[bug #15226] Unarchived objects do not equal archived objects

[Oliver Langer]

URL:
  <http://savannah.gnu.org/bugs/?func=detailitem&item_id=15226>

                 Summary: Unarchived objects do not equal archived objects
                 Project: GNUstep
            Submitted by: kokosmakrone
            Submitted on: Do 15.12.2005 um 23:33
                Category: Base/Foundation
                Severity: 3 - Normal
              Item Group: Bug
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open

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Details:

Take the following scenario into account: You store/archive a string in a
NSData d1 object. Afterwards you run a query and want to load this string by
loading/unarchiving. After, you want this previously loaded string being
stored in another NSData d2 object.  You would expect that the content of d2
equals d1 which is not the  case. 

Behind the scene: The first string is being allocated as an instance of
GSInlineString. Encoding and afterwards decoding this object returns an
instance of GSUnicodeBufferString. Encoding this instance seems to differ
from encoding an instance of GSInlineString.

The following code shows this bug when leaving KEYED_ARCHIVER undefined.
Defining it shows the potential workaround (which costs much more space):

//#define KEYED_ARCHIVER 1

  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
  NSString *sOriginal, *sLoaded;
  NSMutableData *dataOriginal, *dataLoaded;
#if defined(KEYED_ARCHIVER)
  NSKeyedArchiver *arOriginal, *arLoaded;
#else
  NSArchiver *arOriginal, *arLoaded;
#endif
  char *b1, *b2;

  sOriginal = [[[NSString alloc] initWithString: @"bla"] autorelease];
  dataOriginal = [[[NSMutableData alloc] init] autorelease];
#if defined(KEYED_ARCHIVER)
  arOriginal = [[[NSKeyedArchiver alloc]
    initForWritingWithMutableData: dataOriginal] autorelease];
#else
  arOriginal = [[[NSArchiver alloc]
    initForWritingWithMutableData: dataOriginal] autorelease];
#endif

#if defined(KEYED_ARCHIVER)
  [arOriginal encodeObject: sOriginal forKey: @"bla"];
#else
  [arOriginal encodeObject: sOriginal];
#endif

#if defined(KEYED_ARCHIVER)
  [arOriginal finishEncoding];
#endif

#if defined(KEYED_ARCHIVER)
  arOriginal = [[[NSKeyedUnarchiver alloc]
    initForReadingWithData: dataOriginal] autorelease];
#else
  arOriginal = [[[NSUnarchiver alloc]
    initForReadingWithData: dataOriginal] autorelease];
#endif

#if defined(KEYED_ARCHIVER)
  sLoaded = [[[arOriginal decodeObjectForKey: @"bla" ] retain] autorelease];
#else
  sLoaded = [[[arOriginal decodeObject] retain] autorelease];
#endif
  NSLog( @"LOADED: %@", sLoaded );

  dataLoaded = [[[NSMutableData alloc] init] autorelease];

#if defined(KEYED_ARCHIVER)
  arLoaded = [[[NSKeyedArchiver alloc]
    initForWritingWithMutableData: dataLoaded] autorelease];
#else
  arLoaded = [[[NSArchiver alloc]
    initForWritingWithMutableData: dataLoaded] autorelease];
#endif

#if defined(KEYED_ARCHIVER)
  [arLoaded encodeObject: sLoaded forKey: @"bla" ];
#else
  [arLoaded encodeObject: sLoaded ];
#endif

#if defined(KEYED_ARCHIVER)
  [arLoaded finishEncoding];
#endif

  NSLog( @"Length: orginal=%d, loaded=%d",
    [dataOriginal length], [dataLoaded length] );

  if( [dataOriginal length] != [dataLoaded length] ) {
    NSLog( @"Data differs!" );
  } else {
    BOOL buffersAreEqual = YES;
    int i;

    b1 = [dataOriginal bytes];
    b2 = [dataLoaded bytes];

    for( i = 0; i < [dataOriginal length]; i++ ) {
      if( b1[ i ] != b2[ i ] ) {
        buffersAreEqual = NO;
        break;
      }
    }

    if( buffersAreEqual ) {
      NSLog( @"Buffers are equal!" );
    } else {
      NSLog( @"Buffers DIFFER!" );
    }
  }
  exit( 0 );








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