package util;



/**
 * String utility methods.
 * 
 * @author <a href="mailto:rana_b@yahoo.com">Rana Bhattacharyya</a>
 */

public
class StringUtils {

    private final static char SEPARATOR = '\n';

    /**
     * This is a string replacement method.
     */
    public static String replaceString(String source, String oldStr, String newStr) {
        StringBuffer sb = new StringBuffer(source.length());
        int sind = 0;
        int cind = 0;
        while ((cind=source.indexOf(oldStr, sind)) != -1) {
            sb.append(source.substring(sind, cind));
            sb.append(newStr);
            sind = cind + oldStr.length();
        }
        sb.append(source.substring(sind));
        return sb.toString();
    }


    /**
     * This method is used to insert HTML block dynamically
     *
     * @param source the HTML code to be processes
     * @param bReplaceNl if true '\n' will be replaced by <br>
     * @param bReplaceTag if true '<' will be replaced by &lt; and 
     *                          '>' will be replaced by &gt;
     * @param bReplaceQuote if true '\"' will be replaced by &quot; 
     */
    public static String formatHtml(String source, 
                                    boolean bReplaceNl, 
                                    boolean bReplaceTag,
                                    boolean bReplaceQuote) {

        StringBuffer sb = new StringBuffer();
        int len = source.length();
        for (int i=0; i<len; i++) {
            char c = source.charAt(i);
            switch (c) {
            case '\"':
                if (bReplaceQuote)sb.append("&quot;");
                else sb.append(c);
                break;

            case '<':
                if (bReplaceTag) sb.append("&lt;");
                else sb.append(c);
                break;

            case '>':
                if (bReplaceTag) sb.append("&gt;");
                else sb.append(c);
                break;

            case '\n':
                if (bReplaceNl) {
                    if (bReplaceTag) sb.append("&lt;br&gt;");
                    else sb.append("<br>");
                } else {
                    sb.append(c);                    
                }
                break;

            case '\r':
                break;

            case '&':
                sb.append("&amp;");
                break;

            default:
                sb.append(c);
                break;
            }
        }
        return sb.toString();
    } 
    
    /**
     * Pad string object
     */
    public static String pad(String src, 
                             char padChar, 
                             boolean rightPad, 
                             int totalLength) {
                             
        int srcLength = src.length();
        if (srcLength >= totalLength) {
            return src;
        }
        
        int padLength = totalLength - srcLength;
        StringBuffer sb = new StringBuffer(padLength);
        for(int i=0; i<padLength; ++i) {
            sb.append(padChar);
        }
        
        if (rightPad) {
            return src + sb.toString();
        }
        else {
            return sb.toString() + src;
        }
    }   
     
    /**
     * Get hex string from byte array
     */
    public static String toHexString(byte[] res) {
        StringBuffer sb = new StringBuffer(res.length << 1);
        for(int i=0; i<res.length; i++) {
            String digit = Integer.toHexString(0xFF & res[i]);
            if (digit.length() == 1) {
                digit = '0' + digit;
            }
            sb.append(digit);
        }
        return sb.toString().toUpperCase();
    } 
    
    /**
     * Get byte array from hex string
     */
    public static byte[] toByteArray(String hexString) {
        int arrLength = hexString.length() >> 1;
        byte buff[] = new byte[arrLength];
        for(int i=0; i<arrLength; i++) {
            int index = i << 1;
            String digit = hexString.substring(index, index+2);
            buff[i] = (byte)Integer.parseInt(digit, 16);
        }
        return buff;
    }    
       
}