MakeFromFile() on POSIX

1 files changed, 43 insertions, 23 deletions

diff --git a/zencore/iobuffer.cpp b/zencore/iobuffer.cpp
index 2473e0530..16b530955 100644
--- a/zencore/iobuffer.cpp
+++ b/zencore/iobuffer.cpp
@@ -15,6 +15,7 @@
 #if ZEN_PLATFORM_WINDOWS
 #	include <atlfile.h>
 #else
+#	include <sys/stat.h>
 #	include <sys/mman.h>
 #endif
 
@@ -352,42 +353,61 @@ IoBufferBuilder::MakeFromFileHandle(void* FileHandle, uint64_t Offset, uint64_t
 IoBuffer
 IoBufferBuilder::MakeFromFile(const path_char_t* FileName, uint64_t Offset, uint64_t Size)
 {
+	uint64_t FileSize;
+
+#if ZEN_PLATFORM_WINDOWS
 	CAtlFile DataFile;
 
 	HRESULT hRes = DataFile.Create(FileName, GENERIC_READ, FILE_SHARE_READ, OPEN_EXISTING);
 
-	if (SUCCEEDED(hRes))
+	if (FAILED(hRes))
 	{
-		ULONGLONG FileSize;
-		DataFile.GetSize(FileSize);
+		return {};
+	}
 
-		// TODO: should validate that offset is in range
+	DataFile.GetSize((ULONGLONG&)FileSize);
+#else
+	int Fd = open(FileName, O_RDONLY);
+	if (Fd < 0)
+	{
+		return {};
+	}
+
+	static_assert(sizeof(decltype(stat::st_size)) == sizeof(uint64_t), "fstat() doesn't support large files");
+	struct stat Stat;
+	fstat(Fd, &Stat);
+	FileSize = Stat.st_size;
+#endif // ZEN_PLATFORM_WINDOWS
+
+	// TODO: should validate that offset is in range
 
-		if (Size == ~0ull)
+	if (Size == ~0ull)
+	{
+		Size = FileSize - Offset;
+	}
+	else
+	{
+		// Clamp size
+		if ((Offset + Size) > FileSize)
 		{
 			Size = FileSize - Offset;
 		}
-		else
-		{
-			// Clamp size
-			if ((Offset + Size) > FileSize)
-			{
-				Size = FileSize - Offset;
-			}
-		}
+	}
 
-		if (Size)
-		{
-			return IoBuffer(IoBuffer::File, DataFile.Detach(), Offset, Size);
-		}
-		else
-		{
-			// For an empty file, we may as well just return an empty memory IoBuffer
-			return IoBuffer(IoBuffer::Wrap, "", 0);
-		}
+	if (Size)
+	{
+#if ZEN_PLATFORM_WINDOWS
+		void* Fd = DataFile.Detach();
+#endif
+		return IoBuffer(IoBuffer::File, (void*)uintptr_t(Fd), Offset, Size);
 	}
 
-	return {};
+#if !ZEN_PLATFORM_WINDOWS
+	close(Fd);
+#endif
+
+	// For an empty file, we may as well just return an empty memory IoBuffer
+	return IoBuffer(IoBuffer::Wrap, "", 0);
 }
 
 IoBuffer