Le 8 juin 08 à 20:51, Joan Lluch (casa) a écrit :
El 08/06/2008, a las 20:13, Brent Fulgham escribió:I've been enjoying the NSArray/NSMutableArray classes as I work with various user interface features for a program I'm working on that interacts with a legacy C++ library.I've recently begun considering how to efficiently display the contents of a binary data stream. Currently I'm appending to an NSMutableArray of NSNumber objects, which is great for allowing me to bind to some UI elements in close to real time and has provided a simple and functional mechanism for text numerical display.Ideally, I'd like to be able to access a raw binary buffer of data so I could for example bind it to something like an OpenGL vector buffer for display. However, unlike an STL vector, I don't think the NS[Mutable]Array provides any guarantees of memory organization, nor any way to 'unbox' the NSNumber to deal with the internal values.For example, in the STL, I could make use of the fact that the vector template guarantees the storage to be in contiguous memory and accessible as raw double values through the address of the first element of the vector. However, I don't think this is possible via NSMutableArray and NSNumbers.Is my only option to periodically sync a buffer of binary double values by copying from the NSMutableArray on some periodic basis?Thanks, -BrentSince each item contained in an NSArray is a pointer to an object, you will not be able to retrieve them as raw data of different size even if the pointers in the NSArray were contiguous (which I believe they are)
Assumption are evil. The actual implementation uses a different memory layout for very big arrays. In this special case objects in the array are not in contiguous memory. Anyway this is an implementation details and you should not make any assumption about it.
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