Module ch.randelshofer.fastdoubleparser

Package ch.randelshofer.fastdoubleparser

Class ParseDigitsTaskByteArray

java.lang.Object

ch.randelshofer.fastdoubleparser.ParseDigitsTaskByteArray

final class ParseDigitsTaskByteArray
extends Object

Parses digits.

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
(package private) static BigInteger	parseDigitsIterative(byte[] str, int from, int to)	Parses digits in quadratic time O(N2).
(package private) static BigInteger	parseDigitsRecursive(byte[] 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 java.lang.Object

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

Constructor Details

ParseDigitsTaskByteArray

private ParseDigitsTaskByteArray()

Don't let anyone instantiate this class.

Method Details

parseDigitsIterative

static BigInteger parseDigitsIterative(byte[] str,
 int from,
 int to)

Parses digits in quadratic time O(N²).

parseDigitsRecursive

static BigInteger parseDigitsRecursive(byte[] 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 using FftMultiplier.