determining image file types

[torturedmind]

every once in a while, our clients send us image files without their extension name (.jpg, .gif, .bmp, whatever). this means that only the filename itself will be left untouched. am wondering, is there some way to determine the image file's type so that the program can save it on a temporary location and then load it in it's default application? like, if the program determined that it's a bmp, then it will save it in, say, c:\windows\temp with the extension .bmp and then load the file in ms paint.

i will be grateful for any help you guys can extend. peace!

kilroy
philippines

"Once a king, always a king. But being a knight is more than enough."

 

[torturedmind]

i forgot to mention, we're using vfp6 on a win98se platform. thanks again.

peace!

kilroy
philippines

"Once a king, always a king. But being a knight is more than enough."

 

[Juris]

The first, that comes to - try to read file header by VFP file low level functions, for example:

lnHandle = FOPEN("disk_letter:\some_directory\some_file_without_extension")
lcString= FREAD(nHandle,3) && gif-file have leftmost 3 symbols = "GIF"
? lcString
=FCLOSE(lnHandle)

BMP leftmost 2 symbols are BM
etc

Juri Shutenko
Municipality of Maardu, Estonia

http://kodu.neti.ee/~juri4

http://www.hot.ee/jurisfox

 

[GriffMG]

Following Juris's tip:

%PDF - first four characters of a .pdf file
GIF - first three of a .gif
II* - first three of a .tif
FF D8 FF - Hex values of first three characters of a .jpg

Hope this helps

Regards

Griff
Keep [Smile]ing

 

[torturedmind]

thanks guys. i'll try this later. peace!

kilroy
philippines

"Once a king, always a king. But being a knight is more than enough."