// -----------------------------------------------------------------------------
// ReadFileIntoByteArray.java
// -----------------------------------------------------------------------------

/*
 * =============================================================================
 * Copyright (c) 1998-2008 Jeffrey M. Hunter. All rights reserved.
 * 
 * All source code and material located at the Internet address of
 * http://www.idevelopment.info is the copyright of Jeffrey M. Hunter and
 * is protected under copyright laws of the United States. This source code may
 * not be hosted on any other site without my express, prior, written
 * permission. Application to host any of the material elsewhere can be made by
 * contacting me at jhunter@idevelopment.info.
 *
 * I have made every effort and taken great care in making sure that the source
 * code and other content included on my web site is technically accurate, but I
 * disclaim any and all responsibility for any loss, damage or destruction of
 * data or any other property which may arise from relying on it. I will in no
 * case be liable for any monetary damages arising from such loss, damage or
 * destruction.
 * 
 * As with any code, ensure to test this code in a development environment 
 * before attempting to run it in production.
 * =============================================================================
 */
 
import java.io.File;
import java.io.InputStream;
import java.io.FileInputStream;
import java.io.IOException;

/**
 * -----------------------------------------------------------------------------
 * This program demonstrates how to read a file into a byte array. This method
 * reads the entire contents of the file into a byte array.
 * 
 * @version 1.0
 * @author  Jeffrey M. Hunter  (jhunter@idevelopment.info)
 * @author  http://www.idevelopment.info
 * -----------------------------------------------------------------------------
 */

public class ReadFileIntoByteArray {


    /**
     * method to convert a byte to a hex string.
     *
     * @param data the byte to convert
     * @return String the converted byte
     */
    public static String byteToHex(byte data) {

        StringBuffer buf = new StringBuffer();
        buf.append(toHexChar((data >>> 4) & 0x0F));
        buf.append(toHexChar(data & 0x0F));

        return buf.toString();
    }


    /**
     * Convenience method to convert an int to a hex char.
     *
     * @param i the int to convert
     * @return char the converted char
     */
    public static char toHexChar(int i) {
        if ((0 <= i) && (i <= 9)) {
            return (char) ('0' + i);
        } else {
            return (char) ('a' + (i - 10));
        }
    }


    /**
     * Returns the contents of the file in a byte array
     * @param file File this method should read
     * @return byte[] Returns a byte[] array of the contents of the file
     */
    private static byte[] getBytesFromFile(File file) throws IOException {

        InputStream is = new FileInputStream(file);
        System.out.println("\nDEBUG: FileInputStream is " + file);

        // Get the size of the file
        long length = file.length();
        System.out.println("DEBUG: Length of " + file + " is " + length + "\n");

        /*
         * You cannot create an array using a long type. It needs to be an int
         * type. Before converting to an int type, check to ensure that file is
         * not loarger than Integer.MAX_VALUE;
         */
        if (length > Integer.MAX_VALUE) {
            System.out.println("File is too large to process");
            return null;
        }

        // Create the byte array to hold the data
        byte[] bytes = new byte[(int)length];

        // Read in the bytes
        int offset = 0;
        int numRead = 0;
        while ( (offset < bytes.length)
                &&
                ( (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) ) {

            offset += numRead;

        }

        // Ensure all the bytes have been read in
        if (offset < bytes.length) {
            throw new IOException("Could not completely read file " + file.getName());
        }

        is.close();
        return bytes;

    }


    /**
     * Sole entry point to the class and application.
     * @param args Array of String arguments.
     */
    public static void main(String[] args) {

        byte[] fileArray = null;

        try {
            fileArray = getBytesFromFile(new File("README_InputFile.txt"));
        } catch (IOException e) {
            e.printStackTrace();
        }

        if (fileArray != null) {
            for (int i=0; i<fileArray.length; i++) {

                System.out.println(
                    "fileArray[" + i + "] = " +
                    ((int)fileArray[i] < 9  ? "  " : "") +
                    ( ((int)fileArray[i] > 9 && (int)fileArray[i] <= 99) ? " " : "") +
                    fileArray[i] + " : " +
                    " HEX=(0x" + byteToHex(fileArray[i]) + ") : " +
                    " charValue=(" + (char)fileArray[i] + ")");
            }
        }

    }

}