Merge pull request #9209 from alalek:fix_persistence_format

modules/core/include/opencv2/core/persistence.hpp

@@ -462,6 +462,11 @@ public:
      */
     static String getDefaultObjectName(const String& filename);
 
+    /** @brief Returns the current format.
+     * @returns The current format, see FileStorage::Mode
+     */
+    CV_WRAP int getFormat() const;
+
     Ptr<CvFileStorage> fs; //!< the underlying C FileStorage structure
     String elname; //!< the currently written element
     std::vector<char> structs; //!< the stack of written structures

modules/core/src/persistence.cpp

@@ -4270,11 +4270,25 @@ cvOpenFileStorage( const char* query, CvMemStorage* dststorage, int flags, const
 
         if( fmt == CV_STORAGE_FORMAT_AUTO && filename )
         {
-            const char* dot_pos = strrchr( filename, '.' );
+            const char* dot_pos = NULL;
+            const char* dot_pos2 = NULL;
+            // like strrchr() implementation, but save two last positions simultaneously
+            for (const char* pos = filename; pos[0] != 0; pos++)
+            {
+                if (pos[0] == '.')
+                {
+                    dot_pos2 = dot_pos;
+                    dot_pos = pos;
+                }
+            }
+            if (cv_strcasecmp(dot_pos, ".gz") && dot_pos2 != NULL)
+            {
+                dot_pos = dot_pos2;
+            }
             fs->fmt
-                = cv_strcasecmp( dot_pos, ".xml" )
+                = (cv_strcasecmp(dot_pos, ".xml") || cv_strcasecmp(dot_pos, ".xml.gz"))
                 ? CV_STORAGE_FORMAT_XML
-                : cv_strcasecmp( dot_pos, ".json" )
+                : (cv_strcasecmp(dot_pos, ".json") || cv_strcasecmp(dot_pos, ".json.gz"))
                 ? CV_STORAGE_FORMAT_JSON
                 : CV_STORAGE_FORMAT_YAML
                 ;
@@ -6920,6 +6934,12 @@ FileNode FileStorage::root(int streamidx) const
     return isOpened() ? FileNode(fs, cvGetRootFileNode(fs, streamidx)) : FileNode();
 }
 
+int FileStorage::getFormat() const
+{
+    CV_Assert(!fs.empty());
+    return fs->fmt & FORMAT_MASK;
+}
+
 FileStorage& operator << (FileStorage& fs, const String& str)
 {
     CV_TRACE_REGION_VERBOSE();

modules/core/test/test_io.cpp

@@ -1236,3 +1236,59 @@ TEST(Core_InputOutput, FileStorage_DMatch_vector_vector)
         }
     }
 }
+
+TEST(Core_InputOutput, FileStorage_format_xml)
+{
+    FileStorage fs;
+    fs.open("opencv_storage.xml", FileStorage::WRITE | FileStorage::MEMORY);
+    EXPECT_EQ(FileStorage::FORMAT_XML, fs.getFormat());
+}
+
+TEST(Core_InputOutput, FileStorage_format_xml_gz)
+{
+    FileStorage fs;
+    fs.open("opencv_storage.xml.gz", FileStorage::WRITE | FileStorage::MEMORY);
+    EXPECT_EQ(FileStorage::FORMAT_XML, fs.getFormat());
+}
+
+TEST(Core_InputOutput, FileStorage_format_json)
+{
+    FileStorage fs;
+    fs.open("opencv_storage.json", FileStorage::WRITE | FileStorage::MEMORY);
+    EXPECT_EQ(FileStorage::FORMAT_JSON, fs.getFormat());
+}
+
+TEST(Core_InputOutput, FileStorage_format_json_gz)
+{
+    FileStorage fs;
+    fs.open("opencv_storage.json.gz", FileStorage::WRITE | FileStorage::MEMORY);
+    EXPECT_EQ(FileStorage::FORMAT_JSON, fs.getFormat());
+}
+
+TEST(Core_InputOutput, FileStorage_format_yaml)
+{
+    FileStorage fs;
+    fs.open("opencv_storage.yaml", FileStorage::WRITE | FileStorage::MEMORY);
+    EXPECT_EQ(FileStorage::FORMAT_YAML, fs.getFormat());
+}
+
+TEST(Core_InputOutput, FileStorage_format_yaml_gz)
+{
+    FileStorage fs;
+    fs.open("opencv_storage.yaml.gz", FileStorage::WRITE | FileStorage::MEMORY);
+    EXPECT_EQ(FileStorage::FORMAT_YAML, fs.getFormat());
+}
+
+TEST(Core_InputOutput, FileStorage_format_yml)
+{
+    FileStorage fs;
+    fs.open("opencv_storage.yml", FileStorage::WRITE | FileStorage::MEMORY);
+    EXPECT_EQ(FileStorage::FORMAT_YAML, fs.getFormat());
+}
+
+TEST(Core_InputOutput, FileStorage_format_yml_gz)
+{
+    FileStorage fs;
+    fs.open("opencv_storage.yml.gz", FileStorage::WRITE | FileStorage::MEMORY);
+    EXPECT_EQ(FileStorage::FORMAT_YAML, fs.getFormat());
+}