CData: Added support for undefined values.

NaN will be treated as undefined value.

diff --git a/src/cdata.c b/src/cdata.c
index 2630e733d35d10200e9938adc5082ff6bc200ea2..418ec0afa2fe42f3068584cb0551964b70527f0e 100644 (file)
--- a/src/cdata.c
+++ b/src/cdata.c
@@ -33,6 +33,7 @@
 
 #include <errno.h>
 #include <string.h>
+#include <math.h>
 
 #include <postgres.h>
 #include <fmgr.h>
@@ -153,6 +154,10 @@ cdata_in(PG_FUNCTION_ARGS)
        data->value   = strtod(val_str, &endptr);
        data->val_num = 1;
 
+       if (isnan(data->value)) {
+               data->undef_num = 1;
+       }
+
        if ((endptr == val_str) || errno)
                ereport(ERROR, (
                                        errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
@@ -358,6 +363,12 @@ cdata_update(PG_FUNCTION_ARGS)
        cdata_t *data;
        cdata_t *update;
 
+       float8 value;
+       float8 u_value;
+
+       int32 val_num;
+       int32 u_val_num;
+
        if (PG_NARGS() != 2)
                ereport(ERROR, (
                                        errmsg("cdata_update() expects two arguments"),
@@ -380,20 +391,30 @@ cdata_update(PG_FUNCTION_ARGS)
                                                "consolidation function")
                                ));
 
+       value     = data->value;
+       u_value   = update->value;
+
+       val_num   = data->val_num - data->undef_num;
+       u_val_num = update->val_num - update->undef_num;
+
+       data->undef_num += update->undef_num;
+       data->val_num   += update->val_num;
+
+       if (isnan(value) || isnan(u_value)) {
+               data->value = isnan(value) ? u_value : value;
+               PG_RETURN_CDATA_P(data);
+       }
+
        switch (data->cf) {
                case CF_AVG:
-                       data->value = (data->value * (data->val_num - data->undef_num))
-                               + (update->value * (update->val_num - update->undef_num));
-                       data->value /= (data->val_num - data->undef_num)
-                                       +  (update->val_num - update->undef_num);
+                       data->value = ((value * val_num) + (u_value * u_val_num))
+                               / (val_num + u_val_num);
                        break;
                case CF_MIN:
-                       data->value = (data->value <= update->value)
-                               ? data->value : update->value;
+                       data->value = (value < u_value) ? value : u_value;
                        break;
                case CF_MAX:
-                       data->value = (data->value >= update->value)
-                               ? data->value : update->value;
+                       data->value = (value >= u_value) ? value : u_value;
                        break;
                default:
                        ereport(ERROR, (
@@ -403,9 +424,6 @@ cdata_update(PG_FUNCTION_ARGS)
                                        ));
                        break;
        }
-
-       data->undef_num += update->undef_num;
-       data->val_num   += update->val_num;
        PG_RETURN_CDATA_P(data);
 } /* cdata_update */