X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=bitstream.h;h=f54ae62bc6b132c26c15312e117e69508557bb6c;hp=e89ae1360d984c5979241061989153376ae80210;hb=bebb74fdee22f723755267b1e0c4b3708516e619;hpb=d4b77deab0304c7ba0a02a27b4b01e6af8334cbb diff --git a/bitstream.h b/bitstream.h index e89ae136..f54ae62b 100644 --- a/bitstream.h +++ b/bitstream.h @@ -77,9 +77,6 @@ struct vlc { SKIP_COUNTER(name, gb, num)\ }\ -/** This is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER. */ -#define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num) - /** Return the next num bits. */ #define SHOW_UBITS(name, gb, num)\ NEG_USR32(name##_cache, num) @@ -98,7 +95,7 @@ static inline unsigned int get_bits(struct getbit_context *s, int n) OPEN_READER(re, s) UPDATE_CACHE(re, s) tmp = SHOW_UBITS(re, s, n); - LAST_SKIP_BITS(re, s, n) + SKIP_COUNTER(re, s, n) CLOSE_READER(re, s) return tmp; } @@ -108,7 +105,7 @@ static inline void skip_bits(struct getbit_context *s, int n) /* gcc seems to optimize this to s->index+=n for the ALT_READER :)) */ OPEN_READER(re, s) UPDATE_CACHE(re, s) - LAST_SKIP_BITS(re, s, n) + SKIP_COUNTER(re, s, n) CLOSE_READER(re, s) } @@ -152,38 +149,41 @@ void init_vlc(struct vlc *vlc, int nb_bits, int nb_codes, const void *bits, void free_vlc(struct vlc *vlc); /** + * Parse a vlc code. + * + * \param bits The number of bits which will be read at once, must be + * identical to nb_bits in init_vlc() * - * if the vlc code is invalid and max_depth=1 than no bits will be removed - * if the vlc code is invalid and max_depth>1 than the number of bits removed - * is undefined + * \param max_depth The number of times bits bits must be read to completely + * read the longest vlc code = (max_vlc_length + bits - 1) / bits. */ -#define GET_VLC(code, name, gb, table, bits, max_depth)\ -{\ - int n, index, nb_bits;\ -\ - index= SHOW_UBITS(name, gb, bits);\ - code = table[index][0];\ - n = table[index][1];\ -\ - if(max_depth > 1 && n < 0){\ - LAST_SKIP_BITS(name, gb, bits)\ - UPDATE_CACHE(name, gb)\ -\ - nb_bits = -n;\ -\ - index= SHOW_UBITS(name, gb, nb_bits) + code;\ - code = table[index][0];\ - n = table[index][1];\ - if(max_depth > 2 && n < 0){\ - LAST_SKIP_BITS(name, gb, nb_bits)\ - UPDATE_CACHE(name, gb)\ -\ - nb_bits = -n;\ -\ - index= SHOW_UBITS(name, gb, nb_bits) + code;\ - code = table[index][0];\ - n = table[index][1];\ - }\ - }\ - SKIP_BITS(name, gb, n)\ +static inline int get_vlc(struct getbit_context *gb, VLC_TYPE(*table)[2], + int bits, int max_depth) +{ + int n, idx, nb_bits, code; + + OPEN_READER(re, gb) + UPDATE_CACHE(re, gb) + idx = SHOW_UBITS(re, gb, bits); + code = table[idx][0]; + n = table[idx][1]; + if (max_depth > 1 && n < 0) { + SKIP_COUNTER(re, gb, bits) + UPDATE_CACHE(re, gb) + nb_bits = -n; + idx = SHOW_UBITS(re, gb, nb_bits) + code; + code = table[idx][0]; + n = table[idx][1]; + if (max_depth > 2 && n < 0) { + SKIP_COUNTER(re, gb, nb_bits) + UPDATE_CACHE(re, gb) + nb_bits = -n; + idx = SHOW_UBITS(re, gb, nb_bits) + code; + code = table[idx][0]; + n = table[idx][1]; + } + } + SKIP_BITS(re, gb, n) + CLOSE_READER(re, gb) + return code; }