public void readHeader() throws IOException {
if (gotHeader) return;
if (iis == null) {
throw new IllegalStateException("Input source not set!");
}
metadata = new WBMPMetadata();
wbmpType = iis.readByte(); // TypeField
byte fixHeaderField = iis.readByte();
// check for valid wbmp image
if (fixHeaderField != 0 || !isValidWbmpType(wbmpType)) {
throw new IIOException(I18N.getString("WBMPImageReader2"));
}
metadata.wbmpType = wbmpType;
// Read image width
width = readMultiByteInteger();
metadata.width = width;
// Read image height
height = readMultiByteInteger();
metadata.height = height;
gotHeader = true;
}
private int readMultiByteInteger() throws IOException {
int value = iis.readByte();
int result = value & 0x7f;
while ((value & 0x80) == 0x80) {
result <<= 7;
value = iis.readByte();
result |= (value & 0x7f);
}
return result;
}
