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Diffstat (limited to 'src/libFLAC/bitmath.c')
-rw-r--r-- | src/libFLAC/bitmath.c | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/src/libFLAC/bitmath.c b/src/libFLAC/bitmath.c new file mode 100644 index 0000000..077486b --- /dev/null +++ b/src/libFLAC/bitmath.c @@ -0,0 +1,73 @@ +/* libFLAC - Free Lossless Audio Codec library + * Copyright (C) 2001-2009 Josh Coalson + * Copyright (C) 2011-2023 Xiph.Org Foundation + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * - Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * - Neither the name of the Xiph.org Foundation nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include "private/bitmath.h" + +/* An example of what FLAC__bitmath_silog2() computes: + * + * silog2(-10) = 5 + * silog2(- 9) = 5 + * silog2(- 8) = 4 + * silog2(- 7) = 4 + * silog2(- 6) = 4 + * silog2(- 5) = 4 + * silog2(- 4) = 3 + * silog2(- 3) = 3 + * silog2(- 2) = 2 + * silog2(- 1) = 2 + * silog2( 0) = 0 + * silog2( 1) = 2 + * silog2( 2) = 3 + * silog2( 3) = 3 + * silog2( 4) = 4 + * silog2( 5) = 4 + * silog2( 6) = 4 + * silog2( 7) = 4 + * silog2( 8) = 5 + * silog2( 9) = 5 + * silog2( 10) = 5 + */ +uint32_t FLAC__bitmath_silog2(FLAC__int64 v) +{ + if(v == 0) + return 0; + + if(v == -1) + return 2; + + v = (v < 0) ? (-(v+1)) : v; + return FLAC__bitmath_ilog2_wide(v)+2; +} |