Function OutputDouble

glslang/MachineIndependent/intermOut.cpp:1114–1162

Print infinities and NaNs, and numbers in a portable way. Goals: - portable (across IEEE 754 platforms) - shows all possible IEEE values - shows simple numbers in a simple way, e.g., no leading/trailing 0s - shows all digits, no premature rounding

//   - shows simple numbers in a simple way, e.g., no leading/trailing 0s
//   - shows all digits, no premature rounding
static void OutputDouble(TInfoSink& out, double value, TOutputTraverser::EExtraOutput extra)
{
    if (std::isinf(value)) {
        if (value < 0)
            out.debug << "-1.#INF";
        else
            out.debug << "+1.#INF";
    } else if (std::isnan(value))
        out.debug << "1.#IND";
    else {
        const int maxSize = 340;
        char buf[maxSize];
        const char* format = "%f";
        if (fabs(value) > 0.0 && (fabs(value) < 1e-5 || fabs(value) > 1e12))
            format = "%-.13e";
        int len = snprintf(buf, maxSize, format, value);
        assert(len < maxSize);

        // remove a leading zero in the 100s slot in exponent; it is not portable
        // pattern:   XX...XXXe+0XX or XX...XXXe-0XX
        if (len > 5) {
            if (buf[len-5] == 'e' && (buf[len-4] == '+' || buf[len-4] == '-') && buf[len-3] == '0') {
                buf[len-3] = buf[len-2];
                buf[len-2] = buf[len-1];
                buf[len-1] = '\0';
            }
        }

        out.debug << buf;

        switch (extra) {
        case TOutputTraverser::BinaryDoubleOutput:
        {
            uint64_t b;
            static_assert(sizeof(b) == sizeof(value), "sizeof(uint64_t) != sizeof(double)");
            memcpy(&b, &value, sizeof(b));

            out.debug << " : ";
            for (size_t i = 0; i < 8 * sizeof(value); ++i, ++b) {
                out.debug << ((b & 0x8000000000000000) != 0 ? "1" : "0");
                b <<= 1;
            }
            break;
        }
        default:
            break;
        }
    }
}

static void OutputConstantUnion(TInfoSink& out, const TIntermTyped* node, const TConstUnionArray& constUnion,
    TOutputTraverser::EExtraOutput extra, int depth)