// Copyright 2009 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package big import ( "bytes" "encoding/gob" "encoding/hex" "encoding/json" "encoding/xml" "fmt" "math/rand" "testing" "testing/quick" ) func isNormalized(x *Int) bool { if len(x.abs) == 0 { return !x.neg } // len(x.abs) > 0 return x.abs[len(x.abs)-1] != 0 } type funZZ func(z, x, y *Int) *Int type argZZ struct { z, x, y *Int } var sumZZ = []argZZ{ {NewInt(0), NewInt(0), NewInt(0)}, {NewInt(1), NewInt(1), NewInt(0)}, {NewInt(1111111110), NewInt(123456789), NewInt(987654321)}, {NewInt(-1), NewInt(-1), NewInt(0)}, {NewInt(864197532), NewInt(-123456789), NewInt(987654321)}, {NewInt(-1111111110), NewInt(-123456789), NewInt(-987654321)}, } var prodZZ = []argZZ{ {NewInt(0), NewInt(0), NewInt(0)}, {NewInt(0), NewInt(1), NewInt(0)}, {NewInt(1), NewInt(1), NewInt(1)}, {NewInt(-991 * 991), NewInt(991), NewInt(-991)}, // TODO(gri) add larger products } func TestSignZ(t *testing.T) { var zero Int for _, a := range sumZZ { s := a.z.Sign() e := a.z.Cmp(&zero) if s != e { t.Errorf("got %d; want %d for z = %v", s, e, a.z) } } } func TestSetZ(t *testing.T) { for _, a := range sumZZ { var z Int z.Set(a.z) if !isNormalized(&z) { t.Errorf("%v is not normalized", z) } if (&z).Cmp(a.z) != 0 { t.Errorf("got z = %v; want %v", z, a.z) } } } func TestAbsZ(t *testing.T) { var zero Int for _, a := range sumZZ { var z Int z.Abs(a.z) var e Int e.Set(a.z) if e.Cmp(&zero) < 0 { e.Sub(&zero, &e) } if z.Cmp(&e) != 0 { t.Errorf("got z = %v; want %v", z, e) } } } func testFunZZ(t *testing.T, msg string, f funZZ, a argZZ) { var z Int f(&z, a.x, a.y) if !isNormalized(&z) { t.Errorf("%s%v is not normalized", msg, z) } if (&z).Cmp(a.z) != 0 { t.Errorf("%s%+v\n\tgot z = %v; want %v", msg, a, &z, a.z) } } func TestSumZZ(t *testing.T) { AddZZ := func(z, x, y *Int) *Int { return z.Add(x, y) } SubZZ := func(z, x, y *Int) *Int { return z.Sub(x, y) } for _, a := range sumZZ { arg := a testFunZZ(t, "AddZZ", AddZZ, arg) arg = argZZ{a.z, a.y, a.x} testFunZZ(t, "AddZZ symmetric", AddZZ, arg) arg = argZZ{a.x, a.z, a.y} testFunZZ(t, "SubZZ", SubZZ, arg) arg = argZZ{a.y, a.z, a.x} testFunZZ(t, "SubZZ symmetric", SubZZ, arg) } } func TestProdZZ(t *testing.T) { MulZZ := func(z, x, y *Int) *Int { return z.Mul(x, y) } for _, a := range prodZZ { arg := a testFunZZ(t, "MulZZ", MulZZ, arg) arg = argZZ{a.z, a.y, a.x} testFunZZ(t, "MulZZ symmetric", MulZZ, arg) } } // mulBytes returns x*y via grade school multiplication. Both inputs // and the result are assumed to be in big-endian representation (to // match the semantics of Int.Bytes and Int.SetBytes). func mulBytes(x, y []byte) []byte { z := make([]byte, len(x)+len(y)) // multiply k0 := len(z) - 1 for j := len(y) - 1; j >= 0; j-- { d := int(y[j]) if d != 0 { k := k0 carry := 0 for i := len(x) - 1; i >= 0; i-- { t := int(z[k]) + int(x[i])*d + carry z[k], carry = byte(t), t>>8 k-- } z[k] = byte(carry) } k0-- } // normalize (remove leading 0's) i := 0 for i < len(z) && z[i] == 0 { i++ } return z[i:] } func checkMul(a, b []byte) bool { var x, y, z1 Int x.SetBytes(a) y.SetBytes(b) z1.Mul(&x, &y) var z2 Int z2.SetBytes(mulBytes(a, b)) return z1.Cmp(&z2) == 0 } func TestMul(t *testing.T) { if err := quick.Check(checkMul, nil); err != nil { t.Error(err) } } var mulRangesZ = []struct { a, b int64 prod string }{ // entirely positive ranges are covered by mulRangesN {-1, 1, "0"}, {-2, -1, "2"}, {-3, -2, "6"}, {-3, -1, "-6"}, {1, 3, "6"}, {-10, -10, "-10"}, {0, -1, "1"}, // empty range {-1, -100, "1"}, // empty range {-1, 1, "0"}, // range includes 0 {-1e9, 0, "0"}, // range includes 0 {-1e9, 1e9, "0"}, // range includes 0 {-10, -1, "3628800"}, // 10! {-20, -2, "-2432902008176640000"}, // -20! {-99, -1, "-933262154439441526816992388562667004907159682643816214685929" + "638952175999932299156089414639761565182862536979208272237582" + "511852109168640000000000000000000000", // -99! }, } func TestMulRangeZ(t *testing.T) { var tmp Int // test entirely positive ranges for i, r := range mulRangesN { prod := tmp.MulRange(int64(r.a), int64(r.b)).String() if prod != r.prod { t.Errorf("#%da: got %s; want %s", i, prod, r.prod) } } // test other ranges for i, r := range mulRangesZ { prod := tmp.MulRange(r.a, r.b).String() if prod != r.prod { t.Errorf("#%db: got %s; want %s", i, prod, r.prod) } } } func TestBinomial(t *testing.T) { var z Int for _, test := range []struct { n, k int64 want string }{ {0, 0, "1"}, {0, 1, "0"}, {1, 0, "1"}, {1, 1, "1"}, {1, 10, "0"}, {4, 0, "1"}, {4, 1, "4"}, {4, 2, "6"}, {4, 3, "4"}, {4, 4, "1"}, {10, 1, "10"}, {10, 9, "10"}, {10, 5, "252"}, {11, 5, "462"}, {11, 6, "462"}, {100, 10, "17310309456440"}, {100, 90, "17310309456440"}, {1000, 10, "263409560461970212832400"}, {1000, 990, "263409560461970212832400"}, } { if got := z.Binomial(test.n, test.k).String(); got != test.want { t.Errorf("Binomial(%d, %d) = %s; want %s", test.n, test.k, got, test.want) } } } func BenchmarkBinomial(b *testing.B) { var z Int for i := b.N - 1; i >= 0; i-- { z.Binomial(1000, 990) } } // Examples from the Go Language Spec, section "Arithmetic operators" var divisionSignsTests = []struct { x, y int64 q, r int64 // T-division d, m int64 // Euclidian division }{ {5, 3, 1, 2, 1, 2}, {-5, 3, -1, -2, -2, 1}, {5, -3, -1, 2, -1, 2}, {-5, -3, 1, -2, 2, 1}, {1, 2, 0, 1, 0, 1}, {8, 4, 2, 0, 2, 0}, } func TestDivisionSigns(t *testing.T) { for i, test := range divisionSignsTests { x := NewInt(test.x) y := NewInt(test.y) q := NewInt(test.q) r := NewInt(test.r) d := NewInt(test.d) m := NewInt(test.m) q1 := new(Int).Quo(x, y) r1 := new(Int).Rem(x, y) if !isNormalized(q1) { t.Errorf("#%d Quo: %v is not normalized", i, *q1) } if !isNormalized(r1) { t.Errorf("#%d Rem: %v is not normalized", i, *r1) } if q1.Cmp(q) != 0 || r1.Cmp(r) != 0 { t.Errorf("#%d QuoRem: got (%s, %s), want (%s, %s)", i, q1, r1, q, r) } q2, r2 := new(Int).QuoRem(x, y, new(Int)) if !isNormalized(q2) { t.Errorf("#%d Quo: %v is not normalized", i, *q2) } if !isNormalized(r2) { t.Errorf("#%d Rem: %v is not normalized", i, *r2) } if q2.Cmp(q) != 0 || r2.Cmp(r) != 0 { t.Errorf("#%d QuoRem: got (%s, %s), want (%s, %s)", i, q2, r2, q, r) } d1 := new(Int).Div(x, y) m1 := new(Int).Mod(x, y) if !isNormalized(d1) { t.Errorf("#%d Div: %v is not normalized", i, *d1) } if !isNormalized(m1) { t.Errorf("#%d Mod: %v is not normalized", i, *m1) } if d1.Cmp(d) != 0 || m1.Cmp(m) != 0 { t.Errorf("#%d DivMod: got (%s, %s), want (%s, %s)", i, d1, m1, d, m) } d2, m2 := new(Int).DivMod(x, y, new(Int)) if !isNormalized(d2) { t.Errorf("#%d Div: %v is not normalized", i, *d2) } if !isNormalized(m2) { t.Errorf("#%d Mod: %v is not normalized", i, *m2) } if d2.Cmp(d) != 0 || m2.Cmp(m) != 0 { t.Errorf("#%d DivMod: got (%s, %s), want (%s, %s)", i, d2, m2, d, m) } } } func norm(x nat) nat { i := len(x) for i > 0 && x[i-1] == 0 { i-- } return x[:i] } func TestBits(t *testing.T) { for _, test := range []nat{ nil, {0}, {1}, {0, 1, 2, 3, 4}, {4, 3, 2, 1, 0}, {4, 3, 2, 1, 0, 0, 0, 0}, } { var z Int z.neg = true got := z.SetBits(test) want := norm(test) if got.abs.cmp(want) != 0 { t.Errorf("SetBits(%v) = %v; want %v", test, got.abs, want) } if got.neg { t.Errorf("SetBits(%v): got negative result", test) } bits := nat(z.Bits()) if bits.cmp(want) != 0 { t.Errorf("%v.Bits() = %v; want %v", z.abs, bits, want) } } } func checkSetBytes(b []byte) bool { hex1 := hex.EncodeToString(new(Int).SetBytes(b).Bytes()) hex2 := hex.EncodeToString(b) for len(hex1) < len(hex2) { hex1 = "0" + hex1 } for len(hex1) > len(hex2) { hex2 = "0" + hex2 } return hex1 == hex2 } func TestSetBytes(t *testing.T) { if err := quick.Check(checkSetBytes, nil); err != nil { t.Error(err) } } func checkBytes(b []byte) bool { b2 := new(Int).SetBytes(b).Bytes() return bytes.Equal(b, b2) } func TestBytes(t *testing.T) { if err := quick.Check(checkBytes, nil); err != nil { t.Error(err) } } func checkQuo(x, y []byte) bool { u := new(Int).SetBytes(x) v := new(Int).SetBytes(y) if len(v.abs) == 0 { return true } r := new(Int) q, r := new(Int).QuoRem(u, v, r) if r.Cmp(v) >= 0 { return false } uprime := new(Int).Set(q) uprime.Mul(uprime, v) uprime.Add(uprime, r) return uprime.Cmp(u) == 0 } var quoTests = []struct { x, y string q, r string }{ { "476217953993950760840509444250624797097991362735329973741718102894495832294430498335824897858659711275234906400899559094370964723884706254265559534144986498357", "9353930466774385905609975137998169297361893554149986716853295022578535724979483772383667534691121982974895531435241089241440253066816724367338287092081996", "50911", "1", }, { "11510768301994997771168", "1328165573307167369775", "8", "885443715537658812968", }, } func TestQuo(t *testing.T) { if err := quick.Check(checkQuo, nil); err != nil { t.Error(err) } for i, test := range quoTests { x, _ := new(Int).SetString(test.x, 10) y, _ := new(Int).SetString(test.y, 10) expectedQ, _ := new(Int).SetString(test.q, 10) expectedR, _ := new(Int).SetString(test.r, 10) r := new(Int) q, r := new(Int).QuoRem(x, y, r) if q.Cmp(expectedQ) != 0 || r.Cmp(expectedR) != 0 { t.Errorf("#%d got (%s, %s) want (%s, %s)", i, q, r, expectedQ, expectedR) } } } func TestQuoStepD6(t *testing.T) { // See Knuth, Volume 2, section 4.3.1, exercise 21. This code exercises // a code path which only triggers 1 in 10^{-19} cases. u := &Int{false, nat{0, 0, 1 + 1<<(_W-1), _M ^ (1 << (_W - 1))}} v := &Int{false, nat{5, 2 + 1<<(_W-1), 1 << (_W - 1)}} r := new(Int) q, r := new(Int).QuoRem(u, v, r) const expectedQ64 = "18446744073709551613" const expectedR64 = "3138550867693340382088035895064302439801311770021610913807" const expectedQ32 = "4294967293" const expectedR32 = "39614081266355540837921718287" if q.String() != expectedQ64 && q.String() != expectedQ32 || r.String() != expectedR64 && r.String() != expectedR32 { t.Errorf("got (%s, %s) want (%s, %s) or (%s, %s)", q, r, expectedQ64, expectedR64, expectedQ32, expectedR32) } } var bitLenTests = []struct { in string out int }{ {"-1", 1}, {"0", 0}, {"1", 1}, {"2", 2}, {"4", 3}, {"0xabc", 12}, {"0x8000", 16}, {"0x80000000", 32}, {"0x800000000000", 48}, {"0x8000000000000000", 64}, {"0x80000000000000000000", 80}, {"-0x4000000000000000000000", 87}, } func TestBitLen(t *testing.T) { for i, test := range bitLenTests { x, ok := new(Int).SetString(test.in, 0) if !ok { t.Errorf("#%d test input invalid: %s", i, test.in) continue } if n := x.BitLen(); n != test.out { t.Errorf("#%d got %d want %d", i, n, test.out) } } } var expTests = []struct { x, y, m string out string }{ // y <= 0 {"0", "0", "", "1"}, {"1", "0", "", "1"}, {"-10", "0", "", "1"}, {"1234", "-1", "", "1"}, // m == 1 {"0", "0", "1", "0"}, {"1", "0", "1", "0"}, {"-10", "0", "1", "0"}, {"1234", "-1", "1", "0"}, // misc {"5", "1", "3", "2"}, {"5", "-7", "", "1"}, {"-5", "-7", "", "1"}, {"5", "0", "", "1"}, {"-5", "0", "", "1"}, {"5", "1", "", "5"}, {"-5", "1", "", "-5"}, {"-5", "1", "7", "2"}, {"-2", "3", "2", "0"}, {"5", "2", "", "25"}, {"1", "65537", "2", "1"}, {"0x8000000000000000", "2", "", "0x40000000000000000000000000000000"}, {"0x8000000000000000", "2", "6719", "4944"}, {"0x8000000000000000", "3", "6719", "5447"}, {"0x8000000000000000", "1000", "6719", "1603"}, {"0x8000000000000000", "1000000", "6719", "3199"}, {"0x8000000000000000", "-1000000", "6719", "1"}, { "2938462938472983472983659726349017249287491026512746239764525612965293865296239471239874193284792387498274256129746192347", "298472983472983471903246121093472394872319615612417471234712061", "29834729834729834729347290846729561262544958723956495615629569234729836259263598127342374289365912465901365498236492183464", "23537740700184054162508175125554701713153216681790245129157191391322321508055833908509185839069455749219131480588829346291", }, // test case for issue 8822 { "-0x1BCE04427D8032319A89E5C4136456671AC620883F2C4139E57F91307C485AD2D6204F4F87A58262652DB5DBBAC72B0613E51B835E7153BEC6068F5C8D696B74DBD18FEC316AEF73985CF0475663208EB46B4F17DD9DA55367B03323E5491A70997B90C059FB34809E6EE55BCFBD5F2F52233BFE62E6AA9E4E26A1D4C2439883D14F2633D55D8AA66A1ACD5595E778AC3A280517F1157989E70C1A437B849F1877B779CC3CDDEDE2DAA6594A6C66D181A00A5F777EE60596D8773998F6E988DEAE4CCA60E4DDCF9590543C89F74F603259FCAD71660D30294FBBE6490300F78A9D63FA660DC9417B8B9DDA28BEB3977B621B988E23D4D954F322C3540541BC649ABD504C50FADFD9F0987D58A2BF689313A285E773FF02899A6EF887D1D4A0D2", "0xB08FFB20760FFED58FADA86DFEF71AD72AA0FA763219618FE022C197E54708BB1191C66470250FCE8879487507CEE41381CA4D932F81C2B3F1AB20B539D50DCD", "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}, } func TestExp(t *testing.T) { for i, test := range expTests { x, ok1 := new(Int).SetString(test.x, 0) y, ok2 := new(Int).SetString(test.y, 0) out, ok3 := new(Int).SetString(test.out, 0) var ok4 bool var m *Int if len(test.m) == 0 { m, ok4 = nil, true } else { m, ok4 = new(Int).SetString(test.m, 0) } if !ok1 || !ok2 || !ok3 || !ok4 { t.Errorf("#%d: error in input", i) continue } z1 := new(Int).Exp(x, y, m) if !isNormalized(z1) { t.Errorf("#%d: %v is not normalized", i, *z1) } if z1.Cmp(out) != 0 { t.Errorf("#%d: got %s want %s", i, z1, out) } if m == nil { // The result should be the same as for m == 0; // specifically, there should be no div-zero panic. m = &Int{abs: nat{}} // m != nil && len(m.abs) == 0 z2 := new(Int).Exp(x, y, m) if z2.Cmp(z1) != 0 { t.Errorf("#%d: got %s want %s", i, z2, z1) } } } } func checkGcd(aBytes, bBytes []byte) bool { x := new(Int) y := new(Int) a := new(Int).SetBytes(aBytes) b := new(Int).SetBytes(bBytes) d := new(Int).GCD(x, y, a, b) x.Mul(x, a) y.Mul(y, b) x.Add(x, y) return x.Cmp(d) == 0 } var gcdTests = []struct { d, x, y, a, b string }{ // a <= 0 || b <= 0 {"0", "0", "0", "0", "0"}, {"0", "0", "0", "0", "7"}, {"0", "0", "0", "11", "0"}, {"0", "0", "0", "-77", "35"}, {"0", "0", "0", "64515", "-24310"}, {"0", "0", "0", "-64515", "-24310"}, {"1", "-9", "47", "120", "23"}, {"7", "1", "-2", "77", "35"}, {"935", "-3", "8", "64515", "24310"}, {"935000000000000000", "-3", "8", "64515000000000000000", "24310000000000000000"}, {"1", "-221", "22059940471369027483332068679400581064239780177629666810348940098015901108344", "98920366548084643601728869055592650835572950932266967461790948584315647051443", "991"}, // test early exit (after one Euclidean iteration) in binaryGCD {"1", "", "", "1", "98920366548084643601728869055592650835572950932266967461790948584315647051443"}, } func testGcd(t *testing.T, d, x, y, a, b *Int) { var X *Int if x != nil { X = new(Int) } var Y *Int if y != nil { Y = new(Int) } D := new(Int).GCD(X, Y, a, b) if D.Cmp(d) != 0 { t.Errorf("GCD(%s, %s): got d = %s, want %s", a, b, D, d) } if x != nil && X.Cmp(x) != 0 { t.Errorf("GCD(%s, %s): got x = %s, want %s", a, b, X, x) } if y != nil && Y.Cmp(y) != 0 { t.Errorf("GCD(%s, %s): got y = %s, want %s", a, b, Y, y) } // binaryGCD requires a > 0 && b > 0 if a.Sign() <= 0 || b.Sign() <= 0 { return } D.binaryGCD(a, b) if D.Cmp(d) != 0 { t.Errorf("binaryGcd(%s, %s): got d = %s, want %s", a, b, D, d) } // check results in presence of aliasing (issue #11284) a2 := new(Int).Set(a) b2 := new(Int).Set(b) a2.binaryGCD(a2, b2) // result is same as 1st argument if a2.Cmp(d) != 0 { t.Errorf("binaryGcd(%s, %s): got d = %s, want %s", a, b, a2, d) } a2 = new(Int).Set(a) b2 = new(Int).Set(b) b2.binaryGCD(a2, b2) // result is same as 2nd argument if b2.Cmp(d) != 0 { t.Errorf("binaryGcd(%s, %s): got d = %s, want %s", a, b, b2, d) } } func TestGcd(t *testing.T) { for _, test := range gcdTests { d, _ := new(Int).SetString(test.d, 0) x, _ := new(Int).SetString(test.x, 0) y, _ := new(Int).SetString(test.y, 0) a, _ := new(Int).SetString(test.a, 0) b, _ := new(Int).SetString(test.b, 0) testGcd(t, d, nil, nil, a, b) testGcd(t, d, x, nil, a, b) testGcd(t, d, nil, y, a, b) testGcd(t, d, x, y, a, b) } quick.Check(checkGcd, nil) } var primes = []string{ "2", "3", "5", "7", "11", "13756265695458089029", "13496181268022124907", "10953742525620032441", "17908251027575790097", // https://golang.org/issue/638 "18699199384836356663", "98920366548084643601728869055592650835572950932266967461790948584315647051443", "94560208308847015747498523884063394671606671904944666360068158221458669711639", // http://primes.utm.edu/lists/small/small3.html "449417999055441493994709297093108513015373787049558499205492347871729927573118262811508386655998299074566974373711472560655026288668094291699357843464363003144674940345912431129144354948751003607115263071543163", "230975859993204150666423538988557839555560243929065415434980904258310530753006723857139742334640122533598517597674807096648905501653461687601339782814316124971547968912893214002992086353183070342498989426570593", "5521712099665906221540423207019333379125265462121169655563495403888449493493629943498064604536961775110765377745550377067893607246020694972959780839151452457728855382113555867743022746090187341871655890805971735385789993", "203956878356401977405765866929034577280193993314348263094772646453283062722701277632936616063144088173312372882677123879538709400158306567338328279154499698366071906766440037074217117805690872792848149112022286332144876183376326512083574821647933992961249917319836219304274280243803104015000563790123", // ECC primes: http://tools.ietf.org/html/draft-ladd-safecurves-02 "3618502788666131106986593281521497120414687020801267626233049500247285301239", // Curve1174: 2^251-9 "57896044618658097711785492504343953926634992332820282019728792003956564819949", // Curve25519: 2^255-19 "9850501549098619803069760025035903451269934817616361666987073351061430442874302652853566563721228910201656997576599", // E-382: 2^382-105 "42307582002575910332922579714097346549017899709713998034217522897561970639123926132812109468141778230245837569601494931472367", // Curve41417: 2^414-17 "6864797660130609714981900799081393217269435300143305409394463459185543183397656052122559640661454554977296311391480858037121987999716643812574028291115057151", // E-521: 2^521-1 } var composites = []string{ "0", "1", "21284175091214687912771199898307297748211672914763848041968395774954376176754", "6084766654921918907427900243509372380954290099172559290432744450051395395951", "84594350493221918389213352992032324280367711247940675652888030554255915464401", "82793403787388584738507275144194252681", } func TestProbablyPrime(t *testing.T) { nreps := 20 if testing.Short() { nreps = 1 } for i, s := range primes { p, _ := new(Int).SetString(s, 10) if !p.ProbablyPrime(nreps) { t.Errorf("#%d prime found to be non-prime (%s)", i, s) } } for i, s := range composites { c, _ := new(Int).SetString(s, 10) if c.ProbablyPrime(nreps) { t.Errorf("#%d composite found to be prime (%s)", i, s) } if testing.Short() { break } } // check that ProbablyPrime panics if n <= 0 c := NewInt(11) // a prime for _, n := range []int{-1, 0, 1} { func() { defer func() { if n <= 0 && recover() == nil { t.Fatalf("expected panic from ProbablyPrime(%d)", n) } }() if !c.ProbablyPrime(n) { t.Fatalf("%v should be a prime", c) } }() } } type intShiftTest struct { in string shift uint out string } var rshTests = []intShiftTest{ {"0", 0, "0"}, {"-0", 0, "0"}, {"0", 1, "0"}, {"0", 2, "0"}, {"1", 0, "1"}, {"1", 1, "0"}, {"1", 2, "0"}, {"2", 0, "2"}, {"2", 1, "1"}, {"-1", 0, "-1"}, {"-1", 1, "-1"}, {"-1", 10, "-1"}, {"-100", 2, "-25"}, {"-100", 3, "-13"}, {"-100", 100, "-1"}, {"4294967296", 0, "4294967296"}, {"4294967296", 1, "2147483648"}, {"4294967296", 2, "1073741824"}, {"18446744073709551616", 0, "18446744073709551616"}, {"18446744073709551616", 1, "9223372036854775808"}, {"18446744073709551616", 2, "4611686018427387904"}, {"18446744073709551616", 64, "1"}, {"340282366920938463463374607431768211456", 64, "18446744073709551616"}, {"340282366920938463463374607431768211456", 128, "1"}, } func TestRsh(t *testing.T) { for i, test := range rshTests { in, _ := new(Int).SetString(test.in, 10) expected, _ := new(Int).SetString(test.out, 10) out := new(Int).Rsh(in, test.shift) if !isNormalized(out) { t.Errorf("#%d: %v is not normalized", i, *out) } if out.Cmp(expected) != 0 { t.Errorf("#%d: got %s want %s", i, out, expected) } } } func TestRshSelf(t *testing.T) { for i, test := range rshTests { z, _ := new(Int).SetString(test.in, 10) expected, _ := new(Int).SetString(test.out, 10) z.Rsh(z, test.shift) if !isNormalized(z) { t.Errorf("#%d: %v is not normalized", i, *z) } if z.Cmp(expected) != 0 { t.Errorf("#%d: got %s want %s", i, z, expected) } } } var lshTests = []intShiftTest{ {"0", 0, "0"}, {"0", 1, "0"}, {"0", 2, "0"}, {"1", 0, "1"}, {"1", 1, "2"}, {"1", 2, "4"}, {"2", 0, "2"}, {"2", 1, "4"}, {"2", 2, "8"}, {"-87", 1, "-174"}, {"4294967296", 0, "4294967296"}, {"4294967296", 1, "8589934592"}, {"4294967296", 2, "17179869184"}, {"18446744073709551616", 0, "18446744073709551616"}, {"9223372036854775808", 1, "18446744073709551616"}, {"4611686018427387904", 2, "18446744073709551616"}, {"1", 64, "18446744073709551616"}, {"18446744073709551616", 64, "340282366920938463463374607431768211456"}, {"1", 128, "340282366920938463463374607431768211456"}, } func TestLsh(t *testing.T) { for i, test := range lshTests { in, _ := new(Int).SetString(test.in, 10) expected, _ := new(Int).SetString(test.out, 10) out := new(Int).Lsh(in, test.shift) if !isNormalized(out) { t.Errorf("#%d: %v is not normalized", i, *out) } if out.Cmp(expected) != 0 { t.Errorf("#%d: got %s want %s", i, out, expected) } } } func TestLshSelf(t *testing.T) { for i, test := range lshTests { z, _ := new(Int).SetString(test.in, 10) expected, _ := new(Int).SetString(test.out, 10) z.Lsh(z, test.shift) if !isNormalized(z) { t.Errorf("#%d: %v is not normalized", i, *z) } if z.Cmp(expected) != 0 { t.Errorf("#%d: got %s want %s", i, z, expected) } } } func TestLshRsh(t *testing.T) { for i, test := range rshTests { in, _ := new(Int).SetString(test.in, 10) out := new(Int).Lsh(in, test.shift) out = out.Rsh(out, test.shift) if !isNormalized(out) { t.Errorf("#%d: %v is not normalized", i, *out) } if in.Cmp(out) != 0 { t.Errorf("#%d: got %s want %s", i, out, in) } } for i, test := range lshTests { in, _ := new(Int).SetString(test.in, 10) out := new(Int).Lsh(in, test.shift) out.Rsh(out, test.shift) if !isNormalized(out) { t.Errorf("#%d: %v is not normalized", i, *out) } if in.Cmp(out) != 0 { t.Errorf("#%d: got %s want %s", i, out, in) } } } var int64Tests = []int64{ 0, 1, -1, 4294967295, -4294967295, 4294967296, -4294967296, 9223372036854775807, -9223372036854775807, -9223372036854775808, } func TestInt64(t *testing.T) { for i, testVal := range int64Tests { in := NewInt(testVal) out := in.Int64() if out != testVal { t.Errorf("#%d got %d want %d", i, out, testVal) } } } var uint64Tests = []uint64{ 0, 1, 4294967295, 4294967296, 8589934591, 8589934592, 9223372036854775807, 9223372036854775808, 18446744073709551615, // 1<<64 - 1 } func TestUint64(t *testing.T) { in := new(Int) for i, testVal := range uint64Tests { in.SetUint64(testVal) out := in.Uint64() if out != testVal { t.Errorf("#%d got %d want %d", i, out, testVal) } str := fmt.Sprint(testVal) strOut := in.String() if strOut != str { t.Errorf("#%d.String got %s want %s", i, strOut, str) } } } var bitwiseTests = []struct { x, y string and, or, xor, andNot string }{ {"0x00", "0x00", "0x00", "0x00", "0x00", "0x00"}, {"0x00", "0x01", "0x00", "0x01", "0x01", "0x00"}, {"0x01", "0x00", "0x00", "0x01", "0x01", "0x01"}, {"-0x01", "0x00", "0x00", "-0x01", "-0x01", "-0x01"}, {"-0xaf", "-0x50", "-0xf0", "-0x0f", "0xe1", "0x41"}, {"0x00", "-0x01", "0x00", "-0x01", "-0x01", "0x00"}, {"0x01", "0x01", "0x01", "0x01", "0x00", "0x00"}, {"-0x01", "-0x01", "-0x01", "-0x01", "0x00", "0x00"}, {"0x07", "0x08", "0x00", "0x0f", "0x0f", "0x07"}, {"0x05", "0x0f", "0x05", "0x0f", "0x0a", "0x00"}, {"0xff", "-0x0a", "0xf6", "-0x01", "-0xf7", "0x09"}, {"0x013ff6", "0x9a4e", "0x1a46", "0x01bffe", "0x01a5b8", "0x0125b0"}, {"-0x013ff6", "0x9a4e", "0x800a", "-0x0125b2", "-0x01a5bc", "-0x01c000"}, {"-0x013ff6", "-0x9a4e", "-0x01bffe", "-0x1a46", "0x01a5b8", "0x8008"}, { "0x1000009dc6e3d9822cba04129bcbe3401", "0xb9bd7d543685789d57cb918e833af352559021483cdb05cc21fd", "0x1000001186210100001000009048c2001", "0xb9bd7d543685789d57cb918e8bfeff7fddb2ebe87dfbbdfe35fd", "0xb9bd7d543685789d57ca918e8ae69d6fcdb2eae87df2b97215fc", "0x8c40c2d8822caa04120b8321400", }, { "0x1000009dc6e3d9822cba04129bcbe3401", "-0xb9bd7d543685789d57cb918e833af352559021483cdb05cc21fd", "0x8c40c2d8822caa04120b8321401", "-0xb9bd7d543685789d57ca918e82229142459020483cd2014001fd", "-0xb9bd7d543685789d57ca918e8ae69d6fcdb2eae87df2b97215fe", "0x1000001186210100001000009048c2000", }, { "-0x1000009dc6e3d9822cba04129bcbe3401", "-0xb9bd7d543685789d57cb918e833af352559021483cdb05cc21fd", "-0xb9bd7d543685789d57cb918e8bfeff7fddb2ebe87dfbbdfe35fd", "-0x1000001186210100001000009048c2001", "0xb9bd7d543685789d57ca918e8ae69d6fcdb2eae87df2b97215fc", "0xb9bd7d543685789d57ca918e82229142459020483cd2014001fc", }, } type bitFun func(z, x, y *Int) *Int func testBitFun(t *testing.T, msg string, f bitFun, x, y *Int, exp string) { expected := new(Int) expected.SetString(exp, 0) out := f(new(Int), x, y) if out.Cmp(expected) != 0 { t.Errorf("%s: got %s want %s", msg, out, expected) } } func testBitFunSelf(t *testing.T, msg string, f bitFun, x, y *Int, exp string) { self := new(Int) self.Set(x) expected := new(Int) expected.SetString(exp, 0) self = f(self, self, y) if self.Cmp(expected) != 0 { t.Errorf("%s: got %s want %s", msg, self, expected) } } func altBit(x *Int, i int) uint { z := new(Int).Rsh(x, uint(i)) z = z.And(z, NewInt(1)) if z.Cmp(new(Int)) != 0 { return 1 } return 0 } func altSetBit(z *Int, x *Int, i int, b uint) *Int { one := NewInt(1) m := one.Lsh(one, uint(i)) switch b { case 1: return z.Or(x, m) case 0: return z.AndNot(x, m) } panic("set bit is not 0 or 1") } func testBitset(t *testing.T, x *Int) { n := x.BitLen() z := new(Int).Set(x) z1 := new(Int).Set(x) for i := 0; i < n+10; i++ { old := z.Bit(i) old1 := altBit(z1, i) if old != old1 { t.Errorf("bitset: inconsistent value for Bit(%s, %d), got %v want %v", z1, i, old, old1) } z := new(Int).SetBit(z, i, 1) z1 := altSetBit(new(Int), z1, i, 1) if z.Bit(i) == 0 { t.Errorf("bitset: bit %d of %s got 0 want 1", i, x) } if z.Cmp(z1) != 0 { t.Errorf("bitset: inconsistent value after SetBit 1, got %s want %s", z, z1) } z.SetBit(z, i, 0) altSetBit(z1, z1, i, 0) if z.Bit(i) != 0 { t.Errorf("bitset: bit %d of %s got 1 want 0", i, x) } if z.Cmp(z1) != 0 { t.Errorf("bitset: inconsistent value after SetBit 0, got %s want %s", z, z1) } altSetBit(z1, z1, i, old) z.SetBit(z, i, old) if z.Cmp(z1) != 0 { t.Errorf("bitset: inconsistent value after SetBit old, got %s want %s", z, z1) } } if z.Cmp(x) != 0 { t.Errorf("bitset: got %s want %s", z, x) } } var bitsetTests = []struct { x string i int b uint }{ {"0", 0, 0}, {"0", 200, 0}, {"1", 0, 1}, {"1", 1, 0}, {"-1", 0, 1}, {"-1", 200, 1}, {"0x2000000000000000000000000000", 108, 0}, {"0x2000000000000000000000000000", 109, 1}, {"0x2000000000000000000000000000", 110, 0}, {"-0x2000000000000000000000000001", 108, 1}, {"-0x2000000000000000000000000001", 109, 0}, {"-0x2000000000000000000000000001", 110, 1}, } func TestBitSet(t *testing.T) { for _, test := range bitwiseTests { x := new(Int) x.SetString(test.x, 0) testBitset(t, x) x = new(Int) x.SetString(test.y, 0) testBitset(t, x) } for i, test := range bitsetTests { x := new(Int) x.SetString(test.x, 0) b := x.Bit(test.i) if b != test.b { t.Errorf("#%d got %v want %v", i, b, test.b) } } z := NewInt(1) z.SetBit(NewInt(0), 2, 1) if z.Cmp(NewInt(4)) != 0 { t.Errorf("destination leaked into result; got %s want 4", z) } } func BenchmarkBitset(b *testing.B) { z := new(Int) z.SetBit(z, 512, 1) b.ResetTimer() b.StartTimer() for i := b.N - 1; i >= 0; i-- { z.SetBit(z, i&512, 1) } } func BenchmarkBitsetNeg(b *testing.B) { z := NewInt(-1) z.SetBit(z, 512, 0) b.ResetTimer() b.StartTimer() for i := b.N - 1; i >= 0; i-- { z.SetBit(z, i&512, 0) } } func BenchmarkBitsetOrig(b *testing.B) { z := new(Int) altSetBit(z, z, 512, 1) b.ResetTimer() b.StartTimer() for i := b.N - 1; i >= 0; i-- { altSetBit(z, z, i&512, 1) } } func BenchmarkBitsetNegOrig(b *testing.B) { z := NewInt(-1) altSetBit(z, z, 512, 0) b.ResetTimer() b.StartTimer() for i := b.N - 1; i >= 0; i-- { altSetBit(z, z, i&512, 0) } } func TestBitwise(t *testing.T) { x := new(Int) y := new(Int) for _, test := range bitwiseTests { x.SetString(test.x, 0) y.SetString(test.y, 0) testBitFun(t, "and", (*Int).And, x, y, test.and) testBitFunSelf(t, "and", (*Int).And, x, y, test.and) testBitFun(t, "andNot", (*Int).AndNot, x, y, test.andNot) testBitFunSelf(t, "andNot", (*Int).AndNot, x, y, test.andNot) testBitFun(t, "or", (*Int).Or, x, y, test.or) testBitFunSelf(t, "or", (*Int).Or, x, y, test.or) testBitFun(t, "xor", (*Int).Xor, x, y, test.xor) testBitFunSelf(t, "xor", (*Int).Xor, x, y, test.xor) } } var notTests = []struct { in string out string }{ {"0", "-1"}, {"1", "-2"}, {"7", "-8"}, {"0", "-1"}, {"-81910", "81909"}, { "298472983472983471903246121093472394872319615612417471234712061", "-298472983472983471903246121093472394872319615612417471234712062", }, } func TestNot(t *testing.T) { in := new(Int) out := new(Int) expected := new(Int) for i, test := range notTests { in.SetString(test.in, 10) expected.SetString(test.out, 10) out = out.Not(in) if out.Cmp(expected) != 0 { t.Errorf("#%d: got %s want %s", i, out, expected) } out = out.Not(out) if out.Cmp(in) != 0 { t.Errorf("#%d: got %s want %s", i, out, in) } } } var modInverseTests = []struct { element string modulus string }{ {"1234567", "458948883992"}, {"239487239847", "2410312426921032588552076022197566074856950548502459942654116941958108831682612228890093858261341614673227141477904012196503648957050582631942730706805009223062734745341073406696246014589361659774041027169249453200378729434170325843778659198143763193776859869524088940195577346119843545301547043747207749969763750084308926339295559968882457872412993810129130294592999947926365264059284647209730384947211681434464714438488520940127459844288859336526896320919633919"}, } func TestModInverse(t *testing.T) { var element, modulus, gcd, inverse Int one := NewInt(1) for i, test := range modInverseTests { (&element).SetString(test.element, 10) (&modulus).SetString(test.modulus, 10) (&inverse).ModInverse(&element, &modulus) (&inverse).Mul(&inverse, &element) (&inverse).Mod(&inverse, &modulus) if (&inverse).Cmp(one) != 0 { t.Errorf("#%d: failed (e·e^(-1)=%s)", i, &inverse) } } // exhaustive test for small values for n := 2; n < 100; n++ { (&modulus).SetInt64(int64(n)) for x := 1; x < n; x++ { (&element).SetInt64(int64(x)) (&gcd).GCD(nil, nil, &element, &modulus) if (&gcd).Cmp(one) != 0 { continue } (&inverse).ModInverse(&element, &modulus) (&inverse).Mul(&inverse, &element) (&inverse).Mod(&inverse, &modulus) if (&inverse).Cmp(one) != 0 { t.Errorf("ModInverse(%d,%d)*%d%%%d=%d, not 1", &element, &modulus, &element, &modulus, &inverse) } } } } // testModSqrt is a helper for TestModSqrt, // which checks that ModSqrt can compute a square-root of elt^2. func testModSqrt(t *testing.T, elt, mod, sq, sqrt *Int) bool { var sqChk, sqrtChk, sqrtsq Int sq.Mul(elt, elt) sq.Mod(sq, mod) z := sqrt.ModSqrt(sq, mod) if z != sqrt { t.Errorf("ModSqrt returned wrong value %s", z) } // test ModSqrt arguments outside the range [0,mod) sqChk.Add(sq, mod) z = sqrtChk.ModSqrt(&sqChk, mod) if z != &sqrtChk || z.Cmp(sqrt) != 0 { t.Errorf("ModSqrt returned inconsistent value %s", z) } sqChk.Sub(sq, mod) z = sqrtChk.ModSqrt(&sqChk, mod) if z != &sqrtChk || z.Cmp(sqrt) != 0 { t.Errorf("ModSqrt returned inconsistent value %s", z) } // make sure we actually got a square root if sqrt.Cmp(elt) == 0 { return true // we found the "desired" square root } sqrtsq.Mul(sqrt, sqrt) // make sure we found the "other" one sqrtsq.Mod(&sqrtsq, mod) return sq.Cmp(&sqrtsq) == 0 } func TestModSqrt(t *testing.T) { var elt, mod, modx4, sq, sqrt Int r := rand.New(rand.NewSource(9)) for i, s := range primes[1:] { // skip 2, use only odd primes mod.SetString(s, 10) modx4.Lsh(&mod, 2) // test a few random elements per prime for x := 1; x < 5; x++ { elt.Rand(r, &modx4) elt.Sub(&elt, &mod) // test range [-mod, 3*mod) if !testModSqrt(t, &elt, &mod, &sq, &sqrt) { t.Errorf("#%d: failed (sqrt(e) = %s)", i, &sqrt) } } } // exhaustive test for small values for n := 3; n < 100; n++ { mod.SetInt64(int64(n)) if !mod.ProbablyPrime(10) { continue } isSquare := make([]bool, n) // test all the squares for x := 1; x < n; x++ { elt.SetInt64(int64(x)) if !testModSqrt(t, &elt, &mod, &sq, &sqrt) { t.Errorf("#%d: failed (sqrt(%d,%d) = %s)", x, &elt, &mod, &sqrt) } isSquare[sq.Uint64()] = true } // test all non-squares for x := 1; x < n; x++ { sq.SetInt64(int64(x)) z := sqrt.ModSqrt(&sq, &mod) if !isSquare[x] && z != nil { t.Errorf("#%d: failed (sqrt(%d,%d) = nil)", x, &sqrt, &mod) } } } } func TestJacobi(t *testing.T) { testCases := []struct { x, y int64 result int }{ {0, 1, 1}, {0, -1, 1}, {1, 1, 1}, {1, -1, 1}, {0, 5, 0}, {1, 5, 1}, {2, 5, -1}, {-2, 5, -1}, {2, -5, -1}, {-2, -5, 1}, {3, 5, -1}, {5, 5, 0}, {-5, 5, 0}, {6, 5, 1}, {6, -5, 1}, {-6, 5, 1}, {-6, -5, -1}, } var x, y Int for i, test := range testCases { x.SetInt64(test.x) y.SetInt64(test.y) expected := test.result actual := Jacobi(&x, &y) if actual != expected { t.Errorf("#%d: Jacobi(%d, %d) = %d, but expected %d", i, test.x, test.y, actual, expected) } } } func TestJacobiPanic(t *testing.T) { const failureMsg = "test failure" defer func() { msg := recover() if msg == nil || msg == failureMsg { panic(msg) } t.Log(msg) }() x := NewInt(1) y := NewInt(2) // Jacobi should panic when the second argument is even. Jacobi(x, y) panic(failureMsg) } var encodingTests = []string{ "-539345864568634858364538753846587364875430589374589", "-678645873", "-100", "-2", "-1", "0", "1", "2", "10", "42", "1234567890", "298472983472983471903246121093472394872319615612417471234712061", } func TestIntGobEncoding(t *testing.T) { var medium bytes.Buffer enc := gob.NewEncoder(&medium) dec := gob.NewDecoder(&medium) for _, test := range encodingTests { medium.Reset() // empty buffer for each test case (in case of failures) var tx Int tx.SetString(test, 10) if err := enc.Encode(&tx); err != nil { t.Errorf("encoding of %s failed: %s", &tx, err) } var rx Int if err := dec.Decode(&rx); err != nil { t.Errorf("decoding of %s failed: %s", &tx, err) } if rx.Cmp(&tx) != 0 { t.Errorf("transmission of %s failed: got %s want %s", &tx, &rx, &tx) } } } // Sending a nil Int pointer (inside a slice) on a round trip through gob should yield a zero. // TODO: top-level nils. func TestGobEncodingNilIntInSlice(t *testing.T) { buf := new(bytes.Buffer) enc := gob.NewEncoder(buf) dec := gob.NewDecoder(buf) var in = make([]*Int, 1) err := enc.Encode(&in) if err != nil { t.Errorf("gob encode failed: %q", err) } var out []*Int err = dec.Decode(&out) if err != nil { t.Fatalf("gob decode failed: %q", err) } if len(out) != 1 { t.Fatalf("wrong len; want 1 got %d", len(out)) } var zero Int if out[0].Cmp(&zero) != 0 { t.Errorf("transmission of (*Int)(nill) failed: got %s want 0", out) } } func TestIntJSONEncoding(t *testing.T) { for _, test := range encodingTests { var tx Int tx.SetString(test, 10) b, err := json.Marshal(&tx) if err != nil { t.Errorf("marshaling of %s failed: %s", &tx, err) } var rx Int if err := json.Unmarshal(b, &rx); err != nil { t.Errorf("unmarshaling of %s failed: %s", &tx, err) } if rx.Cmp(&tx) != 0 { t.Errorf("JSON encoding of %s failed: got %s want %s", &tx, &rx, &tx) } } } var intVals = []string{ "-141592653589793238462643383279502884197169399375105820974944592307816406286", "-1415926535897932384626433832795028841971", "-141592653589793", "-1", "0", "1", "141592653589793", "1415926535897932384626433832795028841971", "141592653589793238462643383279502884197169399375105820974944592307816406286", } func TestIntJSONEncodingTextMarshaller(t *testing.T) { for _, num := range intVals { var tx Int tx.SetString(num, 0) b, err := json.Marshal(&tx) if err != nil { t.Errorf("marshaling of %s failed: %s", &tx, err) continue } var rx Int if err := json.Unmarshal(b, &rx); err != nil { t.Errorf("unmarshaling of %s failed: %s", &tx, err) continue } if rx.Cmp(&tx) != 0 { t.Errorf("JSON encoding of %s failed: got %s want %s", &tx, &rx, &tx) } } } func TestIntXMLEncodingTextMarshaller(t *testing.T) { for _, num := range intVals { var tx Int tx.SetString(num, 0) b, err := xml.Marshal(&tx) if err != nil { t.Errorf("marshaling of %s failed: %s", &tx, err) continue } var rx Int if err := xml.Unmarshal(b, &rx); err != nil { t.Errorf("unmarshaling of %s failed: %s", &tx, err) continue } if rx.Cmp(&tx) != 0 { t.Errorf("XML encoding of %s failed: got %s want %s", &tx, &rx, &tx) } } } func TestIssue2607(t *testing.T) { // This code sequence used to hang. n := NewInt(10) n.Rand(rand.New(rand.NewSource(9)), n) }