diff options
Diffstat (limited to 'lib/rbcodec/codecs/libffmpegFLAC/golomb.h')
-rw-r--r-- | lib/rbcodec/codecs/libffmpegFLAC/golomb.h | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/libffmpegFLAC/golomb.h b/lib/rbcodec/codecs/libffmpegFLAC/golomb.h new file mode 100644 index 0000000000..197b78ee1c --- /dev/null +++ b/lib/rbcodec/codecs/libffmpegFLAC/golomb.h @@ -0,0 +1,110 @@ +/* + * exp golomb vlc stuff + * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> + * Copyright (c) 2004 Alex Beregszaszi + * + * This library 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 of the License, or (at your option) any later version. + * + * This library 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 this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + */ + +#include <limits.h> +#include "codeclib.h" + +/** + * @file golomb.h + * @brief + * exp golomb vlc stuff + * @author Michael Niedermayer <michaelni@gmx.at> and Alex Beregszaszi + */ + + +/** + * read unsigned golomb rice code (jpegls). + */ +static inline int get_ur_golomb_jpegls(GetBitContext *gb, int k, int limit, int esc_len){ + unsigned int buf; + int log; + + OPEN_READER(re, gb); + UPDATE_CACHE(re, gb); + buf=GET_CACHE(re, gb); + + log= av_log2(buf); + + if(log - k >= 32-MIN_CACHE_BITS+(MIN_CACHE_BITS==32) && 32-log < limit){ + buf >>= log - k; + buf += (30-log)<<k; + LAST_SKIP_BITS(re, gb, 32 + k - log); + CLOSE_READER(re, gb); + + return buf; + }else{ + int i; + for(i=0; SHOW_UBITS(re, gb, 1) == 0; i++){ + LAST_SKIP_BITS(re, gb, 1); + UPDATE_CACHE(re, gb); + } + SKIP_BITS(re, gb, 1); + + if(i < limit - 1){ + if(k){ + buf = SHOW_UBITS(re, gb, k); + LAST_SKIP_BITS(re, gb, k); + }else{ + buf=0; + } + + CLOSE_READER(re, gb); + return buf + (i<<k); + }else if(i == limit - 1){ + buf = SHOW_UBITS(re, gb, esc_len); + LAST_SKIP_BITS(re, gb, esc_len); + CLOSE_READER(re, gb); + + return buf + 1; + }else + return -1; + } +} + +/** + * read signed golomb rice code (flac). + */ +static inline int get_sr_golomb_flac(GetBitContext *gb, int k, int limit, int esc_len){ + int v= get_ur_golomb_jpegls(gb, k, limit, esc_len); + return (v>>1) ^ -(v&1); +} + +/** + * read unsigned golomb rice code (shorten). + */ +#define get_ur_golomb_shorten(gb, k) get_ur_golomb_jpegls(gb, k, INT_MAX, 0) +/* +static inline unsigned int get_ur_golomb_shorten(GetBitContext *gb, int k){ + return get_ur_golomb_jpegls(gb, k, INT_MAX, 0); +} +*/ + +/** + * read signed golomb rice code (shorten). + */ +static inline int get_sr_golomb_shorten(GetBitContext* gb, int k) +{ + int uvar = get_ur_golomb_jpegls(gb, k + 1, INT_MAX, 0); + if (uvar & 1) + return ~(uvar >> 1); + else + return uvar >> 1; +} |