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1 /* libFLAC - Free Lossless Audio Codec library
2  * Copyright (C) 2004-2009  Josh Coalson
3  * Copyright (C) 2011-2014  Xiph.Org Foundation
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  * - Redistributions of source code must retain the above copyright
10  * notice, this list of conditions and the following disclaimer.
11  *
12  * - Redistributions in binary form must reproduce the above copyright
13  * notice, this list of conditions and the following disclaimer in the
14  * documentation and/or other materials provided with the distribution.
15  *
16  * - Neither the name of the Xiph.org Foundation nor the names of its
17  * contributors may be used to endorse or promote products derived from
18  * this software without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
24  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
26  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
27  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
28  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
29  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
30  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 #ifndef FLAC__PRIVATE__FLOAT_H
34 #define FLAC__PRIVATE__FLOAT_H
35 
36 #ifdef HAVE_CONFIG_H
37 #include <config.h>
38 #endif
39 
40 #include "FLAC/ordinals.h"
41 
42 /*
43  * These typedefs make it easier to ensure that integer versions of
44  * the library really only contain integer operations.  All the code
45  * in libFLAC should use FLAC__float and FLAC__double in place of
46  * float and double, and be protected by checks of the macro
47  * FLAC__INTEGER_ONLY_LIBRARY.
48  *
49  * FLAC__real is the basic floating point type used in LPC analysis.
50  */
51 #ifndef FLAC__INTEGER_ONLY_LIBRARY
52 typedef double FLAC__double;
53 typedef float FLAC__float;
54 /*
55  * WATCHOUT: changing FLAC__real will change the signatures of many
56  * functions that have assembly language equivalents and break them.
57  */
58 typedef float FLAC__real;
59 #else
60 /*
61  * The convention for FLAC__fixedpoint is to use the upper 16 bits
62  * for the integer part and lower 16 bits for the fractional part.
63  */
64 typedef FLAC__int32 FLAC__fixedpoint;
65 extern const FLAC__fixedpoint FLAC__FP_ZERO;
66 extern const FLAC__fixedpoint FLAC__FP_ONE_HALF;
67 extern const FLAC__fixedpoint FLAC__FP_ONE;
68 extern const FLAC__fixedpoint FLAC__FP_LN2;
69 extern const FLAC__fixedpoint FLAC__FP_E;
70 
71 #define FLAC__fixedpoint_trunc(x) ((x)>>16)
72 
73 #define FLAC__fixedpoint_mul(x, y) ( (FLAC__fixedpoint) ( ((FLAC__int64)(x)*(FLAC__int64)(y)) >> 16 ) )
74 
75 #define FLAC__fixedpoint_div(x, y) ( (FLAC__fixedpoint) ( ( ((FLAC__int64)(x)<<32) / (FLAC__int64)(y) ) >> 16 ) )
76 
77 /*
78  *	FLAC__fixedpoint_log2()
79  *	--------------------------------------------------------------------
80  *	Returns the base-2 logarithm of the fixed-point number 'x' using an
81  *	algorithm by Knuth for x >= 1.0
82  *
83  *	'fracbits' is the number of fractional bits of 'x'.  'fracbits' must
84  *	be < 32 and evenly divisible by 4 (0 is OK but not very precise).
85  *
86  *	'precision' roughly limits the number of iterations that are done;
87  *	use (unsigned)(-1) for maximum precision.
88  *
89  *	If 'x' is less than one -- that is, x < (1<<fracbits) -- then this
90  *	function will punt and return 0.
91  *
92  *	The return value will also have 'fracbits' fractional bits.
93  */
94 FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, unsigned fracbits, unsigned precision);
95 
96 #endif
97 
98 #endif
99