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