Function exactNumericToStr

src/common/utils.cpp:1122–1196

void exactNumericToStr(SINT64 value, int scale, Firebird::string& target, bool append)
{
	if (value == 0)
	{
		if (append)
			target.append("0", 1);
		else
			target.assign("0", 1);
		return;
	}

	const int MAX_SCALE = 25;
	const int MAX_BUFFER = 50;

	if (scale < -MAX_SCALE || scale > MAX_SCALE)
	{
		fb_assert(false);
		return; // throw exception here?
	}

	const bool neg = value < 0;
	const bool dot = scale < 0; // Need the decimal separator or not?
	char buffer[MAX_BUFFER];
	int iter = MAX_BUFFER;

	buffer[--iter] = '\0';

	if (scale > 0)
	{
		while (scale-- > 0)
			buffer[--iter] = '0';
	}

	bool dot_used = false;
	FB_UINT64 uval = neg ? FB_UINT64(-(value + 1)) + 1 : value; // avoid problems with MIN_SINT64

	while (uval != 0)
	{
		buffer[--iter] = static_cast<char>(uval % 10) + '0';
		uval /= 10;

		if (dot && !++scale)
		{
			buffer[--iter] = '.';
			dot_used = true;
		}
	}

	if (dot)
	{
		// if scale > 0 we have N.M
		// if scale == 0 we have .M and we need 0.M
		// if scale < 0 we have pending zeroes and need 0.{0+}M
		if (!dot_used)
		{
			while (scale++ < 0)
				buffer[--iter] = '0';