json_encode and json_decode
<?php/** * PHP4 JSON Encode 函数 **/ echo jsonEncode($_SERVER)==json_encode($_SERVER);echo jsonEncode(jsonDecode(json_encode($_SERVER)))==json_encode($_SERVER);echo print_r(jsonDecode(jsonEncode($_ENV)),true)==print_r($_ENV,true);/************************************************************用了很多callback,本来想用create_function(lambda style)的,但那种方式内存占用过大而且最别扭的是PHP 函数里的static变量不能设为函数返回值,而且函数(包括lambda)始终是全局访问权限,不能以类似closure的方式读取嵌套在外层的函数里的变量的值最好只好多声明几个全局函数了针对PHP4的json_encode与json_decode实现,官方有一个pear包 Services_JSON特地两者进行对比:jsonEncode函数执行速度是 Services_JSON->encode的3倍jsonDecode函数执行速度是 Services_JSON->decode的6倍唯一不足的是jsonEncode函数内存占用要超过Services_JSON->encode而jsonDecode内存占用则要比 Services_JSON->decode少得多(少了一位数)jsonDecode函数支持无限层嵌套的数组(只要机器吃得消就行)主要得益于使用了eval,而且速度也快了许多可以在PHP5使用下面的方式测试,几乎与内置的函数输出结果一样echo jsonEncode($_SERVER)==json_encode($_SERVER);echo jsonEncode(jsonDecode(json_encode($_SERVER)))==json_encode($_SERVER);echo print_r(jsonDecode(jsonEncode($_SERVER)),true)==print_r($_SERVER,true);不同的一点是PHP5中json_decode返回一个stdClass,而这里的jsonDecode返回的是数组*************************************************************/function jsonEncode($data) {if (2==func_num_args()) {$callee=__FUNCTION__;return json_format_scalar(strval(func_get_arg(1))).":".$callee($data);}is_object($data) && $data=get_object_vars($data);if (is_scalar($data)) { return json_format_scalar($data); }if (empty($data)) { return '[]';}$keys=array_keys($data);if (is_numeric(join('',$keys))) {$data=array_map(__FUNCTION__,$data);return '['.join(',',$data).']';} else {$data=array_map(__FUNCTION__,array_values($data),$keys);return '{'.join(',',$data).'}';}}function json_format_scalar($value) {if (is_bool($value)) {$value = $value?'true':'false';} else if (is_int($value)) {$value = (int)$value;} else if (is_float($value)) {$value = (float)$value;} else if (is_string($value)) {$value=addcslashes($value,"\n\r\"\/\\");$value='"'.preg_replace_callback('|[^\x00-\x7F]+|','json_utf_slash_callback',$value).'"';} else {$value='null';}return $value;}function json_utf_slash_callback($data) {if (is_array($data)) {$chars=str_split(iconv("UTF-8","UCS-2",$data),2);$chars=array_map(__FUNCTION__,$chars);return join("",$chars);} else {$char1=dechex(ord($data{0}));$char2=dechex(ord($data{1}));return sprintf("\u%02s%02s",$char1,$char2);}}function json_utf_slash_strip($data) {if (is_array($data)) {return $data.iconv("UCS-2","UTF-8",chr(hexdec($data)).chr(hexdec($data)));} else {return preg_replace_callback('/(?<!\\\\)((?:\\\\\\\\)*)\\\\u({2})({2})/i',__FUNCTION__,$data);}}function jsonDecode($data) {static $strings,$count=0;if (is_string($data)) {$data=trim($data);if ($data{0}!='{' && $data{0}!='[') return json_utf_slash_strip($data);$strings=array();$data=preg_replace_callback('/"([\s\S]*?(?<!\\\\)(?:\\\\\\\\)*)"/',__FUNCTION__,$data);//简单的危险性检测//echo $data;$cleanData=str_ireplace(array('true','false','undefined','null','{','}','[',']',',',':','#'),'',$data);if (!is_numeric($cleanData)) {throw new Exception('Dangerous!The JSONString is dangerous!');return NULL;}$data=str_replace(array('{','[',']','}',':','null'),array('array(','array(',')',')','=>','NULL'),$data);$data=preg_replace_callback('/#\d+/',__FUNCTION__,$data);//抑制错误,诸如{123###}这样错误的JSON是不能转换成PHP数组的@$data=eval("return $data;");$strings=$count=0;return $data;} elseif (count($data)>1) {//存储字符串$strings[]=json_utf_slash_strip(str_replace(array('$','\\/'),array('\\$','/'),$data));return '#'.($count++);} else {//读取存储的值$index=substr($data,1);return $strings[$index];}}
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