/**
* Format a number supplied as a decimal
*
* @param dval the decimal value
* @param fsb the FastStringBuffer to contain the result
*/
private void formatDecimal(BigDecimal dval, FastStringBuffer fsb) {
dval = dval.setScale(maxFractionPartSize, BigDecimal.ROUND_HALF_EVEN);
DecimalValue.decimalToString(dval, fsb);
int point = fsb.indexOf('.');
int intDigits;
if (point >= 0) {
int zz = maxFractionPartSize - minFractionPartSize;
while (zz > 0) {
if (fsb.charAt(fsb.length() - 1) == '0') {
fsb.setLength(fsb.length() - 1);
zz--;
} else {
break;
}
}
intDigits = point;
if (fsb.charAt(fsb.length() - 1) == '.') {
fsb.setLength(fsb.length() - 1);
}
} else {
intDigits = fsb.length();
if (minFractionPartSize > 0) {
fsb.append('.');
for (int i = 0; i < minFractionPartSize; i++) {
fsb.append('0');
}
}
}
if (minWholePartSize == 0 && intDigits == 1 && fsb.charAt(0) == '0') {
fsb.removeCharAt(0);
} else {
fsb.prependRepeated('0', minWholePartSize - intDigits);
}
}
/**
* Convert a double to a BigDecimal. In general there will be several BigDecimal values that are
* equal to the supplied value, and the one we want to choose is the one with fewest non-zero
* digits. The algorithm used is rather pragmatic: look for a string of zeroes or nines, try
* rounding the number down or up as approriate, then convert the adjusted value to a double to
* see if it's equal to the original: if not, use the original value unchanged.
*
* @param value the double to be converted
* @param precision 2 for a double, 1 for a float
* @return the result of conversion to a double
*/
public static BigDecimal adjustToDecimal(double value, int precision) {
final String zeros = (precision == 1 ? "00000" : "000000000");
final String nines = (precision == 1 ? "99999" : "999999999");
BigDecimal initial = new BigDecimal(value);
BigDecimal trial = null;
FastStringBuffer fsb = new FastStringBuffer(20);
DecimalValue.decimalToString(initial, fsb);
String s = fsb.toString();
int start = (s.charAt(0) == '-' ? 1 : 0);
int p = s.indexOf(".");
int i = s.lastIndexOf(zeros);
if (i > 0) {
if (p < 0 || i < p) {
// we're in the integer part
// try replacing all following digits with zeros and seeing if we get the same double back
FastStringBuffer sb = new FastStringBuffer(s.length());
sb.append(s.substring(0, i));
for (int n = i; n < s.length(); n++) {
sb.append(s.charAt(n) == '.' ? '.' : '0');
}
trial = new BigDecimal(sb.toString());
} else {
// we're in the fractional part
// try truncating the number before the zeros and seeing if we get the same double back
trial = new BigDecimal(s.substring(0, i));
}
} else {
i = s.indexOf(nines);
if (i >= 0) {
if (i == start) {
// number starts with 99999... or -99999. Try rounding up to 100000.. or -100000...
FastStringBuffer sb = new FastStringBuffer(s.length() + 1);
if (start == 1) {
sb.append('-');
}
sb.append('1');
for (int n = start; n < s.length(); n++) {
sb.append(s.charAt(n) == '.' ? '.' : '0');
}
trial = new BigDecimal(sb.toString());
} else {
// try rounding up
while (i >= 0 && (s.charAt(i) == '9' || s.charAt(i) == '.')) {
i--;
}
if (i < 0 || s.charAt(i) == '-') {
return initial; // can't happen: we've already handled numbers starting 99999..
} else if (p < 0 || i < p) {
// we're in the integer part
FastStringBuffer sb = new FastStringBuffer(s.length());
sb.append(s.substring(0, i));
sb.append((char) ((int) s.charAt(i) + 1));
for (int n = i; n < s.length(); n++) {
sb.append(s.charAt(n) == '.' ? '.' : '0');
}
trial = new BigDecimal(sb.toString());
} else {
// we're in the fractional part - can ignore following digits
String s2 = s.substring(0, i) + (char) ((int) s.charAt(i) + 1);
trial = new BigDecimal(s2);
}
}
}
}
if (trial != null
&& (precision == 1 ? trial.floatValue() == value : trial.doubleValue() == value)) {
return trial;
} else {
return initial;
}
}
