speed up un-cached directories

embedded thumbnails will be used for the first pass when cached thumbnails are not found.

rtengine/imageio.cc

@@ -259,6 +259,75 @@ int ImageIO::loadPNG  (Glib::ustring fname) {
 
 extern jmp_buf jpeg_jmp_buf;
 
+extern "C" {
+void jpeg_memory_src (jpeg_decompress_struct* cinfo, const char* buffer, int bufsize);
+}
+
+int ImageIO::loadJPEGFromMemory (const char* buffer, int bufsize)
+{
+    jpeg_decompress_struct cinfo;
+    jpeg_error_mgr jerr;
+    cinfo.err = my_jpeg_std_error(&jerr);
+    jpeg_create_decompress(&cinfo);
+    jpeg_memory_src (&cinfo,buffer,bufsize);
+
+    if (pl) {
+      pl->setProgressStr ("Loading JPEG file...");
+      pl->setProgress (0.0);
+
+    }
+
+    setup_read_icc_profile (&cinfo);
+
+    if (!setjmp(jpeg_jmp_buf)) {
+	jpeg_memory_src (&cinfo,buffer,bufsize);
+    	jpeg_read_header(&cinfo, TRUE);
+
+        unsigned int proflen;    	
+        delete loadedProfileData;
+        loadedProfileData = NULL;
+        bool hasprofile = read_icc_profile (&cinfo, (JOCTET**)&loadedProfileData, (unsigned int*)&loadedProfileLength);
+    	if (hasprofile) 
+    	    embProfile = cmsOpenProfileFromMem (loadedProfileData, loadedProfileLength);
+    	else 
+            embProfile = NULL;
+    	
+	    jpeg_start_decompress(&cinfo);
+
+        int width = cinfo.output_width;
+        int height = cinfo.output_height;
+
+        allocate (width, height);
+
+	    unsigned char *row=new unsigned char[width*3];
+	    while (cinfo.output_scanline < height) {
+		    if (jpeg_read_scanlines(&cinfo,&row,1) < 1) {
+  	          jpeg_finish_decompress(&cinfo);
+ 	          jpeg_destroy_decompress(&cinfo);
+ 	          delete [] row;
+              return IMIO_READERROR;
+            }
+            setScanline (cinfo.output_scanline-1, row, 8);
+
+            if (pl && !(cinfo.output_scanline%100))
+              pl->setProgress ((double)(cinfo.output_scanline)/cinfo.output_height);
+	    }
+	    delete [] row;
+
+	    jpeg_finish_decompress(&cinfo);
+	    jpeg_destroy_decompress(&cinfo);
+        if (pl) {
+          pl->setProgressStr ("Ready.");
+          pl->setProgress (1.0);
+        }
+        return IMIO_SUCCESS;
+    }
+    else {
+        jpeg_destroy_decompress(&cinfo);
+        return IMIO_READERROR;
+    }
+}
+
 int ImageIO::loadJPEG (Glib::ustring fname) {
 
 	FILE *file=g_fopen(fname.c_str(),"rb");