private SendBuffer acquire(ChannelBuffer src) {
final int size = src.readableBytes();
if (size == 0) {
return EMPTY_BUFFER;
}
if (src instanceof CompositeChannelBuffer && ((CompositeChannelBuffer) src).useGathering()) {
return new GatheringSendBuffer(src.toByteBuffers());
}
if (src.isDirect()) {
return new UnpooledSendBuffer(src.toByteBuffer());
}
if (src.readableBytes() > DEFAULT_PREALLOCATION_SIZE) {
return new UnpooledSendBuffer(src.toByteBuffer());
}
Preallocation current = this.current;
ByteBuffer buffer = current.buffer;
int remaining = buffer.remaining();
PooledSendBuffer dst;
if (size < remaining) {
int nextPos = buffer.position() + size;
ByteBuffer slice = buffer.duplicate();
buffer.position(align(nextPos));
slice.limit(nextPos);
current.refCnt++;
dst = new PooledSendBuffer(current, slice);
} else if (size > remaining) {
this.current = current = getPreallocation();
buffer = current.buffer;
ByteBuffer slice = buffer.duplicate();
buffer.position(align(size));
slice.limit(size);
current.refCnt++;
dst = new PooledSendBuffer(current, slice);
} else { // size == remaining
current.refCnt++;
this.current = getPreallocation0();
dst = new PooledSendBuffer(current, current.buffer);
}
ByteBuffer dstbuf = dst.buffer;
dstbuf.mark();
src.getBytes(src.readerIndex(), dstbuf);
dstbuf.reset();
return dst;
}
