cbor.go

Documentation: github.com/rs/zerolog/internal/cbor

     1  // Package cbor provides primitives for storing different data
     2  // in the CBOR (binary) format. CBOR is defined in RFC7049.
     3  package cbor
     4  
     5  import "time"
     6  
     7  const (
     8  	majorOffset   = 5
     9  	additionalMax = 23
    10  
    11  	// Non Values.
    12  	additionalTypeBoolFalse byte = 20
    13  	additionalTypeBoolTrue  byte = 21
    14  	additionalTypeNull      byte = 22
    15  
    16  	// Integer (+ve and -ve) Sub-types.
    17  	additionalTypeIntUint8  byte = 24
    18  	additionalTypeIntUint16 byte = 25
    19  	additionalTypeIntUint32 byte = 26
    20  	additionalTypeIntUint64 byte = 27
    21  
    22  	// Float Sub-types.
    23  	additionalTypeFloat16 byte = 25
    24  	additionalTypeFloat32 byte = 26
    25  	additionalTypeFloat64 byte = 27
    26  	additionalTypeBreak   byte = 31
    27  
    28  	// Tag Sub-types.
    29  	additionalTypeTimestamp byte = 01
    30  
    31  	// Extended Tags - from https://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml
    32  	additionalTypeTagNetworkAddr   uint16 = 260
    33  	additionalTypeTagNetworkPrefix uint16 = 261
    34  	additionalTypeEmbeddedJSON     uint16 = 262
    35  	additionalTypeTagHexString     uint16 = 263
    36  
    37  	// Unspecified number of elements.
    38  	additionalTypeInfiniteCount byte = 31
    39  )
    40  const (
    41  	majorTypeUnsignedInt    byte = iota << majorOffset // Major type 0
    42  	majorTypeNegativeInt                               // Major type 1
    43  	majorTypeByteString                                // Major type 2
    44  	majorTypeUtf8String                                // Major type 3
    45  	majorTypeArray                                     // Major type 4
    46  	majorTypeMap                                       // Major type 5
    47  	majorTypeTags                                      // Major type 6
    48  	majorTypeSimpleAndFloat                            // Major type 7
    49  )
    50  
    51  const (
    52  	maskOutAdditionalType byte = (7 << majorOffset)
    53  	maskOutMajorType      byte = 31
    54  )
    55  
    56  const (
    57  	float32Nan         = "\xfa\x7f\xc0\x00\x00"
    58  	float32PosInfinity = "\xfa\x7f\x80\x00\x00"
    59  	float32NegInfinity = "\xfa\xff\x80\x00\x00"
    60  	float64Nan         = "\xfb\x7f\xf8\x00\x00\x00\x00\x00\x00"
    61  	float64PosInfinity = "\xfb\x7f\xf0\x00\x00\x00\x00\x00\x00"
    62  	float64NegInfinity = "\xfb\xff\xf0\x00\x00\x00\x00\x00\x00"
    63  )
    64  
    65  // IntegerTimeFieldFormat indicates the format of timestamp decoded
    66  // from an integer (time in seconds).
    67  var IntegerTimeFieldFormat = time.RFC3339
    68  
    69  // NanoTimeFieldFormat indicates the format of timestamp decoded
    70  // from a float value (time in seconds and nanoseconds).
    71  var NanoTimeFieldFormat = time.RFC3339Nano
    72  
    73  func appendCborTypePrefix(dst []byte, major byte, number uint64) []byte {
    74  	byteCount := 8
    75  	var minor byte
    76  	switch {
    77  	case number < 256:
    78  		byteCount = 1
    79  		minor = additionalTypeIntUint8
    80  
    81  	case number < 65536:
    82  		byteCount = 2
    83  		minor = additionalTypeIntUint16
    84  
    85  	case number < 4294967296:
    86  		byteCount = 4
    87  		minor = additionalTypeIntUint32
    88  
    89  	default:
    90  		byteCount = 8
    91  		minor = additionalTypeIntUint64
    92  
    93  	}
    94  
    95  	dst = append(dst, major|minor)
    96  	byteCount--
    97  	for ; byteCount >= 0; byteCount-- {
    98  		dst = append(dst, byte(number>>(uint(byteCount)*8)))
    99  	}
   100  	return dst
   101  }
   102
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