yading@11: /*
yading@11:  * portable IEEE float/double read/write functions
yading@11:  *
yading@11:  * Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: /**
yading@11:  * @file
yading@11:  * portable IEEE float/double read/write functions
yading@11:  */
yading@11: 
yading@11: #include <stdint.h>
yading@11: #include "common.h"
yading@11: #include "mathematics.h"
yading@11: #include "intfloat_readwrite.h"
yading@11: 
yading@11: double av_int2dbl(int64_t v){
yading@11:     if((uint64_t)v+v > 0xFFEULL<<52)
yading@11:         return NAN;
yading@11:     return ldexp(((v&((1LL<<52)-1)) + (1LL<<52)) * (v>>63|1), (v>>52&0x7FF)-1075);
yading@11: }
yading@11: 
yading@11: float av_int2flt(int32_t v){
yading@11:     if((uint32_t)v+v > 0xFF000000U)
yading@11:         return NAN;
yading@11:     return ldexp(((v&0x7FFFFF) + (1<<23)) * (v>>31|1), (v>>23&0xFF)-150);
yading@11: }
yading@11: 
yading@11: double av_ext2dbl(const AVExtFloat ext){
yading@11:     uint64_t m = 0;
yading@11:     int e, i;
yading@11: 
yading@11:     for (i = 0; i < 8; i++)
yading@11:         m = (m<<8) + ext.mantissa[i];
yading@11:     e = (((int)ext.exponent[0]&0x7f)<<8) | ext.exponent[1];
yading@11:     if (e == 0x7fff && m)
yading@11:         return NAN;
yading@11:     e -= 16383 + 63;        /* In IEEE 80 bits, the whole (i.e. 1.xxxx)
yading@11:                              * mantissa bit is written as opposed to the
yading@11:                              * single and double precision formats. */
yading@11:     if (ext.exponent[0]&0x80)
yading@11:         m= -m;
yading@11:     return ldexp(m, e);
yading@11: }
yading@11: 
yading@11: int64_t av_dbl2int(double d){
yading@11:     int e;
yading@11:     if     ( !d) return 0;
yading@11:     else if(d-d) return 0x7FF0000000000000LL + ((int64_t)(d<0)<<63) + (d!=d);
yading@11:     d= frexp(d, &e);
yading@11:     return (int64_t)(d<0)<<63 | (e+1022LL)<<52 | (int64_t)((fabs(d)-0.5)*(1LL<<53));
yading@11: }
yading@11: 
yading@11: int32_t av_flt2int(float d){
yading@11:     int e;
yading@11:     if     ( !d) return 0;
yading@11:     else if(d-d) return 0x7F800000 + ((d<0)<<31) + (d!=d);
yading@11:     d= frexp(d, &e);
yading@11:     return (d<0)<<31 | (e+126)<<23 | (int64_t)((fabs(d)-0.5)*(1<<24));
yading@11: }
yading@11: 
yading@11: AVExtFloat av_dbl2ext(double d){
yading@11:     struct AVExtFloat ext= {{0}};
yading@11:     int e, i; double f; uint64_t m;
yading@11: 
yading@11:     f = fabs(frexp(d, &e));
yading@11:     if (f >= 0.5 && f < 1) {
yading@11:         e += 16382;
yading@11:         ext.exponent[0] = e>>8;
yading@11:         ext.exponent[1] = e;
yading@11:         m = (uint64_t)ldexp(f, 64);
yading@11:         for (i=0; i < 8; i++)
yading@11:             ext.mantissa[i] = m>>(56-(i<<3));
yading@11:     } else if (f != 0.0) {
yading@11:         ext.exponent[0] = 0x7f; ext.exponent[1] = 0xff;
yading@11:         if (!isinf(f))
yading@11:             ext.mantissa[0] = ~0;
yading@11:     }
yading@11:     if (d < 0)
yading@11:         ext.exponent[0] |= 0x80;
yading@11:     return ext;
yading@11: }