<% '****************************************************************** 'CheckFileType 函數(shù)用來檢查文件是否為圖片文件 '參數(shù)filename是本地文件的路徑 '如果是文件jpeg,gif,bmp,png圖片中的一種，函數(shù)返回true，否則返回false '****************************************************************** const adTypeBinary=1 dim jpg(1):jpg(0)=CByte(&HFF):jpg(1)=CByte(&HD8) dim bmp(1):bmp(0)=CByte(&H42):bmp(1)=CByte(&H4D) dim png(3):png(0)=CByte(&H89):png(1)=CByte(&H50):png(2)=CByte(&H4E):png(3)=CByte(&H47) dim gif(5):gif(0)=CByte(&H47):gif(1)=CByte(&H49):gif(2)=CByte(&H46):gif(3)=CByte(&H39):gif(4)=CByte(&H38):gif(5)=CByte(&H61) function CheckFileType(filename) on error resume next CheckFileType=false dim fstream,fileExt,stamp,i fileExt=mid(filename,InStrRev(filename,".")+1) set fstream=Server.createobject("ADODB.Stream") fstream.Open fstream.Type=adTypeBinary fstream.LoadFromFile filename fstream.position=0 select case fileExt case "jpg","jpeg" stamp=fstream.read(2) for i=0 to 1 if ascB(MidB(stamp,i+1,1))=jpg(i) then CheckFileType=true else CheckFileType=false next case "gif" stamp=fstream.read(6) for i=0 to 5 if ascB(MidB(stamp,i+1,1))=gif(i) then CheckFileType=true else CheckFileType=false next case "png" stamp=fstream.read(4) for i=0 to 3 if ascB(MidB(stamp,i+1,1))=png(i) then CheckFileType=true else CheckFileType=false next case "bmp" stamp=fstream.read(2) for i=0 to 1 if ascB(MidB(stamp,i+1,1))=bmp(i) then CheckFileType=true else CheckFileType=false next end select fstream.Close set fseteam=nothing if err.number<>0 then CheckFileType=false end function %> |
