Add support for zlib/level context option

NEWS

@@ -110,4 +110,7 @@ PHP                                                                        NEWS
   . Fixed unzserialize(), to disable creation of unsupported data structures
     through manually crafted strings. (Dmitry)
 
+- Zlib:
+  . Added zlib/level context option for compress.zlib wrapper. (Sara)
+
 <<< NOTE: Insert NEWS from last stable release here prior to actual release! >>>

ext/zlib/tests/zlib_wrapper_level.phpt

@@ -0,0 +1,36 @@
+--TEST--
+compress.zlib:// wrapper with compression level
+--SKIPIF--
+<?php in_array('compress.zlib', stream_get_wrappers()) || print 'skip No zlib wrapper';
+--FILE--
+<?php declare(strict_types=1);
+
+$filename = tempnam(sys_get_temp_dir(), "php-zlib-test-");
+$thisfile = file_get_contents(__FILE__);
+
+function write_at_level(int $level) {
+  global $filename, $thisfile;
+
+  $ctx = stream_context_create(['zlib' => ['level' => $level] ]);
+  $fp = fopen("compress.zlib://$filename", 'w', false, $ctx);
+  for ($i = 0; $i < 10; ++$i) {
+    fwrite($fp, $thisfile);
+  }
+  fclose($fp);
+  $size = filesize($filename);
+  unlink($filename);
+  return $size;
+}
+
+$size1 = write_at_level(1);
+$size9 = write_at_level(9);
+
+var_dump(10 * strlen($thisfile));
+var_dump($size1);
+var_dump($size9);
+var_dump($size9 < $size1);
+--EXPECTF--
+int(%d)
+int(%d)
+int(%d)
+bool(true)

ext/zlib/zlib_fopen_wrapper.c

@@ -141,6 +141,11 @@ php_stream *php_stream_gzopen(php_stream_wrapper *wrapper, const char *path, con
 			self->gz_file = gzdopen(dup(fd), mode);
 
 			if (self->gz_file) {
+				zval *zlevel = context ? php_stream_context_get_option(context, "zlib", "level") : NULL;
+				if (zlevel && (Z_OK != gzsetparams(self->gz_file, zval_get_long(zlevel), Z_DEFAULT_STRATEGY))) {
+					php_error(E_WARNING, "failed setting compression level");
+				}
+
 				stream = php_stream_alloc_rel(&php_stream_gzio_ops, self, 0, mode);
 				if (stream) {
 					stream->flags |= PHP_STREAM_FLAG_NO_BUFFER;