emoji_string.php

<?php

/**
 * json_encode function for non-standard string with 6byte emoji chars, like `\xed\xa0\xbd\xed\xb1\xa9`
 *
 * see https://github.com/amekkawi/diskusagereports/blob/master/scripts/inc/json_encode.php
 *
 */

/**
 * Based on Zend Framework's JSON encoding
 * Copyright (c) 2005-2010, Zend Technologies USA, Inc. All rights reserved.
 *
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 */
class EmojiString  {
    private $text;

    public function __construct($text) {
        $this->text = $text;
    }

    public function json_encode($value = NULL) {
        $value = is_null($value) ? $this->text : $value;
        if (is_object($value)) {
            return 'OBJECT not supported';
        } else if (is_array($value)) {
            return $this->_json_encode_encodeArray($value);
        }
        return $this->_json_encode_encodeDatum($value);
    }

    protected function _json_encode_encodeDatum(&$value) {
        $result = 'null';
        if (is_int($value) || is_float($value)) {
            $result = (string) $value;
            $result = str_replace(",", ".", $result);
        } elseif (is_string($value)) {
            $result = $this->_json_encode_encodeString($value);
        } elseif (is_bool($value)) {
            $result = $value ? 'true' : 'false';
        }
        return $result;
    }

    protected function _json_encode_encodeArray(&$array) {
        $tmpArray = array();
        // Check for associative array
        if (!empty($array) && (array_keys($array) !== range(0, count($array) - 1))) {
            // Associative array
            $result = '{';
            foreach ($array as $key => $value) {
                $key = (string) $key;
                $tmpArray[] = $this->_json_encode_encodeString($key)
                    . ':'
                    . $this->json_encode($value);
            }
            $result .= implode(',', $tmpArray);
            $result .= '}';
        } else {
            // Indexed array
            $result = '[';
            $length = count($array);
            for ($i = 0; $i < $length; $i++) {
                $tmpArray[] = json_encode($array[$i]);
            }
            $result .= implode(',', $tmpArray);
            $result .= ']';
        }
        return $result;
    }

    protected function _json_encode_encodeString(&$string) {
        // Escape these characters with a backslash:
        // " \ / \n \r \t \b \f
        $search  = array('\\', "\n", "\t", "\r", "\b", "\f", '"', '/');
        $replace = array('\\\\', '\\n', '\\t', '\\r', '\\b', '\\f', '\"', '\\/');
        $string  = str_replace($search, $replace, $string);
        // Escape certain ASCII characters:
        // 0x08 => \b
        // 0x0c => \f
        $string = str_replace(array(chr(0x08), chr(0x0C)), array('\b', '\f'), $string);
        $string = $this->_json_encode_encodeUnicodeString($string);
        return '"' . $string . '"';
    }

    protected function _json_encode_encodeUnicodeString($value) {
        $strlen_var = strlen($value);
        $ascii = "";
        /**
         * Iterate over every character in the string,
         * escaping with a slash or encoding to UTF-8 where necessary
         */
        for($i = 0; $i < $strlen_var; $i++) {
            $ord_var_c = ord($value[$i]);
            switch (true) {
            case (($ord_var_c >= 0x20) && ($ord_var_c <= 0x7F)):
                // characters U-00000000 - U-0000007F (same as ASCII)
                $ascii .= $value[$i];
                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
                $char = pack('C*', $ord_var_c, ord($value[$i + 1]));
                $i += 1;
                $utf16 = $this->_json_encode_utf82utf16($char);
                $ascii .= sprintf('\u%04s', bin2hex($utf16));
                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
                $char = pack('C*', $ord_var_c,
                    ord($value[$i + 1]),
                    ord($value[$i + 2]));
                $i += 2;
                $utf16 = $this->_json_encode_utf82utf16($char);
                $ascii .= sprintf('\u%04s', bin2hex($utf16));
                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
                $char = pack('C*', $ord_var_c,
                    ord($value[$i + 1]),
                    ord($value[$i + 2]),
                    ord($value[$i + 3]));
                $i += 3;
                $utf16 = $this->_json_encode_utf82utf16($char);
                $ascii .= sprintf('\u%04s', bin2hex($utf16));
                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
                $char = pack('C*', $ord_var_c,
                    ord($value[$i + 1]),
                    ord($value[$i + 2]),
                    ord($value[$i + 3]),
                    ord($value[$i + 4]));
                $i += 4;
                $utf16 = $this->_json_encode_utf82utf16($char);
                $ascii .= sprintf('\u%04s', bin2hex($utf16));
                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
                $char = pack('C*', $ord_var_c,
                    ord($value[$i + 1]),
                    ord($value[$i + 2]),
                    ord($value[$i + 3]),
                    ord($value[$i + 4]),
                    ord($value[$i + 5]));
                $i += 5;
                $utf16 = $this->_json_encode_utf82utf16($char);
                $ascii .= sprintf('\u%04s', bin2hex($utf16));
                break;
            }
        }
        return $ascii;
    }

    protected function _json_encode_utf82utf16($utf8) {
        // Check for mb extension otherwise do by hand.
        // if( function_exists('mb_convert_encoding') ) {
        //     return mb_convert_encoding($utf8, 'UTF-16', 'UTF-8');
        // }
        switch (strlen($utf8)) {
        case 1:
            // this case should never be reached, because we are in ASCII range
            // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
            return $utf8;
        case 2:
            // return a UTF-16 character from a 2-byte UTF-8 char
            // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
            return chr(0x07 & (ord($utf8{0}) >> 2))
                . chr((0xC0 & (ord($utf8{0}) << 6))
                | (0x3F & ord($utf8{1})));
        case 3:
            // return a UTF-16 character from a 3-byte UTF-8 char
            // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
            return chr((0xF0 & (ord($utf8{0}) << 4))
                | (0x0F & (ord($utf8{1}) >> 2)))
                . chr((0xC0 & (ord($utf8{1}) << 6))
                | (0x7F & ord($utf8{2})));
        }
        // ignoring UTF-32 for now, sorry
        return '';
    }
}

?>