Question

seems_utf8( string $str )

Checks to see if a string is utf8 encoded.

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description

NOTE: This function checks for 5-Byte sequences, UTF8 has Bytes Sequences with a maximum length of 4.

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参数

$str

(string) (Required) The string to be checked

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返回值

(bool) True if $str fits a UTF-8 model, false otherwise.

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源代码

File: wp-includes/formatting.php

function seems_utf8( $str ) {
	mbstring_binary_safe_encoding();
	$length = strlen($str);
	reset_mbstring_encoding();
	for ($i=0; $i < $length; $i++) {
		$c = ord($str[$i]);
		if ($c < 0x80) $n = 0; // 0bbbbbbb
		elseif (($c & 0xE0) == 0xC0) $n=1; // 110bbbbb
		elseif (($c & 0xF0) == 0xE0) $n=2; // 1110bbbb
		elseif (($c & 0xF8) == 0xF0) $n=3; // 11110bbb
		elseif (($c & 0xFC) == 0xF8) $n=4; // 111110bb
		elseif (($c & 0xFE) == 0xFC) $n=5; // 1111110b
		else return false; // Does not match any model
		for ($j=0; $j<$n; $j++) { // n bytes matching 10bbbbbb follow ?
			if ((++$i == $length) || ((ord($str[$i]) & 0xC0) != 0x80))
				return false;
		}
	}
	return true;
}

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更新日志

Version	description
1.2.1	Introduced.

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相关函数

Uses

• wp-includes/functions.php: mbstring_binary_safe_encoding()
• wp-includes/functions.php: reset_mbstring_encoding()

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Used By

• wp-admin/includes/export.php: wxr_cdata()
• wp-admin/includes/image.php: wp_read_image_metadata()
• wp-includes/formatting.php: sanitize_title_with_dashes()
• wp-includes/formatting.php: remove_accents()

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User Contributed Notes