Java BigInteger to toPushbackReader(BigInteger x)

Description

to Pushback Reader

License

LGPL

Declaration

public static PushbackReader toPushbackReader(BigInteger x)
            throws IOException 

Method Source Code

//package com.java2s;
//License from project: LGPL 

import java.math.BigInteger;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PushbackReader;

import java.io.IOException;

public class Main {
    public static PushbackReader toPushbackReader(BigInteger x)
            throws IOException {
        byte[] bytes = x.abs().toByteArray();
        final int startB = (x.signum() < 0 ? '-' : -1); // Start the stream with minus sign in case of negative number
        InputStream in = new ByteArrayInputStream(bytes) {
            public int read() {
                int c;
                if (this.b == -1) {
                    this.b = super.read();
                    if (this.b == -1) {
                        c = -1;/*from   w  w w. j a  va 2 s .  co m*/
                    } else {
                        c = Character.forDigit(this.b >> 4, 16);
                        this.b = Character.forDigit(this.b & 0x0F, 16);
                    }
                } else {
                    c = this.b;
                    this.b = -1;
                }
                return c;
            }

            public int read(byte[] b, int off, int len) {
                int i = 0;
                for (; i < len; i++) {
                    int c = read();
                    if (c == -1) {
                        i = (i == 0 ? -1 : i); // In case of EOF; there was nothing to read in the stream
                        break;
                    }
                    b[i + off] = (byte) c;
                }
                return i;
            }

            private int b = startB;
        };

        return new PushbackReader(new InputStreamReader(in, "ISO-8859-1"));
    }
}

Related

1. toInteger(BigInteger integer)
2. toIntegerBytes(final BigInteger bigInt)
3. toMinimalByteArray(BigInteger value)
4. toObject(BigInteger x)
5. toPaddedBytes(BigInteger bi, int length)
6. toStr(BigInteger number)
7. toString(BigInteger bi)
8. toString(BigInteger[] vector)
9. toUnsigned(final BigInteger[] ulong)