source/graphics/imageloader.h

   1 #ifndef MSP_GRAPHICS_IMAGELOADER_H_
   2 #define MSP_GRAPHICS_IMAGELOADER_H_
   3
   4 #include "image.h"
   5
   6 namespace Msp {
   7 namespace Graphics {
   8
   9 class unsupported_image_format: public std::runtime_error
  10 {
  11 public:
  12         unsupported_image_format(const std::string &w): std::runtime_error(w) { }
  13         virtual ~unsupported_image_format() throw() { }
  14 };
  15
  16 class bad_image_data: public std::runtime_error
  17 {
  18 public:
  19         bad_image_data(const std::string &w): std::runtime_error(w) { }
  20         virtual ~bad_image_data() throw() { }
  21 };
  22
  23
  24 class ImageLoader
  25 {
  26 protected:
  27         class RegisterBase
  28         {
  29         protected:
  30                 RegisterBase() { }
  31         public:
  32                 virtual ~RegisterBase() { }
  33
  34                 virtual unsigned get_signature_size() const = 0;
  35                 virtual bool detect(const std::string &) const = 0;
  36                 virtual ImageLoader *create(IO::Seekable &) const = 0;
  37         };
  38
  39         template<typename T>
  40         class RegisteredLoader: public RegisterBase
  41         {
  42         public:
  43                 virtual unsigned get_signature_size() const { return T::get_signature_size(); }
  44                 virtual bool detect(const std::string &s) const { return T::detect(s); }
  45                 virtual ImageLoader *create(IO::Seekable &io) const { return new T(io); }
  46         };
  47
  48         struct Registry
  49         {
  50                 std::list<RegisterBase *> loaders;
  51                 bool changed;
  52
  53                 Registry();
  54                 ~Registry();
  55         };
  56
  57 private:
  58         IO::Base *source;
  59
  60 protected:
  61         ImageLoader();
  62 public:
  63         virtual ~ImageLoader();
  64
  65         static ImageLoader *open_file(const std::string &);
  66         static ImageLoader *open_io(IO::Seekable &);
  67
  68         virtual void load(Image::Data &) = 0;
  69
  70         template<typename T>
  71         static void register_loader();
  72 private:
  73         static Registry &get_registry();
  74
  75         static bool signature_size_compare(RegisterBase *, RegisterBase *);
  76 };
  77
  78 template<typename T>
  79 void ImageLoader::register_loader()
  80 {
  81         Registry &registry = get_registry();
  82         registry.loaders.push_back(new RegisteredLoader<T>);
  83         registry.changed = true;
  84 }
  85
  86 } // namespace Graphics
  87 } // namespace Msp
  88
  89 #endif