void qore_number_private::applyRoundingHeuristic(QoreString& str, qore_size_t dp, qore_size_t last) {
// if there are some significant digits after the decimal point (signal)
bool signal = false;
// the position of the last significant digit
qore_offset_t pos = (qore_offset_t)dp;
qore_size_t i = dp;
// the last digit found in the sequence
char lc = 0;
// 0 or 9 count
unsigned cnt = 0;
bool has_e = (str[last] == 'e');
// don't check the last character
--last;
// check all except the last digit
while (i < last) {
char c = str[i++];
if (c == '0' || c == '9') {
// continue the sequence
if (c == lc) {
++cnt;
continue;
}
// check for 2nd threshold
if ((i == last) && cnt > QORE_MPFR_ROUND_THRESHOLD_2) {
break;
}
// set last digit to digit found
lc = c;
// if first digit, then do not set signal flag
if (i == (dp + 1))
continue;
}
else {
// check for 2nd threshold
if ((i == last) && cnt > QORE_MPFR_ROUND_THRESHOLD_2) {
break;
}
// no 0 or 9 digit found
lc = 0;
}
// mark position of the last significant digit
pos = i - 2;
//printd(5, "qore_number_private::applyRoundingHeuristic('%s') set pos: %lld ('%c') dp: %lld\n", str.getBuffer(), pos, str[pos], dp);
// found a non-noise digit
if (!signal)
signal = true;
// reset count
cnt = 0;
}
// round the number for display
if (signal && cnt > QORE_MPFR_ROUND_THRESHOLD) {
//printd(5, "ROUND BEFORE: (pos: %d dp: %d cnt: %d has_e: %d e: %c) %s\n", pos, dp, cnt, has_e, has_e ? str[pos + cnt + 4] : 'x', str.getBuffer());
// if rounding right after the decimal point, then remove the decimal point
if (pos == (qore_offset_t)dp)
--pos;
if (has_e && str[pos + cnt + 3] == 'e')
--cnt;
// remove the excess digits
if (!has_e)
str.terminate(pos + 1);
else
str.replace(pos + 1, cnt + 3, (const char*)0);
// rounding down is easy; the truncation is enough
if (lc == '9') // round up
roundUp(str, pos);
//printd(5, "ROUND AFTER: %s\n", str.getBuffer());
}
}
int qore_number_private::formatNumberString(QoreString& num, const QoreString& fmt, ExceptionSink* xsink) {
assert(!num.empty());
assert(num.getEncoding() == fmt.getEncoding());
// get the length of the format string in characters (not bytes)
qore_size_t fl = fmt.length();
if (fmt.empty() || fl == 2) {
printd(5, "qore_number_private::formatNumberString() invalid format string: '%s' for number: '%s'\n", fmt.getBuffer(), num.getBuffer());
return 0;
}
// get thousands separator character
QoreString tsep;
if (tsep.concat(fmt, 0, 1, xsink))
return -1;
// decimal separator
QoreString dsep;
// number of digits after the decimal separator
unsigned prec = 0;
if (fl > 1) {
if (dsep.concat(fmt, 1, 1, xsink))
return -1;
// get byte offset of start of decimal precision number
qore_offset_t i = fmt.getByteOffset(2, xsink);
if (*xsink)
return -1;
assert(i >= 2);
prec = atoi(fmt.getBuffer() + i);
if (!prec)
dsep.clear();
}
//printd(5, "qore_number_private::formatNumberString() tsep: '%s' dsep: '%s' prec: %d '%s'\n", tsep.getBuffer(), dsep.getBuffer(), prec, num.getBuffer());
// find decimal point
qore_offset_t dp = num.find('.');
if (dp != -1) {
// how many digits do we have now after the decimal point
qore_size_t d = num.strlen() - dp - 1;
assert(d);
if (d < prec)
num.addch('0', prec - d);
else if (d > prec) {
if ((num[dp + prec + 1] > '4') && (roundUp(num, dp + prec)))
++dp;
num.terminate(dp + prec + 1);
}
// now substitute decimal point if necessary
if (dsep.strlen() != 1 || dsep[0] != '.')
num.replace(dp, 1, dsep.getBuffer());
}
else {
dp = num.size();
if (prec) {
// add decimal point
num.concat(&dsep, xsink);
assert(!*xsink);
// add zeros for significant digits
num.addch('0', prec);
}
}
// now insert thousands separator
// start of digits before the decimal point
qore_offset_t ds = num[0] == '-' ? 1 : 0;
// work backwards from the decimal point
qore_offset_t i = dp - 3;
while (i > ds) {
num.replace(i, 0, tsep.getBuffer());
i -= 3;
}
//printd(0, "qore_number_private::formatNumberString() ok '%s'\n", num.getBuffer());
//assert(false); xxx
return 0;
}