Edit Question - KnowledgeHub

Title Body

I need to read (scan) a file sequentially and process its content. File size can be anything from very small (some KB) to very large (some GB). I tried two techniques using VC10/VS2010 on Windows 7 64-bit: Win32 memory mapped files (i.e. CreateFile, CreateFileMapping, MapViewOfFile, etc.) fopen and fread from CRT. I thought that memory mapped file technique could be faster than CRT functions, but some tests showed that the speed is almost the same in both cases. The following C++ statements are used for MMF: HANDLE hFile = CreateFile( filename, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_FLAG_SEQUENTIAL_SCAN, NULL ); HANDLE hFileMapping = CreateFileMapping( hFile, NULL, PAGE_READONLY, 0, 0, NULL ); The file is read sequentially, chunk by chunk; each chunk is SYSTEM_INFO.dwAllocationGranularity in size. Considering that speed is almost the same with MMF and CRT, I'd use CRT functions because they are simpler and multi-platform. But I'm curious: am I using the MMF technique correctly? Is it normal that MMF performance in this case of scannig file sequentially is the same as CRT one? Thanks.

Tags (comma-separated) Cancel