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