fixed a division by zero; added logging in case out of bounds range is selected

diff --git a/src/rrd2json.c b/src/rrd2json.c
index 55fda68d3e61949895c1a6c1d21acbdb062db90c..8969b324b1bf321be020a1569705887295aa4649 100755 (executable)
--- a/src/rrd2json.c
+++ b/src/rrd2json.c
@@ -881,6 +881,7 @@ RRDR *rrd2rrdr(RRDSET *st, long points, long long after, long long before, int g
        // check the wanted points
        if(points < 0) points = -points;
        if(points > available_points) points = available_points;
+       if(points == 0) points = available_points;
 
        // calculate proper grouping of source data
        long group = available_points / points;
@@ -902,6 +903,40 @@ RRDR *rrd2rrdr(RRDSET *st, long points, long long after, long long before, int g
        time_t before_new = rrdset_slot2time(st, start_at_slot);
        long points_new = (before_new - after_new) / st->update_every / group;
 
+       if(after_new < first_entry_t) {
+               error("after_new %u is before min %u", after_new, first_entry_t);
+               after_new = first_entry_t;
+               points_new = (before_new - after_new) / st->update_every / group;
+       }
+       if(after_new > last_entry_t) {
+               error("after_new %u is after max %u", after_new, last_entry_t);
+               after_new = last_entry_t;
+               points_new = (before_new - after_new) / st->update_every / group;
+       }
+       if(before_new < first_entry_t) {
+               error("before_new %u is before min %u", before_new, first_entry_t);
+               before_new = first_entry_t;
+               points_new = (before_new - after_new) / st->update_every / group;
+       }
+       if(before_new > last_entry_t) {
+               error("before_new %u is after max %u", before_new, last_entry_t);
+               before_new = last_entry_t;
+               points_new = (before_new - after_new) / st->update_every / group;
+       }
+       if(start_at_slot < 0 || start_at_slot >= st->entries) {
+               error("start_at_slot is invalid %ld, expected %ld to %ld", start_at_slot, 0, st->entries - 1);
+               start_at_slot = st->current_entry;
+               points_new = (before_new - after_new) / st->update_every / group;
+       }
+       if(stop_at_slot < 0 || stop_at_slot >= st->entries) {
+               error("stop_at_slot is invalid %ld, expected %ld to %ld", stop_at_slot, 0, st->entries - 1);
+               stop_at_slot = 0;
+               points_new = (before_new - after_new) / st->update_every / group;
+       }
+       if(points_new > (before_new - after_new) / group / st->update_every + 1) {
+               error("points_new %ld is more than points %ld", points_new, (before_new - after_new) / group / st->update_every + 1);
+       }
+
        //error("SHIFT: %s: wanted %ld points, got %ld - group=%ld, wanted duration=%u, got %u - wanted %ld - %ld, got %ld - %ld", st->id, points, points_new, group, before - after, before_new - after_new, after, before, after_new, before_new);
 
        after = after_new;