Write или WriteBuffer?

[Pedro]

Здравствуйте!
Вот у многих компонентов есть метод write/read и writebuffer/readbuffer. Например в tmemorystream. Так вот, если не сложно, объясните в чем разница, и что из этого, в каких случаях используется? Заранее благодарю...

[mihali4]

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Вам перевод нужен ?

[Pedro]

К сожалению ни в delphi 2009 ни в 7 нет справки. Ну ничего, найду где-нибудь. Спасибо

[MalCer]

Вот вам из справки о методе Write():

Writes Count bytes from Buffer to the current position in the memory buffer and updates the current position by Count bytes.

Delphi syntax:

function Write(const Buffer; Count: Longint): Longint; override;

C++ syntax:

virtual int __fastcall Write(const void *Buffer, int Count);

Description

Use Write to insert Count bytes into the memory buffer of the memory stream, starting at the current position. Write will increase the size of the memory buffer, if necessary, to accommodate the data being written in. If the current position is not the end of the memory buffer, Write will overwrite the data following the current position.

Write updates the Size property to Position + Count, and sets the Position property to the new value of Size. Thus, any data that was stored in the memory stream in the Count bytes after the current position is lost when calling Write.

Write always writes the Count bytes in the Buffer, unless there is a memory failure. Thus, for TMemoryStream, Write is equivalent to the WriteBuffer method.

All other data-writing methods of a memory stream (WriteBuffer, WriteComponent) call Write to do the actual writing.

Итого WriteBuffer - это специальный буфер в памяти потока. Ес-но мы должны знать размер буфера. А read и readbuffer по аналогии

[mihali4]

А чего ж вы сразу не привели заодно:

Writes Count bytes from Buffer onto the stream and advances the current position of the stream by Count bytes.

Delphi syntax:

procedure WriteBuffer(const Buffer; Count: Longint);

C++ syntax:

void __fastcall WriteBuffer(const void *Buffer, int Count);

Description

Use WriteBuffer to save data to a stream. WriteBuffer and ReadBuffer are used in cases where the number of bytes is known and required, for example when reading in structures. Use WriteBuffer for standard file I/O streaming.

WriteBuffer is used internally for writing to a stream and copying from a stream. It is used by other objects, such as strings and lists, for writing strings stored in a buffer.

WriteBuffer calls Write to handle the actual writing. If the stream fails to write all the requested bytes, an EWriteError exception is raised.

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