diff --git a/internal/legacy/file.go b/internal/legacy/file.go
index d76255b..606327f 100644
--- a/internal/legacy/file.go
+++ b/internal/legacy/file.go
@@ -13,9 +13,9 @@
 	// TODO: Avoid reliance on old API. However, there is currently a
 	// chicken and egg problem where we need the descriptor protos to implement
 	// the new API.
-	protoV1 "github.com/golang/protobuf/proto"
-	pref "github.com/golang/protobuf/v2/reflect/protoreflect"
+	protoV1 "github.com/golang/protobuf/v2/internal/legacy/protoV1"
 
+	pref "github.com/golang/protobuf/v2/reflect/protoreflect"
 	descriptorpb "github.com/golang/protobuf/v2/types/descriptor"
 )
 
diff --git a/internal/legacy/protoV1/decode.go b/internal/legacy/protoV1/decode.go
new file mode 100644
index 0000000..caa9f17
--- /dev/null
+++ b/internal/legacy/protoV1/decode.go
@@ -0,0 +1,85 @@
+// Copyright 2010 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 protoV1
+
+// Unmarshaler is the interface representing objects that can
+// unmarshal themselves.  The argument points to data that may be
+// overwritten, so implementations should not keep references to the
+// buffer.
+// Unmarshal implementations should not clear the receiver.
+// Any unmarshaled data should be merged into the receiver.
+// Callers of Unmarshal that do not want to retain existing data
+// should Reset the receiver before calling Unmarshal.
+type Unmarshaler interface {
+	Unmarshal([]byte) error
+}
+
+// newUnmarshaler is the interface representing objects that can
+// unmarshal themselves. The semantics are identical to Unmarshaler.
+//
+// This exists to support protoc-gen-go generated messages.
+// The proto package will stop type-asserting to this interface in the future.
+//
+// DO NOT DEPEND ON THIS.
+type newUnmarshaler interface {
+	XXX_Unmarshal([]byte) error
+}
+
+// Unmarshal parses the protocol buffer representation in buf and places the
+// decoded result in pb.  If the struct underlying pb does not match
+// the data in buf, the results can be unpredictable.
+//
+// Unmarshal resets pb before starting to unmarshal, so any
+// existing data in pb is always removed. Use UnmarshalMerge
+// to preserve and append to existing data.
+func Unmarshal(buf []byte, pb Message) error {
+	pb.Reset()
+	if u, ok := pb.(newUnmarshaler); ok {
+		return u.XXX_Unmarshal(buf)
+	}
+	if u, ok := pb.(Unmarshaler); ok {
+		return u.Unmarshal(buf)
+	}
+	return NewBuffer(buf).Unmarshal(pb)
+}
+
+// Unmarshal parses the protocol buffer representation in the
+// Buffer and places the decoded result in pb.  If the struct
+// underlying pb does not match the data in the buffer, the results can be
+// unpredictable.
+//
+// Unlike proto.Unmarshal, this does not reset pb before starting to unmarshal.
+func (p *Buffer) Unmarshal(pb Message) error {
+	// If the object can unmarshal itself, let it.
+	if u, ok := pb.(newUnmarshaler); ok {
+		err := u.XXX_Unmarshal(p.buf[p.index:])
+		p.index = len(p.buf)
+		return err
+	}
+	if u, ok := pb.(Unmarshaler); ok {
+		// NOTE: The history of proto have unfortunately been inconsistent
+		// whether Unmarshaler should or should not implicitly clear itself.
+		// Some implementations do, most do not.
+		// Thus, calling this here may or may not do what people want.
+		//
+		// See https://github.com/golang/protobuf/issues/424
+		err := u.Unmarshal(p.buf[p.index:])
+		p.index = len(p.buf)
+		return err
+	}
+
+	// Slow workaround for messages that aren't Unmarshalers.
+	// This includes some hand-coded .pb.go files and
+	// bootstrap protos.
+	// TODO: fix all of those and then add Unmarshal to
+	// the Message interface. Then:
+	// The cast above and code below can be deleted.
+	// The old unmarshaler can be deleted.
+	// Clients can call Unmarshal directly (can already do that, actually).
+	var info InternalMessageInfo
+	err := info.Unmarshal(pb, p.buf[p.index:])
+	p.index = len(p.buf)
+	return err
+}
diff --git a/internal/legacy/protoV1/lib.go b/internal/legacy/protoV1/lib.go
new file mode 100644
index 0000000..b5c2de6
--- /dev/null
+++ b/internal/legacy/protoV1/lib.go
@@ -0,0 +1,102 @@
+// Copyright 2010 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 protoV1
+
+import (
+	"fmt"
+
+	"github.com/golang/protobuf/protoapi"
+)
+
+// RequiredNotSetError is an error type returned by either Marshal or Unmarshal.
+// Marshal reports this when a required field is not initialized.
+// Unmarshal reports this when a required field is missing from the wire data.
+type RequiredNotSetError struct{ field string }
+
+func (e *RequiredNotSetError) Error() string {
+	if e.field == "" {
+		return fmt.Sprintf("proto: required field not set")
+	}
+	return fmt.Sprintf("proto: required field %q not set", e.field)
+}
+func (e *RequiredNotSetError) RequiredNotSet() bool {
+	return true
+}
+
+type invalidUTF8Error struct{ field string }
+
+func (e *invalidUTF8Error) Error() string {
+	if e.field == "" {
+		return "proto: invalid UTF-8 detected"
+	}
+	return fmt.Sprintf("proto: field %q contains invalid UTF-8", e.field)
+}
+func (e *invalidUTF8Error) InvalidUTF8() bool {
+	return true
+}
+
+// errInvalidUTF8 is a sentinel error to identify fields with invalid UTF-8.
+// This error should not be exposed to the external API as such errors should
+// be recreated with the field information.
+var errInvalidUTF8 = &invalidUTF8Error{}
+
+// isNonFatal reports whether the error is either a RequiredNotSet error
+// or a InvalidUTF8 error.
+func isNonFatal(err error) bool {
+	if re, ok := err.(interface{ RequiredNotSet() bool }); ok && re.RequiredNotSet() {
+		return true
+	}
+	if re, ok := err.(interface{ InvalidUTF8() bool }); ok && re.InvalidUTF8() {
+		return true
+	}
+	return false
+}
+
+type nonFatal struct{ E error }
+
+// Merge merges err into nf and reports whether it was successful.
+// Otherwise it returns false for any fatal non-nil errors.
+func (nf *nonFatal) Merge(err error) (ok bool) {
+	if err == nil {
+		return true // not an error
+	}
+	if !isNonFatal(err) {
+		return false // fatal error
+	}
+	if nf.E == nil {
+		nf.E = err // store first instance of non-fatal error
+	}
+	return true
+}
+
+type (
+	Message                = protoapi.Message
+	Extension              = protoapi.ExtensionField
+	ExtensionRange         = protoapi.ExtensionRange
+	XXX_InternalExtensions = protoapi.XXX_InternalExtensions
+)
+
+// A Buffer is a buffer manager for marshaling and unmarshaling
+// protocol buffers.  It may be reused between invocations to
+// reduce memory usage.  It is not necessary to use a Buffer;
+// the global functions Marshal and Unmarshal create a
+// temporary Buffer and are fine for most applications.
+type Buffer struct {
+	buf   []byte // encode/decode byte stream
+	index int    // read point
+}
+
+// NewBuffer allocates a new Buffer and initializes its internal data to
+// the contents of the argument slice.
+func NewBuffer(e []byte) *Buffer {
+	return &Buffer{buf: e}
+}
+
+// InternalMessageInfo is a type used internally by generated .pb.go files.
+// This type is not intended to be used by non-generated code.
+// This type is not subject to any compatibility guarantee.
+type InternalMessageInfo struct {
+	unmarshal *unmarshalInfo
+}
diff --git a/internal/legacy/protoV1/pointer_reflect.go b/internal/legacy/protoV1/pointer_reflect.go
new file mode 100644
index 0000000..85adcd2
--- /dev/null
+++ b/internal/legacy/protoV1/pointer_reflect.go
@@ -0,0 +1,207 @@
+// Copyright 2012 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.
+
+// +build purego
+
+package protoV1
+
+import (
+	"reflect"
+	"sync"
+
+	"github.com/golang/protobuf/protoapi"
+)
+
+// A field identifies a field in a struct, accessible from a pointer.
+// In this implementation, a field is identified by the sequence of field indices
+// passed to reflect's FieldByIndex.
+type field []int
+
+// toField returns a field equivalent to the given reflect field.
+func toField(f *reflect.StructField) field {
+	return f.Index
+}
+
+// invalidField is an invalid field identifier.
+var invalidField = field(nil)
+
+// zeroField is a noop when calling pointer.offset.
+var zeroField = field([]int{})
+
+// IsValid reports whether the field identifier is valid.
+func (f field) IsValid() bool { return f != nil }
+
+// The pointer type is for the table-driven decoder.
+// The implementation here uses a reflect.Value of pointer type to
+// create a generic pointer. In pointer_unsafe.go we use unsafe
+// instead of reflect to implement the same (but faster) interface.
+type pointer struct {
+	v reflect.Value
+}
+
+// toPointer converts an interface of pointer type to a pointer
+// that points to the same target.
+func toPointer(i *Message) pointer {
+	return pointer{v: reflect.ValueOf(*i)}
+}
+
+// valToPointer converts v to a pointer.  v must be of pointer type.
+func valToPointer(v reflect.Value) pointer {
+	return pointer{v: v}
+}
+
+// offset converts from a pointer to a structure to a pointer to
+// one of its fields.
+func (p pointer) offset(f field) pointer {
+	return pointer{v: p.v.Elem().FieldByIndex(f).Addr()}
+}
+
+func (p pointer) isNil() bool {
+	return p.v.IsNil()
+}
+
+// grow updates the slice s in place to make it one element longer.
+// s must be addressable.
+// Returns the (addressable) new element.
+func grow(s reflect.Value) reflect.Value {
+	n, m := s.Len(), s.Cap()
+	if n < m {
+		s.SetLen(n + 1)
+	} else {
+		s.Set(reflect.Append(s, reflect.Zero(s.Type().Elem())))
+	}
+	return s.Index(n)
+}
+
+func (p pointer) toInt64() *int64 {
+	return p.v.Interface().(*int64)
+}
+func (p pointer) toInt64Ptr() **int64 {
+	return p.v.Interface().(**int64)
+}
+func (p pointer) toInt64Slice() *[]int64 {
+	return p.v.Interface().(*[]int64)
+}
+
+var int32ptr = reflect.TypeOf((*int32)(nil))
+
+func (p pointer) toInt32() *int32 {
+	return p.v.Convert(int32ptr).Interface().(*int32)
+}
+
+// The toInt32Ptr/Slice methods don't work because of enums.
+// Instead, we must use set/get methods for the int32ptr/slice case.
+/*
+	func (p pointer) toInt32Ptr() **int32 {
+		return p.v.Interface().(**int32)
+}
+	func (p pointer) toInt32Slice() *[]int32 {
+		return p.v.Interface().(*[]int32)
+}
+*/
+func (p pointer) setInt32Ptr(v int32) {
+	// Allocate value in a *int32. Possibly convert that to a *enum.
+	// Then assign it to a **int32 or **enum.
+	// Note: we can convert *int32 to *enum, but we can't convert
+	// **int32 to **enum!
+	p.v.Elem().Set(reflect.ValueOf(&v).Convert(p.v.Type().Elem()))
+}
+
+func (p pointer) appendInt32Slice(v int32) {
+	grow(p.v.Elem()).SetInt(int64(v))
+}
+
+func (p pointer) toUint64() *uint64 {
+	return p.v.Interface().(*uint64)
+}
+func (p pointer) toUint64Ptr() **uint64 {
+	return p.v.Interface().(**uint64)
+}
+func (p pointer) toUint64Slice() *[]uint64 {
+	return p.v.Interface().(*[]uint64)
+}
+func (p pointer) toUint32() *uint32 {
+	return p.v.Interface().(*uint32)
+}
+func (p pointer) toUint32Ptr() **uint32 {
+	return p.v.Interface().(**uint32)
+}
+func (p pointer) toUint32Slice() *[]uint32 {
+	return p.v.Interface().(*[]uint32)
+}
+func (p pointer) toBool() *bool {
+	return p.v.Interface().(*bool)
+}
+func (p pointer) toBoolPtr() **bool {
+	return p.v.Interface().(**bool)
+}
+func (p pointer) toBoolSlice() *[]bool {
+	return p.v.Interface().(*[]bool)
+}
+func (p pointer) toFloat64() *float64 {
+	return p.v.Interface().(*float64)
+}
+func (p pointer) toFloat64Ptr() **float64 {
+	return p.v.Interface().(**float64)
+}
+func (p pointer) toFloat64Slice() *[]float64 {
+	return p.v.Interface().(*[]float64)
+}
+func (p pointer) toFloat32() *float32 {
+	return p.v.Interface().(*float32)
+}
+func (p pointer) toFloat32Ptr() **float32 {
+	return p.v.Interface().(**float32)
+}
+func (p pointer) toFloat32Slice() *[]float32 {
+	return p.v.Interface().(*[]float32)
+}
+func (p pointer) toString() *string {
+	return p.v.Interface().(*string)
+}
+func (p pointer) toStringPtr() **string {
+	return p.v.Interface().(**string)
+}
+func (p pointer) toStringSlice() *[]string {
+	return p.v.Interface().(*[]string)
+}
+func (p pointer) toBytes() *[]byte {
+	return p.v.Interface().(*[]byte)
+}
+func (p pointer) toBytesSlice() *[][]byte {
+	return p.v.Interface().(*[][]byte)
+}
+func (p pointer) toExtensions() *protoapi.XXX_InternalExtensions {
+	return p.v.Interface().(*protoapi.XXX_InternalExtensions)
+}
+func (p pointer) toOldExtensions() *map[int32]protoapi.ExtensionField {
+	return p.v.Interface().(*map[int32]protoapi.ExtensionField)
+}
+func (p pointer) getPointer() pointer {
+	return pointer{v: p.v.Elem()}
+}
+func (p pointer) setPointer(q pointer) {
+	p.v.Elem().Set(q.v)
+}
+func (p pointer) appendPointer(q pointer) {
+	grow(p.v.Elem()).Set(q.v)
+}
+
+func (p pointer) asPointerTo(t reflect.Type) reflect.Value {
+	// TODO: check that p.v.Type().Elem() == t?
+	return p.v
+}
+
+func atomicLoadUnmarshalInfo(p **unmarshalInfo) *unmarshalInfo {
+	atomicLock.Lock()
+	defer atomicLock.Unlock()
+	return *p
+}
+func atomicStoreUnmarshalInfo(p **unmarshalInfo, v *unmarshalInfo) {
+	atomicLock.Lock()
+	defer atomicLock.Unlock()
+	*p = v
+}
+
+var atomicLock sync.Mutex
diff --git a/internal/legacy/protoV1/pointer_unsafe.go b/internal/legacy/protoV1/pointer_unsafe.go
new file mode 100644
index 0000000..7b69878
--- /dev/null
+++ b/internal/legacy/protoV1/pointer_unsafe.go
@@ -0,0 +1,202 @@
+// Copyright 2012 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.
+
+// +build !purego
+
+package protoV1
+
+import (
+	"reflect"
+	"sync/atomic"
+	"unsafe"
+
+	"github.com/golang/protobuf/protoapi"
+)
+
+// A field identifies a field in a struct, accessible from a pointer.
+// In this implementation, a field is identified by its byte offset from the start of the struct.
+type field uintptr
+
+// toField returns a field equivalent to the given reflect field.
+func toField(f *reflect.StructField) field {
+	return field(f.Offset)
+}
+
+// invalidField is an invalid field identifier.
+const invalidField = ^field(0)
+
+// zeroField is a noop when calling pointer.offset.
+const zeroField = field(0)
+
+// IsValid reports whether the field identifier is valid.
+func (f field) IsValid() bool {
+	return f != invalidField
+}
+
+// The pointer type below is for the new table-driven encoder/decoder.
+// The implementation here uses unsafe.Pointer to create a generic pointer.
+// In pointer_reflect.go we use reflect instead of unsafe to implement
+// the same (but slower) interface.
+type pointer struct {
+	p unsafe.Pointer
+}
+
+// toPointer converts an interface of pointer type to a pointer
+// that points to the same target.
+func toPointer(i *Message) pointer {
+	// Super-tricky - read pointer out of data word of interface value.
+	// Saves ~25ns over the equivalent:
+	// return valToPointer(reflect.ValueOf(*i))
+	return pointer{p: (*[2]unsafe.Pointer)(unsafe.Pointer(i))[1]}
+}
+
+// valToPointer converts v to a pointer. v must be of pointer type.
+func valToPointer(v reflect.Value) pointer {
+	return pointer{p: unsafe.Pointer(v.Pointer())}
+}
+
+// offset converts from a pointer to a structure to a pointer to
+// one of its fields.
+func (p pointer) offset(f field) pointer {
+	// For safety, we should panic if !f.IsValid, however calling panic causes
+	// this to no longer be inlineable, which is a serious performance cost.
+	/*
+		if !f.IsValid() {
+			panic("invalid field")
+		}
+	*/
+	return pointer{p: unsafe.Pointer(uintptr(p.p) + uintptr(f))}
+}
+
+func (p pointer) isNil() bool {
+	return p.p == nil
+}
+
+func (p pointer) toInt64() *int64 {
+	return (*int64)(p.p)
+}
+func (p pointer) toInt64Ptr() **int64 {
+	return (**int64)(p.p)
+}
+func (p pointer) toInt64Slice() *[]int64 {
+	return (*[]int64)(p.p)
+}
+func (p pointer) toInt32() *int32 {
+	return (*int32)(p.p)
+}
+
+// See pointer_reflect.go for why toInt32Ptr/Slice doesn't exist.
+/*
+	func (p pointer) toInt32Ptr() **int32 {
+		return (**int32)(p.p)
+	}
+	func (p pointer) toInt32Slice() *[]int32 {
+		return (*[]int32)(p.p)
+	}
+*/
+func (p pointer) setInt32Ptr(v int32) {
+	*(**int32)(p.p) = &v
+}
+
+// TODO: Can we get rid of appendInt32Slice and use setInt32Slice instead?
+func (p pointer) appendInt32Slice(v int32) {
+	s := (*[]int32)(p.p)
+	*s = append(*s, v)
+}
+
+func (p pointer) toUint64() *uint64 {
+	return (*uint64)(p.p)
+}
+func (p pointer) toUint64Ptr() **uint64 {
+	return (**uint64)(p.p)
+}
+func (p pointer) toUint64Slice() *[]uint64 {
+	return (*[]uint64)(p.p)
+}
+func (p pointer) toUint32() *uint32 {
+	return (*uint32)(p.p)
+}
+func (p pointer) toUint32Ptr() **uint32 {
+	return (**uint32)(p.p)
+}
+func (p pointer) toUint32Slice() *[]uint32 {
+	return (*[]uint32)(p.p)
+}
+func (p pointer) toBool() *bool {
+	return (*bool)(p.p)
+}
+func (p pointer) toBoolPtr() **bool {
+	return (**bool)(p.p)
+}
+func (p pointer) toBoolSlice() *[]bool {
+	return (*[]bool)(p.p)
+}
+func (p pointer) toFloat64() *float64 {
+	return (*float64)(p.p)
+}
+func (p pointer) toFloat64Ptr() **float64 {
+	return (**float64)(p.p)
+}
+func (p pointer) toFloat64Slice() *[]float64 {
+	return (*[]float64)(p.p)
+}
+func (p pointer) toFloat32() *float32 {
+	return (*float32)(p.p)
+}
+func (p pointer) toFloat32Ptr() **float32 {
+	return (**float32)(p.p)
+}
+func (p pointer) toFloat32Slice() *[]float32 {
+	return (*[]float32)(p.p)
+}
+func (p pointer) toString() *string {
+	return (*string)(p.p)
+}
+func (p pointer) toStringPtr() **string {
+	return (**string)(p.p)
+}
+func (p pointer) toStringSlice() *[]string {
+	return (*[]string)(p.p)
+}
+func (p pointer) toBytes() *[]byte {
+	return (*[]byte)(p.p)
+}
+func (p pointer) toBytesSlice() *[][]byte {
+	return (*[][]byte)(p.p)
+}
+func (p pointer) toExtensions() *protoapi.XXX_InternalExtensions {
+	return (*protoapi.XXX_InternalExtensions)(p.p)
+}
+func (p pointer) toOldExtensions() *map[int32]protoapi.ExtensionField {
+	return (*map[int32]protoapi.ExtensionField)(p.p)
+}
+
+// getPointer loads the pointer at p and returns it.
+func (p pointer) getPointer() pointer {
+	return pointer{p: *(*unsafe.Pointer)(p.p)}
+}
+
+// setPointer stores the pointer q at p.
+func (p pointer) setPointer(q pointer) {
+	*(*unsafe.Pointer)(p.p) = q.p
+}
+
+// append q to the slice pointed to by p.
+func (p pointer) appendPointer(q pointer) {
+	s := (*[]unsafe.Pointer)(p.p)
+	*s = append(*s, q.p)
+}
+
+// asPointerTo returns a reflect.Value that is a pointer to an
+// object of type t stored at p.
+func (p pointer) asPointerTo(t reflect.Type) reflect.Value {
+	return reflect.NewAt(t, p.p)
+}
+
+func atomicLoadUnmarshalInfo(p **unmarshalInfo) *unmarshalInfo {
+	return (*unmarshalInfo)(atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(p))))
+}
+func atomicStoreUnmarshalInfo(p **unmarshalInfo, v *unmarshalInfo) {
+	atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(p)), unsafe.Pointer(v))
+}
diff --git a/internal/legacy/protoV1/properties.go b/internal/legacy/protoV1/properties.go
new file mode 100644
index 0000000..c4aad8f
--- /dev/null
+++ b/internal/legacy/protoV1/properties.go
@@ -0,0 +1,24 @@
+// Copyright 2010 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 protoV1
+
+// Constants that identify the encoding of a value on the wire.
+const (
+	WireVarint     = 0
+	WireFixed64    = 1
+	WireBytes      = 2
+	WireStartGroup = 3
+	WireEndGroup   = 4
+	WireFixed32    = 5
+)
+
+type (
+	oneofFuncsIface interface {
+		XXX_OneofFuncs() (func(Message, *Buffer) error, func(Message, int, int, *Buffer) (bool, error), func(Message) int, []interface{})
+	}
+	oneofWrappersIface interface {
+		XXX_OneofWrappers() []interface{}
+	}
+)
diff --git a/internal/legacy/protoV1/table_unmarshal.go b/internal/legacy/protoV1/table_unmarshal.go
new file mode 100644
index 0000000..e7417a1
--- /dev/null
+++ b/internal/legacy/protoV1/table_unmarshal.go
@@ -0,0 +1,2025 @@
+// Copyright 2016 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 protoV1
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"math"
+	"reflect"
+	"strconv"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"unicode/utf8"
+
+	"github.com/golang/protobuf/protoapi"
+	"github.com/golang/protobuf/v2/reflect/protoreflect"
+)
+
+// Unmarshal is the entry point from the generated .pb.go files.
+// This function is not intended to be used by non-generated code.
+// This function is not subject to any compatibility guarantee.
+// msg contains a pointer to a protocol buffer struct.
+// b is the data to be unmarshaled into the protocol buffer.
+// a is a pointer to a place to store cached unmarshal information.
+func (a *InternalMessageInfo) Unmarshal(msg Message, b []byte) error {
+	// Load the unmarshal information for this message type.
+	// The atomic load ensures memory consistency.
+	u := atomicLoadUnmarshalInfo(&a.unmarshal)
+	if u == nil {
+		// Slow path: find unmarshal info for msg, update a with it.
+		u = getUnmarshalInfo(reflect.TypeOf(msg).Elem())
+		atomicStoreUnmarshalInfo(&a.unmarshal, u)
+	}
+	// Then do the unmarshaling.
+	err := u.unmarshal(toPointer(&msg), b)
+	return err
+}
+
+type unmarshalInfo struct {
+	typ reflect.Type // type of the protobuf struct
+
+	// 0 = only typ field is initialized
+	// 1 = completely initialized
+	initialized     int32
+	lock            sync.Mutex                    // prevents double initialization
+	dense           []unmarshalFieldInfo          // fields indexed by tag #
+	sparse          map[uint64]unmarshalFieldInfo // fields indexed by tag #
+	reqFields       []string                      // names of required fields
+	reqMask         uint64                        // 1<<len(reqFields)-1
+	unrecognized    field                         // offset of []byte to put unrecognized data (or invalidField if we should throw it away)
+	extensions      field                         // offset of extensions field (of type proto.XXX_InternalExtensions), or invalidField if it does not exist
+	oldExtensions   field                         // offset of old-form extensions field (of type map[int]Extension)
+	extensionRanges []ExtensionRange              // if non-nil, implies extensions field is valid
+	isMessageSet    bool                          // if true, implies extensions field is valid
+}
+
+// An unmarshaler takes a stream of bytes and a pointer to a field of a message.
+// It decodes the field, stores it at f, and returns the unused bytes.
+// w is the wire encoding.
+// b is the data after the tag and wire encoding have been read.
+type unmarshaler func(b []byte, f pointer, w int) ([]byte, error)
+
+type unmarshalFieldInfo struct {
+	// location of the field in the proto message structure.
+	field field
+
+	// function to unmarshal the data for the field.
+	unmarshal unmarshaler
+
+	// if a required field, contains a single set bit at this field's index in the required field list.
+	reqMask uint64
+
+	name string // name of the field, for error reporting
+}
+
+var (
+	unmarshalInfoMap  = map[reflect.Type]*unmarshalInfo{}
+	unmarshalInfoLock sync.Mutex
+)
+
+// getUnmarshalInfo returns the data structure which can be
+// subsequently used to unmarshal a message of the given type.
+// t is the type of the message (note: not pointer to message).
+func getUnmarshalInfo(t reflect.Type) *unmarshalInfo {
+	// It would be correct to return a new unmarshalInfo
+	// unconditionally. We would end up allocating one
+	// per occurrence of that type as a message or submessage.
+	// We use a cache here just to reduce memory usage.
+	unmarshalInfoLock.Lock()
+	defer unmarshalInfoLock.Unlock()
+	u := unmarshalInfoMap[t]
+	if u == nil {
+		u = &unmarshalInfo{typ: t}
+		// Note: we just set the type here. The rest of the fields
+		// will be initialized on first use.
+		unmarshalInfoMap[t] = u
+	}
+	return u
+}
+
+// unmarshal does the main work of unmarshaling a message.
+// u provides type information used to unmarshal the message.
+// m is a pointer to a protocol buffer message.
+// b is a byte stream to unmarshal into m.
+// This is top routine used when recursively unmarshaling submessages.
+func (u *unmarshalInfo) unmarshal(m pointer, b []byte) error {
+	if atomic.LoadInt32(&u.initialized) == 0 {
+		u.computeUnmarshalInfo()
+	}
+	if u.isMessageSet {
+		panic("message sets not supported")
+	}
+	var reqMask uint64 // bitmask of required fields we've seen.
+	var errLater error
+	for len(b) > 0 {
+		// Read tag and wire type.
+		// Special case 1 and 2 byte varints.
+		var x uint64
+		if b[0] < 128 {
+			x = uint64(b[0])
+			b = b[1:]
+		} else if len(b) >= 2 && b[1] < 128 {
+			x = uint64(b[0]&0x7f) + uint64(b[1])<<7
+			b = b[2:]
+		} else {
+			var n int
+			x, n = decodeVarint(b)
+			if n == 0 {
+				return io.ErrUnexpectedEOF
+			}
+			b = b[n:]
+		}
+		tag := x >> 3
+		wire := int(x) & 7
+
+		// Dispatch on the tag to one of the unmarshal* functions below.
+		var f unmarshalFieldInfo
+		if tag < uint64(len(u.dense)) {
+			f = u.dense[tag]
+		} else {
+			f = u.sparse[tag]
+		}
+		if fn := f.unmarshal; fn != nil {
+			var err error
+			b, err = fn(b, m.offset(f.field), wire)
+			if err == nil {
+				reqMask |= f.reqMask
+				continue
+			}
+			if r, ok := err.(*RequiredNotSetError); ok {
+				// Remember this error, but keep parsing. We need to produce
+				// a full parse even if a required field is missing.
+				if errLater == nil {
+					errLater = r
+				}
+				reqMask |= f.reqMask
+				continue
+			}
+			if err != errInternalBadWireType {
+				if err == errInvalidUTF8 {
+					if errLater == nil {
+						fullName := "protobuf full names not supported"
+						errLater = &invalidUTF8Error{fullName}
+					}
+					continue
+				}
+				return err
+			}
+			// Fragments with bad wire type are treated as unknown fields.
+		}
+
+		// Unknown tag.
+		if !u.unrecognized.IsValid() {
+			// Don't keep unrecognized data; just skip it.
+			var err error
+			b, err = skipField(b, wire)
+			if err != nil {
+				return err
+			}
+			continue
+		}
+		// Keep unrecognized data around.
+		// maybe in extensions, maybe in the unrecognized field.
+		z := m.offset(u.unrecognized).toBytes()
+		var emap protoapi.ExtensionFields
+		var e Extension
+		for _, r := range u.extensionRanges {
+			if uint64(r.Start) <= tag && tag <= uint64(r.End) {
+				if u.extensions.IsValid() {
+					mp := m.offset(u.extensions).toExtensions()
+					emap = protoapi.ExtensionFieldsOf(mp)
+					e = emap.Get(protoreflect.FieldNumber(tag))
+					z = &e.Raw
+					break
+				}
+				if u.oldExtensions.IsValid() {
+					p := m.offset(u.oldExtensions).toOldExtensions()
+					emap = protoapi.ExtensionFieldsOf(p)
+					e = emap.Get(protoreflect.FieldNumber(tag))
+					z = &e.Raw
+					break
+				}
+				panic("no extensions field available")
+			}
+		}
+
+		// Use wire type to skip data.
+		var err error
+		b0 := b
+		b, err = skipField(b, wire)
+		if err != nil {
+			return err
+		}
+		*z = encodeVarint(*z, tag<<3|uint64(wire))
+		*z = append(*z, b0[:len(b0)-len(b)]...)
+
+		if emap != nil {
+			emap.Set(protoreflect.FieldNumber(tag), e)
+		}
+	}
+	if reqMask != u.reqMask && errLater == nil {
+		// A required field of this message is missing.
+		for _, n := range u.reqFields {
+			if reqMask&1 == 0 {
+				errLater = &RequiredNotSetError{n}
+			}
+			reqMask >>= 1
+		}
+	}
+	return errLater
+}
+
+// computeUnmarshalInfo fills in u with information for use
+// in unmarshaling protocol buffers of type u.typ.
+func (u *unmarshalInfo) computeUnmarshalInfo() {
+	u.lock.Lock()
+	defer u.lock.Unlock()
+	if u.initialized != 0 {
+		return
+	}
+	t := u.typ
+	n := t.NumField()
+
+	// Set up the "not found" value for the unrecognized byte buffer.
+	// This is the default for proto3.
+	u.unrecognized = invalidField
+	u.extensions = invalidField
+	u.oldExtensions = invalidField
+
+	// List of the generated type and offset for each oneof field.
+	type oneofField struct {
+		ityp  reflect.Type // interface type of oneof field
+		field field        // offset in containing message
+	}
+	var oneofFields []oneofField
+
+	for i := 0; i < n; i++ {
+		f := t.Field(i)
+		if f.Name == "XXX_unrecognized" {
+			// The byte slice used to hold unrecognized input is special.
+			if f.Type != reflect.TypeOf(([]byte)(nil)) {
+				panic("bad type for XXX_unrecognized field: " + f.Type.Name())
+			}
+			u.unrecognized = toField(&f)
+			continue
+		}
+		if f.Name == "XXX_InternalExtensions" {
+			// Ditto here.
+			if f.Type != reflect.TypeOf(XXX_InternalExtensions{}) {
+				panic("bad type for XXX_InternalExtensions field: " + f.Type.Name())
+			}
+			u.extensions = toField(&f)
+			if f.Tag.Get("protobuf_messageset") == "1" {
+				u.isMessageSet = true
+			}
+			continue
+		}
+		if f.Name == "XXX_extensions" {
+			// An older form of the extensions field.
+			if f.Type != reflect.TypeOf((map[int32]Extension)(nil)) {
+				panic("bad type for XXX_extensions field: " + f.Type.Name())
+			}
+			u.oldExtensions = toField(&f)
+			continue
+		}
+		if f.Name == "XXX_NoUnkeyedLiteral" || f.Name == "XXX_sizecache" {
+			continue
+		}
+
+		oneof := f.Tag.Get("protobuf_oneof")
+		if oneof != "" {
+			oneofFields = append(oneofFields, oneofField{f.Type, toField(&f)})
+			// The rest of oneof processing happens below.
+			continue
+		}
+
+		tags := f.Tag.Get("protobuf")
+		tagArray := strings.Split(tags, ",")
+		if len(tagArray) < 2 {
+			panic("protobuf tag not enough fields in " + t.Name() + "." + f.Name + ": " + tags)
+		}
+		tag, err := strconv.Atoi(tagArray[1])
+		if err != nil {
+			panic("protobuf tag field not an integer: " + tagArray[1])
+		}
+
+		name := ""
+		for _, tag := range tagArray[3:] {
+			if strings.HasPrefix(tag, "name=") {
+				name = tag[5:]
+			}
+		}
+
+		// Extract unmarshaling function from the field (its type and tags).
+		unmarshal := fieldUnmarshaler(&f)
+
+		// Required field?
+		var reqMask uint64
+		if tagArray[2] == "req" {
+			bit := len(u.reqFields)
+			u.reqFields = append(u.reqFields, name)
+			reqMask = uint64(1) << uint(bit)
+			// TODO: if we have more than 64 required fields, we end up
+			// not verifying that all required fields are present.
+			// Fix this, perhaps using a count of required fields?
+		}
+
+		// Store the info in the correct slot in the message.
+		u.setTag(tag, toField(&f), unmarshal, reqMask, name)
+	}
+
+	// Find any types associated with oneof fields.
+	var oneofImplementers []interface{}
+	switch m := reflect.Zero(reflect.PtrTo(t)).Interface().(type) {
+	case oneofFuncsIface:
+		_, _, _, oneofImplementers = m.XXX_OneofFuncs()
+	case oneofWrappersIface:
+		oneofImplementers = m.XXX_OneofWrappers()
+	}
+	for _, v := range oneofImplementers {
+		tptr := reflect.TypeOf(v) // *Msg_X
+		typ := tptr.Elem()        // Msg_X
+
+		f := typ.Field(0) // oneof implementers have one field
+		baseUnmarshal := fieldUnmarshaler(&f)
+		tags := strings.Split(f.Tag.Get("protobuf"), ",")
+		fieldNum, err := strconv.Atoi(tags[1])
+		if err != nil {
+			panic("protobuf tag field not an integer: " + tags[1])
+		}
+		var name string
+		for _, tag := range tags {
+			if strings.HasPrefix(tag, "name=") {
+				name = strings.TrimPrefix(tag, "name=")
+				break
+			}
+		}
+
+		// Find the oneof field that this struct implements.
+		// Might take O(n^2) to process all of the oneofs, but who cares.
+		for _, of := range oneofFields {
+			if tptr.Implements(of.ityp) {
+				// We have found the corresponding interface for this struct.
+				// That lets us know where this struct should be stored
+				// when we encounter it during unmarshaling.
+				unmarshal := makeUnmarshalOneof(typ, of.ityp, baseUnmarshal)
+				u.setTag(fieldNum, of.field, unmarshal, 0, name)
+			}
+		}
+
+	}
+
+	// Get extension ranges, if any.
+	fn := reflect.Zero(reflect.PtrTo(t)).MethodByName("ExtensionRangeArray")
+	if fn.IsValid() {
+		if !u.extensions.IsValid() && !u.oldExtensions.IsValid() {
+			panic("a message with extensions, but no extensions field in " + t.Name())
+		}
+		u.extensionRanges = fn.Call(nil)[0].Interface().([]ExtensionRange)
+	}
+
+	// Explicitly disallow tag 0. This will ensure we flag an error
+	// when decoding a buffer of all zeros. Without this code, we
+	// would decode and skip an all-zero buffer of even length.
+	// [0 0] is [tag=0/wiretype=varint varint-encoded-0].
+	u.setTag(0, zeroField, func(b []byte, f pointer, w int) ([]byte, error) {
+		return nil, fmt.Errorf("proto: %s: illegal tag 0 (wire type %d)", t, w)
+	}, 0, "")
+
+	// Set mask for required field check.
+	u.reqMask = uint64(1)<<uint(len(u.reqFields)) - 1
+
+	atomic.StoreInt32(&u.initialized, 1)
+}
+
+// setTag stores the unmarshal information for the given tag.
+// tag = tag # for field
+// field/unmarshal = unmarshal info for that field.
+// reqMask = if required, bitmask for field position in required field list. 0 otherwise.
+// name = short name of the field.
+func (u *unmarshalInfo) setTag(tag int, field field, unmarshal unmarshaler, reqMask uint64, name string) {
+	i := unmarshalFieldInfo{field: field, unmarshal: unmarshal, reqMask: reqMask, name: name}
+	n := u.typ.NumField()
+	if tag >= 0 && (tag < 16 || tag < 2*n) { // TODO: what are the right numbers here?
+		for len(u.dense) <= tag {
+			u.dense = append(u.dense, unmarshalFieldInfo{})
+		}
+		u.dense[tag] = i
+		return
+	}
+	if u.sparse == nil {
+		u.sparse = map[uint64]unmarshalFieldInfo{}
+	}
+	u.sparse[uint64(tag)] = i
+}
+
+// fieldUnmarshaler returns an unmarshaler for the given field.
+func fieldUnmarshaler(f *reflect.StructField) unmarshaler {
+	if f.Type.Kind() == reflect.Map {
+		return makeUnmarshalMap(f)
+	}
+	return typeUnmarshaler(f.Type, f.Tag.Get("protobuf"))
+}
+
+// typeUnmarshaler returns an unmarshaler for the given field type / field tag pair.
+func typeUnmarshaler(t reflect.Type, tags string) unmarshaler {
+	tagArray := strings.Split(tags, ",")
+	encoding := tagArray[0]
+	name := "unknown"
+	proto3 := false
+	validateUTF8 := true
+	for _, tag := range tagArray[3:] {
+		if strings.HasPrefix(tag, "name=") {
+			name = tag[5:]
+		}
+		if tag == "proto3" {
+			proto3 = true
+		}
+	}
+	validateUTF8 = validateUTF8 && proto3
+
+	// Figure out packaging (pointer, slice, or both)
+	slice := false
+	pointer := false
+	if t.Kind() == reflect.Slice && t.Elem().Kind() != reflect.Uint8 {
+		slice = true
+		t = t.Elem()
+	}
+	if t.Kind() == reflect.Ptr {
+		pointer = true
+		t = t.Elem()
+	}
+
+	// We'll never have both pointer and slice for basic types.
+	if pointer && slice && t.Kind() != reflect.Struct {
+		panic("both pointer and slice for basic type in " + t.Name())
+	}
+
+	switch t.Kind() {
+	case reflect.Bool:
+		if pointer {
+			return unmarshalBoolPtr
+		}
+		if slice {
+			return unmarshalBoolSlice
+		}
+		return unmarshalBoolValue
+	case reflect.Int32:
+		switch encoding {
+		case "fixed32":
+			if pointer {
+				return unmarshalFixedS32Ptr
+			}
+			if slice {
+				return unmarshalFixedS32Slice
+			}
+			return unmarshalFixedS32Value
+		case "varint":
+			// this could be int32 or enum
+			if pointer {
+				return unmarshalInt32Ptr
+			}
+			if slice {
+				return unmarshalInt32Slice
+			}
+			return unmarshalInt32Value
+		case "zigzag32":
+			if pointer {
+				return unmarshalSint32Ptr
+			}
+			if slice {
+				return unmarshalSint32Slice
+			}
+			return unmarshalSint32Value
+		}
+	case reflect.Int64:
+		switch encoding {
+		case "fixed64":
+			if pointer {
+				return unmarshalFixedS64Ptr
+			}
+			if slice {
+				return unmarshalFixedS64Slice
+			}
+			return unmarshalFixedS64Value
+		case "varint":
+			if pointer {
+				return unmarshalInt64Ptr
+			}
+			if slice {
+				return unmarshalInt64Slice
+			}
+			return unmarshalInt64Value
+		case "zigzag64":
+			if pointer {
+				return unmarshalSint64Ptr
+			}
+			if slice {
+				return unmarshalSint64Slice
+			}
+			return unmarshalSint64Value
+		}
+	case reflect.Uint32:
+		switch encoding {
+		case "fixed32":
+			if pointer {
+				return unmarshalFixed32Ptr
+			}
+			if slice {
+				return unmarshalFixed32Slice
+			}
+			return unmarshalFixed32Value
+		case "varint":
+			if pointer {
+				return unmarshalUint32Ptr
+			}
+			if slice {
+				return unmarshalUint32Slice
+			}
+			return unmarshalUint32Value
+		}
+	case reflect.Uint64:
+		switch encoding {
+		case "fixed64":
+			if pointer {
+				return unmarshalFixed64Ptr
+			}
+			if slice {
+				return unmarshalFixed64Slice
+			}
+			return unmarshalFixed64Value
+		case "varint":
+			if pointer {
+				return unmarshalUint64Ptr
+			}
+			if slice {
+				return unmarshalUint64Slice
+			}
+			return unmarshalUint64Value
+		}
+	case reflect.Float32:
+		if pointer {
+			return unmarshalFloat32Ptr
+		}
+		if slice {
+			return unmarshalFloat32Slice
+		}
+		return unmarshalFloat32Value
+	case reflect.Float64:
+		if pointer {
+			return unmarshalFloat64Ptr
+		}
+		if slice {
+			return unmarshalFloat64Slice
+		}
+		return unmarshalFloat64Value
+	case reflect.Map:
+		panic("map type in typeUnmarshaler in " + t.Name())
+	case reflect.Slice:
+		if pointer {
+			panic("bad pointer in slice case in " + t.Name())
+		}
+		if slice {
+			return unmarshalBytesSlice
+		}
+		return unmarshalBytesValue
+	case reflect.String:
+		if validateUTF8 {
+			if pointer {
+				return unmarshalUTF8StringPtr
+			}
+			if slice {
+				return unmarshalUTF8StringSlice
+			}
+			return unmarshalUTF8StringValue
+		}
+		if pointer {
+			return unmarshalStringPtr
+		}
+		if slice {
+			return unmarshalStringSlice
+		}
+		return unmarshalStringValue
+	case reflect.Struct:
+		// message or group field
+		if !pointer {
+			panic(fmt.Sprintf("message/group field %s:%s without pointer", t, encoding))
+		}
+		switch encoding {
+		case "bytes":
+			if slice {
+				return makeUnmarshalMessageSlicePtr(getUnmarshalInfo(t), name)
+			}
+			return makeUnmarshalMessagePtr(getUnmarshalInfo(t), name)
+		case "group":
+			if slice {
+				return makeUnmarshalGroupSlicePtr(getUnmarshalInfo(t), name)
+			}
+			return makeUnmarshalGroupPtr(getUnmarshalInfo(t), name)
+		}
+	}
+	panic(fmt.Sprintf("unmarshaler not found type:%s encoding:%s", t, encoding))
+}
+
+// Below are all the unmarshalers for individual fields of various types.
+
+func unmarshalInt64Value(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := int64(x)
+	*f.toInt64() = v
+	return b, nil
+}
+
+func unmarshalInt64Ptr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := int64(x)
+	*f.toInt64Ptr() = &v
+	return b, nil
+}
+
+func unmarshalInt64Slice(b []byte, f pointer, w int) ([]byte, error) {
+	if w == WireBytes { // packed
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		res := b[x:]
+		b = b[:x]
+		for len(b) > 0 {
+			x, n = decodeVarint(b)
+			if n == 0 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			b = b[n:]
+			v := int64(x)
+			s := f.toInt64Slice()
+			*s = append(*s, v)
+		}
+		return res, nil
+	}
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := int64(x)
+	s := f.toInt64Slice()
+	*s = append(*s, v)
+	return b, nil
+}
+
+func unmarshalSint64Value(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := int64(x>>1) ^ int64(x)<<63>>63
+	*f.toInt64() = v
+	return b, nil
+}
+
+func unmarshalSint64Ptr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := int64(x>>1) ^ int64(x)<<63>>63
+	*f.toInt64Ptr() = &v
+	return b, nil
+}
+
+func unmarshalSint64Slice(b []byte, f pointer, w int) ([]byte, error) {
+	if w == WireBytes { // packed
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		res := b[x:]
+		b = b[:x]
+		for len(b) > 0 {
+			x, n = decodeVarint(b)
+			if n == 0 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			b = b[n:]
+			v := int64(x>>1) ^ int64(x)<<63>>63
+			s := f.toInt64Slice()
+			*s = append(*s, v)
+		}
+		return res, nil
+	}
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := int64(x>>1) ^ int64(x)<<63>>63
+	s := f.toInt64Slice()
+	*s = append(*s, v)
+	return b, nil
+}
+
+func unmarshalUint64Value(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := uint64(x)
+	*f.toUint64() = v
+	return b, nil
+}
+
+func unmarshalUint64Ptr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := uint64(x)
+	*f.toUint64Ptr() = &v
+	return b, nil
+}
+
+func unmarshalUint64Slice(b []byte, f pointer, w int) ([]byte, error) {
+	if w == WireBytes { // packed
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		res := b[x:]
+		b = b[:x]
+		for len(b) > 0 {
+			x, n = decodeVarint(b)
+			if n == 0 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			b = b[n:]
+			v := uint64(x)
+			s := f.toUint64Slice()
+			*s = append(*s, v)
+		}
+		return res, nil
+	}
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := uint64(x)
+	s := f.toUint64Slice()
+	*s = append(*s, v)
+	return b, nil
+}
+
+func unmarshalInt32Value(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := int32(x)
+	*f.toInt32() = v
+	return b, nil
+}
+
+func unmarshalInt32Ptr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := int32(x)
+	f.setInt32Ptr(v)
+	return b, nil
+}
+
+func unmarshalInt32Slice(b []byte, f pointer, w int) ([]byte, error) {
+	if w == WireBytes { // packed
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		res := b[x:]
+		b = b[:x]
+		for len(b) > 0 {
+			x, n = decodeVarint(b)
+			if n == 0 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			b = b[n:]
+			v := int32(x)
+			f.appendInt32Slice(v)
+		}
+		return res, nil
+	}
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := int32(x)
+	f.appendInt32Slice(v)
+	return b, nil
+}
+
+func unmarshalSint32Value(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := int32(x>>1) ^ int32(x)<<31>>31
+	*f.toInt32() = v
+	return b, nil
+}
+
+func unmarshalSint32Ptr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := int32(x>>1) ^ int32(x)<<31>>31
+	f.setInt32Ptr(v)
+	return b, nil
+}
+
+func unmarshalSint32Slice(b []byte, f pointer, w int) ([]byte, error) {
+	if w == WireBytes { // packed
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		res := b[x:]
+		b = b[:x]
+		for len(b) > 0 {
+			x, n = decodeVarint(b)
+			if n == 0 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			b = b[n:]
+			v := int32(x>>1) ^ int32(x)<<31>>31
+			f.appendInt32Slice(v)
+		}
+		return res, nil
+	}
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := int32(x>>1) ^ int32(x)<<31>>31
+	f.appendInt32Slice(v)
+	return b, nil
+}
+
+func unmarshalUint32Value(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := uint32(x)
+	*f.toUint32() = v
+	return b, nil
+}
+
+func unmarshalUint32Ptr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := uint32(x)
+	*f.toUint32Ptr() = &v
+	return b, nil
+}
+
+func unmarshalUint32Slice(b []byte, f pointer, w int) ([]byte, error) {
+	if w == WireBytes { // packed
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		res := b[x:]
+		b = b[:x]
+		for len(b) > 0 {
+			x, n = decodeVarint(b)
+			if n == 0 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			b = b[n:]
+			v := uint32(x)
+			s := f.toUint32Slice()
+			*s = append(*s, v)
+		}
+		return res, nil
+	}
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	v := uint32(x)
+	s := f.toUint32Slice()
+	*s = append(*s, v)
+	return b, nil
+}
+
+func unmarshalFixed64Value(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireFixed64 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 8 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
+	*f.toUint64() = v
+	return b[8:], nil
+}
+
+func unmarshalFixed64Ptr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireFixed64 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 8 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
+	*f.toUint64Ptr() = &v
+	return b[8:], nil
+}
+
+func unmarshalFixed64Slice(b []byte, f pointer, w int) ([]byte, error) {
+	if w == WireBytes { // packed
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		res := b[x:]
+		b = b[:x]
+		for len(b) > 0 {
+			if len(b) < 8 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			v := uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
+			s := f.toUint64Slice()
+			*s = append(*s, v)
+			b = b[8:]
+		}
+		return res, nil
+	}
+	if w != WireFixed64 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 8 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
+	s := f.toUint64Slice()
+	*s = append(*s, v)
+	return b[8:], nil
+}
+
+func unmarshalFixedS64Value(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireFixed64 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 8 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := int64(b[0]) | int64(b[1])<<8 | int64(b[2])<<16 | int64(b[3])<<24 | int64(b[4])<<32 | int64(b[5])<<40 | int64(b[6])<<48 | int64(b[7])<<56
+	*f.toInt64() = v
+	return b[8:], nil
+}
+
+func unmarshalFixedS64Ptr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireFixed64 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 8 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := int64(b[0]) | int64(b[1])<<8 | int64(b[2])<<16 | int64(b[3])<<24 | int64(b[4])<<32 | int64(b[5])<<40 | int64(b[6])<<48 | int64(b[7])<<56
+	*f.toInt64Ptr() = &v
+	return b[8:], nil
+}
+
+func unmarshalFixedS64Slice(b []byte, f pointer, w int) ([]byte, error) {
+	if w == WireBytes { // packed
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		res := b[x:]
+		b = b[:x]
+		for len(b) > 0 {
+			if len(b) < 8 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			v := int64(b[0]) | int64(b[1])<<8 | int64(b[2])<<16 | int64(b[3])<<24 | int64(b[4])<<32 | int64(b[5])<<40 | int64(b[6])<<48 | int64(b[7])<<56
+			s := f.toInt64Slice()
+			*s = append(*s, v)
+			b = b[8:]
+		}
+		return res, nil
+	}
+	if w != WireFixed64 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 8 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := int64(b[0]) | int64(b[1])<<8 | int64(b[2])<<16 | int64(b[3])<<24 | int64(b[4])<<32 | int64(b[5])<<40 | int64(b[6])<<48 | int64(b[7])<<56
+	s := f.toInt64Slice()
+	*s = append(*s, v)
+	return b[8:], nil
+}
+
+func unmarshalFixed32Value(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireFixed32 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 4 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
+	*f.toUint32() = v
+	return b[4:], nil
+}
+
+func unmarshalFixed32Ptr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireFixed32 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 4 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
+	*f.toUint32Ptr() = &v
+	return b[4:], nil
+}
+
+func unmarshalFixed32Slice(b []byte, f pointer, w int) ([]byte, error) {
+	if w == WireBytes { // packed
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		res := b[x:]
+		b = b[:x]
+		for len(b) > 0 {
+			if len(b) < 4 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			v := uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
+			s := f.toUint32Slice()
+			*s = append(*s, v)
+			b = b[4:]
+		}
+		return res, nil
+	}
+	if w != WireFixed32 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 4 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
+	s := f.toUint32Slice()
+	*s = append(*s, v)
+	return b[4:], nil
+}
+
+func unmarshalFixedS32Value(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireFixed32 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 4 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := int32(b[0]) | int32(b[1])<<8 | int32(b[2])<<16 | int32(b[3])<<24
+	*f.toInt32() = v
+	return b[4:], nil
+}
+
+func unmarshalFixedS32Ptr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireFixed32 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 4 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := int32(b[0]) | int32(b[1])<<8 | int32(b[2])<<16 | int32(b[3])<<24
+	f.setInt32Ptr(v)
+	return b[4:], nil
+}
+
+func unmarshalFixedS32Slice(b []byte, f pointer, w int) ([]byte, error) {
+	if w == WireBytes { // packed
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		res := b[x:]
+		b = b[:x]
+		for len(b) > 0 {
+			if len(b) < 4 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			v := int32(b[0]) | int32(b[1])<<8 | int32(b[2])<<16 | int32(b[3])<<24
+			f.appendInt32Slice(v)
+			b = b[4:]
+		}
+		return res, nil
+	}
+	if w != WireFixed32 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 4 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := int32(b[0]) | int32(b[1])<<8 | int32(b[2])<<16 | int32(b[3])<<24
+	f.appendInt32Slice(v)
+	return b[4:], nil
+}
+
+func unmarshalBoolValue(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	// Note: any length varint is allowed, even though any sane
+	// encoder will use one byte.
+	// See https://github.com/golang/protobuf/issues/76
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	// TODO: check if x>1? Tests seem to indicate no.
+	v := x != 0
+	*f.toBool() = v
+	return b[n:], nil
+}
+
+func unmarshalBoolPtr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := x != 0
+	*f.toBoolPtr() = &v
+	return b[n:], nil
+}
+
+func unmarshalBoolSlice(b []byte, f pointer, w int) ([]byte, error) {
+	if w == WireBytes { // packed
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		res := b[x:]
+		b = b[:x]
+		for len(b) > 0 {
+			x, n = decodeVarint(b)
+			if n == 0 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			v := x != 0
+			s := f.toBoolSlice()
+			*s = append(*s, v)
+			b = b[n:]
+		}
+		return res, nil
+	}
+	if w != WireVarint {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := x != 0
+	s := f.toBoolSlice()
+	*s = append(*s, v)
+	return b[n:], nil
+}
+
+func unmarshalFloat64Value(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireFixed64 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 8 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := math.Float64frombits(uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56)
+	*f.toFloat64() = v
+	return b[8:], nil
+}
+
+func unmarshalFloat64Ptr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireFixed64 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 8 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := math.Float64frombits(uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56)
+	*f.toFloat64Ptr() = &v
+	return b[8:], nil
+}
+
+func unmarshalFloat64Slice(b []byte, f pointer, w int) ([]byte, error) {
+	if w == WireBytes { // packed
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		res := b[x:]
+		b = b[:x]
+		for len(b) > 0 {
+			if len(b) < 8 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			v := math.Float64frombits(uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56)
+			s := f.toFloat64Slice()
+			*s = append(*s, v)
+			b = b[8:]
+		}
+		return res, nil
+	}
+	if w != WireFixed64 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 8 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := math.Float64frombits(uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56)
+	s := f.toFloat64Slice()
+	*s = append(*s, v)
+	return b[8:], nil
+}
+
+func unmarshalFloat32Value(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireFixed32 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 4 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := math.Float32frombits(uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24)
+	*f.toFloat32() = v
+	return b[4:], nil
+}
+
+func unmarshalFloat32Ptr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireFixed32 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 4 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := math.Float32frombits(uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24)
+	*f.toFloat32Ptr() = &v
+	return b[4:], nil
+}
+
+func unmarshalFloat32Slice(b []byte, f pointer, w int) ([]byte, error) {
+	if w == WireBytes { // packed
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		res := b[x:]
+		b = b[:x]
+		for len(b) > 0 {
+			if len(b) < 4 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			v := math.Float32frombits(uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24)
+			s := f.toFloat32Slice()
+			*s = append(*s, v)
+			b = b[4:]
+		}
+		return res, nil
+	}
+	if w != WireFixed32 {
+		return b, errInternalBadWireType
+	}
+	if len(b) < 4 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := math.Float32frombits(uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24)
+	s := f.toFloat32Slice()
+	*s = append(*s, v)
+	return b[4:], nil
+}
+
+func unmarshalStringValue(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireBytes {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	if x > uint64(len(b)) {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := string(b[:x])
+	*f.toString() = v
+	return b[x:], nil
+}
+
+func unmarshalStringPtr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireBytes {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	if x > uint64(len(b)) {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := string(b[:x])
+	*f.toStringPtr() = &v
+	return b[x:], nil
+}
+
+func unmarshalStringSlice(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireBytes {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	if x > uint64(len(b)) {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := string(b[:x])
+	s := f.toStringSlice()
+	*s = append(*s, v)
+	return b[x:], nil
+}
+
+func unmarshalUTF8StringValue(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireBytes {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	if x > uint64(len(b)) {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := string(b[:x])
+	*f.toString() = v
+	if !utf8.ValidString(v) {
+		return b[x:], errInvalidUTF8
+	}
+	return b[x:], nil
+}
+
+func unmarshalUTF8StringPtr(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireBytes {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	if x > uint64(len(b)) {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := string(b[:x])
+	*f.toStringPtr() = &v
+	if !utf8.ValidString(v) {
+		return b[x:], errInvalidUTF8
+	}
+	return b[x:], nil
+}
+
+func unmarshalUTF8StringSlice(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireBytes {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	if x > uint64(len(b)) {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := string(b[:x])
+	s := f.toStringSlice()
+	*s = append(*s, v)
+	if !utf8.ValidString(v) {
+		return b[x:], errInvalidUTF8
+	}
+	return b[x:], nil
+}
+
+var emptyBuf [0]byte
+
+func unmarshalBytesValue(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireBytes {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	if x > uint64(len(b)) {
+		return nil, io.ErrUnexpectedEOF
+	}
+	// The use of append here is a trick which avoids the zeroing
+	// that would be required if we used a make/copy pair.
+	// We append to emptyBuf instead of nil because we want
+	// a non-nil result even when the length is 0.
+	v := append(emptyBuf[:], b[:x]...)
+	*f.toBytes() = v
+	return b[x:], nil
+}
+
+func unmarshalBytesSlice(b []byte, f pointer, w int) ([]byte, error) {
+	if w != WireBytes {
+		return b, errInternalBadWireType
+	}
+	x, n := decodeVarint(b)
+	if n == 0 {
+		return nil, io.ErrUnexpectedEOF
+	}
+	b = b[n:]
+	if x > uint64(len(b)) {
+		return nil, io.ErrUnexpectedEOF
+	}
+	v := append(emptyBuf[:], b[:x]...)
+	s := f.toBytesSlice()
+	*s = append(*s, v)
+	return b[x:], nil
+}
+
+func makeUnmarshalMessagePtr(sub *unmarshalInfo, name string) unmarshaler {
+	return func(b []byte, f pointer, w int) ([]byte, error) {
+		if w != WireBytes {
+			return b, errInternalBadWireType
+		}
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		// First read the message field to see if something is there.
+		// The semantics of multiple submessages are weird.  Instead of
+		// the last one winning (as it is for all other fields), multiple
+		// submessages are merged.
+		v := f.getPointer()
+		if v.isNil() {
+			v = valToPointer(reflect.New(sub.typ))
+			f.setPointer(v)
+		}
+		err := sub.unmarshal(v, b[:x])
+		if err != nil {
+			if r, ok := err.(*RequiredNotSetError); ok {
+				r.field = name + "." + r.field
+			} else {
+				return nil, err
+			}
+		}
+		return b[x:], err
+	}
+}
+
+func makeUnmarshalMessageSlicePtr(sub *unmarshalInfo, name string) unmarshaler {
+	return func(b []byte, f pointer, w int) ([]byte, error) {
+		if w != WireBytes {
+			return b, errInternalBadWireType
+		}
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		v := valToPointer(reflect.New(sub.typ))
+		err := sub.unmarshal(v, b[:x])
+		if err != nil {
+			if r, ok := err.(*RequiredNotSetError); ok {
+				r.field = name + "." + r.field
+			} else {
+				return nil, err
+			}
+		}
+		f.appendPointer(v)
+		return b[x:], err
+	}
+}
+
+func makeUnmarshalGroupPtr(sub *unmarshalInfo, name string) unmarshaler {
+	return func(b []byte, f pointer, w int) ([]byte, error) {
+		if w != WireStartGroup {
+			return b, errInternalBadWireType
+		}
+		x, y := findEndGroup(b)
+		if x < 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		v := f.getPointer()
+		if v.isNil() {
+			v = valToPointer(reflect.New(sub.typ))
+			f.setPointer(v)
+		}
+		err := sub.unmarshal(v, b[:x])
+		if err != nil {
+			if r, ok := err.(*RequiredNotSetError); ok {
+				r.field = name + "." + r.field
+			} else {
+				return nil, err
+			}
+		}
+		return b[y:], err
+	}
+}
+
+func makeUnmarshalGroupSlicePtr(sub *unmarshalInfo, name string) unmarshaler {
+	return func(b []byte, f pointer, w int) ([]byte, error) {
+		if w != WireStartGroup {
+			return b, errInternalBadWireType
+		}
+		x, y := findEndGroup(b)
+		if x < 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		v := valToPointer(reflect.New(sub.typ))
+		err := sub.unmarshal(v, b[:x])
+		if err != nil {
+			if r, ok := err.(*RequiredNotSetError); ok {
+				r.field = name + "." + r.field
+			} else {
+				return nil, err
+			}
+		}
+		f.appendPointer(v)
+		return b[y:], err
+	}
+}
+
+func makeUnmarshalMap(f *reflect.StructField) unmarshaler {
+	t := f.Type
+	kt := t.Key()
+	vt := t.Elem()
+	unmarshalKey := typeUnmarshaler(kt, f.Tag.Get("protobuf_key"))
+	unmarshalVal := typeUnmarshaler(vt, f.Tag.Get("protobuf_val"))
+	return func(b []byte, f pointer, w int) ([]byte, error) {
+		// The map entry is a submessage. Figure out how big it is.
+		if w != WireBytes {
+			return nil, fmt.Errorf("proto: bad wiretype for map field: got %d want %d", w, WireBytes)
+		}
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		if x > uint64(len(b)) {
+			return nil, io.ErrUnexpectedEOF
+		}
+		r := b[x:] // unused data to return
+		b = b[:x]  // data for map entry
+
+		// Note: we could use #keys * #values ~= 200 functions
+		// to do map decoding without reflection. Probably not worth it.
+		// Maps will be somewhat slow. Oh well.
+
+		// Read key and value from data.
+		var nerr nonFatal
+		k := reflect.New(kt)
+		v := reflect.New(vt)
+		for len(b) > 0 {
+			x, n := decodeVarint(b)
+			if n == 0 {
+				return nil, io.ErrUnexpectedEOF
+			}
+			wire := int(x) & 7
+			b = b[n:]
+
+			var err error
+			switch x >> 3 {
+			case 1:
+				b, err = unmarshalKey(b, valToPointer(k), wire)
+			case 2:
+				b, err = unmarshalVal(b, valToPointer(v), wire)
+			default:
+				err = errInternalBadWireType // skip unknown tag
+			}
+
+			if nerr.Merge(err) {
+				continue
+			}
+			if err != errInternalBadWireType {
+				return nil, err
+			}
+
+			// Skip past unknown fields.
+			b, err = skipField(b, wire)
+			if err != nil {
+				return nil, err
+			}
+		}
+
+		// Get map, allocate if needed.
+		m := f.asPointerTo(t).Elem() // an addressable map[K]T
+		if m.IsNil() {
+			m.Set(reflect.MakeMap(t))
+		}
+
+		// Insert into map.
+		m.SetMapIndex(k.Elem(), v.Elem())
+
+		return r, nerr.E
+	}
+}
+
+// makeUnmarshalOneof makes an unmarshaler for oneof fields.
+// for:
+// message Msg {
+//   oneof F {
+//     int64 X = 1;
+//     float64 Y = 2;
+//   }
+// }
+// typ is the type of the concrete entry for a oneof case (e.g. Msg_X).
+// ityp is the interface type of the oneof field (e.g. isMsg_F).
+// unmarshal is the unmarshaler for the base type of the oneof case (e.g. int64).
+// Note that this function will be called once for each case in the oneof.
+func makeUnmarshalOneof(typ, ityp reflect.Type, unmarshal unmarshaler) unmarshaler {
+	sf := typ.Field(0)
+	field0 := toField(&sf)
+	return func(b []byte, f pointer, w int) ([]byte, error) {
+		// Allocate holder for value.
+		v := reflect.New(typ)
+
+		// Unmarshal data into holder.
+		// We unmarshal into the first field of the holder object.
+		var err error
+		var nerr nonFatal
+		b, err = unmarshal(b, valToPointer(v).offset(field0), w)
+		if !nerr.Merge(err) {
+			return nil, err
+		}
+
+		// Write pointer to holder into target field.
+		f.asPointerTo(ityp).Elem().Set(v)
+
+		return b, nerr.E
+	}
+}
+
+// Error used by decode internally.
+var errInternalBadWireType = errors.New("proto: internal error: bad wiretype")
+
+// skipField skips past a field of type wire and returns the remaining bytes.
+func skipField(b []byte, wire int) ([]byte, error) {
+	switch wire {
+	case WireVarint:
+		_, k := decodeVarint(b)
+		if k == 0 {
+			return b, io.ErrUnexpectedEOF
+		}
+		b = b[k:]
+	case WireFixed32:
+		if len(b) < 4 {
+			return b, io.ErrUnexpectedEOF
+		}
+		b = b[4:]
+	case WireFixed64:
+		if len(b) < 8 {
+			return b, io.ErrUnexpectedEOF
+		}
+		b = b[8:]
+	case WireBytes:
+		m, k := decodeVarint(b)
+		if k == 0 || uint64(len(b)-k) < m {
+			return b, io.ErrUnexpectedEOF
+		}
+		b = b[uint64(k)+m:]
+	case WireStartGroup:
+		_, i := findEndGroup(b)
+		if i == -1 {
+			return b, io.ErrUnexpectedEOF
+		}
+		b = b[i:]
+	default:
+		return b, fmt.Errorf("proto: can't skip unknown wire type %d", wire)
+	}
+	return b, nil
+}
+
+// findEndGroup finds the index of the next EndGroup tag.
+// Groups may be nested, so the "next" EndGroup tag is the first
+// unpaired EndGroup.
+// findEndGroup returns the indexes of the start and end of the EndGroup tag.
+// Returns (-1,-1) if it can't find one.
+func findEndGroup(b []byte) (int, int) {
+	depth := 1
+	i := 0
+	for {
+		x, n := decodeVarint(b[i:])
+		if n == 0 {
+			return -1, -1
+		}
+		j := i
+		i += n
+		switch x & 7 {
+		case WireVarint:
+			_, k := decodeVarint(b[i:])
+			if k == 0 {
+				return -1, -1
+			}
+			i += k
+		case WireFixed32:
+			if len(b)-4 < i {
+				return -1, -1
+			}
+			i += 4
+		case WireFixed64:
+			if len(b)-8 < i {
+				return -1, -1
+			}
+			i += 8
+		case WireBytes:
+			m, k := decodeVarint(b[i:])
+			if k == 0 {
+				return -1, -1
+			}
+			i += k
+			if uint64(len(b)-i) < m {
+				return -1, -1
+			}
+			i += int(m)
+		case WireStartGroup:
+			depth++
+		case WireEndGroup:
+			depth--
+			if depth == 0 {
+				return j, i
+			}
+		default:
+			return -1, -1
+		}
+	}
+}
+
+// encodeVarint appends a varint-encoded integer to b and returns the result.
+func encodeVarint(b []byte, x uint64) []byte {
+	for x >= 1<<7 {
+		b = append(b, byte(x&0x7f|0x80))
+		x >>= 7
+	}
+	return append(b, byte(x))
+}
+
+// decodeVarint reads a varint-encoded integer from b.
+// Returns the decoded integer and the number of bytes read.
+// If there is an error, it returns 0,0.
+func decodeVarint(b []byte) (uint64, int) {
+	var x, y uint64
+	if len(b) == 0 {
+		goto bad
+	}
+	x = uint64(b[0])
+	if x < 0x80 {
+		return x, 1
+	}
+	x -= 0x80
+
+	if len(b) <= 1 {
+		goto bad
+	}
+	y = uint64(b[1])
+	x += y << 7
+	if y < 0x80 {
+		return x, 2
+	}
+	x -= 0x80 << 7
+
+	if len(b) <= 2 {
+		goto bad
+	}
+	y = uint64(b[2])
+	x += y << 14
+	if y < 0x80 {
+		return x, 3
+	}
+	x -= 0x80 << 14
+
+	if len(b) <= 3 {
+		goto bad
+	}
+	y = uint64(b[3])
+	x += y << 21
+	if y < 0x80 {
+		return x, 4
+	}
+	x -= 0x80 << 21
+
+	if len(b) <= 4 {
+		goto bad
+	}
+	y = uint64(b[4])
+	x += y << 28
+	if y < 0x80 {
+		return x, 5
+	}
+	x -= 0x80 << 28
+
+	if len(b) <= 5 {
+		goto bad
+	}
+	y = uint64(b[5])
+	x += y << 35
+	if y < 0x80 {
+		return x, 6
+	}
+	x -= 0x80 << 35
+
+	if len(b) <= 6 {
+		goto bad
+	}
+	y = uint64(b[6])
+	x += y << 42
+	if y < 0x80 {
+		return x, 7
+	}
+	x -= 0x80 << 42
+
+	if len(b) <= 7 {
+		goto bad
+	}
+	y = uint64(b[7])
+	x += y << 49
+	if y < 0x80 {
+		return x, 8
+	}
+	x -= 0x80 << 49
+
+	if len(b) <= 8 {
+		goto bad
+	}
+	y = uint64(b[8])
+	x += y << 56
+	if y < 0x80 {
+		return x, 9
+	}
+	x -= 0x80 << 56
+
+	if len(b) <= 9 {
+		goto bad
+	}
+	y = uint64(b[9])
+	x += y << 63
+	if y < 2 {
+		return x, 10
+	}
+
+bad:
+	return 0, 0
+}