今天coding时,需要将php中的变量返回给第三方,第一个想到就是使用json格式,方便易用。于是用了json_encode,但是发现居然报语法错误,查了手册才发现,json_enode 是在5.2.0才作为标准扩展加入php的,而我们的机器上php的版本是5.1.6,原来该扩展还未加进来。由于这个应用比较小,而且本人赖得升级php的版本,而且再手工安装这个扩展也比较麻烦,所以想到了使用php实现json_encode,原理上应该不难,找到一段代码,共享之~

代码如下:

<?php
function __json_encode( $data ) {           
    if( is_array($data) || is_object($data) ) {
        $islist = is_array($data) && ( empty($data) || array_keys($data) === range(0,count($data)-1) );
 
        if( $islist ) {
            $json = '[' . implode(',', array_map('__json_encode', $data) ) . ']';
        } else {
            $items = Array();
            foreach( $data as $key => $value ) {
                $items[] = __json_encode("$key") . ':' . __json_encode($value);
            }
            $json = '{' . implode(',', $items) . '}';
        }
    } elseif( is_string($data) ) {
        # Escape non-printable or Non-ASCII characters.
        # I also put the \\ character first, as suggested in comments on the 'addclashes' page.
        $string = '"' . addcslashes($data, "\\\"\n\r\t/" . chr(8) . chr(12)) . '"';
        $json    = '';
        $len    = strlen($string);
        # Convert UTF-8 to Hexadecimal Codepoints.
        for( $i = 0; $i < $len; $i++ ) {
 
            $char = $string[$i];
            $c1 = ord($char);
 
            # Single byte;
            if( $c1 <128 ) {
                $json .= ($c1 > 31) ? $char : sprintf("\\u%04x", $c1);
                continue;
            }
 
            # Double byte
            $c2 = ord($string[++$i]);
            if ( ($c1 & 32) === 0 ) {
                $json .= sprintf("\\u%04x", ($c1 - 192) * 64 + $c2 - 128);
                continue;
            }
 
            # Triple
            $c3 = ord($string[++$i]);
            if( ($c1 & 16) === 0 ) {
                $json .= sprintf("\\u%04x", (($c1 - 224) <<12) + (($c2 - 128) << 6) + ($c3 - 128));
                continue;
            }
 
            # Quadruple
            $c4 = ord($string[++$i]);
            if( ($c1 & 8 ) === 0 ) {
                $u = (($c1 & 15) << 2) + (($c2>>4) & 3) - 1;
 
                $w1 = (54<<10) + ($u<<6) + (($c2 & 15) << 2) + (($c3>>4) & 3);
                $w2 = (55<<10) + (($c3 & 15)<<6) + ($c4-128);
                $json .= sprintf("\\u%04x\\u%04x", $w1, $w2);
            }
        }
    } else {
        # int, floats, bools, null
        $json = strtolower(var_export( $data, true ));
    }
    return $json;
}
?>
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