openpgp: Rework Bitfield::padding_len.

4 files changed, 7 insertions, 16 deletions

diff --git a/openpgp/src/types/bitfield.rs b/openpgp/src/types/bitfield.rs
index af05d24f..ea0c7c21 100644
--- a/openpgp/src/types/bitfield.rs
+++ b/openpgp/src/types/bitfield.rs
@@ -35,16 +35,10 @@ impl Bitfield {
             .filter_map(|(i, v)| if v { Some(i) } else { None })
     }
 
-    pub fn padding_len(&self) -> usize {
-        let mut padding = 0;
-        for i in (0..self.raw.len()).rev() {
-            if self.raw[i] == 0 {
-                padding += 1;
-            } else {
-                break;
-            }
-        }
-        padding
+    /// Returns the number of trailing zero bytes.
+    pub fn padding_bytes(&self) -> Option<std::num::NonZeroUsize> {
+        std::num::NonZeroUsize::new(
+            self.raw.iter().rev().take_while(|b| **b == 0).count())
     }
 
     /// Compares two feature sets for semantic equality.
diff --git a/openpgp/src/types/features.rs b/openpgp/src/types/features.rs
index 2a3689ce..29fb8560 100644
--- a/openpgp/src/types/features.rs
+++ b/openpgp/src/types/features.rs
@@ -85,8 +85,7 @@ impl fmt::Debug for Features {
         }
 
         // Mention any padding, as equality is sensitive to this.
-        let padding = self.0.padding_len();
-        if padding > 0 {
+        if let Some(padding) = self.0.padding_bytes() {
             if need_comma { f.write_str(", ")?; }
             write!(f, "+padding({} bytes)", padding)?;
         }
diff --git a/openpgp/src/types/key_flags.rs b/openpgp/src/types/key_flags.rs
index 5c3a8945..e2948722 100644
--- a/openpgp/src/types/key_flags.rs
+++ b/openpgp/src/types/key_flags.rs
@@ -95,8 +95,7 @@ impl fmt::Debug for KeyFlags {
         }
 
         // Mention any padding, as equality is sensitive to this.
-        let padding = self.0.padding_len();
-        if padding > 0 {
+        if let Some(padding) = self.0.padding_bytes() {
             if need_comma { f.write_str(", ")?; }
             write!(f, "+padding({} bytes)", padding)?;
         }
diff --git a/openpgp/src/types/server_preferences.rs b/openpgp/src/types/server_preferences.rs
index cd3d10aa..6428196f 100644
--- a/openpgp/src/types/server_preferences.rs
+++ b/openpgp/src/types/server_preferences.rs
@@ -78,8 +78,7 @@ impl fmt::Debug for KeyServerPreferences {
         }
 
         // Mention any padding, as equality is sensitive to this.
-        let padding = self.0.padding_len();
-        if padding > 0 {
+        if let Some(padding) = self.0.padding_bytes() {
             if need_comma { f.write_str(", ")?; }
             write!(f, "+padding({} bytes)", padding)?;
         }