int main(void) {
int total_tuples = 23;
int i;
int ret;
char *err_msg = NULL;
int start_vertex = 4401489;
int end_vertex = 4401483;
int v_min_id = LONG_MAX;
int v_max_id = 0;
int s_count = 0;
int t_count = 0;
path_element_t *path = NULL;
int path_count = 0;
for (i=0; i<total_tuples; i++) {
if(edges[i].source < v_min_id) v_min_id = edges[i].source;
if(edges[i].target < v_min_id) v_min_id = edges[i].target;
if(edges[i].source > v_max_id) v_max_id = edges[i].source;
if(edges[i].target > v_max_id) v_max_id = edges[i].target;
}
printf("%i <-> %i\n", v_min_id, v_max_id);
for (i=0; i<total_tuples; i++) {
if (edges[i].source == start_vertex || edges[i].target == start_vertex)
s_count++;
if (edges[i].source == end_vertex || edges[i].target == end_vertex)
t_count++;
edges[i].source -= v_min_id;
edges[i].target -= v_min_id;
}
assert(s_count);
assert(t_count);
start_vertex -= v_min_id;
end_vertex -= v_min_id;
ret = boost_dijkstra(edges, total_tuples, start_vertex, end_vertex,
0, 0, &path, &path_count, &err_msg);
if (ret < 0) {
printf("Error computing path: %s\n", err_msg);
exit(1);
}
printf(" seq: vertex_id, edge_id, cost\n");
for (i=0; i<path_count; i++) {
path[i].vertex_id += v_min_id;
printf("%6d: %10d, %10d, %10.4f\n", i, path[i].vertex_id, path[i].edge_id, path[i].cost);
}
if (path) free(path);
exit(0);
}
static int compute_shortest_path(char* sql, int start_vertex,
int end_vertex, bool directed,
bool has_reverse_cost,
path_element_t **path, int *path_count)
{
int SPIcode;
void *SPIplan;
Portal SPIportal;
bool moredata = TRUE;
int ntuples;
edge_t *edges = NULL;
int total_tuples = 0;
edge_columns_t edge_columns = {id: -1, source: -1, target: -1,
cost: -1, reverse_cost: -1};
int v_max_id=0;
int v_min_id=INT_MAX;
int s_count = 0;
int t_count = 0;
char *err_msg;
int ret = -1;
register int z;
DBG("start shortest_path\n");
SPIcode = SPI_connect();
if (SPIcode != SPI_OK_CONNECT)
{
elog(ERROR, "shortest_path: couldn't open a connection to SPI");
return -1;
}
SPIplan = SPI_prepare(sql, 0, NULL);
if (SPIplan == NULL)
{
elog(ERROR, "shortest_path: couldn't create query plan via SPI");
return -1;
}
if ((SPIportal = SPI_cursor_open(NULL, SPIplan, NULL, NULL, true)) == NULL)
{
elog(ERROR, "shortest_path: SPI_cursor_open('%s') returns NULL", sql);
return -1;
}
while (moredata == TRUE)
{
SPI_cursor_fetch(SPIportal, TRUE, TUPLIMIT);
if (edge_columns.id == -1)
{
if (fetch_edge_columns(SPI_tuptable, &edge_columns,
has_reverse_cost) == -1)
return finish(SPIcode, ret);
}
ntuples = SPI_processed;
total_tuples += ntuples;
if (!edges)
edges = palloc(total_tuples * sizeof(edge_t));
else
edges = repalloc(edges, total_tuples * sizeof(edge_t));
if (edges == NULL)
{
elog(ERROR, "Out of memory");
return finish(SPIcode, ret);
}
if (ntuples > 0)
{
int t;
SPITupleTable *tuptable = SPI_tuptable;
TupleDesc tupdesc = SPI_tuptable->tupdesc;
for (t = 0; t < ntuples; t++)
{
HeapTuple tuple = tuptable->vals[t];
fetch_edge(&tuple, &tupdesc, &edge_columns,
&edges[total_tuples - ntuples + t]);
}
SPI_freetuptable(tuptable);
}
else
{
moredata = FALSE;
}
}
//defining min and max vertex id
DBG("Total %i tuples", total_tuples);
for(z=0; z<total_tuples; z++)
{
if(edges[z].source<v_min_id)
v_min_id=edges[z].source;
if(edges[z].source>v_max_id)
v_max_id=edges[z].source;
if(edges[z].target<v_min_id)
v_min_id=edges[z].target;
if(edges[z].target>v_max_id)
v_max_id=edges[z].target;
DBG("%i <-> %i", v_min_id, v_max_id);
}
//::::::::::::::::::::::::::::::::::::
//:: reducing vertex id (renumbering)
//::::::::::::::::::::::::::::::::::::
for(z=0; z<total_tuples; z++)
{
//check if edges[] contains source and target
if(edges[z].source == start_vertex || edges[z].target == start_vertex)
++s_count;
if(edges[z].source == end_vertex || edges[z].target == end_vertex)
++t_count;
edges[z].source-=v_min_id;
edges[z].target-=v_min_id;
DBG("%i - %i", edges[z].source, edges[z].target);
}
DBG("Total %i tuples", total_tuples);
if(s_count == 0)
{
elog(ERROR, "Source vertex: %d was not found as vertex of any of the input edges.", start_vertex);
return -1;
}
if(t_count == 0)
{
elog(ERROR, "Target vertex: %d was not found as vertex of any of the input edges.", end_vertex);
return -1;
}
DBG("Calling boost_dijkstra\n");
start_vertex -= v_min_id;
end_vertex -= v_min_id;
ret = boost_dijkstra(edges, total_tuples, start_vertex, end_vertex,
directed, has_reverse_cost,
path, path_count, &err_msg);
DBG("SIZE %i\n",*path_count);
//::::::::::::::::::::::::::::::::
//:: restoring original vertex id
//::::::::::::::::::::::::::::::::
for(z=0;z<*path_count;z++)
{
//DBG("vetex %i\n",(*path)[z].vertex_id);
(*path)[z].vertex_id+=v_min_id;
}
DBG("ret = %i\n", ret);
DBG("*path_count = %i\n", *path_count);
DBG("ret = %i\n", ret);
if (ret < 0)
{
//elog(ERROR, "Error computing path: %s", err_msg);
ereport(ERROR, (errcode(ERRCODE_E_R_E_CONTAINING_SQL_NOT_PERMITTED),
errmsg("Error computing path: %s", err_msg)));
}
if (edges) {
/* clean up input egdes */
pfree (edges);
}
return finish(SPIcode, ret);
}
PG_FUNCTION_INFO_V1(shortest_path);
Datum
shortest_path(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
int call_cntr;
int max_calls;
TupleDesc tuple_desc;
path_element_t *path = NULL;
char *sql = NULL;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
MemoryContext oldcontext;
int path_count = 0;
int ret;
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/* switch to memory context appropriate for multiple function calls */
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* edge sql query */
sql = text2char(PG_GETARG_TEXT_P(0));
ret = compute_shortest_path(sql,
PG_GETARG_INT32(1),
PG_GETARG_INT32(2),
PG_GETARG_BOOL(3),
PG_GETARG_BOOL(4), &path, &path_count);
/* clean up sql query string */
if (sql) {
pfree (sql);
}
#ifdef DEBUG
DBG("Ret is %i", ret);
if (ret >= 0)
{
int i;
for (i = 0; i < path_count; i++)
{
DBG("Step %i vertex_id %i ", i, path[i].vertex_id);
DBG(" edge_id %i ", path[i].edge_id);
DBG(" cost %f ", path[i].cost);
}
}
#endif
/* total number of tuples to be returned */
funcctx->max_calls = path_count;
funcctx->user_fctx = path;
funcctx->tuple_desc =
BlessTupleDesc(RelationNameGetTupleDesc("path_result"));
MemoryContextSwitchTo(oldcontext);
}
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
call_cntr = funcctx->call_cntr;
max_calls = funcctx->max_calls;
tuple_desc = funcctx->tuple_desc;
path = (path_element_t*) funcctx->user_fctx;
if (call_cntr < max_calls) /* do when there is more left to send */
{
HeapTuple tuple;
Datum result;
Datum *values;
char* nulls;
/* This will work for some compilers. If it crashes with segfault, try to change the following block with this one
values = palloc(4 * sizeof(Datum));
nulls = palloc(4 * sizeof(char));
values[0] = call_cntr;
nulls[0] = ' ';
values[1] = Int32GetDatum(path[call_cntr].vertex_id);
nulls[1] = ' ';
values[2] = Int32GetDatum(path[call_cntr].edge_id);
nulls[2] = ' ';
values[3] = Float8GetDatum(path[call_cntr].cost);
nulls[3] = ' ';
*/
values = palloc(3 * sizeof(Datum));
nulls = palloc(3 * sizeof(char));
values[0] = Int32GetDatum(path[call_cntr].vertex_id);
nulls[0] = ' ';
values[1] = Int32GetDatum(path[call_cntr].edge_id);
nulls[1] = ' ';
values[2] = Float8GetDatum(path[call_cntr].cost);
nulls[2] = ' ';
tuple = heap_formtuple(tuple_desc, values, nulls);
/* make the tuple into a datum */
result = HeapTupleGetDatum(tuple);
/* clean up (this is not really necessary) */
pfree(values);
pfree(nulls);
SRF_RETURN_NEXT(funcctx, result);
}
else /* do when there is no more left */
{
if (path) {
/* clean up returned edge paths
must be a free because it's malloc'd */
free (path);
path = NULL;
}
SRF_RETURN_DONE(funcctx);
}
}
