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avcodec/golomb: simplify sign conversion

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Signed-off-by: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
zhaoxiu.zeng 2015-02-14 00:58:58 +08:00 committed by Michael Niedermayer
parent 0073c8e345
commit b11a187575
1 changed files with 13 additions and 28 deletions
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41
libavcodec/golomb.h
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@ -195,7 +195,7 @@ static inline int get_se_golomb(GetBitContext *gb)
return ff_se_golomb_vlc_code[buf]; return ff_se_golomb_vlc_code[buf];
} else { } else {
int log = av_log2(buf); int log = av_log2(buf), sign;
LAST_SKIP_BITS(re, gb, 31 - log); LAST_SKIP_BITS(re, gb, 31 - log);
UPDATE_CACHE(re, gb); UPDATE_CACHE(re, gb);
buf = GET_CACHE(re, gb); buf = GET_CACHE(re, gb);
@ -205,10 +205,8 @@ static inline int get_se_golomb(GetBitContext *gb)
LAST_SKIP_BITS(re, gb, 32 - log); LAST_SKIP_BITS(re, gb, 32 - log);
CLOSE_READER(re, gb); CLOSE_READER(re, gb);
if (buf & 1) sign = -(buf & 1);
buf = -(buf >> 1); buf = ((buf >> 1) ^ sign) - sign;
else
buf = (buf >> 1);
return buf; return buf;
} }
@ -217,13 +215,10 @@ static inline int get_se_golomb(GetBitContext *gb)
static inline int get_se_golomb_long(GetBitContext *gb) static inline int get_se_golomb_long(GetBitContext *gb)
{ {
unsigned int buf = get_ue_golomb_long(gb); unsigned int buf = get_ue_golomb_long(gb);
int sign;
if (buf & 1) sign = (buf & 1) - 1;
buf = (buf + 1) >> 1; return ((buf >> 1) ^ sign) + 1;
else
buf = -(buf >> 1);
return buf;
} }
static inline int svq3_get_se_golomb(GetBitContext *gb) static inline int svq3_get_se_golomb(GetBitContext *gb)
@ -264,13 +259,9 @@ static inline int dirac_get_se_golomb(GetBitContext *gb)
uint32_t ret = svq3_get_ue_golomb(gb); uint32_t ret = svq3_get_ue_golomb(gb);
if (ret) { if (ret) {
uint32_t buf; int sign;
OPEN_READER(re, gb); sign = -get_bits1(gb);
UPDATE_CACHE(re, gb); ret = (ret ^ sign) - sign;
buf = SHOW_SBITS(re, gb, 1);
LAST_SKIP_BITS(re, gb, 1);
ret = (ret ^ buf) - buf;
CLOSE_READER(re, gb);
} }
return ret; return ret;
@ -372,14 +363,11 @@ static inline int get_sr_golomb(GetBitContext *gb, int k, int limit,
int esc_len) int esc_len)
{ {
int v = get_ur_golomb(gb, k, limit, esc_len); int v = get_ur_golomb(gb, k, limit, esc_len);
int sign;
v++; v++;
if (v & 1) sign = (v & 1) - 1;
return v >> 1; return ((v >> 1) ^ sign) - sign;
else
return -(v >> 1);
// return (v>>1) ^ -(v&1);
} }
/** /**
@ -406,10 +394,7 @@ static inline unsigned int get_ur_golomb_shorten(GetBitContext *gb, int k)
static inline int get_sr_golomb_shorten(GetBitContext *gb, int k) static inline int get_sr_golomb_shorten(GetBitContext *gb, int k)
{ {
int uvar = get_ur_golomb_jpegls(gb, k + 1, INT_MAX, 0); int uvar = get_ur_golomb_jpegls(gb, k + 1, INT_MAX, 0);
if (uvar & 1) return (uvar >> 1) ^ -(uvar & 1);
return ~(uvar >> 1);
else
return uvar >> 1;
} }
#ifdef TRACE #ifdef TRACE