ESP8266 Community Forum

- Tue Oct 06, 2015 9:31 am #30659 I've done a bit of searching, but came up short. And this time I'm really clueless...

I have "potentially" large struct array occupying like 1K+. This is too big for EEPROM, so I'm thinking that SPIFFS will work... My initial thoughts are to take a pointer to the array and write it out byte wise to SPIFFS.. then to try and re-create it back in memory again?

Does anyone know of, have any, or willing to provide examples of doing such things with the new SPIFFS api?

thanks in advance?

- Mon Oct 12, 2015 9:15 am #31166 Thought I'd answer my own question... and post another

To write a struct array to SPIFFS...

Code: Select all        long start_time_spiffs = millis();

      File configFile = SPIFFS.open("/lights.conf", "w+");
        
        if (!configFile)
           {
             Serial.println(F("Failed to open test.conf"));            
           } else {
           
              Serial.println(F("Opened Hue_conf.txt for UPDATE...."));
              Serial.printf("Start Position =%u \n", configFile.position());

              unsigned char * data = reinterpret_cast<unsigned char*>(Lights); // use unsigned char, as uint8_t is not guarunteed to be same width as char...
              size_t bytes = configFile.write(data, sizeof(HueLight) * _LightCount ); // C++ way

               Serial.printf("END Position =%u \n", configFile.position());
              configFile.close();

           }


to copy data back from SPIFFS file into a struct array

Code: Select allFile LightsFile = SPIFFS.open("/lights.conf", "r");
        
        if (!LightsFile)
           {
             Serial.println(F("Failed to open lights.conf"));
           } else {
              Serial.println(F("Opened lights.conf"));
              Serial.print(F("CONFIG FILE CONTENTS----------------------"));
              Serial.println();

              uint8_t light[sizeof(HueLight)];
              size_t size = LightsFile.size();
            uint8_t counter = 0;

            for(int i=0; i<size; i+=sizeof(HueLight)){
              
                 for(int j=0;j<sizeof(HueLight);j++){
                   light[j] = LightsFile.read();
                 }
              
              HueLight *thelight = (HueLight *)light;
             HueLight *currentlight = &Lights[counter];
             memcpy (currentlight , thelight , sizeof(HueLight));

              Serial.printf( "Saved Light:%3u, %15s, State = %u, HSB(%5u,%3u,%3u) \n",
               counter, thelight->Name, thelight->State, thelight->Hue, thelight->Sat, thelight->Bri);
            
            counter++;
            }

              LightsFile.close();
           }


- Sat Dec 01, 2018 5:43 pm #79360

Thought I'd answer my own question... and post another

To write a struct array to SPIFFS...

Code: Select all        long start_time_spiffs = millis();

      File configFile = SPIFFS.open("/lights.conf", "w+");
        
        if (!configFile)
           {
             Serial.println(F("Failed to open test.conf"));            
           } else {
           
              Serial.println(F("Opened Hue_conf.txt for UPDATE...."));
              Serial.printf("Start Position =%u \n", configFile.position());

              unsigned char * data = reinterpret_cast<unsigned char*>(Lights); // use unsigned char, as uint8_t is not guarunteed to be same width as char...
              size_t bytes = configFile.write(data, sizeof(HueLight) * _LightCount ); // C++ way

               Serial.printf("END Position =%u \n", configFile.position());
              configFile.close();

           }


to copy data back from SPIFFS file into a struct array

Code: Select allFile LightsFile = SPIFFS.open("/lights.conf", "r");
        
        if (!LightsFile)
           {
             Serial.println(F("Failed to open lights.conf"));
           } else {
              Serial.println(F("Opened lights.conf"));
              Serial.print(F("CONFIG FILE CONTENTS----------------------"));
              Serial.println();

              uint8_t light[sizeof(HueLight)];
              size_t size = LightsFile.size();
            uint8_t counter = 0;

            for(int i=0; i<size; i+=sizeof(HueLight)){
              
                 for(int j=0;j<sizeof(HueLight);j++){
                   light[j] = LightsFile.read();
                 }
              
              HueLight *thelight = (HueLight *)light;
             HueLight *currentlight = &Lights[counter];
             memcpy (currentlight , thelight , sizeof(HueLight));

              Serial.printf( "Saved Light:%3u, %15s, State = %u, HSB(%5u,%3u,%3u) \n",
               counter, thelight->Name, thelight->State, thelight->Hue, thelight->Sat, thelight->Bri);
            
            counter++;
            }

              LightsFile.close();
           }


Hi there ..

Would you possibly have a little clearer example ?

Anyone else please ?

D