读写Unicode和UTF8格式文件

 

//----------------------------------------------// Unit Name: FileExt.pas// Comment: 读写UTF8和UNICODE格式文件的一组函数// Author: xieyunc 改自网络// Date : 2007-11-23 10:47:59//----------------------------------------------unit FileExt;interface  uses SysUtils,Windows,Types,Classes;const  utf8Head:  Array[0..2] of Char = (#239,#$bb,#$bf);  unicodeHead: Array[0..1] of Char = (#255,#$fe);  function ReadUtf8File(const filename:string):UTF8String;  procedure WriteUtf8File(const filename:string;mem:Utf8String);  function ReadUnicodeFile(const filename:string):WideString;  procedure WriteUnicodeFile(const filename:string;mem:Widestring);implementation// read utf8 filefunction ReadUtf8File(const filename:string):Utf8String;var  memoStream:TFileStream;  buf:array of Char;begin  memoStream:=TFileStream.Create(filename, fmOpenRead);  try    setlength(buf,memoStream.size);    memoStream.ReadBuffer(buf[0], memoStream.size);    //utf-8 file    if (buf[0]=Utf8Head[0]) and (buf[1]=Utf8Head[1]) and (buf[2]=Utf8Head[2]) then    begin        FillChar(buf, SizeOf(buf), #0);        memoStream.Seek(3,soFromBeginning);        setlength(buf,memoStream.size-3);        memoStream.ReadBuffer(buf[0], memoStream.size-3);        result:=Utf8String(buf);        exit;    end else result:=UTF8Encode(WideString('文件不是UTF8格式！'));  finally    memoStream.Free;  end;end;// read unicode filefunction ReadUnicodeFile(const filename:string):WideString;var  memoStream:TFileStream;  buf:array of Char;begin  memoStream:=TFileStream.Create(filename, fmOpenRead);  try    setlength(buf,memoStream.size);    memoStream.ReadBuffer(buf[0], memoStream.size);    //unicode file    if (buf[0]=UnicodeHead[0]) and (buf[1]=UnicodeHead[1]) then    begin      FillChar(buf, SizeOf(buf), #0);      memoStream.Seek(2,soFromBeginning);      setlength(buf,memoStream.size-2);      memoStream.ReadBuffer(buf[0], memoStream.size-2);      result:=PWideChar(buf);      exit;    end else result:=WideString('文件不是UNICODE格式！');  finally    memoStream.Free;  end;end;procedure WriteUnicodeFile(const filename:string;mem:Widestring);var  wms:TMemoryStream;begin  wms:=TMemoryStream.Create;  wms.WriteBuffer(unicodeHead,length(unicodeHead));  wms.WriteBuffer(PChar(mem)^,length(mem)*2);  wms.SaveToFile(filename);  wms.Free;end;procedure WriteUtf8File(const filename:string;mem:Utf8String);var  wms:TMemoryStream;begin  wms:=TMemoryStream.Create;  wms.WriteBuffer(utf8Head,length(utf8Head));  wms.WriteBuffer(pchar(mem)^,length(Ansistring(mem)));  wms.SaveToFile(filename);  wms.Free;end;end.
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