1 files changed, 79 insertions, 0 deletions
diff --git a/web/api/queries/median/median.c b/web/api/queries/median/median.c
new file mode 100644
index 000000000..5a13b2e4d
--- /dev/null
+++ b/web/api/queries/median/median.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "median.h"
+
+
+// ----------------------------------------------------------------------------
+// median
+
+struct grouping_median {
+    size_t series_size;
+    size_t next_pos;
+
+    LONG_DOUBLE series[];
+};
+
+void *grouping_create_median(RRDR *r) {
+    long entries = r->group;
+    if(entries < 0) entries = 0;
+
+    struct grouping_median *g = (struct grouping_median *)callocz(1, sizeof(struct grouping_median) + entries * sizeof(LONG_DOUBLE));
+    g->series_size = (size_t)entries;
+
+    return g;
+}
+
+// resets when switches dimensions
+// so, clear everything to restart
+void grouping_reset_median(RRDR *r) {
+    struct grouping_median *g = (struct grouping_median *)r->internal.grouping_data;
+    g->next_pos = 0;
+}
+
+void grouping_free_median(RRDR *r) {
+    freez(r->internal.grouping_data);
+    r->internal.grouping_data = NULL;
+}
+
+void grouping_add_median(RRDR *r, calculated_number value) {
+    struct grouping_median *g = (struct grouping_median *)r->internal.grouping_data;
+
+    if(unlikely(g->next_pos >= g->series_size)) {
+        error("INTERNAL ERROR: median buffer overflow on chart '%s' - next_pos = %zu, series_size = %zu, r->group = %ld.", r->st->name, g->next_pos, g->series_size, r->group);
+    }
+    else {
+        if(isnormal(value))
+            g->series[g->next_pos++] = (LONG_DOUBLE)value;
+    }
+}
+
+calculated_number grouping_flush_median(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr) {
+    struct grouping_median *g = (struct grouping_median *)r->internal.grouping_data;
+
+    calculated_number value;
+
+    if(unlikely(!g->next_pos)) {
+        value = 0.0;
+        *rrdr_value_options_ptr |= RRDR_VALUE_EMPTY;
+    }
+    else {
+        if(g->next_pos > 1) {
+            sort_series(g->series, g->next_pos);
+            value = (calculated_number)median_on_sorted_series(g->series, g->next_pos);
+        }
+        else
+            value = (calculated_number)g->series[0];
+
+        if(!isnormal(value)) {
+            value = 0.0;
+            *rrdr_value_options_ptr |= RRDR_VALUE_EMPTY;
+        }
+
+        //log_series_to_stderr(g->series, g->next_pos, value, "median");
+    }
+
+    g->next_pos = 0;
+
+    return value;
+}
+