/* Input: An empty queue, and an initialized sudoku s, an empty queue
* for the solutions, and a pointer to a variable to store the
* number of guesses
* Returns: NULL if no possible solutions exist or the queue is not
* empty, and otherwise the solution to the input puzzle.
* -----------------------------------------------------------
* Solves the puzzle using backtracking. The solver is initialized by
* putting the puzzle into the empty queue. Then, each iteration will
* pull a board out of the queue, perform a simple reduction on that
* board, and then make a guess on the cell which has the least number
* of possibilities. If verbose is set, it prints each board before
* making a guess, giving a sense of the whole solution process.
*
* If there is nothing to pull out of the queue, there are no possible
* solutions to the puzzle, and the function returns an error value of
* NULL. If the queue is not empty at initialization, the function
* prints an error message regardless of the state of the flags, and
* returns an error.
*/
sudoku solve(queue q, sudoku s, int * guesses)
{
if (!isEmptyQueue(q)) {
printf("Error: call to solve with a non-empty queue");
return NULL;
}
putQueue(q, (void *) s);
*guesses = 0;
int slvd = 0;
while (1)
{
if (getQueue(q, (void **) &s)){
return NULL;
}
reduce(s);
if(verbose) {
system("clear");
printSudoku(s, pretty);
printf("\n");
}
slvd = checkSudoku(s);
if (slvd == -1) deleteSudoku(s);
else if (slvd == 1) return s;
else
{
if(guess(q, s)) {
printf("Error: Full queue");
return NULL;
}
deleteSudoku(s);
(*guesses)++;
}
}
}
void uart_recv_state(unsigned char byte) {
switch (uc_ptr->state) {
case UART_STATE_HEADER1:
if ( byte == UART_HEADER1) {
// WriteUSART(0x01);
uc_ptr->state = UART_STATE_HEADER2;
}
break;
case UART_STATE_HEADER2:
if ( byte == UART_HEADER2 ) {
//WriteUSART(0x02);
#if defined (ARM_PIC)
uc_ptr->state = UART_STATE_COUNT;
#elif defined (MAIN_PIC)
uc_ptr->state = UART_STATE_MSGTYPE;
#endif
}
else {
uc_ptr->state = UART_STATE_HEADER1;
}
break;
case UART_STATE_MSGTYPE:
uc_ptr->buflen = 0;
uc_ptr->data_read = 0;
// WriteUSART(0x03);
uc_ptr->msgtype = byte;
uc_ptr->buffer[0] = byte;
uc_ptr->state = UART_STATE_COUNT;
break;
case UART_STATE_COUNT:
// WriteUSART(0x04);
uc_ptr->count = byte;
#if defined (ARM_PIC)
uc_ptr->state = UART_STATE_LENGTH;
uc_ptr->buffer[0] = byte;
#elif defined (MAIN_PIC)
uc_ptr->buffer[1] = byte;
uc_ptr->state = UART_STATE_FOOTER;
#endif
break;
case UART_STATE_LENGTH:
// WriteUSART(0x05);
uc_ptr->buffer[1] = byte;
uc_ptr->data_length = byte;
uc_ptr->buflen = 0;
uc_ptr->data_read = 0;
uc_ptr->state = UART_STATE_DATA;
break;
case UART_STATE_DATA:
// WriteUSART(0x06);
// Store the byte into buffer
if ( uc_ptr->data_read + 2 < MAXUARTBUF ) {
uc_ptr->buffer[uc_ptr->data_read+2] = byte;
}
// Increment because we read 1 more byte
uc_ptr->data_read += 1;
// Keep reading data until, 9 BYTES for now
if(UARTDATALEN == uc_ptr->data_read) {
uc_ptr->state = UART_STATE_FOOTER;
}
break;
case UART_STATE_FOOTER:
// WriteUSART(0x07);
if ( byte == UART_FOOTER ) {
// WriteUSART(0x08);
uc_ptr->state = UART_STATE_HEADER1;
//LATBbits.LATB7 = !LATBbits.LATB7;
#if defined (ARM_PIC)
// Copy over into a buffer before passing
unsigned char temp[I2CMSGLEN];
int i;
for (i = 0; i < I2CMSGLEN; i++) {
temp[i] = uc_ptr->buffer[i];
}
LATB = 7; // Sequence 7
LATAbits.LA0 = 0;
// Put it in the roverDataBuf
ToMainLow_sendmsg(I2CMSGLEN, MSGT_BUF_PUT_DATA, (void *) temp);
#elif defined (MAIN_PIC)
// Wait for first to finish
LATBbits.LATB0 = 1;
LATBbits.LATB1 = 0;
LATBbits.LATB2 = 0; // Sequence 1
LATAbits.LA0 = 0;
i2c_master_cmd message;
message.msgType = uc_ptr->buffer[0];
message.msgCount = uc_ptr->buffer[1];
//if ( i2c_master_busy() == 0 )
// Put the message in the queue
while(i2c_master_busy());
putQueue(&i2c_q,message);
//ToMainLow_sendmsg(2, MSGT_BUF_PUT_DATA, (void *) uc_ptr->buffer);
#endif
}
else {
uc_ptr->state = UART_STATE_HEADER1;
}
uc_ptr->buflen = 0;
uc_ptr->data_read = 0;
break;
default:
break;
}
}
