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A Unicode fgetc() in PHP

In preparation for a presentation I’m giving at this month’s Syracuse PHP Users Group meeting, I found the need to read in Unicode characters in PHP one at a time. Unicode is still second-class in PHP; PHP6 failed and we have to fallback to extensions like the mbstring extension and/or libraries like Portable UTF-8. And even with those, I didn’t see a unicode-capable fgetc() so I wrote my own.

Years ago, I wrote a post describing how to read Unicode characters in C, so the logic was already familiar. As a refresher, UTF-8 is a multi-byte encoding scheme capable of representing over 2 million characters using 4 bytes or less. The first 128 characters are encoded the same as 7-bit ASCII with 0 as the most-significant bit. The other characters are encoded using multiple bytes, each byte with 1 as the most-significant bit. The bit pattern in the first byte of a multi-byte sequence tells us how many bytes are needed to represent the character.

Here’s what the function looks like:

function ufgetc($fp)
    // mask values for first byte's bit patterns
    static $mask = [
        192, // 110xxxxx
        224, // 1110xxxx
        240  // 11110xxx

    // read first byte
    $ch = fgetc($fp);
    if ($ch === false) {
        // return false on EOF
        return false;

    // single-byte character
    if ((ord($ch) & $mask[0]) != $mask[0]) {
        return $ch;

    // multi-byte character
    $buf = $ch;
    for ($i = 0; $i < count($mask); $i++) {
        if ((ord($ch) & $mask[$i]) != $mask[$i]) {
        $buf .= fgetc($fp);
    return $buf;
PHP’s fgetc() reads in 8 bits at a time just like it’s counterpart in C, but these bytes are represented as a single-character string in PHP’s type system so we need to use the byte’s integer value for the mask check to succeed.


  1. Hi Timothy, thanks for sharing the code, saved me a lot of time !
    regards Lars


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