StackOverflow2013

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copied!<p>I guess <strong>Hot Licks</strong> is right, you probably want to simply use <code>-[NSData dataWithContentsOfFile:]</code>, but in the case you want to use C level APIs, you can do:</p> <pre><code>#define MY_BUFFER_SIZE 1024 FILE * fd = fopen(c_sd_url, "rb"); NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; char buffer[MY_BUFFER_SIZE]; if (fd) { fcntl(fd, F_GLOBAL_NOCACHE, 1); // if you can predict the capacity it's better for performance NSMutableData* myData = [NSMutableData dataWithCapacity:1024]; while(fgets(buffer, MY_BUFFER_SIZE, fd) != NULL) { [myData appendBytes:buffer length:strlen(buffer)]; } } // use your 'myData' [pool release]; </code></pre> <p><strong>Updated:</strong> to avoid useless copy of <code>buffer</code> data, and following <strong>H2CO3</strong>'s comment:</p> <p>It's better to avoid to write data to a buffer and then copy it to the NSMutableData, we can use <code>-[NSData mutableBytes]</code> to access directly the underlying C structure. Also, <strong>H2CO3</strong> is completely right, using <code>fread</code> is much better since it gives us the length of the bytes read.</p> <pre><code>#define MY_BUFFER_SIZE 1024 FILE * fd = fopen(c_sd_url, "rb"); if (fd) { fcntl(fd, F_GLOBAL_NOCACHE, 1); // if you can predict the capacity it's better for performance NSMutableData* myData = [[NSMutableData alloc] init]; while(YES) { // store the length before addition NSUInteger previousLength = [myData length]; // increase the length so we can write more bytes [myData increaseLengthBy:MY_BUFFER_SIZE]; // read bytes from stream directly at the end of our data size_t len = fread([myData mutableBytes] + previousLength, 1, MY_BUFFER_SIZE, fd); // set data length [myData setLength:previousLength + len]; // if end-of-file exit the loop if (len == 0) { break; } } // use your 'myData' NSLog(@"myData: %@", [[NSString alloc] initWithData:myData encoding:NSASCIIStringEncoding]); [myData release]; } </code></pre> <p>If you want to have a <code>\0</code> terminated NSData, just add at the end:</p> <pre><code>[myData appendBytes:"\0" length:1]; </code></pre> <p>Good luck ;)</p>

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