1 /* libFLAC - Free Lossless Audio Codec library
2 * Copyright (C) 2004-2009 Josh Coalson
3 * Copyright (C) 2011-2016 Xiph.Org Foundation
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
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.
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.
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.
33 #ifndef FLAC__PRIVATE__FLOAT_H
34 #define FLAC__PRIVATE__FLOAT_H
40 #include "FLAC/ordinals.h"
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.
48 #ifndef FLAC__INTEGER_ONLY_LIBRARY
50 * FLAC__real is the basic floating point type used in LPC analysis.
52 * WATCHOUT: changing FLAC__real will change the signatures of many
53 * functions that have assembly language equivalents and break them.
55 typedef float FLAC__real;
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.
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;
68 #define FLAC__fixedpoint_trunc(x) ((x)>>16)
70 #define FLAC__fixedpoint_mul(x, y) ( (FLAC__fixedpoint) ( ((FLAC__int64)(x)*(FLAC__int64)(y)) >> 16 ) )
72 #define FLAC__fixedpoint_div(x, y) ( (FLAC__fixedpoint) ( ( ((FLAC__int64)(x)<<32) / (FLAC__int64)(y) ) >> 16 ) )
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
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).
83 * 'precision' roughly limits the number of iterations that are done;
84 * use (unsigned)(-1) for maximum precision.
86 * If 'x' is less than one -- that is, x < (1<<fracbits) -- then this
87 * function will punt and return 0.
89 * The return value will also have 'fracbits' fractional bits.
91 FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, unsigned fracbits, unsigned precision);