/**
* Appends the textual representation of the specified <code>double</code> according to the
* specified formatting arguments.
*
* @param d the <code>double</code> value.
* @param digits the number of significative digits (excludes exponent) or <code>-1</code> to
* mimic the standard library (16 or 17 digits).
* @param scientific <code>true</code> to forces the use of the scientific notation (e.g. <code>
* 1.23E3</code>); <code>false</code> otherwise.
* @param showZero <code>true</code> if trailing fractional zeros are represented; <code>false
* </code> otherwise.
* @return <code>TypeFormat.format(d, digits, scientific, showZero, this)</code>
* @throws IllegalArgumentException if <code>(digits > 19)</code>)
*/
public final TextBuilder append(double d, int digits, boolean scientific, boolean showZero) {
if (digits > 19) throw new IllegalArgumentException("digits: " + digits);
if (d != d) // NaN
return append("NaN");
if (d == Double.POSITIVE_INFINITY) return append("Infinity");
if (d == Double.NEGATIVE_INFINITY) return append("-Infinity");
if (d == 0.0) { // Zero.
if (digits < 0) return append("0.0");
append('0');
if (showZero) {
append('.');
for (int j = 1; j < digits; j++) {
append('0');
}
}
return this;
}
if (d < 0) { // Work with positive number.
d = -d;
append('-');
}
// Find the exponent e such as: value == x.xxx * 10^e
int e = MathLib.floorLog10(d);
long m;
if (digits < 0) { // Use 16 or 17 digits.
// Try 17 digits.
long m17 = MathLib.toLongPow10(d, (17 - 1) - e);
// Check if we can use 16 digits.
long m16 = m17 / 10;
double dd = MathLib.toDoublePow10(m16, e - 16 + 1);
if (dd == d) { // 16 digits is enough.
digits = 16;
m = m16;
} else { // We cannot remove the last digit.
digits = 17;
m = m17;
}
} else // Use the specified number of digits.
m = MathLib.toLongPow10(d, (digits - 1) - e);
// Formats.
if (scientific || (e >= digits)) {
// Scientific notation has to be used ("x.xxxEyy").
long pow10 = POW10_LONG[digits - 1];
int k = (int) (m / pow10); // Single digit.
append((char) ('0' + k));
m = m - pow10 * k;
appendFraction(m, digits - 1, showZero);
append('E');
append(e);
} else { // Dot within the string ("xxxx.xxxxx").
int exp = digits - e - 1;
if (exp < POW10_LONG.length) {
long pow10 = POW10_LONG[exp];
long l = m / pow10;
append(l);
m = m - pow10 * l;
} else append('0'); // Result of the division by a power of 10 larger than any long.
appendFraction(m, exp, showZero);
}
return this;
}
