Passed
Push — master ( ea9949...4750e8 )
by Christoffer
02:23
created

Lexer::lookahead()   A

Complexity

Conditions 3
Paths 2

Size

Total Lines 13
Code Lines 8

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
dl 0
loc 13
rs 9.4285
c 0
b 0
f 0
cc 3
eloc 8
nc 2
nop 0
1
<?php
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namespace Digia\GraphQL\Language;
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use Digia\GraphQL\Error\GraphQLError;
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use Digia\GraphQL\Error\SyntaxError;
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use Digia\GraphQL\Language\Reader\ReaderInterface;
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class Lexer implements LexerInterface
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{
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    /**
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     * @var Source|null
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     */
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    protected $source;
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    /**
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     * @var array
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     */
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    protected $options = [];
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    /**
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     * @var array|ReaderInterface[]
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     */
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    protected $readers;
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    /**
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     * The previously focused non-ignored token.
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     *
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     * @var Token
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     */
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    protected $lastToken;
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    /**
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     * The currently focused non-ignored token.
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     *
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     * @var Token
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     */
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    protected $token;
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    /**
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     * The (1-indexed) line containing the current token.
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     *
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     * @var int
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     */
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    protected $line;
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    /**
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     * The character offset at which the current line begins.
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     *
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     * @var int
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     */
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    protected $lineStart;
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    /**
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     * Lexer constructor.
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     *
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     * @param ReaderInterface[] $readers
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     */
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    public function __construct(array $readers)
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    {
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        $startOfFileToken = new Token(TokenKindEnum::SOF);
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        foreach ($readers as $reader) {
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            $reader->setLexer($this);
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        }
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        $this->readers   = $readers;
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        $this->lastToken = $startOfFileToken;
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        $this->token     = $startOfFileToken;
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        $this->line      = 1;
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        $this->lineStart = 0;
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    }
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    /**
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     * @inheritdoc
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     */
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    public function advance(): Token
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    {
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        $this->lastToken = $this->token;
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        return $this->token = $this->lookahead();
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    }
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    /**
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     * @inheritdoc
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     */
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    public function lookahead(): Token
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    {
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        $token = $this->token;
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        if (TokenKindEnum::EOF !== $token->getKind()) {
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            do {
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                $next = $this->readToken($token);
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                $token->setNext($next);
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                $token = $next;
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            } while (TokenKindEnum::COMMENT === $token->getKind());
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        }
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        return $token;
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    }
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    /**
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     * @inheritdoc
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     */
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    public function getBody(): string
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    {
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        return $this->getSource()->getBody();
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    }
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    /**
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     * @inheritdoc
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     */
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    public function getTokenKind(): string
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    {
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        return $this->token->getKind();
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    }
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    /**
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     * @inheritdoc
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     */
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    public function getTokenValue(): ?string
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    {
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        return $this->token->getValue();
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    }
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    /**
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     * @inheritdoc
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     */
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    public function getToken(): Token
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    {
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        return $this->token;
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    }
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    /**
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     * @inheritdoc
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     */
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    public function getSource(): Source
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    {
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        if ($this->source instanceof Source) {
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            return $this->source;
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        }
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        throw new \Exception('No source has been set.');
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    }
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    /**
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     * @inheritdoc
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     */
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    public function getLastToken(): Token
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    {
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        return $this->lastToken;
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    }
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    /**
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     * @param Source $source
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     * @return Lexer
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     */
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    public function setSource(Source $source)
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    {
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        $this->source = $source;
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        return $this;
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    }
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    /**
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     * @param array $options
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     * @return
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     */
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    public function setOptions(array $options)
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    {
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        $this->options = $options;
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        return $this;
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    }
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    /**
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     * @param int   $code
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     * @param int   $pos
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     * @param int   $line
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     * @param int   $col
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     * @param Token $prev
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     * @return Token
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     * @throws SyntaxError
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     */
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    public function read(int $code, int $pos, int $line, int $col, Token $prev): Token
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    {
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        if (($reader = $this->getReader($code, $pos)) !== null) {
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            return $reader->read($code, $pos, $line, $col, $prev);
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        }
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        throw new SyntaxError($this->unexpectedCharacterMessage($code));
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    }
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    /**
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     * @param Token $prev
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     * @return Token
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     * @throws GraphQLError
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     */
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    protected function readToken(Token $prev): Token
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    {
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        $body       = $this->source->getBody();
0 ignored issues
show
Bug introduced by
The method getBody() does not exist on null. ( Ignorable by Annotation )

If this is a false-positive, you can also ignore this issue in your code via the ignore-call  annotation

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        /** @scrutinizer ignore-call */ 
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        $body       = $this->source->getBody();

This check looks for calls to methods that do not seem to exist on a given type. It looks for the method on the type itself as well as in inherited classes or implemented interfaces.

This is most likely a typographical error or the method has been renamed.

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        $bodyLength = mb_strlen($body);
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        $pos  = $this->positionAfterWhitespace($body, $prev->getEnd());
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        $line = $this->line;
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        $col  = 1 + $pos - $this->lineStart;
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        if ($pos >= $bodyLength) {
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            return new Token(TokenKindEnum::EOF, $bodyLength, $bodyLength, $line, $col, $prev);
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        }
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        $code = charCodeAt($body, $pos);
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        if (isSourceCharacter($code)) {
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            throw new SyntaxError(sprintf('Cannot contain the invalid character %s', printCharCode($code)));
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        }
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        return $this->read($code, $pos, $line, $col, $prev);
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    }
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    /**
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     * @param int $code
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     * @return string
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     */
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    protected function unexpectedCharacterMessage(int $code): string
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    {
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        if ($code === 39) {
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            // '
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            return 'Unexpected single quote character (\'), did you mean to use a double quote (")?';
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        }
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        return sprintf('Cannot parse the unexpected character %s', printCharCode($code));
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    }
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    /**
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     * @param int $code
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     * @param int $pos
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     * @return ReaderInterface|null
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     */
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    protected function getReader(int $code, int $pos): ?ReaderInterface
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    {
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        foreach ($this->readers as $reader) {
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            if ($reader instanceof ReaderInterface && $reader->supportsReader($code, $pos)) {
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                return $reader;
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            }
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        }
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        return null;
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    }
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    /**
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     * @param string $body
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     * @param int    $startPosition
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     * @return int
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     */
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    protected function positionAfterWhitespace(string $body, int $startPosition): int
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    {
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        $bodyLength = mb_strlen($body);
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        $pos        = $startPosition;
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        while ($pos < $bodyLength) {
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            $code = charCodeAt($body, $pos);
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            if ($code === 9 || $code === 32 || $code === 44 || $code === 0xfeff) {
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                // tab | space | comma | BOM
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                ++$pos;
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            } elseif ($code === 10) {
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                // new line
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                ++$pos;
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                $this->advanceLine($pos);
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            } elseif ($code === 13) {
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                // carriage return
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                if (charCodeAt($body, $pos + 1) === 10) {
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                    $pos += 2;
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                } else {
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                    ++$pos;
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                }
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                $this->advanceLine($pos);
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            } else {
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                break;
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            }
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        }
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        return $pos;
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    }
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    /**
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     * @param int $pos
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     */
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    protected function advanceLine(int $pos)
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    {
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        ++$this->line;
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        $this->lineStart = $pos;
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    }
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}
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