AP_FlashStorage: added re_initialise() API

libraries/AP_FlashStorage/AP_FlashStorage.cpp

@@ -277,9 +277,7 @@ bool AP_FlashStorage::erase_sector(uint8_t sector)
 bool AP_FlashStorage::erase_all(void)
 {
     write_error = false;
-    
-    // start with empty memory buffer
-    memset(mem_buffer, 0, storage_size);
+
     current_sector = 0;
     write_offset = sizeof(struct sector_header);
     
@@ -374,3 +372,17 @@ bool AP_FlashStorage::switch_sectors(void)
     write_offset = sizeof(header);
     return true;    
 }
+
+/*
+  re-initialise, using current mem_buffer
+ */
+bool AP_FlashStorage::re_initialise(void)
+{
+    if (!flash_erase_ok()) {
+        return false;
+    }
+    if (!erase_all()) {
+        return false;        
+    }
+    return write_all();
+}

libraries/AP_FlashStorage/AP_FlashStorage.h

@@ -72,6 +72,9 @@ public:
     // initialise storage, filling mem_buffer with current contents
     bool init(void);
 
+    // re-initialise storage, using current mem_buffer
+    bool re_initialise(void);
+    
     // switch full sector - should only be called when safe to have CPU
     // offline for considerable periods as an erase will be needed
     bool switch_full_sector(void);
@@ -135,7 +138,7 @@ private:
     bool erase_sector(uint8_t sector);
 
     // erase all sectors and reset
-    bool erase_all(void);
+    bool erase_all();
 
     // write all of mem_buffer to current sector
     bool write_all(void);