loader png: code refactoring

Seperate behaviors open/read/close,
free/close pngimage properly,
add copyright for files.

There still left one optimization point by applying Task.

src/loaders/png/tvgPngLoader.cpp

@@ -1,8 +1,34 @@
-#include <fstream>
+/*
-#include <string>
+ * Copyright (c) 2020-2021 Samsung Electronics Co., Ltd. All rights reserved.
+
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
 #include "tvgLoaderMgr.h"
 #include "tvgPngLoader.h"
-// #include "png.h"
+
+PngLoader::PngLoader()
+{
+    image = static_cast<png_imagep>(calloc(1, sizeof(png_image)));
+    image->version = PNG_IMAGE_VERSION;
+    image->opaque = NULL;
+}
 
 PngLoader::~PngLoader()
 {
@@ -10,43 +36,44 @@ PngLoader::~PngLoader()
         free((void*)content);
         content = nullptr;
     }
+    free(image);
 }
 
 bool PngLoader::open(const string& path)
 {
-    png_image image;
+    image->opaque = NULL;
-    image.version = PNG_IMAGE_VERSION;
+
-    image.opaque = NULL;
+    if (!png_image_begin_read_from_file(image, path.c_str())) return false;
+
+    vw = w = image->width;
+    vh = h = image->height;
 
-    if (!png_image_begin_read_from_file(&image, path.c_str())) return false;
-    w = image.width;
-    h = image.height;
-    vw = w;
-    vh = h;
-    png_bytep buffer;
-    image.format = PNG_FORMAT_BGRA;
-    buffer = static_cast<png_bytep>(malloc(PNG_IMAGE_SIZE(image)));
-    if (!buffer) {
-        // out of memory, only time when libpng doesnt free its data
-        png_image_free(&image);
-        return false;
-    }
-    if (!png_image_finish_read(&image, NULL, buffer, 0, NULL)) return false;
-    content = reinterpret_cast<uint32_t*>(buffer);
     return true;
 }
 
 bool PngLoader::read()
 {
+    png_bytep buffer;
+    image->format = PNG_FORMAT_BGRA;
+    buffer = static_cast<png_bytep>(malloc(PNG_IMAGE_SIZE((*image))));
+    if (!buffer) {
+        // out of memory, only time when libpng doesnt free its data
+        png_image_free(image);
+        return false;
+    }
+    if (!png_image_finish_read(image, NULL, buffer, 0, NULL)) return false;
+    content = reinterpret_cast<uint32_t*>(buffer);
+
     return true;
 }
 
 bool PngLoader::close()
 {
+    png_image_free(image);
     return true;
 }
 
 const uint32_t* PngLoader::pixels()
 {
     return this->content;
-}
+}

src/loaders/png/tvgPngLoader.h

@@ -1,13 +1,37 @@
+/*
+ * Copyright (c) 2020-2021 Samsung Electronics Co., Ltd. All rights reserved.
+
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
 #ifndef _TVG_PNG_LOADER_H_
 #define _TVG_PNG_LOADER_H_
 
 #include <png.h>
 
+//OPTIMIZE ME: Use Task?
 class PngLoader : public Loader
 {
 public:
+    png_imagep image = nullptr;
     const uint32_t* content = nullptr;
 
+    PngLoader();
     ~PngLoader();
 
     using Loader::open;
@@ -18,5 +42,4 @@ public:
     const uint32_t* pixels() override;
 };
 
-
 #endif //_TVG_PNG_LOADER_H_