Delphi读写UTF-8、Unicode格式文本文件

发布时间：2020-12-15 10:00:05 所属栏目：大数据来源：网络整理

导读：// UTF-8文件写入函数 procedure SaveUTFFile (const FileName: string; S: string; WriteHeader: Boolean = True); var ? MemStream: TMemoryStream; ? HeaderStr: String; begin ? if S = '' then Exit; ? MemStream := TMemoryStream.Create; ? try ??? i

// UTF-8文件写入函数
procedure SaveUTFFile(const FileName: string; S: string; WriteHeader: Boolean = True);
var
? MemStream: TMemoryStream;
? HeaderStr: String;
begin
? if S = '' then Exit;

? MemStream := TMemoryStream.Create;
? try
??? if WriteHeader then
??? begin
????? HeaderStr:=#$EF#$BB#$BF;
????? MemStream.Write(HeaderStr[1],3);
??? end;

??? S := AnsiToUtf8(S);
??? MemStream.Write(S[1],Length(S));
??? MemStream.Position := 0;

??? MemStream.SaveToFile(FileName);
? finally
??? MemStream.Free;
? end;
end;

// UtF-8文件读取函数
function LoadUTFFile(const FileName: string; ReadHeader: Boolean = True): string;
var
? MemStream: TMemoryStream;
? S,HeaderStr:string;
begin
? Result:='';
? if not FileExists(FileName) then Exit;

? MemStream := TMemoryStream.Create;
? try
??? MemStream.LoadFromFile(FileName);
??? if ReadHeader then
??? begin
????? SetLength(HeaderStr,3);
????? MemStream.Read(HeaderStr[1],3);

????? if HeaderStr = #$EF#$BB#$BF then
????? begin
??????? SetLength(S,MemStream.Size - 3);
??????? MemStream.Read(S[1],MemStream.Size - 3);
????? end;
??? end else
??? begin
????? SetLength(S,MemStream.Size);
????? MemStream.Read(S[1],MemStream.Size);
??? end;
???
??? Result := Utf8ToAnsi(S);
? finally
??? MemStream.Free;
? end;
end;

// Unicode文件写入函数
procedure SaveUnicodeFile(const FileName:string; const S: string; WriteHeader: Boolean = True);
var
? MemStream: TMemoryStream;
? HeaderStr: string;
? WStr: WideString;
begin
? if S = '' then exit;

? MemStream := TMemoryStream.Create;
? try
??? if WriteHeader then
??? begin
????? HeaderStr := #$FF#$FE;
????? MemStream.Write(HeaderStr[1],2);
??? end;
???
??? WStr := WideString(S);
??? MemStream.Write(WStr[1],Length(WStr)*2);
??? MemStream.Position := 0;
??? MemStream.SaveToFile(FileName);
? finally
??? MemStream.Free;
? end;
end;

// Unicode文件读取函数
function LoadUnicodeFile(const FileName: string; ReadHeader: Boolean = True): string;
var
? MemStream: TMemoryStream;
? FlagStr: String;
? WStr: WideString;
begin
? Result := '';
? if not FileExists(FileName) then Exit;

? MemStream := TMemoryStream.Create;
? try
??? MemStream.LoadFromFile(FileName);

??? if ReadHeader then ??? begin ????? SetLength(FlagStr,2); ????? MemStream.Read(FlagStr[1],2); ????? ????? if FlagStr = #$FF#$FE then ????? begin ??????? SetLength(WStr,(MemStream.Size-2) div 2); ??????? MemStream.Read(WStr[1],MemStream.Size - 2); ????? end; ??? end else ??? begin ????? SetLength(WStr,MemStream.Size div 2); ????? MemStream.Read(WStr[1],MemStream.Size); ??? end; ??? ??? Result := AnsiString(WStr); ? finally ??? MemStream.Free; ? end; end;

（编辑：李大同）

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