sudoku-funpark/solver/flags.go

package solver

import (
	"flag"
	"fmt"
	"log"
	"os"
	"runtime"
)

func (solver *Solver) parse_flags() {

	// Define variables
	var row1 string
	var row2 string
	var row3 string
	var row4 string
	var row5 string
	var row6 string
	var row7 string
	var row8 string
	var row9 string

	// Define parameters
	flag.StringVar(&row1, "row1", "000000000", "1st row of the sudoku puzzle.")
	flag.StringVar(&row2, "row2", "000000000", "2nd row of the sudoku puzzle.")
	flag.StringVar(&row3, "row3", "000000000", "4rd row of the sudoku puzzle.")
	flag.StringVar(&row4, "row4", "000000000", "4th row of the sudoku puzzle.")
	flag.StringVar(&row5, "row5", "000000000", "5th row of the sudoku puzzle.")
	flag.StringVar(&row6, "row6", "000000000", "6th row of the sudoku puzzle.")
	flag.StringVar(&row7, "row7", "000000000", "7th row of the sudoku puzzle.")
	flag.StringVar(&row8, "row8", "000000000", "8th row of the sudoku puzzle.")
	flag.StringVar(&row9, "row9", "000000000", "9th row of the sudoku puzzle.")
	flag.IntVar(&solver.numcpus, "numcpu", runtime.NumCPU(), "Number of CPU cores to assign to this task.")

	// Parse the flags
	flag.Parse()

	if solver.numcpus <= 0 {
		log.Printf("ERROR: Number of CPU cores must be 1 or higher.\n\n")
		solver.print_Usage()
		os.Exit(1)
	}

	if solver.numcpus != runtime.NumCPU() {
		runtime.GOMAXPROCS(solver.numcpus)
	}

	if row1 == "000000000" || row2 == "000000000" || row3 == "000000000" || row4 == "000000000" || row5 == "000000000" || row6 == "000000000" || row7 == "000000000" || row8 == "000000000" || row9 == "000000000" {
		log.Printf("ERROR: All parameters must be entered.\n\n")
		solver.print_Usage()
		os.Exit(1)
	}

	// Validate the row (never trust user input)
	solver.validate_row("row1", row1)
	solver.validate_row("row2", row2)
	solver.validate_row("row3", row3)
	solver.validate_row("row4", row4)
	solver.validate_row("row5", row5)
	solver.validate_row("row6", row6)
	solver.validate_row("row7", row7)
	solver.validate_row("row8", row8)
	solver.validate_row("row9", row9)

	// Put entries in into the struct
	solver.row1 = row1
	solver.row2 = row2
	solver.row3 = row3
	solver.row4 = row4
	solver.row5 = row5
	solver.row6 = row6
	solver.row7 = row7
	solver.row8 = row8
	solver.row9 = row9

}

func (solver *Solver) validate_row(name string, row string) {

	var found bool
	var double bool
	count := make(map[rune]int)

	// 1. Make sure the row is 9 in length
	if len(row) != 9 {
		log.Printf("ERROR: Invalid length of %s (%s), must be 9 numbers\n\n", name, row)
		solver.print_Usage()
		os.Exit(1)
	}

	// 2. Ensure all digits are numbers
	for _, value := range row {
		found = solver.valid_char(value)
	}

	if !found {
		log.Printf("ERROR: Invalid character of %s (%s), must be 9 numbers\n\n", name, row)
		solver.print_Usage()
		os.Exit(1)
	}

	// 3. Ensure all digits (except zero) are there only once
	for _, digits := range row {
		count[digits] = count[digits] + 1
	}

	for key, value := range count {
		if value > 1 && key != 48 {
			double = true
		}
	}

	if double {
		log.Printf("ERROR: Double character of %s (%s), numbers between 1 and 9 may only be entered once\n\n", name, row)
		solver.print_Usage()
		os.Exit(1)
	}

}

func (solver *Solver) valid_char(char rune) bool {
	var valid bool
	decvals := [10]int{48, 49, 50, 51, 52, 53, 54, 55, 56, 57}

	for _, value := range decvals {
		if char == rune(value) {
			valid = true
		}
	}

	return valid
}

func (solver *Solver) print_Usage() {
	fmt.Fprintf(flag.CommandLine.Output(), "Usage of %s:\n", os.Args[0])
	fmt.Fprintf(flag.CommandLine.Output(), "\nPut every row of a Sudoku puzzle as paramters.\nUse '0' for what is currently blank in the puzzle you wish to solve.\n\n")
	fmt.Fprintf(flag.CommandLine.Output(), "Example: %s -row1 ... -row2 ... -row3 ... (etc)\n\n", os.Args[0])
	flag.PrintDefaults()
}