source/graphics/imageloader.cpp

   1 #include <msp/core/refptr.h>
   2 #include <msp/io/file.h>
   3 #include <msp/strings/format.h>
   4 #include "imageloader.h"
   5
   6 using namespace std;
   7
   8 namespace Msp {
   9 namespace Graphics {
  10
  11 bool ImageLoader::registered_loaders_changed = false;
  12
  13 ImageLoader::ImageLoader():
  14         source(0)
  15 { }
  16
  17 ImageLoader::~ImageLoader()
  18 {
  19         delete source;
  20 }
  21
  22 ImageLoader *ImageLoader::open_file(const string &fn)
  23 {
  24         try
  25         {
  26                 RefPtr<IO::BufferedFile> file = new IO::BufferedFile(fn);
  27                 ImageLoader *loader = open_io(*file);
  28                 loader->source = file.release();
  29                 return loader;
  30         }
  31         catch(const unsupported_image_format &e)
  32         {
  33                 throw unsupported_image_format(format("%s: %s", fn, e.what()));
  34         }
  35 }
  36
  37 ImageLoader *ImageLoader::open_io(IO::Seekable &io)
  38 {
  39         list<RegisterBase *> &loaders = get_registered_loaders();
  40         if(registered_loaders_changed)
  41         {
  42                 registered_loaders_changed = false;
  43                 loaders.sort(signature_size_compare);
  44         }
  45
  46         if(loaders.empty())
  47                 throw unsupported_image_format("no loaders");
  48
  49         vector<char> sig_buf(loaders.back()->get_signature_size());
  50         unsigned sig_len = io.read(&sig_buf[0], sig_buf.size());
  51         string signature(sig_buf.begin(), sig_buf.end());
  52
  53         ImageLoader *loader = 0;
  54         for(list<RegisterBase *>::const_iterator i=loaders.begin(); (!loader && i!=loaders.end()); ++i)
  55                 if((*i)->detect(signature))
  56                         loader = (*i)->create(io);
  57
  58         io.seek(0, IO::S_BEG);
  59
  60         if(!loader)
  61         {
  62                 string sig_hex;
  63                 for(unsigned i=0; i<sig_len; ++i)
  64                 {
  65                         if(i)
  66                                 sig_hex += ' ';
  67                         sig_hex += format("%02X", static_cast<unsigned char>(sig_buf[i]));
  68                 }
  69                 throw unsupported_image_format(sig_hex);
  70         }
  71
  72         return loader;
  73 }
  74
  75
  76 ImageLoader::RegisterBase::RegisterBase()
  77 {
  78         get_registered_loaders().push_back(this);
  79         registered_loaders_changed = true;
  80 }
  81
  82
  83 list<ImageLoader::RegisterBase *> &ImageLoader::get_registered_loaders()
  84 {
  85         static list<RegisterBase *> regs;
  86         return regs;
  87 }
  88
  89 bool ImageLoader::signature_size_compare(RegisterBase *r1, RegisterBase *r2)
  90 {
  91         return r1->get_signature_size()<r2->get_signature_size();
  92 }
  93
  94 } // namespace Graphics
  95 } // namespace Msp