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/*
* $Id: head.c,v 1.7 2004/05/21 08:48:39 radim Exp $
*
****************************************************************************
*
* MODULE: Vector library
*
* AUTHOR(S): Original author CERL, probably Dave Gerdes.
* Update to GRASS 5.7 Radim Blazek.
*
* PURPOSE: Lower level functions for reading/writing/manipulating vectors.
*
* COPYRIGHT: (C) 2001 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.
*
*****************************************************************************/
#include <string.h>
#include "gis.h"
#include "Vect.h"
int
dig__write_head ( struct Map_info *Map )
{
unsigned char buf[10];
long length = GV_COOR_HEAD_SIZE;
G_debug ( 1, "dig__write_head()");
dig_set_cur_port (&(Map->head.port));
dig_fseek ( &(Map->dig_fp), 0L, 0);
/* bytes 1 - 5 */
buf[0] = Map->head.Version_Major;
buf[1] = Map->head.Version_Minor;
buf[2] = Map->head.Back_Major;
buf[3] = Map->head.Back_Minor;
buf[4] = Map->head.port.byte_order;
if (0 >= dig__fwrite_port_C ( buf, 5, &(Map->dig_fp) )) return (0);
/* bytes 6 - 9 : header size */
if (0 >= dig__fwrite_port_L ( &length, 1, &(Map->dig_fp) )) return (0);
/* byte 10 : dimension 2D or 3D */
buf[0] = Map->head.with_z;
if (0 >= dig__fwrite_port_C ( buf, 1, &(Map->dig_fp) )) return (0);
/* bytes 11 - 14 : size of coordinate file */
G_debug ( 1, "write coor size (%ld) to head", Map->head.size);
if (0 >= dig__fwrite_port_L ( &(Map->head.size), 1, &(Map->dig_fp) )) return (0);
G_debug (2, "coor body offset %d", dig_ftell( &(Map->dig_fp) ));
return (1);
}
int
dig__read_head ( struct Map_info *Map )
{
unsigned char buf[10];
struct Port_info port;
dig_fseek ( &(Map->dig_fp), 0L, 0);
/* bytes 1 - 5 */
if (0 >= dig__fread_port_C ( buf, 5, &(Map->dig_fp) )) return (0);
Map->head.Version_Major = buf[0];
Map->head.Version_Minor = buf[1];
Map->head.Back_Major = buf[2];
Map->head.Back_Minor = buf[3];
Map->head.port.byte_order = buf[4];
G_debug (2, "Coor header: file version %d.%d , supported from GRASS version %d.%d",
Map->head.Version_Major, Map->head.Version_Minor,
Map->head.Back_Major, Map->head.Back_Minor );
G_debug (2, " byte order %d", Map->head.port.byte_order );
/* check version numbers */
if ( Map->head.Version_Major > GV_COOR_VER_MAJOR || Map->head.Version_Minor > GV_COOR_VER_MINOR ) {
/* The file was created by GRASS library with higher version than this one */
if ( Map->head.Back_Major > GV_COOR_VER_MAJOR || Map->head.Back_Minor > GV_COOR_VER_MINOR ) {
/* This version of GRASS lib is lower than the oldest which can read this format */
G_fatal_error ( "Vector 'coor' format version %d.%d is not supported by this version of GRASS. "
"Update your GRASS.", Map->head.Version_Major, Map->head.Version_Minor);
return (-1);
}
G_warning ( "Your GRASS version does not fully support vector format %d.%d."
" Consider to upgrade GRASS.",
Map->head.Version_Major, Map->head.Version_Minor );
}
dig_init_portable ( &port, Map->head.port.byte_order);
dig_set_cur_port (&port);
/* bytes 6 - 9 : header size */
if (0 >= dig__fread_port_L ( &(Map->head.head_size), 1, &(Map->dig_fp) )) return (0);
G_debug (2, " header size %d", Map->head.head_size );
/* byte 10 : dimension 2D or 3D */
if (0 >= dig__fread_port_C ( buf, 1, &(Map->dig_fp) )) return (0);
Map->head.with_z = buf[0];
G_debug (2, " with_z %d", Map->head.with_z );
/* bytes 11 - 14 : size of coordinate file */
if (0 >= dig__fread_port_L ( &(Map->head.size), 1, &(Map->dig_fp) )) return (0);
G_debug (2, " coor size %d", Map->head.size );
/* Go to end of header, file may be written by new version of GRASS with longer header */
dig_fseek ( &(Map->dig_fp), Map->head.head_size, SEEK_SET );
return (1);
}
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