public void write(Tag tag, RandomAccessFile raf, RandomAccessFile tempRaf)
throws CannotWriteException, IOException {
FileChannel fc = raf.getChannel();
int oldTagSize = 0;
if (tagExists(fc)) {
// read the length
if (!canOverwrite(raf))
throw new CannotWriteException("Overwritting of this kind of ID3v2 tag not supported yet");
fc.position(6);
ByteBuffer buf = ByteBuffer.allocate(4);
fc.read(buf);
oldTagSize = (buf.get(0) & 0xFF) << 21;
oldTagSize += (buf.get(1) & 0xFF) << 14;
oldTagSize += (buf.get(2) & 0xFF) << 7;
oldTagSize += buf.get(3) & 0xFF;
oldTagSize += 10;
// System.err.println("Old tag size: "+oldTagSize);
int newTagSize = tc.getTagLength(tag);
if (oldTagSize >= newTagSize) {
// replace
// System.err.println("Old ID32v Tag found, replacing the old
// tag");
fc.position(0);
fc.write(tc.convert(tag, oldTagSize - newTagSize));
// ID3v2 Tag Written
return;
}
}
// create new tag with padding
// System.err.println("Creating a new ID3v2 Tag");
fc.position(oldTagSize);
if (fc.size() > 15 * 1024 * 1024) {
FileChannel tempFC = tempRaf.getChannel();
tempFC.position(0);
tempFC.write(tc.convert(tag, Id3v2TagCreator.DEFAULT_PADDING));
tempFC.transferFrom(fc, tempFC.position(), fc.size() - oldTagSize);
fc.close();
} else {
ByteBuffer[] content = new ByteBuffer[2];
content[1] = ByteBuffer.allocate((int) fc.size());
fc.read(content[1]);
content[1].rewind();
content[0] = tc.convert(tag, Id3v2TagCreator.DEFAULT_PADDING);
fc.position(0);
fc.write(content);
}
}
