TFileStream：從文件中讀取數據塊並在Delphi 7中將其替換

Question

我想從文件中讀取一個字節塊（例如400KB），替換緩沖區中的一些文本，然后將其寫入文件。 最初，我嘗試使用帶有字節緩沖區數組的TFileStream，但是后來我遇到了stringreplace與string一起工作的問題。 源數據是txt UTF-8。 這就是我所擁有的：

var
  SS,ST: TFileStream;
  Buffer: string;
  sf,tf,TempStr: string;
  i: Integer;
begin
  sf := 'U:\SYSTEM\enwiktionary-latest-stub-articles\stub-articles.xml';
  tf := 'A:1.txt';
  SS := TFileStream.Create(sf, fmOpenRead);
  ST := TFileStream.Create(tf, fmCreate or fmOpenWrite);
  try
    SS.Read(Buffer, sizeof(Buffer));
    Buffer := stringreplace(Buffer, '<page>','<p>', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '</page>','</p>', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '<title>','<t>', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '</title>','</t>', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '<ns>','<n', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '</ns>','>', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '<revision>','<r>', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '</revision>','</r>', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '<id>','<i', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '</id>','>', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '<parentid>','<pi', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '</parentid>','>', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '<contributor>','', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '</contributor>','', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '<username>','<u>', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '</username>','</u>', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '<comment>','<c>', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '</comment>','</c>', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '<text id="','<t =', [rfReplaceAll]);
    Buffer := stringreplace(Buffer, '" bytes="',' b=', [rfReplaceAll]);
    ST.Write(Buffer, sizeof(Buffer));
  finally
    SS.Free;
  end;

Buffer := stringreplace使運行時錯誤訪問沖突。

Answer 1

使用UTF8緩沖字符串並為字符串主體分配位置 ：

 Buffer: AnsiString; //type UTF8String = AnsiString;
 ...
 SetLength(Buffer, BlockSize)
 SS.Read(PAnsiChar(Buffer)^, BlockSize);
 ...
 ST.Write(PAnsiChar(Buffer)^, Length(Buffer)); 

但是，通過這種方法，您可以在塊的邊界松開圖案。 為什么不使用TStringList ，在其中加載所有內容並使用其行？

Answer 2

一個有效的例子。

var
    ifname,ofname:string;
    sourceStream, targetStream: TFileStream;
    filesizevalue, size:integer;
    Buffer: AnsiString;
begin
  ifname := 'U:\SYSTEM\enwiktionary-latest-stub-articles\stub-articles.xml';
  ofname := 'A:1.txt';
  filesizevalue:=900000;
  size := 1;
  SetLength(Buffer, filesizevalue);
  sourceStream := TFileStream.Create(ifname, fmOpenRead);
  targetStream := TFileStream.Create(ofname, fmCreate or fmOpenWrite);
  try
    sourceStream.seek(0, soFromBeginning);
    sourceStream.ReadBuffer(PAnsiChar(Buffer)^, filesizevalue * size);

    buffer := stringreplace(buffer, '<page>','<p>', [rfReplaceAll]);
    buffer := stringreplace(buffer, '</page>','</p>', [rfReplaceAll]);
    buffer := stringreplace(buffer, '<title>','<t>', [rfReplaceAll]);
    buffer := stringreplace(buffer, '</title>','</t>', [rfReplaceAll]);
    buffer := stringreplace(buffer, '<ns>','<n', [rfReplaceAll]);
    buffer := stringreplace(buffer, '</ns>','>', [rfReplaceAll]);
    buffer := stringreplace(buffer, '<revision>','<r>', [rfReplaceAll]);
    buffer := stringreplace(buffer, '</revision>','</r>', [rfReplaceAll]);
    buffer := stringreplace(buffer, '<id>','<i', [rfReplaceAll]);
    buffer := stringreplace(buffer, '</id>','>', [rfReplaceAll]);
    buffer := stringreplace(buffer, '<parentid>','<pi', [rfReplaceAll]);
    buffer := stringreplace(buffer, '</parentid>','>', [rfReplaceAll]);
    buffer := stringreplace(buffer, '<contributor>','', [rfReplaceAll]);
    buffer := stringreplace(buffer, '</contributor>','', [rfReplaceAll]);
    buffer := stringreplace(buffer, '<username>','<u>', [rfReplaceAll]);
    buffer := stringreplace(buffer, '</username>','</u>', [rfReplaceAll]);
    buffer := stringreplace(buffer, '<comment>','<c>', [rfReplaceAll]);
    buffer := stringreplace(buffer, '</comment>','</c>', [rfReplaceAll]);
    buffer := stringreplace(buffer, '<text id="','<t =', [rfReplaceAll]);
    buffer := stringreplace(buffer, '" bytes="',' b=', [rfReplaceAll]);
    targetStream.Write(PAnsiChar(buffer)^, length(buffer) );
  finally
     sourceStream.free;
     targetStream.free;
  end;