Delphi中判断一个文件是不是JPG图片文件
function IsJpegFile(FileName: string): Boolean;
const
RightBuf :
array[0..3] of Byte = ($FF,$D8,$FF,$D9);
var
Buf: array[0..3] of
Byte;
begin
FillChar(Buf, 4, 0);
with TFileStream.Create(FileName, 0)
do begin
Position := 0;
ReadBuffer(Buf[0], 2);
Position :=
Size-2;
ReadBuffer(Buf[2], 2);
Free;
end;
Result :=
CompareMem(@RightBuf[0], @Buf[0], 4);
end;
procedure TForm1.Button1Click(Sender: TObject);//测试
begin
if
Self.OpenDialog1.Execute then
if IsJpegFile(Self.OpenDialog1.FileName)
then
Showmessage('Is Jpg File');
end;
根据扩展名判断,只是一种简单方法.这是根据文件头和文件尾判断....