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      1 /* libFLAC - Free Lossless Audio Codec library
      2  * Copyright (C) 2004,2005,2006,2007  Josh Coalson
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  *
      8  * - Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *
     11  * - Redistributions in binary form must reproduce the above copyright
     12  * notice, this list of conditions and the following disclaimer in the
     13  * documentation and/or other materials provided with the distribution.
     14  *
     15  * - Neither the name of the Xiph.org Foundation nor the names of its
     16  * contributors may be used to endorse or promote products derived from
     17  * this software without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     22  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
     23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     26  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     27  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     28  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     29  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef FLAC__PRIVATE__FLOAT_H
     33 #define FLAC__PRIVATE__FLOAT_H
     34 
     35 #ifdef HAVE_CONFIG_H
     36 #include <config.h>
     37 #endif
     38 
     39 #include "FLAC/ordinals.h"
     40 
     41 /*
     42  * These typedefs make it easier to ensure that integer versions of
     43  * the library really only contain integer operations.  All the code
     44  * in libFLAC should use FLAC__float and FLAC__double in place of
     45  * float and double, and be protected by checks of the macro
     46  * FLAC__INTEGER_ONLY_LIBRARY.
     47  *
     48  * FLAC__real is the basic floating point type used in LPC analysis.
     49  */
     50 #ifndef FLAC__INTEGER_ONLY_LIBRARY
     51 typedef double FLAC__double;
     52 typedef float FLAC__float;
     53 /*
     54  * WATCHOUT: changing FLAC__real will change the signatures of many
     55  * functions that have assembly language equivalents and break them.
     56  */
     57 typedef float FLAC__real;
     58 #else
     59 /*
     60  * The convention for FLAC__fixedpoint is to use the upper 16 bits
     61  * for the integer part and lower 16 bits for the fractional part.
     62  */
     63 typedef FLAC__int32 FLAC__fixedpoint;
     64 extern const FLAC__fixedpoint FLAC__FP_ZERO;
     65 extern const FLAC__fixedpoint FLAC__FP_ONE_HALF;
     66 extern const FLAC__fixedpoint FLAC__FP_ONE;
     67 extern const FLAC__fixedpoint FLAC__FP_LN2;
     68 extern const FLAC__fixedpoint FLAC__FP_E;
     69 
     70 #define FLAC__fixedpoint_trunc(x) ((x)>>16)
     71 
     72 #define FLAC__fixedpoint_mul(x, y) ( (FLAC__fixedpoint) ( ((FLAC__int64)(x)*(FLAC__int64)(y)) >> 16 ) )
     73 
     74 #define FLAC__fixedpoint_div(x, y) ( (FLAC__fixedpoint) ( ( ((FLAC__int64)(x)<<32) / (FLAC__int64)(y) ) >> 16 ) )
     75 
     76 /*
     77  *	FLAC__fixedpoint_log2()
     78  *	--------------------------------------------------------------------
     79  *	Returns the base-2 logarithm of the fixed-point number 'x' using an
     80  *	algorithm by Knuth for x >= 1.0
     81  *
     82  *	'fracbits' is the number of fractional bits of 'x'.  'fracbits' must
     83  *	be < 32 and evenly divisible by 4 (0 is OK but not very precise).
     84  *
     85  *	'precision' roughly limits the number of iterations that are done;
     86  *	use (unsigned)(-1) for maximum precision.
     87  *
     88  *	If 'x' is less than one -- that is, x < (1<<fracbits) -- then this
     89  *	function will punt and return 0.
     90  *
     91  *	The return value will also have 'fracbits' fractional bits.
     92  */
     93 FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, unsigned fracbits, unsigned precision);
     94 
     95 #endif
     96 
     97 #endif
     98