Function FormatScientific

numpy/core/src/multiarray/dragon4.c:1884–2069

* Outputs the positive number with scientific notation: d.dddde[sign]ddd * 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 th

 * See Dragon4_Options for description of remaining arguments.
 */
static npy_uint32
FormatScientific (char *buffer, npy_uint32 bufferSize, BigInt *mantissa,
                  npy_int32 exponent, char signbit, npy_uint32 mantissaBit,
                  npy_bool hasUnequalMargins, DigitMode digit_mode,
                  npy_int32 precision, npy_int32 min_digits, TrimMode trim_mode,
                  npy_int32 digits_left, npy_int32 exp_digits)
{
    npy_int32 printExponent;
    npy_int32 numDigits;
    char *pCurOut;
    npy_int32 numFractionDigits;
    npy_int32 leftchars;
    npy_int32 add_digits;

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

    DEBUG_ASSERT(bufferSize > 0);

    pCurOut = buffer;

    /* add any whitespace padding to left side */
    leftchars = 1 + (signbit == '-' || signbit == '+');
    if (digits_left > leftchars) {
        int i;
        for (i = 0; i < digits_left - leftchars && bufferSize > 1; i++) {
            *pCurOut = ' ';
            pCurOut++;
            --bufferSize;
        }
    }

    if (signbit == '+' && bufferSize > 1) {
        *pCurOut = '+';
        pCurOut++;
        --bufferSize;
    }
    else if (signbit == '-'  && bufferSize > 1) {
        *pCurOut = '-';
        pCurOut++;
        --bufferSize;
    }

    numDigits = Dragon4(mantissa, exponent, mantissaBit, hasUnequalMargins,
                        digit_mode, CutoffMode_TotalLength,
                        precision < 0 ? -1 : precision + 1,
                        min_digits < 0 ? -1 : min_digits + 1,
                        pCurOut, bufferSize, &printExponent);

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

    /* keep the whole number as the first digit */
    if (bufferSize > 1) {
        pCurOut += 1;
        bufferSize -= 1;
    }