//  $Id: string.js,v 1.4 2002/02/20 18:42:46 nwiggins Exp $
//
//  $Log: string.js,v $
//  Revision 1.4  2002/02/20 18:42:46  nwiggins
//
//  # removes script tags - forces usage as a javascript src include. no php includes
//
//  Revision 1.3  2001/07/18 23:07:57  jneil
//  Fixed some problems.
//
//  Revision 1.2  2001/07/02 06:11:18  vhegde
//  Revision 1.1  2001/05/21 15:53:53  jneil
//  Initial Upload.
//
//

// whitespace characters: ' ', '\t', '\r', '\n'
var whitespace = " \t\n\r";

// isEmpty: Check whether string strVal is empty
function isEmpty(strVal)
{
	return ((strVal == null) || (strVal.length == 0));
}

// isWhitespace: Check if string strVal has only the whitespace characters
function isWhitespace(strVal)
{
	var nPos = 0;

	if (isEmpty(strVal))
		return false;

	for (nPos = 0; nPos < strVal.length; nPos++)
		if (whitespace.indexOf(strVal.charAt(nPos)) == -1)
			return false;

	return true;
}

// rtrim: Right trim the string and return the trimmed value
function rtrim(strVal)
{
	var nPos = 0;

	if (isEmpty(strVal))
		return strVal;

	for (nPos = strVal.length-1; nPos >= 0; nPos--) {
		if (whitespace.indexOf(strVal.charAt(nPos)) == -1)
			break;
	}

	return (nPos == strVal.length-1 ? strVal.substring(0) : strVal.substring(0, nPos+1));
}

// ltrim: Left trim the string and return the trimmed value
function ltrim(strVal)
{
	var nPos = 0;

	if (isEmpty(strVal))
		return strVal;

	for (nPos = 0; nPos < strVal.length; nPos++) {
		if (whitespace.indexOf(strVal.charAt(nPos)) == -1)
			break;
	}

	return strVal.substring(nPos);
}

// alltrim: Trim the string on left and right, and return the trimmed value
function alltrim(strVal)
{
	return (isEmpty(strVal) ? strVal:ltrim(rtrim(strVal)));
}

/********************************************************
 replace: useful for JavaScript 1.0 and 1.1 where replace 
	  is not available. With JavaScript 1.2 (and above)
	  replace function is available.
	: replaces one occurrence of strVal with strWith in strSrc
********************************************************/
function replace(strSrc, strVal, strWith)
{
	var nPos = 0, strLeft="", strRight="";

	// check if empty (or) no string is found to replace
	if (isEmpty(strSrc) || (strSrc.indexOf(strVal) < 0))
		return strSrc;

	nPos = strSrc.indexOf(strVal);
	strLeft = strSrc.substring(0, nPos);
	nPos += strVal.length;
	strRight = strSrc.substring(nPos);

	return (strLeft + strWith + strRight);
}

// replaceall : replace all occurrences of strVal with strWith in strSrc
function replaceall(strSrc, strVal, strWith)
{
	var strBuffer=strSrc;

	while (strBuffer.indexOf(strVal) >= 0)
		strBuffer = replace(strBuffer, strVal, strWith);

	return (strBuffer);
}

// occurs: return no of occurrences of strVal within strSrc
function occurs(strVal, strSrc)
{
	var nCnt = 0, strBuffer=strSrc;

	while (strBuffer.indexOf(strVal) >= 0)
	{
		strBuffer = replace(strBuffer, strVal, "");
		nCnt++;
	}

	return (nCnt);
}

// replicate: returns string that contains strVal repeated nCnt times
function replicate(strVal, nCnt)
{
	var i = 0, strBuffer = "";

	for (i = 0; i < nCnt; i++)
		strBuffer += strVal;

	return (strBuffer);
}

/**************************************************************
 stuff: returns string after replacing nCnt characters (starting
	from nStartPos) with strReplacement in strSrc. 

 NOTE: starting position is 0
**************************************************************/
function stuff(strSrc, nStartPos, nCnt, strReplacement)
{
	var strLeft= "", strRight="";

	// check boundary values
	if (nCnt < 0 || nStartPos < 0 || (nStartPos > strSrc.length-1))
		return strSrc;

	strLeft = strSrc.substring(0, nStartPos);
	strRight = strSrc.substring(nStartPos+nCnt);

	return (strLeft + strReplacement + strRight);
}