format: slice entry points for the facade's hot *_in calls (local listing back to main's speed)

Since the M2 merge the facade handed in-memory files to the generic
`*_in` parsers as `&[u8]` (`with_bytes!`), which instantiates them in
the facade crate, where the format crate's private helpers do not
inline without LTO: listing a 400-group v1 file through `File::open`
was 7-10% slower than main. `ObjectHeader::parse_in`,
`group_v2::{resolve_child_in, resolve_group_children_in,
resolve_path_any_in}` and `attribute::{extract_attributes_tolerant_in,
find_attribute_in}` now pass a storage with `as_contiguous()` to their
non-generic slice entry point, compiled once in the format crate; other
storages reach the same generic core as before.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

crates/clawhdf5-format/src/group_v2.rs

@@ -368,15 +368,30 @@ pub fn resolve_child(
     group_address: u64,
     name: &str,
 ) -> Result<u64, FormatError> {
-    resolve_child_in(file_data, superblock, group_address, name)
+    resolve_child_core(file_data, superblock, group_address, name)
 }
 
-/// [`resolve_child`] over any [`Storage`].
+/// [`resolve_child`] over any [`Storage`]. One with the whole file in memory
+/// is read as the slice, by code compiled in this crate (see
+/// [`crate::storage`], "Slice entry points").
+#[inline]
 pub fn resolve_child_in<S: Storage + ?Sized>(
     file_data: &S,
     superblock: &Superblock,
     group_address: u64,
     name: &str,
+) -> Result<u64, FormatError> {
+    match file_data.as_contiguous() {
+        Some(all) => resolve_child(all, superblock, group_address, name),
+        None => resolve_child_core(file_data, superblock, group_address, name),
+    }
+}
+
+fn resolve_child_core<S: Storage + ?Sized>(
+    file_data: &S,
+    superblock: &Superblock,
+    group_address: u64,
+    name: &str,
 ) -> Result<u64, FormatError> {
     let os = superblock.offset_size;
     let ls = superblock.length_size;
@@ -453,14 +468,28 @@ pub fn resolve_path_any(
     superblock: &Superblock,
     path: &str,
 ) -> Result<u64, FormatError> {
-    resolve_path_any_in(file_data, superblock, path)
+    resolve_path_any_core(file_data, superblock, path)
 }
 
-/// [`resolve_path_any`] over any [`Storage`].
+/// [`resolve_path_any`] over any [`Storage`]. One with the whole file in memory
+/// is read as the slice, by code compiled in this crate (see
+/// [`crate::storage`], "Slice entry points").
+#[inline]
 pub fn resolve_path_any_in<S: Storage + ?Sized>(
     file_data: &S,
     superblock: &Superblock,
     path: &str,
+) -> Result<u64, FormatError> {
+    match file_data.as_contiguous() {
+        Some(all) => resolve_path_any(all, superblock, path),
+        None => resolve_path_any_core(file_data, superblock, path),
+    }
+}
+
+fn resolve_path_any_core<S: Storage + ?Sized>(
+    file_data: &S,
+    superblock: &Superblock,
+    path: &str,
 ) -> Result<u64, FormatError> {
     resolve_path_following_links(
         file_data,
@@ -513,14 +542,28 @@ pub fn resolve_group_children(
     superblock: &Superblock,
     group_address: u64,
 ) -> Result<Vec<GroupEntry>, FormatError> {
-    resolve_group_children_in(file_data, superblock, group_address)
+    resolve_group_children_core(file_data, superblock, group_address)
 }
 
-/// [`resolve_group_children`] over any [`Storage`].
+/// [`resolve_group_children`] over any [`Storage`]. One with the whole file in memory
+/// is read as the slice, by code compiled in this crate (see
+/// [`crate::storage`], "Slice entry points").
+#[inline]
 pub fn resolve_group_children_in<S: Storage + ?Sized>(
     file_data: &S,
     superblock: &Superblock,
     group_address: u64,
+) -> Result<Vec<GroupEntry>, FormatError> {
+    match file_data.as_contiguous() {
+        Some(all) => resolve_group_children(all, superblock, group_address),
+        None => resolve_group_children_core(file_data, superblock, group_address),
+    }
+}
+
+fn resolve_group_children_core<S: Storage + ?Sized>(
+    file_data: &S,
+    superblock: &Superblock,
+    group_address: u64,
 ) -> Result<Vec<GroupEntry>, FormatError> {
     let os = superblock.offset_size;
     let ls = superblock.length_size;