intfloat_readwrite.c File Reference

#include "common.h"
#include "intfloat_readwrite.h"

Go to the source code of this file.

Functions
double	av_int2dbl (int64_t v)
float	av_int2flt (int32_t v)
double	av_ext2dbl (const AVExtFloat ext)
int64_t	av_dbl2int (double d)
int32_t	av_flt2int (float d)
AVExtFloat	av_dbl2ext (double d)

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Detailed Description

Portable IEEE float/double read/write functions.

Definition in file intfloat_readwrite.c.

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Function Documentation

AVExtFloat av_dbl2ext

(

double

d

)

Definition at line 76 of file intfloat_readwrite.c.

References AVExtFloat::exponent, and AVExtFloat::mantissa.

                               {
    struct AVExtFloat ext= {{0}};
    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) {
        ext.exponent[0] = 0x7f; ext.exponent[1] = 0xff;
        if (f != 1/0.0)
            ext.mantissa[0] = ~0;
    }
    if (d < 0)
        ext.exponent[0] |= 0x80;
    return ext;
}

int64_t av_dbl2int

(

double

d

)

Definition at line 60 of file intfloat_readwrite.c.

Referenced by ffm_write_header(), gxf_write_umf_media_audio(), put_amf_double(), and put_ebml_float().

                            {
    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));
}

double av_ext2dbl

(

const AVExtFloat

ext

)

Definition at line 43 of file intfloat_readwrite.c.

References AVExtFloat::exponent, and AVExtFloat::mantissa.

Referenced by get_aiff_header().

                                       {
    uint64_t m = 0;
    int e, i;

    for (i = 0; i < 8; i++)
        m = (m<<8) + ext.mantissa[i];
    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)
        m= -m;
    return ldexp(m, e);
}

int32_t av_flt2int

(

float

d

)

Definition at line 68 of file intfloat_readwrite.c.

                           {
    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));
}

double av_int2dbl

(

int64_t

v

)

Definition at line 31 of file intfloat_readwrite.c.

Referenced by amf_parse_object(), ebml_read_float(), ffm_read_header(), mov_read_stsd(), and nuv_header().

                            {
    if(v+v > 0xFFEULL<<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

)

Definition at line 37 of file intfloat_readwrite.c.

Referenced by ebml_read_float(), fourxm_read_header(), and thp_read_header().

                           {
    if(v+v > 0xFF000000U)
        return 0.0/0.0;
    return ldexp(((v&0x7FFFFF) + (1<<23)) * (v>>31|1), (v>>23&0xFF)-150);
}

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