Function FormatPositional

numpy/core/src/multiarray/dragon4.c:1639–1866

* Outputs the positive number with positional notation: ddddd.dddd * The output is always NUL terminated and the output length (not including the * NUL) is returned. * * Arguments: * buffer - buffer to output into * bufferSize - maximum characters that can be printed to buffer * mantissa - value significand * exponent - value exponent in base 2 * signbit - value of the sign

 * See Dragon4_Options for description of remaining arguments.
 */
static npy_uint32
FormatPositional(char *buffer, npy_uint32 bufferSize, BigInt *mantissa,
                 npy_int32 exponent, char signbit, npy_uint32 mantissaBit,
                 npy_bool hasUnequalMargins, DigitMode digit_mode,
                 CutoffMode cutoff_mode, npy_int32 precision,
                 npy_int32 min_digits, TrimMode trim_mode,
                 npy_int32 digits_left, npy_int32 digits_right)
{
    npy_int32 printExponent;
    npy_int32 numDigits, numWholeDigits=0, has_sign=0;
    npy_int32 add_digits;

    npy_int32 maxPrintLen = (npy_int32)bufferSize - 1, pos = 0;

    /* track the # of digits past the decimal point that have been printed */
    npy_int32 numFractionDigits = 0, desiredFractionalDigits;

    DEBUG_ASSERT(bufferSize > 0);

    if (digit_mode != DigitMode_Unique) {
        DEBUG_ASSERT(precision >= 0);
    }

    if (signbit == '+' && pos < maxPrintLen) {
        buffer[pos++] = '+';
        has_sign = 1;
    }
    else if (signbit == '-' && pos < maxPrintLen) {
        buffer[pos++] = '-';
        has_sign = 1;
    }

    numDigits = Dragon4(mantissa, exponent, mantissaBit, hasUnequalMargins,
                        digit_mode, cutoff_mode, precision, min_digits,
                        buffer + has_sign, maxPrintLen - has_sign,
                        &printExponent);

    DEBUG_ASSERT(numDigits > 0);
    DEBUG_ASSERT(numDigits <= bufferSize);

    /* if output has a whole number */
    if (printExponent >= 0) {
        /* leave the whole number at the start of the buffer */
        numWholeDigits = printExponent+1;
        if (numDigits <= numWholeDigits) {
            npy_int32 count = numWholeDigits - numDigits;
            pos += numDigits;

            /* don't overflow the buffer */
            if (pos + count > maxPrintLen) {
                count = maxPrintLen - pos;
            }

            /* add trailing zeros up to the decimal point */
            numDigits += count;
            for ( ; count > 0; count--) {
                buffer[pos++] = '0';
            }