Add basic tiled image type.

TODO.md

@@ -14,4 +14,4 @@
 [ ] Cut image in tiles
 
 # Quality
-[ ] Interpolate using SIMD, SSE
+[X] Interpolate using SIMD, SSE (no big gain)

rotation.cpp

@@ -9,7 +9,6 @@
 
 #include <xmmintrin.h>
 
-
 using namespace std;
 
 
@@ -77,7 +76,7 @@ struct Image {
     }
   }
 
-  bool save(string const& path)
+  bool save(string const& path) const
   {
     ofstream os(path);
     if (!os.is_open())
@@ -111,7 +110,7 @@ struct Image {
   }
 
 
-  private:
+  protected:
     bool read_header(std::ifstream& istr)
     {
       // check magic
@@ -169,7 +168,7 @@ struct Image {
       return true;
     }
 
-    bool write_header(std::ofstream& ostr)
+    bool write_header(std::ofstream& ostr) const
     {
       ostr << "P6" << endl;
       ostr << width << " " << height << endl;
@@ -177,7 +176,7 @@ struct Image {
       return true;
     }
 
-    bool read_body(std::ifstream& istr)
+    virtual bool read_body(std::ifstream& istr)
     {
       unsigned int const nb_pixels = width * height;
       buffer = new uint8_t[nb_pixels * 3];
@@ -192,7 +191,7 @@ struct Image {
       return true;
     }
 
-    bool write_body(std::ofstream& ostr)
+    virtual bool write_body(std::ofstream& ostr) const
     {
       unsigned int const nb_pixels = width * height;
       uint8_t* buf_index = buffer;
@@ -206,6 +205,121 @@ struct Image {
     }
 };
 
+template<unsigned int W, unsigned int H>
+struct TiledImage : public Image {
+  uint8_t** tiles;
+  unsigned int static const tile_w = W;
+  unsigned int static const tile_h = H;
+  unsigned int static const tile_size = W * H;
+  unsigned int nb_col_tile;
+  unsigned int nb_row_tile;
+
+  TiledImage()
+  : Image()
+  , tiles(NULL)
+  , nb_col_tile(0)
+  , nb_row_tile(0)
+  {}
+
+  TiledImage(unsigned int w, unsigned int h)
+  {
+    allocate_memory(w, h);
+  }
+
+  TiledImage(string const& path)
+  : TiledImage()
+  {
+      ifstream is(path);
+      if (!is.is_open())
+      {
+          cerr << "Cannot open file '" << path << "'" << endl;
+          abort();
+      }
+
+      if (!this->read_header(is))
+      {
+          cerr << "Invalid header." << endl;
+          abort();
+      }
+
+      if (!this->read_body(is))
+      {
+          // TODO: delete tiles
+          cerr << "Invalid header." << endl;
+          abort();
+      }
+  }
+
+  protected:
+    void allocate_memory(unsigned int w, unsigned int h)
+    {
+      width = w;
+      height = h;
+
+      nb_col_tile = width / tile_w;
+      if (width % tile_w != 0)
+        ++nb_col_tile;
+
+      nb_row_tile = height / tile_h;
+      if (height % tile_h != 0)
+        ++nb_row_tile;
+
+      unsigned int const nb_tiles = nb_col_tile * nb_row_tile;
+      tiles = new uint8_t*[nb_tiles];
+      for (unsigned int i = 0; i < nb_tiles; ++i)
+      {
+        tiles[i] = new uint8_t[tile_w * tile_h * 3];
+        memset(tiles[i], 0, tile_w * tile_h * 3 * sizeof (uint8_t));
+      }
+    }
+
+    virtual bool read_body(std::ifstream& istr)
+    {
+      this->allocate_memory(width, height);
+
+      unsigned int const tile_width = tile_w * 3;
+
+      // Pixel loading
+      for (unsigned int j = 0; j < height; ++j)
+        for (unsigned int i = 0; i < width; ++i)
+        {
+          unsigned int const tile_index = (j / tile_h) * nb_col_tile + (i / tile_w);
+          uint8_t* tile = tiles[tile_index];
+          unsigned int const tile_j = j % tile_h;
+          unsigned int const tile_i = i % tile_w;
+          // if (i % 3 == 0)
+          //   cout << "pixel (" << i / 3 << ", " << j << ") goes in tile (" << i / (tile_w * 3) << ", " << j / tile_h << ")" << endl;
+          tile +=  tile_j * tile_width + (tile_i * 3);
+          *(tile++) = istr.get();
+          *(tile++) = istr.get();
+          *(tile++) = istr.get();
+        }
+
+      return true;
+    }
+
+    virtual bool write_body(std::ofstream& ostr) const override
+    {
+      unsigned int const tile_width = tile_w * 3;
+
+      for (unsigned int j = 0; j < height; ++j)
+        for (unsigned int i = 0; i < width; ++i)
+        {
+          unsigned int const tile_index = (j / tile_h) * nb_col_tile + (i / tile_w);
+          uint8_t* tile = tiles[tile_index];
+          unsigned int const tile_j = j % tile_h;
+          unsigned int const tile_i = i % tile_w;
+          tile +=  tile_j * tile_width + (tile_i * 3);
+          ostr << (char) *(tile++);
+          ostr << (char) *(tile++);
+          ostr << (char) *(tile++);
+        }
+
+      return true;
+    }
+
+};
+
 
 
 //
@@ -742,6 +856,10 @@ int main(int argc, char* argv[])
     }
   }
 
+  TiledImage<8, 8> tiled_img(argv[1]);
+  tiled_img.save("tiled.ppm");
+  return 0;
+
   Image img(argv[1]);
 
   for (double rotation = 0; rotation < 360; rotation += 5)
@@ -754,6 +872,7 @@ int main(int argc, char* argv[])
     auto const after = chrono::high_resolution_clock::now();
     auto const duration_ms = std::chrono::duration_cast<std::chrono::milliseconds>(after - before);
     cout << "rotate(" << rotation << "): " << duration_ms.count() << " ms" << endl;
+    // TODO: compare implementation
 
     stringstream filename;
     // filename << "/tmp/";