PHP correctly parses UTF-8 string skills application

PHP correctly parses UTF-8 string skills application_PHP tutorial

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Release： 2016-07-21 15:15:14

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In "Learning PHP & MYSQL - Character Encoding (Part 1)", the conversion relationship between Unicode and UTF-8 is introduced, and a UTF-8 encoding rule is summarized. Based on this encoding rule, a UTF-8 encoding parsing program is written. , the following is the implementation of PHP:

Copy code The code is as follows:

/* 
Program function, $str is a UTF-8 encoded string mixed with Chinese and English. 
Decode and display this string correctly according to UTF-8 encoding rules. 
*/ 


$str = 'Today is very happy, so we decided to go to KFC to eat Coke chicken wings!!!'; 

/* 
$str is to be intercepted The string 
$len is the number of intercepted characters 
*/ 
function utf8sub($str,$len) { 
if($len <= 0){ 
return '' ; 
} 

$offset = 0; // Offset when intercepting high-order bytes 
$chars = 0; // Number of characters intercepted 
$res = '' ; // Store the intercepted result string 

while($chars < $len){ 
// Take the first byte of the string first 
// Convert it to decimal
// Then convert to binary 
$high = ord(substr($str,$offset,1)); 

// echo '$high='. $high .'
'; 

if($high == null ){ // If the high bit is null, it proves that it has been fetched to the end, break directly 
break; 
} 
if( ($high>>2) === 0x3F){ // Shift the high bit to the right by 2 bits and compare it with binary 111111. If it is the same, take 6 bytes
// Intercept 2 bytes
$count = 6; 
}else if(($high>>3) === 0x1F){ // Shift the high bit to the right by 2 bits and compare it with binary 11111. If it is the same, take 5 bytes 
// Intercept 3 bytes 
$count = 5; 
}else if(($high>>4) === 0xF){ // Shift the high bit to the right by 2 bits and compare it with binary 1111. If they are the same, then Take 4 bytes 

// Take 4 bytes 
$count = 4; 
}else if(($high>>5) === 0x7){ // Will Shift the high bit right by 2 bits and compare with binary 111. If it is the same, take 3 bytes 

// Intercept 5 bytes 
$count = 3; 
}else if(($high> >6) === 0x3){ // Shift the high bit to the right by 2 bits, compare with binary 11, if the same, take 2 bytes 
// Intercept 6 bytes 
$count = 2; 
}else if(($high>>7) === 0x0){ // Shift the high bit to the right by 2 bits and compare it with binary 0. If they are the same, take 1 byte 
$count = 1; 
} 
// echo '$count='.$count.'
'; 

$res .= substr($str,$offset,$count); / / Take out a character and connect it to $res string 
$chars += 1; // Number of intercepted characters + 1 
$offset += $count; // Intercept the high offset and move it backward by $count Bytes
} 
return $res; 
} 

echo utf8sub($str,100);