float.h

00001 /* libFLAC - Free Lossless Audio Codec library
00002  * Copyright (C) 2004-2009  Josh Coalson
00003  * Copyright (C) 2011-2014  Xiph.Org Foundation
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions
00007  * are met:
00008  *
00009  * - Redistributions of source code must retain the above copyright
00010  * notice, this list of conditions and the following disclaimer.
00011  *
00012  * - Redistributions in binary form must reproduce the above copyright
00013  * notice, this list of conditions and the following disclaimer in the
00014  * documentation and/or other materials provided with the distribution.
00015  *
00016  * - Neither the name of the Xiph.org Foundation nor the names of its
00017  * contributors may be used to endorse or promote products derived from
00018  * this software without specific prior written permission.
00019  *
00020  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00021  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00022  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
00023  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
00024  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00025  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
00026  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
00027  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
00028  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00029  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00030  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00031  */
00032 
00033 #ifndef FLAC__PRIVATE__FLOAT_H
00034 #define FLAC__PRIVATE__FLOAT_H
00035 
00036 #ifdef HAVE_CONFIG_H
00037 #include <config.h>
00038 #endif
00039 
00040 #include "FLAC/ordinals.h"
00041 
00042 /*
00043  * These typedefs make it easier to ensure that integer versions of
00044  * the library really only contain integer operations.  All the code
00045  * in libFLAC should use FLAC__float and FLAC__double in place of
00046  * float and double, and be protected by checks of the macro
00047  * FLAC__INTEGER_ONLY_LIBRARY.
00048  *
00049  * FLAC__real is the basic floating point type used in LPC analysis.
00050  */
00051 #ifndef FLAC__INTEGER_ONLY_LIBRARY
00052 typedef double FLAC__double;
00053 typedef float FLAC__float;
00054 /*
00055  * WATCHOUT: changing FLAC__real will change the signatures of many
00056  * functions that have assembly language equivalents and break them.
00057  */
00058 typedef float FLAC__real;
00059 #else
00060 /*
00061  * The convention for FLAC__fixedpoint is to use the upper 16 bits
00062  * for the integer part and lower 16 bits for the fractional part.
00063  */
00064 typedef FLAC__int32 FLAC__fixedpoint;
00065 extern const FLAC__fixedpoint FLAC__FP_ZERO;
00066 extern const FLAC__fixedpoint FLAC__FP_ONE_HALF;
00067 extern const FLAC__fixedpoint FLAC__FP_ONE;
00068 extern const FLAC__fixedpoint FLAC__FP_LN2;
00069 extern const FLAC__fixedpoint FLAC__FP_E;
00070 
00071 #define FLAC__fixedpoint_trunc(x) ((x)>>16)
00072 
00073 #define FLAC__fixedpoint_mul(x, y) ( (FLAC__fixedpoint) ( ((FLAC__int64)(x)*(FLAC__int64)(y)) >> 16 ) )
00074 
00075 #define FLAC__fixedpoint_div(x, y) ( (FLAC__fixedpoint) ( ( ((FLAC__int64)(x)<<32) / (FLAC__int64)(y) ) >> 16 ) )
00076 
00077 /*
00078  *  FLAC__fixedpoint_log2()
00079  *  --------------------------------------------------------------------
00080  *  Returns the base-2 logarithm of the fixed-point number 'x' using an
00081  *  algorithm by Knuth for x >= 1.0
00082  *
00083  *  'fracbits' is the number of fractional bits of 'x'.  'fracbits' must
00084  *  be < 32 and evenly divisible by 4 (0 is OK but not very precise).
00085  *
00086  *  'precision' roughly limits the number of iterations that are done;
00087  *  use (unsigned)(-1) for maximum precision.
00088  *
00089  *  If 'x' is less than one -- that is, x < (1<<fracbits) -- then this
00090  *  function will punt and return 0.
00091  *
00092  *  The return value will also have 'fracbits' fractional bits.
00093  */
00094 FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, unsigned fracbits, unsigned precision);
00095 
00096 #endif
00097 
00098 #endif