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fixed_size.go
160 lines (135 loc) · 3.46 KB
/
fixed_size.go
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//
// Copyright 2019 Insolar Technologies GmbH
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
package longbits
import (
"bytes"
"io"
)
type Foldable interface {
FoldToUint64() uint64
}
//go:generate minimock -i github.com/insolar/insolar/longbits.FixedReader -o . -s _mock.go -g
type FixedReader interface {
io.WriterTo
io.Reader
AsBytes() []byte
AsByteString() ByteString
FixedByteSize() int
}
//go:generate minimock -i github.com/insolar/insolar/longbits.FoldableReader -o . -s _mock.go -g
type FoldableReader interface {
FixedReader
Foldable
}
func FoldUint64(v uint64) uint32 {
return uint32(v) ^ uint32(v>>32)
}
func EqualFixedLenWriterTo(t, o FixedReader) bool {
if t == FixedReader(nil) || o == FixedReader(nil) {
return false
}
return (&writerToComparer{}).compare(t, o)
}
type writerToComparer struct {
thisValue *[]byte
other io.WriterTo
result bool
}
func (c *writerToComparer) compare(this, other FixedReader) bool {
c.thisValue = nil
if this == nil || other == nil || this.FixedByteSize() != other.FixedByteSize() {
return false
}
c.other = other
_, _ = this.WriteTo(c)
return c.other == nil && c.result
}
func (c *writerToComparer) Write(otherValue []byte) (int, error) {
if c.other == nil {
panic("content of FixedReader must be read/written all at once")
}
if c.thisValue == nil {
c.thisValue = &otherValue // result of &var is never nil
_, err := c.other.WriteTo(c)
if err != nil {
return 0, err
}
} else {
c.other = nil // mark "done"
c.result = bytes.Equal(*c.thisValue, otherValue)
}
return len(otherValue), nil
}
type fixedSize struct {
data []byte
}
func (c *fixedSize) AsByteString() ByteString {
return ByteString(c.data)
}
func (c *fixedSize) WriteTo(w io.Writer) (n int64, err error) {
n32, err := w.Write(c.data)
return int64(n32), err
}
func (c *fixedSize) Read(p []byte) (n int, err error) {
return copy(p, c.data), nil
}
func (c *fixedSize) FoldToUint64() uint64 {
return FoldToUint64(c.data)
}
func (c *fixedSize) FixedByteSize() int {
return len(c.data)
}
func (c *fixedSize) AsBytes() []byte {
return c.data
}
func ReadFixedSize(v FoldableReader) []byte {
data := make([]byte, v.FixedByteSize())
n, err := v.Read(data)
if err != nil {
panic(err)
}
if n != len(data) {
panic("unexpected")
}
return data
}
func NewFixedReader(data []byte) FixedReader {
return &fixedSize{data: data}
}
func NewMutableFixedSize(data []byte) FixedReader {
return &fixedSize{data}
}
func CopyToMutable(v FoldableReader) FoldableReader {
return &fixedSize{ReadFixedSize(v)}
}
func NewImmutableFixedSize(data []byte) FixedReader {
return NewByteString(data).AsReader()
}
func CopyToImmutable(v FoldableReader) FoldableReader {
return NewByteString(ReadFixedSize(v)).AsReader()
}
func CopyFixedSize(v FoldableReader) FoldableReader {
r := fixedSize{}
r.data = make([]byte, v.FixedByteSize())
n, err := v.Read(r.data)
if err != nil {
panic(err)
}
if n != len(r.data) {
panic("unexpected")
}
return &r
}