dstIndex += 4;

        System.arraycopy(this.fileId, 0, dst, dstIndex, 16);
        dstIndex += 16;

        SMBUtil.writeInt2(dstIndex - getHeaderStart(), dst, bufferOffsetOffset);
        final int len = this.info.encode(dst, dstIndex);
        SMBUtil.writeInt4(len, dst, bufferLengthOffset);
        dstIndex += len;
        return dstIndex - start;
    }

        dstIndex += 2;
        SMBUtil.writeInt8(this.previousSessionId, dst, dstIndex);
        dstIndex += 8;
        SMBUtil.writeInt2(dstIndex - getHeaderStart(), dst, offsetOffset);

        dstIndex += pad8(dstIndex);

        if (this.token != null) {
            System.arraycopy(this.token, 0, dst, dstIndex, this.token.length);

        SMBUtil.writeInt2(50, buffer, bufferIndex + 2);
        // Set buffer length
        SMBUtil.writeInt4(8, buffer, bufferIndex + 4);

        // Mock getHeaderStart
        response = spy(response);
        when(response.getHeaderStart()).thenReturn(0);

        // Write FileInternalInfo data at the buffer offset
        // FileInternalInfo expects 8 bytes (IndexNumber as int8)

            dstIndex += 2;
        }

        dstIndex += pad8(dstIndex);

        if (this.negotiateContexts != null && this.negotiateContexts.length != 0) {
            SMBUtil.writeInt4(dstIndex - getHeaderStart(), dst, negotitateContextOffsetOffset);
            for (final NegotiateContextRequest nc : this.negotiateContexts) {
                SMBUtil.writeInt2(nc.getContextType(), dst, dstIndex);

            SMBUtil.writeInt2(0, dst, fnLengthOffset);
        } else {
            final byte[] fnBytes = this.fileName.getBytes(StandardCharsets.UTF_16LE);
            SMBUtil.writeInt2(dstIndex - getHeaderStart(), dst, fnOffsetOffset);
            SMBUtil.writeInt2(fnBytes.length, dst, fnLengthOffset);
            System.arraycopy(fnBytes, 0, dst, dstIndex, fnBytes.length);
            dstIndex += fnBytes.length;
        }

        SMBUtil.writeInt2(80, buffer, bufferIndex + 2);
        // Set buffer length (empty directory)
        SMBUtil.writeInt4(0, buffer, bufferIndex + 4);

        // Mock getHeaderStart
        response = spy(response);
        when(response.getHeaderStart()).thenReturn(0);

        int result = response.readBytesWireFormat(buffer, bufferIndex);

        assertEquals(8, result); // Structure size (2) + offset (2) + length (4)

        }
        dstIndex += 4;

        SMBUtil.writeInt4(this.writeFlags, dst, dstIndex);
        dstIndex += 4;

        SMBUtil.writeInt2(dstIndex - getHeaderStart(), dst, dataOffsetOffset);

        if (dstIndex + this.dataLength > dst.length) {
            throw new IllegalArgumentException(

        if (securityBufferOffset < 0) {
            throw new SMBProtocolDecodingException("Invalid security buffer offset: " + securityBufferOffset + " (must be non-negative)");
        }

        final int hdrStart = getHeaderStart();
        if (securityBufferLength > 0) {
            // Validate that security buffer doesn't exceed available data
            if (hdrStart + securityBufferOffset < hdrStart || // Check for integer overflow

        bufferIndex += 4;

        if (createContextOffset > 0 && createContextLength > 0) {
            final List<CreateContextResponse> contexts = new LinkedList<>();
            int createContextStart = getHeaderStart() + createContextOffset;
            int next = 0;
            do {
                int cci = createContextStart;
                next = SMBUtil.readInt4(buffer, cci);
                cci += 4;

        request.setInfo(mockInfo);

        // Set up header start for offset calculation
        try {
            Method getHeaderStartMethod = ServerMessageBlock2.class.getDeclaredMethod("getHeaderStart");
            getHeaderStartMethod.setAccessible(true);

            // Create a buffer and write
            byte[] buffer = new byte[256];
            int bytesWritten = request.writeBytesWireFormat(buffer, 64);