memory-mapped-files

问题 I want that a non-.NET application access a Memory Mapped file, but this application is not aware of the existence of Memory Mapped files , so I need the file path. It is possible? 回答1: They have some samples here. EDIT I think this would provide the answer. Basically, it would seem some sort of memory pointer is required for memory-mapped files, and not a file system path. 回答2: You can use the GetMappedFileName function to get the path to a memory mapped file when it is mapped. This of

问题 I'm trying to find out how to remap memory-mapped files on a Mac (when I want to expand the available space). I see our friends in the Linux world have mremap but I can find no such function in the headers on my Mac. /Developer/SDKs/MacOSX10.6.sdk/usr/include/sys/mman.h has the following: mmap mprotect msync munlock munmap but no mremap man mremap confirms my fears. I'm currently having to munmap and mmmap if I want to resize the size of the mapped file, which involves invalidating all the

问题 Is it possible to use numpy.memmap to map a large disk-based array of strings into memory? I know it can be done for floats and suchlike, but this question is specifically about strings. I am interested in solutions for both fixed-length and variable-length strings. The solution is free to dictate any reasonable file format. 回答1: If all the strings have the same length, as suggested by the term "array", this is easily possible: a = numpy.memmap("data", dtype="S10") would be an example for

问题 I am following this tutorial here I am having a hard time figuring out how to get a string "THIS IS A TEST MESSAGE" to store in the memory mapped file and then pull it out on the other side. The tutorial says to use byte array. Forgive me I am new to this and trying on my own first. Thanks, Kevin ##Write to mapped file using System; using System.IO.MemoryMappedFiles; class Program1 { static void Main() { // create a memory-mapped file of length 1000 bytes and give it a 'map name' of 'test'

问题 I am following this tutorial here I am having a hard time figuring out how to get a string "THIS IS A TEST MESSAGE" to store in the memory mapped file and then pull it out on the other side. The tutorial says to use byte array. Forgive me I am new to this and trying on my own first. Thanks, Kevin ##Write to mapped file using System; using System.IO.MemoryMappedFiles; class Program1 { static void Main() { // create a memory-mapped file of length 1000 bytes and give it a 'map name' of 'test'

问题 I have a client/server app. The server component runs, uses WCF in a 'remoting' fashion (binary formatter, session objects). If I start the server component and launch the client, the first task the server does completes in <0.5sec. If I start the server component with VS debugger attached, and then launch the client, the task takes upwards of 20sec to complete. There are no code changes - no conditional compilation changes. The same occurs whether I have the server component compiled and

问题 Is there a way to expand the Java memory-mapped byte buffer such that the new size is reflected back to the mapped file on disk? 回答1: No, you will need to adjust the size of the underlying file and recreate the Memory Mapped Byte Buffer. RandomAccessFile file = new RandomAccessFile(/* some file */); MappedByteBuffer buffer = file.getChannel().map(MapMode.READ_WRITE, 0, file.length()); // Some stuff happens... // adjust the size file.setLength(newLength); // recreate the memory mapped buffer

问题 Scenario I have the following methods: public void AddItemSecurity(int itemId, int[] userIds) public int[] GetValidItemIds(int userId) Initially I'm thinking storage on the form: itemId -> userId, userId, userId and userId -> itemId, itemId, itemId AddItemSecurity is based on how I get data from a third party API, GetValidItemIds is how I want to use it at runtime. There are potentially 2000 users and 10 million items. Item id's are on the form: 2007123456, 2010001234 (10 digits where first

问题 How do you allocate memory that's aligned to a specific boundary in C (e.g., cache line boundary)? I'm looking for malloc/free like implementation that ideally would be as portable as possible --- at least between 32 and 64 bit architectures. Edit to add: In other words, I'm looking for something that would behave like (the now obsolete?) memalign function, which can be freed using free. 回答1: Here is a solution, which encapsulates the call to malloc, allocates a bigger buffer for alignment

问题 I understand how to create a memory mapped file, but my question is let's say that in the following line: FileChannel roChannel = new RandomAccessFile(file, "r").getChannel(); ByteBuffer roBuf = roChannel.map(FileChannel.MapMode.READ_ONLY, 0, SIZE); Where i set SIZE to be 2MB for example, does this means that it will only load 2MB of the file or will it read further in the file and update the buffer as i consume bytes from it? 回答1: Where i set SIZE to be 2MB for example, does this means that