PeerStreamer

/*

 * portable IEEE float/double read/write functions

 *

 * Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file intfloat_readwrite.c

 * Portable IEEE float/double read/write functions.

 */

#include "common.h"

#include "intfloat_readwrite.h"

double av_int2dbl(int64_t v){

    if(v+v > 0xFFELLU<<52)

        return 0.0/0.0;

    return ldexp(((v&((1LL<<52)-1)) + (1LL<<52)) * (v>>63|1), (v>>52&0x7FF)-1075);

}

float av_int2flt(int32_t v){

    if(v+v > 0xFF000000U)

        return 0.0/0.0;

    return ldexp(((v&0x7FFFFF) + (1<<23)) * (v>>31|1), (v>>23&0xFF)-150);

}

double av_ext2dbl(const AVExtFloat ext){

    uint64_t m = 0;

    int e, i;

    for (i = 0; i < 8; i++)

        m |= (uint64_t)ext.mantissa[i]<<(56-(i<<3));

    e = (((int)ext.exponent[0]&0x7f)<<8) | ext.exponent[1];

    if (e == 0x7fff && m)

        return 0.0/0.0;

    e -= 16383 + 63;        /* In IEEE 80 bits, the whole (i.e. 1.xxxx)

                             * mantissa bit is written as opposed to the

                             * single and double precision formats */

    if (ext.exponent[0]&0x80)

        return ldexp(-m, e);

    return ldexp(m, e);

}

int64_t av_dbl2int(double d){

    int e;

    if     ( !d) return 0;

    else if(d-d) return 0x7FF0000000000000LL + ((int64_t)(d<0)<<63) + (d!=d);

    d= frexp(d, &e);

    return (int64_t)(d<0)<<63 | (e+1022LL)<<52 | (int64_t)((fabs(d)-0.5)*(1LL<<53));

}

int32_t av_flt2int(float d){

    int e;

    if     ( !d) return 0;

    else if(d-d) return 0x7F800000 + ((d<0)<<31) + (d!=d);

    d= frexp(d, &e);

    return (d<0)<<31 | (e+126)<<23 | (int64_t)((fabs(d)-0.5)*(1<<24));

}

AVExtFloat av_dbl2ext(double d){

    struct AVExtFloat ext;

    int e, i; double f; uint64_t m;

    f = fabs(frexp(d, &e));

    if (f >= 0.5 && f < 1) {

        e += 16382;

        ext.exponent[0] = e>>8;

        ext.exponent[1] = e;

        m = (uint64_t)ldexp(f, 64);

        for (i=0; i < 8; i++)

            ext.mantissa[i] = m>>(56-(i<<3));

    } else if (f == 0.0) {

        memset (&ext, 0, 10);

    } else {

        ext.exponent[0] = 0x7f; ext.exponent[1] = 0xff;

        memset (&ext.mantissa, 0, 8);

        if (f != 1/0.0)

            ext.mantissa[0] = ~0;

    }

    if (d < 0)

        ext.exponent[0] |= 0x80;

    return ext;

}