add read attributes support

test_attributes.c

@@ -83,7 +83,14 @@ void my_create_dataset(char* arrayName)
 
     short shortint = 42;
     z5writeAttributesshort(arrayName, "short", &shortint);
-
+
+    // testing read all attributes
+    z5readAttributes(arrayName);
+
+    // testing read attributes by providing keys
+    char *keysinput[2] = {"uint", "double"};
+    z5readAttributesWithKeys(arrayName, keysinput, 2); 
+
     printf("after assert\n");
 }
 

z5wrapper.cc

@@ -261,7 +261,43 @@ namespace z5 {
         fs::path filename(path_s);
         fs::remove_all(filename);
     }
+
+    // read attributes //
+    void z5readAttributesWithKeys(char *path, char *keys[], int keys_sz)
+    {
+        std::string path_s(path);
+        bool asZarr = true;
+        handle::Handle cHandle(path_s);
+        nlohmann::json j;
+	std::vector<std::string> keys_s;
+	for (size_t i = 0; i < keys_sz; i++)
+	{
+		std::string keys_tmp(keys[i]);
+		keys_s.push_back(keys_tmp);
+	}
+	readAttributes(cHandle, keys_s, j);
+#ifdef _JASON_OUTPUT_	
+	for (auto it = j.begin(); it != j.end(); ++it)
+	{
+    		std::cout << "key: " << it.key() << ", value:" << it.value() << '\n';
+	}
+#endif
+    }
 
+    void z5readAttributes(char *path)
+    {
+        std::string path_s(path);
+        bool asZarr = true;
+        handle::Handle cHandle(path_s);
+        nlohmann::json j;
+	readAttributes(cHandle, j);
+#ifdef _JASON_OUTPUT_	
+	for (auto it = j.begin(); it != j.end(); ++it)
+	{
+    		std::cout << "key: " << it.key() << ", value:" << it.value() << '\n';
+	}
+#endif	
+    }
 }
 
 }

z5wrapper.h

@@ -40,6 +40,8 @@ namespace z5 {
 
         size_t z5GetFileSize(char *path);
 
+	void z5Delete(char *path );
+
 	void z5writeAttributesString(char *path, const char *name, const char *value);
 
 	void z5writeAttributesshort(char *path, const char *name, const short *value);
@@ -61,8 +63,12 @@ namespace z5 {
 	void z5writeAttributesulonglong(char *path, const char *name, const unsigned long long *value);
 
 	void z5writeAttributesuint(char *path, const char *name, const unsigned int *value);
-
-	void z5Delete(char *path );
+
+	// read attributes //
+
+	void z5readAttributesWithKeys(char *path, char *keys[], int keys_sz); 
+
+	void z5readAttributes(char *path); 
 #ifdef __cplusplus
     }
 }