<?php

/**
* This file is part of FPDI
*
* @package setasign\Fpdi
* @copyright Copyright (c) 2024 Setasign GmbH & Co. KG (https://www.setasign.com)
* @license http://opensource.org/licenses/mit-license The MIT License
*/

namespace setasign\Fpdi\PdfParser;

/**
* A tokenizer class.
*/
class Tokenizer
{
/**
* @var StreamReader
*/
protected $streamReader;

/**
* A token stack.
*
* @var string[]
*/
protected $stack = [];

/**
* Tokenizer constructor.
*
* @param StreamReader $streamReader
*/
public function __construct(StreamReader $streamReader)
{
$this->streamReader = $streamReader;
}

/**
* Get the stream reader instance.
*
* @return StreamReader
*/
public function getStreamReader()
{
return $this->streamReader;
}

/**
* Clear the token stack.
*/
public function clearStack()
{
$this->stack = [];
}

/**
* Push a token onto the stack.
*
* @param string $token
*/
public function pushStack($token)
{
$this->stack[] = $token;
}

/**
* Get next token.
*
* @return false|string
*/
public function getNextToken()
{
$token = \array_pop($this->stack);
if ($token !== null) {
return $token;
}

if (($byte = $this->streamReader->readByte()) === false) {
return false;
}

if (\in_array($byte, ["\x20", "\x0A", "\x0D", "\x0C", "\x09", "\x00"], true)) {
if ($this->leapWhiteSpaces() === false) {
return false;
}
$byte = $this->streamReader->readByte();
}

switch ($byte) {
case '/':
case '[':
case ']':
case '(':
case ')':
case '{':
case '}':
case '<':
case '>':
return $byte;
case '%':
$this->streamReader->readLine();
return $this->getNextToken();
}

/* This way is faster than checking single bytes.
*/
$bufferOffset = $this->streamReader->getOffset();
do {
$lastBuffer = $this->streamReader->getBuffer(false);
$pos = \strcspn(
$lastBuffer,
"\x00\x09\x0A\x0C\x0D\x20()<>[]{}/%",
$bufferOffset
);
} while (
// Break the loop if a delimiter or white space char is matched
// in the current buffer or increase the buffers length
$bufferOffset + $pos === \strlen($lastBuffer)
&& $this->streamReader->increaseLength()
);

$result = \substr($lastBuffer, $bufferOffset - 1, $pos + 1);
$this->streamReader->setOffset($bufferOffset + $pos);

return $result;
}

/**
* Leap white spaces.
*
* @return boolean
*/
public function leapWhiteSpaces()
{
do {
if (!$this->streamReader->ensureContent()) {
return false;
}

$buffer = $this->streamReader->getBuffer(false);
$matches = \strspn($buffer, "\x20\x0A\x0C\x0D\x09\x00", $this->streamReader->getOffset());
if ($matches > 0) {
$this->streamReader->addOffset($matches);
}
} while ($this->streamReader->getOffset() >= $this->streamReader->getBufferLength());

return true;
}
}