forked from vitalif/fast-json-stream
421 lines
12 KiB
PHP
421 lines
12 KiB
PHP
<?php
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// Fast streaming JSON parser for PHP
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// Author: Vitaliy Filippov, 2018+
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// License: GNU LGPL 3.0 or MPL (file-level copyleft)
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class JSONStreamException extends Exception {}
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class JSONStream
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{
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const OBJ = 1;
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const ARR = 2;
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protected static $esc = [
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'"' => '"',
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"\\" => "\\",
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'/' => '/',
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'b' => "\b",
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'f' => "\f",
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'n' => "\n",
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'r' => "\r",
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't' => "\t",
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];
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protected $buffer = '';
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protected $totalOffset = 0;
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protected $offset = 0;
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protected $in = []; // [ [ 0 => extern or eof, 1 => type, 2 => value, 3 => current hash key ] ]
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protected $read;
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public function __construct($read)
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{
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$this->read = $read;
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}
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public function enterObject()
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{
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$this->skipWhitespace();
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if ($this->buffer === '')
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{
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throw new JSONStreamException('unexpected end of stream at offset '.($this->totalOffset + $this->offset));
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}
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if (($c = $this->buffer[$this->offset]) !== '{')
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{
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throw new JSONStreamException('unexpected token at offset '.($this->totalOffset + $this->offset).': '.$c);
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}
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$this->offset++;
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$this->skipWhitespace();
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$st = $this->buffer[$this->offset] === '}' ? 2 : 1;
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$this->in[] = [ $st, self::OBJ, NULL, false ];
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}
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public function enterArray()
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{
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$this->skipWhitespace();
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if ($this->buffer === '')
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{
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throw new JSONStreamException('unexpected end of stream at offset '.($this->totalOffset + $this->offset));
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}
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if (($c = $this->buffer[$this->offset]) !== '[')
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{
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throw new JSONStreamException('unexpected token at offset '.($this->totalOffset + $this->offset).': '.$c);
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}
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$this->offset++;
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$this->skipWhitespace();
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$st = $this->buffer[$this->offset] === ']' ? 2 : 1;
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$this->in[] = [ $st, self::ARR, NULL, false ];
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}
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public function exitObject()
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{
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if (!$this->isEnded())
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{
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throw new JSONStreamException('object not ended yet');
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}
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if ($this->in[count($this->in)-1][1] != self::OBJ)
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{
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throw new JSONStreamException('not inside object');
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}
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array_pop($this->in);
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if ($this->in)
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{
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$this->pushValue($v);
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}
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}
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public function exitArray()
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{
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if (!$this->isEnded())
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{
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throw new JSONStreamException('array not ended yet');
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}
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if ($this->in[count($this->in)-1][1] != self::ARR)
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{
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throw new JSONStreamException('not inside array');
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}
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array_pop($this->in);
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if ($this->in)
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{
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$this->pushValue($v);
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}
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}
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public function isEnded()
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{
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return !$this->in || $this->in[count($this->in)-1][0] == 2;
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}
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public function readValue(&$value)
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{
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if ($this->isEnded())
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{
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// Refuse to read anything until exitObject() / exitArray()
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return false;
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}
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$n = count($this->in);
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do
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{
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$v = $this->readToken();
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} while (count($this->in) > $n);
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$value = $v;
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return ($this->in[count($this->in)-1][0] == 1);
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}
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public function unreadBuffer()
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{
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$this->totalOffset += strlen($this->buffer);
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$s = $this->buffer;
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$this->buffer = '';
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$this->offset = 0;
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return $s;
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}
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public function restart()
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{
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$this->totalOffset = 0;
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$this->buffer = '';
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$this->offset = 0;
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$this->in = [];
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}
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protected function read()
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{
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$r = $this->read;
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return $r();
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}
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protected function skipWhitespace()
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{
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while (true)
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{
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if ($this->offset == strlen($this->buffer))
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{
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$this->totalOffset += strlen($this->buffer);
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$this->buffer = $this->read();
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$this->offset = 0;
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}
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$c = $this->buffer[$this->offset];
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if (ctype_space($c))
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{
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$m = NULL;
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preg_match('/\s+/sA', $this->buffer, $m, 0, $this->offset);
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if (!$m)
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{
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return;
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}
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$this->offset += strlen($m[0]);
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}
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else
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{
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return;
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}
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}
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}
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protected function readToken()
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{
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$this->skipWhitespace();
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if ($this->buffer === '')
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{
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throw new JSONStreamException('unexpected end of stream at offset '.($this->totalOffset + $this->offset));
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}
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$c = $this->buffer[$this->offset];
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if ($c === '[')
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{
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$this->offset++;
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$this->skipWhitespace();
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if ($this->buffer[$this->offset] === ']')
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{
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$this->offset++;
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$v = [];
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}
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else
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{
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$this->in[] = [ 0, self::ARR, [], NULL ];
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return NULL;
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}
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}
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elseif ($c === '{')
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{
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$this->offset++;
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$this->skipWhitespace();
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if ($this->buffer[$this->offset] === '}')
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{
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$this->offset++;
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$v = [];
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}
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else
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{
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$this->in[] = [ 0, self::OBJ, [], NULL ];
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return NULL;
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}
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}
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elseif ($c === '"')
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{
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$this->offset++;
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$v = '';
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if ($this->offset >= strlen($this->buffer)-6)
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{
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$this->buffer .= $this->read();
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}
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while (preg_match('/(?:[^"\\\\]+|\\\\[\\\\"\/bfnrt]|(?:\\\\u[0-9a-fA-F]{4})+)/As', $this->buffer, $m, 0, $this->offset))
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{
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$this->offset += strlen($m[0]);
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if ($m[0][0] == "\\")
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{
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if ($m[0] == 'u')
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$v .= mb_convert_encoding(pack('H*', str_replace('\\u', '', $m[0])), 'UTF-8', 'UTF-16BE');
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else
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{
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$v .= self::$esc[$m[0][1]];
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}
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}
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else
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{
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$v .= $m[0];
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}
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if ($this->offset >= strlen($this->buffer)-6)
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{
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$this->buffer .= $this->read();
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}
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}
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if (($m = substr($this->buffer, $this->offset, 1)) != '"')
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{
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if ($m)
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throw new JSONStreamException('unexpected token at offset '.($this->totalOffset + $this->offset).': '.$m);
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else
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throw new JSONStreamException('unexpected end of stream at offset '.($this->totalOffset + $this->offset));
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}
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else
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{
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$this->offset++;
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}
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}
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elseif ($c === 't')
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{
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if ($this->offset >= strlen($this->buffer)-5)
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{
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$this->buffer .= $this->read();
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}
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if (substr($this->buffer, $this->offset, 4) !== 'true')
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{
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throw new JSONStreamException('unexpected token at offset '.($this->totalOffset + $this->offset).': '.$c);
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}
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$this->offset += 4;
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$v = true;
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}
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elseif ($c === 'f')
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{
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if ($this->offset >= strlen($this->buffer)-6)
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{
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$this->buffer .= $this->read();
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}
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if (substr($this->buffer, $this->offset, 5) !== 'false')
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{
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throw new JSONStreamException('unexpected token at offset '.($this->totalOffset + $this->offset).': '.$c);
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}
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$this->offset += 5;
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$v = false;
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}
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elseif ($c === 'n')
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{
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if ($this->offset >= strlen($this->buffer)-5)
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{
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$this->buffer .= $this->read();
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}
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if (substr($this->buffer, $this->offset, 4) !== 'null')
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{
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throw new JSONStreamException('unexpected token at offset '.($this->totalOffset + $this->offset).': '.$c);
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}
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$this->offset += 4;
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$v = NULL;
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}
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elseif (ctype_digit($c) || $c == '-')
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{
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if ($this->offset >= strlen($this->buffer)-64)
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{
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$this->buffer .= $this->read();
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}
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if (!preg_match('/-?(?:\d+)(?:\.\d+)?(?:[Ee][\+\-]?\d+)?/As', $this->buffer, $m, 0, $this->offset))
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{
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throw new JSONStreamException('unexpected token at offset '.($this->totalOffset + $this->offset).': '.$c);
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}
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$this->offset += strlen($m[0]);
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$v = 0+$m[0];
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}
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else
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{
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throw new JSONStreamException('unexpected token at offset '.($this->totalOffset + $this->offset).': '.$c);
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}
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$this->pushValue($v);
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return $v;
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}
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protected function pushValue(&$v)
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{
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redo:
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$last = &$this->in[count($this->in)-1];
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if ($last[1] == self::ARR)
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{
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if (!$last[0])
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{
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$last[2][] = $v;
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}
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$this->skipWhitespace();
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if ($this->buffer[$this->offset] == ',')
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{
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$this->offset++;
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}
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$this->skipWhitespace();
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if ($this->buffer[$this->offset] == ']')
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{
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$this->offset++;
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if ($last[0] == 0)
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{
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$v = $last[2];
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array_pop($this->in);
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if ($this->in)
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{
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goto redo;
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}
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}
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else
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{
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$last[0] = 2; // end of value, caller must call exitObject / exitArray
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}
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}
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}
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elseif ($last[1] == self::OBJ)
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{
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if (!$last[3])
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{
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if (!is_string($v))
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{
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if (is_array($v))
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{
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throw new JSONStreamException('object key must be a string, but it is '.json_encode($v, JSON_UNESCAPED_UNICODE|JSON_UNESCAPED_SLASHES));
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}
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elseif ($v === true)
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{
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$v = 'true';
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}
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elseif ($v === false)
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{
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$v = 'false';
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}
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elseif ($v === NULL)
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{
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$v = 'null';
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}
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}
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if ($last[0])
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{
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$last[3] = true;
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}
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else
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{
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$last[3] = $v;
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}
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$this->skipWhitespace();
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if (($c = $this->buffer[$this->offset]) != ':')
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{
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throw new JSONStreamException('unexpected token at offset '.($this->totalOffset + $this->offset).': '.$c);
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}
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$this->offset++;
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}
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else
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{
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if (!$last[0])
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{
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$last[2][$last[3]] = $v;
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}
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$last[3] = NULL;
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$this->skipWhitespace();
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if ($this->buffer[$this->offset] == ',')
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{
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$this->offset++;
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}
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$this->skipWhitespace();
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if ($this->buffer[$this->offset] == '}')
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{
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$this->offset++;
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if ($last[0] == 0)
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{
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$v = $last[2];
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array_pop($this->in);
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if ($this->in)
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{
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goto redo;
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}
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}
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else
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{
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$last[0] = 2; // end of value, caller must call exitObject / exitArray
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}
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}
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}
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}
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}
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}
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