wip

HLS/StreamReader.php

@@ -0,0 +1,104 @@
+<?php
+/**
+ * Base class for streaming media segment readers
+ *
+ * @file
+ * @ingroup HLS
+ */
+
+namespace MediaWiki\TimedMediaHandler\HLS;
+
+use Exception;
+
+/**
+ * Base class for reading/writing a media file with wrappers
+ * for exception handling and possible multi usage.
+ */
+class StreamReader {
+	/**
+	 * @var resource
+	 */
+	protected $file;
+
+	protected int $pos;
+
+	/**
+	 * @param resource $file
+	 */
+	public function __construct( $file ) {
+		if ( get_resource_type( $file ) !== 'stream' ) {
+			throw new Exception( 'Invalid file stream' );
+		}
+		$this->file = $file;
+		$this->pos = $this->tell();
+	}
+
+	private function tell(): int {
+		return ftell( $this->file );
+	}
+
+	public function pos(): int {
+		return $this->pos;
+	}
+
+	/**
+	 * Seek to given absolute file position.
+	 * @throws Exception on error
+	 */
+	public function seek( int $pos ): void {
+		$this->pos = intval( $pos );
+
+		if ( $this->pos === $this->tell() ) {
+			return;
+		}
+		$retval = fseek( $this->file, $this->pos, SEEK_SET );
+
+		if ( $retval < 0 ) {
+			throw new Exception( "Failed to seek to $this->pos bytes" );
+		}
+	}
+
+	/**
+	 * Read $len bytes or return null on EOF/short read.
+	 * @throws Exception on error
+	 */
+	public function read( int $len ): ?string {
+		$this->seek( $this->pos );
+		$bytes = fread( $this->file, $len );
+		if ( $bytes === false ) {
+			throw new Exception( "Read error for $len bytes at $this->pos" );
+		}
+		if ( strlen( $bytes ) < $len ) {
+			return null;
+		}
+		$this->pos += strlen( $bytes );
+		return $bytes;
+	}
+
+	/**
+	 * Read exactly $len bytes
+	 * @throws Exception on error or short read
+	 */
+	public function readExactly( int $len ): string {
+		$bytes = $this->read( $len );
+		if ( $bytes === null ) {
+			throw new Exception( "Short read for $len bytes at $this->pos" );
+		}
+		return $bytes;
+	}
+
+	/**
+	 * Write the given data and return number of bytes written.
+	 * Short writes are possible on network connections, in theory.
+	 * @throws Exception on error
+	 */
+	public function write( string $bytes ): int {
+		$this->seek( $this->pos );
+		$len = strlen( $bytes );
+		$nbytes = fwrite( $this->file, $bytes );
+		if ( $nbytes === false ) {
+			throw new Exception( "Write error for $len bytes at $this->pos" );
+		}
+		return $nbytes;
+	}
+}