Revert check_disk performance data back to used space (#2243)

* Implement simple output shortcut for ranges

If ranges start with zero (e.g. 0:10), the zero and the colon
can be left out.

This patch implements this by default, since some systems (icinga2)
do not fully implement the whole range format and this reduces errors
in the common case of just an upper border.

* switch check_disk perfdata back to used space

1 files changed, 10 insertions, 1 deletions

diff --git a/lib/perfdata.c b/lib/perfdata.c
index f4eaf843..e3710ec7 100644
--- a/lib/perfdata.c
+++ b/lib/perfdata.c
@@ -251,7 +251,16 @@ char *mp_range_to_string(const mp_range input) {
         if (input.start_infinity) {
                 asprintf(&result, "%s~:", result);
         } else {
-                asprintf(&result, "%s%s:", result, pd_value_to_string(input.start));
+                // check for zeroes, so we can use the short form
+                if ((input.start.type == PD_TYPE_NONE) ||
+                     ((input.start.type == PD_TYPE_INT) && (input.start.pd_int == 0)) ||
+                     ((input.start.type == PD_TYPE_UINT) && (input.start.pd_uint == 0)) ||
+                     ((input.start.type == PD_TYPE_DOUBLE) && (input.start.pd_double == 0))){
+                        // nothing to do here
+                } else {
+                        // Start value is an actual value
+                        asprintf(&result, "%s%s:", result, pd_value_to_string(input.start));
+                }
         }
 
         if (!input.end_infinity) {