NSUnarchiver

Inherits From: NSCoder : NSObject

Conforms To: NSObject (NSObject)

Declared In: Foundation/NSArchiver.h

Class Description

NSUnarchiver, a concrete subclass of NSCoder, defines objects that can decode a data structure, such as a graph of Objective C objects, from an archive. Such archives are produced by objects of the NSArchiver class. See the NSArchiver specification for an introduction to archiving.

General Exception Conditions

While unarchiving, NSUnarchiver performs a variety of consistency checks on the incoming data stream. NSUnarchiver raises an NSInconsistentArchiveException for a variety of reasons. Possible data errors leading to this exception are: unknown type descriptors in the data file; an array type descriptor is incorrectly terminated (missing ]); excess characters in a type descriptor; a null class found where a concrete class was expected; class not loaded.

Initializing an NSUnarchiver

- (id)initForReadingWithData:(NSData *)data Initializes an NSUnarchiver object from data object data. Raises NSInvalidArgumentException if the data argument is nil.

Decoding Objects

• + (id)unarchiveObjectWithData:(NSData *)data Decodes an archived object stored in data.
• + (id)unarchiveObjectWithFile:(NSString *)path Decodes an archived object stored in the file path.
• - (void)decodeArrayOfObjCType:(const char *)itemType count:(unsigned int)count Decodes an array of count data elements of the same at:(void *)array Objective C data itemType. It is your responsibility to release any objects derived in this way.

• - (BOOL)isAtEnd Returns YES if the end of data is reached, NO if more data follows.
• - (NSZone *)objectZone Returns the allocation zone for the unarchiver object.
• - (void)setObjectZone:(NSZone *)zone Sets the allocation zone for the unarchiver object to zone. If zone is nil, it sets it to the default zone.
• - (unsigned int)systemVersion Returns the system version number for the unarchived data.

• + (NSString *)classNameDecodedForArchiveClassName:(NSString *)nameInArchive Returns the class name used to archive instances of the class (nameInArchive). This may not be the original class name but another name encoded with NSArchiver's encodeClassName:intoClassName.
• + (void)decodeClassName:(NSString *)nameInArchive asClassName:(NSString *)trueName Decodes from the archived data a class name (nameInArchive) substituted for the real class name (trueName). This method enables easy conversion of unarchived data when there are name changes in classes.
• - (NSString *)classNameDecodedForArchiveClassName:(NSString *)nameInArchive Returns the class name used to archive instances of the class (nameInArchive). This may not be the original class name but another name encoded with NSArchiver's encodeClassName:intoClassName.
• - (void)decodeClassName:(NSString *)nameInArchive asClassName:(NSString *)trueName Decodes from the archived data a class name (nameInArchive) substituted for the real class name (trueName). This method enables easy conversion of unarchived data when there are name changes in classes.