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1 /* libFLAC - Free Lossless Audio Codec library
2  * Copyright (C) 2004-2009  Josh Coalson
3  * Copyright (C) 2011-2016  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  * All the code in libFLAC that uses float and double
44  * should be protected by checks of the macro
45  * FLAC__INTEGER_ONLY_LIBRARY.
46  *
47  */
48 #ifndef FLAC__INTEGER_ONLY_LIBRARY
49 /*
50  * FLAC__real is the basic floating point type used in LPC analysis.
51  *
52  * WATCHOUT: changing FLAC__real will change the signatures of many
53  * functions that have assembly language equivalents and break them.
54  */
55 typedef float FLAC__real;
56 #else
57 /*
58  * The convention for FLAC__fixedpoint is to use the upper 16 bits
59  * for the integer part and lower 16 bits for the fractional part.
60  */
61 typedef FLAC__int32 FLAC__fixedpoint;
62 extern const FLAC__fixedpoint FLAC__FP_ZERO;
63 extern const FLAC__fixedpoint FLAC__FP_ONE_HALF;
64 extern const FLAC__fixedpoint FLAC__FP_ONE;
65 extern const FLAC__fixedpoint FLAC__FP_LN2;
66 extern const FLAC__fixedpoint FLAC__FP_E;
67 
68 #define FLAC__fixedpoint_trunc(x) ((x)>>16)
69 
70 #define FLAC__fixedpoint_mul(x, y) ( (FLAC__fixedpoint) ( ((FLAC__int64)(x)*(FLAC__int64)(y)) >> 16 ) )
71 
72 #define FLAC__fixedpoint_div(x, y) ( (FLAC__fixedpoint) ( ( ((FLAC__int64)(x)<<32) / (FLAC__int64)(y) ) >> 16 ) )
73 
74 /*
75  *	FLAC__fixedpoint_log2()
76  *	--------------------------------------------------------------------
77  *	Returns the base-2 logarithm of the fixed-point number 'x' using an
78  *	algorithm by Knuth for x >= 1.0
79  *
80  *	'fracbits' is the number of fractional bits of 'x'.  'fracbits' must
81  *	be < 32 and evenly divisible by 4 (0 is OK but not very precise).
82  *
83  *	'precision' roughly limits the number of iterations that are done;
84  *	use (unsigned)(-1) for maximum precision.
85  *
86  *	If 'x' is less than one -- that is, x < (1<<fracbits) -- then this
87  *	function will punt and return 0.
88  *
89  *	The return value will also have 'fracbits' fractional bits.
90  */
91 FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, unsigned fracbits, unsigned precision);
92 
93 #endif
94 
95 #endif
96