~ubuntu-branches/debian/experimental/libav/experimental

/*

 * Copyright (c) 2003-2010 Michael Niedermayer <michaelni@gmx.at>

 *

 * This file is part of Libav.

 *

 * Libav is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * Libav is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with Libav; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * Accelerated start code search function for start codes common to

 * MPEG-1/2/4 video, VC-1, H.264/5

 * @author Michael Niedermayer <michaelni@gmx.at>

 */

#include "startcode.h"

#include "config.h"

int ff_startcode_find_candidate_c(const uint8_t *buf, int size)

{

    int i = 0;

#if HAVE_FAST_UNALIGNED

    /* we check i < size instead of i + 3 / 7 because it is

     * simpler and there must be FF_INPUT_BUFFER_PADDING_SIZE

     * bytes at the end.

     */

#if HAVE_FAST_64BIT

    while (i < size &&

            !((~*(const uint64_t *)(buf + i) &

                    (*(const uint64_t *)(buf + i) - 0x0101010101010101ULL)) &

                    0x8080808080808080ULL))

        i += 8;

#else

    while (i < size &&

            !((~*(const uint32_t *)(buf + i) &

                    (*(const uint32_t *)(buf + i) - 0x01010101U)) &

                    0x80808080U))

        i += 4;

#endif

#endif

    for (; i < size; i++)

        if (!buf[i])

            break;

    return i;

}