refactor sha1 to allow passing in an initial state

2 files changed, 18 insertions, 10 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 8452240..112f968 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -28,6 +28,8 @@ pub use primitives::repeating_key_xor;
 pub use random::MersenneTwister;
 pub use random::mt19937_stream_cipher;
 pub use sha1::sha1;
+pub use sha1::pad_sha1;
+pub use sha1::sha1_with_state;
 pub use sha1::sha1_mac;
 pub use crack::BlockCipherMode;
 pub use crack::find_aes_128_ecb_encrypted_string;
diff --git a/src/sha1.rs b/src/sha1.rs
index 3e97478..bb6d82c 100644
--- a/src/sha1.rs
+++ b/src/sha1.rs
@@ -1,29 +1,35 @@
 #[cfg(test)] use serialize::hex::ToHex;
 
 pub fn sha1 (bytes: &[u8]) -> [u8; 20] {
-    let mut h: [u32; 5] = [
-        0x67452301,
-        0xEFCDAB89,
-        0x98BADCFE,
-        0x10325476,
-        0xC3D2E1F0,
-    ];
+    sha1_with_state(
+        bytes,
+        [
+            0x67452301,
+            0xEFCDAB89,
+            0x98BADCFE,
+            0x10325476,
+            0xC3D2E1F0,
+        ]
+    )
+}
 
+pub fn pad_sha1 (bytes: &[u8]) -> Vec<u8> {
     let ml: u64 = bytes.len() as u64 * 8;
     let ml_bytes: [u8; 8] = unsafe {
         ::std::mem::transmute(ml.to_be())
     };
 
-    let message: Vec<u8> = bytes
+    return bytes
         .iter()
         .map(|x| *x)
         .chain(::std::iter::repeat(0x80).take(1))
         .chain(::std::iter::repeat(0x00).take(55 - (bytes.len() % 64)))
         .chain(ml_bytes.iter().map(|x| *x))
         .collect();
-    assert!(message.len() % 64 == 0);
+}
 
-    for chunk in message.chunks(64) {
+pub fn sha1_with_state (bytes: &[u8], mut h: [u32; 5]) -> [u8; 20] {
+    for chunk in pad_sha1(bytes).chunks(64) {
         let chunk_words: &[u32; 16] = unsafe {
             ::std::mem::transmute(chunk.as_ptr())
         };