Geografic-Information-System/lib/vector/Vlib/rewind_nat.c

/*!
   \file lib/vector/Vlib/rewind.c

   \brief Vector library - rewind data (native format)

   Higher level functions for reading/writing/manipulating vectors.

   (C) 2001-2009, 2011-2012 by the GRASS Development Team

   This program is free software under the GNU General Public License
   (>=v2). Read the file COPYING that comes with GRASS for details.

   \author Original author CERL, probably Dave Gerdes or Mike Higgins.
   \author Update to GRASS 5.7 Radim Blazek and David D. Gray.
*/

#include <grass/vector.h>

/*! \brief Rewind vector map to cause reads to start at beginning on
  non-topological level (level 1) - native format - internal use only
  
  \param Map pointer to Map_info struct

  \return 0 on success
  \return -1 on error
*/
int V1_rewind_nat(struct Map_info *Map)
{
    return dig_fseek(&(Map->dig_fp), Map->head.head_size, SEEK_SET);
}

/*! \brief Rewind vector map to cause reads to start at beginning on
  topological level (level 2) - native format - internal use only

  \param Map pointer to Map_info struct

  \return 0 on success
  \return -1 on error
*/
int V2_rewind_nat(struct Map_info *Map)
{
    Map->next_line = 1;
    return V1_rewind_nat(Map);	/* make sure level 1 reads are reset too */
}