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Diffstat (limited to 'libavcodec/startcode.c')
-rw-r--r-- | libavcodec/startcode.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/libavcodec/startcode.c b/libavcodec/startcode.c new file mode 100644 index 0000000..5df7695 --- /dev/null +++ b/libavcodec/startcode.c @@ -0,0 +1,57 @@ +/* + * Copyright (c) 2003-2010 Michael Niedermayer <michaelni@gmx.at> + * + * This file is part of FFmpeg. + * + * FFmpeg 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. + * + * FFmpeg 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 FFmpeg; 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; +} |