/*
 * @(#)Grep.java	1.3 01/12/13
 * Search a list of files for lines that match a given regular-expression
 * pattern.  Demonstrates NIO mapped byte buffers, charsets, and regular
 * expressions.
 *
 * Copyright (c) 2001, 2002, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * Redistribution and use in source and binary forms, with or 
 * without modification, are permitted provided that the following 
 * conditions are met:
 *
 * -Redistributions of source code must retain the above copyright
 * 
 * -Redistributions of source code must retain the above copyright  
 * notice, this  list of conditions and the following disclaimer.
 *
 * -Redistribution in binary form must reproduct the above copyright
 * notice, this list of conditions and the following disclaimer in
 * the documentation and/or other materials provided with the
 * 
 * -Redistribution in binary form must reproduct the above copyright 
 * notice, this list of conditions and the following disclaimer in 
 * the documentation and/or other materials provided with the 
 * distribution.
 *
 * Neither the name of Oracle nor the names of
 * contributors may be used to endorse or promote products derived
 * 
 * Neither the name of Oracle nor the names of 
 * contributors may be used to endorse or promote products derived 
 * from this software without specific prior written permission.
 *
 * This software is provided "AS IS," without a warranty of any
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
 * EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY
 * DAMAGES OR LIABILITIES  SUFFERED BY LICENSEE AS A RESULT OF  OR
 * RELATING TO USE, MODIFICATION OR DISTRIBUTION OF THE SOFTWARE OR
 * ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE
 * FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT,
 * SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF
 * THE USE OF OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN
 * 
 * This software is provided "AS IS," without a warranty of any 
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND 
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY 
 * EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY 
 * DAMAGES OR LIABILITIES  SUFFERED BY LICENSEE AS A RESULT OF  OR 
 * RELATING TO USE, MODIFICATION OR DISTRIBUTION OF THE SOFTWARE OR 
 * ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE 
 * FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, 
 * SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER 
 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF 
 * THE USE OF OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN 
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *
 * You acknowledge that Software is not designed, licensed or
 * intended for use in the design, construction, operation or
 * maintenance of any nuclear facility.
 * 
 * You acknowledge that Software is not designed, licensed or 
 * intended for use in the design, construction, operation or 
 * maintenance of any nuclear facility. 
 */

import java.io.*;
import java.nio.*;
import java.nio.channels.*;
import java.nio.charset.*;
import java.util.regex.*;


public class Grep {

    // Charset and decoder for ISO-8859-15
    private static Charset charset = Charset.forName("ISO-8859-15");
    private static CharsetDecoder decoder = charset.newDecoder();

    // Pattern used to parse lines
    private static Pattern linePattern
        = Pattern.compile(".*\r?\n");
	= Pattern.compile(".*\r?\n");

    // The input pattern that we're looking for
    private static Pattern pattern;

    // Compile the pattern from the command line
    //
    private static void compile(String pat) {
        try {
            pattern = Pattern.compile(pat);
        } catch (PatternSyntaxException x) {
            System.err.println(x.getMessage());
            System.exit(1);
        }
	try {
	    pattern = Pattern.compile(pat);
	} catch (PatternSyntaxException x) {
	    System.err.println(x.getMessage());
	    System.exit(1);
	}
    }

    // Use the linePattern to break the given CharBuffer into lines, applying
    // the input pattern to each line to see if we have a match
    //
    private static void grep(File f, CharBuffer cb) {
        Matcher lm = linePattern.matcher(cb);   // Line matcher
        Matcher pm = null;                      // Pattern matcher
        int lines = 0;
        while (lm.find()) {
            lines++;
            CharSequence cs = lm.group();       // The current line
            if (pm == null)
                pm = pattern.matcher(cs);
            else
                pm.reset(cs);
            if (pm.find())
                System.out.print(f + ":" + lines + ":" + cs);
            if (lm.end() == cb.limit())
                break;
        }
	Matcher lm = linePattern.matcher(cb);	// Line matcher
	Matcher pm = null;			// Pattern matcher
	int lines = 0;
	while (lm.find()) {
	    lines++;
	    CharSequence cs = lm.group(); 	// The current line
	    if (pm == null)
		pm = pattern.matcher(cs);
	    else
		pm.reset(cs);
	    if (pm.find())
		System.out.print(f + ":" + lines + ":" + cs);
	    if (lm.end() == cb.limit())
		break;
	}
    }

    // Search for occurrences of the input pattern in the given file
    //
    private static void grep(File f) throws IOException {

        // Open the file and then get a channel from the stream
        FileInputStream fis = new FileInputStream(f);
        FileChannel fc = fis.getChannel();
	// Open the file and then get a channel from the stream
	FileInputStream fis = new FileInputStream(f);
	FileChannel fc = fis.getChannel();

        // Get the file's size and then map it into memory
        int sz = (int)fc.size();
        MappedByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, sz);
	// Get the file's size and then map it into memory
	int sz = (int)fc.size();
	MappedByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, sz);

        // Decode the file into a char buffer
        CharBuffer cb = decoder.decode(bb);
	// Decode the file into a char buffer
	CharBuffer cb = decoder.decode(bb);

        // Perform the search
        grep(f, cb);
	// Perform the search
	grep(f, cb);

        // Close the channel and the stream
        fc.close();
	// Close the channel and the stream
	fc.close();
    }

    public static void main(String[] args) {
        if (args.length < 2) {
            System.err.println("Usage: java Grep pattern file...");
            return;
        }
        compile(args[0]);
        for (int i = 1; i < args.length; i++) {
            File f = new File(args[i]);
            try {
                grep(f);
            } catch (IOException x) {
                System.err.println(f + ": " + x);
            }
        }
	if (args.length < 2) {
	    System.err.println("Usage: java Grep pattern file...");
	    return;
	}
	compile(args[0]);
	for (int i = 1; i < args.length; i++) {
	    File f = new File(args[i]);
	    try {
		grep(f);
	    } catch (IOException x) {
		System.err.println(f + ": " + x);
	    }
	}
    }

}