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 public:
  27         enum State
  28         {
  29                 INITIAL,
  30                 FINISHED
  31         };
  32
  33 protected:
  34         class RegisterBase
  35         {
  36         protected:
  37                 RegisterBase() { }
  38         public:
  39                 virtual ~RegisterBase() { }
  40
  41                 virtual unsigned get_signature_size() const = 0;
  42                 virtual bool detect(const std::string &) const = 0;
  43                 virtual ImageLoader *create(IO::Seekable &) const = 0;
  44         };
  45
  46         template<typename T>
  47         class RegisteredLoader: public RegisterBase
  48         {
  49         public:
  50                 virtual unsigned get_signature_size() const { return T::get_signature_size(); }
  51                 virtual bool detect(const std::string &s) const { return T::detect(s); }
  52                 virtual ImageLoader *create(IO::Seekable &io) const { return new T(io); }
  53         };
  54
  55         struct Registry
  56         {
  57                 std::list<RegisterBase *> loaders;
  58                 bool changed;
  59
  60                 Registry();
  61                 ~Registry();
  62         };
  63
  64 private:
  65         IO::Base *source;
  66         State state;
  67
  68 protected:
  69         ImageLoader();
  70 public:
  71         virtual ~ImageLoader();
  72
  73         static ImageLoader *open_file(const std::string &);
  74         static ImageLoader *open_io(IO::Seekable &);
  75
  76         virtual void load(Image::Data &);
  77 protected:
  78         virtual void load_(Image::Data &) = 0;
  79
  80 public:
  81         State get_state() const { return state; }
  82
  83         template<typename T>
  84         static void register_loader();
  85 private:
  86         static Registry &get_registry();
  87
  88         static bool signature_size_compare(RegisterBase *, RegisterBase *);
  89 };
  90
  91 template<typename T>
  92 void ImageLoader::register_loader()
  93 {
  94         Registry &registry = get_registry();
  95         registry.loaders.push_back(new RegisteredLoader<T>);
  96         registry.changed = true;
  97 }
  98
  99 } // namespace Graphics
 100 } // namespace Msp
 101
 102 #endif