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-rw-r--r--src/math/big/ratconv_test.go616
1 files changed, 616 insertions, 0 deletions
diff --git a/src/math/big/ratconv_test.go b/src/math/big/ratconv_test.go
new file mode 100644
index 0000000..15d206c
--- /dev/null
+++ b/src/math/big/ratconv_test.go
@@ -0,0 +1,616 @@
+// 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"
+ "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/"},
+
+ // 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 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)
+ }
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-09-25 21:22:51 +0000