Reference for package '#rtl'

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.