From 38682821ade69780e5c125fa00f1f71a3b161ffd Mon Sep 17 00:00:00 2001
From: Chris Cole <cjcole@alum.mit.edu>
Date: Sun, 14 Dec 2014 10:02:18 -0500
Subject: [PATCH] Added BigNum::{from_dec_str,from_hex_str}, BN_dec2bn, and
 BN_hex2bn.

---
 openssl-sys/src/lib.rs | 12 +++++++++++-
 src/bn/mod.rs          | 29 +++++++++++++++++++++++++++--
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/openssl-sys/src/lib.rs b/openssl-sys/src/lib.rs
index 03a5a567..68d2d6dc 100644
--- a/openssl-sys/src/lib.rs
+++ b/openssl-sys/src/lib.rs
@@ -81,6 +81,11 @@ pub struct BIGNUM {
     pub flags: c_int,
 }
 
+#[repr(C)]
+pub struct BIGNUM_PTR {
+    pub ptr: *mut BIGNUM,
+}
+
 pub type CRYPTO_EX_new = extern "C" fn(parent: *mut c_void, ptr: *mut c_void,
                                        ad: *const CRYPTO_EX_DATA, idx: c_int,
                                        argl: c_long, argp: *const c_void) -> c_int;
@@ -291,9 +296,14 @@ extern "C" {
     pub fn BN_bin2bn(s: *const u8, size: c_int, ret: *mut BIGNUM) -> *mut BIGNUM;
     pub fn BN_bn2bin(a: *mut BIGNUM, to: *mut u8) -> c_int;
 
-    /* Conversion from/to string representation */
+    /* Conversion from/to decimal string representation */
+    pub fn BN_dec2bn(a: *mut BIGNUM_PTR, s: *const i8) -> c_int;
     pub fn BN_bn2dec(a: *mut BIGNUM) -> *const c_char;
 
+    /* Conversion from/to hexidecimal string representation */
+    pub fn BN_hex2bn(a: *mut BIGNUM_PTR, s: *const i8) -> c_int;
+    pub fn BN_bn2hex(a: *mut BIGNUM) -> *const c_char;
+
     pub fn CRYPTO_num_locks() -> c_int;
     pub fn CRYPTO_set_locking_callback(func: extern "C" fn(mode: c_int,
                                                            n: c_int,
diff --git a/src/bn/mod.rs b/src/bn/mod.rs
index 7f33e9ed..7605fee0 100644
--- a/src/bn/mod.rs
+++ b/src/bn/mod.rs
@@ -84,8 +84,22 @@ impl BigNum {
         })
     }
 
-    pub fn one() -> BigNum {
-        BigNum::new_from(1).unwrap()
+    pub fn from_dec_str(s: &str) -> Result<BigNum, SslError> {
+        BigNum::new().and_then(|v| unsafe {
+            let ref mut bn_ptr = ffi::BIGNUM_PTR { ptr: v.raw(), };
+            let c_str = s.to_c_str();
+            try_ssl!(ffi::BN_dec2bn(bn_ptr, c_str.as_ptr()));
+            Ok(v)
+        })
+    }
+
+    pub fn from_hex_str(s: &str) -> Result<BigNum, SslError> {
+        BigNum::new().and_then(|v| unsafe {
+            let ref mut bn_ptr = ffi::BIGNUM_PTR { ptr: v.raw(), };
+            let c_str = s.to_c_str();
+            try_ssl!(ffi::BN_hex2bn(bn_ptr, c_str.as_ptr()));
+            Ok(v)
+        })
     }
 
     pub fn new_from_slice(n: &[u8]) -> Result<BigNum, SslError> {
@@ -362,6 +376,17 @@ impl BigNum {
             str
         }
     }
+
+    pub fn to_hex_str(&self) -> String {
+        unsafe {
+            let buf = ffi::BN_bn2hex(self.raw());
+            assert!(!buf.is_null());
+            let c_str = CString::new(buf, false);
+            let str = c_str.as_str().unwrap().to_string();
+            ffi::CRYPTO_free(buf as *mut c_void);
+            str
+        }
+    }
 }
 
 impl fmt::Show for BigNum {