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
