/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*

 * This file is part of the LibreOffice project.

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 * This file incorporates work covered by the following license notice:

 *

 *   Licensed to the Apache Software Foundation (ASF) under one or more

 *   contributor license agreements. See the NOTICE file distributed

 *   with this work for additional information regarding copyright

 *   ownership. The ASF licenses this file to you under the Apache

 *   License, Version 2.0 (the "License"); you may not use this file

 *   except in compliance with the License. You may obtain a copy of

 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .

 */

#include <sal/types.h>

#include <rtl/crc.h>

#include <cassert>

#include <zlib.h>

// Zlib's crc32() is very fast, so simply use that one instead

// of implementing this ourselves.

sal_uInt32 SAL_CALL rtl_crc32 (

    sal_uInt32  Crc,

    const void *Data, sal_uInt32 DatLen) noexcept

{

    // Check that our types map to zlib correctly.

    static_assert(sizeof(uLong) >= sizeof(sal_uInt32));

    static_assert(sizeof(uInt) >= sizeof(sal_uInt32));

    // Our API says that Crc should be initialized to 0, while

    // zlib says it should be initialized with 'crc32(0,Z_NULL,0)',

    // which however simply returns 0. Ensure this.

    assert(crc32(0, Z_NULL, 0) == 0);

    if (Data)

        Crc = crc32( Crc, static_cast<const Bytef*>(Data), DatLen);

    return Crc;

}

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