TBufStream

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

Buffered file stream

Declaration

Source position: objects.pp line 372

Type
  TBufStream = object (TDosStream)
    LastMode : Byte;
    BufSize : LongInt;
    BufPtr : LongInt;
    BufEnd : LongInt;
    Buffer : PByteArray;
    constructor Init(FileName: FNameStr; Mode: Word; Size: Word);
    destructor Done;  Virtual;
    procedure Close;  Virtual;
    procedure Flush;  Virtual;
    procedure Truncate;  Virtual;
    procedure Seek(Pos: LongInt);  Virtual;
    procedure Open(OpenMode: Word);  Virtual;
    procedure Read(var Buf; Count: LongInt);  Virtual;
    procedure Write(var Buf; Count: LongInt);  Virtual;
  end
  ;

Description

Bufstream implements a buffered file stream. That is, all data written to the stream is written to memory first. Only when the buffer is full, or on explicit request, the data is written to disk.

Also, when reading from the stream, first the buffer is checked if there is any unread data in it. If so, this is read first. If not the buffer is filled again, and then the data is read from the buffer.

The size of the buffer is fixed and is set when constructing the file.

This is useful if you need heavy throughput for your stream, because it speeds up operations.

Members

Member	Type	Visibility	Description
BufEnd	Field	default	End of data in buffer.
Buffer	Field	default	Actual buffer
BufPtr	Field	default	Pointer to current position in buffer
BufSize	Field	default	Size of buffer
Close	Method	default	Flush data and Close the file.
Done	Method	default	Close the file and cleans up the instance.
Flush	Method	default	FLush data from buffer, and write it to stream.
Init	Method	default	Initialize an instance of TBufStream and open the file.
LastMode	Field	default	Last file open mode
Open	Method	default	Open the file if it is closed.
Read	Method	default	Read data from the file to a buffer in memory.
Seek	Method	default	Set current position in file.
Truncate	Method	default	Flush buffer, and truncate the file at current position.
Write	Method	default	Write data to the file from a buffer in memory.

Inheritance

Class	Description
TBufStream	Buffered file stream

See also

Name	Description
Byte	An unsigned 8-bits integer
LongInt	A signed 32-bits integer
LongInt	A signed 32-bits integer
LongInt	A signed 32-bits integer
TByteArray	Array with maximum allowed number of bytes.