TCustomMemoryStream

[Properties (by Name)][Methods (by Name)][Events (by Name)]

Abstract stream that stores its data in memory.

Declaration

Source position: classesh.inc line 1193

Type
  TCustomMemoryStream = class (TStream)
  private
    FMemory : Pointer;
    FSize : PtrInt;
    FPosition : PtrInt;
    FSizeBoundsSeek : Boolean;
  protected
    function GetSize : Int64;  Override;
    function GetPosition : Int64;  Override;
    procedure SetPointer(Ptr: Pointer; ASize: PtrInt);
  public
    function Read(var Buffer; Count: LongInt) : LongInt;  Override;
    function Seek(const Offset: Int64; Origin: TSeekOrigin) : Int64
                 ;  Override;
    procedure SaveToStream(Stream: TStream);
    procedure SaveToFile(const FileName: string);
    Memory : Pointer;
    SizeBoundsSeek : Boolean;
  end
  ;

Description

TCustomMemoryStream is the parent class for streams that stored their data in memory. It introduces all needed functions to handle reading from and navigating through the memory, and introduces a Memory property which points to the memory area where the stream data is kept.

The only thing which TCustomMemoryStream does not do is obtain memory to store data when writing data or the writing of data. This functionality is implemented in descendant streams such as TMemoryStream . The reason for this approach is that this way it is possible to create e.g. read-only descendants of TCustomMemoryStream that point to a fixed part in memory which can be read from, but not written to.

Remark

Since TCustomMemoryStream is an abstract class, do not create instances of TMemoryStream directly. Instead, create instances of descendants such as TMemoryStream .
!!!

Members

Member	Type	Visibility	Description
FMemory	Field	private
FPosition	Field	private
FSize	Field	private
FSizeBoundsSeek	Field	private
GetPosition	Method	protected
GetSize	Method	protected	return the size of the stream.
Memory	Property	public	Pointer to the data kept in the memory stream.
Read	Method	public	Reads Count bytes from the stream into buffer.
SaveToFile	Method	public	Writes the contents of the stream to a file.
SaveToStream	Method	public	Writes the contents of the memory stream to another stream.
Seek	Method	public	Sets a new position in the stream.
SetPointer	Method	protected	Sets the internal memory pointer and size of the memory block.
SizeBoundsSeek	Property	public

Inheritance

Class	Description
TCustomMemoryStream	Abstract stream that stores its data in memory.

See also

Name	Description
PtrInt	Signed integer type with same size as Pointer.
PtrInt	Signed integer type with same size as Pointer.
TMemoryStream	Standard implementation of a stream that stores its data in memory
TStream	Base class for streams.

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