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--TEST--
PDO_MYSQL: Test quoting of multibyte sequence with GBK vs utf8mb4
--EXTENSIONS--
pdo_mysql
--SKIPIF--
<?php
require_once __DIR__ . '/inc/mysql_pdo_test.inc';
MySQLPDOTest::skip();
?>
--FILE--
<?php
require_once __DIR__ . '/inc/mysql_pdo_test.inc';
$link = MySQLPDOTest::factory('PDO', ['charset' => 'GBK']);
$quoted = $link->quote("\xbf\x27");
$quoted_without_outer_quotes = substr($quoted, 1, -1);
/* This should result in 5C BF 5C 27 for GBK instead of BF 5C 27 like with UTF8MB4.
* To explain why the extra escaping takes place, let's assume we don't do that and see what happens.
*
* 1. First iteration, i.e. *from == 0xBF. This isn't a valid GBK multibyte sequence start,
* so the mb validity check fails.
* Without the character length check, we'd check if we need to escape the current character 0xBF.
* The character 0xBF isn't handled in the switch case so we don't escape it and append 0xBF to the output buffer.
* 2. Second iteration, i.e. *from == 0x27. This isn't a valid start either, so we go to the escape logic.
* Note that 0x27 is the character ', so we have to escape! We write two bytes to the output:
* \ (this is 0x5C) and ' (this is 0x27).
* 3. The function finished, let's look at the output: 0xBF 0x5C 0x27.
* Now we actually made a problem: 0xBF 0x5C is a valid GBK multibyte sequence!
* So we transformed an invalid multibyte sequences into a valid one, potentially corrupting data.
* The solution is to check whether it could have been part of a multibyte sequence, but the checks are less strict. */
var_dump(bin2hex($quoted_without_outer_quotes));
unset($link);
// Compare with utf8mb4
$link = MySQLPDOTest::factory('PDO', ['charset' => 'utf8mb4']);
$quoted = $link->quote("\xbf\x27");
$quoted_without_outer_quotes = substr($quoted, 1, -1);
var_dump(bin2hex($quoted_without_outer_quotes));
?>
--EXPECT--
string(8) "5cbf5c27"
string(6) "bf5c27"
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