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58 lines
1.8 KiB
58 lines
1.8 KiB
10 years ago
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/*
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* Copyright (c) 2003-2010 Michael Niedermayer <michaelni@gmx.at>
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Accelerated start code search function for start codes common to
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* MPEG-1/2/4 video, VC-1, H.264/5
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* @author Michael Niedermayer <michaelni@gmx.at>
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*/
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#include "startcode.h"
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#include "config.h"
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int ff_startcode_find_candidate_c(const uint8_t *buf, int size)
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{
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int i = 0;
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#if HAVE_FAST_UNALIGNED
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/* we check i < size instead of i + 3 / 7 because it is
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* simpler and there must be FF_INPUT_BUFFER_PADDING_SIZE
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* bytes at the end.
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*/
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#if HAVE_FAST_64BIT
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while (i < size &&
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!((~*(const uint64_t *)(buf + i) &
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(*(const uint64_t *)(buf + i) - 0x0101010101010101ULL)) &
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0x8080808080808080ULL))
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i += 8;
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#else
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while (i < size &&
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!((~*(const uint32_t *)(buf + i) &
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(*(const uint32_t *)(buf + i) - 0x01010101U)) &
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0x80808080U))
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i += 4;
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#endif
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#endif
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for (; i < size; i++)
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if (!buf[i])
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break;
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return i;
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}
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