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MDL-5229 and MDL-6196 adding gb18030 mime header encoding; partial backport from MOODLE_18_STABLE

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skodak
2007-03-12 08:45:02 +00:00
parent f0b99a9fec
commit 8626d4bc24
1 changed files with 42 additions and 3 deletions
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lib/textlib.class.php
+42 -3
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@@ -189,11 +189,17 @@ class textlib {
return $result;
}
/* Generate a correct base64 encoded header to be used in MIME mail messages.
/**
* Generate a correct base64 encoded header to be used in MIME mail messages.
* This function seems to be 100% compliant with RFC1342. Credits go to:
* paravoid (http://www.php.net/manual/en/function.mb-encode-mimeheader.php#60283).
*/
function encode_mimeheader($text, $charset='utf-8') {
if (empty($text)) {
return (string)$text;
}
/// Normalize charset
$charset = $this->typo3cs->parse_charset($charset);
/// If the text is pure ASCII, we don't need to encode it
if ($this->convert($text, $charset, 'ascii') == $text) {
return $text;
@@ -209,11 +215,44 @@ class textlib {
/// Max line length is 75 (including start and end)
$length = 75 - strlen($start) - strlen($end);
/// Multi-byte ratio
$ratio = $this->strlen($text, $charset) / strlen($text);
$multilength = $this->strlen($text, $charset);
/// Detect if strlen and friends supported
if ($multilength === false) {
if ($charset == 'GB18030' or $charset == 'gb18030') {
while (strlen($text)) {
// try to encode first 22 chars - we expect most chars are two bytes long
if (preg_match('/^(([\x00-\x7f])|([\x81-\xfe][\x40-\x7e])|([\x81-\xfe][\x80-\xfe])|([\x81-\xfe][\x30-\x39]..)){1,22}/m', $text, $matches)) {
$chunk = $matches[0];
$encchunk = base64_encode($chunk);
if (strlen($encchunk) > $length) {
// find first 11 chars - each char in 4 bytes - worst case scenario
preg_match('/^(([\x00-\x7f])|([\x81-\xfe][\x40-\x7e])|([\x81-\xfe][\x80-\xfe])|([\x81-\xfe][\x30-\x39]..)){1,11}/m', $text, $matches);
$chunk = $matches[0];
$encchunk = base64_encode($chunk);
}
$text = substr($text, strlen($chunk));
$encoded .= ' '.$start.$encchunk.$end.$linefeed;
} else {
break;
}
}
$encoded = trim($encoded);
return $encoded;
} else {
return false;
}
}
$ratio = $multilength / strlen($text);
/// Base64 ratio
$magic = $avglength = floor(3 * $length * $ratio / 4);
/// basic infinite loop protection
$maxiterations = strlen($text)*2;
$iteration = 0;
/// Iterate over the string in magic chunks
for ($i=0; $i <= $this->strlen($text, $charset); $i+=$magic) {
for ($i=0; $i <= $multilength; $i+=$magic) {
if ($iteration++ > $maxiterations) {
return false; // probably infinite loop
}
$magic = $avglength;
$offset = 0;
/// Ensure the chunk fits in length, reduding magic if necessary