Parser

Main.java

import java.io.*;

/**
 * @author John Godman
 * Simple file token parser.
 */
public class Main

{
    public static final int BUF_SIZE = 80,
                                 EOF = -1, // end of file  see javadoc
                            NO_VALUE = -1,
                     TOKENS_PER_LINE = 3; // how many tokens to print on each line
    public static final String  PATH = "/home/john/Documents/projects/test/input.txt";

    public static void main(String[] args) throws FileNotFoundException,
                                                  IOException
    {
        // input file
        File           filein = new File(PATH);
        FileReader     fileDS = new FileReader(filein);
        BufferedReader rdr    = new BufferedReader(fileDS);

        char[] buffer = new char[BUF_SIZE];
        int offset = 0, tokenStart = NO_VALUE, tokenEnd = NO_VALUE, // offset + token ptrs
                                       tokenCount = 0;

        while (rdr.read(buffer, offset, (BUF_SIZE - offset)) != EOF)
        {
            offset = 0; // reset our offset

            for (int i = 0; i < BUF_SIZE; i++)
            {
                if (buffer[i] != ' ') // delimiter
                {
                    if (tokenStart == NO_VALUE)
                        tokenStart = i;

                    if (buffer[i] == 0)
                        tokenEnd = i;
                } else
                    tokenEnd = i;

                if (tokenEnd != NO_VALUE)
                {
                    for (int j = tokenStart; j < tokenEnd; j++)
                        System.out.print(buffer[j]);

                    System.out.print(" ");

                    if (++tokenCount == TOKENS_PER_LINE)
                    {
                        System.out.println();
                        tokenCount = 0;
                    }
                    tokenStart = tokenEnd = NO_VALUE; // reset token ptrs
                }
            }

            char[] tempbuf = new char[BUF_SIZE]; // create a temporary buffer for swapping
            if (tokenStart != NO_VALUE && tokenEnd == NO_VALUE)
            { // place tail token into head of buffer & offset the next read
                int k;
                for (k = tokenStart; k < BUF_SIZE; k++)
                    tempbuf[k - tokenStart] = buffer[k];

                offset = k - tokenStart;
            }

            buffer = tempbuf;
            tokenStart = tokenEnd = NO_VALUE; // reset token ptrs
        }

        rdr.close();
        fileDS.close();

        return;
    }
}