lavu: add av_ctz() for trailing zero bit count

Justin Ruggles committed 14 years ago

Commit dfde8a31 parent 6a744d25 files · +65 −2Browse files

Unified · Split

5 files

@@ -13,6 +13,9 @@ libavutil: 2012-10-22 · 12 unmodified lines
13	13
14	14	API changes, most recent first:
15	15
	16	+2012-xx-xx - xxxxxxx - lavu 52.1.0 - intmath.h
	17	+ Add av_ctz() for trailing zero bit count
	18	+
16	19	2012-10-18 - xxxxxxx - lavu 51.45.0 - error.h
17	20	Add AVERROR_EXPERIMENTAL
18	21

@@ -67,10 +67,10 @@ OBJS = adler32.o \ · 66 unmodified lines
67	67	float_dsp.o \
68	68	imgutils.o \
69	69	intfloat_readwrite.o \
	70	+ intmath.o \
70	71	lfg.o \
71	72	lls.o \
72	73	log.o \
73		− log2.o \
74	74	log2_tab.o \
75	75	mathematics.o \
76	76	md5.o \

libavutil/intmath.crenamed from libavutil/log2.c+5−0

@@ -32,3 +32,8 @@ int av_log2_16bit(unsigned v) · 31 unmodified lines
32	32	{
33	33	return ff_log2_16bit(v);
34	34	}
	35	+
	36	+int av_ctz(int v)
	37	+{
	38	+ return ff_ctz(v);
	39	+}

@@ -85,6 +85,61 @@ static av_always_inline av_const int ff_log2_16bit_c(unsigned int v) · 84 unmodified lines
85	85	#define av_log2 ff_log2
86	86	#define av_log2_16bit ff_log2_16bit
87	87
	88	+/**
	89	+ * @}
	90	+ */
	91	+
	92	+/**
	93	+ * @addtogroup lavu_math
	94	+ * @{
	95	+ */
	96	+
	97	+#if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4)
	98	+#ifndef ff_ctz
	99	+#define ff_ctz(v) __builtin_ctz(v)
	100	+#endif
	101	+#endif
	102	+
	103	+#ifndef ff_ctz
	104	+#define ff_ctz ff_ctz_c
	105	+static av_always_inline av_const int ff_ctz_c(int v)
	106	+{
	107	+ int c;
	108	+
	109	+ if (v & 0x1)
	110	+ return 0;
	111	+
	112	+ c = 1;
	113	+ if (!(v & 0xffff)) {
	114	+ v >>= 16;
	115	+ c += 16;
	116	+ }
	117	+ if (!(v & 0xff)) {
	118	+ v >>= 8;
	119	+ c += 8;
	120	+ }
	121	+ if (!(v & 0xf)) {
	122	+ v >>= 4;
	123	+ c += 4;
	124	+ }
	125	+ if (!(v & 0x3)) {
	126	+ v >>= 2;
	127	+ c += 2;
	128	+ }
	129	+ c -= v & 0x1;
	130	+
	131	+ return c;
	132	+}
	133	+#endif
	134	+
	135	+/**
	136	+ * Trailing zero bit count.
	137	+ *
	138	+ * @param v input value. If v is 0, the result is undefined.
	139	+ * @return the number of trailing 0-bits
	140	+ */
	141	+int av_ctz(int v);
	142	+
88	143	/**
89	144	* @}
90	145	*/

@@ -37,7 +37,7 @@ · 36 unmodified lines
37	37	*/
38	38
39	39	#define LIBAVUTIL_VERSION_MAJOR 52
40		−#define LIBAVUTIL_VERSION_MINOR 0
	40	+#define LIBAVUTIL_VERSION_MINOR 1
41	41	#define LIBAVUTIL_VERSION_MICRO 0
42	42
43	43	#define LIBAVUTIL_VERSION_INT AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \

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