mirror of
https://gitee.com/Vancouver2017/luban-lite-t3e-pro.git
synced 2025-12-14 10:28:54 +00:00
116 lines
3.7 KiB
C
116 lines
3.7 KiB
C
/* libFLAC - Free Lossless Audio Codec library
|
|
* Copyright (C) 2001-2009 Josh Coalson
|
|
* Copyright (C) 2011-2024 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;
|
|
}
|
|
|
|
/* An example of what FLAC__bitmath_extra_mulbits_unsigned() computes:
|
|
*
|
|
* extra_mulbits_unsigned( 0) = 0
|
|
* extra_mulbits_unsigned( 1) = 0
|
|
* extra_mulbits_unsigned( 2) = 1
|
|
* extra_mulbits_unsigned( 3) = 2
|
|
* extra_mulbits_unsigned( 4) = 2
|
|
* extra_mulbits_unsigned( 5) = 3
|
|
* extra_mulbits_unsigned( 6) = 3
|
|
* extra_mulbits_unsigned( 7) = 3
|
|
* extra_mulbits_unsigned( 8) = 3
|
|
* extra_mulbits_unsigned( 9) = 4
|
|
* extra_mulbits_unsigned(10) = 4
|
|
* extra_mulbits_unsigned(11) = 4
|
|
* extra_mulbits_unsigned(12) = 4
|
|
* extra_mulbits_unsigned(13) = 4
|
|
* extra_mulbits_unsigned(14) = 4
|
|
* extra_mulbits_unsigned(15) = 4
|
|
* extra_mulbits_unsigned(16) = 4
|
|
* extra_mulbits_unsigned(17) = 5
|
|
* extra_mulbits_unsigned(18) = 5
|
|
*
|
|
* The intent of this is to calculate how many extra bits multiplication
|
|
* by a certain number requires. So, if a signal fits in a certain number
|
|
* of bits (for example 16) than multiplying by a number (for example 1024)
|
|
* grows that storage requirement (to 26 in this example). In effect this is
|
|
* is the log2 rounded up.
|
|
*/
|
|
uint32_t FLAC__bitmath_extra_mulbits_unsigned(FLAC__uint32 v)
|
|
{
|
|
uint32_t ilog2;
|
|
if(v == 0)
|
|
return 0;
|
|
ilog2 = FLAC__bitmath_ilog2(v);
|
|
if(((v >> ilog2) << ilog2) == v)
|
|
/* v is power of 2 */
|
|
return ilog2;
|
|
else
|
|
/* v is not a power of 2, return one higher */
|
|
return ilog2 + 1;
|
|
}
|