public static List range(BigInteger start, BigInteger end) {
List l = new List();
long st = start.longValue();
long en = start.longValue();
if (BigInteger.valueOf(st).equals(start) && BigInteger.valueOf(en).equals(end)) {
int dir = st < en ? 1 : -1;
while (st != en) {
l.add(BigInteger.valueOf(st));
st = st + dir;
}
} else {
BigInteger dir;
if (start.compareTo(end) < 0) {
dir = BigInteger.ONE;
} else {
dir = BigInteger.valueOf(-1);
}
while (!start.equals(end)) {
l.add(start);
start = start.add(dir);
}
}
return l;
}
/** @see BigInteger#doubleValue() */
static double bigInteger2Double(BigInteger val) {
// val.bitLength() < 64
if ((val.numberLength < 2) || ((val.numberLength == 2) && (val.digits[1] > 0))) {
return val.longValue();
}
// val.bitLength() >= 33 * 32 > 1024
if (val.numberLength > 32) {
return ((val.sign > 0) ? Double.POSITIVE_INFINITY : Double.NEGATIVE_INFINITY);
}
int bitLen = val.abs().bitLength();
long exponent = bitLen - 1;
int delta = bitLen - 54;
// We need 54 top bits from this, the 53th bit is always 1 in lVal.
long lVal = val.abs().shiftRight(delta).longValue();
/*
* Take 53 bits from lVal to mantissa. The least significant bit is
* needed for rounding.
*/
long mantissa = lVal & 0x1FFFFFFFFFFFFFL;
if (exponent == 1023) {
if (mantissa == 0X1FFFFFFFFFFFFFL) {
return ((val.sign > 0) ? Double.POSITIVE_INFINITY : Double.NEGATIVE_INFINITY);
}
if (mantissa == 0x1FFFFFFFFFFFFEL) {
return ((val.sign > 0) ? Double.MAX_VALUE : -Double.MAX_VALUE);
}
}
// Round the mantissa
if (((mantissa & 1) == 1)
&& (((mantissa & 2) == 2) || BitLevel.nonZeroDroppedBits(delta, val.digits))) {
mantissa += 2;
}
mantissa >>= 1; // drop the rounding bit
long resSign = (val.sign < 0) ? 0x8000000000000000L : 0;
exponent = ((1023 + exponent) << 52) & 0x7FF0000000000000L;
long result = resSign | exponent | mantissa;
return Double.longBitsToDouble(result);
}
/**
* @return whether a BigDecimal is a valid Farrago decimal. If a BigDecimal's unscaled value
* overflows a long, then it is not a valid Farrago decimal.
*/
public static boolean isValidDecimal(BigDecimal bd) {
BigInteger usv = bd.unscaledValue();
long usvl = usv.longValue();
return usv.equals(BigInteger.valueOf(usvl));
}
