/**
* Takes a codepoint and returns its correspondent UTF-8 encoded character.
* Astral planes are supported, ie the intger input can be > 0xFFFF. Occurrances of the BOM are ignored.
* Surrogates are not allowed.
* @param int $codepoint The Unicode codepoint.
* @return string Returns the corresponding UTF-8 character.
* @author Henri Sivonen, mailto:hsivonen@iki.fi
* @link http://hsivonen.iki.fi/php-utf8/
* @author Ivan Tcholakov, 2009, modifications for the Dokeos LMS.
* @see _api_utf8_from_unicode()
* This is a UTF-8 aware version of the function chr().
* @link http://php.net/manual/en/function.chr.php
*/
function _api_utf8_chr($codepoint)
{
// ASCII range (including control chars)
if ($codepoint >= 0 && $codepoint <= 0x7f) {
$result = chr($codepoint);
// 2 byte sequence
} else {
if ($codepoint <= 0x7ff) {
$result = chr(0xc0 | $codepoint >> 6) . chr(0x80 | $codepoint & 0x3f);
// Byte order mark (skip)
} else {
if ($codepoint == 0xfeff) {
// nop -- zap the BOM
$result = '';
// Test for illegal surrogates
} else {
if ($codepoint >= 0xd800 && $codepoint <= 0xdfff) {
// found a surrogate
$result = _api_utf8_chr(0xfffd);
// U+FFFD REPLACEMENT CHARACTER is the general substitute character in the Unicode Standard.
// 3 byte sequence
} else {
if ($codepoint <= 0xffff) {
$result = chr(0xe0 | $codepoint >> 12) . chr(0x80 | $codepoint >> 6 & 0x3f) . chr(0x80 | $codepoint & 0x3f);
// 4 byte sequence
} else {
if ($codepoint <= 0x10ffff) {
$result = chr(0xf0 | $codepoint >> 18) . chr(0x80 | $codepoint >> 12 & 0x3f) . chr(0x80 | $codepoint >> 6 & 0x3f) . chr(0x80 | $codepoint & 0x3f);
} else {
// out of range
$result = _api_utf8_chr(0xfffd);
}
}
}
}
}
}
return $result;
}
/**
* Finds first occurrence of a string within another.
* @param string $haystack The string from which to get the first occurrence.
* @param mixed $needle The string to be found.
* @param bool $before_needle (optional) Determines which portion of $haystack this function returns. The default value is FALSE.
* @param string $encoding (optional) The used internally by this function character encoding. If it is omitted, the platform character set will be used by default.
* @return mixed Returns the portion of $haystack, or FALSE if $needle is not found.
* Notes:
* If $needle is not a string, it is converted to an integer and applied as the ordinal value (codepoint if the encoding is UTF-8) of a character.
* If $before_needle is set to TRUE, the function returns all of $haystack from the beginning to the first occurrence of $needle.
* If $before_needle is set to FALSE, the function returns all of $haystack from the first occurrence of $needle to the end.
* This function is aimed at replacing the functions strstr() and mb_strstr() for human-language strings.
* @link http://php.net/manual/en/function.strstr
* @link http://php.net/manual/en/function.mb-strstr
*/
function api_strstr($haystack, $needle, $before_needle = false, $encoding = null)
{
if (empty($encoding)) {
$encoding = _api_mb_internal_encoding();
}
if (!is_string($needle)) {
$needle = (int) $needle;
if (api_is_utf8($encoding)) {
$needle = _api_utf8_chr($needle);
} else {
$needle = chr($needle);
}
}
if ($needle == '') {
return false;
}
if (_api_is_single_byte_encoding($encoding)) {
return strstr($haystack, $needle, $before_needle);
}
if (_api_mb_supports($encoding)) {
return mb_strstr($haystack, $needle, $before_needle, $encoding);
}
return strstr($haystack, $needle, $before_needle);
}
