Function pb_encode_float_as_double

lib/nanopb/pb_encode.c:954–999

#ifdef PB_CONVERT_DOUBLE_FLOAT
bool pb_encode_float_as_double(pb_ostream_t *stream, float value)
{
    union { float f; uint32_t i; } in;
    uint_least8_t sign;
    int exponent;
    uint64_t mantissa;

    in.f = value;

    /* Decompose input value */
    sign = (uint_least8_t)((in.i >> 31) & 1);
    exponent = (int)((in.i >> 23) & 0xFF) - 127;
    mantissa = in.i & 0x7FFFFF;

    if (exponent == 128)
    {
        /* Special value (NaN etc.) */
        exponent = 1024;
    }
    else if (exponent == -127)
    {
        if (!mantissa)
        {
            /* Zero */
            exponent = -1023;
        }
        else
        {
            /* Denormalized */
            mantissa <<= 1;
            while (!(mantissa & 0x800000))
            {
                mantissa <<= 1;
                exponent--;
            }
            mantissa &= 0x7FFFFF;
        }
    }

    /* Combine fields */
    mantissa <<= 29;
    mantissa |= (uint64_t)(exponent + 1023) << 52;
    mantissa |= (uint64_t)sign << 63;

    return pb_encode_fixed64(stream, &mantissa);
}
#endif