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fixed64.go
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fixed64.go
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package common
import (
"bytes"
"encoding/binary"
"errors"
"io"
"strconv"
"strings"
)
//the 64 bit fixed-point number, precise 10^-8
type Fixed64 int64
func (f *Fixed64) Serialize(w io.Writer) error {
err := binary.Write(w, binary.LittleEndian, int64(*f))
if err != nil {
return err
}
return nil
}
func (f *Fixed64) Deserialize(r io.Reader) error {
p := make([]byte, 8)
n, err := r.Read(p)
if n <= 0 || err != nil {
return err
}
buf := bytes.NewBuffer(p)
var x int64
err = binary.Read(buf, binary.LittleEndian, &x)
if err != nil {
return err
}
*f = Fixed64(x)
return nil
}
func (f Fixed64) IntValue() int64 {
return int64(f)
}
func (f Fixed64) String() string {
var buff bytes.Buffer
value := uint64(f)
if f < 0 {
buff.WriteRune('-')
value = uint64(-f)
}
buff.WriteString(strconv.FormatUint(value/100000000, 10))
value %= 100000000
if value > 0 {
buff.WriteRune('.')
s := strconv.FormatUint(value, 10)
for i := len(s); i < 8; i++ {
buff.WriteRune('0')
}
buff.WriteString(s)
}
return buff.String()
}
func (f *Fixed64) Bytes() ([]byte, error) {
buf := new(bytes.Buffer)
err := f.Serialize(buf)
if err != nil {
return nil, err
}
return buf.Bytes(), nil
}
func Fixed64FromBytes(value []byte) (*Fixed64, error) {
var fixed64 Fixed64
err := fixed64.Deserialize(bytes.NewReader(value))
if err != nil {
return nil, err
}
return &fixed64, nil
}
func StringToFixed64(s string) (*Fixed64, error) {
var buffer bytes.Buffer
//TODO: check invalid string
di := strings.Index(s, ".")
if len(s)-di > 9 {
return nil, errors.New("unsupported precision")
}
if di == -1 {
buffer.WriteString(s)
for i := 0; i < 8; i++ {
buffer.WriteByte('0')
}
} else {
buffer.WriteString(s[:di])
buffer.WriteString(s[di+1:])
n := 8 - (len(s) - di - 1)
for i := 0; i < n; i++ {
buffer.WriteByte('0')
}
}
r, err := strconv.ParseInt(buffer.String(), 10, 64)
if err != nil {
return nil, err
}
value := Fixed64(r)
return &value, nil
}