Linear version of GStrings' most used parsing methods

linear_strings.php

<?php
/**
 * Deletes the right most string from the found search string
 * starting from right to left, including the search string itself.
 *
 * @return string
 */
function delRightMost( $sSource, $sSearch ) {
	for ( $i = strlen( $sSource ); $i >= 0; $i = $i - 1 ) {
		$f = strpos( $sSource, $sSearch, $i );
		if ( $f !== false ) {
			return substr( $sSource, 0, $f );
			break;
		}
	}
	return $sSource;
}

/**
 * Deletes the left most string from the found search string
 * starting from 
 *
 * @return string
 */
function delLeftMost( $sSource, $sSearch ) {
	for ( $i = 0; $i < strlen( $sSource ); $i = $i + 1 ) {
		$f = strpos( $sSource, $sSearch, $i );
		if ( $f !== false ) {
			return substr( $sSource, $f + strlen( $sSearch ), strlen( $sSource ) );
			break;
		}
	}
	return $sSource;
}

/**
 * Returns the right most string from the found search string
 * starting from right to left, excluding the search string itself.
 *
 * @return string
 */
function getRightMost( $sSource, $sSearch ) {
	for ( $i = strlen( $sSource ); $i >= 0; $i = $i - 1 ) {
		$f = strpos( $sSource, $sSearch, $i );
		if ( $f !== false ) {
			return substr( $sSource, $f + strlen( $sSearch ), strlen( $sSource ) );
		}
	}
	return $sSource;
}

/**
 * Returns the left most string from the found search string
 * starting from left to right, excluding the search string itself.
 *
 * @return string
 */
public function getLeftMost( $sSource, $sSearch ) {
	for ( $i = 0; $i < strlen( $sSource ); $i = $i + 1 ) {
		$f = strpos( $sSource, $sSearch, $i );
		if ( $f !== false ) {
			return substr( $sSource, 0, $f );
			break;
		}
	}
	return $sSource;
}

function replaceFirst( $haystack, $needle, $replace ) {
    $pos = strpos( $haystack, $needle );
    if ($pos !== false) {
	$newstring = substr_replace( $haystack, $replace, $pos, strlen( $needle ) );
    }else{
        $newstring = $haystack;
    }
    return $newstring;
}

function replaceLast( $haystack, $needle, $replace ) {
    $pos = strrpos( $haystack, $needle );
    if ($pos !== false) {
	$newstring = substr_replace( $haystack, $replace, $pos, strlen( $needle ) );
    }else{
    	$newstring = $haystack;
    }
    return $newstring;
}