Get CRC checksum of an NSData in Objective-C

Question

How can I count CRC (32 or 64) of an NSData object in Objective-C?

Thanks in advance!

Answer 1

Have a look here for a CRC32 for NSData

http://classroomm.com/objective-c/index.php?action=printpage;topic=2891.0

Answer 2

Use crc32() function from zlib library:

#import <zlib.h>

NSData *data;

// ...

unsigned long result = crc32(0, data.bytes, data.length);
NSLog(@"CRC32: %lu", result);

Make sure to link libz library with your project:

Answer 3

From iOS11 use this:

unsigned long result = crc32_z(0, data.bytes, data.length);