Function cvt_decompose

src/common/cvt.cpp:2597–2819

static void hex_to_value(const char*& string, const char* end, RetPtr* retValue);

static SSHORT cvt_decompose(const char*	string,
							USHORT		length,
							RetPtr*		return_value,
							ErrorFunction err)
{
/**************************************
 *
 *      d e c o m p o s e
 *
 **************************************
 *
 * Functional description
 *      Decompose a numeric string in mantissa and exponent,
 *      or if it is in hexadecimal notation.
 *
 **************************************/

	dsc errd;
	MOVE_CLEAR(&errd, sizeof(errd));
	errd.dsc_dtype = dtype_text;
	errd.dsc_ttype() = ttype_ascii;
	errd.dsc_length = length;
	errd.dsc_address = reinterpret_cast<UCHAR*>(const_cast<char*>(string));

	SSHORT scale = 0;
	int sign = 0;
	bool digit_seen = false, fraction = false;

	const char* p = string;
	const char* end = p + length;

	// skip initial spaces
	while (p < end && *p == ' ')
		++p;

	// Check if this is a numeric hex string. Must start with 0x or 0X, and be
	// no longer than 16 hex digits + 2 (the length of the 0x prefix) = 18.
	if (p + 2 < end && p[0] == '0' && UPPER(p[1]) == 'X')
	{
		p += 2; // skip over 0x part

		// skip non spaces
		const char* q = p;
		while (q < end && *q && *q != ' ')
			++q;

		const char* digits_end = q;

		// skip trailing spaces
		while (q < end && *q == ' ')
			q++;

		if (q != end || end - p == 0 || (end - p) * 4 > return_value->maxSize() * 8)
		{
			CVT_conversion_error(&errd, err);
			return 0;
		}