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/* 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
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