optimizations (#200)

* Use direct file read and direct buffer allocation for small IoBuffer materalization
* Reduce range of materialized data in CompositeBuffer reading
CompressedBuffer header reading often only need a small part and not the whole file
* reduce lock contention in IoBuffer::Materialize
* Reduce parsing of compressed headers
Validate header type at decompression
* faster CreateDirectories - start from leaf going up and recurse back
* optimized BufferHeader::IsValid
* Add ValidateCompressedHeader to use when we don't need the actual compressed data
Validate that we always get compressed data in CidStore::AddChunk
* changelog

1 files changed, 5 insertions, 5 deletions

diff --git a/zenstore/filecas.cpp b/zenstore/filecas.cpp
index 38d7898cf..e67653e8a 100644
--- a/zenstore/filecas.cpp
+++ b/zenstore/filecas.cpp
@@ -519,9 +519,7 @@ FileCasStrategy::InsertChunk(const void* const ChunkData, const size_t ChunkSize
 	if (hRes == HRESULT_FROM_WIN32(ERROR_PATH_NOT_FOUND))
 	{
 		// Ensure parent directories exist and retry file creation
-
-		std::filesystem::create_directories(std::wstring_view(Name.ShardedPath.c_str(), Name.Shard2len));
-
+		CreateDirectories(std::wstring_view(Name.ShardedPath.c_str(), Name.Shard2len));
 		hRes = InternalCreateFile();
 	}
 
@@ -789,9 +787,11 @@ FileCasStrategy::Scrub(ScrubContext& Ctx)
 		ChunkBytes += Payload.FileSize();
 
 		IoBuffer Buffer(IoBuffer::BorrowedFile, Payload.Handle(), 0, Payload.FileSize());
-		if (CompressedBuffer Compressed = CompressedBuffer::FromCompressed(SharedBuffer(Buffer)); Compressed)
+		IoHash	 RawHash;
+		uint64_t RawSize;
+		if (CompressedBuffer::ValidateCompressedHeader(Buffer, RawHash, RawSize))
 		{
-			if (IoHash::FromBLAKE3(Compressed.GetRawHash()) != Hash)
+			if (RawHash != Hash)
 			{
 				// Hash mismatch
 				BadHashes.push_back(Hash);