/**
* Truncate the file.
*
* @param newLength the new length
*/
void truncate(long newLength) {
changeLength(newLength);
long end = MathUtils.roundUpLong(newLength, BLOCK_SIZE);
if (end != newLength) {
int lastPage = (int) (newLength >>> BLOCK_SIZE_SHIFT);
expand(data, lastPage);
ByteBuffer d = data[lastPage];
for (int i = (int) (newLength & BLOCK_SIZE_MASK); i < BLOCK_SIZE; i++) {
d.put(i, (byte) 0);
}
if (compress) {
compressLater(data, lastPage);
}
}
}
/**
* Read or write.
*
* @param pos the position
* @param b the byte array
* @param off the offset within the byte array
* @param len the number of bytes
* @param write true for writing
* @return the new position
*/
long readWrite(long pos, ByteBuffer b, int off, int len, boolean write) {
long end = pos + len;
if (end > length) {
if (write) {
changeLength(end);
} else {
len = (int) (length - pos);
}
}
while (len > 0) {
int l = (int) Math.min(len, BLOCK_SIZE - (pos & BLOCK_SIZE_MASK));
int page = (int) (pos >>> BLOCK_SIZE_SHIFT);
expand(data, page);
ByteBuffer block = data[page];
int blockOffset = (int) (pos & BLOCK_SIZE_MASK);
if (write) {
ByteBuffer tmp = b.slice();
tmp.position(off);
tmp.limit(off + l);
block.position(blockOffset);
block.put(tmp);
} else {
block.position(blockOffset);
ByteBuffer tmp = block.slice();
tmp.limit(l);
int oldPosition = b.position();
b.position(off);
b.put(tmp);
// restore old position
b.position(oldPosition);
}
if (compress) {
compressLater(data, page);
}
off += l;
pos += l;
len -= l;
}
return pos;
}
