Question

Below the map ‘widgets’ is always size of 1 for some reason. There should be 4 when it’s done.

Output:

Widget: widget_ram_label:layout_bar:0 1
Widget: widget_ram_active:layout_bar:0 1
Widget: widget_ram_total:layout_bar:0 1
Widget: widget_wlan0_label:layout_bar:0 1

Here’s widgets:

std::map<const char *, Widget *> widgets;

And here’s the code:

void Generic::BuildLayouts() {
   for(std::map<const char*, std::vector<widget_template> >::iterator l = 
       widget_templates.begin(); l != widget_templates.end(); l++) {
       std::vector<widget_template> layout = l->second;
       for(unsigned int i = 0; i < layout.size(); i++ ) {
           Json::Value *widget_v = CFG_Fetch_Raw(root, layout[i].key);
           if(!widget_v) {
               error("No widget named <%s>", layout[i].key);
               continue;
           }
           Json::Value *type = CFG_Fetch_Raw(widget_v, "type");
           if(!type) {
               error("Widget <%s> has no type!", layout[i].key);
               delete widget_v;
               continue;
           }

           Widget *widget;

           char name[256];
           sprintf(name, "%s:%s", layout[i].key, l->first);
           char tmp[256];
           int i = 0;
           sprintf(tmp, "%s:%d", name, i);

           while(widgets.find(tmp) != widgets.end()) {
               i++;
               sprintf(tmp, "%s:%d", name, i);
           }
           memcpy(name, tmp, 256);

           if(strcmp(type->asCString(), "text") == 0) {
               widget = (Widget *) new WidgetText(this, name, widget_v, 
                   layout[i].row, layout[i].col);
               std::cout << "Widget: " << name << " " << widgets.size() << std::endl;
           } else {
               error("Unknown widget type: %s", type->asCString());
           }
           if(widget) {
               widgets[name] = widget;
           }
           delete type;

       }
   }
}

Answer 1

Maybe because all your name pointers poitns to the same buffer? Because the content of name changes, but not the value of the pointer to name in the map.

Try to use std::string instead.

Replace you name buffer by

#include <string >
//...
std::string name = "the name";

and replace your map by

std::map< const std::string , Widget* > widgets;

That will make your life easier, safer and more readable.

To help formatting, use std::stringstream or boost string algorithms.

---

A start of example, this code :

                            char name[256];
            sprintf(name, "%s:%s", layout[i].key, l->first);
            char tmp[256];
            int i = 0;
            sprintf(tmp, "%s:%d", name, i);

            while(widgets.find(tmp) != widgets.end()) {
                i++;
                sprintf(tmp, "%s:%d", name, i);
            }
            memcpy(name, tmp, 256);

would be written like this:

Widget *widget = NULL; // always initialize your variables!!!

std::stringstream name_stream; // this will let us format our string
                name_stream << layout[i].key << ":" << l->first;

std::string name = name_stream.str(); // now we got the string formated.

std::stringstream tmp_stream; // same for tmp
tmp_stream << name << ":" << i; // will automatically convert basic types, see the doc if you want specific formatting

std::string tmp = tmp_stream.str(); // now we got the string formated.

// the while loop have no sense : a map have only one value by key
// if you want to have several values by key, use std::multi_map instead -- it don't work exactly the same though
// for now i'll just assume you just need to find the value associated to the name:


typedef std::map< const std::string, Widget* > WidgetMap; // for ease of writing, make a shortcut! ease your life!
WidgetMap::iterator tmp_it = widgets.find( tmp );

if( tmp_it != widgets.end() ) 
{   
// starting here I don't understand you code, so I'll let you find the rest :)
}