zlog/internal/cbor/cbor.go

101 lines
2.8 KiB
Go

// Package cbor provides primitives for storing different data
// in the CBOR (binary) format. CBOR is defined in RFC7049.
package cbor
import "time"
const (
majorOffset = 5
additionalMax = 23
// Non Values.
additionalTypeBoolFalse byte = 20
additionalTypeBoolTrue byte = 21
additionalTypeNull byte = 22
// Integer (+ve and -ve) Sub-types.
additionalTypeIntUint8 byte = 24
additionalTypeIntUint16 byte = 25
additionalTypeIntUint32 byte = 26
additionalTypeIntUint64 byte = 27
// Float Sub-types.
additionalTypeFloat16 byte = 25
additionalTypeFloat32 byte = 26
additionalTypeFloat64 byte = 27
additionalTypeBreak byte = 31
// Tag Sub-types.
additionalTypeTimestamp byte = 01
// Extended Tags - from https://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml
additionalTypeTagNetworkAddr uint16 = 260
additionalTypeTagNetworkPrefix uint16 = 261
additionalTypeEmbeddedJSON uint16 = 262
additionalTypeTagHexString uint16 = 263
// Unspecified number of elements.
additionalTypeInfiniteCount byte = 31
)
const (
majorTypeUnsignedInt byte = iota << majorOffset // Major type 0
majorTypeNegativeInt // Major type 1
majorTypeByteString // Major type 2
majorTypeUtf8String // Major type 3
majorTypeArray // Major type 4
majorTypeMap // Major type 5
majorTypeTags // Major type 6
majorTypeSimpleAndFloat // Major type 7
)
const (
maskOutAdditionalType byte = (7 << majorOffset)
maskOutMajorType byte = 31
)
const (
float32Nan = "\xfa\x7f\xc0\x00\x00"
float32PosInfinity = "\xfa\x7f\x80\x00\x00"
float32NegInfinity = "\xfa\xff\x80\x00\x00"
float64Nan = "\xfb\x7f\xf8\x00\x00\x00\x00\x00\x00"
float64PosInfinity = "\xfb\x7f\xf0\x00\x00\x00\x00\x00\x00"
float64NegInfinity = "\xfb\xff\xf0\x00\x00\x00\x00\x00\x00"
)
// IntegerTimeFieldFormat indicates the format of timestamp decoded
// from an integer (time in seconds).
var IntegerTimeFieldFormat = time.RFC3339
// NanoTimeFieldFormat indicates the format of timestamp decoded
// from a float value (time in seconds and nano seconds).
var NanoTimeFieldFormat = time.RFC3339Nano
func appendCborTypePrefix(dst []byte, major byte, number uint64) []byte {
byteCount := 8
var minor byte
switch {
case number < 256:
byteCount = 1
minor = additionalTypeIntUint8
case number < 65536:
byteCount = 2
minor = additionalTypeIntUint16
case number < 4294967296:
byteCount = 4
minor = additionalTypeIntUint32
default:
byteCount = 8
minor = additionalTypeIntUint64
}
dst = append(dst, byte(major|minor))
byteCount--
for ; byteCount >= 0; byteCount-- {
dst = append(dst, byte(number>>(uint(byteCount)*8)))
}
return dst
}