Allow compression level of GzipOutputStream to be configured.

1 files changed, 35 insertions, 4 deletions

diff --git a/src/google/protobuf/io/gzip_stream.h b/src/google/protobuf/io/gzip_stream.h
index 50a2ad70..65dbc5b5 100644
--- a/src/google/protobuf/io/gzip_stream.h
+++ b/src/google/protobuf/io/gzip_stream.h
@@ -117,11 +117,39 @@ class LIBPROTOBUF_EXPORT GzipOutputStream : public ZeroCopyOutputStream {
     ZLIB = 2,
   };
 
-  // buffer_size and format may be -1 for default of 64kB and GZIP format
-  explicit GzipOutputStream(
+  struct Options {
+    // Defaults to GZIP.
+    Format format;
+
+    // What size buffer to use internally.  Defaults to 64kB.
+    int buffer_size;
+
+    // A number between 0 and 9, where 0 is no compression and 9 is best
+    // compression.  Defaults to Z_DEFAULT_COMPRESSION (see zlib.h).
+    int compression_level;
+
+    // Defaults to Z_DEFAULT_STRATEGY.  Can also be set to Z_FILTERED,
+    // Z_HUFFMAN_ONLY, or Z_RLE.  See the documentation for deflateInit2 in
+    // zlib.h for definitions of these constants.
+    int compression_strategy;
+
+    Options();  // Initializes with default values.
+  };
+
+  // Create a GzipOutputStream with default options.
+  explicit GzipOutputStream(ZeroCopyOutputStream* sub_stream);
+
+  // Create a GzipOutputStream with the given options.
+  GzipOutputStream(
       ZeroCopyOutputStream* sub_stream,
-      Format format = GZIP,
-      int buffer_size = -1);
+      const Options& options);
+
+  // DEPRECATED:  Use one of the above constructors instead.
+  GzipOutputStream(
+      ZeroCopyOutputStream* sub_stream,
+      Format format,
+      int buffer_size = -1) GOOGLE_ATTRIBUTE_DEPRECATED;
+
   virtual ~GzipOutputStream();
 
   // Return last error message or NULL if no error.
@@ -161,6 +189,9 @@ class LIBPROTOBUF_EXPORT GzipOutputStream : public ZeroCopyOutputStream {
   void* input_buffer_;
   size_t input_buffer_length_;
 
+  // Shared constructor code.
+  void Init(ZeroCopyOutputStream* sub_stream, const Options& options);
+
   // Do some compression.
   // Takes zlib flush mode.
   // Returns zlib error code.