vendor: Add dependencies for discosrv

vendor/github.com/cznic/mathutil/ff/main.go

@@ -0,0 +1,83 @@
+// Copyright (c) jnml. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore
+
+// Factor Finder - searches for Mersenne number factors of one specific special
+// form.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"math/big"
+	"runtime"
+	"time"
+
+	"github.com/cznic/mathutil"
+)
+
+const (
+	pp  = 1
+	pp2 = 10
+)
+
+var (
+	_1 = big.NewInt(1)
+	_2 = big.NewInt(2)
+)
+
+func main() {
+	runtime.GOMAXPROCS(2)
+	oClass := flag.Uint64("c", 2, `factor "class" number`)
+	oDuration := flag.Duration("d", time.Second, "duration to spend on one class")
+	flag.Parse()
+	class := *oClass
+	for class&1 != 0 {
+		class >>= 1
+	}
+	class = mathutil.MaxUint64(class, 2)
+
+	for {
+		c := time.After(*oDuration)
+		factor := big.NewInt(0)
+		factor.SetUint64(class)
+		exp := big.NewInt(0)
+	oneClass:
+		for {
+			select {
+			case <-c:
+				break oneClass
+			default:
+			}
+
+			exp.Set(factor)
+			factor.Lsh(factor, 1)
+			factor.Add(factor, _1)
+			if !factor.ProbablyPrime(pp) {
+				continue
+			}
+
+			if !exp.ProbablyPrime(pp) {
+				continue
+			}
+
+			if mathutil.ModPowBigInt(_2, exp, factor).Cmp(_1) != 0 {
+				continue
+			}
+
+			if !factor.ProbablyPrime(pp2) {
+				continue
+			}
+
+			if !exp.ProbablyPrime(pp2) {
+				continue
+			}
+
+			fmt.Printf("%d: %s | M%s (%d bits)\n", class, factor, exp, factor.BitLen())
+		}
+
+		class += 2
+	}
+}