|  | // Copyright 2015 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" | 
|  | "fmt" | 
|  | "io" | 
|  | "math" | 
|  | "reflect" | 
|  | "strconv" | 
|  | "strings" | 
|  | "testing" | 
|  | ) | 
|  |  | 
|  | var exponentTests = []struct { | 
|  | s       string // string to be scanned | 
|  | base2ok bool   // true if 'p'/'P' exponents are accepted | 
|  | sepOk   bool   // true if '_' separators are accepted | 
|  | x       int64  // expected exponent | 
|  | b       int    // expected exponent base | 
|  | err     error  // expected error | 
|  | next    rune   // next character (or 0, if at EOF) | 
|  | }{ | 
|  | // valid, without separators | 
|  | {"", false, false, 0, 10, nil, 0}, | 
|  | {"1", false, false, 0, 10, nil, '1'}, | 
|  | {"e0", false, false, 0, 10, nil, 0}, | 
|  | {"E1", false, false, 1, 10, nil, 0}, | 
|  | {"e+10", false, false, 10, 10, nil, 0}, | 
|  | {"e-10", false, false, -10, 10, nil, 0}, | 
|  | {"e123456789a", false, false, 123456789, 10, nil, 'a'}, | 
|  | {"p", false, false, 0, 10, nil, 'p'}, | 
|  | {"P+100", false, false, 0, 10, nil, 'P'}, | 
|  | {"p0", true, false, 0, 2, nil, 0}, | 
|  | {"P-123", true, false, -123, 2, nil, 0}, | 
|  | {"p+0a", true, false, 0, 2, nil, 'a'}, | 
|  | {"p+123__", true, false, 123, 2, nil, '_'}, // '_' is not part of the number anymore | 
|  |  | 
|  | // valid, with separators | 
|  | {"e+1_0", false, true, 10, 10, nil, 0}, | 
|  | {"e-1_0", false, true, -10, 10, nil, 0}, | 
|  | {"e123_456_789a", false, true, 123456789, 10, nil, 'a'}, | 
|  | {"P+1_00", false, true, 0, 10, nil, 'P'}, | 
|  | {"p-1_2_3", true, true, -123, 2, nil, 0}, | 
|  |  | 
|  | // invalid: no digits | 
|  | {"e", false, false, 0, 10, errNoDigits, 0}, | 
|  | {"ef", false, false, 0, 10, errNoDigits, 'f'}, | 
|  | {"e+", false, false, 0, 10, errNoDigits, 0}, | 
|  | {"E-x", false, false, 0, 10, errNoDigits, 'x'}, | 
|  | {"p", true, false, 0, 2, errNoDigits, 0}, | 
|  | {"P-", true, false, 0, 2, errNoDigits, 0}, | 
|  | {"p+e", true, false, 0, 2, errNoDigits, 'e'}, | 
|  | {"e+_x", false, true, 0, 10, errNoDigits, 'x'}, | 
|  |  | 
|  | // invalid: incorrect use of separator | 
|  | {"e0_", false, true, 0, 10, errInvalSep, 0}, | 
|  | {"e_0", false, true, 0, 10, errInvalSep, 0}, | 
|  | {"e-1_2__3", false, true, -123, 10, errInvalSep, 0}, | 
|  | } | 
|  |  | 
|  | func TestScanExponent(t *testing.T) { | 
|  | for _, a := range exponentTests { | 
|  | r := strings.NewReader(a.s) | 
|  | x, b, err := scanExponent(r, a.base2ok, a.sepOk) | 
|  | if err != a.err { | 
|  | t.Errorf("scanExponent%+v\n\tgot error = %v; want %v", a, err, a.err) | 
|  | } | 
|  | if x != a.x { | 
|  | t.Errorf("scanExponent%+v\n\tgot z = %v; want %v", a, x, a.x) | 
|  | } | 
|  | if b != a.b { | 
|  | t.Errorf("scanExponent%+v\n\tgot b = %d; want %d", a, b, a.b) | 
|  | } | 
|  | next, _, err := r.ReadRune() | 
|  | if err == io.EOF { | 
|  | next = 0 | 
|  | err = nil | 
|  | } | 
|  | if err == nil && next != a.next { | 
|  | t.Errorf("scanExponent%+v\n\tgot next = %q; want %q", a, next, a.next) | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | type StringTest struct { | 
|  | in, out string | 
|  | ok      bool | 
|  | } | 
|  |  | 
|  | var setStringTests = []StringTest{ | 
|  | // invalid | 
|  | {in: "1e"}, | 
|  | {in: "1.e"}, | 
|  | {in: "1e+14e-5"}, | 
|  | {in: "1e4.5"}, | 
|  | {in: "r"}, | 
|  | {in: "a/b"}, | 
|  | {in: "a.b"}, | 
|  | {in: "1/0"}, | 
|  | {in: "4/3/2"}, // issue 17001 | 
|  | {in: "4/3/"}, | 
|  | {in: "4/3."}, | 
|  | {in: "4/"}, | 
|  | {in: "13e-9223372036854775808"}, // CVE-2022-23772 | 
|  |  | 
|  | // valid | 
|  | {"0", "0", true}, | 
|  | {"-0", "0", true}, | 
|  | {"1", "1", true}, | 
|  | {"-1", "-1", true}, | 
|  | {"1.", "1", true}, | 
|  | {"1e0", "1", true}, | 
|  | {"1.e1", "10", true}, | 
|  | {"-0.1", "-1/10", true}, | 
|  | {"-.1", "-1/10", true}, | 
|  | {"2/4", "1/2", true}, | 
|  | {".25", "1/4", true}, | 
|  | {"-1/5", "-1/5", true}, | 
|  | {"8129567.7690E14", "812956776900000000000", true}, | 
|  | {"78189e+4", "781890000", true}, | 
|  | {"553019.8935e+8", "55301989350000", true}, | 
|  | {"98765432109876543210987654321e-10", "98765432109876543210987654321/10000000000", true}, | 
|  | {"9877861857500000E-7", "3951144743/4", true}, | 
|  | {"2169378.417e-3", "2169378417/1000000", true}, | 
|  | {"884243222337379604041632732738665534", "884243222337379604041632732738665534", true}, | 
|  | {"53/70893980658822810696", "53/70893980658822810696", true}, | 
|  | {"106/141787961317645621392", "53/70893980658822810696", true}, | 
|  | {"204211327800791583.81095", "4084226556015831676219/20000", true}, | 
|  | {"0e9999999999", "0", true}, // issue #16176 | 
|  | } | 
|  |  | 
|  | // These are not supported by fmt.Fscanf. | 
|  | var setStringTests2 = []StringTest{ | 
|  | // invalid | 
|  | {in: "4/3x"}, | 
|  | {in: "0/-1"}, | 
|  | {in: "-1/-1"}, | 
|  |  | 
|  | // invalid with separators | 
|  | // (smoke tests only - a comprehensive set of tests is in natconv_test.go) | 
|  | {in: "10_/1"}, | 
|  | {in: "_10/1"}, | 
|  | {in: "1/1__0"}, | 
|  |  | 
|  | // valid | 
|  | {"0b1000/3", "8/3", true}, | 
|  | {"0B1000/0x8", "1", true}, | 
|  | {"-010/1", "-8", true}, // 0-prefix indicates octal in this case | 
|  | {"-010.0", "-10", true}, | 
|  | {"-0o10/1", "-8", true}, | 
|  | {"0x10/1", "16", true}, | 
|  | {"0x10/0x20", "1/2", true}, | 
|  |  | 
|  | {"0010", "10", true}, // 0-prefix is ignored in this case (not a fraction) | 
|  | {"0x10.0", "16", true}, | 
|  | {"0x1.8", "3/2", true}, | 
|  | {"0X1.8p4", "24", true}, | 
|  | {"0x1.1E2", "2289/2048", true}, // E is part of hex mantissa, not exponent | 
|  | {"0b1.1E2", "150", true}, | 
|  | {"0B1.1P3", "12", true}, | 
|  | {"0o10e-2", "2/25", true}, | 
|  | {"0O10p-3", "1", true}, | 
|  |  | 
|  | // valid with separators | 
|  | // (smoke tests only - a comprehensive set of tests is in natconv_test.go) | 
|  | {"0b_1000/3", "8/3", true}, | 
|  | {"0B_10_00/0x8", "1", true}, | 
|  | {"0xdead/0B1101_1110_1010_1101", "1", true}, | 
|  | {"0B1101_1110_1010_1101/0XD_E_A_D", "1", true}, | 
|  | {"1_000.0", "1000", true}, | 
|  |  | 
|  | {"0x_10.0", "16", true}, | 
|  | {"0x1_0.0", "16", true}, | 
|  | {"0x1.8_0", "3/2", true}, | 
|  | {"0X1.8p0_4", "24", true}, | 
|  | {"0b1.1_0E2", "150", true}, | 
|  | {"0o1_0e-2", "2/25", true}, | 
|  | {"0O_10p-3", "1", true}, | 
|  | } | 
|  |  | 
|  | func TestRatSetString(t *testing.T) { | 
|  | var tests []StringTest | 
|  | tests = append(tests, setStringTests...) | 
|  | tests = append(tests, setStringTests2...) | 
|  |  | 
|  | for i, test := range tests { | 
|  | x, ok := new(Rat).SetString(test.in) | 
|  |  | 
|  | if ok { | 
|  | if !test.ok { | 
|  | t.Errorf("#%d SetString(%q) expected failure", i, test.in) | 
|  | } else if x.RatString() != test.out { | 
|  | t.Errorf("#%d SetString(%q) got %s want %s", i, test.in, x.RatString(), test.out) | 
|  | } | 
|  | } else { | 
|  | if test.ok { | 
|  | t.Errorf("#%d SetString(%q) expected success", i, test.in) | 
|  | } else if x != nil { | 
|  | t.Errorf("#%d SetString(%q) got %p want nil", i, test.in, x) | 
|  | } | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | func TestRatSetStringZero(t *testing.T) { | 
|  | got, _ := new(Rat).SetString("0") | 
|  | want := new(Rat).SetInt64(0) | 
|  | if !reflect.DeepEqual(got, want) { | 
|  | t.Errorf("got %#+v, want %#+v", got, want) | 
|  | } | 
|  | } | 
|  |  | 
|  | func TestRatScan(t *testing.T) { | 
|  | var buf bytes.Buffer | 
|  | for i, test := range setStringTests { | 
|  | x := new(Rat) | 
|  | buf.Reset() | 
|  | buf.WriteString(test.in) | 
|  |  | 
|  | _, err := fmt.Fscanf(&buf, "%v", x) | 
|  | if err == nil != test.ok { | 
|  | if test.ok { | 
|  | t.Errorf("#%d (%s) error: %s", i, test.in, err) | 
|  | } else { | 
|  | t.Errorf("#%d (%s) expected error", i, test.in) | 
|  | } | 
|  | continue | 
|  | } | 
|  | if err == nil && x.RatString() != test.out { | 
|  | t.Errorf("#%d got %s want %s", i, x.RatString(), test.out) | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | var floatStringTests = []struct { | 
|  | in   string | 
|  | prec int | 
|  | out  string | 
|  | }{ | 
|  | {"0", 0, "0"}, | 
|  | {"0", 4, "0.0000"}, | 
|  | {"1", 0, "1"}, | 
|  | {"1", 2, "1.00"}, | 
|  | {"-1", 0, "-1"}, | 
|  | {"0.05", 1, "0.1"}, | 
|  | {"-0.05", 1, "-0.1"}, | 
|  | {".25", 2, "0.25"}, | 
|  | {".25", 1, "0.3"}, | 
|  | {".25", 3, "0.250"}, | 
|  | {"-1/3", 3, "-0.333"}, | 
|  | {"-2/3", 4, "-0.6667"}, | 
|  | {"0.96", 1, "1.0"}, | 
|  | {"0.999", 2, "1.00"}, | 
|  | {"0.9", 0, "1"}, | 
|  | {".25", -1, "0"}, | 
|  | {".55", -1, "1"}, | 
|  | } | 
|  |  | 
|  | func TestFloatString(t *testing.T) { | 
|  | for i, test := range floatStringTests { | 
|  | x, _ := new(Rat).SetString(test.in) | 
|  |  | 
|  | if x.FloatString(test.prec) != test.out { | 
|  | t.Errorf("#%d got %s want %s", i, x.FloatString(test.prec), test.out) | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | // Test inputs to Rat.SetString. The prefix "long:" causes the test | 
|  | // to be skipped except in -long mode.  (The threshold is about 500us.) | 
|  | var float64inputs = []string{ | 
|  | // Constants plundered from strconv/testfp.txt. | 
|  |  | 
|  | // Table 1: Stress Inputs for Conversion to 53-bit Binary, < 1/2 ULP | 
|  | "5e+125", | 
|  | "69e+267", | 
|  | "999e-026", | 
|  | "7861e-034", | 
|  | "75569e-254", | 
|  | "928609e-261", | 
|  | "9210917e+080", | 
|  | "84863171e+114", | 
|  | "653777767e+273", | 
|  | "5232604057e-298", | 
|  | "27235667517e-109", | 
|  | "653532977297e-123", | 
|  | "3142213164987e-294", | 
|  | "46202199371337e-072", | 
|  | "231010996856685e-073", | 
|  | "9324754620109615e+212", | 
|  | "78459735791271921e+049", | 
|  | "272104041512242479e+200", | 
|  | "6802601037806061975e+198", | 
|  | "20505426358836677347e-221", | 
|  | "836168422905420598437e-234", | 
|  | "4891559871276714924261e+222", | 
|  |  | 
|  | // Table 2: Stress Inputs for Conversion to 53-bit Binary, > 1/2 ULP | 
|  | "9e-265", | 
|  | "85e-037", | 
|  | "623e+100", | 
|  | "3571e+263", | 
|  | "81661e+153", | 
|  | "920657e-023", | 
|  | "4603285e-024", | 
|  | "87575437e-309", | 
|  | "245540327e+122", | 
|  | "6138508175e+120", | 
|  | "83356057653e+193", | 
|  | "619534293513e+124", | 
|  | "2335141086879e+218", | 
|  | "36167929443327e-159", | 
|  | "609610927149051e-255", | 
|  | "3743626360493413e-165", | 
|  | "94080055902682397e-242", | 
|  | "899810892172646163e+283", | 
|  | "7120190517612959703e+120", | 
|  | "25188282901709339043e-252", | 
|  | "308984926168550152811e-052", | 
|  | "6372891218502368041059e+064", | 
|  |  | 
|  | // Table 14: Stress Inputs for Conversion to 24-bit Binary, <1/2 ULP | 
|  | "5e-20", | 
|  | "67e+14", | 
|  | "985e+15", | 
|  | "7693e-42", | 
|  | "55895e-16", | 
|  | "996622e-44", | 
|  | "7038531e-32", | 
|  | "60419369e-46", | 
|  | "702990899e-20", | 
|  | "6930161142e-48", | 
|  | "25933168707e+13", | 
|  | "596428896559e+20", | 
|  |  | 
|  | // Table 15: Stress Inputs for Conversion to 24-bit Binary, >1/2 ULP | 
|  | "3e-23", | 
|  | "57e+18", | 
|  | "789e-35", | 
|  | "2539e-18", | 
|  | "76173e+28", | 
|  | "887745e-11", | 
|  | "5382571e-37", | 
|  | "82381273e-35", | 
|  | "750486563e-38", | 
|  | "3752432815e-39", | 
|  | "75224575729e-45", | 
|  | "459926601011e+15", | 
|  |  | 
|  | // Constants plundered from strconv/atof_test.go. | 
|  |  | 
|  | "0", | 
|  | "1", | 
|  | "+1", | 
|  | "1e23", | 
|  | "1E23", | 
|  | "100000000000000000000000", | 
|  | "1e-100", | 
|  | "123456700", | 
|  | "99999999999999974834176", | 
|  | "100000000000000000000001", | 
|  | "100000000000000008388608", | 
|  | "100000000000000016777215", | 
|  | "100000000000000016777216", | 
|  | "-1", | 
|  | "-0.1", | 
|  | "-0", // NB: exception made for this input | 
|  | "1e-20", | 
|  | "625e-3", | 
|  |  | 
|  | // largest float64 | 
|  | "1.7976931348623157e308", | 
|  | "-1.7976931348623157e308", | 
|  | // next float64 - too large | 
|  | "1.7976931348623159e308", | 
|  | "-1.7976931348623159e308", | 
|  | // the border is ...158079 | 
|  | // borderline - okay | 
|  | "1.7976931348623158e308", | 
|  | "-1.7976931348623158e308", | 
|  | // borderline - too large | 
|  | "1.797693134862315808e308", | 
|  | "-1.797693134862315808e308", | 
|  |  | 
|  | // a little too large | 
|  | "1e308", | 
|  | "2e308", | 
|  | "1e309", | 
|  |  | 
|  | // way too large | 
|  | "1e310", | 
|  | "-1e310", | 
|  | "1e400", | 
|  | "-1e400", | 
|  | "long:1e400000", | 
|  | "long:-1e400000", | 
|  |  | 
|  | // denormalized | 
|  | "1e-305", | 
|  | "1e-306", | 
|  | "1e-307", | 
|  | "1e-308", | 
|  | "1e-309", | 
|  | "1e-310", | 
|  | "1e-322", | 
|  | // smallest denormal | 
|  | "5e-324", | 
|  | "4e-324", | 
|  | "3e-324", | 
|  | // too small | 
|  | "2e-324", | 
|  | // way too small | 
|  | "1e-350", | 
|  | "long:1e-400000", | 
|  | // way too small, negative | 
|  | "-1e-350", | 
|  | "long:-1e-400000", | 
|  |  | 
|  | // try to overflow exponent | 
|  | // [Disabled: too slow and memory-hungry with rationals.] | 
|  | // "1e-4294967296", | 
|  | // "1e+4294967296", | 
|  | // "1e-18446744073709551616", | 
|  | // "1e+18446744073709551616", | 
|  |  | 
|  | // https://www.exploringbinary.com/java-hangs-when-converting-2-2250738585072012e-308/ | 
|  | "2.2250738585072012e-308", | 
|  | // https://www.exploringbinary.com/php-hangs-on-numeric-value-2-2250738585072011e-308/ | 
|  | "2.2250738585072011e-308", | 
|  |  | 
|  | // A very large number (initially wrongly parsed by the fast algorithm). | 
|  | "4.630813248087435e+307", | 
|  |  | 
|  | // A different kind of very large number. | 
|  | "22.222222222222222", | 
|  | "long:2." + strings.Repeat("2", 4000) + "e+1", | 
|  |  | 
|  | // Exactly halfway between 1 and math.Nextafter(1, 2). | 
|  | // Round to even (down). | 
|  | "1.00000000000000011102230246251565404236316680908203125", | 
|  | // Slightly lower; still round down. | 
|  | "1.00000000000000011102230246251565404236316680908203124", | 
|  | // Slightly higher; round up. | 
|  | "1.00000000000000011102230246251565404236316680908203126", | 
|  | // Slightly higher, but you have to read all the way to the end. | 
|  | "long:1.00000000000000011102230246251565404236316680908203125" + strings.Repeat("0", 10000) + "1", | 
|  |  | 
|  | // Smallest denormal, 2^(-1022-52) | 
|  | "4.940656458412465441765687928682213723651e-324", | 
|  | // Half of smallest denormal, 2^(-1022-53) | 
|  | "2.470328229206232720882843964341106861825e-324", | 
|  | // A little more than the exact half of smallest denormal | 
|  | // 2^-1075 + 2^-1100.  (Rounds to 1p-1074.) | 
|  | "2.470328302827751011111470718709768633275e-324", | 
|  | // The exact halfway between smallest normal and largest denormal: | 
|  | // 2^-1022 - 2^-1075.  (Rounds to 2^-1022.) | 
|  | "2.225073858507201136057409796709131975935e-308", | 
|  |  | 
|  | "1152921504606846975",  //   1<<60 - 1 | 
|  | "-1152921504606846975", // -(1<<60 - 1) | 
|  | "1152921504606846977",  //   1<<60 + 1 | 
|  | "-1152921504606846977", // -(1<<60 + 1) | 
|  |  | 
|  | "1/3", | 
|  | } | 
|  |  | 
|  | // isFinite reports whether f represents a finite rational value. | 
|  | // It is equivalent to !math.IsNan(f) && !math.IsInf(f, 0). | 
|  | func isFinite(f float64) bool { | 
|  | return math.Abs(f) <= math.MaxFloat64 | 
|  | } | 
|  |  | 
|  | func TestFloat32SpecialCases(t *testing.T) { | 
|  | for _, input := range float64inputs { | 
|  | if strings.HasPrefix(input, "long:") { | 
|  | if !*long { | 
|  | continue | 
|  | } | 
|  | input = input[len("long:"):] | 
|  | } | 
|  |  | 
|  | r, ok := new(Rat).SetString(input) | 
|  | if !ok { | 
|  | t.Errorf("Rat.SetString(%q) failed", input) | 
|  | continue | 
|  | } | 
|  | f, exact := r.Float32() | 
|  |  | 
|  | // 1. Check string -> Rat -> float32 conversions are | 
|  | // consistent with strconv.ParseFloat. | 
|  | // Skip this check if the input uses "a/b" rational syntax. | 
|  | if !strings.Contains(input, "/") { | 
|  | e64, _ := strconv.ParseFloat(input, 32) | 
|  | e := float32(e64) | 
|  |  | 
|  | // Careful: negative Rats too small for | 
|  | // float64 become -0, but Rat obviously cannot | 
|  | // preserve the sign from SetString("-0"). | 
|  | switch { | 
|  | case math.Float32bits(e) == math.Float32bits(f): | 
|  | // Ok: bitwise equal. | 
|  | case f == 0 && r.Num().BitLen() == 0: | 
|  | // Ok: Rat(0) is equivalent to both +/- float64(0). | 
|  | default: | 
|  | t.Errorf("strconv.ParseFloat(%q) = %g (%b), want %g (%b); delta = %g", input, e, e, f, f, f-e) | 
|  | } | 
|  | } | 
|  |  | 
|  | if !isFinite(float64(f)) { | 
|  | continue | 
|  | } | 
|  |  | 
|  | // 2. Check f is best approximation to r. | 
|  | if !checkIsBestApprox32(t, f, r) { | 
|  | // Append context information. | 
|  | t.Errorf("(input was %q)", input) | 
|  | } | 
|  |  | 
|  | // 3. Check f->R->f roundtrip is non-lossy. | 
|  | checkNonLossyRoundtrip32(t, f) | 
|  |  | 
|  | // 4. Check exactness using slow algorithm. | 
|  | if wasExact := new(Rat).SetFloat64(float64(f)).Cmp(r) == 0; wasExact != exact { | 
|  | t.Errorf("Rat.SetString(%q).Float32().exact = %t, want %t", input, exact, wasExact) | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | func TestFloat64SpecialCases(t *testing.T) { | 
|  | for _, input := range float64inputs { | 
|  | if strings.HasPrefix(input, "long:") { | 
|  | if !*long { | 
|  | continue | 
|  | } | 
|  | input = input[len("long:"):] | 
|  | } | 
|  |  | 
|  | r, ok := new(Rat).SetString(input) | 
|  | if !ok { | 
|  | t.Errorf("Rat.SetString(%q) failed", input) | 
|  | continue | 
|  | } | 
|  | f, exact := r.Float64() | 
|  |  | 
|  | // 1. Check string -> Rat -> float64 conversions are | 
|  | // consistent with strconv.ParseFloat. | 
|  | // Skip this check if the input uses "a/b" rational syntax. | 
|  | if !strings.Contains(input, "/") { | 
|  | e, _ := strconv.ParseFloat(input, 64) | 
|  |  | 
|  | // Careful: negative Rats too small for | 
|  | // float64 become -0, but Rat obviously cannot | 
|  | // preserve the sign from SetString("-0"). | 
|  | switch { | 
|  | case math.Float64bits(e) == math.Float64bits(f): | 
|  | // Ok: bitwise equal. | 
|  | case f == 0 && r.Num().BitLen() == 0: | 
|  | // Ok: Rat(0) is equivalent to both +/- float64(0). | 
|  | default: | 
|  | t.Errorf("strconv.ParseFloat(%q) = %g (%b), want %g (%b); delta = %g", input, e, e, f, f, f-e) | 
|  | } | 
|  | } | 
|  |  | 
|  | if !isFinite(f) { | 
|  | continue | 
|  | } | 
|  |  | 
|  | // 2. Check f is best approximation to r. | 
|  | if !checkIsBestApprox64(t, f, r) { | 
|  | // Append context information. | 
|  | t.Errorf("(input was %q)", input) | 
|  | } | 
|  |  | 
|  | // 3. Check f->R->f roundtrip is non-lossy. | 
|  | checkNonLossyRoundtrip64(t, f) | 
|  |  | 
|  | // 4. Check exactness using slow algorithm. | 
|  | if wasExact := new(Rat).SetFloat64(f).Cmp(r) == 0; wasExact != exact { | 
|  | t.Errorf("Rat.SetString(%q).Float64().exact = %t, want %t", input, exact, wasExact) | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | func TestIssue31184(t *testing.T) { | 
|  | var x Rat | 
|  | for _, want := range []string{ | 
|  | "-213.090", | 
|  | "8.192", | 
|  | "16.000", | 
|  | } { | 
|  | x.SetString(want) | 
|  | got := x.FloatString(3) | 
|  | if got != want { | 
|  | t.Errorf("got %s, want %s", got, want) | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | func TestIssue45910(t *testing.T) { | 
|  | var x Rat | 
|  | for _, test := range []struct { | 
|  | input string | 
|  | want  bool | 
|  | }{ | 
|  | {"1e-1000001", false}, | 
|  | {"1e-1000000", true}, | 
|  | {"1e+1000000", true}, | 
|  | {"1e+1000001", false}, | 
|  |  | 
|  | {"0p1000000000000", true}, | 
|  | {"1p-10000001", false}, | 
|  | {"1p-10000000", true}, | 
|  | {"1p+10000000", true}, | 
|  | {"1p+10000001", false}, | 
|  | {"1.770p02041010010011001001", false}, // test case from issue | 
|  | } { | 
|  | _, got := x.SetString(test.input) | 
|  | if got != test.want { | 
|  | t.Errorf("SetString(%s) got ok = %v; want %v", test.input, got, test.want) | 
|  | } | 
|  | } | 
|  | } | 
|  | func TestFloatPrec(t *testing.T) { | 
|  | var tests = []struct { | 
|  | f    string | 
|  | prec int | 
|  | ok   bool | 
|  | fdec string | 
|  | }{ | 
|  | // examples from the issue #50489 | 
|  | {"10/100", 1, true, "0.1"}, | 
|  | {"3/100", 2, true, "0.03"}, | 
|  | {"10", 0, true, "10"}, | 
|  |  | 
|  | // more examples | 
|  | {"zero", 0, true, "0"},      // test uninitialized zero value for Rat | 
|  | {"0", 0, true, "0"},         // 0 | 
|  | {"1", 0, true, "1"},         // 1 | 
|  | {"1/2", 1, true, "0.5"},     // 0.5 | 
|  | {"1/3", 0, false, "0"},      // 0.(3) | 
|  | {"1/4", 2, true, "0.25"},    // 0.25 | 
|  | {"1/5", 1, true, "0.2"},     // 0.2 | 
|  | {"1/6", 1, false, "0.2"},    // 0.1(6) | 
|  | {"1/7", 0, false, "0"},      // 0.(142857) | 
|  | {"1/8", 3, true, "0.125"},   // 0.125 | 
|  | {"1/9", 0, false, "0"},      // 0.(1) | 
|  | {"1/10", 1, true, "0.1"},    // 0.1 | 
|  | {"1/11", 0, false, "0"},     // 0.(09) | 
|  | {"1/12", 2, false, "0.08"},  // 0.08(3) | 
|  | {"1/13", 0, false, "0"},     // 0.(076923) | 
|  | {"1/14", 1, false, "0.1"},   // 0.0(714285) | 
|  | {"1/15", 1, false, "0.1"},   // 0.0(6) | 
|  | {"1/16", 4, true, "0.0625"}, // 0.0625 | 
|  |  | 
|  | {"10/2", 0, true, "5"},                    // 5 | 
|  | {"10/3", 0, false, "3"},                   // 3.(3) | 
|  | {"10/6", 0, false, "2"},                   // 1.(6) | 
|  | {"1/10000000", 7, true, "0.0000001"},      // 0.0000001 | 
|  | {"1/3125", 5, true, "0.00032"},            // "0.00032" | 
|  | {"1/1024", 10, true, "0.0009765625"},      // 0.0009765625 | 
|  | {"1/304000", 7, false, "0.0000033"},       // 0.0000032(894736842105263157) | 
|  | {"1/48828125", 11, true, "0.00000002048"}, // 0.00000002048 | 
|  | } | 
|  |  | 
|  | for _, test := range tests { | 
|  | var f Rat | 
|  |  | 
|  | // check uninitialized zero value | 
|  | if test.f != "zero" { | 
|  | _, ok := f.SetString(test.f) | 
|  | if !ok { | 
|  | t.Fatalf("invalid test case: f = %s", test.f) | 
|  | } | 
|  | } | 
|  |  | 
|  | // results for f and -f must be the same | 
|  | fdec := test.fdec | 
|  | for i := 0; i < 2; i++ { | 
|  | prec, ok := f.FloatPrec() | 
|  | if prec != test.prec || ok != test.ok { | 
|  | t.Errorf("%s: FloatPrec(%s): got prec, ok = %d, %v; want %d, %v", test.f, &f, prec, ok, test.prec, test.ok) | 
|  | } | 
|  | s := f.FloatString(test.prec) | 
|  | if s != fdec { | 
|  | t.Errorf("%s: FloatString(%s, %d): got %s; want %s", test.f, &f, prec, s, fdec) | 
|  | } | 
|  | // proceed with -f but don't add a "-" before a "0" | 
|  | if f.Sign() > 0 { | 
|  | f.Neg(&f) | 
|  | fdec = "-" + fdec | 
|  | } | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | func BenchmarkFloatPrecExact(b *testing.B) { | 
|  | for _, n := range []int{1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6} { | 
|  | // d := 5^n | 
|  | d := NewInt(5) | 
|  | p := NewInt(int64(n)) | 
|  | d.Exp(d, p, nil) | 
|  |  | 
|  | // r := 1/d | 
|  | var r Rat | 
|  | r.SetFrac(NewInt(1), d) | 
|  |  | 
|  | b.Run(fmt.Sprint(n), func(b *testing.B) { | 
|  | for i := 0; i < b.N; i++ { | 
|  | prec, ok := r.FloatPrec() | 
|  | if prec != n || !ok { | 
|  | b.Fatalf("got exact, ok = %d, %v; want %d, %v", prec, ok, uint64(n), true) | 
|  | } | 
|  | } | 
|  | }) | 
|  | } | 
|  | } | 
|  |  | 
|  | func BenchmarkFloatPrecMixed(b *testing.B) { | 
|  | for _, n := range []int{1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6} { | 
|  | // d := (3·5·7·11)^n | 
|  | d := NewInt(3 * 5 * 7 * 11) | 
|  | p := NewInt(int64(n)) | 
|  | d.Exp(d, p, nil) | 
|  |  | 
|  | // r := 1/d | 
|  | var r Rat | 
|  | r.SetFrac(NewInt(1), d) | 
|  |  | 
|  | b.Run(fmt.Sprint(n), func(b *testing.B) { | 
|  | for i := 0; i < b.N; i++ { | 
|  | prec, ok := r.FloatPrec() | 
|  | if prec != n || ok { | 
|  | b.Fatalf("got exact, ok = %d, %v; want %d, %v", prec, ok, uint64(n), false) | 
|  | } | 
|  | } | 
|  | }) | 
|  | } | 
|  | } | 
|  |  | 
|  | func BenchmarkFloatPrecInexact(b *testing.B) { | 
|  | for _, n := range []int{1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6} { | 
|  | // d := 5^n + 1 | 
|  | d := NewInt(5) | 
|  | p := NewInt(int64(n)) | 
|  | d.Exp(d, p, nil) | 
|  | d.Add(d, NewInt(1)) | 
|  |  | 
|  | // r := 1/d | 
|  | var r Rat | 
|  | r.SetFrac(NewInt(1), d) | 
|  |  | 
|  | b.Run(fmt.Sprint(n), func(b *testing.B) { | 
|  | for i := 0; i < b.N; i++ { | 
|  | _, ok := r.FloatPrec() | 
|  | if ok { | 
|  | b.Fatalf("got unexpected ok") | 
|  | } | 
|  | } | 
|  | }) | 
|  | } | 
|  | } |