1 files changed, 58 insertions, 0 deletions
diff --git a/vendor/gix-index/src/extension/iter.rs b/vendor/gix-index/src/extension/iter.rs
new file mode 100644
index 000000000..f791b064e
--- /dev/null
+++ b/vendor/gix-index/src/extension/iter.rs
@@ -0,0 +1,58 @@
+use std::convert::TryInto;
+
+use crate::{extension, extension::Iter, util::from_be_u32};
+
+impl<'a> Iter<'a> {
+    /// Create a new extension iterator at the entrypoint for extensions until the end of the extensions.
+    pub fn new(data_at_beginning_of_extensions_and_truncated: &'a [u8]) -> Self {
+        Iter {
+            data: data_at_beginning_of_extensions_and_truncated,
+            consumed: 0,
+        }
+    }
+
+    /// Create a new iterator at with a data block to the end of the file, and we automatically remove the trailing
+    /// hash of type `object_hash`.
+    pub fn new_without_checksum(
+        data_at_beginning_of_extensions: &'a [u8],
+        object_hash: gix_hash::Kind,
+    ) -> Option<Self> {
+        let end = data_at_beginning_of_extensions
+            .len()
+            .checked_sub(object_hash.len_in_bytes())?;
+        Iter {
+            data: &data_at_beginning_of_extensions[..end],
+            consumed: 0,
+        }
+        .into()
+    }
+}
+
+impl<'a> Iterator for Iter<'a> {
+    type Item = (extension::Signature, &'a [u8]);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.data.len() < 4 + 4 {
+            return None;
+        }
+
+        let (signature, data) = self.data.split_at(4);
+        let (size, data) = data.split_at(4);
+        self.data = data;
+        self.consumed += 4 + 4;
+
+        let size = from_be_u32(size) as usize;
+
+        match data.get(..size) {
+            Some(ext_data) => {
+                self.data = &data[size..];
+                self.consumed += size;
+                Some((signature.try_into().unwrap(), ext_data))
+            }
+            None => {
+                self.data = &[];
+                None
+            }
+        }
+    }
+}