note 102335 deleted from function.strpos by thiago

Note Submitter: jaimthorn at yahoo dot com 

----

An complete set of strn*pos functions that look for the nth occurrence of the needle in the haystack. Based on a version I posted earlier, below; the new version conforms more to the semantics of strpos.

<?php

/**
 *  This function implements all the strn*pos functions, which return the $nth occurrence of $needle
 *  in $haystack, or false if it doesn't exist / when illegal parameters have been supplied.
 *
 *  @param  string  $haystack       the string to search in.
 *  @param  MIXED   $needle         the string or the ASCII value of the character to search for.
 *  @param  integer $nth            the number of the occurrence to look for.
 *  @param  integer $offset         the position in $haystack to start looking for $needle.
 *  @param  bool    $insensitive    should the function be case insensitive?
 *  @param  bool    $reverse        should the function work its way backwards in the haystack?
 *  @return MIXED   integer         either the position of the $nth occurrence of $needle in $haystack,
 *               or boolean         false if it can't be found.
 */
function strnripos_generic( $haystack, $needle, $nth, $offset, $insensitive, $reverse )
{
    //  If needle is not a string, it is converted to an integer and applied as the ordinal value of a character.
    if( ! is_string( $needle ) ) {
        $needle = chr( (int) $needle );
    }

    //  Are the supplied values valid / reasonable?
    $len = strlen( $needle );
    if( 1 > $nth || 0 === $len ) {
        return false;
    }

    if( $insensitive ) {
        $haystack = strtolower( $haystack );
        $needle   = strtolower( $needle   );
    }

    if( $reverse ) {
        $haystack = strrev( $haystack );
        $needle   = strrev( $needle   );
    }

    //  $offset is incremented in the call to strpos, so make sure that the first
    //  call starts at the right position by initially decreasing $offset by $len.
    $offset -= $len;
    do
    {
        $offset = strpos( $haystack, $needle, $offset + $len );
    } while( --$nth  && false !== $offset );

    return false === $offset || ! $reverse ? $offset : strlen( $haystack ) - $offset;
}

/**
 *  @see    strnripos_generic
 */
function strnpos( $haystack, $needle, $nth, $offset = 0 )
{
    return strnripos_generic( $haystack, $needle, $nth, $offset, false, false );
}

/**
 *  @see    strnripos_generic
 */
function strnipos( $haystack, $needle, $nth, $offset = 0 )
{
    return strnripos_generic( $haystack, $needle, $nth, $offset, true, false );
}

/**
 *  @see    strnripos_generic
 */
function strnrpos( $haystack, $needle, $nth, $offset = 0 )
{
    return strnripos_generic( $haystack, $needle, $nth, $offset, false, true );
}

/**
 *  @see    strnripos_generic
 */
function strnripos( $haystack, $needle, $nth, $offset = 0 )
{
    return strnripos_generic( $haystack, $needle, $nth, $offset, true, true );
}

$haystack = 'Dit is een HoTtentotTentenTentenToonstellingTest!';

echo strnpos  ( $haystack, 't', 5 ), ' === ', strnpos  ( $haystack, 116, 5 ), PHP_EOL;
echo strnipos ( $haystack, 't', 5 ), ' === ', strnipos ( $haystack, 116, 5 ), PHP_EOL;
echo strnrpos ( $haystack, 't', 5 ), ' === ', strnrpos ( $haystack, 116, 5 ), PHP_EOL;
echo strnripos( $haystack, 't', 5 ), ' === ', strnripos( $haystack, 116, 5 ), PHP_EOL;
echo PHP_EOL;
echo strnpos  ( $haystack, 'T', 5 ), ' === ', strnpos  ( $haystack,  84, 5 ), PHP_EOL;
echo strnipos ( $haystack, 'T', 5 ), ' === ', strnipos ( $haystack,  84, 5 ), PHP_EOL;
echo strnrpos ( $haystack, 'T', 5 ), ' === ', strnrpos ( $haystack,  84, 5 ), PHP_EOL;
echo strnripos( $haystack, 'T', 5 ), ' === ', strnripos( $haystack,  84, 5 ), PHP_EOL;