libFLAC/float.c - platform/external/flac - Git at Google

 /* libFLAC - Free Lossless Audio Codec library
  * Copyright (C) 2004,2005,2006,2007  Josh Coalson
  *
  * 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.
  */

 #if HAVE_CONFIG_H
 #  include <config.h>
 #endif

 #include "FLAC/assert.h"

 #include "private/float.h"

 #ifdef FLAC__INTEGER_ONLY_LIBRARY

 /* adjust for compilers that can't understand using LLU suffix for uint64_t literals */
 #ifdef _MSC_VER
 #define FLAC__U64L(x) x
 #else
 #define FLAC__U64L(x) x##LLU
 #endif

 const FLAC__fixedpoint FLAC__FP_ZERO = 0;
 const FLAC__fixedpoint FLAC__FP_ONE_HALF = 0x00008000;
 const FLAC__fixedpoint FLAC__FP_ONE = 0x00010000;
 const FLAC__fixedpoint FLAC__FP_LN2 = 45426;
 const FLAC__fixedpoint FLAC__FP_E = 178145;

 /* Lookup tables for Knuth's logarithm algorithm */
 #define LOG2_LOOKUP_PRECISION 16
 static const FLAC__uint32 log2_lookup[][LOG2_LOOKUP_PRECISION] = {
 	{
 		/*
 		 * 0 fraction bits
 		 */
 		/* undefined */ 0x00000000,
 		/* lg(2/1) = */ 0x00000001,
 		/* lg(4/3) = */ 0x00000000,
 		/* lg(8/7) = */ 0x00000000,
 		/* lg(16/15) = */ 0x00000000,
 		/* lg(32/31) = */ 0x00000000,
 		/* lg(64/63) = */ 0x00000000,
 		/* lg(128/127) = */ 0x00000000,
 		/* lg(256/255) = */ 0x00000000,
 		/* lg(512/511) = */ 0x00000000,
 		/* lg(1024/1023) = */ 0x00000000,
 		/* lg(2048/2047) = */ 0x00000000,
 		/* lg(4096/4095) = */ 0x00000000,
 		/* lg(8192/8191) = */ 0x00000000,
 		/* lg(16384/16383) = */ 0x00000000,
 		/* lg(32768/32767) = */ 0x00000000
 	},
 	{
 		/*
 		 * 4 fraction bits
 		 */
 		/* undefined */ 0x00000000,
 		/* lg(2/1) = */ 0x00000010,
 		/* lg(4/3) = */ 0x00000007,
 		/* lg(8/7) = */ 0x00000003,
 		/* lg(16/15) = */ 0x00000001,
 		/* lg(32/31) = */ 0x00000001,
 		/* lg(64/63) = */ 0x00000000,
 		/* lg(128/127) = */ 0x00000000,
 		/* lg(256/255) = */ 0x00000000,
 		/* lg(512/511) = */ 0x00000000,
 		/* lg(1024/1023) = */ 0x00000000,
 		/* lg(2048/2047) = */ 0x00000000,
 		/* lg(4096/4095) = */ 0x00000000,
 		/* lg(8192/8191) = */ 0x00000000,
 		/* lg(16384/16383) = */ 0x00000000,
 		/* lg(32768/32767) = */ 0x00000000
 	},
 	{
 		/*
 		 * 8 fraction bits
 		 */
 		/* undefined */ 0x00000000,
 		/* lg(2/1) = */ 0x00000100,
 		/* lg(4/3) = */ 0x0000006a,
 		/* lg(8/7) = */ 0x00000031,
 		/* lg(16/15) = */ 0x00000018,
 		/* lg(32/31) = */ 0x0000000c,
 		/* lg(64/63) = */ 0x00000006,
 		/* lg(128/127) = */ 0x00000003,
 		/* lg(256/255) = */ 0x00000001,
 		/* lg(512/511) = */ 0x00000001,
 		/* lg(1024/1023) = */ 0x00000000,
 		/* lg(2048/2047) = */ 0x00000000,
 		/* lg(4096/4095) = */ 0x00000000,
 		/* lg(8192/8191) = */ 0x00000000,
 		/* lg(16384/16383) = */ 0x00000000,
 		/* lg(32768/32767) = */ 0x00000000
 	},
 	{
 		/*
 		 * 12 fraction bits
 		 */
 		/* undefined */ 0x00000000,
 		/* lg(2/1) = */ 0x00001000,
 		/* lg(4/3) = */ 0x000006a4,
 		/* lg(8/7) = */ 0x00000315,
 		/* lg(16/15) = */ 0x0000017d,
 		/* lg(32/31) = */ 0x000000bc,
 		/* lg(64/63) = */ 0x0000005d,
 		/* lg(128/127) = */ 0x0000002e,
 		/* lg(256/255) = */ 0x00000017,
 		/* lg(512/511) = */ 0x0000000c,
 		/* lg(1024/1023) = */ 0x00000006,
 		/* lg(2048/2047) = */ 0x00000003,
 		/* lg(4096/4095) = */ 0x00000001,
 		/* lg(8192/8191) = */ 0x00000001,
 		/* lg(16384/16383) = */ 0x00000000,
 		/* lg(32768/32767) = */ 0x00000000
 	},
 	{
 		/*
 		 * 16 fraction bits
 		 */
 		/* undefined */ 0x00000000,
 		/* lg(2/1) = */ 0x00010000,
 		/* lg(4/3) = */ 0x00006a40,
 		/* lg(8/7) = */ 0x00003151,
 		/* lg(16/15) = */ 0x000017d6,
 		/* lg(32/31) = */ 0x00000bba,
 		/* lg(64/63) = */ 0x000005d1,
 		/* lg(128/127) = */ 0x000002e6,
 		/* lg(256/255) = */ 0x00000172,
 		/* lg(512/511) = */ 0x000000b9,
 		/* lg(1024/1023) = */ 0x0000005c,
 		/* lg(2048/2047) = */ 0x0000002e,
 		/* lg(4096/4095) = */ 0x00000017,
 		/* lg(8192/8191) = */ 0x0000000c,
 		/* lg(16384/16383) = */ 0x00000006,
 		/* lg(32768/32767) = */ 0x00000003
 	},
 	{
 		/*
 		 * 20 fraction bits
 		 */
 		/* undefined */ 0x00000000,
 		/* lg(2/1) = */ 0x00100000,
 		/* lg(4/3) = */ 0x0006a3fe,
 		/* lg(8/7) = */ 0x00031513,
 		/* lg(16/15) = */ 0x00017d60,
 		/* lg(32/31) = */ 0x0000bb9d,
 		/* lg(64/63) = */ 0x00005d10,
 		/* lg(128/127) = */ 0x00002e59,
 		/* lg(256/255) = */ 0x00001721,
 		/* lg(512/511) = */ 0x00000b8e,
 		/* lg(1024/1023) = */ 0x000005c6,
 		/* lg(2048/2047) = */ 0x000002e3,
 		/* lg(4096/4095) = */ 0x00000171,
 		/* lg(8192/8191) = */ 0x000000b9,
 		/* lg(16384/16383) = */ 0x0000005c,
 		/* lg(32768/32767) = */ 0x0000002e
 	},
 	{
 		/*
 		 * 24 fraction bits
 		 */
 		/* undefined */ 0x00000000,
 		/* lg(2/1) = */ 0x01000000,
 		/* lg(4/3) = */ 0x006a3fe6,
 		/* lg(8/7) = */ 0x00315130,
 		/* lg(16/15) = */ 0x0017d605,
 		/* lg(32/31) = */ 0x000bb9ca,
 		/* lg(64/63) = */ 0x0005d0fc,
 		/* lg(128/127) = */ 0x0002e58f,
 		/* lg(256/255) = */ 0x0001720e,
 		/* lg(512/511) = */ 0x0000b8d8,
 		/* lg(1024/1023) = */ 0x00005c61,
 		/* lg(2048/2047) = */ 0x00002e2d,
 		/* lg(4096/4095) = */ 0x00001716,
 		/* lg(8192/8191) = */ 0x00000b8b,
 		/* lg(16384/16383) = */ 0x000005c5,
 		/* lg(32768/32767) = */ 0x000002e3
 	},
 	{
 		/*
 		 * 28 fraction bits
 		 */
 		/* undefined */ 0x00000000,
 		/* lg(2/1) = */ 0x10000000,
 		/* lg(4/3) = */ 0x06a3fe5c,
 		/* lg(8/7) = */ 0x03151301,
 		/* lg(16/15) = */ 0x017d6049,
 		/* lg(32/31) = */ 0x00bb9ca6,
 		/* lg(64/63) = */ 0x005d0fba,
 		/* lg(128/127) = */ 0x002e58f7,
 		/* lg(256/255) = */ 0x001720da,
 		/* lg(512/511) = */ 0x000b8d87,
 		/* lg(1024/1023) = */ 0x0005c60b,
 		/* lg(2048/2047) = */ 0x0002e2d7,
 		/* lg(4096/4095) = */ 0x00017160,
 		/* lg(8192/8191) = */ 0x0000b8ad,
 		/* lg(16384/16383) = */ 0x00005c56,
 		/* lg(32768/32767) = */ 0x00002e2b
 	}
 };

 #if 0
 static const FLAC__uint64 log2_lookup_wide[] = {
 	{
 		/*
 		 * 32 fraction bits
 		 */
 		/* undefined */ 0x00000000,
 		/* lg(2/1) = */ FLAC__U64L(0x100000000),
 		/* lg(4/3) = */ FLAC__U64L(0x6a3fe5c6),
 		/* lg(8/7) = */ FLAC__U64L(0x31513015),
 		/* lg(16/15) = */ FLAC__U64L(0x17d60497),
 		/* lg(32/31) = */ FLAC__U64L(0x0bb9ca65),
 		/* lg(64/63) = */ FLAC__U64L(0x05d0fba2),
 		/* lg(128/127) = */ FLAC__U64L(0x02e58f74),
 		/* lg(256/255) = */ FLAC__U64L(0x01720d9c),
 		/* lg(512/511) = */ FLAC__U64L(0x00b8d875),
 		/* lg(1024/1023) = */ FLAC__U64L(0x005c60aa),
 		/* lg(2048/2047) = */ FLAC__U64L(0x002e2d72),
 		/* lg(4096/4095) = */ FLAC__U64L(0x00171600),
 		/* lg(8192/8191) = */ FLAC__U64L(0x000b8ad2),
 		/* lg(16384/16383) = */ FLAC__U64L(0x0005c55d),
 		/* lg(32768/32767) = */ FLAC__U64L(0x0002e2ac)
 	},
 	{
 		/*
 		 * 48 fraction bits
 		 */
 		/* undefined */ 0x00000000,
 		/* lg(2/1) = */ FLAC__U64L(0x1000000000000),
 		/* lg(4/3) = */ FLAC__U64L(0x6a3fe5c60429),
 		/* lg(8/7) = */ FLAC__U64L(0x315130157f7a),
 		/* lg(16/15) = */ FLAC__U64L(0x17d60496cfbb),
 		/* lg(32/31) = */ FLAC__U64L(0xbb9ca64ecac),
 		/* lg(64/63) = */ FLAC__U64L(0x5d0fba187cd),
 		/* lg(128/127) = */ FLAC__U64L(0x2e58f7441ee),
 		/* lg(256/255) = */ FLAC__U64L(0x1720d9c06a8),
 		/* lg(512/511) = */ FLAC__U64L(0xb8d8752173),
 		/* lg(1024/1023) = */ FLAC__U64L(0x5c60aa252e),
 		/* lg(2048/2047) = */ FLAC__U64L(0x2e2d71b0d8),
 		/* lg(4096/4095) = */ FLAC__U64L(0x1716001719),
 		/* lg(8192/8191) = */ FLAC__U64L(0xb8ad1de1b),
 		/* lg(16384/16383) = */ FLAC__U64L(0x5c55d640d),
 		/* lg(32768/32767) = */ FLAC__U64L(0x2e2abcf52)
 	}
 };
 #endif

 FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, unsigned fracbits, unsigned precision)
 {
 	const FLAC__uint32 ONE = (1u << fracbits);
 	const FLAC__uint32 *table = log2_lookup[fracbits >> 2];

 	FLAC__ASSERT(fracbits < 32);
 	FLAC__ASSERT((fracbits & 0x3) == 0);

 	if(x < ONE)
 		return 0;

 	if(precision > LOG2_LOOKUP_PRECISION)
 		precision = LOG2_LOOKUP_PRECISION;

 	/* Knuth's algorithm for computing logarithms, optimized for base-2 with lookup tables */
 	{
 		FLAC__uint32 y = 0;
 		FLAC__uint32 z = x >> 1, k = 1;
 		while (x > ONE && k < precision) {
 			if (x - z >= ONE) {
 				x -= z;
 				z = x >> k;
 				y += table[k];
 			}
 			else {
 				z >>= 1;
 				k++;
 			}
 		}
 		return y;
 	}
 }

 #endif /* defined FLAC__INTEGER_ONLY_LIBRARY */
	/* libFLAC - Free Lossless Audio Codec library
	* Copyright (C) 2004,2005,2006,2007 Josh Coalson
	*
	* 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.
	*/

	#if HAVE_CONFIG_H
	# include <config.h>
	#endif

	#include "FLAC/assert.h"

	#include "private/float.h"

	#ifdef FLAC__INTEGER_ONLY_LIBRARY

	/* adjust for compilers that can't understand using LLU suffix for uint64_t literals */
	#ifdef _MSC_VER
	#define FLAC__U64L(x) x
	#else
	#define FLAC__U64L(x) x##LLU
	#endif

	const FLAC__fixedpoint FLAC__FP_ZERO = 0;
	const FLAC__fixedpoint FLAC__FP_ONE_HALF = 0x00008000;
	const FLAC__fixedpoint FLAC__FP_ONE = 0x00010000;
	const FLAC__fixedpoint FLAC__FP_LN2 = 45426;
	const FLAC__fixedpoint FLAC__FP_E = 178145;

	/* Lookup tables for Knuth's logarithm algorithm */
	#define LOG2_LOOKUP_PRECISION 16
	static const FLAC__uint32 log2_lookup[][LOG2_LOOKUP_PRECISION] = {
	{
	/*
	* 0 fraction bits
	*/
	/* undefined */ 0x00000000,
	/* lg(2/1) = */ 0x00000001,
	/* lg(4/3) = */ 0x00000000,
	/* lg(8/7) = */ 0x00000000,
	/* lg(16/15) = */ 0x00000000,
	/* lg(32/31) = */ 0x00000000,
	/* lg(64/63) = */ 0x00000000,
	/* lg(128/127) = */ 0x00000000,
	/* lg(256/255) = */ 0x00000000,
	/* lg(512/511) = */ 0x00000000,
	/* lg(1024/1023) = */ 0x00000000,
	/* lg(2048/2047) = */ 0x00000000,
	/* lg(4096/4095) = */ 0x00000000,
	/* lg(8192/8191) = */ 0x00000000,
	/* lg(16384/16383) = */ 0x00000000,
	/* lg(32768/32767) = */ 0x00000000
	},
	{
	/*
	* 4 fraction bits
	*/
	/* undefined */ 0x00000000,
	/* lg(2/1) = */ 0x00000010,
	/* lg(4/3) = */ 0x00000007,
	/* lg(8/7) = */ 0x00000003,
	/* lg(16/15) = */ 0x00000001,
	/* lg(32/31) = */ 0x00000001,
	/* lg(64/63) = */ 0x00000000,
	/* lg(128/127) = */ 0x00000000,
	/* lg(256/255) = */ 0x00000000,
	/* lg(512/511) = */ 0x00000000,
	/* lg(1024/1023) = */ 0x00000000,
	/* lg(2048/2047) = */ 0x00000000,
	/* lg(4096/4095) = */ 0x00000000,
	/* lg(8192/8191) = */ 0x00000000,
	/* lg(16384/16383) = */ 0x00000000,
	/* lg(32768/32767) = */ 0x00000000
	},
	{
	/*
	* 8 fraction bits
	*/
	/* undefined */ 0x00000000,
	/* lg(2/1) = */ 0x00000100,
	/* lg(4/3) = */ 0x0000006a,
	/* lg(8/7) = */ 0x00000031,
	/* lg(16/15) = */ 0x00000018,
	/* lg(32/31) = */ 0x0000000c,
	/* lg(64/63) = */ 0x00000006,
	/* lg(128/127) = */ 0x00000003,
	/* lg(256/255) = */ 0x00000001,
	/* lg(512/511) = */ 0x00000001,
	/* lg(1024/1023) = */ 0x00000000,
	/* lg(2048/2047) = */ 0x00000000,
	/* lg(4096/4095) = */ 0x00000000,
	/* lg(8192/8191) = */ 0x00000000,
	/* lg(16384/16383) = */ 0x00000000,
	/* lg(32768/32767) = */ 0x00000000
	},
	{
	/*
	* 12 fraction bits
	*/
	/* undefined */ 0x00000000,
	/* lg(2/1) = */ 0x00001000,
	/* lg(4/3) = */ 0x000006a4,
	/* lg(8/7) = */ 0x00000315,
	/* lg(16/15) = */ 0x0000017d,
	/* lg(32/31) = */ 0x000000bc,
	/* lg(64/63) = */ 0x0000005d,
	/* lg(128/127) = */ 0x0000002e,
	/* lg(256/255) = */ 0x00000017,
	/* lg(512/511) = */ 0x0000000c,
	/* lg(1024/1023) = */ 0x00000006,
	/* lg(2048/2047) = */ 0x00000003,
	/* lg(4096/4095) = */ 0x00000001,
	/* lg(8192/8191) = */ 0x00000001,
	/* lg(16384/16383) = */ 0x00000000,
	/* lg(32768/32767) = */ 0x00000000
	},
	{
	/*
	* 16 fraction bits
	*/
	/* undefined */ 0x00000000,
	/* lg(2/1) = */ 0x00010000,
	/* lg(4/3) = */ 0x00006a40,
	/* lg(8/7) = */ 0x00003151,
	/* lg(16/15) = */ 0x000017d6,
	/* lg(32/31) = */ 0x00000bba,
	/* lg(64/63) = */ 0x000005d1,
	/* lg(128/127) = */ 0x000002e6,
	/* lg(256/255) = */ 0x00000172,
	/* lg(512/511) = */ 0x000000b9,
	/* lg(1024/1023) = */ 0x0000005c,
	/* lg(2048/2047) = */ 0x0000002e,
	/* lg(4096/4095) = */ 0x00000017,
	/* lg(8192/8191) = */ 0x0000000c,
	/* lg(16384/16383) = */ 0x00000006,
	/* lg(32768/32767) = */ 0x00000003
	},
	{
	/*
	* 20 fraction bits
	*/
	/* undefined */ 0x00000000,
	/* lg(2/1) = */ 0x00100000,
	/* lg(4/3) = */ 0x0006a3fe,
	/* lg(8/7) = */ 0x00031513,
	/* lg(16/15) = */ 0x00017d60,
	/* lg(32/31) = */ 0x0000bb9d,
	/* lg(64/63) = */ 0x00005d10,
	/* lg(128/127) = */ 0x00002e59,
	/* lg(256/255) = */ 0x00001721,
	/* lg(512/511) = */ 0x00000b8e,
	/* lg(1024/1023) = */ 0x000005c6,
	/* lg(2048/2047) = */ 0x000002e3,
	/* lg(4096/4095) = */ 0x00000171,
	/* lg(8192/8191) = */ 0x000000b9,
	/* lg(16384/16383) = */ 0x0000005c,
	/* lg(32768/32767) = */ 0x0000002e
	},
	{
	/*
	* 24 fraction bits
	*/
	/* undefined */ 0x00000000,
	/* lg(2/1) = */ 0x01000000,
	/* lg(4/3) = */ 0x006a3fe6,
	/* lg(8/7) = */ 0x00315130,
	/* lg(16/15) = */ 0x0017d605,
	/* lg(32/31) = */ 0x000bb9ca,
	/* lg(64/63) = */ 0x0005d0fc,
	/* lg(128/127) = */ 0x0002e58f,
	/* lg(256/255) = */ 0x0001720e,
	/* lg(512/511) = */ 0x0000b8d8,
	/* lg(1024/1023) = */ 0x00005c61,
	/* lg(2048/2047) = */ 0x00002e2d,
	/* lg(4096/4095) = */ 0x00001716,
	/* lg(8192/8191) = */ 0x00000b8b,
	/* lg(16384/16383) = */ 0x000005c5,
	/* lg(32768/32767) = */ 0x000002e3
	},
	{
	/*
	* 28 fraction bits
	*/
	/* undefined */ 0x00000000,
	/* lg(2/1) = */ 0x10000000,
	/* lg(4/3) = */ 0x06a3fe5c,
	/* lg(8/7) = */ 0x03151301,
	/* lg(16/15) = */ 0x017d6049,
	/* lg(32/31) = */ 0x00bb9ca6,
	/* lg(64/63) = */ 0x005d0fba,
	/* lg(128/127) = */ 0x002e58f7,
	/* lg(256/255) = */ 0x001720da,
	/* lg(512/511) = */ 0x000b8d87,
	/* lg(1024/1023) = */ 0x0005c60b,
	/* lg(2048/2047) = */ 0x0002e2d7,
	/* lg(4096/4095) = */ 0x00017160,
	/* lg(8192/8191) = */ 0x0000b8ad,
	/* lg(16384/16383) = */ 0x00005c56,
	/* lg(32768/32767) = */ 0x00002e2b
	}
	};

	#if 0
	static const FLAC__uint64 log2_lookup_wide[] = {
	{
	/*
	* 32 fraction bits
	*/
	/* undefined */ 0x00000000,
	/* lg(2/1) = */ FLAC__U64L(0x100000000),
	/* lg(4/3) = */ FLAC__U64L(0x6a3fe5c6),
	/* lg(8/7) = */ FLAC__U64L(0x31513015),
	/* lg(16/15) = */ FLAC__U64L(0x17d60497),
	/* lg(32/31) = */ FLAC__U64L(0x0bb9ca65),
	/* lg(64/63) = */ FLAC__U64L(0x05d0fba2),
	/* lg(128/127) = */ FLAC__U64L(0x02e58f74),
	/* lg(256/255) = */ FLAC__U64L(0x01720d9c),
	/* lg(512/511) = */ FLAC__U64L(0x00b8d875),
	/* lg(1024/1023) = */ FLAC__U64L(0x005c60aa),
	/* lg(2048/2047) = */ FLAC__U64L(0x002e2d72),
	/* lg(4096/4095) = */ FLAC__U64L(0x00171600),
	/* lg(8192/8191) = */ FLAC__U64L(0x000b8ad2),
	/* lg(16384/16383) = */ FLAC__U64L(0x0005c55d),
	/* lg(32768/32767) = */ FLAC__U64L(0x0002e2ac)
	},
	{
	/*
	* 48 fraction bits
	*/
	/* undefined */ 0x00000000,
	/* lg(2/1) = */ FLAC__U64L(0x1000000000000),
	/* lg(4/3) = */ FLAC__U64L(0x6a3fe5c60429),
	/* lg(8/7) = */ FLAC__U64L(0x315130157f7a),
	/* lg(16/15) = */ FLAC__U64L(0x17d60496cfbb),
	/* lg(32/31) = */ FLAC__U64L(0xbb9ca64ecac),
	/* lg(64/63) = */ FLAC__U64L(0x5d0fba187cd),
	/* lg(128/127) = */ FLAC__U64L(0x2e58f7441ee),
	/* lg(256/255) = */ FLAC__U64L(0x1720d9c06a8),
	/* lg(512/511) = */ FLAC__U64L(0xb8d8752173),
	/* lg(1024/1023) = */ FLAC__U64L(0x5c60aa252e),
	/* lg(2048/2047) = */ FLAC__U64L(0x2e2d71b0d8),
	/* lg(4096/4095) = */ FLAC__U64L(0x1716001719),
	/* lg(8192/8191) = */ FLAC__U64L(0xb8ad1de1b),
	/* lg(16384/16383) = */ FLAC__U64L(0x5c55d640d),
	/* lg(32768/32767) = */ FLAC__U64L(0x2e2abcf52)
	}
	};
	#endif

	FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, unsigned fracbits, unsigned precision)
	{
	const FLAC__uint32 ONE = (1u << fracbits);
	const FLAC__uint32 *table = log2_lookup[fracbits >> 2];

	FLAC__ASSERT(fracbits < 32);
	FLAC__ASSERT((fracbits & 0x3) == 0);

	if(x < ONE)
	return 0;

	if(precision > LOG2_LOOKUP_PRECISION)
	precision = LOG2_LOOKUP_PRECISION;

	/* Knuth's algorithm for computing logarithms, optimized for base-2 with lookup tables */
	{
	FLAC__uint32 y = 0;
	FLAC__uint32 z = x >> 1, k = 1;
	while (x > ONE && k < precision) {
	if (x - z >= ONE) {
	x -= z;
	z = x >> k;
	y += table[k];
	}
	else {
	z >>= 1;
	k++;
	}
	}
	return y;
	}
	}

	#endif /* defined FLAC__INTEGER_ONLY_LIBRARY */