Viewing file:  StreamReader.php (11.67 KB) -rw-r--r--
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<?php
/**
* This file is part of FPDI
*
* @package setasign\Fpdi
* @copyright Copyright (c) 2020 Setasign GmbH & Co. KG (https://www.setasign.com)
* @license http://opensource.org/licenses/mit-license The MIT License
*/
namespace setasign\Fpdi\PdfParser;
/**
* A stream reader class
*/
class StreamReader
{
/**
* Creates a stream reader instance by a string value.
*
* @param string $content
* @param int $maxMemory
* @return StreamReader
*/
public static function createByString($content, $maxMemory = 2097152)
{
$h = \fopen('php://temp/maxmemory:' . ((int) $maxMemory), 'r+b');
\fwrite($h, $content);
\rewind($h);
return new self($h, true);
}
/**
* Creates a stream reader instance by a filename.
*
* @param string $filename
* @return StreamReader
*/
public static function createByFile($filename)
{
$h = \fopen($filename, 'rb');
return new self($h, true);
}
/**
* Defines whether the stream should be closed when the stream reader instance is deconstructed or not.
*
* @var bool
*/
protected $closeStream;
/**
* The stream resource.
*
* @var resource
*/
protected $stream;
/**
* The byte-offset position in the stream.
*
* @var int
*/
protected $position;
/**
* The byte-offset position in the buffer.
*
* @var int
*/
protected $offset;
/**
* The buffer length.
*
* @var int
*/
protected $bufferLength;
/**
* The total length of the stream.
*
* @var int
*/
protected $totalLength;
/**
* The buffer.
*
* @var string
*/
protected $buffer;
/**
* StreamReader constructor.
*
* @param resource $stream
* @param bool $closeStream Defines whether to close the stream resource if the instance is destructed or not.
*/
public function __construct($stream, $closeStream = false)
{
if (!\is_resource($stream)) {
throw new \InvalidArgumentException(
'No stream given.'
);
}
$metaData = \stream_get_meta_data($stream);
if (!$metaData['seekable']) {
throw new \InvalidArgumentException(
'Given stream is not seekable!'
);
}
$this->stream = $stream;
$this->closeStream = $closeStream;
$this->reset();
}
/**
* The destructor.
*/
public function __destruct()
{
$this->cleanUp();
}
/**
* Closes the file handle.
*/
public function cleanUp()
{
if ($this->closeStream && is_resource($this->stream)) {
\fclose($this->stream);
}
}
/**
* Returns the byte length of the buffer.
*
* @param bool $atOffset
* @return int
*/
public function getBufferLength($atOffset = false)
{
if ($atOffset === false) {
return $this->bufferLength;
}
return $this->bufferLength - $this->offset;
}
/**
* Get the current position in the stream.
*
* @return int
*/
public function getPosition()
{
return $this->position;
}
/**
* Returns the current buffer.
*
* @param bool $atOffset
* @return string
*/
public function getBuffer($atOffset = true)
{
if ($atOffset === false) {
return $this->buffer;
}
$string = \substr($this->buffer, $this->offset);
return (string) $string;
}
/**
* Gets a byte at a specific position in the buffer.
*
* If the position is invalid the method will return false.
*
* If the $position parameter is set to null the value of $this->offset will be used.
*
* @param int|null $position
* @return string|bool
*/
public function getByte($position = null)
{
$position = (int) ($position !== null ? $position : $this->offset);
if (
$position >= $this->bufferLength
&& (!$this->increaseLength() || $position >= $this->bufferLength)
) {
return false;
}
return $this->buffer[$position];
}
/**
* Returns a byte at a specific position, and set the offset to the next byte position.
*
* If the position is invalid the method will return false.
*
* If the $position parameter is set to null the value of $this->offset will be used.
*
* @param int|null $position
* @return string|bool
*/
public function readByte($position = null)
{
if ($position !== null) {
$position = (int) $position;
// check if needed bytes are available in the current buffer
if (!($position >= $this->position && $position < $this->position + $this->bufferLength)) {
$this->reset($position);
$offset = $this->offset;
} else {
$offset = $position - $this->position;
}
} else {
$offset = $this->offset;
}
if (
$offset >= $this->bufferLength
&& ((!$this->increaseLength()) || $offset >= $this->bufferLength)
) {
return false;
}
$this->offset = $offset + 1;
return $this->buffer[$offset];
}
/**
* Read bytes from the current or a specific offset position and set the internal pointer to the next byte.
*
* If the position is invalid the method will return false.
*
* If the $position parameter is set to null the value of $this->offset will be used.
*
* @param int $length
* @param int|null $position
* @return string|false
*/
public function readBytes($length, $position = null)
{
$length = (int) $length;
if ($position !== null) {
// check if needed bytes are available in the current buffer
if (!($position >= $this->position && $position < $this->position + $this->bufferLength)) {
$this->reset($position, $length);
$offset = $this->offset;
} else {
$offset = $position - $this->position;
}
} else {
$offset = $this->offset;
}
if (
($offset + $length) > $this->bufferLength
&& ((!$this->increaseLength($length)) || ($offset + $length) > $this->bufferLength)
) {
return false;
}
$bytes = \substr($this->buffer, $offset, $length);
$this->offset = $offset + $length;
return $bytes;
}
/**
* Read a line from the current position.
*
* @param int $length
* @return string|bool
*/
public function readLine($length = 1024)
{
if ($this->ensureContent() === false) {
return false;
}
$line = '';
while ($this->ensureContent()) {
$char = $this->readByte();
if ($char === "\n") {
break;
}
if ($char === "\r") {
if ($this->getByte() === "\n") {
$this->addOffset(1);
}
break;
}
$line .= $char;
if (\strlen($line) >= $length) {
break;
}
}
return $line;
}
/**
* Set the offset position in the current buffer.
*
* @param int $offset
*/
public function setOffset($offset)
{
if ($offset > $this->bufferLength || $offset < 0) {
throw new \OutOfRangeException(
\sprintf('Offset (%s) out of range (length: %s)', $offset, $this->bufferLength)
);
}
$this->offset = (int) $offset;
}
/**
* Returns the current offset in the current buffer.
*
* @return int
*/
public function getOffset()
{
return $this->offset;
}
/**
* Add an offset to the current offset.
*
* @param int $offset
*/
public function addOffset($offset)
{
$this->setOffset($this->offset + $offset);
}
/**
* Make sure that there is at least one character beyond the current offset in the buffer.
*
* @return bool
*/
public function ensureContent()
{
while ($this->offset >= $this->bufferLength) {
if (!$this->increaseLength()) {
return false;
}
}
return true;
}
/**
* Returns the stream.
*
* @return resource
*/
public function getStream()
{
return $this->stream;
}
/**
* Gets the total available length.
*
* @return int
*/
public function getTotalLength()
{
if ($this->totalLength === null) {
$stat = \fstat($this->stream);
$this->totalLength = $stat['size'];
}
return $this->totalLength;
}
/**
* Resets the buffer to a position and re-read the buffer with the given length.
*
* If the $pos parameter is negative the start buffer position will be the $pos'th position from
* the end of the file.
*
* If the $pos parameter is negative and the absolute value is bigger then the totalLength of
* the file $pos will set to zero.
*
* @param int|null $pos Start position of the new buffer
* @param int $length Length of the new buffer. Mustn't be negative
*/
public function reset($pos = 0, $length = 200)
{
if ($pos === null) {
$pos = $this->position + $this->offset;
} elseif ($pos < 0) {
$pos = \max(0, $this->getTotalLength() + $pos);
}
\fseek($this->stream, $pos);
$this->position = $pos;
$this->buffer = $length > 0 ? \fread($this->stream, $length) : '';
$this->bufferLength = \strlen($this->buffer);
$this->offset = 0;
// If a stream wrapper is in use it is possible that
// length values > 8096 will be ignored, so use the
// increaseLength()-method to correct that behavior
if ($this->bufferLength < $length && $this->increaseLength($length - $this->bufferLength)) {
// increaseLength parameter is $minLength, so cut to have only the required bytes in the buffer
$this->buffer = \substr($this->buffer, 0, $length);
$this->bufferLength = \strlen($this->buffer);
}
}
/**
* Ensures bytes in the buffer with a specific length and location in the file.
*
* @param int $pos
* @param int $length
* @see reset()
*/
public function ensure($pos, $length)
{
if (
$pos >= $this->position
&& $pos < ($this->position + $this->bufferLength)
&& ($this->position + $this->bufferLength) >= ($pos + $length)
) {
$this->offset = $pos - $this->position;
} else {
$this->reset($pos, $length);
}
}
/**
* Forcefully read more data into the buffer.
*
* @param int $minLength
* @return bool Returns false if the stream reaches the end
*/
public function increaseLength($minLength = 100)
{
$length = \max($minLength, 100);
if (\feof($this->stream) || $this->getTotalLength() === $this->position + $this->bufferLength) {
return false;
}
$newLength = $this->bufferLength + $length;
do {
$this->buffer .= \fread($this->stream, $newLength - $this->bufferLength);
$this->bufferLength = \strlen($this->buffer);
} while (($this->bufferLength !== $newLength) && !\feof($this->stream));
return true;
}
}
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