Class ParseDigitsTaskCharSequence

java.lang.Object

ch.randelshofer.fastdoubleparser.ParseDigitsTaskCharSequence

final class ParseDigitsTaskCharSequence
extends Object

Parses digits.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	ParseDigitsTaskCharSequence()	Don't let anyone instantiate this class.

Method Summary

Modifier and Type	Method	Description
(package private) static BigInteger	parseDigitsIterative(CharSequence str, int from, int to)	Parses digits in quadratic time O(N2).
(package private) static BigInteger	parseDigitsRecursive(CharSequence str, int from, int to, Map<Integer, BigInteger> powersOfTen, int recursionThreshold)	Parses digits in O(N log N (log log N)) time.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ParseDigitsTaskCharSequence

private ParseDigitsTaskCharSequence()

Don't let anyone instantiate this class.

Method Details

parseDigitsIterative

static BigInteger parseDigitsIterative(CharSequence str,
 int from,
 int to)

Parses digits in quadratic time O(N²).

parseDigitsRecursive

static BigInteger parseDigitsRecursive(CharSequence str,
 int from,
 int to,
 Map<Integer, BigInteger> powersOfTen,
 int recursionThreshold)

Parses digits in O(N log N (log log N)) time.

A conventional recursive algorithm would require O(N^1.5). We achieve better performance by performing multiplications of long bit sequences in the frequency domain.