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authorMåns Rullgård <mans@mansr.com>2010-03-08 21:19:56 +0000
committerMåns Rullgård <mans@mansr.com>2010-03-08 21:19:56 +0000
commit94ca624fbcaf0cd3e03ff3529453fd7a8af2c5ed (patch)
treeed6f445cfc0be488f83891b337292c01821b914c /libavutil/intmath.h
parentd73a458f279f1918a08d06b0dd43a798a71b2f74 (diff)
downloadffmpeg-94ca624fbcaf0cd3e03ff3529453fd7a8af2c5ed.tar.gz
Move ff_sqrt() to libavutil/intmath.h
Originally committed as revision 22345 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavutil/intmath.h')
-rw-r--r--libavutil/intmath.h22
1 files changed, 22 insertions, 0 deletions
diff --git a/libavutil/intmath.h b/libavutil/intmath.h
index 7aff78ceb1..02870cb282 100644
--- a/libavutil/intmath.h
+++ b/libavutil/intmath.h
@@ -56,4 +56,26 @@ extern const uint32_t ff_inverse[257];
#endif /* FASTDIV */
+extern const uint8_t ff_sqrt_tab[256];
+
+static inline av_const unsigned int ff_sqrt(unsigned int a)
+{
+ unsigned int b;
+
+ if (a < 255) return (ff_sqrt_tab[a + 1] - 1) >> 4;
+ else if (a < (1 << 12)) b = ff_sqrt_tab[a >> 4] >> 2;
+#if !CONFIG_SMALL
+ else if (a < (1 << 14)) b = ff_sqrt_tab[a >> 6] >> 1;
+ else if (a < (1 << 16)) b = ff_sqrt_tab[a >> 8] ;
+#endif
+ else {
+ int s = av_log2_16bit(a >> 16) >> 1;
+ unsigned int c = a >> (s + 2);
+ b = ff_sqrt_tab[c >> (s + 8)];
+ b = FASTDIV(c,b) + (b << s);
+ }
+
+ return b - (a < b * b);
+}
+
#endif /* AVUTIL_INTMATH_H */