objective-c - iOS Nsdata (hexadecimal stored in it) converted to decimal

Question

NSdata header stores the length of the image, ru: <00000000 000768f3 >, this is a hexadecimal number, how to convert it to decimal

Answer 1

uint64_t length = 0;
[data getBytes:&length length:8];
length = CFSwapInt64HostToBig(length);