Add a function to detect image signature without creating a loader

[libs/gui.git] / source / graphics / imageloader.cpp

diff --git a/source/graphics/imageloader.cpp b/source/graphics/imageloader.cpp
index e224af63cd161495a7e13a7ee795c92273864678..859a34c12894a1a0460b439e230a0fe9154d1385 100644 (file)
--- a/source/graphics/imageloader.cpp
+++ b/source/graphics/imageloader.cpp
@@ -32,6 +32,15 @@ ImageLoader::~ImageLoader()
        delete source;
 }
 
+bool ImageLoader::detect_signature(const std::string &sig)
+{
+       Registry &registry = get_registry();
+       for(list<RegisterBase *>::const_iterator i=registry.loaders.begin(); i!=registry.loaders.end(); ++i)
+               if((*i)->detect(sig))
+                       return true;
+       return false;
+}
+
 ImageLoader *ImageLoader::open_file(const string &fn)
 {
        try
@@ -59,9 +68,8 @@ ImageLoader *ImageLoader::open_io(IO::Seekable &io)
        if(registry.loaders.empty())
                throw unsupported_image_format("no loaders");
 
-       vector<char> sig_buf(registry.loaders.back()->get_signature_size());
-       unsigned sig_len = io.read(&sig_buf[0], sig_buf.size());
-       string signature(sig_buf.begin(), sig_buf.end());
+       string signature(registry.loaders.back()->get_signature_size(), 0);
+       unsigned sig_len = io.read(&signature[0], signature.size());
 
        ImageLoader *loader = 0;
        for(list<RegisterBase *>::const_iterator i=registry.loaders.begin(); (!loader && i!=registry.loaders.end()); ++i)
@@ -74,7 +82,7 @@ ImageLoader *ImageLoader::open_io(IO::Seekable &io)
        {
                string sig_hex;
                for(unsigned i=0; i<sig_len; ++i)
-                       append(sig_hex, " ", format("%02X", static_cast<unsigned char>(sig_buf[i])));
+                       append(sig_hex, " ", format("%02X", static_cast<unsigned char>(signature[i])));
                throw unsupported_image_format(sig_hex);
        }