int
FindPolygons(SHPObject *obj, Ring ***Out)
{
Ring **Outer; /* Pointers to Outer rings */
int out_index=0; /* Count of Outer rings */
Ring **Inner; /* Pointers to Inner rings */
int in_index=0; /* Count of Inner rings */
int pi; /* part index */
#if POSTGIS_DEBUG_LEVEL > 0
static int call = -1;
call++;
#endif
LWDEBUGF(4, "FindPolygons[%d]: allocated space for %d rings\n", call, obj->nParts);
/* Allocate initial memory */
Outer = (Ring **)malloc(sizeof(Ring *) * obj->nParts);
Inner = (Ring **)malloc(sizeof(Ring *) * obj->nParts);
/* Iterate over rings dividing in Outers and Inners */
for (pi=0; pi < obj->nParts; pi++)
{
int vi; /* vertex index */
int vs; /* start index */
int ve; /* end index */
int nv; /* number of vertex */
double area = 0.0;
Ring *ring;
/* Set start and end vertexes */
if (pi == obj->nParts - 1)
ve = obj->nVertices;
else
ve = obj->panPartStart[pi + 1];
vs = obj->panPartStart[pi];
/* Compute number of vertexes */
nv = ve - vs;
/* Allocate memory for a ring */
ring = (Ring *)malloc(sizeof(Ring));
ring->list = (Point *)malloc(sizeof(Point) * nv);
ring->n = nv;
ring->next = NULL;
ring->linked = 0;
/* Iterate over ring vertexes */
for (vi = vs; vi < ve; vi++)
{
int vn = vi+1; /* next vertex for area */
if (vn == ve)
vn = vs;
ring->list[vi - vs].x = obj->padfX[vi];
ring->list[vi - vs].y = obj->padfY[vi];
ring->list[vi - vs].z = obj->padfZ[vi];
ring->list[vi - vs].m = obj->padfM[vi];
area += (obj->padfX[vi] * obj->padfY[vn]) -
(obj->padfY[vi] * obj->padfX[vn]);
}
/* Close the ring with first vertex */
/*ring->list[vi].x = obj->padfX[vs]; */
/*ring->list[vi].y = obj->padfY[vs]; */
/*ring->list[vi].z = obj->padfZ[vs]; */
/*ring->list[vi].m = obj->padfM[vs]; */
/* Clockwise (or single-part). It's an Outer Ring ! */
if (area < 0.0 || obj->nParts == 1)
{
Outer[out_index] = ring;
out_index++;
}
else
{
/* Counterclockwise. It's an Inner Ring ! */
Inner[in_index] = ring;
in_index++;
}
}
LWDEBUGF(4, "FindPolygons[%d]: found %d Outer, %d Inners\n", call, out_index, in_index);
/* Put the inner rings into the list of the outer rings */
/* of which they are within */
for (pi = 0; pi < in_index; pi++)
{
Point pt, pt2;
int i;
Ring *inner = Inner[pi], *outer = NULL;
pt.x = inner->list[0].x;
pt.y = inner->list[0].y;
pt2.x = inner->list[1].x;
pt2.y = inner->list[1].y;
for (i = 0; i < out_index; i++)
{
int in;
in = PIP(pt, Outer[i]->list, Outer[i]->n);
if ( in || PIP(pt2, Outer[i]->list, Outer[i]->n) )
{
outer = Outer[i];
break;
}
/*fprintf(stderr, "!PIP %s\nOUTE %s\n", dump_ring(inner), dump_ring(Outer[i])); */
}
if (outer)
{
outer->linked++;
while (outer->next)
outer = outer->next;
outer->next = inner;
}
else
{
/* The ring wasn't within any outer rings, */
/* assume it is a new outer ring. */
LWDEBUGF(4, "FindPolygons[%d]: hole %d is orphan\n", call, pi);
Outer[out_index] = inner;
out_index++;
}
}
*Out = Outer;
free(Inner);
return out_index;
}
int
FindPolygons(SHPObject *obj, Ring ***Out)
{
Ring **Outer; /* Pointers to Outer rings */
int out_index=0; /* Count of Outer rings */
Ring **Inner; /* Pointers to Inner rings */
int in_index=0; /* Count of Inner rings */
int pi; /* part index */
#if POSTGIS_DEBUG_LEVEL > 0
static int call = -1;
call++;
#endif
LWDEBUGF(4, "FindPolygons[%d]: allocated space for %d rings\n", call, obj->nParts);
/* Allocate initial memory */
Outer = (Ring **)malloc(sizeof(Ring *) * obj->nParts);
Inner = (Ring **)malloc(sizeof(Ring *) * obj->nParts);
/* Iterate over rings dividing in Outers and Inners */
for (pi=0; pi < obj->nParts; pi++)
{
int vi; /* vertex index */
int vs; /* start index */
int ve; /* end index */
int nv; /* number of vertex */
double area = 0.0;
Ring *ring;
/* Set start and end vertexes */
if (pi == obj->nParts - 1)
ve = obj->nVertices;
else
ve = obj->panPartStart[pi + 1];
vs = obj->panPartStart[pi];
/* Compute number of vertexes */
nv = ve - vs;
/* Allocate memory for a ring */
ring = (Ring *)malloc(sizeof(Ring));
ring->list = (Point *)malloc(sizeof(Point) * nv);
ring->n = nv;
ring->next = NULL;
ring->linked = 0;
/* Iterate over ring vertexes */
for (vi = vs; vi < ve; vi++)
{
int vn = vi+1; /* next vertex for area */
if (vn == ve)
vn = vs;
ring->list[vi - vs].x = obj->padfX[vi];
ring->list[vi - vs].y = obj->padfY[vi];
ring->list[vi - vs].z = obj->padfZ[vi];
ring->list[vi - vs].m = obj->padfM[vi];
area += (obj->padfX[vi] * obj->padfY[vn]) -
(obj->padfY[vi] * obj->padfX[vn]);
}
/* Close the ring with first vertex */
/*ring->list[vi].x = obj->padfX[vs]; */
/*ring->list[vi].y = obj->padfY[vs]; */
/*ring->list[vi].z = obj->padfZ[vs]; */
/*ring->list[vi].m = obj->padfM[vs]; */
/* Clockwise (or single-part). It's an Outer Ring ! */
if (area < 0.0 || obj->nParts == 1)
{
Outer[out_index] = ring;
out_index++;
}
else
{
/* Counterclockwise. It's an Inner Ring ! */
Inner[in_index] = ring;
in_index++;
}
}
LWDEBUGF(4, "FindPolygons[%d]: found %d Outer, %d Inners\n", call, out_index, in_index);
/* Put the inner rings into the list of the outer rings */
/* of which they are within */
for (pi = 0; pi < in_index; pi++)
{
Point pt, pt2;
int i;
Ring *inner = Inner[pi], *outer = NULL;
pt.x = inner->list[0].x;
pt.y = inner->list[0].y;
pt2.x = inner->list[1].x;
pt2.y = inner->list[1].y;
/*
* If we assume that the case of the "big polygon w/o hole
* containing little polygon w/ hold" is ordered so that the
* big polygon comes first, then checking the list in reverse
* will assign the little polygon's hole to the little polygon
* w/o a lot of extra fancy containment logic here
*/
for (i = out_index - 1; i >= 0; i--)
{
int in;
in = PIP(pt, Outer[i]->list, Outer[i]->n);
if ( in || PIP(pt2, Outer[i]->list, Outer[i]->n) )
{
outer = Outer[i];
break;
}
}
if (outer)
{
outer->linked++;
while (outer->next)
outer = outer->next;
outer->next = inner;
}
else
{
/* The ring wasn't within any outer rings, */
/* assume it is a new outer ring. */
LWDEBUGF(4, "FindPolygons[%d]: hole %d is orphan\n", call, pi);
Outer[out_index] = inner;
out_index++;
}
}
*Out = Outer;
/*
* Only free the containing Inner array, not the ring elements, because
* the rings are now owned by the linked lists in the Outer array elements.
*/
free(Inner);
return out_index;
}