data: Added sdb_data_isnull().

The function determines if a datum pointer or a string or binary datum is
NULL.

diff --git a/src/core/data.c b/src/core/data.c
index a57c8c6affc739a2e95bad3c0bd9dc08442c5088..eeead556899382b1e78270714a3e69eadc349129 100644 (file)
--- a/src/core/data.c
+++ b/src/core/data.c
@@ -334,6 +334,18 @@ sdb_data_cmp(const sdb_data_t *d1, const sdb_data_t *d2)
 #undef CMP_NULL
 } /* sdb_data_cmp */
 
+_Bool
+sdb_data_isnull(const sdb_data_t *datum)
+{
+       if (! datum)
+               return 1;
+       if ((datum->type == SDB_TYPE_STRING) && (! datum->data.string))
+               return 1;
+       if ((datum->type == SDB_TYPE_BINARY) && (! datum->data.binary.datum))
+               return 1;
+       return 0;
+} /* sdb_data_isnull */
+
 int
 sdb_data_expr_eval(int op, const sdb_data_t *d1, const sdb_data_t *d2,
                sdb_data_t *res)

diff --git a/src/include/core/data.h b/src/include/core/data.h
index 02f99c5313ebc33ce18a6826cd33740ec364802a..af4ae5abb7e0d6f25c83e2d7856f90b9b17cd9ee 100644 (file)
--- a/src/include/core/data.h
+++ b/src/include/core/data.h
@@ -115,6 +115,14 @@ sdb_data_free_datum(sdb_data_t *datum);
 int
 sdb_data_cmp(const sdb_data_t *d1, const sdb_data_t *d2);
 
+/*
+ * sdb_data_isnull:
+ * Determine whether a datum is NULL. A datum is considered to be NULL if
+ * either datum is NULL or if the string or binary datum is NULL.
+ */
+_Bool
+sdb_data_isnull(const sdb_data_t *datum);
+
 /*
  * Operators supported by sdb_data_eval_expr.
  */