Merge pull request #5 from genkgo/single_gz_stream

use a single gz stream by encoding chunks

Author: frederikbosch

src/TarGzReader.php

@@ -35,6 +35,11 @@ public function __construct(TarReader $tarReader, int $level = -1)
      */
     public function read(int $blockSize): \Generator
     {
+        $deflateContext = \deflate_init(\ZLIB_ENCODING_GZIP, ['level' => $this->level]);
+        if ($deflateContext === false) {
+            throw new \UnexpectedValueException('Cannot open deflate context');
+        }
+
         $generator = $this->tarReader->read($blockSize);
         foreach ($generator as $stream) {
             while ($stream->eof() === false) {
@@ -43,16 +48,28 @@ public function read(int $blockSize): \Generator
                     throw new \UnexpectedValueException('Failed to read tar stream');
                 }
 
-                $encoded = \gzencode($data, $this->level);
-                if (!$encoded) {
+                $encoded = \deflate_add($deflateContext, $data, \ZLIB_NO_FLUSH);
+                if ($encoded === false) {
                     throw new \UnexpectedValueException('Failed to encode tar data');
                 }
 
-                $stream = new \SplTempFileObject();
-                $stream->fwrite($encoded);
-                $stream->rewind();
-                yield $stream;
+                if ($encoded !== '') {
+                    $stream = new \SplTempFileObject();
+                    $stream->fwrite($encoded);
+                    $stream->rewind();
+                    yield $stream;
+                }
             }
         }
+
+        $encoded = \deflate_add($deflateContext, '', \ZLIB_FINISH);
+        if ($encoded === false) {
+            throw new \UnexpectedValueException('Failed to encode last chunk of tar data');
+        }
+
+        $stream = new \SplTempFileObject();
+        $stream->fwrite($encoded);
+        $stream->rewind();
+        yield $stream;
     }
 }