+++ /dev/null
-/*
-Copyright 2012 Google Inc.
-
-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 groupcache
-
-import (
- "bytes"
- "errors"
- "io"
- "strings"
-)
-
-// A ByteView holds an immutable view of bytes.
-// Internally it wraps either a []byte or a string,
-// but that detail is invisible to callers.
-//
-// A ByteView is meant to be used as a value type, not
-// a pointer (like a time.Time).
-type ByteView struct {
- // If b is non-nil, b is used, else s is used.
- b []byte
- s string
-}
-
-// Len returns the view's length.
-func (v ByteView) Len() int {
- if v.b != nil {
- return len(v.b)
- }
- return len(v.s)
-}
-
-// ByteSlice returns a copy of the data as a byte slice.
-func (v ByteView) ByteSlice() []byte {
- if v.b != nil {
- return cloneBytes(v.b)
- }
- return []byte(v.s)
-}
-
-// String returns the data as a string, making a copy if necessary.
-func (v ByteView) String() string {
- if v.b != nil {
- return string(v.b)
- }
- return v.s
-}
-
-// At returns the byte at index i.
-func (v ByteView) At(i int) byte {
- if v.b != nil {
- return v.b[i]
- }
- return v.s[i]
-}
-
-// Slice slices the view between the provided from and to indices.
-func (v ByteView) Slice(from, to int) ByteView {
- if v.b != nil {
- return ByteView{b: v.b[from:to]}
- }
- return ByteView{s: v.s[from:to]}
-}
-
-// SliceFrom slices the view from the provided index until the end.
-func (v ByteView) SliceFrom(from int) ByteView {
- if v.b != nil {
- return ByteView{b: v.b[from:]}
- }
- return ByteView{s: v.s[from:]}
-}
-
-// Copy copies b into dest and returns the number of bytes copied.
-func (v ByteView) Copy(dest []byte) int {
- if v.b != nil {
- return copy(dest, v.b)
- }
- return copy(dest, v.s)
-}
-
-// Equal returns whether the bytes in b are the same as the bytes in
-// b2.
-func (v ByteView) Equal(b2 ByteView) bool {
- if b2.b == nil {
- return v.EqualString(b2.s)
- }
- return v.EqualBytes(b2.b)
-}
-
-// EqualString returns whether the bytes in b are the same as the bytes
-// in s.
-func (v ByteView) EqualString(s string) bool {
- if v.b == nil {
- return v.s == s
- }
- l := v.Len()
- if len(s) != l {
- return false
- }
- for i, bi := range v.b {
- if bi != s[i] {
- return false
- }
- }
- return true
-}
-
-// EqualBytes returns whether the bytes in b are the same as the bytes
-// in b2.
-func (v ByteView) EqualBytes(b2 []byte) bool {
- if v.b != nil {
- return bytes.Equal(v.b, b2)
- }
- l := v.Len()
- if len(b2) != l {
- return false
- }
- for i, bi := range b2 {
- if bi != v.s[i] {
- return false
- }
- }
- return true
-}
-
-// Reader returns an io.ReadSeeker for the bytes in v.
-func (v ByteView) Reader() io.ReadSeeker {
- if v.b != nil {
- return bytes.NewReader(v.b)
- }
- return strings.NewReader(v.s)
-}
-
-// ReadAt implements io.ReaderAt on the bytes in v.
-func (v ByteView) ReadAt(p []byte, off int64) (n int, err error) {
- if off < 0 {
- return 0, errors.New("view: invalid offset")
- }
- if off >= int64(v.Len()) {
- return 0, io.EOF
- }
- n = v.SliceFrom(int(off)).Copy(p)
- if n < len(p) {
- err = io.EOF
- }
- return
-}
-
-// WriteTo implements io.WriterTo on the bytes in v.
-func (v ByteView) WriteTo(w io.Writer) (n int64, err error) {
- var m int
- if v.b != nil {
- m, err = w.Write(v.b)
- } else {
- m, err = io.WriteString(w, v.s)
- }
- if err == nil && m < v.Len() {
- err = io.ErrShortWrite
- }
- n = int64(m)
- return
-}
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