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// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package proto
import (
"errors"
"fmt"
"google.golang.org/protobuf/encoding/prototext"
"google.golang.org/protobuf/encoding/protowire"
"google.golang.org/protobuf/runtime/protoimpl"
)
const (
WireVarint = 0
WireFixed32 = 5
WireFixed64 = 1
WireBytes = 2
WireStartGroup = 3
WireEndGroup = 4
)
// EncodeVarint returns the varint encoded bytes of v.
func EncodeVarint(v uint64) []byte {
return protowire.AppendVarint(nil, v)
}
// SizeVarint returns the length of the varint encoded bytes of v.
// This is equal to len(EncodeVarint(v)).
func SizeVarint(v uint64) int {
return protowire.SizeVarint(v)
}
// DecodeVarint parses a varint encoded integer from b,
// returning the integer value and the length of the varint.
// It returns (0, 0) if there is a parse error.
func DecodeVarint(b []byte) (uint64, int) {
v, n := protowire.ConsumeVarint(b)
if n < 0 {
return 0, 0
}
return v, n
}
// Buffer is a buffer for encoding and decoding the protobuf wire format.
// It may be reused between invocations to reduce memory usage.
type Buffer struct {
buf []byte
idx int
deterministic bool
}
// NewBuffer allocates a new Buffer initialized with buf,
// where the contents of buf are considered the unread portion of the buffer.
func NewBuffer(buf []byte) *Buffer {
return &Buffer{buf: buf}
}
// SetDeterministic specifies whether to use deterministic serialization.
//
// Deterministic serialization guarantees that for a given binary, equal
// messages will always be serialized to the same bytes. This implies:
//
// - Repeated serialization of a message will return the same bytes.
// - Different processes of the same binary (which may be executing on
// different machines) will serialize equal messages to the same bytes.
//
// Note that the deterministic serialization is NOT canonical across
// languages. It is not guaranteed to remain stable over time. It is unstable
// across different builds with schema changes due to unknown fields.
// Users who need canonical serialization (e.g., persistent storage in a
// canonical form, fingerprinting, etc.) should define their own
// canonicalization specification and implement their own serializer rather
// than relying on this API.
//
// If deterministic serialization is requested, map entries will be sorted
// by keys in lexographical order. This is an implementation detail and
// subject to change.
func (b *Buffer) SetDeterministic(deterministic bool) {
b.deterministic = deterministic
}
// SetBuf sets buf as the internal buffer,
// where the contents of buf are considered the unread portion of the buffer.
func (b *Buffer) SetBuf(buf []byte) {
b.buf = buf
b.idx = 0
}
// Reset clears the internal buffer of all written and unread data.
func (b *Buffer) Reset() {
b.buf = b.buf[:0]
b.idx = 0
}
// Bytes returns the internal buffer.
func (b *Buffer) Bytes() []byte {
return b.buf
}
// Unread returns the unread portion of the buffer.
func (b *Buffer) Unread() []byte {
return b.buf[b.idx:]
}
// Marshal appends the wire-format encoding of m to the buffer.
func (b *Buffer) Marshal(m Message) error {
var err error
b.buf, err = marshalAppend(b.buf, m, b.deterministic)
return err
}
// Unmarshal parses the wire-format message in the buffer and
// places the decoded results in m.
// It does not reset m before unmarshaling.
func (b *Buffer) Unmarshal(m Message) error {
err := UnmarshalMerge(b.Unread(), m)
b.idx = len(b.buf)
return err
}
type unknownFields struct{ XXX_unrecognized protoimpl.UnknownFields }
func (m *unknownFields) String() string { panic("not implemented") }
func (m *unknownFields) Reset() { panic("not implemented") }
func (m *unknownFields) ProtoMessage() { panic("not implemented") }
// DebugPrint dumps the encoded bytes of b with a header and footer including s
// to stdout. This is only intended for debugging.
func (*Buffer) DebugPrint(s string, b []byte) {
m := MessageReflect(new(unknownFields))
m.SetUnknown(b)
b, _ = prototext.MarshalOptions{AllowPartial: true, Indent: "\t"}.Marshal(m.Interface())
fmt.Printf("==== %s ====\n%s==== %s ====\n", s, b, s)
}
// EncodeVarint appends an unsigned varint encoding to the buffer.
func (b *Buffer) EncodeVarint(v uint64) error {
b.buf = protowire.AppendVarint(b.buf, v)
return nil
}
// EncodeZigzag32 appends a 32-bit zig-zag varint encoding to the buffer.
func (b *Buffer) EncodeZigzag32(v uint64) error {
return b.EncodeVarint(uint64((uint32(v) << 1) ^ uint32((int32(v) >> 31))))
}
// EncodeZigzag64 appends a 64-bit zig-zag varint encoding to the buffer.
func (b *Buffer) EncodeZigzag64(v uint64) error {
return b.EncodeVarint(uint64((uint64(v) << 1) ^ uint64((int64(v) >> 63))))
}
// EncodeFixed32 appends a 32-bit little-endian integer to the buffer.
func (b *Buffer) EncodeFixed32(v uint64) error {
b.buf = protowire.AppendFixed32(b.buf, uint32(v))
return nil
}
// EncodeFixed64 appends a 64-bit little-endian integer to the buffer.
func (b *Buffer) EncodeFixed64(v uint64) error {
b.buf = protowire.AppendFixed64(b.buf, uint64(v))
return nil
}
// EncodeRawBytes appends a length-prefixed raw bytes to the buffer.
func (b *Buffer) EncodeRawBytes(v []byte) error {
b.buf = protowire.AppendBytes(b.buf, v)
return nil
}
// EncodeStringBytes appends a length-prefixed raw bytes to the buffer.
// It does not validate whether v contains valid UTF-8.
func (b *Buffer) EncodeStringBytes(v string) error {
b.buf = protowire.AppendString(b.buf, v)
return nil
}
// EncodeMessage appends a length-prefixed encoded message to the buffer.
func (b *Buffer) EncodeMessage(m Message) error {
var err error
b.buf = protowire.AppendVarint(b.buf, uint64(Size(m)))
b.buf, err = marshalAppend(b.buf, m, b.deterministic)
return err
}
// DecodeVarint consumes an encoded unsigned varint from the buffer.
func (b *Buffer) DecodeVarint() (uint64, error) {
v, n := protowire.ConsumeVarint(b.buf[b.idx:])
if n < 0 {
return 0, protowire.ParseError(n)
}
b.idx += n
return uint64(v), nil
}
// DecodeZigzag32 consumes an encoded 32-bit zig-zag varint from the buffer.
func (b *Buffer) DecodeZigzag32() (uint64, error) {
v, err := b.DecodeVarint()
if err != nil {
return 0, err
}
return uint64((uint32(v) >> 1) ^ uint32((int32(v&1)<<31)>>31)), nil
}
// DecodeZigzag64 consumes an encoded 64-bit zig-zag varint from the buffer.
func (b *Buffer) DecodeZigzag64() (uint64, error) {
v, err := b.DecodeVarint()
if err != nil {
return 0, err
}
return uint64((uint64(v) >> 1) ^ uint64((int64(v&1)<<63)>>63)), nil
}
// DecodeFixed32 consumes a 32-bit little-endian integer from the buffer.
func (b *Buffer) DecodeFixed32() (uint64, error) {
v, n := protowire.ConsumeFixed32(b.buf[b.idx:])
if n < 0 {
return 0, protowire.ParseError(n)
}
b.idx += n
return uint64(v), nil
}
// DecodeFixed64 consumes a 64-bit little-endian integer from the buffer.
func (b *Buffer) DecodeFixed64() (uint64, error) {
v, n := protowire.ConsumeFixed64(b.buf[b.idx:])
if n < 0 {
return 0, protowire.ParseError(n)
}
b.idx += n
return uint64(v), nil
}
// DecodeRawBytes consumes a length-prefixed raw bytes from the buffer.
// If alloc is specified, it returns a copy the raw bytes
// rather than a sub-slice of the buffer.
func (b *Buffer) DecodeRawBytes(alloc bool) ([]byte, error) {
v, n := protowire.ConsumeBytes(b.buf[b.idx:])
if n < 0 {
return nil, protowire.ParseError(n)
}
b.idx += n
if alloc {
v = append([]byte(nil), v...)
}
return v, nil
}
// DecodeStringBytes consumes a length-prefixed raw bytes from the buffer.
// It does not validate whether the raw bytes contain valid UTF-8.
func (b *Buffer) DecodeStringBytes() (string, error) {
v, n := protowire.ConsumeString(b.buf[b.idx:])
if n < 0 {
return "", protowire.ParseError(n)
}
b.idx += n
return v, nil
}
// DecodeMessage consumes a length-prefixed message from the buffer.
// It does not reset m before unmarshaling.
func (b *Buffer) DecodeMessage(m Message) error {
v, err := b.DecodeRawBytes(false)
if err != nil {
return err
}
return UnmarshalMerge(v, m)
}
// DecodeGroup consumes a message group from the buffer.
// It assumes that the start group marker has already been consumed and
// consumes all bytes until (and including the end group marker).
// It does not reset m before unmarshaling.
func (b *Buffer) DecodeGroup(m Message) error {
v, n, err := consumeGroup(b.buf[b.idx:])
if err != nil {
return err
}
b.idx += n
return UnmarshalMerge(v, m)
}
// consumeGroup parses b until it finds an end group marker, returning
// the raw bytes of the message (excluding the end group marker) and the
// the total length of the message (including the end group marker).
func consumeGroup(b []byte) ([]byte, int, error) {
b0 := b
depth := 1 // assume this follows a start group marker
for {
_, wtyp, tagLen := protowire.ConsumeTag(b)
if tagLen < 0 {
return nil, 0, protowire.ParseError(tagLen)
}
b = b[tagLen:]
var valLen int
switch wtyp {
case protowire.VarintType:
_, valLen = protowire.ConsumeVarint(b)
case protowire.Fixed32Type:
_, valLen = protowire.ConsumeFixed32(b)
case protowire.Fixed64Type:
_, valLen = protowire.ConsumeFixed64(b)
case protowire.BytesType:
_, valLen = protowire.ConsumeBytes(b)
case protowire.StartGroupType:
depth++
case protowire.EndGroupType:
depth--
default:
return nil, 0, errors.New("proto: cannot parse reserved wire type")
}
if valLen < 0 {
return nil, 0, protowire.ParseError(valLen)
}
b = b[valLen:]
if depth == 0 {
return b0[:len(b0)-len(b)-tagLen], len(b0) - len(b), nil
}
}
}
