I create random file:
-(NSData*)generateRandomNSDataWithNumberOfRecords:(int)length {
NSMutableData* theData = [[NSMutableData alloc] init];
int numberOfElements;
for (int i=0; i<length; i++) {
numberOfElements = arc4random() % 15;
if (numberOfElements == 0)
numberOfElements = 1;
NSData *tempData = [NSData dataWithBytes: &numberOfElements length: sizeof(numberOfElements)];
[theData appendData:tempData];
for(int j = 0 ; j < numberOfElements; j++)
{
int randomBits = arc4random()%255; // 0 to 255
[theData appendData:[NSData dataWithBytes: &randomBits length: sizeof(randomBits)]];
}
}
return theData;
}
and when hexdumping it i can see:
hexdump -C Tape1
00000000 04 00 00 00 cd 00 00 00 14 00 00 00 65 00 00 00 |............e...|
00000010 16 00 00 00 0a 00 00 00 d2 00 00 00 c1 00 00 00 |................|
00000020 02 00 00 00 f6 00 00 00 e4 00 00 00 ce 00 00 00 |................|
First one should be 4 (Checked out over debugger). but it appear to be written other way round.
Is there a simple solution to tell NSData to store data "properly"?
It's endian issue.
I just needed to:randomBits = CFSwapInt32HostToBig(randomBits);