77 lines
2.0 KiB
C
77 lines
2.0 KiB
C
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/* mbed Microcontroller Library - MemFileSystem
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* Copyright (c) 2008, sford
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*/
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#ifndef MBED_MEMFILESYSTEM_H
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#define MBED_MEMFILESYSTEM_H
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#include "FATFileSystem.h"
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namespace mbed
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{
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class MemFileSystem : public FATFileSystem
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{
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public:
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// 2000 sectors, each 512 bytes (malloced as required)
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char *sectors[2000];
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MemFileSystem(const char* name) : FATFileSystem(name) {
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memset(sectors, 0, sizeof(sectors));
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}
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virtual ~MemFileSystem() {
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for(int i = 0; i < 2000; i++) {
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if(sectors[i]) {
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free(sectors[i]);
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}
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}
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}
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// read a sector in to the buffer, return 0 if ok
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virtual int disk_read(char *buffer, int sector) {
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if(sectors[sector] == 0) {
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// nothing allocated means sector is empty
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memset(buffer, 0, 512);
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} else {
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memcpy(buffer, sectors[sector], 512);
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}
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return 0;
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}
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// write a sector from the buffer, return 0 if ok
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virtual int disk_write(const char *buffer, int sector) {
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// if buffer is zero deallocate sector
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char zero[512];
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memset(zero, 0, 512);
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if(memcmp(zero, buffer, 512)==0) {
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if(sectors[sector] != 0) {
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free(sectors[sector]);
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sectors[sector] = 0;
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}
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return 0;
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}
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// else allocate a sector if needed, and write
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if(sectors[sector] == 0) {
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char *sec = (char*)malloc(512);
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if(sec==0) {
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return 1; // out of memory
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}
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sectors[sector] = sec;
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}
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memcpy(sectors[sector], buffer, 512);
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return 0;
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}
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// return the number of sectors
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virtual int disk_sectors() {
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return sizeof(sectors)/sizeof(sectors[0]);
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}
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};
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}
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#endif
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