modules/upside_down/upside_down.module

<?php
// $Id$

/**
 * Implementation of hook_filter_tips().
 */
function upside_down_filter_tips($delta, $format, $long = FALSE) {
  return t('All text will be flipped and displayed upside down.');
}

/**
 * Implementation of hook_filter().
 */
function upside_down_filter($op, $delta = 0, $format = -1, $text = '') {
  switch ($op) {
    case 'list':
      return array(
        0 => t('Upside down filter'),
      );

    case 'description':
      return t('Flips text upside down. Currently only works with the simple roman alphabet and basic punctuation.');

    case 'process':
      $text = upside_down_flip_text($text);
      return $text;

    default:
      return $text;
  }
}

/**
 * Helper function for upside_down_filter() - flips the text.
 *
 * @param $text
 *   The text to flip.
 * @return
 *   The flipped text.
 */
function upside_down_flip_text($text) {
  $map = array(
    'a' => 0x0250,
    'b' => 'q',
    'c' => 0x0254,
    'd' => 'p',
    'e' => 0x01DD,
    'f' => 0x025F,
    'g' => 0x0183,
    'h' => 0x0265,
    'i' => 0x0131,
    'j' => 0x027E,
    'k' => 0x029E,
    'l' => 0x0283,
    'm' => 0x026F,
    'n' => 'u',
    'r' => 0x0279,
    't' => 0x0287,
    'v' => 0x028C,
    'w' => 0x028D,
    'y' => 0x028E,
    '.' => 0x02D9,
    '[' => ']',
    '(' => ')',
    '{' => '}',
    '?' => 0x00BF,
    '!' => 0x00A1,
    "'" => ',',
    '<' => '>',
    '_' => 0x203E,
    ';' => '!',
    0x203F => 0x2040,
    0x2045 => 0x2046,
    0x2234 => 0x2235,
  );
  $map += array_flip($map);
  $text = strrev($text);
  $lower = strtolower($text);
  $new_text = '';
  for ($i = 0; $i < strlen($text); $i++) {
    if (isset($map[$lower[$i]])) {
      $new_text .= is_numeric($map[$lower[$i]]) ? _upside_down_unicode_to_utf8($map[$lower[$i]]) : $map[$lower[$i]];
    }
    else {
      $new_text .= $text[$i];
    }
  }
  return $new_text;
}

/**
 * Helper function for upside_down_flip_text() - convert unicode entities to
 * utf8.
 *
 * @param $char
 *   The character to convert.
 * @return
 *   The converted character.
 */
function _upside_down_unicode_to_utf8($char) {
  $output = '';
  if ($char < 0x80) {
    return chr($char);
  }
  elseif ($char < 0x800) {
    return chr(0xc0 | ($char >> 6)) . chr(0x80 | ($char & 0x3f));
  }
  elseif ($char < 0x10000) {
    return chr(0xe0 | ($char >> 12)) . chr(0x80 | (($char >> 6) & 0x3f)) . chr(0x80 | ($char & 0x3f));
  }
  elseif ($char < 0x200000) {
    return chr(0xf0 | ($char >> 18)) . chr(0x80 | (($char >> 12) & 0x3f)) . chr(0x80 | (($char >> 6) & 0x3f)) . chr(0x80 | ($char & 0x3f));
  }
  return '';
}
1	<?php
2	// $Id$
3
4	/**
5	* Implementation of hook_filter_tips().
6	*/
7	function upside_down_filter_tips($delta, $format, $long = FALSE) {
8	return t('All text will be flipped and displayed upside down.');
9	}
10
11	/**
12	* Implementation of hook_filter().
13	*/
14	function upside_down_filter($op, $delta = 0, $format = -1, $text = '') {
15	switch ($op) {
16	case 'list':
17	return array(
18	0 => t('Upside down filter'),
19	);
20
21	case 'description':
22	return t('Flips text upside down. Currently only works with the simple roman alphabet and basic punctuation.');
23
24	case 'process':
25	$text = upside_down_flip_text($text);
26	return $text;
27
28	default:
29	return $text;
30	}
31	}
32
33	/**
34	* Helper function for upside_down_filter() - flips the text.
35	*
36	* @param $text
37	* The text to flip.
38	* @return
39	* The flipped text.
40	*/
41	function upside_down_flip_text($text) {
42	$map = array(
43	'a' => 0x0250,
44	'b' => 'q',
45	'c' => 0x0254,
46	'd' => 'p',
47	'e' => 0x01DD,
48	'f' => 0x025F,
49	'g' => 0x0183,
50	'h' => 0x0265,
51	'i' => 0x0131,
52	'j' => 0x027E,
53	'k' => 0x029E,
54	'l' => 0x0283,
55	'm' => 0x026F,
56	'n' => 'u',
57	'r' => 0x0279,
58	't' => 0x0287,
59	'v' => 0x028C,
60	'w' => 0x028D,
61	'y' => 0x028E,
62	'.' => 0x02D9,
63	'[' => ']',
64	'(' => ')',
65	'{' => '}',
66	'?' => 0x00BF,
67	'!' => 0x00A1,
68	"'" => ',',
69	'<' => '>',
70	'_' => 0x203E,
71	';' => '!',
72	0x203F => 0x2040,
73	0x2045 => 0x2046,
74	0x2234 => 0x2235,
75	);
76	$map += array_flip($map);
77	$text = strrev($text);
78	$lower = strtolower($text);
79	$new_text = '';
80	for ($i = 0; $i < strlen($text); $i++) {
81	if (isset($map[$lower[$i]])) {
82	$new_text .= is_numeric($map[$lower[$i]]) ? _upside_down_unicode_to_utf8($map[$lower[$i]]) : $map[$lower[$i]];
83	}
84	else {
85	$new_text .= $text[$i];
86	}
87	}
88	return $new_text;
89	}
90
91	/**
92	* Helper function for upside_down_flip_text() - convert unicode entities to
93	* utf8.
94	*
95	* @param $char
96	* The character to convert.
97	* @return
98	* The converted character.
99	*/
100	function _upside_down_unicode_to_utf8($char) {
101	$output = '';
102	if ($char < 0x80) {
103	return chr($char);
104	}
105	elseif ($char < 0x800) {
106	return chr(0xc0 \| ($char >> 6)) . chr(0x80 \| ($char & 0x3f));
107	}
108	elseif ($char < 0x10000) {
109	return chr(0xe0 \| ($char >> 12)) . chr(0x80 \| (($char >> 6) & 0x3f)) . chr(0x80 \| ($char & 0x3f));
110	}
111	elseif ($char < 0x200000) {
112	return chr(0xf0 \| ($char >> 18)) . chr(0x80 \| (($char >> 12) & 0x3f)) . chr(0x80 \| (($char >> 6) & 0x3f)) . chr(0x80 \| ($char & 0x3f));
113	}
114	return '';
115	}