--- /dev/null
+// 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_test
+
+import (
+ "cmd/compile/internal/big"
+ "fmt"
+)
+
+// Use the classic continued fraction for e
+// e = [1; 0, 1, 1, 2, 1, 1, ... 2n, 1, 1, ...]
+// i.e., for the nth term, use
+// 1 if n mod 3 != 1
+// (n-1)/3 * 2 if n mod 3 == 1
+func recur(n, lim int64) *big.Rat {
+ term := new(big.Rat)
+ if n%3 != 1 {
+ term.SetInt64(1)
+ } else {
+ term.SetInt64((n - 1) / 3 * 2)
+ }
+
+ if n > lim {
+ return term
+ }
+
+ // Directly initialize frac as the fractional
+ // inverse of the result of recur.
+ frac := new(big.Rat).Inv(recur(n+1, lim))
+
+ return term.Add(term, frac)
+}
+
+// This example demonstrates how to use big.Rat to compute the
+// first 15 terms in the sequence of rational convergents for
+// the constant e (base of natural logarithm).
+func Example_eConvergents() {
+ for i := 1; i <= 15; i++ {
+ r := recur(0, int64(i))
+
+ // Print r both as a fraction and as a floating-point number.
+ // Since big.Rat implements fmt.Formatter, we can use %-13s to
+ // get a left-aligned string representation of the fraction.
+ fmt.Printf("%-13s = %s\n", r, r.FloatString(8))
+ }
+
+ // Output:
+ // 2/1 = 2.00000000
+ // 3/1 = 3.00000000
+ // 8/3 = 2.66666667
+ // 11/4 = 2.75000000
+ // 19/7 = 2.71428571
+ // 87/32 = 2.71875000
+ // 106/39 = 2.71794872
+ // 193/71 = 2.71830986
+ // 1264/465 = 2.71827957
+ // 1457/536 = 2.71828358
+ // 2721/1001 = 2.71828172
+ // 23225/8544 = 2.71828184
+ // 25946/9545 = 2.71828182
+ // 49171/18089 = 2.71828183
+ // 517656/190435 = 2.71828183
+}
--- /dev/null
+// 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.
+
+// This file implements encoding/decoding of Floats.
+
+package big
+
+import "fmt"
+
+// MarshalText implements the encoding.TextMarshaler interface.
+// Only the Float value is marshaled (in full precision), other
+// attributes such as precision or accuracy are ignored.
+func (x *Float) MarshalText() (text []byte, err error) {
+ if x == nil {
+ return []byte("<nil>"), nil
+ }
+ var buf []byte
+ return x.Append(buf, 'g', -1), nil
+}
+
+// UnmarshalText implements the encoding.TextUnmarshaler interface.
+// The result is rounded per the precision and rounding mode of z.
+// If z's precision is 0, it is changed to 64 before rounding takes
+// effect.
+func (z *Float) UnmarshalText(text []byte) error {
+ // TODO(gri): get rid of the []byte/string conversion
+ _, _, err := z.Parse(string(text), 0)
+ if err != nil {
+ err = fmt.Errorf("math/big: cannot unmarshal %q into a *big.Float (%v)", text, err)
+ }
+ return err
+}
--- /dev/null
+// 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 (
+ "encoding/json"
+ "testing"
+)
+
+var floatVals = []string{
+ "0",
+ "1",
+ "0.1",
+ "2.71828",
+ "1234567890",
+ "3.14e1234",
+ "3.14e-1234",
+ "0.738957395793475734757349579759957975985497e100",
+ "0.73895739579347546656564656573475734957975995797598589749859834759476745986795497e100",
+ "inf",
+ "Inf",
+}
+
+func TestFloatJSONEncoding(t *testing.T) {
+ for _, test := range floatVals {
+ for _, sign := range []string{"", "+", "-"} {
+ for _, prec := range []uint{0, 1, 2, 10, 53, 64, 100, 1000} {
+ x := sign + test
+ var tx Float
+ _, _, err := tx.SetPrec(prec).Parse(x, 0)
+ if err != nil {
+ t.Errorf("parsing of %s (prec = %d) failed (invalid test case): %v", x, prec, err)
+ continue
+ }
+ b, err := json.Marshal(&tx)
+ if err != nil {
+ t.Errorf("marshaling of %v (prec = %d) failed: %v", &tx, prec, err)
+ continue
+ }
+ var rx Float
+ rx.SetPrec(prec)
+ if err := json.Unmarshal(b, &rx); err != nil {
+ t.Errorf("unmarshaling of %v (prec = %d) failed: %v", &tx, prec, err)
+ continue
+ }
+ if rx.Cmp(&tx) != 0 {
+ t.Errorf("JSON encoding of %v (prec = %d) failed: got %v want %v", &tx, prec, &rx, &tx)
+ }
+ }
+ }
+ }
+}
--- /dev/null
+// 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.
+
+// This file implements encoding/decoding of Ints.
+
+package big
+
+import "fmt"
+
+// Gob codec version. Permits backward-compatible changes to the encoding.
+const intGobVersion byte = 1
+
+// GobEncode implements the gob.GobEncoder interface.
+func (x *Int) GobEncode() ([]byte, error) {
+ if x == nil {
+ return nil, nil
+ }
+ buf := make([]byte, 1+len(x.abs)*_S) // extra byte for version and sign bit
+ i := x.abs.bytes(buf) - 1 // i >= 0
+ b := intGobVersion << 1 // make space for sign bit
+ if x.neg {
+ b |= 1
+ }
+ buf[i] = b
+ return buf[i:], nil
+}
+
+// GobDecode implements the gob.GobDecoder interface.
+func (z *Int) GobDecode(buf []byte) error {
+ if len(buf) == 0 {
+ // Other side sent a nil or default value.
+ *z = Int{}
+ return nil
+ }
+ b := buf[0]
+ if b>>1 != intGobVersion {
+ return fmt.Errorf("Int.GobDecode: encoding version %d not supported", b>>1)
+ }
+ z.neg = b&1 != 0
+ z.abs = z.abs.setBytes(buf[1:])
+ return nil
+}
+
+// MarshalText implements the encoding.TextMarshaler interface.
+func (x *Int) MarshalText() (text []byte, err error) {
+ if x == nil {
+ return []byte("<nil>"), nil
+ }
+ return x.abs.itoa(x.neg, 10), nil
+}
+
+// UnmarshalText implements the encoding.TextUnmarshaler interface.
+func (z *Int) UnmarshalText(text []byte) error {
+ // TODO(gri): get rid of the []byte/string conversion
+ if _, ok := z.SetString(string(text), 0); !ok {
+ return fmt.Errorf("math/big: cannot unmarshal %q into a *big.Int", text)
+ }
+ return nil
+}
+
+// The JSON marshallers are only here for API backward compatibility
+// (programs that explicitly look for these two methods). JSON works
+// fine with the TextMarshaler only.
+
+// MarshalJSON implements the json.Marshaler interface.
+func (x *Int) MarshalJSON() ([]byte, error) {
+ return x.MarshalText()
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface.
+func (z *Int) UnmarshalJSON(text []byte) error {
+ return z.UnmarshalText(text)
+}
--- /dev/null
+// 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"
+ "encoding/gob"
+ "encoding/json"
+ "encoding/xml"
+ "testing"
+)
+
+var encodingTests = []string{
+ "0",
+ "1",
+ "2",
+ "10",
+ "1000",
+ "1234567890",
+ "298472983472983471903246121093472394872319615612417471234712061",
+}
+
+func TestIntGobEncoding(t *testing.T) {
+ var medium bytes.Buffer
+ enc := gob.NewEncoder(&medium)
+ dec := gob.NewDecoder(&medium)
+ for _, test := range encodingTests {
+ for _, sign := range []string{"", "+", "-"} {
+ x := sign + test
+ medium.Reset() // empty buffer for each test case (in case of failures)
+ var tx Int
+ tx.SetString(x, 10)
+ if err := enc.Encode(&tx); err != nil {
+ t.Errorf("encoding of %s failed: %s", &tx, err)
+ continue
+ }
+ var rx Int
+ if err := dec.Decode(&rx); err != nil {
+ t.Errorf("decoding of %s failed: %s", &tx, err)
+ continue
+ }
+ 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.Fatalf("transmission of (*Int)(nil) failed: got %s want 0", out)
+ }
+}
+
+func TestIntJSONEncoding(t *testing.T) {
+ for _, test := range encodingTests {
+ for _, sign := range []string{"", "+", "-"} {
+ x := sign + test
+ var tx Int
+ tx.SetString(x, 10)
+ 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 TestIntXMLEncoding(t *testing.T) {
+ for _, test := range encodingTests {
+ for _, sign := range []string{"", "+", "-"} {
+ x := sign + test
+ var tx Int
+ tx.SetString(x, 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)
+ }
+ }
+ }
+}
--- /dev/null
+// 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.
+
+// This file implements encoding/decoding of Rats.
+
+package big
+
+import (
+ "encoding/binary"
+ "errors"
+ "fmt"
+)
+
+// Gob codec version. Permits backward-compatible changes to the encoding.
+const ratGobVersion byte = 1
+
+// GobEncode implements the gob.GobEncoder interface.
+func (x *Rat) GobEncode() ([]byte, error) {
+ if x == nil {
+ return nil, nil
+ }
+ buf := make([]byte, 1+4+(len(x.a.abs)+len(x.b.abs))*_S) // extra bytes for version and sign bit (1), and numerator length (4)
+ i := x.b.abs.bytes(buf)
+ j := x.a.abs.bytes(buf[:i])
+ n := i - j
+ if int(uint32(n)) != n {
+ // this should never happen
+ return nil, errors.New("Rat.GobEncode: numerator too large")
+ }
+ binary.BigEndian.PutUint32(buf[j-4:j], uint32(n))
+ j -= 1 + 4
+ b := ratGobVersion << 1 // make space for sign bit
+ if x.a.neg {
+ b |= 1
+ }
+ buf[j] = b
+ return buf[j:], nil
+}
+
+// GobDecode implements the gob.GobDecoder interface.
+func (z *Rat) GobDecode(buf []byte) error {
+ if len(buf) == 0 {
+ // Other side sent a nil or default value.
+ *z = Rat{}
+ return nil
+ }
+ b := buf[0]
+ if b>>1 != ratGobVersion {
+ return fmt.Errorf("Rat.GobDecode: encoding version %d not supported", b>>1)
+ }
+ const j = 1 + 4
+ i := j + binary.BigEndian.Uint32(buf[j-4:j])
+ z.a.neg = b&1 != 0
+ z.a.abs = z.a.abs.setBytes(buf[j:i])
+ z.b.abs = z.b.abs.setBytes(buf[i:])
+ return nil
+}
+
+// MarshalText implements the encoding.TextMarshaler interface.
+func (x *Rat) MarshalText() (text []byte, err error) {
+ // TODO(gri): get rid of the []byte/string conversion
+ return []byte(x.RatString()), nil
+}
+
+// UnmarshalText implements the encoding.TextUnmarshaler interface.
+func (z *Rat) UnmarshalText(text []byte) error {
+ // TODO(gri): get rid of the []byte/string conversion
+ if _, ok := z.SetString(string(text)); !ok {
+ return fmt.Errorf("math/big: cannot unmarshal %q into a *big.Rat", text)
+ }
+ return nil
+}
--- /dev/null
+// 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"
+ "encoding/gob"
+ "encoding/json"
+ "encoding/xml"
+ "testing"
+)
+
+func TestRatGobEncoding(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 Rat
+ tx.SetString(test + ".14159265")
+ if err := enc.Encode(&tx); err != nil {
+ t.Errorf("encoding of %s failed: %s", &tx, err)
+ continue
+ }
+ var rx Rat
+ if err := dec.Decode(&rx); err != nil {
+ t.Errorf("decoding of %s failed: %s", &tx, err)
+ continue
+ }
+ if rx.Cmp(&tx) != 0 {
+ t.Errorf("transmission of %s failed: got %s want %s", &tx, &rx, &tx)
+ }
+ }
+}
+
+// Sending a nil Rat pointer (inside a slice) on a round trip through gob should yield a zero.
+// TODO: top-level nils.
+func TestGobEncodingNilRatInSlice(t *testing.T) {
+ buf := new(bytes.Buffer)
+ enc := gob.NewEncoder(buf)
+ dec := gob.NewDecoder(buf)
+
+ var in = make([]*Rat, 1)
+ err := enc.Encode(&in)
+ if err != nil {
+ t.Errorf("gob encode failed: %q", err)
+ }
+ var out []*Rat
+ 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 Rat
+ if out[0].Cmp(&zero) != 0 {
+ t.Fatalf("transmission of (*Int)(nil) failed: got %s want 0", out)
+ }
+}
+
+var ratNums = []string{
+ "-141592653589793238462643383279502884197169399375105820974944592307816406286",
+ "-1415926535897932384626433832795028841971",
+ "-141592653589793",
+ "-1",
+ "0",
+ "1",
+ "141592653589793",
+ "1415926535897932384626433832795028841971",
+ "141592653589793238462643383279502884197169399375105820974944592307816406286",
+}
+
+var ratDenoms = []string{
+ "1",
+ "718281828459045",
+ "7182818284590452353602874713526624977572",
+ "718281828459045235360287471352662497757247093699959574966967627724076630353",
+}
+
+func TestRatJSONEncoding(t *testing.T) {
+ for _, num := range ratNums {
+ for _, denom := range ratDenoms {
+ var tx Rat
+ tx.SetString(num + "/" + denom)
+ b, err := json.Marshal(&tx)
+ if err != nil {
+ t.Errorf("marshaling of %s failed: %s", &tx, err)
+ continue
+ }
+ var rx Rat
+ 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 TestRatXMLEncoding(t *testing.T) {
+ for _, num := range ratNums {
+ for _, denom := range ratDenoms {
+ var tx Rat
+ tx.SetString(num + "/" + denom)
+ b, err := xml.Marshal(&tx)
+ if err != nil {
+ t.Errorf("marshaling of %s failed: %s", &tx, err)
+ continue
+ }
+ var rx Rat
+ 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)
+ }
+ }
+ }
+}