110 lines
3.6 KiB
Go
110 lines
3.6 KiB
Go
// Copyright (c) Faye Amacker. All rights reserved.
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// Licensed under the MIT License. See LICENSE in the project root for license information.
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/*
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Package cbor is a fast & safe CBOR encoder & decoder (RFC 7049) with a
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standard API + toarray & keyasint struct tags, CBOR tags, float64->32->16,
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CTAP2 & Canonical CBOR, duplicate map key options, and is customizable via
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simple API.
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CBOR encoding options allow "preferred serialization" by encoding integers and floats
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to their smallest forms (like float16) when values fit.
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Struct tags like "keyasint", "toarray" and "omitempty" makes CBOR data smaller.
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For example, "toarray" makes struct fields encode to array elements. And "keyasint"
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makes struct fields encode to elements of CBOR map with int keys.
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Basics
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Function signatures identical to encoding/json include:
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Marshal, Unmarshal, NewEncoder, NewDecoder, encoder.Encode, decoder.Decode.
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Codec functions are available at package-level (using defaults) or by creating modes
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from options at runtime.
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"Mode" in this API means definite way of encoding or decoding. Specifically, EncMode or DecMode.
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EncMode and DecMode interfaces are created from EncOptions or DecOptions structs. For example,
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em := cbor.EncOptions{...}.EncMode()
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em := cbor.CanonicalEncOptions().EncMode()
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em := cbor.CTAP2EncOptions().EncMode()
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Modes use immutable options to avoid side-effects and simplify concurrency. Behavior of modes
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won't accidentally change at runtime after they're created.
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Modes are intended to be reused and are safe for concurrent use.
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EncMode and DecMode Interfaces
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// EncMode interface uses immutable options and is safe for concurrent use.
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type EncMode interface {
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Marshal(v interface{}) ([]byte, error)
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NewEncoder(w io.Writer) *Encoder
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EncOptions() EncOptions // returns copy of options
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}
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// DecMode interface uses immutable options and is safe for concurrent use.
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type DecMode interface {
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Unmarshal(data []byte, v interface{}) error
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NewDecoder(r io.Reader) *Decoder
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DecOptions() DecOptions // returns copy of options
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}
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Using Default Encoding Mode
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b, err := cbor.Marshal(v)
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encoder := cbor.NewEncoder(w)
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err = encoder.Encode(v)
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Using Default Decoding Mode
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err := cbor.Unmarshal(b, &v)
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decoder := cbor.NewDecoder(r)
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err = decoder.Decode(&v)
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Creating and Using Encoding Modes
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// Create EncOptions using either struct literal or a function.
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opts := cbor.CanonicalEncOptions()
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// If needed, modify encoding options
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opts.Time = cbor.TimeUnix
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// Create reusable EncMode interface with immutable options, safe for concurrent use.
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em, err := opts.EncMode()
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// Use EncMode like encoding/json, with same function signatures.
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b, err := em.Marshal(v)
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// or
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encoder := em.NewEncoder(w)
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err := encoder.Encode(v)
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Default Options
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Default encoding options are listed at https://github.com/fxamacker/cbor#api
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Struct Tags
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Struct tags like `cbor:"name,omitempty"` and `json:"name,omitempty"` work as expected.
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If both struct tags are specified then `cbor` is used.
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Struct tags like "keyasint", "toarray", and "omitempty" make it easy to use
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very compact formats like COSE and CWT (CBOR Web Tokens) with structs.
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For example, "toarray" makes struct fields encode to array elements. And "keyasint"
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makes struct fields encode to elements of CBOR map with int keys.
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https://raw.githubusercontent.com/fxamacker/images/master/cbor/v2.0.0/cbor_easy_api.png
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Tests and Fuzzing
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Over 375 tests are included in this package. Cover-guided fuzzing is handled by a separate package:
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fxamacker/cbor-fuzz.
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*/
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package cbor
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