Alek Boving / SDFileSystem8

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FATFileSystem/MemFileSystem.h@0:83e8ad3d9a65, 2020-11-12 (annotated)

Committer:
alekboving
Date:
Thu Nov 12 15:20:15 2020 +0000
Revision:
0:83e8ad3d9a65
initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
alekboving 0:83e8ad3d9a65 1 /* mbed Microcontroller Library - MemFileSystem
alekboving 0:83e8ad3d9a65 2 * Copyright (c) 2008, sford
alekboving 0:83e8ad3d9a65 3 */
alekboving 0:83e8ad3d9a65 4
alekboving 0:83e8ad3d9a65 5
alekboving 0:83e8ad3d9a65 6 #ifndef MBED_MEMFILESYSTEM_H
alekboving 0:83e8ad3d9a65 7 #define MBED_MEMFILESYSTEM_H
alekboving 0:83e8ad3d9a65 8
alekboving 0:83e8ad3d9a65 9 #include "FATFileSystem.h"
alekboving 0:83e8ad3d9a65 10
alekboving 0:83e8ad3d9a65 11 namespace mbed
alekboving 0:83e8ad3d9a65 12 {
alekboving 0:83e8ad3d9a65 13
alekboving 0:83e8ad3d9a65 14 class MemFileSystem : public FATFileSystem
alekboving 0:83e8ad3d9a65 15 {
alekboving 0:83e8ad3d9a65 16 public:
alekboving 0:83e8ad3d9a65 17
alekboving 0:83e8ad3d9a65 18 // 2000 sectors, each 512 bytes (malloced as required)
alekboving 0:83e8ad3d9a65 19 char *sectors[2000];
alekboving 0:83e8ad3d9a65 20
alekboving 0:83e8ad3d9a65 21 MemFileSystem(const char* name) : FATFileSystem(name) {
alekboving 0:83e8ad3d9a65 22 memset(sectors, 0, sizeof(sectors));
alekboving 0:83e8ad3d9a65 23 }
alekboving 0:83e8ad3d9a65 24
alekboving 0:83e8ad3d9a65 25 virtual ~MemFileSystem() {
alekboving 0:83e8ad3d9a65 26 for(int i = 0; i < 2000; i++) {
alekboving 0:83e8ad3d9a65 27 if(sectors[i]) {
alekboving 0:83e8ad3d9a65 28 free(sectors[i]);
alekboving 0:83e8ad3d9a65 29 }
alekboving 0:83e8ad3d9a65 30 }
alekboving 0:83e8ad3d9a65 31 }
alekboving 0:83e8ad3d9a65 32
alekboving 0:83e8ad3d9a65 33 // read a sector in to the buffer, return 0 if ok
alekboving 0:83e8ad3d9a65 34 virtual int disk_read(char *buffer, int sector) {
alekboving 0:83e8ad3d9a65 35 if(sectors[sector] == 0) {
alekboving 0:83e8ad3d9a65 36 // nothing allocated means sector is empty
alekboving 0:83e8ad3d9a65 37 memset(buffer, 0, 512);
alekboving 0:83e8ad3d9a65 38 } else {
alekboving 0:83e8ad3d9a65 39 memcpy(buffer, sectors[sector], 512);
alekboving 0:83e8ad3d9a65 40 }
alekboving 0:83e8ad3d9a65 41 return 0;
alekboving 0:83e8ad3d9a65 42 }
alekboving 0:83e8ad3d9a65 43
alekboving 0:83e8ad3d9a65 44 // write a sector from the buffer, return 0 if ok
alekboving 0:83e8ad3d9a65 45 virtual int disk_write(const char *buffer, int sector) {
alekboving 0:83e8ad3d9a65 46 // if buffer is zero deallocate sector
alekboving 0:83e8ad3d9a65 47 char zero[512];
alekboving 0:83e8ad3d9a65 48 memset(zero, 0, 512);
alekboving 0:83e8ad3d9a65 49 if(memcmp(zero, buffer, 512)==0) {
alekboving 0:83e8ad3d9a65 50 if(sectors[sector] != 0) {
alekboving 0:83e8ad3d9a65 51 free(sectors[sector]);
alekboving 0:83e8ad3d9a65 52 sectors[sector] = 0;
alekboving 0:83e8ad3d9a65 53 }
alekboving 0:83e8ad3d9a65 54 return 0;
alekboving 0:83e8ad3d9a65 55 }
alekboving 0:83e8ad3d9a65 56 // else allocate a sector if needed, and write
alekboving 0:83e8ad3d9a65 57 if(sectors[sector] == 0) {
alekboving 0:83e8ad3d9a65 58 char *sec = (char*)malloc(512);
alekboving 0:83e8ad3d9a65 59 if(sec==0) {
alekboving 0:83e8ad3d9a65 60 return 1; // out of memory
alekboving 0:83e8ad3d9a65 61 }
alekboving 0:83e8ad3d9a65 62 sectors[sector] = sec;
alekboving 0:83e8ad3d9a65 63 }
alekboving 0:83e8ad3d9a65 64 memcpy(sectors[sector], buffer, 512);
alekboving 0:83e8ad3d9a65 65 return 0;
alekboving 0:83e8ad3d9a65 66 }
alekboving 0:83e8ad3d9a65 67
alekboving 0:83e8ad3d9a65 68 // return the number of sectors
alekboving 0:83e8ad3d9a65 69 virtual int disk_sectors() {
alekboving 0:83e8ad3d9a65 70 return sizeof(sectors)/sizeof(sectors[0]);
alekboving 0:83e8ad3d9a65 71 }
alekboving 0:83e8ad3d9a65 72
alekboving 0:83e8ad3d9a65 73 };
alekboving 0:83e8ad3d9a65 74
alekboving 0:83e8ad3d9a65 75 }
alekboving 0:83e8ad3d9a65 76
alekboving 0:83e8ad3d9a65 77 #endif