns; ++i) {
      Field *field = old_table_->field[i];
      field->move_field_offset(-diff);
      field->table = old_table_;
    }
  }
}