204 lines
6.1 KiB
Go
204 lines
6.1 KiB
Go
// Go support for Protocol Buffers - Google's data interchange format
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//
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// Copyright 2010 The Go Authors. All rights reserved.
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// https://github.com/golang/protobuf
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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package proto
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/*
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* Routines for encoding data into the wire format for protocol buffers.
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*/
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import (
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"errors"
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"reflect"
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)
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var (
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// errRepeatedHasNil is the error returned if Marshal is called with
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// a struct with a repeated field containing a nil element.
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errRepeatedHasNil = errors.New("proto: repeated field has nil element")
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// errOneofHasNil is the error returned if Marshal is called with
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// a struct with a oneof field containing a nil element.
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errOneofHasNil = errors.New("proto: oneof field has nil value")
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// ErrNil is the error returned if Marshal is called with nil.
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ErrNil = errors.New("proto: Marshal called with nil")
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// ErrTooLarge is the error returned if Marshal is called with a
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// message that encodes to >2GB.
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ErrTooLarge = errors.New("proto: message encodes to over 2 GB")
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)
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// The fundamental encoders that put bytes on the wire.
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// Those that take integer types all accept uint64 and are
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// therefore of type valueEncoder.
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const maxVarintBytes = 10 // maximum length of a varint
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// EncodeVarint returns the varint encoding of x.
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// This is the format for the
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// int32, int64, uint32, uint64, bool, and enum
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// protocol buffer types.
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// Not used by the package itself, but helpful to clients
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// wishing to use the same encoding.
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func EncodeVarint(x uint64) []byte {
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var buf [maxVarintBytes]byte
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var n int
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for n = 0; x > 127; n++ {
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buf[n] = 0x80 | uint8(x&0x7F)
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x >>= 7
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}
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buf[n] = uint8(x)
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n++
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return buf[0:n]
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}
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// EncodeVarint writes a varint-encoded integer to the Buffer.
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// This is the format for the
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// int32, int64, uint32, uint64, bool, and enum
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// protocol buffer types.
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func (p *Buffer) EncodeVarint(x uint64) error {
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for x >= 1<<7 {
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p.buf = append(p.buf, uint8(x&0x7f|0x80))
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x >>= 7
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}
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p.buf = append(p.buf, uint8(x))
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return nil
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}
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// SizeVarint returns the varint encoding size of an integer.
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func SizeVarint(x uint64) int {
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switch {
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case x < 1<<7:
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return 1
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case x < 1<<14:
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return 2
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case x < 1<<21:
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return 3
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case x < 1<<28:
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return 4
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case x < 1<<35:
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return 5
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case x < 1<<42:
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return 6
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case x < 1<<49:
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return 7
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case x < 1<<56:
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return 8
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case x < 1<<63:
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return 9
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}
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return 10
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}
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// EncodeFixed64 writes a 64-bit integer to the Buffer.
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// This is the format for the
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// fixed64, sfixed64, and double protocol buffer types.
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func (p *Buffer) EncodeFixed64(x uint64) error {
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p.buf = append(p.buf,
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uint8(x),
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uint8(x>>8),
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uint8(x>>16),
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uint8(x>>24),
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uint8(x>>32),
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uint8(x>>40),
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uint8(x>>48),
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uint8(x>>56))
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return nil
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}
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// EncodeFixed32 writes a 32-bit integer to the Buffer.
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// This is the format for the
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// fixed32, sfixed32, and float protocol buffer types.
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func (p *Buffer) EncodeFixed32(x uint64) error {
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p.buf = append(p.buf,
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uint8(x),
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uint8(x>>8),
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uint8(x>>16),
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uint8(x>>24))
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return nil
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}
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// EncodeZigzag64 writes a zigzag-encoded 64-bit integer
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// to the Buffer.
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// This is the format used for the sint64 protocol buffer type.
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func (p *Buffer) EncodeZigzag64(x uint64) error {
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// use signed number to get arithmetic right shift.
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return p.EncodeVarint(uint64((x << 1) ^ uint64((int64(x) >> 63))))
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}
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// EncodeZigzag32 writes a zigzag-encoded 32-bit integer
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// to the Buffer.
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// This is the format used for the sint32 protocol buffer type.
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func (p *Buffer) EncodeZigzag32(x uint64) error {
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// use signed number to get arithmetic right shift.
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return p.EncodeVarint(uint64((uint32(x) << 1) ^ uint32((int32(x) >> 31))))
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}
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// EncodeRawBytes writes a count-delimited byte buffer to the Buffer.
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// This is the format used for the bytes protocol buffer
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// type and for embedded messages.
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func (p *Buffer) EncodeRawBytes(b []byte) error {
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p.EncodeVarint(uint64(len(b)))
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p.buf = append(p.buf, b...)
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return nil
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}
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// EncodeStringBytes writes an encoded string to the Buffer.
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// This is the format used for the proto2 string type.
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func (p *Buffer) EncodeStringBytes(s string) error {
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p.EncodeVarint(uint64(len(s)))
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p.buf = append(p.buf, s...)
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return nil
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}
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// Marshaler is the interface representing objects that can marshal themselves.
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type Marshaler interface {
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Marshal() ([]byte, error)
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}
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// EncodeMessage writes the protocol buffer to the Buffer,
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// prefixed by a varint-encoded length.
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func (p *Buffer) EncodeMessage(pb Message) error {
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siz := Size(pb)
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p.EncodeVarint(uint64(siz))
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return p.Marshal(pb)
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}
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// All protocol buffer fields are nillable, but be careful.
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func isNil(v reflect.Value) bool {
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switch v.Kind() {
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case reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice:
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return v.IsNil()
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}
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return false
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}
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