mirror of git://gcc.gnu.org/git/gcc.git
75 lines
2.0 KiB
Go
75 lines
2.0 KiB
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// This file implements encoding/decoding of Ints.
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package big
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import "fmt"
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// Gob codec version. Permits backward-compatible changes to the encoding.
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const intGobVersion byte = 1
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// GobEncode implements the gob.GobEncoder interface.
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func (x *Int) GobEncode() ([]byte, error) {
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if x == nil {
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return nil, nil
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}
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buf := make([]byte, 1+len(x.abs)*_S) // extra byte for version and sign bit
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i := x.abs.bytes(buf) - 1 // i >= 0
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b := intGobVersion << 1 // make space for sign bit
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if x.neg {
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b |= 1
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}
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buf[i] = b
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return buf[i:], nil
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}
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// GobDecode implements the gob.GobDecoder interface.
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func (z *Int) GobDecode(buf []byte) error {
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if len(buf) == 0 {
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// Other side sent a nil or default value.
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*z = Int{}
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return nil
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}
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b := buf[0]
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if b>>1 != intGobVersion {
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return fmt.Errorf("Int.GobDecode: encoding version %d not supported", b>>1)
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}
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z.neg = b&1 != 0
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z.abs = z.abs.setBytes(buf[1:])
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return nil
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}
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// MarshalText implements the encoding.TextMarshaler interface.
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func (x *Int) MarshalText() (text []byte, err error) {
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if x == nil {
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return []byte("<nil>"), nil
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}
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return x.abs.itoa(x.neg, 10), nil
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}
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// UnmarshalText implements the encoding.TextUnmarshaler interface.
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func (z *Int) UnmarshalText(text []byte) error {
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// TODO(gri): get rid of the []byte/string conversion
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if _, ok := z.SetString(string(text), 0); !ok {
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return fmt.Errorf("math/big: cannot unmarshal %q into a *big.Int", text)
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}
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return nil
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}
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// The JSON marshallers are only here for API backward compatibility
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// (programs that explicitly look for these two methods). JSON works
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// fine with the TextMarshaler only.
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// MarshalJSON implements the json.Marshaler interface.
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func (x *Int) MarshalJSON() ([]byte, error) {
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return x.MarshalText()
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}
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// UnmarshalJSON implements the json.Unmarshaler interface.
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func (z *Int) UnmarshalJSON(text []byte) error {
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return z.UnmarshalText(text)
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}
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