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/**********************************************************************
* $Id: lwmline.c 9324 2012-02-27 22:08:12Z pramsey $
*
* PostGIS - Spatial Types for PostgreSQL
* http://postgis.refractions.net
* Copyright 2001-2006 Refractions Research Inc.
*
* This is free software; you can redistribute and/or modify it under
* the terms of the GNU General Public Licence. See the COPYING file.
*
**********************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "liblwgeom_internal.h"
void
lwmline_release(LWMLINE *lwmline)
{
lwgeom_release(lwmline_as_lwgeom(lwmline));
}
LWMLINE *
lwmline_construct_empty(int srid, char hasz, char hasm)
{
LWMLINE *ret = (LWMLINE*)lwcollection_construct_empty(MULTILINETYPE, srid, hasz, hasm);
return ret;
}
LWMLINE* lwmline_add_lwline(LWMLINE *mobj, const LWLINE *obj)
{
return (LWMLINE*)lwcollection_add_lwgeom((LWCOLLECTION*)mobj, (LWGEOM*)obj);
}
/**
* Re-write the measure ordinate (or add one, if it isn't already there) interpolating
* the measure between the supplied start and end values.
*/
LWMLINE*
lwmline_measured_from_lwmline(const LWMLINE *lwmline, double m_start, double m_end)
{
int i = 0;
int hasm = 0, hasz = 0;
double length = 0.0, length_so_far = 0.0;
double m_range = m_end - m_start;
LWGEOM **geoms = NULL;
if ( lwmline->type != MULTILINETYPE )
{
lwerror("lwmline_measured_from_lmwline: only multiline types supported");
return NULL;
}
hasz = FLAGS_GET_Z(lwmline->flags);
hasm = 1;
/* Calculate the total length of the mline */
for ( i = 0; i < lwmline->ngeoms; i++ )
{
LWLINE *lwline = (LWLINE*)lwmline->geoms[i];
if ( lwline->points && lwline->points->npoints > 1 )
{
length += ptarray_length_2d(lwline->points);
}
}
if ( lwgeom_is_empty((LWGEOM*)lwmline) )
{
return (LWMLINE*)lwcollection_construct_empty(MULTILINETYPE, lwmline->srid, hasz, hasm);
}
geoms = lwalloc(sizeof(LWGEOM*) * lwmline->ngeoms);
for ( i = 0; i < lwmline->ngeoms; i++ )
{
double sub_m_start, sub_m_end;
double sub_length = 0.0;
LWLINE *lwline = (LWLINE*)lwmline->geoms[i];
if ( lwline->points && lwline->points->npoints > 1 )
{
sub_length = ptarray_length_2d(lwline->points);
}
sub_m_start = (m_start + m_range * length_so_far / length);
sub_m_end = (m_start + m_range * (length_so_far + sub_length) / length);
geoms[i] = (LWGEOM*)lwline_measured_from_lwline(lwline, sub_m_start, sub_m_end);
length_so_far += sub_length;
}
return (LWMLINE*)lwcollection_construct(lwmline->type, lwmline->srid, NULL, lwmline->ngeoms, geoms);
}
void lwmline_free(LWMLINE *mline)
{
int i;
if ( ! mline ) return;
if ( mline->bbox )
lwfree(mline->bbox);
for ( i = 0; i < mline->ngeoms; i++ )
if ( mline->geoms && mline->geoms[i] )
lwline_free(mline->geoms[i]);
if ( mline->geoms )
lwfree(mline->geoms);
lwfree(mline);
}
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