init

vendor/binsoul/net-mqtt/src/PacketStream.php

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+<?php
+
+namespace BinSoul\Net\Mqtt;
+
+use BinSoul\Net\Mqtt\Exception\EndOfStreamException;
+
+/**
+ * Provides methods to operate on a stream of bytes.
+ */
+class PacketStream
+{
+    /** @var string */
+    private $data;
+    /** @var int */
+    private $position;
+
+    /**
+     * Constructs an instance of this class.
+     *
+     * @param string $data initial data of the stream
+     */
+    public function __construct($data = '')
+    {
+        $this->data = $data;
+        $this->position = 0;
+    }
+
+    /**
+     * @return string
+     */
+    public function __toString()
+    {
+        return $this->data;
+    }
+
+    /**
+     * Returns the desired number of bytes.
+     *
+     * @param int $count
+     *
+     * @throws EndOfStreamException
+     *
+     * @return string
+     */
+    public function read($count)
+    {
+        $contentLength = strlen($this->data);
+        if ($this->position > $contentLength || $count > $contentLength - $this->position) {
+            throw new EndOfStreamException(
+                sprintf(
+                    'End of stream reached when trying to read %d bytes. content length=%d, position=%d',
+                    $count,
+                    $contentLength,
+                    $this->position
+                )
+            );
+        }
+
+        $chunk = substr($this->data, $this->position, $count);
+        if ($chunk === false) {
+            $chunk = '';
+        }
+
+        $readBytes = strlen($chunk);
+        $this->position += $readBytes;
+
+        return $chunk;
+    }
+
+    /**
+     * Returns a single byte.
+     *
+     * @return int
+     */
+    public function readByte()
+    {
+        return ord($this->read(1));
+    }
+
+    /**
+     * Returns a single word.
+     *
+     * @return int
+     */
+    public function readWord()
+    {
+        return ($this->readByte() << 8) + $this->readByte();
+    }
+
+    /**
+     * Returns a length prefixed string.
+     *
+     * @return string
+     */
+    public function readString()
+    {
+        $length = $this->readWord();
+
+        return $this->read($length);
+    }
+
+    /**
+     * Appends the given value.
+     *
+     * @param string $value
+     */
+    public function write($value)
+    {
+        $this->data .= $value;
+    }
+
+    /**
+     * Appends a single byte.
+     *
+     * @param int $value
+     */
+    public function writeByte($value)
+    {
+        $this->write(chr($value));
+    }
+
+    /**
+     * Appends a single word.
+     *
+     * @param int $value
+     */
+    public function writeWord($value)
+    {
+        $this->write(chr(($value & 0xFFFF) >> 8));
+        $this->write(chr($value & 0xFF));
+    }
+
+    /**
+     * Appends a length prefixed string.
+     *
+     * @param string $string
+     */
+    public function writeString($string)
+    {
+        $this->writeWord(strlen($string));
+        $this->write($string);
+    }
+
+    /**
+     * Returns the length of the stream.
+     *
+     * @return int
+     */
+    public function length()
+    {
+        return strlen($this->data);
+    }
+
+    /**
+     * Returns the number of bytes until the end of the stream.
+     *
+     * @return int
+     */
+    public function getRemainingBytes()
+    {
+        return $this->length() - $this->position;
+    }
+
+    /**
+     * Returns the whole content of the stream.
+     *
+     * @return string
+     */
+    public function getData()
+    {
+        return $this->data;
+    }
+
+    /**
+     * Changes the internal position of the stream relative to the current position.
+     *
+     * @param int $offset
+     */
+    public function seek($offset)
+    {
+        $this->position += $offset;
+    }
+
+    /**
+     * Returns the internal position of the stream.
+     *
+     * @return int
+     */
+    public function getPosition()
+    {
+        return $this->position;
+    }
+
+    /**
+     * Sets the internal position of the stream.
+     *
+     * @param int $value
+     */
+    public function setPosition($value)
+    {
+        $this->position = $value;
+    }
+
+    /**
+     * Removes all bytes from the beginning to the current position.
+     */
+    public function cut()
+    {
+        $this->data = substr($this->data, $this->position);
+        if ($this->data === false) {
+            $this->data = '';
+        }
+
+        $this->position = 0;
+    }
+}