在NSMutableData中插入前面的字节

Question

How can I insert a byte at the beginning of my NSMutableData ? I understand that there is a replaceBytesInRange: method but that will just replace the bytes. There is a bunch of insertXAtIndex: methods but none are for bytes. How can I do this? One way I can think of doing this is:

NSMutableData *theData = [NSMutableData dataWithBytes:myByte];
[theData appendData:myOriginalData];
myOriginalData = nil;

But there must be a better way.

I also tried this but it didn't work:

char *sec = "Second!";
char *fir = "First!";

NSMutableData *theData = [NSMutableData dataWithBytes:(const void *)sec length:7];
[theData replaceBytesInRange:NSMakeRange(0, 0) withBytes:(const void *)fir];

NSString *str1 = [[NSString alloc] initWithData:theData encoding:NSUTF8StringEncoding];
NSLog(@"%@", str1); //Prints "Second!"

Answer 1

[theData replaceBytesInRange:NSMakeRange(0, 0) withBytes:(const void *)fir length:strlen(fir)];

应该做的伎俩。