ref: 8499401ada316f99d5ea8ef058ca1669468e6a7a
dir: /sys/src/cmd/audio/libFLAC/bitmath.c/
/* libFLAC - Free Lossless Audio Codec library * Copyright (C) 2001-2009 Josh Coalson * Copyright (C) 2011-2016 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; }