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