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

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

   \brief Vector library - write/modify vector feature (native format)

   Higher level functions for reading/writing/manipulating vectors.

   Operations:
    - Add feature
    - Rewrite feature
    - Delete feature
    - Restore feature

   (C) 2001-2010 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.
   \author V*_restore_line() by Martin Landa <landa.martin gmail.com> (2008)
 */

#include <grass/config.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#include <grass/gis.h>
#include <grass/vector.h>
#include <grass/glocale.h>

static off_t rewrite_line_nat(struct Map_info *, off_t, int,
			      const struct line_pnts *, const struct line_cats *);

/*!
  \brief Writes feature to 'coor' file (level 1)
  
  \param Map pointer to Map_info structure
  \param type feature type
  \param points feature geometry
  \param cats feature categories
  
  \return feature offset into file
  \return -1 on error
*/
off_t V1_write_line_nat(struct Map_info *Map,
		       int type, const struct line_pnts *points, const struct line_cats *cats)
{
    off_t offset;

    if (dig_fseek(&(Map->dig_fp), 0L, SEEK_END) == -1)	/* set to  end of file */
	return -1;

    offset = dig_ftell(&(Map->dig_fp));
    if (offset == -1)
	return -1;

    return rewrite_line_nat(Map, offset, type, points, cats);
}

/*!
  \brief Writes feature to 'coor' file (topology level)
  
  \param Map pointer to Map_info structure
  \param type feature type
  \param points feature geometry
  \param cats feature categories
  
  \return new feature id
  \return -1 on error
*/
off_t V2_write_line_nat(struct Map_info *Map,
			int type, const struct line_pnts *points, const struct line_cats *cats)
{
    return V2__write_line(Map, type, points, cats, V1_write_line_nat);
}

/*!
  \brief Rewrites feature at the given offset (level 1)
  
  If the number of points or cats differs from the original one or
  the type is changed: GV_POINTS -> GV_LINES or GV_LINES ->
  GV_POINTS, the old one is deleted and the new is appended to the
  end of the file.
  
  Old feature is deleted (marked as dead), new feature written.
  
  \param Map pointer to Map_info structure
  \param offset feature offset
  \param type feature type
  \param points feature geometry
  \param cats feature categories
  
  \return feature offset (rewriten feature)
  \return -1 on error
*/
off_t V1_rewrite_line_nat(struct Map_info *Map,
			  off_t offset,
			  int type,
			  const struct line_pnts *points, const struct line_cats *cats)
{
    int old_type;
    struct line_pnts *old_points;
    struct line_cats *old_cats;
    off_t new_offset;
    
    /* TODO: enable points and cats == NULL  */

    /* First compare numbers of points and cats with tha old one */
    old_points = Vect_new_line_struct();
    old_cats = Vect_new_cats_struct();

    old_type = V1_read_line_nat(Map, old_points, old_cats, offset);
    if (old_type == -1)
	return (-1);		/* error */

    if (old_type != -2		/* EOF -> write new line */
	&& points->n_points == old_points->n_points
	&& cats->n_cats == old_cats->n_cats
	&& (((type & GV_POINTS) && (old_type & GV_POINTS))
	    || ((type & GV_LINES) && (old_type & GV_LINES)))) {

	/* equal -> overwrite the old */
	return rewrite_line_nat(Map, offset, type, points, cats);
    }
    else {
	/* differ -> delete the old and append new */
	/* delete old */
	V1_delete_line_nat(Map, offset);

	/* write new */
	if (dig_fseek(&(Map->dig_fp), 0L, SEEK_END) == -1)	/*  end of file */
	    return -1;

	new_offset = dig_ftell(&(Map->dig_fp));
	if (new_offset == -1)
	    return -1;

	return rewrite_line_nat(Map, new_offset, type, points, cats);
    }
}

/*!
  \brief Rewrites feature (topology level)
   
  Old feature is deleted (marked as dead), new feature written.
  
  \param Map pointer to Map_info structure
  \param line feature id
  \param type feature type
  \param points feature geometry
  \param cats feature category
  
  \return new feature id
  \return -1 on error
*/
int V2_rewrite_line_nat(struct Map_info *Map,
			int line,
			int type,
			const struct line_pnts *points, const struct line_cats *cats)
{
    /* TODO: this is just quick shortcut because we have already V2_delete_nat()
     *        and V2_write_nat() this function first deletes old line
     *        and then writes new one. It is not very effective if number of points
     *        and cats was not changed or topology is not changed (nodes not moved,
     *        angles not changed etc.) */

    V2_delete_line_nat(Map, line);

    return (V2_write_line_nat(Map, type, points, cats));
}

/*!
  \brief Rewrites feature at the given offset.
  
  \param Map pointer to Map_info structure
  \param offset feature offset
  \param type feature type
  \param points feature geometry
  \param cats feature categories
  
  \return feature offset
  \return -1 on error
*/
off_t rewrite_line_nat(struct Map_info *Map,
		       off_t offset,
		       int type,
		       const struct line_pnts *points, const struct line_cats *cats)
{
    int i, n_points;
    char rhead, nc;
    short field;
    struct gvfile *dig_fp;

    dig_set_cur_port(&(Map->head.port));
    dig_fp = &(Map->dig_fp);

    if (dig_fseek(dig_fp, offset, 0) == -1)
	return -1;

    /* first byte:   0 bit: 1 - alive, 0 - dead
     *                1 bit: 1 - categories, 0 - no category
     *              2-3 bit: store type
     *              4-5 bit: reserved for store type expansion
     *              6-7 bit: not used  
     */

    rhead = (char)dig_type_to_store(type);
    rhead <<= 2;
    if (cats->n_cats > 0) {
	rhead |= 0x02;
    }
    rhead |= 0x01;		/* written/rewritten is always alive */

    if (0 >= dig__fwrite_port_C(&rhead, 1, dig_fp)) {
	return -1;
    }

    if (cats->n_cats > 0) {
	if (Map->head.Version_Minor == 1) {	/* coor format 5.1 */
	    if (0 >= dig__fwrite_port_I(&(cats->n_cats), 1, dig_fp))
		return -1;
	}
	else {			/* coor format 5.0 */
	    nc = (char)cats->n_cats;
	    if (0 >= dig__fwrite_port_C(&nc, 1, dig_fp))
		return -1;
	}

	if (cats->n_cats > 0) {
	    if (Map->head.Version_Minor == 1) {	/* coor format 5.1 */
		if (0 >=
		    dig__fwrite_port_I(cats->field, cats->n_cats, dig_fp))
		    return -1;
	    }
	    else {		/* coor format 5.0 */
		for (i = 0; i < cats->n_cats; i++) {
		    field = (short)cats->field[i];
		    if (0 >= dig__fwrite_port_S(&field, 1, dig_fp))
			return -1;
		}
	    }
	    if (0 >= dig__fwrite_port_I(cats->cat, cats->n_cats, dig_fp))
		return -1;
	}
    }

    if (type & GV_POINTS) {
	n_points = 1;
    }
    else {
	n_points = points->n_points;
	if (0 >= dig__fwrite_port_I(&n_points, 1, dig_fp))
	    return -1;
    }

    if (0 >= dig__fwrite_port_D(points->x, n_points, dig_fp))
	return -1;
    if (0 >= dig__fwrite_port_D(points->y, n_points, dig_fp))
	return -1;

    if (Map->head.with_z) {
	if (0 >= dig__fwrite_port_D(points->z, n_points, dig_fp))
	    return -1;
    }

    if (0 != dig_fflush(dig_fp))
	return -1;

    return offset;
}

/*!
  \brief Deletes feature at the given offset (level 1)
  
  \param Map pointer Map_info structure
  \param offset feature offset
  
  \return  0 on success
  \return -1 on error
*/
int V1_delete_line_nat(struct Map_info *Map, off_t offset)
{
    char rhead;
    struct gvfile *dig_fp;

    G_debug(3, "V1_delete_line_nat(), offset = %lu", (unsigned long) offset);

    dig_set_cur_port(&(Map->head.port));
    dig_fp = &(Map->dig_fp);

    if (dig_fseek(dig_fp, offset, 0) == -1)
	return -1;

    /* read old */
    if (0 >= dig__fread_port_C(&rhead, 1, dig_fp))
	return (-1);

    rhead &= 0xFE;

    if (dig_fseek(dig_fp, offset, 0) == -1)
	return -1;

    if (0 >= dig__fwrite_port_C(&rhead, 1, dig_fp))
	return -1;

    if (0 != dig_fflush(dig_fp))
	return -1;

    return 0;
}

/*!
  \brief Deletes feature (topology level).
  
  \param pointer to Map_info structure
  \param line feature id
  
  \return 0 on success
  \return -1 on error
*/
int V2_delete_line_nat(struct Map_info *Map, int line)
{
    return V2__delete_line(Map, line, V1_delete_line_nat);
}

/*!
  \brief Restores feature at the given offset.
  
  \param Map pointer to Map_info structure
  \param offset feature offset
  
  \return  0 on success
  \return -1 on error
*/
int V1_restore_line_nat(struct Map_info *Map, off_t offset)
{
    char rhead;
    struct gvfile *dig_fp;
    
    G_debug(3, "V1_restore_line_nat(), offset = %lu", (unsigned long) offset);
    
    dig_set_cur_port(&(Map->head.port));
    dig_fp = &(Map->dig_fp);
    
    if (dig_fseek(dig_fp, offset, 0) == -1)
	return -1;
    
    /* read old */
    if (0 >= dig__fread_port_C(&rhead, 1, dig_fp))
	return (-1);

    /* mark as alive */
    rhead |= 1;
    
    /* write new */
    if (dig_fseek(dig_fp, offset, 0) == -1)
	return -1;

    if (0 >= dig__fwrite_port_C(&rhead, 1, dig_fp))
	return -1;
    
    if (0 != dig_fflush(dig_fp))
	return -1;
    
    return 0;
}

/*!
  \brief Restores feature (topology level)
  
  \param Map pointer to Map_info structure
  \param line feature id
  \param offset feature offset
  
  \return 0 on success
  \return -1 on error
*/
int V2_restore_line_nat(struct Map_info *Map, int line, off_t offset)
{
    int i, ret, type;
    struct P_line *Line;
    struct Plus_head *plus;
    struct bound_box box;
    
    static struct line_pnts *points = NULL;
    static struct line_cats *cats = NULL;
    
    Line = NULL;
    type = 0;
    
    G_debug(3, "V2_restore_line_nat(), line = %d", line);

    plus = &(Map->plus);

    if (plus->built >= GV_BUILD_BASE) {
	Line = Map->plus.Line[line];

	if (Line != NULL)
	    G_fatal_error(_("Attempt to restore alive feature"));
    }

    if (!points) {
	points = Vect_new_line_struct();
    }

    if (!cats) {
	cats = Vect_new_cats_struct();
    }

    /* restore the line in coor */
    ret = V1_restore_line_nat(Map, offset);

    if (ret == -1) {
	return ret;
    }
    
    /* read feature geometry */
    type = V1_read_line_nat(Map, points, cats, offset);
    if (type < 0) {
	return -1;
    }

    /* update category index */
    if (plus->update_cidx) {
	for (i = 0; i < cats->n_cats; i++) {
	    dig_cidx_add_cat(plus, cats->field[i], cats->cat[i], line, type);
	}
    }
    
    /* restore the line from topo */		   
    if (plus->built >= GV_BUILD_BASE) {
	dig_restore_line(plus, line, type, points, offset);
	G_debug(3, "  line restored in topo with id = %d", line);
	dig_line_box(points, &box);
	dig_line_set_box(plus, line, &box);
	Vect_box_extend(&(plus->box), &box);
    }
    
    Vect__add_line_to_topo(Map,
		     line, points, cats);

    G_debug(3, "updated lines : %d , updated nodes : %d", plus->n_uplines,
	    plus->n_upnodes);
    

    return ret;
}