/**
* Determines from the magic number whether the given InputStream points to a DDS image. The given
* InputStream must return true from markSupported() and support a minimum of four bytes of
* read-ahead.
*
* @param in Stream to check
* @return true if input stream is DDS image or false otherwise
* @throws java.io.IOException if an I/O exception occurred
*/
public static boolean isDDSImage(InputStream in) throws IOException {
if (!(in instanceof BufferedInputStream)) {
in = new BufferedInputStream(in);
}
if (!in.markSupported()) {
throw new IOException(
"Can not test non-destructively whether given InputStream is a DDS image");
}
in.mark(4);
int magic = 0;
for (int i = 0; i < 4; i++) {
int tmp = in.read();
if (tmp < 0) {
in.reset();
return false;
}
magic = ((magic >>> 8) | (tmp << 24));
}
in.reset();
return (magic == MAGIC);
}
