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decode.go
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decode.go
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// Copyright (c) Faye Amacker. All rights reserved.
// Licensed under the MIT License. See LICENSE in the project root for license information.
package cbor
import (
"encoding"
"encoding/base64"
"encoding/binary"
"encoding/hex"
"errors"
"fmt"
"io"
"math"
"math/big"
"reflect"
"strconv"
"strings"
"time"
"unicode/utf8"
"github.com/x448/float16"
)
// Unmarshal parses the CBOR-encoded data into the value pointed to by v
// using default decoding options. If v is nil, not a pointer, or
// a nil pointer, Unmarshal returns an error.
//
// To unmarshal CBOR into a value implementing the Unmarshaler interface,
// Unmarshal calls that value's UnmarshalCBOR method with a valid
// CBOR value.
//
// To unmarshal CBOR byte string into a value implementing the
// encoding.BinaryUnmarshaler interface, Unmarshal calls that value's
// UnmarshalBinary method with decoded CBOR byte string.
//
// To unmarshal CBOR into a pointer, Unmarshal sets the pointer to nil
// if CBOR data is null (0xf6) or undefined (0xf7). Otherwise, Unmarshal
// unmarshals CBOR into the value pointed to by the pointer. If the
// pointer is nil, Unmarshal creates a new value for it to point to.
//
// To unmarshal CBOR into an empty interface value, Unmarshal uses the
// following rules:
//
// CBOR booleans decode to bool.
// CBOR positive integers decode to uint64.
// CBOR negative integers decode to int64 (big.Int if value overflows).
// CBOR floating points decode to float64.
// CBOR byte strings decode to []byte.
// CBOR text strings decode to string.
// CBOR arrays decode to []interface{}.
// CBOR maps decode to map[interface{}]interface{}.
// CBOR null and undefined values decode to nil.
// CBOR times (tag 0 and 1) decode to time.Time.
// CBOR bignums (tag 2 and 3) decode to big.Int.
// CBOR tags with an unrecognized number decode to cbor.Tag
//
// To unmarshal a CBOR array into a slice, Unmarshal allocates a new slice
// if the CBOR array is empty or slice capacity is less than CBOR array length.
// Otherwise Unmarshal overwrites existing elements, and sets slice length
// to CBOR array length.
//
// To unmarshal a CBOR array into a Go array, Unmarshal decodes CBOR array
// elements into Go array elements. If the Go array is smaller than the
// CBOR array, the extra CBOR array elements are discarded. If the CBOR
// array is smaller than the Go array, the extra Go array elements are
// set to zero values.
//
// To unmarshal a CBOR array into a struct, struct must have a special field "_"
// with struct tag `cbor:",toarray"`. Go array elements are decoded into struct
// fields. Any "omitempty" struct field tag option is ignored in this case.
//
// To unmarshal a CBOR map into a map, Unmarshal allocates a new map only if the
// map is nil. Otherwise Unmarshal reuses the existing map and keeps existing
// entries. Unmarshal stores key-value pairs from the CBOR map into Go map.
// See DecOptions.DupMapKey to enable duplicate map key detection.
//
// To unmarshal a CBOR map into a struct, Unmarshal matches CBOR map keys to the
// keys in the following priority:
//
// 1. "cbor" key in struct field tag,
// 2. "json" key in struct field tag,
// 3. struct field name.
//
// Unmarshal tries an exact match for field name, then a case-insensitive match.
// Map key-value pairs without corresponding struct fields are ignored. See
// DecOptions.ExtraReturnErrors to return error at unknown field.
//
// To unmarshal a CBOR text string into a time.Time value, Unmarshal parses text
// string formatted in RFC3339. To unmarshal a CBOR integer/float into a
// time.Time value, Unmarshal creates an unix time with integer/float as seconds
// and fractional seconds since January 1, 1970 UTC. As a special case, Infinite
// and NaN float values decode to time.Time's zero value.
//
// To unmarshal CBOR null (0xf6) and undefined (0xf7) values into a
// slice/map/pointer, Unmarshal sets Go value to nil. Because null is often
// used to mean "not present", unmarshalling CBOR null and undefined value
// into any other Go type has no effect and returns no error.
//
// Unmarshal supports CBOR tag 55799 (self-describe CBOR), tag 0 and 1 (time),
// and tag 2 and 3 (bignum).
//
// Unmarshal returns ExtraneousDataError error (without decoding into v)
// if there are any remaining bytes following the first valid CBOR data item.
// See UnmarshalFirst, if you want to unmarshal only the first
// CBOR data item without ExtraneousDataError caused by remaining bytes.
func Unmarshal(data []byte, v interface{}) error {
return defaultDecMode.Unmarshal(data, v)
}
// UnmarshalFirst parses the first CBOR data item into the value pointed to by v
// using default decoding options. Any remaining bytes are returned in rest.
//
// If v is nil, not a pointer, or a nil pointer, UnmarshalFirst returns an error.
//
// See the documentation for Unmarshal for details.
func UnmarshalFirst(data []byte, v interface{}) (rest []byte, err error) {
return defaultDecMode.UnmarshalFirst(data, v)
}
// Valid checks whether data is a well-formed encoded CBOR data item and
// that it complies with default restrictions such as MaxNestedLevels,
// MaxArrayElements, MaxMapPairs, etc.
//
// If there are any remaining bytes after the CBOR data item,
// an ExtraneousDataError is returned.
//
// WARNING: Valid doesn't check if encoded CBOR data item is valid (i.e. validity)
// and RFC 8949 distinctly defines what is "Valid" and what is "Well-formed".
//
// Deprecated: Valid is kept for compatibility and should not be used.
// Use Wellformed instead because it has a more appropriate name.
func Valid(data []byte) error {
return defaultDecMode.Valid(data)
}
// Wellformed checks whether data is a well-formed encoded CBOR data item and
// that it complies with default restrictions such as MaxNestedLevels,
// MaxArrayElements, MaxMapPairs, etc.
//
// If there are any remaining bytes after the CBOR data item,
// an ExtraneousDataError is returned.
func Wellformed(data []byte) error {
return defaultDecMode.Wellformed(data)
}
// Unmarshaler is the interface implemented by types that wish to unmarshal
// CBOR data themselves. The input is a valid CBOR value. UnmarshalCBOR
// must copy the CBOR data if it needs to use it after returning.
type Unmarshaler interface {
UnmarshalCBOR([]byte) error
}
// InvalidUnmarshalError describes an invalid argument passed to Unmarshal.
type InvalidUnmarshalError struct {
s string
}
func (e *InvalidUnmarshalError) Error() string {
return e.s
}
// UnmarshalTypeError describes a CBOR value that can't be decoded to a Go type.
type UnmarshalTypeError struct {
CBORType string // type of CBOR value
GoType string // type of Go value it could not be decoded into
StructFieldName string // name of the struct field holding the Go value (optional)
errorMsg string // additional error message (optional)
}
func (e *UnmarshalTypeError) Error() string {
var s string
if e.StructFieldName != "" {
s = "cbor: cannot unmarshal " + e.CBORType + " into Go struct field " + e.StructFieldName + " of type " + e.GoType
} else {
s = "cbor: cannot unmarshal " + e.CBORType + " into Go value of type " + e.GoType
}
if e.errorMsg != "" {
s += " (" + e.errorMsg + ")"
}
return s
}
// InvalidMapKeyTypeError describes invalid Go map key type when decoding CBOR map.
// For example, Go doesn't allow slice as map key.
type InvalidMapKeyTypeError struct {
GoType string
}
func (e *InvalidMapKeyTypeError) Error() string {
return "cbor: invalid map key type: " + e.GoType
}
// DupMapKeyError describes detected duplicate map key in CBOR map.
type DupMapKeyError struct {
Key interface{}
Index int
}
func (e *DupMapKeyError) Error() string {
return fmt.Sprintf("cbor: found duplicate map key \"%v\" at map element index %d", e.Key, e.Index)
}
// UnknownFieldError describes detected unknown field in CBOR map when decoding to Go struct.
type UnknownFieldError struct {
Index int
}
func (e *UnknownFieldError) Error() string {
return fmt.Sprintf("cbor: found unknown field at map element index %d", e.Index)
}
// UnacceptableDataItemError is returned when unmarshaling a CBOR input that contains a data item
// that is not acceptable to a specific CBOR-based application protocol ("invalid or unexpected" as
// described in RFC 8949 Section 5 Paragraph 3).
type UnacceptableDataItemError struct {
CBORType string
Message string
}
func (e UnacceptableDataItemError) Error() string {
return fmt.Sprintf("cbor: data item of cbor type %s is not accepted by protocol: %s", e.CBORType, e.Message)
}
// ByteStringExpectedFormatError is returned when unmarshaling CBOR byte string fails when
// using non-default ByteStringExpectedFormat decoding option that makes decoder expect
// a specified format such as base64, hex, etc.
type ByteStringExpectedFormatError struct {
expectedFormatOption ByteStringExpectedFormatMode
err error
}
func newByteStringExpectedFormatError(expectedFormatOption ByteStringExpectedFormatMode, err error) *ByteStringExpectedFormatError {
return &ByteStringExpectedFormatError{expectedFormatOption, err}
}
func (e *ByteStringExpectedFormatError) Error() string {
switch e.expectedFormatOption {
case ByteStringExpectedBase64URL:
return fmt.Sprintf("cbor: failed to decode base64url from byte string: %s", e.err)
case ByteStringExpectedBase64:
return fmt.Sprintf("cbor: failed to decode base64 from byte string: %s", e.err)
case ByteStringExpectedBase16:
return fmt.Sprintf("cbor: failed to decode hex from byte string: %s", e.err)
default:
return fmt.Sprintf("cbor: failed to decode byte string in expected format %d: %s", e.expectedFormatOption, e.err)
}
}
func (e *ByteStringExpectedFormatError) Unwrap() error {
return e.err
}
// InadmissibleTagContentTypeError is returned when unmarshaling built-in CBOR tags
// fails because of inadmissible type for tag content. Currently, the built-in
// CBOR tags in this codec are tags 0-3 and 21-23.
// See "Tag validity" in RFC 8949 Section 5.3.2.
type InadmissibleTagContentTypeError struct {
s string
tagNum int
expectedTagContentType string
gotTagContentType string
}
func newInadmissibleTagContentTypeError(
tagNum int,
expectedTagContentType string,
gotTagContentType string,
) *InadmissibleTagContentTypeError {
return &InadmissibleTagContentTypeError{
tagNum: tagNum,
expectedTagContentType: expectedTagContentType,
gotTagContentType: gotTagContentType,
}
}
func newInadmissibleTagContentTypeErrorf(s string) *InadmissibleTagContentTypeError {
return &InadmissibleTagContentTypeError{s: "cbor: " + s} //nolint:goconst // ignore "cbor"
}
func (e *InadmissibleTagContentTypeError) Error() string {
if e.s == "" {
return fmt.Sprintf(
"cbor: tag number %d must be followed by %s, got %s",
e.tagNum,
e.expectedTagContentType,
e.gotTagContentType,
)
}
return e.s
}
// DupMapKeyMode specifies how to enforce duplicate map key. Two map keys are considered duplicates if:
// 1. When decoding into a struct, both keys match the same struct field. The keys are also
// considered duplicates if neither matches any field and decoding to interface{} would produce
// equal (==) values for both keys.
// 2. When decoding into a map, both keys are equal (==) when decoded into values of the
// destination map's key type.
type DupMapKeyMode int
const (
// DupMapKeyQuiet doesn't enforce duplicate map key. Decoder quietly (no error)
// uses faster of "keep first" or "keep last" depending on Go data type and other factors.
DupMapKeyQuiet DupMapKeyMode = iota
// DupMapKeyEnforcedAPF enforces detection and rejection of duplicate map keys.
// APF means "Allow Partial Fill" and the destination map or struct can be partially filled.
// If a duplicate map key is detected, DupMapKeyError is returned without further decoding
// of the map. It's the caller's responsibility to respond to DupMapKeyError by
// discarding the partially filled result if their protocol requires it.
// WARNING: using DupMapKeyEnforcedAPF will decrease performance and increase memory use.
DupMapKeyEnforcedAPF
maxDupMapKeyMode
)
func (dmkm DupMapKeyMode) valid() bool {
return dmkm >= 0 && dmkm < maxDupMapKeyMode
}
// IndefLengthMode specifies whether to allow indefinite length items.
type IndefLengthMode int
const (
// IndefLengthAllowed allows indefinite length items.
IndefLengthAllowed IndefLengthMode = iota
// IndefLengthForbidden disallows indefinite length items.
IndefLengthForbidden
maxIndefLengthMode
)
func (m IndefLengthMode) valid() bool {
return m >= 0 && m < maxIndefLengthMode
}
// TagsMode specifies whether to allow CBOR tags.
type TagsMode int
const (
// TagsAllowed allows CBOR tags.
TagsAllowed TagsMode = iota
// TagsForbidden disallows CBOR tags.
TagsForbidden
maxTagsMode
)
func (tm TagsMode) valid() bool {
return tm >= 0 && tm < maxTagsMode
}
// IntDecMode specifies which Go type (int64, uint64, or big.Int) should
// be used when decoding CBOR integers (major type 0 and 1) to Go interface{}.
type IntDecMode int
const (
// IntDecConvertNone affects how CBOR integers (major type 0 and 1) decode to Go interface{}.
// It decodes CBOR unsigned integer (major type 0) to:
// - uint64
// It decodes CBOR negative integer (major type 1) to:
// - int64 if value fits
// - big.Int or *big.Int (see BigIntDecMode) if value doesn't fit into int64
IntDecConvertNone IntDecMode = iota
// IntDecConvertSigned affects how CBOR integers (major type 0 and 1) decode to Go interface{}.
// It decodes CBOR integers (major type 0 and 1) to:
// - int64 if value fits
// - big.Int or *big.Int (see BigIntDecMode) if value < math.MinInt64
// - return UnmarshalTypeError if value > math.MaxInt64
// Deprecated: IntDecConvertSigned should not be used.
// Please use other options, such as IntDecConvertSignedOrError, IntDecConvertSignedOrBigInt, IntDecConvertNone.
IntDecConvertSigned
// IntDecConvertSignedOrFail affects how CBOR integers (major type 0 and 1) decode to Go interface{}.
// It decodes CBOR integers (major type 0 and 1) to:
// - int64 if value fits
// - return UnmarshalTypeError if value doesn't fit into int64
IntDecConvertSignedOrFail
// IntDecConvertSigned affects how CBOR integers (major type 0 and 1) decode to Go interface{}.
// It makes CBOR integers (major type 0 and 1) decode to:
// - int64 if value fits
// - big.Int or *big.Int (see BigIntDecMode) if value doesn't fit into int64
IntDecConvertSignedOrBigInt
maxIntDec
)
func (idm IntDecMode) valid() bool {
return idm >= 0 && idm < maxIntDec
}
// MapKeyByteStringMode specifies how to decode CBOR byte string (major type 2)
// as Go map key when decoding CBOR map key into an empty Go interface value.
// Specifically, this option applies when decoding CBOR map into
// - Go empty interface, or
// - Go map with empty interface as key type.
// The CBOR map key types handled by this option are
// - byte string
// - tagged byte string
// - nested tagged byte string
type MapKeyByteStringMode int
const (
// MapKeyByteStringAllowed allows CBOR byte string to be decoded as Go map key.
// Since Go doesn't allow []byte as map key, CBOR byte string is decoded to
// ByteString which has underlying string type.
// This is the default setting.
MapKeyByteStringAllowed MapKeyByteStringMode = iota
// MapKeyByteStringForbidden forbids CBOR byte string being decoded as Go map key.
// Attempting to decode CBOR byte string as map key into empty interface value
// returns a decoding error.
MapKeyByteStringForbidden
maxMapKeyByteStringMode
)
func (mkbsm MapKeyByteStringMode) valid() bool {
return mkbsm >= 0 && mkbsm < maxMapKeyByteStringMode
}
// ExtraDecErrorCond specifies extra conditions that should be treated as errors.
type ExtraDecErrorCond uint
// ExtraDecErrorNone indicates no extra error condition.
const ExtraDecErrorNone ExtraDecErrorCond = 0
const (
// ExtraDecErrorUnknownField indicates error condition when destination
// Go struct doesn't have a field matching a CBOR map key.
ExtraDecErrorUnknownField ExtraDecErrorCond = 1 << iota
maxExtraDecError
)
func (ec ExtraDecErrorCond) valid() bool {
return ec < maxExtraDecError
}
// UTF8Mode option specifies if decoder should
// decode CBOR Text containing invalid UTF-8 string.
type UTF8Mode int
const (
// UTF8RejectInvalid rejects CBOR Text containing
// invalid UTF-8 string.
UTF8RejectInvalid UTF8Mode = iota
// UTF8DecodeInvalid allows decoding CBOR Text containing
// invalid UTF-8 string.
UTF8DecodeInvalid
maxUTF8Mode
)
func (um UTF8Mode) valid() bool {
return um >= 0 && um < maxUTF8Mode
}
// FieldNameMatchingMode specifies how string keys in CBOR maps are matched to Go struct field names.
type FieldNameMatchingMode int
const (
// FieldNameMatchingPreferCaseSensitive prefers to decode map items into struct fields whose names (or tag
// names) exactly match the item's key. If there is no such field, a map item will be decoded into a field whose
// name is a case-insensitive match for the item's key.
FieldNameMatchingPreferCaseSensitive FieldNameMatchingMode = iota
// FieldNameMatchingCaseSensitive decodes map items only into a struct field whose name (or tag name) is an
// exact match for the item's key.
FieldNameMatchingCaseSensitive
maxFieldNameMatchingMode
)
func (fnmm FieldNameMatchingMode) valid() bool {
return fnmm >= 0 && fnmm < maxFieldNameMatchingMode
}
// BigIntDecMode specifies how to decode CBOR bignum to Go interface{}.
type BigIntDecMode int
const (
// BigIntDecodeValue makes CBOR bignum decode to big.Int (instead of *big.Int)
// when unmarshalling into a Go interface{}.
BigIntDecodeValue BigIntDecMode = iota
// BigIntDecodePointer makes CBOR bignum decode to *big.Int when
// unmarshalling into a Go interface{}.
BigIntDecodePointer
maxBigIntDecMode
)
func (bidm BigIntDecMode) valid() bool {
return bidm >= 0 && bidm < maxBigIntDecMode
}
// ByteStringToStringMode specifies the behavior when decoding a CBOR byte string into a Go string.
type ByteStringToStringMode int
const (
// ByteStringToStringForbidden generates an error on an attempt to decode a CBOR byte string into a Go string.
ByteStringToStringForbidden ByteStringToStringMode = iota
// ByteStringToStringAllowed permits decoding a CBOR byte string into a Go string.
ByteStringToStringAllowed
// ByteStringToStringAllowedWithExpectedLaterEncoding permits decoding a CBOR byte string
// into a Go string. Also, if the byte string is enclosed (directly or indirectly) by one of
// the "expected later encoding" tags (numbers 21 through 23), the destination string will
// be populated by applying the designated text encoding to the contents of the input byte
// string.
ByteStringToStringAllowedWithExpectedLaterEncoding
maxByteStringToStringMode
)
func (bstsm ByteStringToStringMode) valid() bool {
return bstsm >= 0 && bstsm < maxByteStringToStringMode
}
// FieldNameByteStringMode specifies the behavior when decoding a CBOR byte string map key as a Go struct field name.
type FieldNameByteStringMode int
const (
// FieldNameByteStringForbidden generates an error on an attempt to decode a CBOR byte string map key as a Go struct field name.
FieldNameByteStringForbidden FieldNameByteStringMode = iota
// FieldNameByteStringAllowed permits CBOR byte string map keys to be recognized as Go struct field names.
FieldNameByteStringAllowed
maxFieldNameByteStringMode
)
func (fnbsm FieldNameByteStringMode) valid() bool {
return fnbsm >= 0 && fnbsm < maxFieldNameByteStringMode
}
// UnrecognizedTagToAnyMode specifies how to decode unrecognized CBOR tag into an empty interface (any).
// Currently, recognized CBOR tag numbers are 0, 1, 2, 3, or registered by TagSet.
type UnrecognizedTagToAnyMode int
const (
// UnrecognizedTagNumAndContentToAny decodes CBOR tag number and tag content to cbor.Tag
// when decoding unrecognized CBOR tag into an empty interface.
UnrecognizedTagNumAndContentToAny UnrecognizedTagToAnyMode = iota
// UnrecognizedTagContentToAny decodes only CBOR tag content (into its default type)
// when decoding unrecognized CBOR tag into an empty interface.
UnrecognizedTagContentToAny
maxUnrecognizedTagToAny
)
func (uttam UnrecognizedTagToAnyMode) valid() bool {
return uttam >= 0 && uttam < maxUnrecognizedTagToAny
}
// TimeTagToAnyMode specifies how to decode CBOR tag 0 and 1 into an empty interface (any).
// Based on the specified mode, Unmarshal can return a time.Time value or a time string in a specific format.
type TimeTagToAnyMode int
const (
// TimeTagToTime decodes CBOR tag 0 and 1 into a time.Time value
// when decoding tag 0 or 1 into an empty interface.
TimeTagToTime TimeTagToAnyMode = iota
// TimeTagToRFC3339 decodes CBOR tag 0 and 1 into a time string in RFC3339 format
// when decoding tag 0 or 1 into an empty interface.
TimeTagToRFC3339
// TimeTagToRFC3339Nano decodes CBOR tag 0 and 1 into a time string in RFC3339Nano format
// when decoding tag 0 or 1 into an empty interface.
TimeTagToRFC3339Nano
maxTimeTagToAnyMode
)
func (tttam TimeTagToAnyMode) valid() bool {
return tttam >= 0 && tttam < maxTimeTagToAnyMode
}
// SimpleValueRegistry is a registry of unmarshaling behaviors for each possible CBOR simple value
// number (0...23 and 32...255).
type SimpleValueRegistry struct {
rejected [256]bool
}
// WithRejectedSimpleValue registers the given simple value as rejected. If the simple value is
// encountered in a CBOR input during unmarshaling, an UnacceptableDataItemError is returned.
func WithRejectedSimpleValue(sv SimpleValue) func(*SimpleValueRegistry) error {
return func(r *SimpleValueRegistry) error {
if sv >= 24 && sv <= 31 {
return fmt.Errorf("cbor: cannot set analog for reserved simple value %d", sv)
}
r.rejected[sv] = true
return nil
}
}
// Creates a new SimpleValueRegistry. The registry state is initialized by executing the provided
// functions in order against a registry that is pre-populated with the defaults for all well-formed
// simple value numbers.
func NewSimpleValueRegistryFromDefaults(fns ...func(*SimpleValueRegistry) error) (*SimpleValueRegistry, error) {
var r SimpleValueRegistry
for _, fn := range fns {
if err := fn(&r); err != nil {
return nil, err
}
}
return &r, nil
}
// NaNMode specifies how to decode floating-point values (major type 7, additional information 25
// through 27) representing NaN (not-a-number).
type NaNMode int
const (
// NaNDecodeAllowed will decode NaN values to Go float32 or float64.
NaNDecodeAllowed NaNMode = iota
// NaNDecodeForbidden will return an UnacceptableDataItemError on an attempt to decode a NaN value.
NaNDecodeForbidden
maxNaNDecode
)
func (ndm NaNMode) valid() bool {
return ndm >= 0 && ndm < maxNaNDecode
}
// InfMode specifies how to decode floating-point values (major type 7, additional information 25
// through 27) representing positive or negative infinity.
type InfMode int
const (
// InfDecodeAllowed will decode infinite values to Go float32 or float64.
InfDecodeAllowed InfMode = iota
// InfDecodeForbidden will return an UnacceptableDataItemError on an attempt to decode an
// infinite value.
InfDecodeForbidden
maxInfDecode
)
func (idm InfMode) valid() bool {
return idm >= 0 && idm < maxInfDecode
}
// ByteStringToTimeMode specifies the behavior when decoding a CBOR byte string into a Go time.Time.
type ByteStringToTimeMode int
const (
// ByteStringToTimeForbidden generates an error on an attempt to decode a CBOR byte string into a Go time.Time.
ByteStringToTimeForbidden ByteStringToTimeMode = iota
// ByteStringToTimeAllowed permits decoding a CBOR byte string into a Go time.Time.
ByteStringToTimeAllowed
maxByteStringToTimeMode
)
func (bttm ByteStringToTimeMode) valid() bool {
return bttm >= 0 && bttm < maxByteStringToTimeMode
}
// ByteStringExpectedFormatMode specifies how to decode CBOR byte string into Go byte slice
// when the byte string is NOT enclosed in CBOR tag 21, 22, or 23. An error is returned if
// the CBOR byte string does not contain the expected format (e.g. base64) specified.
// For tags 21-23, see "Expected Later Encoding for CBOR-to-JSON Converters"
// in RFC 8949 Section 3.4.5.2.
type ByteStringExpectedFormatMode int
const (
// ByteStringExpectedFormatNone copies the unmodified CBOR byte string into Go byte slice
// if the byte string is not tagged by CBOR tag 21-23.
ByteStringExpectedFormatNone ByteStringExpectedFormatMode = iota
// ByteStringExpectedBase64URL expects CBOR byte strings to contain base64url-encoded bytes
// if the byte string is not tagged by CBOR tag 21-23. The decoder will attempt to decode
// the base64url-encoded bytes into Go slice.
ByteStringExpectedBase64URL
// ByteStringExpectedBase64 expects CBOR byte strings to contain base64-encoded bytes
// if the byte string is not tagged by CBOR tag 21-23. The decoder will attempt to decode
// the base64-encoded bytes into Go slice.
ByteStringExpectedBase64
// ByteStringExpectedBase16 expects CBOR byte strings to contain base16-encoded bytes
// if the byte string is not tagged by CBOR tag 21-23. The decoder will attempt to decode
// the base16-encoded bytes into Go slice.
ByteStringExpectedBase16
maxByteStringExpectedFormatMode
)
func (bsefm ByteStringExpectedFormatMode) valid() bool {
return bsefm >= 0 && bsefm < maxByteStringExpectedFormatMode
}
// BignumTagMode specifies whether or not the "bignum" tags 2 and 3 (RFC 8949 Section 3.4.3) can be
// decoded.
type BignumTagMode int
const (
// BignumTagAllowed allows bignum tags to be decoded.
BignumTagAllowed BignumTagMode = iota
// BignumTagForbidden produces an UnacceptableDataItemError during Unmarshal if a bignum tag
// is encountered in the input.
BignumTagForbidden
maxBignumTag
)
func (btm BignumTagMode) valid() bool {
return btm >= 0 && btm < maxBignumTag
}
// BinaryUnmarshalerMode specifies how to decode into types that implement
// encoding.BinaryUnmarshaler.
type BinaryUnmarshalerMode int
const (
// BinaryUnmarshalerByteString will invoke UnmarshalBinary on the contents of a CBOR byte
// string when decoding into a value that implements BinaryUnmarshaler.
BinaryUnmarshalerByteString BinaryUnmarshalerMode = iota
// BinaryUnmarshalerNone does not recognize BinaryUnmarshaler implementations during decode.
BinaryUnmarshalerNone
maxBinaryUnmarshalerMode
)
func (bum BinaryUnmarshalerMode) valid() bool {
return bum >= 0 && bum < maxBinaryUnmarshalerMode
}
// DecOptions specifies decoding options.
type DecOptions struct {
// DupMapKey specifies whether to enforce duplicate map key.
DupMapKey DupMapKeyMode
// TimeTag specifies whether or not untagged data items, or tags other
// than tag 0 and tag 1, can be decoded to time.Time. If tag 0 or tag 1
// appears in an input, the type of its content is always validated as
// specified in RFC 8949. That behavior is not controlled by this
// option. The behavior of the supported modes are:
//
// DecTagIgnored (default): Untagged text strings and text strings
// enclosed in tags other than 0 and 1 are decoded as though enclosed
// in tag 0. Untagged unsigned integers, negative integers, and
// floating-point numbers (or those enclosed in tags other than 0 and
// 1) are decoded as though enclosed in tag 1. Decoding a tag other
// than 0 or 1 enclosing simple values null or undefined into a
// time.Time does not modify the destination value.
//
// DecTagOptional: Untagged text strings are decoded as though
// enclosed in tag 0. Untagged unsigned integers, negative integers,
// and floating-point numbers are decoded as though enclosed in tag
// 1. Tags other than 0 and 1 will produce an error on attempts to
// decode them into a time.Time.
//
// DecTagRequired: Only tags 0 and 1 can be decoded to time.Time. Any
// other input will produce an error.
TimeTag DecTagMode
// MaxNestedLevels specifies the max nested levels allowed for any combination of CBOR array, maps, and tags.
// Default is 32 levels and it can be set to [4, 65535]. Note that higher maximum levels of nesting can
// require larger amounts of stack to deserialize. Don't increase this higher than you require.
MaxNestedLevels int
// MaxArrayElements specifies the max number of elements for CBOR arrays.
// Default is 128*1024=131072 and it can be set to [16, 2147483647]
MaxArrayElements int
// MaxMapPairs specifies the max number of key-value pairs for CBOR maps.
// Default is 128*1024=131072 and it can be set to [16, 2147483647]
MaxMapPairs int
// IndefLength specifies whether to allow indefinite length CBOR items.
IndefLength IndefLengthMode
// TagsMd specifies whether to allow CBOR tags (major type 6).
TagsMd TagsMode
// IntDec specifies which Go integer type (int64 or uint64) to use
// when decoding CBOR int (major type 0 and 1) to Go interface{}.
IntDec IntDecMode
// MapKeyByteString specifies how to decode CBOR byte string as map key
// when decoding CBOR map with byte string key into an empty interface value.
// By default, an error is returned when attempting to decode CBOR byte string
// as map key because Go doesn't allow []byte as map key.
MapKeyByteString MapKeyByteStringMode
// ExtraReturnErrors specifies extra conditions that should be treated as errors.
ExtraReturnErrors ExtraDecErrorCond
// DefaultMapType specifies Go map type to create and decode to
// when unmarshalling CBOR into an empty interface value.
// By default, unmarshal uses map[interface{}]interface{}.
DefaultMapType reflect.Type
// UTF8 specifies if decoder should decode CBOR Text containing invalid UTF-8.
// By default, unmarshal rejects CBOR text containing invalid UTF-8.
UTF8 UTF8Mode
// FieldNameMatching specifies how string keys in CBOR maps are matched to Go struct field names.
FieldNameMatching FieldNameMatchingMode
// BigIntDec specifies how to decode CBOR bignum to Go interface{}.
BigIntDec BigIntDecMode
// DefaultByteStringType is the Go type that should be produced when decoding a CBOR byte
// string into an empty interface value. Types to which a []byte is convertible are valid
// for this option, except for array and pointer-to-array types. If nil, the default is
// []byte.
DefaultByteStringType reflect.Type
// ByteStringToString specifies the behavior when decoding a CBOR byte string into a Go string.
ByteStringToString ByteStringToStringMode
// FieldNameByteString specifies the behavior when decoding a CBOR byte string map key as a
// Go struct field name.
FieldNameByteString FieldNameByteStringMode
// UnrecognizedTagToAny specifies how to decode unrecognized CBOR tag into an empty interface.
// Currently, recognized CBOR tag numbers are 0, 1, 2, 3, or registered by TagSet.
UnrecognizedTagToAny UnrecognizedTagToAnyMode
// TimeTagToAny specifies how to decode CBOR tag 0 and 1 into an empty interface (any).
// Based on the specified mode, Unmarshal can return a time.Time value or a time string in a specific format.
TimeTagToAny TimeTagToAnyMode
// SimpleValues is an immutable mapping from each CBOR simple value to a corresponding
// unmarshal behavior. If nil, the simple values false, true, null, and undefined are mapped
// to the Go analog values false, true, nil, and nil, respectively, and all other simple
// values N (except the reserved simple values 24 through 31) are mapped to
// cbor.SimpleValue(N). In other words, all well-formed simple values can be decoded.
//
// Users may provide a custom SimpleValueRegistry constructed via
// NewSimpleValueRegistryFromDefaults.
SimpleValues *SimpleValueRegistry
// NaN specifies how to decode floating-point values (major type 7, additional information
// 25 through 27) representing NaN (not-a-number).
NaN NaNMode
// Inf specifies how to decode floating-point values (major type 7, additional information
// 25 through 27) representing positive or negative infinity.
Inf InfMode
// ByteStringToTime specifies how to decode CBOR byte string into Go time.Time.
ByteStringToTime ByteStringToTimeMode
// ByteStringExpectedFormat specifies how to decode CBOR byte string into Go byte slice
// when the byte string is NOT enclosed in CBOR tag 21, 22, or 23. An error is returned if
// the CBOR byte string does not contain the expected format (e.g. base64) specified.
// For tags 21-23, see "Expected Later Encoding for CBOR-to-JSON Converters"
// in RFC 8949 Section 3.4.5.2.
ByteStringExpectedFormat ByteStringExpectedFormatMode
// BignumTag specifies whether or not the "bignum" tags 2 and 3 (RFC 8949 Section 3.4.3) can
// be decoded. Unlike BigIntDec, this option applies to all bignum tags encountered in a
// CBOR input, independent of the type of the destination value of a particular Unmarshal
// operation.
BignumTag BignumTagMode
// BinaryUnmarshaler specifies how to decode into types that implement
// encoding.BinaryUnmarshaler.
BinaryUnmarshaler BinaryUnmarshalerMode
}
// DecMode returns DecMode with immutable options and no tags (safe for concurrency).
func (opts DecOptions) DecMode() (DecMode, error) { //nolint:gocritic // ignore hugeParam
return opts.decMode()
}
// validForTags checks that the provided tag set is compatible with these options and returns a
// non-nil error if and only if the provided tag set is incompatible.
func (opts DecOptions) validForTags(tags TagSet) error { //nolint:gocritic // ignore hugeParam
if opts.TagsMd == TagsForbidden {
return errors.New("cbor: cannot create DecMode with TagSet when TagsMd is TagsForbidden")
}
if tags == nil {
return errors.New("cbor: cannot create DecMode with nil value as TagSet")
}
if opts.ByteStringToString == ByteStringToStringAllowedWithExpectedLaterEncoding ||
opts.ByteStringExpectedFormat != ByteStringExpectedFormatNone {
for _, tagNum := range []uint64{
tagNumExpectedLaterEncodingBase64URL,
tagNumExpectedLaterEncodingBase64,
tagNumExpectedLaterEncodingBase16,
} {
if rt := tags.getTypeFromTagNum([]uint64{tagNum}); rt != nil {
return fmt.Errorf("cbor: DecMode with non-default StringExpectedEncoding or ByteSliceExpectedEncoding treats tag %d as built-in and conflicts with the provided TagSet's registration of %v", tagNum, rt)
}
}
}
return nil
}
// DecModeWithTags returns DecMode with options and tags that are both immutable (safe for concurrency).
func (opts DecOptions) DecModeWithTags(tags TagSet) (DecMode, error) { //nolint:gocritic // ignore hugeParam
if err := opts.validForTags(tags); err != nil {
return nil, err
}
dm, err := opts.decMode()
if err != nil {
return nil, err
}
// Copy tags
ts := tagSet(make(map[reflect.Type]*tagItem))
syncTags := tags.(*syncTagSet)
syncTags.RLock()
for contentType, tag := range syncTags.t {
if tag.opts.DecTag != DecTagIgnored {
ts[contentType] = tag
}
}
syncTags.RUnlock()
if len(ts) > 0 {
dm.tags = ts
}
return dm, nil
}
// DecModeWithSharedTags returns DecMode with immutable options and mutable shared tags (safe for concurrency).
func (opts DecOptions) DecModeWithSharedTags(tags TagSet) (DecMode, error) { //nolint:gocritic // ignore hugeParam
if err := opts.validForTags(tags); err != nil {
return nil, err
}
dm, err := opts.decMode()
if err != nil {
return nil, err
}
dm.tags = tags
return dm, nil
}
const (
defaultMaxArrayElements = 131072
minMaxArrayElements = 16
maxMaxArrayElements = 2147483647
defaultMaxMapPairs = 131072
minMaxMapPairs = 16
maxMaxMapPairs = 2147483647
defaultMaxNestedLevels = 32
minMaxNestedLevels = 4
maxMaxNestedLevels = 65535
)
var defaultSimpleValues = func() *SimpleValueRegistry {
registry, err := NewSimpleValueRegistryFromDefaults()
if err != nil {
panic(err)
}
return registry
}()
//nolint:gocyclo // Each option comes with some manageable boilerplate
func (opts DecOptions) decMode() (*decMode, error) { //nolint:gocritic // ignore hugeParam
if !opts.DupMapKey.valid() {
return nil, errors.New("cbor: invalid DupMapKey " + strconv.Itoa(int(opts.DupMapKey)))
}
if !opts.TimeTag.valid() {
return nil, errors.New("cbor: invalid TimeTag " + strconv.Itoa(int(opts.TimeTag)))
}
if !opts.IndefLength.valid() {
return nil, errors.New("cbor: invalid IndefLength " + strconv.Itoa(int(opts.IndefLength)))
}
if !opts.TagsMd.valid() {
return nil, errors.New("cbor: invalid TagsMd " + strconv.Itoa(int(opts.TagsMd)))
}
if !opts.IntDec.valid() {
return nil, errors.New("cbor: invalid IntDec " + strconv.Itoa(int(opts.IntDec)))
}
if !opts.MapKeyByteString.valid() {
return nil, errors.New("cbor: invalid MapKeyByteString " + strconv.Itoa(int(opts.MapKeyByteString)))