neo-go/pkg/util/fixed8.go
Evgeniy Kulikov 6ccb518ab0 Optimizations + some improvements (#105)
* Optimizations + some improvements

- optimized pkg/core/storage.HeaderHashes
- optimized pkg/rpc.performRequest (used json.Encoder)
- fixes for pkg/util.ReadVarUint and pkg/util.WriteVarUint
- optimized and fix fixed8 (Fixed8DecodeString / MarshalJSON) + tests
- optimized and fix uint160 (Bytes / Uint160DecodeString / Equal / MarshalJSON) + tests
- optimized and fix uint256 (Bytes / Equal / MarshalJSON) + tests
- preallocate for pkg/vm.buildStackOutput
- add go.mod / go.sum

* update version
2018-11-26 16:56:45 +01:00

100 lines
2.1 KiB
Go

package util
import (
"encoding/json"
"errors"
"strconv"
"strings"
)
const (
precision = 8
decimals = 100000000
)
var errInvalidString = errors.New("Fixed8 must satisfy following regex \\d+(\\.\\d{1,8})?")
// Fixed8 represents a fixed-point number with precision 10^-8.
type Fixed8 int64
// String implements the Stringer interface.
func (f Fixed8) String() string {
buf := new(strings.Builder)
val := int64(f)
if val < 0 {
buf.WriteRune('-')
val = -val
}
str := strconv.FormatInt(val/decimals, 10)
buf.WriteString(str)
val %= decimals
if val > 0 {
buf.WriteRune('.')
str = strconv.FormatInt(val, 10)
for i := len(str); i < 8; i++ {
buf.WriteRune('0')
}
buf.WriteString(str)
}
return buf.String()
}
// Value returns the original value representing the Fixed8.
func (f Fixed8) Value() int64 {
return int64(f) / int64(decimals)
}
// NewFixed8 return a new Fixed8 type multiplied by decimals.
func NewFixed8(val int) Fixed8 {
return Fixed8(decimals * val)
}
// Fixed8DecodeString parses s which must be a fixed point number
// with precision up to 10^-8
func Fixed8DecodeString(s string) (Fixed8, error) {
parts := strings.SplitN(s, ".", 2)
ip, err := strconv.ParseInt(parts[0], 10, 64)
if err != nil {
return 0, errInvalidString
} else if len(parts) == 1 {
return Fixed8(ip * decimals), nil
}
fp, err := strconv.ParseInt(parts[1], 10, 64)
if err != nil || fp >= decimals {
return 0, errInvalidString
}
for i := len(parts[1]); i < precision; i++ {
fp *= 10
}
if ip < 0 {
return Fixed8(ip*decimals - fp), nil
}
return Fixed8(ip*decimals + fp), nil
}
// UnmarshalJSON implements the json unmarshaller interface.
func (f *Fixed8) UnmarshalJSON(data []byte) error {
var s string
if err := json.Unmarshal(data, &s); err == nil {
p, err := Fixed8DecodeString(s)
if err != nil {
return err
}
*f = p
return nil
}
var fl float64
if err := json.Unmarshal(data, &fl); err != nil {
return err
}
*f = Fixed8(decimals * fl)
return nil
}
// MarshalJSON implements the json marshaller interface.
func (f Fixed8) MarshalJSON() ([]byte, error) {
return []byte(`"` + f.String() + `"`), nil
}