// MakeCode prompts the user for an input file name and a code file name.  It
// examines the input file for the frequencies of characters and then uses a
// Huffman tree to generate codes to use for each character so as to compress
// the original file.  This program does not the actual encoding or decoding.

import java.io.*;
import java.util.*;

public class MakeCode {
    public static final int CHAR_MAX = 256;  // max char value to be encoded

    public static void main(String[] args) throws IOException {
        System.out.println("This program makes a Huffman code for a file.");
        System.out.println();

        // get file names from user
        Scanner console = new Scanner(System.in);
        System.out.print("input file name? ");
        String inFile = console.nextLine();
        System.out.print("code file name? ");
        String codeFile = console.nextLine();

        // open input file and count character frequencies
        FileInputStream input = new FileInputStream(inFile);
        int[] count = new int[CHAR_MAX];
        int n = input.read();
        while (n != -1) {
            count[n]++;
            n = input.read();
        }

        // build tree, open output file, print codes
        HuffmanTree t = new HuffmanTree(count);
        PrintStream output = new PrintStream(new File(codeFile));
        t.write(output);
    }
}