mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-11-15 02:40:23 +00:00
130 lines
4.3 KiB
Go
130 lines
4.3 KiB
Go
|
// Copyright (c) Faye Amacker. All rights reserved.
|
||
|
// Licensed under the MIT License. See LICENSE in the project root for license information.
|
||
|
|
||
|
/*
|
||
|
Package cbor is a modern CBOR codec (RFC 8949 & RFC 7049) with CBOR tags,
|
||
|
Go struct tags (toarray/keyasint/omitempty), Core Deterministic Encoding,
|
||
|
CTAP2, Canonical CBOR, float64->32->16, and duplicate map key detection.
|
||
|
|
||
|
Encoding options allow "preferred serialization" by encoding integers and floats
|
||
|
to their smallest forms (e.g. float16) when values fit.
|
||
|
|
||
|
Struct tags like "keyasint", "toarray" and "omitempty" make CBOR data smaller
|
||
|
and easier to use with structs.
|
||
|
|
||
|
For example, "toarray" tag makes struct fields encode to CBOR array elements. And
|
||
|
"keyasint" makes a field encode to an element of CBOR map with specified int key.
|
||
|
|
||
|
Latest docs can be viewed at https://github.com/fxamacker/cbor#cbor-library-in-go
|
||
|
|
||
|
# Basics
|
||
|
|
||
|
The Quick Start guide is at https://github.com/fxamacker/cbor#quick-start
|
||
|
|
||
|
Function signatures identical to encoding/json include:
|
||
|
|
||
|
Marshal, Unmarshal, NewEncoder, NewDecoder, (*Encoder).Encode, (*Decoder).Decode.
|
||
|
|
||
|
Standard interfaces include:
|
||
|
|
||
|
BinaryMarshaler, BinaryUnmarshaler, Marshaler, and Unmarshaler.
|
||
|
|
||
|
Custom encoding and decoding is possible by implementing standard interfaces for
|
||
|
user-defined Go types.
|
||
|
|
||
|
Codec functions are available at package-level (using defaults options) or by
|
||
|
creating modes from options at runtime.
|
||
|
|
||
|
"Mode" in this API means definite way of encoding (EncMode) or decoding (DecMode).
|
||
|
|
||
|
EncMode and DecMode interfaces are created from EncOptions or DecOptions structs.
|
||
|
|
||
|
em, err := cbor.EncOptions{...}.EncMode()
|
||
|
em, err := cbor.CanonicalEncOptions().EncMode()
|
||
|
em, err := cbor.CTAP2EncOptions().EncMode()
|
||
|
|
||
|
Modes use immutable options to avoid side-effects and simplify concurrency. Behavior of
|
||
|
modes won't accidentally change at runtime after they're created.
|
||
|
|
||
|
Modes are intended to be reused and are safe for concurrent use.
|
||
|
|
||
|
EncMode and DecMode Interfaces
|
||
|
|
||
|
// EncMode interface uses immutable options and is safe for concurrent use.
|
||
|
type EncMode interface {
|
||
|
Marshal(v interface{}) ([]byte, error)
|
||
|
NewEncoder(w io.Writer) *Encoder
|
||
|
EncOptions() EncOptions // returns copy of options
|
||
|
}
|
||
|
|
||
|
// DecMode interface uses immutable options and is safe for concurrent use.
|
||
|
type DecMode interface {
|
||
|
Unmarshal(data []byte, v interface{}) error
|
||
|
NewDecoder(r io.Reader) *Decoder
|
||
|
DecOptions() DecOptions // returns copy of options
|
||
|
}
|
||
|
|
||
|
Using Default Encoding Mode
|
||
|
|
||
|
b, err := cbor.Marshal(v)
|
||
|
|
||
|
encoder := cbor.NewEncoder(w)
|
||
|
err = encoder.Encode(v)
|
||
|
|
||
|
Using Default Decoding Mode
|
||
|
|
||
|
err := cbor.Unmarshal(b, &v)
|
||
|
|
||
|
decoder := cbor.NewDecoder(r)
|
||
|
err = decoder.Decode(&v)
|
||
|
|
||
|
Creating and Using Encoding Modes
|
||
|
|
||
|
// Create EncOptions using either struct literal or a function.
|
||
|
opts := cbor.CanonicalEncOptions()
|
||
|
|
||
|
// If needed, modify encoding options
|
||
|
opts.Time = cbor.TimeUnix
|
||
|
|
||
|
// Create reusable EncMode interface with immutable options, safe for concurrent use.
|
||
|
em, err := opts.EncMode()
|
||
|
|
||
|
// Use EncMode like encoding/json, with same function signatures.
|
||
|
b, err := em.Marshal(v)
|
||
|
// or
|
||
|
encoder := em.NewEncoder(w)
|
||
|
err := encoder.Encode(v)
|
||
|
|
||
|
// NOTE: Both em.Marshal(v) and encoder.Encode(v) use encoding options
|
||
|
// specified during creation of em (encoding mode).
|
||
|
|
||
|
# CBOR Options
|
||
|
|
||
|
Predefined Encoding Options: https://github.com/fxamacker/cbor#predefined-encoding-options
|
||
|
|
||
|
Encoding Options: https://github.com/fxamacker/cbor#encoding-options
|
||
|
|
||
|
Decoding Options: https://github.com/fxamacker/cbor#decoding-options
|
||
|
|
||
|
# Struct Tags
|
||
|
|
||
|
Struct tags like `cbor:"name,omitempty"` and `json:"name,omitempty"` work as expected.
|
||
|
If both struct tags are specified then `cbor` is used.
|
||
|
|
||
|
Struct tags like "keyasint", "toarray", and "omitempty" make it easy to use
|
||
|
very compact formats like COSE and CWT (CBOR Web Tokens) with structs.
|
||
|
|
||
|
For example, "toarray" makes struct fields encode to array elements. And "keyasint"
|
||
|
makes struct fields encode to elements of CBOR map with int keys.
|
||
|
|
||
|
https://raw.githubusercontent.com/fxamacker/images/master/cbor/v2.0.0/cbor_easy_api.png
|
||
|
|
||
|
Struct tags are listed at https://github.com/fxamacker/cbor#struct-tags-1
|
||
|
|
||
|
# Tests and Fuzzing
|
||
|
|
||
|
Over 375 tests are included in this package. Cover-guided fuzzing is handled by
|
||
|
a private fuzzer that replaced fxamacker/cbor-fuzz years ago.
|
||
|
*/
|
||
|
package cbor
|