1 files changed, 39 insertions, 0 deletions
diff --git a/openssl/src/memcmp.rs b/openssl/src/memcmp.rs
new file mode 100644
index 00000000..0a7124bd
--- /dev/null
+++ b/openssl/src/memcmp.rs
@@ -0,0 +1,39 @@
+use libc::size_t;
+use ffi;
+
+/// Returns `true` iff `a` and `b` contain the same bytes.
+///
+/// This operation takes an amount of time dependent on the length of the two
+/// arrays given, but is independent of the contents of a and b.
+///
+/// # Panics
+///
+/// This function will panic the current task if `a` and `b` do not have the same
+/// length.
+pub fn eq(a: &[u8], b: &[u8]) -> bool {
+    assert!(a.len() == b.len());
+    let ret = unsafe {
+        ffi::CRYPTO_memcmp(a.as_ptr() as *const _,
+                           b.as_ptr() as *const _,
+                           a.len() as size_t)
+    };
+    ret == 0
+}
+
+#[cfg(test)]
+mod tests {
+    use super::eq;
+
+    #[test]
+    fn test_eq() {
+        assert!(eq(&[], &[]));
+        assert!(eq(&[1], &[1]));
+        assert!(!eq(&[1, 2, 3], &[1, 2, 4]));
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_diff_lens() {
+        eq(&[], &[1]);
+    }
+}