/* TFS468 A storage utility based on TinyFS 
 * Foaad Khosmood  / Spring 2016
 * California Polytechnic State University */

#define DEBUG_STATE 1
#define DEBUG(text) if (DEBUG_STATE) {fprintf(stderr,"DEBUG:: "); fprintf(stderr,text); \
                fprintf(stderr, "\n");}

/*		fprintf(stderr, "\tFile : \"%s\"\tFunction : \"%s\"\t"\
                "Line : %d\n", __FILE__, __func__, __LINE__);} 
*/

#define MAX_DISKS 100
#define DISK_NAME_SIZE 20

typedef struct Disk {
   int enabled;
   int blocks;
   char name[DISK_NAME_SIZE];
} Disk;

//Disk disks[MAX_DISKS];

/* This functions opens a regular UNIX file and designates the first nBytes of
 * it as space for the emulated disk. nBytes should be an integral number of
 * the block size. If nBytes > 0 and there is already a file by the given
 * filename, that file's content may be overwritten. If nBytes is 0, an
 * existing disk is opened, and should not be overwritten. There is no
 * requirement to maintain integrity of any file content beyond nBytes.
 * The return value is -1 on failure or a disk number on success. */
int openDisk(char *filename, int nBytes);

/* readBlock() reads an entire block of BLOCKSIZE bytes from the open disk
 * (identified by 'disk') and copies the result into a local buffer (must be at
 * least of BLOCKSIZE bytes). The bNum is a logical block number, which must be
 * translated into a byte offset within the disk. The translation from logical
 * to physical block is straightforward: bNum=0 is the very first byte of the
 * file. bNum=1 is BLOCKSIZE bytes into the disk, bNum=n is n*BLOCKSIZE bytes
 * into the disk. On success, it returns 0. -1 or smaller is returned if disk
 * is not available (hasn't been opened) or any other failures.
 * You must define your own error code system. */
int readBlock(int disk, int bNum, void *block);

/* writeBlock() takes disk number 'disk' and logical block number 'bNum' and
 * writes the content of the buffer 'block' to that location. 'block' must be
 * integral with BLOCKSIZE. Just as in readBlock(), writeBlock() must translate
 * the logical block bNum to the correct byte position in the file. On success,
 * it returns 0. -1 or smaller is returned if disk is not available (i.e.
 * hasn't been opened) or any other failures.
 * You must define your own error code system. */
int writeBlock(int disk, int bNum, void *block);