Custom blob subtypes

Support for custom blob subtypes added.

Blob subtypes supported now:
- 1: TEXT
- 0: binary
- <= -1: custom

Issue #146

rsfbclient-native/src/row.rs

@@ -76,16 +76,17 @@ impl ColumnBuffer {
                 Boolean(Box::new(0))
             }
 
-            // BLOB sql_type text are considered a normal text on read
-            ibase::SQL_BLOB if (sqlsubtype == 0 || sqlsubtype == 1) => {
+            ibase::SQL_BLOB if (sqlsubtype <= 1) => {
                 let blob_id = Box::new(ibase::GDS_QUAD_t {
                     gds_quad_high: 0,
                     gds_quad_low: 0,
                 });
 
                 var.sqltype = ibase::SQL_BLOB as i16 + 1;
 
-                if sqlsubtype == 0 {
+                // subtype 0: binary
+                // subtype <= -1: custom
+                if sqlsubtype <= 0 {
                     BlobBinary(blob_id)
                 } else {
                     BlobText(blob_id)

rsfbclient-rust/src/xsqlda.rs

@@ -96,7 +96,7 @@ impl XSqlVar {
                 self.sqltype = ibase::SQL_TIMESTAMP as i16 + 1;
             }
 
-            ibase::SQL_BLOB if (sqlsubtype == 0 || sqlsubtype == 1) => {
+            ibase::SQL_BLOB if (sqlsubtype <= 1) => {
                 self.sqltype = ibase::SQL_BLOB as i16 + 1;
             }
 

src/tests/row.rs

@@ -202,6 +202,18 @@ mk_tests_default! {
         Ok(())
     }
 
+    #[test]
+    fn blob_custom_subtype() -> Result<(), FbError> {
+        let mut conn = cbuilder().connect()?;
+
+        let (a,): (Option<Vec<u8>>,) = conn.query_first("select cast(null as blob SUB_TYPE -1) from rdb$database;", ())?
+            .unwrap();
+
+        assert_eq!(None, a);
+
+        Ok(())
+    }
+
     #[test]
     fn dates() -> Result<(), FbError> {
         let mut conn = cbuilder().connect()?;