float.h (3801B)
1 /* libFLAC - Free Lossless Audio Codec library 2 * Copyright (C) 2004,2005 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