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<?php declare(strict_types=1); |
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/** |
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* portable-game-notation (https://github.com/chesszebra/portable-game-notation) |
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* |
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* @link https://github.com/chesszebra/portable-game-notation for the canonical source repository |
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* @copyright Copyright (c) 2017 Chess Zebra (https://chesszebra.com) |
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* @license https://github.com/chesszebra/portable-game-notation/blob/master/LICENSE.md MIT |
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*/ |
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namespace ChessZebra\PortableGameNotation\Lexer; |
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use ChessZebra\PortableGameNotation\Token\TokenInterface; |
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use ChessZebra\PortableGameNotation\Lexer\Exception\InvalidTokenException; |
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use InvalidArgumentException; |
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/** |
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* Reads PGN games from a stream. |
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*/ |
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final class StreamLexer extends AbstractLexer |
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{ |
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/** |
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* @var resource |
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*/ |
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private $stream; |
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/** |
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* Initializes a new instance of this class. |
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* |
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* @param resource $stream The stream to read from. |
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* @throws InvalidArgumentException Thrown when the stream is invalid. |
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*/ |
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public function __construct($stream) |
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{ |
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parent::__construct(); |
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if (!is_resource($stream)) { |
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throw new InvalidArgumentException('Invalid stream provided.'); |
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} |
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$this->stream = $stream; |
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} |
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public function getOffset() |
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{ |
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$position = ftell($this->stream); |
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if ($this->buffer) { |
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$position -= strlen($this->buffer); |
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} |
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return $position; |
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} |
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/** |
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* Gets the next token from the lexer. |
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* |
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* @return TokenInterface|null |
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* @throws InvalidTokenException |
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*/ |
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public function getNextToken(): ?TokenInterface |
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{ |
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if (feof($this->stream)) { |
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return null; |
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} |
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// Make sure the buffer is always filled. |
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if (!$this->buffer || strlen($this->buffer) < 4096) { |
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$this->buffer .= fread($this->stream, 4096); |
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} |
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return parent::getNextToken(); |
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} |
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/** |
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* Peeks in the stream what the next token will be. |
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* |
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* @return TokenInterface|null |
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* @throws InvalidTokenException |
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*/ |
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public function peekNextToken(): ?TokenInterface |
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{ |
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$offset = ftell($this->stream); |
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$buffer = $this->buffer; |
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$token = $this->getNextToken(); |
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fseek($this->stream, $offset); |
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$this->buffer = $buffer; |
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return $token; |
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} |
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} |
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chesszebra /
portable-game-notation
