Re: Logging NSData

[Andreas Höschler]

Hi all,

I am logging out NSDictionaries that sometimes contain NSData instances as values. On MacOSX NSData::description is called to determine a string that is used in the output. I don't want to see tons of hex values for large NSData objects in the output and therefore wrote the following category:

@implementation NSData (SRDataExtension)

- (NSString *)description

{

return [NSString stringWithFormat:@"<data of length %d>", [self length]];

}

@end

This works great on MacOSX but not under GNUstep. It seems that description is not called under GNUstep when a dictionary is logged out with

NSLog(@"dic %@", dic);

Any idea?

GNUstep uses -descriptionWithLocale:

Perhaps we should change that if it's no longer used in OSX?

I have implemented

- (NSString *)descriptionWithLocale:(id)locale

{

  return [NSString stringWithFormat:@"<data of length %d>", [self length]];

}

no in my category, but this method isn't used either by NSLog(@"dic %@", dic)!? :-(

I checked core/base/Source/NSData.m but it has no implementation for descriptionWithLocale: either!?

AFAIU, your problem appears to be the implementation of NSDictionary's -description method (or really -descriptionWithLocale:indent:). This method is implemented by converting the dictionary into a (old-style) property list and that code converts NSData instances without invoking their -description (or -descriptionWithLocale:) methods (for the obvious reason). So I guess, you'll have to override NSDictionary -description for now as well.

The following modification in NSPropertyList.m solved my problem:

  else if ([obj isKindOfClass: [NSData class]])

    {

      if (x == NSPropertyListXMLFormat_v1_0)

{

  [dest appendBytes: "<data>\n" length: 7];

  encodeBase64(obj, dest);

  [dest appendBytes: "</data>\n" length: 8];

}

      else

{

     NSString *string = [obj description];

  [dest appendData:[string dataUsingEncoding:NSASCIIStringEncoding]];

  /* the code belows generates all the hey values, quit elog description

     const unsigned char *src;

  unsigned char *dst;

  int length;

  int i;

  int j;

  src = "" bytes];

  length = [obj length];

  #define num2char(num) ((num) < 0xa ? ((num)+'0') : ((num)+0x57))

  j = [dest length];

  [dest setLength: j + 2*length+(length > 4 ? (length-1)/4+2 : 2)];

  dst = [dest mutableBytes];

  dst[j++] = '<';

  for (i = 0; i < length; i++, j++)

    {

      dst[j++] = num2char((src[i]>>4) & 0x0f);

      dst[j] = num2char(src[i] & 0x0f);

      if ((i & 3) == 3 && i < length-1)

{

  // if we've just finished a 32-bit int, print a space 

  dst[++j] = ' ';

}

    }

  dst[j++] = '>';

     */

}

Thanks a lot!!

Andreas