1 files changed, 14 insertions, 2 deletions
diff --git a/src/bn/mod.rs b/src/bn/mod.rs
index fb836a39..129f6b90 100644
--- a/src/bn/mod.rs
+++ b/src/bn/mod.rs
@@ -1,4 +1,4 @@
-use libc::{c_int, c_ulong};
+use libc::{c_int, c_ulong, c_void};
 use std::{fmt, ptr};
 use std::c_str::CString;
 use std::num::{One, Zero};
@@ -6,6 +6,16 @@ use std::num::{One, Zero};
 use ffi;
 use ssl::error::SslError;
 
+#[allow(dead_code)]
+#[repr(C)]
+pub struct BIGNUM {
+    d: *mut c_void,
+    top: c_int,
+    dmax: c_int,
+    neg: c_int,
+    flags: c_int,
+}
+
 pub struct BigNum(*mut ffi::BIGNUM);
 
 #[repr(C)]
@@ -381,9 +391,11 @@ impl Zero for BigNum {
     fn zero() -> BigNum {
         BigNum::new_from(0).unwrap()
     }
+
     fn is_zero(&self) -> bool {
         unsafe {
-            ffi::BN_is_zero(self.raw()) == 1
+            // It is raw contents of BN_is_zero macro
+            (*self.raw()).top == 0
         }
     }
 }