Delphi Read-Write UTF-8, Unicode format text file not tested

//UTF-8 File Write functionprocedureSaveutffile (ConstFileName:string; Sstring; Writeheader:boolean =True);varMemstream:tmemorystream; headerstr:string;beginifS ="'  ThenExit; Memstream:= Tmemorystream.Create;TryifWriteheader ThenbeginHeaderstr:=# $EF # $BB # $BF; Memstream.write (headerstr[1],3);End; S: =AnsiToUtf8 (S); Memstream.write (s[1], Length (S)); Memstream.position:=0; Memstream.savetofile (FileName);finallyMemstream.free;End;End;//UtF-8 file read functionfunctionLoadutffile (ConstFileName:string; Readheader:boolean = True):string;varMemstream:tmemorystream; S, Headerstr:string;beginResult:="';if  notFileExists (FileName) ThenExit; Memstream:= Tmemorystream.Create;TryMemstream.loadfromfile (FileName);ifReadheader ThenbeginSetLength (HEADERSTR,3); Memstream.read (headerstr[1],3);ifHeaderstr = # $EF # $BB # $BF ThenbeginSetLength (S, Memstream.size-3); Memstream.read (s[1], Memstream.size-3);End;End ElsebeginSetLength (S, memstream.size); Memstream.read (s[1], memstream.size);End; Result:=Utf8toansi (S);finallyMemstream.free;End;End;//Unicode file Write functionprocedureSaveunicodefile (ConstFileName:string;ConstSstring; Writeheader:boolean =True);varMemstream:tmemorystream; HEADERSTR:string; wstr:widestring;beginifS ="'  Thenexit; Memstream:= Tmemorystream.Create;TryifWriteheader ThenbeginHeaderstr:=# $FF # $FE; Memstream.write (headerstr[1],2);End; WSTR:=widestring (S); Memstream.write (wstr[1], Length (WSTR) *2); Memstream.position:=0; Memstream.savetofile (FileName);finallyMemstream.free;End;End;//Unicode file read functionfunctionLoadunicodefile (ConstFileName:string; Readheader:boolean = True):string;varMemstream:tmemorystream; flagstr:string; wstr:widestring;beginResult:="';if  notFileExists (FileName) ThenExit; Memstream: = Tmemorystream.Create;TryMemstream.loadfromfile (FileName);ifReadheader ThenbeginSetLength (FLAGSTR,2); Memstream.read (flagstr[1],2);ifFlagstr = # $FF # $FE ThenbeginSetLength (Wstr, (Memstream.size-2)Div 2); Memstream.read (wstr[1], Memstream.size-2);End;End ElsebeginSetLength (wstr, Memstream.sizeDiv 2); Memstream.read (wstr[1], memstream.size);End; Result:=ansistring (WSTR);finallyMemstream.free;End;End;//Save FileprocedureSaveToFile (ConstFileName:string;ConstSstring);varF:textfile;beginAssignFile (F, FileName);//Make a connection to the file with the F variable, and you can use the F variable to manipulate the file later. Rewrite (F);//to open a file in an additional wayWriteln (F, S);//appends the contents of the S variable to the end of the text. CloseFile (F);//Close FileEnd;

typeTtextformat=(Tfansi,tfunicode,tfunicodebigendian,tfutf8);ConstTextformatflag:Array[Tfansi. TfUtf8] ofWord= ($0000, $FFFE, $FEFF, $EFBB); functionWordlohiexchange (W:word): Word;Register;ASMXCHG AL, AHEnd; {textformat Return text encoding type, stext unprocessed text}procedureReadTextFile (ConstFileName:string; varTextformat:ttextformat;varStext:string);varW:word; B:byte;begin   withTFileStream.Create(Filename,fmopenreadorFmsharedenynone) Do  TryRead (W,2); W:=wordlohiexchange (w);//because it is read in the Word data type, the high and low byte interchange    ifW = Textformatflag[tfunicode] ThenTextFormat:=TfunicodeElse ifW = Textformatflag[tfunicodebigendian] ThenTextFormat:=TfunicodebigendianElse ifW = Textformatflag[tfutf8] Then    beginRead (b,1);//note here that UFT-8 must skip three bytes. textformat:=TfUtf8; End Else    beginTextFormat:=Tfansi; Position:=0; End; SetLength (Stext,size-Position); Readbuffer (stext[1],size-Position); finallyFree ; End;End;

Delphi Read-Write UTF-8, Unicode format text file not tested