note 72274 modified in function.strlen by danbrown

Title: Strlen() ant bytes string lenght. Just to remember that strlen() return the number of characters of a string. Often the strlen() function is used to compute the length in bytes of a string. This is correct until string is single byte encoded. If multi-byte char-set is used this constraint i no more verified. So when you require the number of bytes of a ASCII or UTF-8 encoded string, it is better to use following function: <?php /** * Count the number of bytes of a given string. * Input string is expected to be ASCII or UTF-8 encoded. * Warning: the function doesn't return the number of chars * in the string, but the number of bytes. * * @param string $str The string to compute number of bytes * * @return The length in bytes of the given string. */ function strBytes($str) { // STRINGS ARE EXPECTED TO BE IN ASCII OR UTF-8 FORMAT // Number of characters in string $strlen_var = strlen($str); // string bytes counter $d = 0; /* * Iterate over every character in the string, * escaping with a slash or encoding to UTF-8 where necessary */ for ($c = 0; $c < $strlen_var; ++$c) { $ord_var_c = ord($str{$d}); switch (true) { case (($ord_var_c >= 0x20) && ($ord_var_c <= 0x7F)): // characters U-00000000 - U-0000007F (same as ASCII) $d++; break; case (($ord_var_c & 0xE0) == 0xC0): // characters U-00000080 - U-000007FF, mask 110XXXXX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $d+=2; break; case (($ord_var_c & 0xF0) == 0xE0): // characters U-00000800 - U-0000FFFF, mask 1110XXXX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $d+=3; break; case (($ord_var_c & 0xF8) == 0xF0): // characters U-00010000 - U-001FFFFF, mask 11110XXX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $d+=4; break; case (($ord_var_c & 0xFC) == 0xF8): // characters U-00200000 - U-03FFFFFF, mask 111110XX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $d+=5; break; case (($ord_var_c & 0xFE) == 0xFC): // characters U-04000000 - U-7FFFFFFF, mask 1111110X // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $d+=6; break; default: $d++; } } return $d; } ?> This function has been adapted form the JSON function used to convert character in UTF-8 representation. With this new function we solved problem in JSON and in PEAR/SOAP php libraries. --was-- Title: Strlen() ant bytes string lenght. Just to remember that strlen() return the number of characters of a string. Often the strlen() function is used to compute the length in bytes of a string. This is correct until string is single byte encoded. If multi-byte char-set is used this constraint i no more verified. So when you require the number of bytes of a ASCII or UTF-8 encoded string, it is better to use following function: /** * Count the number of bytes of a given string. * Input string is expected to be ASCII or UTF-8 encoded. * Warning: the function doesn't return the number of chars * in the string, but the number of bytes. * * @param string $str The string to compute number of bytes * * @return The length in bytes of the given string. */ function strBytes($str) { // STRINGS ARE EXPECTED TO BE IN ASCII OR UTF-8 FORMAT // Number of characters in string $strlen_var = strlen($str); // string bytes counter $d = 0; /* * Iterate over every character in the string, * escaping with a slash or encoding to UTF-8 where necessary */ for ($c = 0; $c < $strlen_var; ++$c) { $ord_var_c = ord($str{$d}); switch (true) { case (($ord_var_c >= 0x20) && ($ord_var_c <= 0x7F)): // characters U-00000000 - U-0000007F (same as ASCII) $d++; break; case (($ord_var_c & 0xE0) == 0xC0): // characters U-00000080 - U-000007FF, mask 110XXXXX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $d+=2; break; case (($ord_var_c & 0xF0) == 0xE0): // characters U-00000800 - U-0000FFFF, mask 1110XXXX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $d+=3; break; case (($ord_var_c & 0xF8) == 0xF0): // characters U-00010000 - U-001FFFFF, mask 11110XXX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $d+=4; break; case (($ord_var_c & 0xFC) == 0xF8): // characters U-00200000 - U-03FFFFFF, mask 111110XX // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $d+=5; break; case (($ord_var_c & 0xFE) == 0xFC): // characters U-04000000 - U-7FFFFFFF, mask 1111110X // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8 $d+=6; break; default: $d++; } } return $d; } This function has been adapted form the JSON function used to convert character in UTF-8 representation. With this new function we solved problem in JSON and in PEAR/SOAP php libraries. http://php.net/manual/en/function.strlen.php