LWMPOINT*
lwmpoint_from_lwgeom(const LWGEOM *g)
{
LWPOINTITERATOR* it = lwpointiterator_create(g);
int has_z = lwgeom_has_z(g);
int has_m = lwgeom_has_m(g);
LWMPOINT* result = lwmpoint_construct_empty(g->srid, has_z, has_m);
POINT4D p;
while(lwpointiterator_next(it, &p)) {
LWPOINT* lwp = lwpoint_make(g->srid, has_z, has_m, &p);
lwmpoint_add_lwpoint(result, lwp);
}
lwpointiterator_destroy(it);
return result;
}
LWMPOINT *
lwmpoint_construct(int srid, const POINTARRAY *pa)
{
int i;
int hasz = ptarray_has_z(pa);
int hasm = ptarray_has_m(pa);
LWMPOINT *ret = (LWMPOINT*)lwcollection_construct_empty(MULTIPOINTTYPE, srid, hasz, hasm);
for ( i = 0; i < pa->npoints; i++ )
{
LWPOINT *lwp;
POINT4D p;
getPoint4d_p(pa, i, &p);
lwp = lwpoint_make(srid, hasz, hasm, &p);
lwmpoint_add_lwpoint(ret, lwp);
}
return ret;
}
Datum LWGEOM_dumppoints(PG_FUNCTION_ARGS) {
FuncCallContext *funcctx;
MemoryContext oldcontext, newcontext;
GSERIALIZED *pglwgeom;
LWCOLLECTION *lwcoll;
LWGEOM *lwgeom;
struct dumpstate *state;
struct dumpnode *node;
HeapTuple tuple;
Datum pathpt[2]; /* used to construct the composite return value */
bool isnull[2] = {0,0}; /* needed to say neither value is null */
Datum result; /* the actual composite return value */
if (SRF_IS_FIRSTCALL()) {
funcctx = SRF_FIRSTCALL_INIT();
newcontext = funcctx->multi_call_memory_ctx;
oldcontext = MemoryContextSwitchTo(newcontext);
/* get a local copy of what we're doing a dump points on */
pglwgeom = PG_GETARG_GSERIALIZED_P_COPY(0);
lwgeom = lwgeom_from_gserialized(pglwgeom);
/* return early if nothing to do */
if (!lwgeom || lwgeom_is_empty(lwgeom)) {
MemoryContextSwitchTo(oldcontext);
funcctx = SRF_PERCALL_SETUP();
SRF_RETURN_DONE(funcctx);
}
/* Create function state */
state = lwalloc(sizeof *state);
state->root = lwgeom;
state->stacklen = 0;
state->pathlen = 0;
state->pt = 0;
state->ring = 0;
funcctx->user_fctx = state;
/*
* Push a struct dumpnode on the state stack
*/
state->stack[0].idx = 0;
state->stack[0].geom = lwgeom;
state->stacklen++;
/*
* get tuple description for return type
*/
if (get_call_result_type(fcinfo, 0, &funcctx->tuple_desc) != TYPEFUNC_COMPOSITE) {
ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
}
BlessTupleDesc(funcctx->tuple_desc);
/* get and cache data for constructing int4 arrays */
get_typlenbyvalalign(INT4OID, &state->typlen, &state->byval, &state->align);
MemoryContextSwitchTo(oldcontext);
}
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
newcontext = funcctx->multi_call_memory_ctx;
/* get state */
state = funcctx->user_fctx;
while (1) {
node = &state->stack[state->stacklen-1];
lwgeom = node->geom;
/* need to return a point from this geometry */
if (!lwgeom_is_collection(lwgeom)) {
/* either return a point, or pop the stack */
/* TODO use a union? would save a tiny amount of stack space.
* probably not worth the bother
*/
LWLINE *line;
LWCIRCSTRING *circ;
LWPOLY *poly;
LWTRIANGLE *tri;
LWPOINT *lwpoint = NULL;
POINT4D pt;
/*
* net result of switch should be to set lwpoint to the
* next point to return, or leave at NULL if there
* are no more points in the geometry
*/
switch(lwgeom->type) {
case TRIANGLETYPE:
tri = lwgeom_as_lwtriangle(lwgeom);
if (state->pt == 0) {
state->path[state->pathlen++] = Int32GetDatum(state->ring+1);
}
if (state->pt <= 3) {
getPoint4d_p(tri->points, state->pt, &pt);
lwpoint = lwpoint_make(tri->srid,
FLAGS_GET_Z(tri->points->flags),
FLAGS_GET_M(tri->points->flags),
&pt);
}
if (state->pt > 3) {
state->pathlen--;
}
break;
case POLYGONTYPE:
poly = lwgeom_as_lwpoly(lwgeom);
if (state->pt == poly->rings[state->ring]->npoints) {
state->pt = 0;
state->ring++;
state->pathlen--;
}
if (state->pt == 0 && state->ring < poly->nrings) {
/* handle new ring */
state->path[state->pathlen] = Int32GetDatum(state->ring+1);
state->pathlen++;
}
if (state->ring == poly->nrings) {
} else {
/* TODO should be able to directly get the point
* into the point array of a fixed lwpoint
*/
/* can't get the point directly from the ptarray because
* it might be aligned wrong, so at least one memcpy
* seems unavoidable
* It might be possible to pass it directly to gserialized
* depending how that works, it might effectively be gserialized
* though a brief look at the code indicates not
*/
getPoint4d_p(poly->rings[state->ring], state->pt, &pt);
lwpoint = lwpoint_make(poly->srid,
FLAGS_GET_Z(poly->rings[state->ring]->flags),
FLAGS_GET_M(poly->rings[state->ring]->flags),
&pt);
}
break;
case POINTTYPE:
if (state->pt == 0) lwpoint = lwgeom_as_lwpoint(lwgeom);
break;
case LINETYPE:
line = lwgeom_as_lwline(lwgeom);
if (line->points && state->pt <= line->points->npoints) {
lwpoint = lwline_get_lwpoint((LWLINE*)lwgeom, state->pt);
}
break;
case CIRCSTRINGTYPE:
circ = lwgeom_as_lwcircstring(lwgeom);
if (circ->points && state->pt <= circ->points->npoints) {
lwpoint = lwcircstring_get_lwpoint((LWCIRCSTRING*)lwgeom, state->pt);
}
break;
default:
ereport(ERROR, (errcode(ERRCODE_DATA_EXCEPTION),
errmsg("Invalid Geometry type %d passed to ST_DumpPoints()", lwgeom->type)));
}
/*
* At this point, lwpoint is either NULL, in which case
* we need to pop the geometry stack and get the next
* geometry, if amy, or lwpoint is set and we construct
* a record type with the integer array of geometry
* indexes and the point number, and the actual point
* geometry itself
*/
if (!lwpoint) {
/* no point, so pop the geom and look for more */
if (--state->stacklen == 0) SRF_RETURN_DONE(funcctx);
state->pathlen--;
continue;
} else {
/* write address of current geom/pt */
state->pt++;
state->path[state->pathlen] = Int32GetDatum(state->pt);
pathpt[0] = PointerGetDatum(construct_array(state->path, state->pathlen+1,
INT4OID, state->typlen, state->byval, state->align));
pathpt[1] = PointerGetDatum(gserialized_from_lwgeom((LWGEOM*)lwpoint,0,0));
tuple = heap_form_tuple(funcctx->tuple_desc, pathpt, isnull);
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
}
}
lwcoll = (LWCOLLECTION*)node->geom;
/* if a collection and we have more geoms */
if (node->idx < lwcoll->ngeoms) {
/* push the next geom on the path and the stack */
lwgeom = lwcoll->geoms[node->idx++];
state->path[state->pathlen++] = Int32GetDatum(node->idx);
node = &state->stack[state->stacklen++];
node->idx = 0;
node->geom = lwgeom;
state->pt = 0;
state->ring = 0;
/* loop back to beginning, which will then check whatever node we just pushed */
continue;
}
/* no more geometries in the current collection */
if (--state->stacklen == 0) SRF_RETURN_DONE(funcctx);
state->pathlen--;
state->stack[state->stacklen-1].idx++;
}
}