Added BasicFile::StreamFile helper function to support reading large files in a chunked fashion (will be using memory-mapped strategy in the future where it makes sense)

1 files changed, 23 insertions, 0 deletions

diff --git a/zenstore/basicfile.cpp b/zenstore/basicfile.cpp
index 75de638cf..126f2a8b3 100644
--- a/zenstore/basicfile.cpp
+++ b/zenstore/basicfile.cpp
@@ -96,6 +96,29 @@ BasicFile::ReadAll()
 }
 
 void
+BasicFile::StreamFile(std::function<void(const void* Data, uint64_t Size)>&& ChunkFun)
+{
+	const uint64_t ChunkSize = 128 * 1024;
+	IoBuffer	   ReadBuffer{ChunkSize};
+	void*		   BufferPtr = ReadBuffer.MutableData();
+
+	uint64_t RemainBytes   = FileSize();
+	uint64_t CurrentOffset = 0;
+
+	while (RemainBytes)
+	{
+		const uint64_t ThisChunkBytes = zen::Min(ChunkSize, RemainBytes);
+
+		Read(BufferPtr, ThisChunkBytes, CurrentOffset);
+
+		ChunkFun(BufferPtr, ThisChunkBytes);
+
+		CurrentOffset += ThisChunkBytes;
+		RemainBytes -= ThisChunkBytes;
+	}
+}
+
+void
 BasicFile::Write(const void* Data, uint64_t Size, uint64_t Offset)
 {
 	OVERLAPPED Ovl{};