Rename to shared-brotli-patch-decoder and add a basic README.

googlefonts · Oct 4, 2024 · d0021c8 · d0021c8
1 parent 1bfb66b
commit d0021c8
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Showing 4 changed files with 19 additions and 25 deletions.
diff --git a/Cargo.toml b/Cargo.toml
@@ -12,7 +12,7 @@ members = [
     "fauntlet",
     "klippa",
     "fuzz",
-    "shared-brotli",
+    "shared-brotli-patch-decoder",
 ]
 
 [workspace.package]
@@ -45,7 +45,7 @@ read-fonts = { version = "0.22.3", path = "read-fonts", default-features = false
 # shaping support
 skrifa = { version = "0.22.3", path = "skrifa", default-features = false, features = ["std"] }
 write-fonts = { version = "0.29.0", path = "write-fonts" }
-shared-brotli = { version = "0.1.0", path = "shared-brotli" }
+shared-brotli-patch-decoder = { version = "0.1.0", path = "shared-brotli-patch-decoder" }
 
 [workspace.metadata.release]
 allow-branch = ["main"]
diff --git a/shared-brotli/Cargo.toml → shared-brotli-patch-decoder/Cargo.toml b/shared-brotli/Cargo.toml → shared-brotli-patch-decoder/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
-name = "shared-brotli"
+name = "shared-brotli-patch-decoder"
 version = "0.1.0"
-description = "Wrapper around brotli-sys which allows for decoding shared brotli (https://datatracker.ietf.org/doc/draft-vandevenne-shared-brotli-format/) encoded data."
+description = "Wrapper around brotli-sys which allows for decoding shared brotli (https://datatracker.ietf.org/doc/draft-vandevenne-shared-brotli-format/) encoded patch data."
 edition.workspace = true
 license.workspace = true
 repository.workspace = true

diff --git a/shared-brotli-patch-decoder/README.md b/shared-brotli-patch-decoder/README.md
@@ -0,0 +1,6 @@
+# Shared Brotli Patch Decoder
+
+This crate provides a wrapper around brotlic-sys to provide a method for decoding brotli encoded data which utilizes a shared raw
+LZ77 dictionary. This is an extension to standard brotli decoding, which is specified here: https://datatracker.ietf.org/doc/html/draft-vandevenne-shared-brotli-format-11#section-3.2
+
+This is meant to primarily be used in the context of decoding incremental font transfer patches (see: https://w3c.github.io/IFT/Overview.html#table-keyed).
diff --git a/shared-brotli/src/lib.rs → shared-brotli-patch-decoder/src/lib.rs b/shared-brotli/src/lib.rs → shared-brotli-patch-decoder/src/lib.rs
@@ -46,7 +46,7 @@ impl std::error::Error for DecodeError {}
 pub fn shared_brotli_decode(
     encoded: &[u8],
     shared_dictionary: Option<&[u8]>,
-    max_uncompressed_length: u32,
+    max_uncompressed_length: usize,
 ) -> Result<Vec<u8>, DecodeError> {
     let decoder = unsafe { BrotliDecoderCreateInstance(None, None, ptr::null_mut()) };
     if decoder.is_null() {
@@ -70,7 +70,7 @@ pub fn shared_brotli_decode(
         }
     }
 
-    let mut sink = vec![0u8; max_uncompressed_length as usize];
+    let mut sink = vec![0u8; max_uncompressed_length];
 
     let mut next_in = encoded.as_ptr();
     let mut available_in = encoded.len();
@@ -159,11 +159,7 @@ mod tests {
     fn brotli_decode_with_shared_dict() {
         assert_eq!(
             Ok(TARGET.to_vec()),
-            shared_brotli_decode(
-                &SHARED_DICT_PATCH,
-                Some(BASE.as_bytes()),
-                TARGET.len() as u32,
-            )
+            shared_brotli_decode(&SHARED_DICT_PATCH, Some(BASE.as_bytes()), TARGET.len(),)
         );
     }
 
@@ -173,37 +169,29 @@ mod tests {
 
         assert_eq!(
             Ok(TARGET.to_vec()),
-            shared_brotli_decode(&NO_DICT_PATCH, None, TARGET.len() as u32)
+            shared_brotli_decode(&NO_DICT_PATCH, None, TARGET.len())
         );
 
         // Check that empty base is handled the same as no base.
         assert_eq!(
             Ok(TARGET.to_vec()),
-            shared_brotli_decode(&NO_DICT_PATCH, Some(base), TARGET.len() as u32)
+            shared_brotli_decode(&NO_DICT_PATCH, Some(base), TARGET.len())
         );
     }
 
     #[test]
     fn brotli_decode_too_little_output() {
         assert_eq!(
             Err(DecodeError::MaxSizeExceeded),
-            shared_brotli_decode(
-                &SHARED_DICT_PATCH,
-                Some(BASE.as_bytes()),
-                (TARGET.len() - 1) as u32
-            )
+            shared_brotli_decode(&SHARED_DICT_PATCH, Some(BASE.as_bytes()), TARGET.len() - 1)
         );
     }
 
     #[test]
     fn brotli_decode_excess_output() {
         assert_eq!(
             Ok(TARGET.to_vec()),
-            shared_brotli_decode(
-                &SHARED_DICT_PATCH,
-                Some(BASE.as_bytes()),
-                (TARGET.len() + 1) as u32,
-            )
+            shared_brotli_decode(&SHARED_DICT_PATCH, Some(BASE.as_bytes()), TARGET.len() + 1,)
         );
     }
 
@@ -214,7 +202,7 @@ mod tests {
 
         assert_eq!(
             Err(DecodeError::ExcessInputData),
-            shared_brotli_decode(&patch, None, TARGET.len() as u32)
+            shared_brotli_decode(&patch, None, TARGET.len())
         );
     }
 
@@ -224,7 +212,7 @@ mod tests {
         let patch: Vec<u8> = NO_DICT_PATCH[..NO_DICT_PATCH.len() - 1].to_vec();
         assert_eq!(
             Err(DecodeError::InvalidStream),
-            shared_brotli_decode(&patch, None, TARGET.len() as u32)
+            shared_brotli_decode(&patch, None, TARGET.len())
         );
     }