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This aim of this project is to create a small program able to read FAT16 image on Linux. This project has also been ported to a PIC24, seeBoatController.The data folder contains images used to test the program.

The driver can:

• list files in a directory
• read to a file (a file can be opened several times in reading mode)
• write to a file: any previous contents are erased. A file cannot be read while it is opened in write mode.
• append to a file: similar to write mode but any previous content is preserved and writing happen at the end.
• create/delete directories

This driver cannot handle long names.

Names of files and directories must respect the format described here:https://en.wikipedia.org/wiki/8.3_filename. Hence, all valid names can be stored as an array of char of length 13 characters (12 bytes for the filename and one byte for the null character).

make

This creates a shared librarylibfat16_driver.so in thelib folder.The test suite must be run as root:

sudo ./bin/run_test

You will need to implement the following functions to construct astruct storage_dev_t:

int (*read)(void*buffer,uint32_tlength);int (*read_byte)(void*data);int (*write)(constvoid*buffer,uint32_tlength);int (*seek)(uint32_toffset);

You will also need to find out where the fat16 partition starts. If it is a FAT16 image, the address is most likely 0. Otherwise, read the MBR to get the first sector of a FAT16 partition, multiplied by 512 (bytes per sector) and pass it tofat16_init.

On some compilers such as Microchip XC16, some features from C99 such as printinguint32_t are not supportedso you may have to change the format in debug print.

Printing content of a file:

voidprint_file_content(void){intfd=fat16_open("DATA.TXT",'r');if (fd<0) {fprintf(stderr,"Failed to read DATA.TXT\n");return;    }while (1) {charbuffer[256];inti,n;n=fat16_read(fd,buffer,sizeof(buffer));if (n==0) {/* End of file reached */break;        }elseif (n<0) {fprintf(stderr,"Error %d while reading\n",-n);break;        }else {for (i=0;i<n;++i)printf("%c",buffer[i]);        }    }fat16_close(fd);}

Listing files in root directory:

voidlist_files(void){charfilename[13];uint32_ti=0;while(fat16_ls(&i,filename,"/")==1) {printf("%s\n",filename);    }}