diff options
Diffstat (limited to 'libavcodec/get_bits.h')
-rw-r--r-- | libavcodec/get_bits.h | 158 |
1 files changed, 121 insertions, 37 deletions
diff --git a/libavcodec/get_bits.h b/libavcodec/get_bits.h index b225c13..56ef5f0 100644 --- a/libavcodec/get_bits.h +++ b/libavcodec/get_bits.h @@ -1,20 +1,20 @@ /* * copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at> * - * This file is part of Libav. + * This file is part of FFmpeg. * - * Libav is free software; you can redistribute it and/or + * 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. * - * Libav is distributed in the hope that it will be useful, + * 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 Libav; if not, write to the Free Software + * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ @@ -31,6 +31,8 @@ #include "libavutil/common.h" #include "libavutil/intreadwrite.h" #include "libavutil/log.h" +#include "libavutil/avassert.h" +#include "avcodec.h" #include "mathops.h" #include "vlc.h" @@ -55,9 +57,7 @@ typedef struct GetBitContext { const uint8_t *buffer, *buffer_end; int index; int size_in_bits; -#if !UNCHECKED_BITSTREAM_READER int size_in_bits_plus8; -#endif } GetBitContext; /* Bitstream reader API docs: @@ -101,6 +101,9 @@ typedef struct GetBitContext { * LAST_SKIP_BITS(name, gb, num) * Like SKIP_BITS, to be used if next call is UPDATE_CACHE or CLOSE_READER. * + * BITS_LEFT(name, gb) + * Return the number of bits left + * * For examples see get_bits, show_bits, skip_bits, get_vlc. */ @@ -112,7 +115,7 @@ typedef struct GetBitContext { #define OPEN_READER_NOSIZE(name, gb) \ unsigned int name ## _index = (gb)->index; \ - unsigned int av_unused name ## _cache = 0 + unsigned int av_unused name ## _cache #if UNCHECKED_BITSTREAM_READER #define OPEN_READER(name, gb) OPEN_READER_NOSIZE(name, gb) @@ -128,27 +131,34 @@ typedef struct GetBitContext { #define CLOSE_READER(name, gb) (gb)->index = name ## _index +# ifdef LONG_BITSTREAM_READER + +# define UPDATE_CACHE_LE(name, gb) name ## _cache = \ + AV_RL64((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7) + +# define UPDATE_CACHE_BE(name, gb) name ## _cache = \ + AV_RB64((gb)->buffer + (name ## _index >> 3)) >> (32 - (name ## _index & 7)) + +#else + +# define UPDATE_CACHE_LE(name, gb) name ## _cache = \ + AV_RL32((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7) + +# define UPDATE_CACHE_BE(name, gb) name ## _cache = \ + AV_RB32((gb)->buffer + (name ## _index >> 3)) << (name ## _index & 7) + +#endif + + #ifdef BITSTREAM_READER_LE -# ifdef LONG_BITSTREAM_READER -# define UPDATE_CACHE(name, gb) name ## _cache = \ - AV_RL64((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7) -# else -# define UPDATE_CACHE(name, gb) name ## _cache = \ - AV_RL32((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7) -# endif +# define UPDATE_CACHE(name, gb) UPDATE_CACHE_LE(name, gb) # define SKIP_CACHE(name, gb, num) name ## _cache >>= (num) #else -# ifdef LONG_BITSTREAM_READER -# define UPDATE_CACHE(name, gb) name ## _cache = \ - AV_RB64((gb)->buffer + (name ## _index >> 3)) >> (32 - (name ## _index & 7)) -# else -# define UPDATE_CACHE(name, gb) name ## _cache = \ - AV_RB32((gb)->buffer + (name ## _index >> 3)) << (name ## _index & 7) -# endif +# define UPDATE_CACHE(name, gb) UPDATE_CACHE_BE(name, gb) # define SKIP_CACHE(name, gb, num) name ## _cache <<= (num) @@ -161,6 +171,8 @@ typedef struct GetBitContext { name ## _index = FFMIN(name ## _size_plus8, name ## _index + (num)) #endif +#define BITS_LEFT(name, gb) ((int)((gb)->size_in_bits - name ## _index)) + #define SKIP_BITS(name, gb, num) \ do { \ SKIP_CACHE(name, gb, num); \ @@ -169,12 +181,18 @@ typedef struct GetBitContext { #define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num) +#define SHOW_UBITS_LE(name, gb, num) zero_extend(name ## _cache, num) +#define SHOW_SBITS_LE(name, gb, num) sign_extend(name ## _cache, num) + +#define SHOW_UBITS_BE(name, gb, num) NEG_USR32(name ## _cache, num) +#define SHOW_SBITS_BE(name, gb, num) NEG_SSR32(name ## _cache, num) + #ifdef BITSTREAM_READER_LE -# define SHOW_UBITS(name, gb, num) zero_extend(name ## _cache, num) -# define SHOW_SBITS(name, gb, num) sign_extend(name ## _cache, num) +# define SHOW_UBITS(name, gb, num) SHOW_UBITS_LE(name, gb, num) +# define SHOW_SBITS(name, gb, num) SHOW_SBITS_LE(name, gb, num) #else -# define SHOW_UBITS(name, gb, num) NEG_USR32(name ## _cache, num) -# define SHOW_SBITS(name, gb, num) NEG_SSR32(name ## _cache, num) +# define SHOW_UBITS(name, gb, num) SHOW_UBITS_BE(name, gb, num) +# define SHOW_SBITS(name, gb, num) SHOW_SBITS_BE(name, gb, num) #endif #define GET_CACHE(name, gb) ((uint32_t) name ## _cache) @@ -184,6 +202,13 @@ static inline int get_bits_count(const GetBitContext *s) return s->index; } +/** + * Skips the specified number of bits. + * @param n the number of bits to skip, + * For the UNCHECKED_BITSTREAM_READER this must not cause the distance + * from the start to overflow int32_t. Staying within the bitstream + padding + * is sufficient, too. + */ static inline void skip_bits_long(GetBitContext *s, int n) { #if UNCHECKED_BITSTREAM_READER @@ -194,7 +219,7 @@ static inline void skip_bits_long(GetBitContext *s, int n) } /** - * Read MPEG-1 dc-style VLC (sign bit + mantisse with no MSB). + * Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB). * if MSB not set it is negative * @param n length in bits */ @@ -203,6 +228,7 @@ static inline int get_xbits(GetBitContext *s, int n) register int sign; register int32_t cache; OPEN_READER(re, s); + av_assert2(n>0 && n<=25); UPDATE_CACHE(re, s); cache = GET_CACHE(re, s); sign = ~cache >> 31; @@ -211,10 +237,25 @@ static inline int get_xbits(GetBitContext *s, int n) return (NEG_USR32(sign ^ cache, n) ^ sign) - sign; } +static inline int get_xbits_le(GetBitContext *s, int n) +{ + register int sign; + register int32_t cache; + OPEN_READER(re, s); + av_assert2(n>0 && n<=25); + UPDATE_CACHE_LE(re, s); + cache = GET_CACHE(re, s); + sign = sign_extend(~cache, n) >> 31; + LAST_SKIP_BITS(re, s, n); + CLOSE_READER(re, s); + return (zero_extend(sign ^ cache, n) ^ sign) - sign; +} + static inline int get_sbits(GetBitContext *s, int n) { register int tmp; OPEN_READER(re, s); + av_assert2(n>0 && n<=25); UPDATE_CACHE(re, s); tmp = SHOW_SBITS(re, s, n); LAST_SKIP_BITS(re, s, n); @@ -229,6 +270,7 @@ static inline unsigned int get_bits(GetBitContext *s, int n) { register int tmp; OPEN_READER(re, s); + av_assert2(n>0 && n<=25); UPDATE_CACHE(re, s); tmp = SHOW_UBITS(re, s, n); LAST_SKIP_BITS(re, s, n); @@ -244,6 +286,18 @@ static av_always_inline int get_bitsz(GetBitContext *s, int n) return n ? get_bits(s, n) : 0; } +static inline unsigned int get_bits_le(GetBitContext *s, int n) +{ + register int tmp; + OPEN_READER(re, s); + av_assert2(n>0 && n<=25); + UPDATE_CACHE_LE(re, s); + tmp = SHOW_UBITS_LE(re, s, n); + LAST_SKIP_BITS(re, s, n); + CLOSE_READER(re, s); + return tmp; +} + /** * Show 1-25 bits. */ @@ -251,6 +305,7 @@ static inline unsigned int show_bits(GetBitContext *s, int n) { register int tmp; OPEN_READER_NOSIZE(re, s); + av_assert2(n>0 && n<=25); UPDATE_CACHE(re, s); tmp = SHOW_UBITS(re, s, n); return tmp; @@ -259,7 +314,6 @@ static inline unsigned int show_bits(GetBitContext *s, int n) static inline void skip_bits(GetBitContext *s, int n) { OPEN_READER(re, s); - UPDATE_CACHE(re, s); LAST_SKIP_BITS(re, s, n); CLOSE_READER(re, s); } @@ -299,20 +353,23 @@ static inline void skip_bits1(GetBitContext *s) */ static inline unsigned int get_bits_long(GetBitContext *s, int n) { - if (n <= MIN_CACHE_BITS) { + av_assert2(n>=0 && n<=32); + if (!n) { + return 0; + } else if (n <= MIN_CACHE_BITS) { return get_bits(s, n); } else { #ifdef BITSTREAM_READER_LE - int ret = get_bits(s, 16); + unsigned ret = get_bits(s, 16); return ret | (get_bits(s, n - 16) << 16); #else - int ret = get_bits(s, 16) << (n - 16); + unsigned ret = get_bits(s, 16) << (n - 16); return ret | get_bits(s, n - 16); #endif } } -/* +/** * Read 0-64 bits. */ static inline uint64_t get_bits64(GetBitContext *s, int n) @@ -335,6 +392,10 @@ static inline uint64_t get_bits64(GetBitContext *s, int n) */ static inline int get_sbits_long(GetBitContext *s, int n) { + // sign_extend(x, 0) is undefined + if (!n) + return 0; + return sign_extend(get_bits_long(s, n), n); } @@ -351,6 +412,16 @@ static inline unsigned int show_bits_long(GetBitContext *s, int n) } } +static inline int check_marker(void *logctx, GetBitContext *s, const char *msg) +{ + int bit = get_bits1(s); + if (!bit) + av_log(logctx, AV_LOG_INFO, "Marker bit missing at %d of %d %s\n", + get_bits_count(s) - 1, s->size_in_bits, msg); + + return bit; +} + /** * Initialize GetBitContext. * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes @@ -365,7 +436,7 @@ static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer, int buffer_size; int ret = 0; - if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) { + if (bit_size >= INT_MAX - FFMAX(7, AV_INPUT_BUFFER_PADDING_SIZE*8) || bit_size < 0 || !buffer) { bit_size = 0; buffer = NULL; ret = AVERROR_INVALIDDATA; @@ -375,9 +446,7 @@ static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer, s->buffer = buffer; s->size_in_bits = bit_size; -#if !UNCHECKED_BITSTREAM_READER s->size_in_bits_plus8 = bit_size + 8; -#endif s->buffer_end = buffer + buffer_size; s->index = 0; @@ -395,8 +464,8 @@ static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer, static inline int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size) { - if (byte_size > INT_MAX / 8) - return AVERROR_INVALIDDATA; + if (byte_size > INT_MAX / 8 || byte_size < 0) + byte_size = -1; return init_get_bits(s, buffer, byte_size * 8); } @@ -445,7 +514,7 @@ static inline const uint8_t *align_get_bits(GetBitContext *s) SKIP_BITS(name, gb, n); \ } while (0) -#define GET_RL_VLC(level, run, name, gb, table, bits, \ +#define GET_RL_VLC(level, run, name, gb, table, bits, \ max_depth, need_update) \ do { \ int n, nb_bits; \ @@ -489,6 +558,7 @@ static inline const uint8_t *align_get_bits(GetBitContext *s) * @param max_depth is the number of times bits bits must be read to completely * read the longest vlc code * = (max_vlc_length + bits - 1) / bits + * @returns the code parsed or -1 if no vlc matches */ static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth) @@ -528,4 +598,18 @@ static inline int get_bits_left(GetBitContext *gb) return gb->size_in_bits - get_bits_count(gb); } +static inline int skip_1stop_8data_bits(GetBitContext *gb) +{ + if (get_bits_left(gb) <= 0) + return AVERROR_INVALIDDATA; + + while (get_bits1(gb)) { + skip_bits(gb, 8); + if (get_bits_left(gb) <= 0) + return AVERROR_INVALIDDATA; + } + + return 0; +} + #endif /* AVCODEC_GET_BITS_H */ |