Clippy cleanups (#144)

This updates the clippy::integer_arithmetic to its new name
arithmetic_side_effects and addresses some trivial cases.

ssh-cipher/src/chacha20poly1305.rs

@@ -39,7 +39,7 @@ impl ChaCha20Poly1305 {
     ///
     /// [PROTOCOL.chacha20poly1305]: https://cvsweb.openbsd.org/src/usr.bin/ssh/PROTOCOL.chacha20poly1305?annotate=HEAD
     pub fn new(key: &[u8], nonce: &[u8]) -> Result<Self> {
-        #[allow(clippy::integer_arithmetic)]
+        #[allow(clippy::arithmetic_side_effects)]
         if key.len() != KEY_SIZE * 2 {
             return Err(Error::KeySize);
         }

ssh-cipher/src/lib.rs

@@ -7,7 +7,7 @@
 )]
 #![forbid(unsafe_code)]
 #![warn(
-    clippy::integer_arithmetic,
+    clippy::arithmetic_side_effects,
     clippy::panic,
     clippy::panic_in_result_fn,
     clippy::unwrap_used,
@@ -201,7 +201,7 @@ impl Cipher {
 
     /// Compute the length of padding necessary to pad the given input to
     /// the block size.
-    #[allow(clippy::integer_arithmetic)]
+    #[allow(clippy::arithmetic_side_effects)]
     pub fn padding_len(self, input_size: usize) -> usize {
         match input_size % self.block_size() {
             0 => 0,

ssh-encoding/src/lib.rs

@@ -7,7 +7,7 @@
 )]
 #![forbid(unsafe_code)]
 #![warn(
-    clippy::integer_arithmetic,
+    clippy::arithmetic_side_effects,
     clippy::panic,
     clippy::panic_in_result_fn,
     clippy::unwrap_used,

ssh-key/src/certificate/unix_time.rs

@@ -59,7 +59,7 @@ impl UnixTime {
     }
 
     /// Get the current time as a Unix timestamp.
-    #[cfg(all(feature = "std"))]
+    #[cfg(feature = "std")]
     pub fn now() -> Result<Self> {
         SystemTime::now().try_into()
     }

ssh-key/src/fingerprint/randomart.rs

@@ -12,7 +12,7 @@ use core::fmt;
 const WIDTH: usize = 17;
 const HEIGHT: usize = 9;
 const VALUES: &[u8; 17] = b" .o+=*BOX@%&#/^SE";
-const NVALUES: usize = VALUES.len() - 1;
+const NVALUES: u8 = VALUES.len() as u8 - 1;
 
 type Field = [[u8; WIDTH]; HEIGHT];
 
@@ -25,7 +25,8 @@ pub(super) struct Randomart<'a> {
 
 impl<'a> Randomart<'a> {
     /// Create new "randomart" from the given fingerprint.
-    #[allow(clippy::integer_arithmetic)]
+    // TODO: Remove this when the pipeline toolchain is updated beyond 1.69
+    #[allow(clippy::arithmetic_side_effects)]
     pub(super) fn new(header: &'a str, fingerprint: Fingerprint) -> Self {
         let mut field = Field::default();
         let mut x = WIDTH / 2;
@@ -48,16 +49,16 @@ impl<'a> Randomart<'a> {
                 x = x.min(WIDTH.saturating_sub(1));
                 y = y.min(HEIGHT.saturating_sub(1));
 
-                if field[y][x] < NVALUES as u8 - 2 {
-                    field[y][x] += 1;
+                if field[y][x] < NVALUES - 2 {
+                    field[y][x] = field[y][x].saturating_add(1);
                 }
 
                 byte >>= 2;
             }
         }
 
-        field[HEIGHT / 2][WIDTH / 2] = NVALUES as u8 - 1;
-        field[y][x] = NVALUES as u8;
+        field[HEIGHT / 2][WIDTH / 2] = NVALUES - 1;
+        field[y][x] = NVALUES;
 
         Self {
             header,

ssh-key/src/lib.rs

@@ -7,7 +7,7 @@
 )]
 #![forbid(unsafe_code)]
 #![warn(
-    clippy::integer_arithmetic,
+    clippy::arithmetic_side_effects,
     clippy::mod_module_files,
     clippy::panic,
     clippy::panic_in_result_fn,

ssh-key/src/public/ssh_format.rs

@@ -111,9 +111,7 @@ impl<'a> SshFormat<'a> {
 /// rather than this estimate.
 #[cfg(feature = "alloc")]
 fn base64_len_approx(input_len: usize) -> usize {
-    // TODO(tarcieri): checked arithmetic
-    #[allow(clippy::integer_arithmetic)]
-    ((((input_len * 4) / 3) + 3) & !3)
+    (((input_len.saturating_mul(4)) / 3).saturating_add(3)) & !3
 }
 
 /// Parse a segment of the public key.

ssh-key/src/signature.rs

@@ -414,7 +414,7 @@ impl Verifier<Signature> for public::SkEd25519 {
         let signature_bytes = &signature.as_bytes()[..signature_len];
         let flags_and_counter = &signature.as_bytes()[signature_len..];
 
-        #[allow(clippy::integer_arithmetic)]
+        #[allow(clippy::arithmetic_side_effects)]
         let mut signed_data =
             Vec::with_capacity((2 * Sha256::output_size()) + SK_ED25519_SIGNATURE_TRAILER_SIZE);
         signed_data.extend(Sha256::digest(self.application()));
@@ -451,7 +451,7 @@ impl TryFrom<&p256::ecdsa::Signature> for Signature {
     fn try_from(signature: &p256::ecdsa::Signature) -> Result<Signature> {
         let (r, s) = signature.split_bytes();
 
-        #[allow(clippy::integer_arithmetic)]
+        #[allow(clippy::arithmetic_side_effects)]
         let mut data = Vec::with_capacity(32 * 2 + 4 * 2 + 2);
 
         Mpint::from_positive_bytes(&r)?.encode(&mut data)?;
@@ -473,7 +473,7 @@ impl TryFrom<&p384::ecdsa::Signature> for Signature {
     fn try_from(signature: &p384::ecdsa::Signature) -> Result<Signature> {
         let (r, s) = signature.split_bytes();
 
-        #[allow(clippy::integer_arithmetic)]
+        #[allow(clippy::arithmetic_side_effects)]
         let mut data = Vec::with_capacity(48 * 2 + 4 * 2 + 2);
 
         Mpint::from_positive_bytes(&r)?.encode(&mut data)?;