add compression_per_level options

src/ffi.rs

@@ -182,6 +182,9 @@ extern "C" {
                                                 cs: DBCompactionStyle);
     pub fn rocksdb_options_set_compression(options: DBOptions,
                                            compression_style_no: DBCompressionType);
+    pub fn rocksdb_options_set_compression_per_level(options: DBOptions,
+                                            level_values: *const DBCompressionType,
+                                            num_levels: size_t);
     pub fn rocksdb_options_set_max_background_compactions(
         options: DBOptions, max_bg_compactions: c_int);
     pub fn rocksdb_options_set_max_background_flushes(options: DBOptions,

src/rocksdb_options.rs

@@ -13,7 +13,7 @@
 // limitations under the License.
 //
 extern crate libc;
-use self::libc::c_int;
+use self::libc::{c_int,size_t};
 use std::ffi::CString;
 use std::mem;
 
@@ -117,6 +117,14 @@ impl Options {
         }
     }
 
+    pub fn compression_per_level(&mut self, level_types: &[DBCompressionType]) {
+        unsafe {
+            rocksdb_ffi::rocksdb_options_set_compression_per_level(self.inner,
+                                                                level_types.as_ptr(),
+                                                                level_types.len() as size_t)
+        }
+    }
+
     pub fn add_merge_operator(&mut self,
                               name: &str,
                               merge_fn: MergeFn) {