Emilia Marino / SDFileSystem

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

FATFileSystem/MemFileSystem.h@0:5f7b02d095c2, 2021-12-18 (annotated)

Committer:
emiliamarino
Date:
Sat Dec 18 20:17:31 2021 +0000
Revision:
0:5f7b02d095c2
Assignment 4

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emiliamarino 0:5f7b02d095c2 1 /* mbed Microcontroller Library - MemFileSystem
emiliamarino 0:5f7b02d095c2 2 * Copyright (c) 2008, sford
emiliamarino 0:5f7b02d095c2 3 */
emiliamarino 0:5f7b02d095c2 4
emiliamarino 0:5f7b02d095c2 5
emiliamarino 0:5f7b02d095c2 6 #ifndef MBED_MEMFILESYSTEM_H
emiliamarino 0:5f7b02d095c2 7 #define MBED_MEMFILESYSTEM_H
emiliamarino 0:5f7b02d095c2 8
emiliamarino 0:5f7b02d095c2 9 #include "FATFileSystem.h"
emiliamarino 0:5f7b02d095c2 10
emiliamarino 0:5f7b02d095c2 11 namespace mbed
emiliamarino 0:5f7b02d095c2 12 {
emiliamarino 0:5f7b02d095c2 13
emiliamarino 0:5f7b02d095c2 14 class MemFileSystem : public FATFileSystem
emiliamarino 0:5f7b02d095c2 15 {
emiliamarino 0:5f7b02d095c2 16 public:
emiliamarino 0:5f7b02d095c2 17
emiliamarino 0:5f7b02d095c2 18 // 2000 sectors, each 512 bytes (malloced as required)
emiliamarino 0:5f7b02d095c2 19 char *sectors[2000];
emiliamarino 0:5f7b02d095c2 20
emiliamarino 0:5f7b02d095c2 21 MemFileSystem(const char* name) : FATFileSystem(name) {
emiliamarino 0:5f7b02d095c2 22 memset(sectors, 0, sizeof(sectors));
emiliamarino 0:5f7b02d095c2 23 }
emiliamarino 0:5f7b02d095c2 24
emiliamarino 0:5f7b02d095c2 25 virtual ~MemFileSystem() {
emiliamarino 0:5f7b02d095c2 26 for(int i = 0; i < 2000; i++) {
emiliamarino 0:5f7b02d095c2 27 if(sectors[i]) {
emiliamarino 0:5f7b02d095c2 28 free(sectors[i]);
emiliamarino 0:5f7b02d095c2 29 }
emiliamarino 0:5f7b02d095c2 30 }
emiliamarino 0:5f7b02d095c2 31 }
emiliamarino 0:5f7b02d095c2 32
emiliamarino 0:5f7b02d095c2 33 // read a sector in to the buffer, return 0 if ok
emiliamarino 0:5f7b02d095c2 34 virtual int disk_read(char *buffer, int sector) {
emiliamarino 0:5f7b02d095c2 35 if(sectors[sector] == 0) {
emiliamarino 0:5f7b02d095c2 36 // nothing allocated means sector is empty
emiliamarino 0:5f7b02d095c2 37 memset(buffer, 0, 512);
emiliamarino 0:5f7b02d095c2 38 } else {
emiliamarino 0:5f7b02d095c2 39 memcpy(buffer, sectors[sector], 512);
emiliamarino 0:5f7b02d095c2 40 }
emiliamarino 0:5f7b02d095c2 41 return 0;
emiliamarino 0:5f7b02d095c2 42 }
emiliamarino 0:5f7b02d095c2 43
emiliamarino 0:5f7b02d095c2 44 // write a sector from the buffer, return 0 if ok
emiliamarino 0:5f7b02d095c2 45 virtual int disk_write(const char *buffer, int sector) {
emiliamarino 0:5f7b02d095c2 46 // if buffer is zero deallocate sector
emiliamarino 0:5f7b02d095c2 47 char zero[512];
emiliamarino 0:5f7b02d095c2 48 memset(zero, 0, 512);
emiliamarino 0:5f7b02d095c2 49 if(memcmp(zero, buffer, 512)==0) {
emiliamarino 0:5f7b02d095c2 50 if(sectors[sector] != 0) {
emiliamarino 0:5f7b02d095c2 51 free(sectors[sector]);
emiliamarino 0:5f7b02d095c2 52 sectors[sector] = 0;
emiliamarino 0:5f7b02d095c2 53 }
emiliamarino 0:5f7b02d095c2 54 return 0;
emiliamarino 0:5f7b02d095c2 55 }
emiliamarino 0:5f7b02d095c2 56 // else allocate a sector if needed, and write
emiliamarino 0:5f7b02d095c2 57 if(sectors[sector] == 0) {
emiliamarino 0:5f7b02d095c2 58 char *sec = (char*)malloc(512);
emiliamarino 0:5f7b02d095c2 59 if(sec==0) {
emiliamarino 0:5f7b02d095c2 60 return 1; // out of memory
emiliamarino 0:5f7b02d095c2 61 }
emiliamarino 0:5f7b02d095c2 62 sectors[sector] = sec;
emiliamarino 0:5f7b02d095c2 63 }
emiliamarino 0:5f7b02d095c2 64 memcpy(sectors[sector], buffer, 512);
emiliamarino 0:5f7b02d095c2 65 return 0;
emiliamarino 0:5f7b02d095c2 66 }
emiliamarino 0:5f7b02d095c2 67
emiliamarino 0:5f7b02d095c2 68 // return the number of sectors
emiliamarino 0:5f7b02d095c2 69 virtual int disk_sectors() {
emiliamarino 0:5f7b02d095c2 70 return sizeof(sectors)/sizeof(sectors[0]);
emiliamarino 0:5f7b02d095c2 71 }
emiliamarino 0:5f7b02d095c2 72
emiliamarino 0:5f7b02d095c2 73 };
emiliamarino 0:5f7b02d095c2 74
emiliamarino 0:5f7b02d095c2 75 }
emiliamarino 0:5f7b02d095c2 76
emiliamarino 0:5f7b02d095c2 77 #endif