Improve help information.

indivisible.1

@@ -6,7 +6,9 @@ indivisible \- prime number generator and tester
 [\fIOPTIONS\fR] <\fIn\fR>
 
 .SH "DESCRIPTION"
-Indivisible is a program for working with prime numbers. Its default behaviour will attempt to find the \fInth\fR prime.
+Indivisible is a program for working with prime numbers. It can either generate
+primes up to a limit \fIn\fR or test to see if \fIn\fR is a prime. It makes use
+of a segmented sieve of Eratosthenes.
 
 .SH "OPTIONS"
 .TP
@@ -19,6 +21,9 @@ Import prime numbers from \fIFILE\fR
 \fB\-t\fR, \fB\-\-test\fR
 Test if n is a prime instead of generation
 .TP
+\fB\-s\fR, \fB\-\-sieve\fR <\fISIZE\fR>
+Set a custom sieve size
+.TP
 \fB\-v\fR, \fB\-\-verbose\fR
 Print all found primes
 .TP

src/main.rs

@@ -35,12 +35,12 @@ struct Opt {
 	test:bool,
 	#[structopt(help = "Max of the prime to generate or number to test for primality")]
 	num:usize,
+	#[structopt(short, long, name = "SIZE", default_value = "1000", help = "Set a custom sieve size")]
+	sieve:usize,
 	//#[structopt(short, long, name = "n", default_value = "1", help = "Number of threads to spawn")]
 	//jobs:u64,
 }
 
-const SEGMENT_SIZE:usize = 0x100000000;
-
 fn main() {
 	let opts = Opt::from_args();
 	let mut prime_list = Vec::new();
@@ -49,7 +49,12 @@ fn main() {
 		let in_file = File::open(opts.import.unwrap()).unwrap();
 		let reader = BufReader::new(in_file);
 		for p in reader.lines().into_iter() {
-			prime_list.push(p.unwrap().parse().unwrap());
+			let prime:u64 = p.unwrap().parse().unwrap();
+			if (prime as usize) > opts.num {
+				break;
+			}
+
+			prime_list.push(prime);
 		}
 	}
 
@@ -61,11 +66,11 @@ fn main() {
 	let mut start:usize = if prime_list.is_empty() {
 		2
 	} else {
-		*prime_list.last().unwrap() as usize
+		(*prime_list.last().unwrap() + 1) as usize
 	};
 	while start < opts.num {
-		let end = if start + SEGMENT_SIZE < opts.num {
-			start + SEGMENT_SIZE
+		let end = if start + opts.sieve < opts.num {
+			start + opts.sieve
 		} else {
 			opts.num + 1
 		};
@@ -78,7 +83,7 @@ fn main() {
 		}
 		prime_list.append(&mut new_primes);
 
-		start += SEGMENT_SIZE;
+		start += opts.sieve;
 	}
 
 	if opts.test {

test.sh

@@ -17,9 +17,12 @@ fi
 tests=0
 passed=0
 
+## TEST 1
 ((tests++))
-echo -n "${tests}: Find 5th prime number..."
-if [[ $("$BINARY" 5) == 11 ]]
+echo -n "${tests}: Find all prime numbers before 70..."
+expect="2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 "
+
+if [ "$("$BINARY" -v 70 | tr '\n' ' ')" = "$expect" ]
 then
 	echo " pass"
 	((passed++))
@@ -27,6 +30,7 @@ else
 	echo " FAIL"
 fi
 
+## TEST 2
 ((tests++))
 echo -n "${tests}: 11 is prime..."
 if "$BINARY" -t 11
@@ -37,6 +41,7 @@ else
 	echo " FAIL"
 fi
 
+## TEST 3
 ((tests++))
 echo -n "${tests}: 9 is not prime..."
 if ! "$BINARY" -t 9
@@ -47,4 +52,5 @@ else
 	echo " FAIL"
 fi
 
+## RESULTS
 echo "Results: $passed/$tests"