• float.h
  • /* libFLAC - Free Lossless Audio Codec library
     * Copyright (C) 2004-2009  Josh Coalson
     * Copyright (C) 2011-2025  Xiph.Org Foundation
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     *
     * - Redistributions of source code must retain the above copyright
     * notice, this list of conditions and the following disclaimer.
     *
     * - Redistributions in binary form must reproduce the above copyright
     * notice, this list of conditions and the following disclaimer in the
     * documentation and/or other materials provided with the distribution.
     *
     * - Neither the name of the Xiph.org Foundation nor the names of its
     * contributors may be used to endorse or promote products derived from
     * this software without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
     * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     */
    
    #ifndef FLAC__PRIVATE__FLOAT_H
    #define FLAC__PRIVATE__FLOAT_H
    
    #ifdef HAVE_CONFIG_H
    #include <config.h>
    #endif
    
    #include "FLAC/ordinals.h"
    
    /*
     * All the code in libFLAC that uses float and double
     * should be protected by checks of the macro
     * FLAC__INTEGER_ONLY_LIBRARY.
     *
     */
    #ifndef FLAC__INTEGER_ONLY_LIBRARY
    /*
     * FLAC__real is the basic floating point type used in LPC analysis.
     *
     * WATCHOUT: changing FLAC__real will change the signatures of many
     * functions that have assembly language equivalents and break them.
     */
    typedef float FLAC__real;
    #else
    /*
     * The convention for FLAC__fixedpoint is to use the upper 16 bits
     * for the integer part and lower 16 bits for the fractional part.
     */
    typedef FLAC__int32 FLAC__fixedpoint;
    extern const FLAC__fixedpoint FLAC__FP_ZERO;
    extern const FLAC__fixedpoint FLAC__FP_ONE_HALF;
    extern const FLAC__fixedpoint FLAC__FP_ONE;
    extern const FLAC__fixedpoint FLAC__FP_LN2;
    extern const FLAC__fixedpoint FLAC__FP_E;
    
    #define FLAC__fixedpoint_trunc(x) ((x)>>16)
    
    #define FLAC__fixedpoint_mul(x, y) ( (FLAC__fixedpoint) ( ((FLAC__int64)(x)*(FLAC__int64)(y)) >> 16 ) )
    
    #define FLAC__fixedpoint_div(x, y) ( (FLAC__fixedpoint) ( ( ((FLAC__int64)(x)<<32) / (FLAC__int64)(y) ) >> 16 ) )
    
    /*
     *	FLAC__fixedpoint_log2()
     *	--------------------------------------------------------------------
     *	Returns the base-2 logarithm of the fixed-point number 'x' using an
     *	algorithm by Knuth for x >= 1.0
     *
     *	'fracbits' is the number of fractional bits of 'x'.  'fracbits' must
     *	be < 32 and evenly divisible by 4 (0 is OK but not very precise).
     *
     *	'precision' roughly limits the number of iterations that are done;
     *	use (uint32_t)(-1) for maximum precision.
     *
     *	If 'x' is less than one -- that is, x < (1<<fracbits) -- then this
     *	function will punt and return 0.
     *
     *	The return value will also have 'fracbits' fractional bits.
     */
    FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, uint32_t fracbits, uint32_t precision);
    
    #endif
    
    #endif