ensureWritable0() — netty Function Reference

Source Code

buffer/src/main/java/io/netty/buffer/AbstractByteBuf.java lines 284–306

    final void ensureWritable0(int minWritableBytes) {
        final int writerIndex = writerIndex();
        final int targetCapacity = writerIndex + minWritableBytes;
        // using non-short-circuit & to reduce branching - this is a hot path and targetCapacity should rarely overflow
        if (targetCapacity >= 0 & targetCapacity <= capacity()) {
            ensureAccessible();
            return;
        }
        if (checkBounds && (targetCapacity < 0 || targetCapacity > maxCapacity)) {
            ensureAccessible();
            throw new IndexOutOfBoundsException(String.format(
                    "writerIndex(%d) + minWritableBytes(%d) exceeds maxCapacity(%d): %s",
                    writerIndex, minWritableBytes, maxCapacity, this));
        }

        // Normalize the target capacity to the power of 2.
        final int fastWritable = maxFastWritableBytes();
        int newCapacity = fastWritable >= minWritableBytes ? writerIndex + fastWritable
                : alloc().calculateNewCapacity(targetCapacity, maxCapacity);

        // Adjust to the new capacity.
        capacity(newCapacity);
    }