How to create UUID type 1 in objective C (iOS)

问题:

I created UUID (don't know which type) with the following code:

// Create universally unique identifier (object)
CFUUIDRef uuidObject = CFUUIDCreate(kCFAllocatorDefault);

// Get the string representation of CFUUID object.
NSString *uuidStr = (__bridge NSString *)CFUUIDCreateString(kCFAllocatorDefault, uuidObject);

CFRelease(uuidObject);

But my API that is send data to says that is not type 1 that it needs http://en.wikipedia.org/wiki/Universally_unique_identifier#Version_1_.28MAC_address.29.

How to create this type1 UUID in objC (iphone)?

I have problems making this in obj C, is it an option to use C code to generate this?

回答1:

Get the MAC address first: (from developertips)

#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>

...

- (NSString *)getMacAddress
{
  int                 mgmtInfoBase[6];
  char                *msgBuffer = NULL;
  size_t              length;
  unsigned char       macAddress[6];
  struct if_msghdr    *interfaceMsgStruct;
  struct sockaddr_dl  *socketStruct;
  NSString            *errorFlag = NULL;

  // Setup the management Information Base (mib)
  mgmtInfoBase[0] = CTL_NET;        // Request network subsystem
  mgmtInfoBase[1] = AF_ROUTE;       // Routing table info
  mgmtInfoBase[2] = 0;              
  mgmtInfoBase[3] = AF_LINK;        // Request link layer information
  mgmtInfoBase[4] = NET_RT_IFLIST;  // Request all configured interfaces

  // With all configured interfaces requested, get handle index
  if ((mgmtInfoBase[5] = if_nametoindex("en0")) == 0) 
    errorFlag = @"if_nametoindex failure";
  else
  {
    // Get the size of the data available (store in len)
    if (sysctl(mgmtInfoBase, 6, NULL, &length, NULL, 0) < 0) 
      errorFlag = @"sysctl mgmtInfoBase failure";
    else
    {
      // Alloc memory based on above call
      if ((msgBuffer = malloc(length)) == NULL)
        errorFlag = @"buffer allocation failure";
      else
      {
        // Get system information, store in buffer
        if (sysctl(mgmtInfoBase, 6, msgBuffer, &length, NULL, 0) < 0)
          errorFlag = @"sysctl msgBuffer failure";
      }
    }
  }

  // Befor going any further...
  if (errorFlag != NULL)
  {
    NSLog(@"Error: %@", errorFlag);
    return errorFlag;
  }

  // Map msgbuffer to interface message structure
  interfaceMsgStruct = (struct if_msghdr *) msgBuffer;

  // Map to link-level socket structure
  socketStruct = (struct sockaddr_dl *) (interfaceMsgStruct + 1);

  // Copy link layer address data in socket structure to an array
  memcpy(&macAddress, socketStruct->sdl_data + socketStruct->sdl_nlen, 6);

  // Read from char array into a string object, into traditional Mac address format
  NSString *macAddressString = [NSString stringWithFormat:@"%02X:%02X:%02X:%02X:%02X:%02X", 
                                macAddress[0], macAddress[1], macAddress[2], 
                                macAddress[3], macAddress[4], macAddress[5]];
  NSLog(@"Mac Address: %@", macAddressString);

  // Release the buffer memory
  free(msgBuffer);

  return macAddressString;
}

Then generate the UUIDv1 with the rfc4122 spec, if the spec is too long to read, you may port the code from other language, here's one that I found: https://github.com/fredriklindberg/class.uuid.php/blob/master/class.uuid.php

回答2:

I've been searching for the same thing. Here it is:

uuid_generate_time

https://developer.apple.com/library/ios/documentation/System/Conceptual/ManPages_iPhoneOS/man3/uuid_generate_time.3.html

Also there's Apple source code for this function:

http://www.opensource.apple.com/source/xnu/xnu-792.13.8/libkern/uuid/uuid.c

NSString* uuidString = nil;

// Get UUID type 1

uuid_t dateUUID;
uuid_generate_time(dateUUID);

// Convert it to string

uuid_string_t unparsedUUID;
uuid_unparse_lower(dateUUID, unparsedUUID);
uuidString = [[NSString alloc] initWithUTF8String:unparsedUUID];

回答3:

Using following function you can create dynamic UUID.

-(NSString*)getDynamicUUID 
{
    CFUUIDRef uuidObj = CFUUIDCreate(nil);//create a new UUID
    NSString *uuidString = (NSString*)CFUUIDCreateString(nil, uuidObj);
    CFRelease(uuidObj);
    return uuidString;
}

Hope this helps..