Make Tag::encoded_length public and prepare for releasing 0.24.0

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "asn1"
-version = "0.23.1"
+version = "0.24.0"
 authors = ["Alex Gaynor <alex.gaynor@gmail.com>"]
 repository = "https://github.com/alex/rust-asn1"
 keywords = ["asn1"]
@@ -17,7 +17,7 @@ default = ["std"]
 std = []
 
 [dependencies]
-asn1_derive = { path = "asn1_derive/", version = "0.23.1" }
+asn1_derive = { path = "asn1_derive/", version = "0.24.0" }
 itoa = "1.0.11"
 
 [dev-dependencies]

README.md

@@ -25,6 +25,17 @@ $ cargo add asn1 --no-default-features
 
 ### Unreleased
 
+### [0.24.0]
+
+#### Added
+
+- `Tag` now exposes an `encoded_length` method that returns the number of
+  bytes needed to encode the tag.
+
+#### Removed
+
+- `Tag::write_to` has been removed from the public API.
+
 ### [0.23.1]
 
 #### Added

asn1_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "asn1_derive"
-version = "0.23.1"
+version = "0.24.0"
 authors = ["Alex Gaynor <alex.gaynor@gmail.com>"]
 repository = "https://github.com/alex/rust-asn1"
 license = "BSD-3-Clause"

asn1parse/Cargo.toml

@@ -7,7 +7,7 @@ publish = false
 rust-version = "1.83.0"
 
 [dependencies]
-asn1 = { version = "0.23.1", path = ".." }
+asn1 = { version = "0.24.0", path = ".." }
 clap = { version = "4.5", features = ["derive"] }
 hex = "0.4.3"
 pem = { version = "3.0.4", default-features = false, features = ["std"] }

src/tag.rs

@@ -107,7 +107,7 @@ impl Tag {
 
     /// Writes the tag's encoded representation (including tag class and
     /// constructed bits) to a `WriteBuf`.
-    pub fn write_to(self, dest: &mut WriteBuf) -> WriteResult {
+    pub(crate) fn write_to(self, dest: &mut WriteBuf) -> WriteResult {
         let mut b = ((self.class as u8) << 6) | if self.constructed { CONSTRUCTED } else { 0 };
         if self.value >= 0x1f {
             b |= 0x1f;
@@ -139,7 +139,7 @@ impl Tag {
     }
 
     /// Get the number of bytes needed to encode this tag.
-    pub(crate) fn encoded_length(self) -> usize {
+    pub fn encoded_length(self) -> usize {
         if self.value >= 0x1f {
             // Long form: 1 byte for the initial tag byte + base128 encoding of the value
             1 + crate::base128::base128_length(self.value.into())
@@ -187,6 +187,28 @@ mod tests {
         assert_eq!(Tag::new(5, TagClass::Application, true).value(), 5);
     }
 
+    #[test]
+    fn test_encoded_length() {
+        // Short form tags (value < 0x1f) should be 1 byte
+        assert_eq!(Tag::new(0, TagClass::Universal, false).encoded_length(), 1);
+        assert_eq!(Tag::new(5, TagClass::Application, true).encoded_length(), 1);
+        assert_eq!(
+            Tag::new(0x1e, TagClass::ContextSpecific, false).encoded_length(),
+            1
+        );
+
+        // Long form tags (value >= 0x1f) should be 1 + base128 length
+        assert_eq!(
+            Tag::new(0x1f, TagClass::Universal, false).encoded_length(),
+            2
+        );
+        assert_eq!(Tag::new(127, TagClass::Private, false).encoded_length(), 2);
+        assert_eq!(
+            Tag::new(128, TagClass::Universal, false).encoded_length(),
+            3
+        );
+    }
+
     #[test]
     fn test_write_to() {
         for (t, expected) in [