ecshop类的解析2 json_encode和json_decode的具体实现

在看ecshop源码时，看到json这个类，研究了一下，它是为了兼容低版本php而做出的类，是对php的数据和json转换时使用的。

encode和decode函数是对json的操作，对应json_encode和json_decode函数。

<?php

/**
* ECSHOP JSON

* $Author: liubo $
* $Id: cls_json.php 17217 2011-01-19 06:29:08Z liubo $
*/

class JSON
{
var $at = 0;
var $ch = '';
var $text = '';

function encode($arg, $force = true)
{
static $_force;
if (is_null($_force))
{
$_force = $force;
}

if ($_force && EC_CHARSET == 'utf-8' && function_exists('json_encode'))
{
return json_encode($arg);
}

$returnValue = '';
$c = '';
$i = '';
$l = '';
$s = '';
$v = '';
$numeric = true;

switch (gettype($arg))
{
case 'array':
foreach ($arg AS $i => $v)
{
if (!is_numeric($i))
{
$numeric = false;
break;
}
}

if ($numeric)
{
foreach ($arg AS $i => $v)
{
if (strlen($s) > 0)
{
$s .= ',';
}
$s .= $this->encode($arg[$i]);
}

$returnValue = '[' . $s . ']';
}
else
{
foreach ($arg AS $i => $v)
{
if (strlen($s) > 0)
{
$s .= ',';
}
$s .= $this->encode($i) . ':' . $this->encode($arg[$i]);
}

$returnValue = '{' . $s . '}';
}
break;

case 'object':
foreach (get_object_vars($arg) AS $i => $v)
{
$v = $this->encode($v);

if (strlen($s) > 0)
{
$s .= ',';
}
$s .= $this->encode($i) . ':' . $v;
}

$returnValue = '{' . $s . '}';
break;

case 'integer':
case 'double':
$returnValue = is_numeric($arg) ? (string) $arg : 'null';
break;

case 'string':
$returnValue = '"' . strtr($arg, array(
"\r" => '\\r', "\n" => '\\n', "\t" => '\\t', "\b" => '\\b',
"\f" => '\\f', '\\' => '\\\\', '"' => '\"',
"\x00" => '\u0000', "\x01" => '\u0001', "\x02" => '\u0002', "\x03" => '\u0003',
"\x04" => '\u0004', "\x05" => '\u0005', "\x06" => '\u0006', "\x07" => '\u0007',
"\x08" => '\b', "\x0b" => '\u000b', "\x0c" => '\f', "\x0e" => '\u000e',
"\x0f" => '\u000f', "\x10" => '\u0010', "\x11" => '\u0011', "\x12" => '\u0012',
"\x13" => '\u0013', "\x14" => '\u0014', "\x15" => '\u0015', "\x16" => '\u0016',
"\x17" => '\u0017', "\x18" => '\u0018', "\x19" => '\u0019', "\x1a" => '\u001a',
"\x1b" => '\u001b', "\x1c" => '\u001c', "\x1d" => '\u001d', "\x1e" => '\u001e',
"\x1f" => '\u001f'
)) . '"';
break;

case 'boolean':
$returnValue = $arg?'true':'false';
break;

default:
$returnValue = 'null';
}

return $returnValue;
}

function decode($text,$type=0) // 榛樿?type=0杩斿洖obj,type=1杩斿洖array
{
if (empty($text))
{
return '';
}
elseif (!is_string($text))
{
return false;
}

if (EC_CHARSET === 'utf-8' && function_exists('json_decode'))
{
return addslashes_deep_obj(json_decode(stripslashes($text),$type));
}

$this->at = 0;
$this->ch = '';
$this->text = strtr(stripslashes($text), array(
"\r" => '', "\n" => '', "\t" => '', "\b" => '',
"\x00" => '', "\x01" => '', "\x02" => '', "\x03" => '',
"\x04" => '', "\x05" => '', "\x06" => '', "\x07" => '',
"\x08" => '', "\x0b" => '', "\x0c" => '', "\x0e" => '',
"\x0f" => '', "\x10" => '', "\x11" => '', "\x12" => '',
"\x13" => '', "\x14" => '', "\x15" => '', "\x16" => '',
"\x17" => '', "\x18" => '', "\x19" => '', "\x1a" => '',
"\x1b" => '', "\x1c" => '', "\x1d" => '', "\x1e" => '',
"\x1f" => ''
));

$this->next();
$return = $this->val();

$result = empty($type) ? $return : $this->object_to_array($return);

return addslashes_deep_obj($result);
}

/**
* triggers a PHP_ERROR
*
* @access private
* @param string $m error message
*
* @return void
*/
function error($m)
{
echo($m . ' at offset ' . $this->at . ': ' . $this->text);
}

/**
* returns the next character of a JSON string
*
* @access private
*
* @return string
*/
function next()
{
$this->ch = !isset($this->text{$this->at}) ? '' : $this->text{$this->at};
$this->at++;

return $this->ch;
}

/**
* handles strings
*
* @access private
*
* @return void
*/
function str()
{
$i = '';
$s = '';
$t = '';
$u = '';

if ($this->ch == '"')
{
while ($this->next() !== null)
{
if ($this->ch == '"')
{
$this->next();

return $s;
}
elseif ($this->ch == '\\')
{
switch ($this->next())
{
case 'b':
$s .= '\b';
break;

case 'f':
$s .= '\f';
break;

case 'n':
$s .= '\n';
break;

case 'r':
$s .= '\r';
break;

case 't':
$s .= '\t';
break;

case 'u':
$u = 0;

for ($i = 0; $i < 4; $i++)
{
$t = (integer) sprintf('%01c', hexdec($this->next()));

if (!is_numeric($t))
{
break 2;
}
$u = $u * 16 + $t;
}

$s .= chr($u);
break;
case '\'':
$s .= '\'';
break;
default:
$s .= $this->ch;
}
}
else
{
$s .= $this->ch;
}
}
}

$this->error('Bad string');
}

/**
* handless arrays
*
* @access private
*
* @return void
*/
function arr()
{
$a = array();

if ($this->ch == '[')
{
$this->next();

if ($this->ch == ']')
{
$this->next();

return $a;
}

while (isset($this->ch))
{
array_push($a, $this->val());

if ($this->ch == ']')
{
$this->next();

return $a;

}
elseif ($this->ch != ',')
{
break;
}

$this->next();

}

$this->error('Bad array');
}
}

/**
* handles objects
*
* @access public
*
* @return void
*/
function obj()
{
$k = '';
$o = new StdClass();

if ($this->ch == '{')
{
$this->next();

if ($this->ch == '}')
{
$this->next();

return $o;
}

while ($this->ch)
{
$k = $this->str();

if ($this->ch != ':')
{
break;
}

$this->next();
$o->$k = $this->val();

if ($this->ch == '}')
{
$this->next();

return $o;
}
elseif ($this->ch != ',')
{
break;
}

$this->next();
}
}

$this->error('Bad object');
}

/**
* handles objects
*
* @access public
*
* @return void
*/
function assoc()
{
$k = '';
$a = array();

if ($this->ch == '<')
{
$this->next();

if ($this->ch == '>')
{
$this->next();

return $a;
}

while ($this->ch)
{
$k = $this->str();

if ($this->ch != ':')
{
break;
}

$this->next();
$a[$k] = $this->val();

if ($this->ch == '>')
{
$this->next();

return $a;
}
elseif ($this->ch != ',')
{
break;
}

$this->next();
}
}

$this->error('Bad associative array');
}

/**
* handles numbers
*
* @access private
*
* @return void
*/
function num()
{
$n = '';
$v = '';

if ($this->ch == '-')
{
$n = '-';
$this->next();
}

while ($this->ch >= '0' && $this->ch <= '9')
{
$n .= $this->ch;
$this->next();
}

if ($this->ch == '.')
{
$n .= '.';

while ($this->next() && $this->ch >= '0' && $this->ch <= '9')
{
$n .= $this->ch;
}
}

if ($this->ch == 'e' || $this->ch == 'E')
{
$n .= 'e';
$this->next();

if ($this->ch == '-' || $this->ch == '+')
{
$n .= $this->ch;
$this->next();
}

while ($this->ch >= '0' && $this->ch <= '9')
{
$n .= $this->ch;
$this->next();
}
}

$v += $n;

if (!is_numeric($v))
{
$this->error('Bad number');
}
else
{
return $v;
}
}

/**
* handles words
*
* @access private
*
* @return mixed
*/
function word()
{
switch ($this->ch)
{
case 't':

if ($this->next() == 'r' && $this->next() == 'u' && $this->next() == 'e')
{
$this->next();

return true;
}
break;

case 'f':
if ($this->next() == 'a' && $this->next() == 'l' && $this->next() == 's' && $this->next() == 'e')
{
$this->next();

return false;
}
break;

case 'n':
if ($this->next() == 'u' && $this->next() == 'l' && $this->next() == 'l')
{
$this->next();

return null;
}
break;
}

$this->error('Syntax error');
}

/**
* generic value handler
*
* @access private
*
* @return mixed
*/
function val()
{
switch ($this->ch)
{
case '{':
return $this->obj();

case '[':
return $this->arr();

case '<':
return $this->assoc();

case '"':
return $this->str();

case '-':
return $this->num();

default:
return ($this->ch >= '0' && $this->ch <= '9') ? $this->num() : $this->word();
}
}

/**
* Gets the properties of the given object recursion
*
* @access private
*
* @return array
*/
function object_to_array($obj)
{
$_arr = is_object($obj) ? get_object_vars($obj) : $obj;
foreach ($_arr as $key => $val)
{
$val = (is_array($val) || is_object($val)) ? $this->object_to_array($val) : $val;
$arr[$key] = $val;
}
return $arr;
}
}

?>