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Important: The information in this document is obsolete and should not be used for new development.
NSMutableData
| Inherits from | |
| Implements | |
| Package | com.apple.cocoa.foundation |
| Companion guide |
Class at a Glance
An NSMutableData object stores mutable data in the form of bytes. The size of the data is subject to a 2GB limit.
Principal Attributes
A count of the number of bytes in the mutable data object
The sequence of bytes contained in the mutable data object
Creation
NSMutableDataCreates an NSMutableData object.
Primitive Methods
setLengthExtends or truncates the number of bytes in the NSMutableData object.
Overview
NSMutableData (and its superclass NSData) provide data objects, object-oriented wrappers for byte buffers. Data objects let simple allocated buffers (that is, data with no embedded pointers) take on the behavior of Foundation objects. They are typically used for data storage and are also useful in Distributed Objects applications, where data contained in data objects can be copied or moved between applications. NSData creates static data objects, and NSMutableData creates dynamic data objects. You can easily convert one type of data object to the other with the constructor that takes an NSData or NSMutableData as an argument.
Tasks
Constructors
Adjusting Capacity
Adding Data
Modifying Data
Constructors
NSMutableData
public NSMutableData()
Discussion
Creates an empty data object. This method is declared primarily for the use of mutable subclasses of NSData.
public NSMutableData(java.net.URL aURL)
Discussion
Creates a data object with the data from the location specified by aURL.
public NSMutableData(NSData aData)
Discussion
Creates a data object containing the contents of another data object, aData.
public NSMutableData(int length)
Discussion
Creates data object with enough memory to hold length bytes. Fills the object with zeros up to length.
Instance Methods
appendData
Appends the contents of a data object otherData to the receiver.
public void appendData(NSData otherData)
increaseLengthBy
Increases the length of the receiver by extraLength.
public void increaseLengthBy(int extraLength)
Discussion
The additional bytes are all set to 0.
See Also
resetBytesInRange
Specifies a range within the contents of the receiver to be replaced by zeros.
public void resetBytesInRange(NSRange range)
Discussion
If the location of range isn’t within the receiver’s range of bytes, a RangeException is thrown. The receiver is resized to accommodate the new bytes, if necessary.
setData
Replaces the entire contents of the receiver with the contents of aData.
public void setData(NSData aData)
setLength
Extends or truncates a mutable data object to length.
public void setLength(int length)
Discussion
If the mutable data object is extended, the additional bytes are filled with zeros.
See Also
© 1997, 2006 Apple Computer, Inc. All Rights Reserved. (Last updated: 2006-07-24)