Diff: SDFileSystem/FATFileSystem/MemFileSystem.h

Revision:

0:aa13e1c335cd

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SDFileSystem/FATFileSystem/MemFileSystem.h	Sun Nov 04 18:44:51 2018 -0700
@@ -0,0 +1,77 @@
+/* mbed Microcontroller Library - MemFileSystem
+ * Copyright (c) 2008, sford
+ */
+
+
+#ifndef MBED_MEMFILESYSTEM_H
+#define MBED_MEMFILESYSTEM_H
+
+#include "FATFileSystem.h"
+
+namespace mbed
+{
+
+    class MemFileSystem : public FATFileSystem
+    {
+    public:
+    
+        // 2000 sectors, each 512 bytes (malloced as required)
+        char *sectors[2000];
+    
+        MemFileSystem(const char* name) : FATFileSystem(name) {
+            memset(sectors, 0, sizeof(sectors));
+        }
+    
+        virtual ~MemFileSystem() {
+            for(int i = 0; i < 2000; i++) {
+                if(sectors[i]) {
+                    free(sectors[i]);
+                }
+            }
+        }
+    
+        // read a sector in to the buffer, return 0 if ok
+        virtual int disk_read(char *buffer, int sector) {
+            if(sectors[sector] == 0) {
+                // nothing allocated means sector is empty
+                memset(buffer, 0, 512);
+            } else {
+                memcpy(buffer, sectors[sector], 512);
+            }
+            return 0;
+        }
+    
+        // write a sector from the buffer, return 0 if ok
+        virtual int disk_write(const char *buffer, int sector) {
+            // if buffer is zero deallocate sector
+            char zero[512];
+            memset(zero, 0, 512);
+            if(memcmp(zero, buffer, 512)==0) {
+                if(sectors[sector] != 0) {
+                    free(sectors[sector]);
+                    sectors[sector] = 0;
+                }
+                return 0;
+            }
+            // else allocate a sector if needed, and write
+            if(sectors[sector] == 0) {
+                char *sec = (char*)malloc(512);
+                if(sec==0) {
+                    return 1; // out of memory
+                }
+                sectors[sector] = sec;
+            }
+            memcpy(sectors[sector], buffer, 512);
+            return 0;
+        }
+    
+        // return the number of sectors
+        virtual int disk_sectors() {
+            return sizeof(sectors)/sizeof(sectors[0]);
+        }
+    
+    };
+
+}
+
+#endif
\ No newline at end of file