wire

Documentation

Overview

Package wire parses and formats the protobuf wire encoding.

See https://developers.google.com/protocol-buffers/docs/encoding.

Index

• func AppendBytes(b []byte, v []byte) []byte
• func AppendFixed32(b []byte, v uint32) []byte
• func AppendFixed64(b []byte, v uint64) []byte
• func AppendGroup(b []byte, num Number, v []byte) []byte
• func AppendTag(b []byte, num Number, typ Type) []byte
• func AppendVarint(b []byte, v uint64) []byte
• func ConsumeBytes(b []byte) (v []byte, n int)
• func ConsumeField(visitor Visitor, b []byte) (Number, Type, int)
• func ConsumeFieldValue(visitor Visitor, num Number, typ Type, b []byte) (n int)
• func ConsumeFixed32(b []byte) (v uint32, n int)
• func ConsumeFixed64(b []byte) (v uint64, n int)
• func ConsumeGroup(visitor Visitor, num Number, b []byte) (v []byte, n int)
• func ConsumeTag(b []byte) (Number, Type, int)
• func ConsumeVarint(b []byte) (v uint64, n int)
• func DecodeBool(x uint64) bool
• func DecodeTag(x uint64) (Number, Type)
• func DecodeZigZag(x uint64) int64
• func EncodeBool(x bool) uint64
• func EncodeTag(num Number, typ Type) uint64
• func EncodeZigZag(x int64) uint64
• func ParseError(n int) error
• func SizeBytes(n int) int
• func SizeFixed32() int
• func SizeFixed64() int
• func SizeGroup(num Number, n int) int
• func SizeTag(num Number) int
• func SizeVarint(v uint64) int
• type Number
• type Type
• type Visitor

Functions

func AppendBytes

func AppendBytes(b []byte, v []byte) []byte

AppendBytes appends v to b as a length-prefixed bytes value.

func AppendFixed32

func AppendFixed32(b []byte, v uint32) []byte

AppendFixed32 appends v to b as a little-endian uint32.

func AppendFixed64

func AppendFixed64(b []byte, v uint64) []byte

AppendFixed64 appends v to b as a little-endian uint64.

func AppendGroup

func AppendGroup(b []byte, num Number, v []byte) []byte

AppendGroup appends v to b as group value, with a trailing end group marker. The value v must not contain the end marker.

func AppendTag

func AppendTag(b []byte, num Number, typ Type) []byte

AppendTag encodes num and typ as a varint-encoded tag and appends it to b.

func AppendVarint

func AppendVarint(b []byte, v uint64) []byte

AppendVarint appends v to b as a varint-encoded uint64.

func ConsumeBytes

func ConsumeBytes(b []byte) (v []byte, n int)

ConsumeBytes parses b as a length-prefixed bytes value, reporting its length. This returns a negative length upon an error (see ParseError).

func ConsumeField

func ConsumeField(visitor Visitor, b []byte) (Number, Type, int)

ConsumeField parses an entire field record (both tag and value) and returns the field number, the wire type, and the total length. This returns a negative length upon an error (see ParseError).

The total length includes the tag header and the end group marker (if the field is a group).

func ConsumeFieldValue

func ConsumeFieldValue(visitor Visitor, num Number, typ Type, b []byte) (n int)

ConsumeFieldValue parses a field value and returns its length. This assumes that the field Number and wire Type have already been parsed. This returns a negative length upon an error (see ParseError).

When parsing a group, the length includes the end group marker and the end group is verified to match the starting field number.

func ConsumeFixed32

func ConsumeFixed32(b []byte) (v uint32, n int)

ConsumeFixed32 parses b as a little-endian uint32, reporting its length. This returns a negative length upon an error (see ParseError).

func ConsumeFixed64

func ConsumeFixed64(b []byte) (v uint64, n int)

ConsumeFixed64 parses b as a little-endian uint64, reporting its length. This returns a negative length upon an error (see ParseError).

func ConsumeGroup

func ConsumeGroup(visitor Visitor, num Number, b []byte) (v []byte, n int)

ConsumeGroup parses b as a group value until the trailing end group marker, and verifies that the end marker matches the provided num. The value v does not contain the end marker, while the length does contain the end marker. This returns a negative length upon an error (see ParseError).

func ConsumeTag

func ConsumeTag(b []byte) (Number, Type, int)

ConsumeTag parses b as a varint-encoded tag, reporting its length. This returns a negative length upon an error (see ParseError).

func ConsumeVarint

func ConsumeVarint(b []byte) (v uint64, n int)

ConsumeVarint parses b as a varint-encoded uint64, reporting its length. This returns a negative length upon an error (see ParseError).

func DecodeBool

func DecodeBool(x uint64) bool

DecodeBool decodes a uint64 as a bool.

Input:  {    0,    1,    2, …}
Output: {false, true, true, …}

func DecodeTag

func DecodeTag(x uint64) (Number, Type)

DecodeTag decodes the field Number and wire Type from its unified form. The Number is -1 if the decoded field number overflows. Other than overflow, this does not check for field number validity.

func DecodeZigZag

func DecodeZigZag(x uint64) int64

DecodeZigZag decodes a zig-zag-encoded uint64 as an int64.

Input:  {…,  5,  3,  1,  0,  2,  4,  6, …}
Output: {…, -3, -2, -1,  0, +1, +2, +3, …}

func EncodeBool

func EncodeBool(x bool) uint64

EncodeBool encodes a bool as a uint64.

Input:  {false, true}
Output: {    0,    1}

func EncodeTag

func EncodeTag(num Number, typ Type) uint64

EncodeTag encodes the field Number and wire Type into its unified form.

func EncodeZigZag

func EncodeZigZag(x int64) uint64

EncodeZigZag encodes an int64 as a zig-zag-encoded uint64.

Input:  {…, -3, -2, -1,  0, +1, +2, +3, …}
Output: {…,  5,  3,  1,  0,  2,  4,  6, …}

func ParseError

func ParseError(n int) error

ParseError converts an error code into an error value. This returns nil if n is a non-negative number.

func SizeBytes

func SizeBytes(n int) int

SizeBytes returns the encoded size of a length-prefixed bytes value, given only the length.

func SizeFixed32

func SizeFixed32() int

SizeFixed32 returns the encoded size of a fixed32; which is always 4.

func SizeFixed64

func SizeFixed64() int

SizeFixed64 returns the encoded size of a fixed64; which is always 8.

func SizeGroup

func SizeGroup(num Number, n int) int

SizeGroup returns the encoded size of a group, given only the length.

func SizeTag

func SizeTag(num Number) int

SizeTag returns the byte size of the encoding.

func SizeVarint

func SizeVarint(v uint64) int

SizeVarint returns the encoded size of a varint. The size is guaranteed to be within 1 and 10, inclusive.

Types

type Number

type Number = int32

Number represents the field number.

const (
	MinValidNumber      Number = 1
	FirstReservedNumber Number = 19000
	LastReservedNumber  Number = 19999
	MaxValidNumber      Number = 1<<29 - 1
)

Number constants

type Type

type Type int8

Type represents the wire type.

const (
	VarintType     Type = 0
	Fixed32Type    Type = 5
	Fixed64Type    Type = 1
	BytesType      Type = 2
	StartGroupType Type = 3
	EndGroupType   Type = 4
)

Type constants

type Visitor

type Visitor interface {
	Varint(Number, uint64)
	Fixed32(Number, uint32)
	Fixed64(Number, uint64)
	Bytes(Number, []byte)
}

Visitor is used to process field values on-line