Question

Please any one guide me how to create bytes array from nsdata here is my code for createing nsdata

NSData* data = UIImagePNGRepresentation(img);

Answer 1

If you only want to read them, there’s a really easy method :

unsigned char *bytes = [data bytes];

If you want to edit the data, there’s a method on NSData that does this.

// Make your array to hold the bytes
NSUInteger length = [data length];
unsigned char *bytes = malloc( length * sizeof(unsigned char) );

// Get the data
[data getBytes:bytes length:length];

NB Don’t forget – if you’re copying the data, you also have to call free(bytes) at some point 😉