--- /dev/null
+#include "postgres.h"
+#include "fmgr.h"
+#include "utils/elog.h"
+#include "utils/array.h"
+#include "utils/geo_decls.h"
+#include "utils/lsyscache.h"
+#include "catalog/pg_type.h"
+#include "funcapi.h"
+
+#include "liblwgeom.h"
+
+/* ST_DumpPoints for postgis.
+ * By Nathan Wagner, copyright disclaimed,
+ * this entire file is in the public domain
+ */
+
+struct dumpnode {
+ LWGEOM *geom;
+ int idx; /* which member geom we're working on */
+} ;
+
+/* 32 is the max depth for st_dump, so it seems reasonable
+ * to use the same here
+ */
+#define MAXDEPTH 32
+struct dumpstate {
+ LWGEOM *root;
+ int stacklen; /* collections/geoms on stack */
+ int pathlen; /* polygon rings and such need extra path info */
+ struct dumpnode stack[MAXDEPTH];
+ Datum path[34]; /* two more than max depth, for ring and point */
+
+ /* used to cache the type attributes for integer arrays */
+ int16 typlen;
+ bool byval;
+ char align;
+
+ int ring; /* ring of top polygon */
+ int pt; /* point of top geom or current ring */
+};
+
+PG_FUNCTION_INFO_V1(LWGEOM_dumppoints);
+
+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 = (GSERIALIZED *)PG_DETOAST_DATUM_COPY(PG_GETARG_DATUM(0));
+ lwgeom = lwgeom_from_gserialized(pglwgeom);
+
+ /* return early if nothing to do */
+ if (!lwgeom || lwgeom_is_empty(lwgeom)) {
+ 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;
+ 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:
+ case CIRCSTRINGTYPE:
+ line = lwgeom_as_lwline(lwgeom);
+ if (line->points && state->pt <= line->points->npoints) {
+ lwpoint = lwline_get_lwpoint((LWLINE*)lwgeom, state->pt);
+ }
+ break;
+ case CURVEPOLYTYPE:
+ default:
+ /* TODO error? */
+ if (--state->stacklen == 0) SRF_RETURN_DONE(funcctx);
+ state->pathlen--;
+ continue;
+ }
+
+ /*
+ * 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++;
+ }
+}
+
+/*
+ * Geometry types of collection types for reference
+ */
+
+#if 0
+ case MULTIPOINTTYPE:
+ case MULTILINETYPE:
+ case MULTIPOLYGONTYPE:
+ case COLLECTIONTYPE:
+ case CURVEPOLYTYPE:
+ case COMPOUNDTYPE:
+ case MULTICURVETYPE:
+ case MULTISURFACETYPE:
+ case POLYHEDRALSURFACETYPE:
+ case TINTYPE:
+#endif
+
projects / postgis / commitdiff