3 files changed, 28 insertions, 18 deletions

diff --git a/src/crc.rs b/src/crc.rs
index cfcf982..6219e8c 100644
--- a/src/crc.rs
+++ b/src/crc.rs
@@ -1,23 +1,25 @@
 // Copyright 2019 Robin Krahl <robin.krahl@ireas.org>
 // SPDX-License-Identifier: GPL-3.0-or-later
 
+use core::iter::Iterator;
+
 use hal::stm32::CRC;
 
-pub struct Crc {
+pub trait Crc {
+    fn get(&self, data: &[u8]) -> u32 {
+        self.get_u32(data.chunks(4).map(slice_to_u32))
+    }
+
+    fn get_u32<I: Iterator<Item = u32>>(&self, iter: I) -> u32;
+}
+
+pub struct Stm32Crc {
     crc: CRC,
 }
 
-impl Crc {
+impl Stm32Crc {
     pub fn new(crc: CRC) -> Self {
-        Crc { crc }
-    }
-
-    pub fn get(&self, data: &[u8]) -> u32 {
-        self.reset();
-        data.chunks(4)
-            .map(slice_to_u32)
-            .for_each(|val| self.write(val));
-        self.read()
+        Self { crc }
     }
 
     fn write(&self, val: u32) {
@@ -33,6 +35,14 @@ impl Crc {
     }
 }
 
+impl Crc for Stm32Crc {
+    fn get_u32<I: Iterator<Item = u32>>(&self, iter: I) -> u32 {
+        self.reset();
+        iter.for_each(|val| self.write(val));
+        self.read()
+    }
+}
+
 fn slice_to_u32(data: &[u8]) -> u32 {
     data.iter()
         .enumerate()
diff --git a/src/device.rs b/src/device.rs
index 9f3d1a7..830fa93 100644
--- a/src/device.rs
+++ b/src/device.rs
@@ -94,15 +94,15 @@ impl Response {
     }
 }
 
-pub struct Nitrokey {
-    crc: Crc,
+pub struct Nitrokey<C: Crc> {
+    crc: C,
     request: Option<Request>,
     request_crc: u32,
     buf: [u8; REPORT_LEN],
 }
 
-impl Nitrokey {
-    pub fn new(crc: Crc) -> Self {
+impl<C: Crc> Nitrokey<C> {
+    pub fn new(crc: C) -> Self {
         Nitrokey {
             crc,
             request: None,
@@ -112,7 +112,7 @@ impl Nitrokey {
     }
 }
 
-impl HidDevice for Nitrokey {
+impl<C: Crc> HidDevice for Nitrokey<C> {
     fn subclass(&self) -> Subclass {
         Subclass::BootInterface
     }
diff --git a/src/main.rs b/src/main.rs
index 7e364ab..eb01dd6 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -19,7 +19,7 @@ use hal::prelude::*;
 use stm32f103xx_usb::UsbBus;
 use usb_device::class::UsbClass;
 
-use crate::crc::Crc;
+use crate::crc::Stm32Crc;
 use crate::device::Nitrokey;
 use crate::hid::HidClass;
 
@@ -28,7 +28,7 @@ fn main() -> ! {
     let p = hal::stm32::Peripherals::take().unwrap();
 
     p.RCC.ahbenr.modify(|_, w| w.crcen().set_bit());
-    let crc = Crc::new(p.CRC);
+    let crc = Stm32Crc::new(p.CRC);
 
     let mut flash = p.FLASH.constrain();
     let mut rcc = p.RCC.constrain();