Update module lib/pq to v1.6.0 (#572)

Update module lib/pq to v1.6.0

Reviewed-on: https://kolaente.dev/vikunja/api/pulls/572

vendor/github.com/jcmturner/rpc/v2/ndr/arrays.go

@@ -0,0 +1,413 @@
+package ndr
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"strconv"
+)
+
+// intFromTag returns an int that is a value in a struct tag key/value pair
+func intFromTag(tag reflect.StructTag, key string) (int, error) {
+	ndrTag := parseTags(tag)
+	d := 1
+	if n, ok := ndrTag.Map[key]; ok {
+		i, err := strconv.Atoi(n)
+		if err != nil {
+			return d, fmt.Errorf("invalid dimensions tag [%s]: %v", n, err)
+		}
+		d = i
+	}
+	return d, nil
+}
+
+// parseDimensions returns the a slice of the size of each dimension and type of the member at the deepest level.
+func parseDimensions(v reflect.Value) (l []int, tb reflect.Type) {
+	if v.Kind() == reflect.Ptr {
+		v = v.Elem()
+	}
+	t := v.Type()
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+	if t.Kind() != reflect.Array && t.Kind() != reflect.Slice {
+		return
+	}
+	l = append(l, v.Len())
+	if t.Elem().Kind() == reflect.Array || t.Elem().Kind() == reflect.Slice {
+		// contains array or slice
+		var m []int
+		m, tb = parseDimensions(v.Index(0))
+		l = append(l, m...)
+	} else {
+		tb = t.Elem()
+	}
+	return
+}
+
+// sliceDimensions returns the count of dimensions a slice has.
+func sliceDimensions(t reflect.Type) (d int, tb reflect.Type) {
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+	if t.Kind() == reflect.Slice {
+		d++
+		var n int
+		n, tb = sliceDimensions(t.Elem())
+		d += n
+	} else {
+		tb = t
+	}
+	return
+}
+
+// makeSubSlices is a deep recursive creation/initialisation of multi-dimensional slices.
+// Takes the reflect.Value of the 1st dimension and a slice of the lengths of the sub dimensions
+func makeSubSlices(v reflect.Value, l []int) {
+	ty := v.Type().Elem()
+	if ty.Kind() != reflect.Slice {
+		return
+	}
+	for i := 0; i < v.Len(); i++ {
+		s := reflect.MakeSlice(ty, l[0], l[0])
+		v.Index(i).Set(s)
+		// Are there more sub dimensions?
+		if len(l) > 1 {
+			makeSubSlices(v.Index(i), l[1:])
+		}
+	}
+	return
+}
+
+// multiDimensionalIndexPermutations returns all the permutations of the indexes of a multi-dimensional slice.
+// The input is a slice of integers that indicates the max size/length of each dimension
+func multiDimensionalIndexPermutations(l []int) (ps [][]int) {
+	z := make([]int, len(l), len(l)) // The zeros permutation
+	ps = append(ps, z)
+	// for each dimension, in reverse
+	for i := len(l) - 1; i >= 0; i-- {
+		ws := make([][]int, len(ps))
+		copy(ws, ps)
+		//create a permutation for each of the iterations of the current dimension
+		for j := 1; j <= l[i]-1; j++ {
+			// For each existing permutation
+			for _, p := range ws {
+				np := make([]int, len(p), len(p))
+				copy(np, p)
+				np[i] = j
+				ps = append(ps, np)
+			}
+		}
+	}
+	return
+}
+
+// precedingMax reads off the next conformant max value
+func (dec *Decoder) precedingMax() uint32 {
+	m := dec.conformantMax[0]
+	dec.conformantMax = dec.conformantMax[1:]
+	return m
+}
+
+// fillFixedArray establishes if the fixed array is uni or multi dimensional and then fills it.
+func (dec *Decoder) fillFixedArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error {
+	l, t := parseDimensions(v)
+	if t.Kind() == reflect.String {
+		tag = reflect.StructTag(subStringArrayTag)
+	}
+	if len(l) < 1 {
+		return errors.New("could not establish dimensions of fixed array")
+	}
+	if len(l) == 1 {
+		err := dec.fillUniDimensionalFixedArray(v, tag, def)
+		if err != nil {
+			return fmt.Errorf("could not fill uni-dimensional fixed array: %v", err)
+		}
+		return nil
+	}
+	// Fixed array is multidimensional
+	ps := multiDimensionalIndexPermutations(l[:len(l)-1])
+	for _, p := range ps {
+		// Get current multi-dimensional index to fill
+		a := v
+		for _, i := range p {
+			a = a.Index(i)
+		}
+		// fill with the last dimension array
+		err := dec.fillUniDimensionalFixedArray(a, tag, def)
+		if err != nil {
+			return fmt.Errorf("could not fill dimension %v of multi-dimensional fixed array: %v", p, err)
+		}
+	}
+	return nil
+}
+
+// readUniDimensionalFixedArray reads an array (not slice) from the byte stream.
+func (dec *Decoder) fillUniDimensionalFixedArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error {
+	for i := 0; i < v.Len(); i++ {
+		err := dec.fill(v.Index(i), tag, def)
+		if err != nil {
+			return fmt.Errorf("could not fill index %d of fixed array: %v", i, err)
+		}
+	}
+	return nil
+}
+
+// fillConformantArray establishes if the conformant array is uni or multi dimensional and then fills the slice.
+func (dec *Decoder) fillConformantArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error {
+	d, _ := sliceDimensions(v.Type())
+	if d > 1 {
+		err := dec.fillMultiDimensionalConformantArray(v, d, tag, def)
+		if err != nil {
+			return err
+		}
+	} else {
+		err := dec.fillUniDimensionalConformantArray(v, tag, def)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// fillUniDimensionalConformantArray fills the uni-dimensional slice value.
+func (dec *Decoder) fillUniDimensionalConformantArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error {
+	m := dec.precedingMax()
+	n := int(m)
+	a := reflect.MakeSlice(v.Type(), n, n)
+	for i := 0; i < n; i++ {
+		err := dec.fill(a.Index(i), tag, def)
+		if err != nil {
+			return fmt.Errorf("could not fill index %d of uni-dimensional conformant array: %v", i, err)
+		}
+	}
+	v.Set(a)
+	return nil
+}
+
+// fillMultiDimensionalConformantArray fills the multi-dimensional slice value provided from conformant array data.
+// The number of dimensions must be specified. This must be less than or equal to the dimensions in the slice for this
+// method not to panic.
+func (dec *Decoder) fillMultiDimensionalConformantArray(v reflect.Value, d int, tag reflect.StructTag, def *[]deferedPtr) error {
+	// Read the max size of each dimensions from the ndr stream
+	l := make([]int, d, d)
+	for i := range l {
+		l[i] = int(dec.precedingMax())
+	}
+	// Initialise size of slices
+	//   Initialise the size of the 1st dimension
+	ty := v.Type()
+	v.Set(reflect.MakeSlice(ty, l[0], l[0]))
+	// Initialise the size of the other dimensions recursively
+	makeSubSlices(v, l[1:])
+
+	// Get all permutations of the indexes and go through each and fill
+	ps := multiDimensionalIndexPermutations(l)
+	for _, p := range ps {
+		// Get current multi-dimensional index to fill
+		a := v
+		for _, i := range p {
+			a = a.Index(i)
+		}
+		err := dec.fill(a, tag, def)
+		if err != nil {
+			return fmt.Errorf("could not fill index %v of slice: %v", p, err)
+		}
+	}
+	return nil
+}
+
+// fillVaryingArray establishes if the varying array is uni or multi dimensional and then fills the slice.
+func (dec *Decoder) fillVaryingArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error {
+	d, t := sliceDimensions(v.Type())
+	if d > 1 {
+		err := dec.fillMultiDimensionalVaryingArray(v, t, d, tag, def)
+		if err != nil {
+			return err
+		}
+	} else {
+		err := dec.fillUniDimensionalVaryingArray(v, tag, def)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// fillUniDimensionalVaryingArray fills the uni-dimensional slice value.
+func (dec *Decoder) fillUniDimensionalVaryingArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error {
+	o, err := dec.readUint32()
+	if err != nil {
+		return fmt.Errorf("could not read offset of uni-dimensional varying array: %v", err)
+	}
+	s, err := dec.readUint32()
+	if err != nil {
+		return fmt.Errorf("could not establish actual count of uni-dimensional varying array: %v", err)
+	}
+	t := v.Type()
+	// Total size of the array is the offset in the index being passed plus the actual count of elements being passed.
+	n := int(s + o)
+	a := reflect.MakeSlice(t, n, n)
+	// Populate the array starting at the offset specified
+	for i := int(o); i < n; i++ {
+		err := dec.fill(a.Index(i), tag, def)
+		if err != nil {
+			return fmt.Errorf("could not fill index %d of uni-dimensional varying array: %v", i, err)
+		}
+	}
+	v.Set(a)
+	return nil
+}
+
+// fillMultiDimensionalVaryingArray fills the multi-dimensional slice value provided from varying array data.
+// The number of dimensions must be specified. This must be less than or equal to the dimensions in the slice for this
+// method not to panic.
+func (dec *Decoder) fillMultiDimensionalVaryingArray(v reflect.Value, t reflect.Type, d int, tag reflect.StructTag, def *[]deferedPtr) error {
+	// Read the offset and actual count of each dimensions from the ndr stream
+	o := make([]int, d, d)
+	l := make([]int, d, d)
+	for i := range l {
+		off, err := dec.readUint32()
+		if err != nil {
+			return fmt.Errorf("could not read offset of dimension %d: %v", i+1, err)
+		}
+		o[i] = int(off)
+		s, err := dec.readUint32()
+		if err != nil {
+			return fmt.Errorf("could not read size of dimension %d: %v", i+1, err)
+		}
+		l[i] = int(s) + int(off)
+	}
+	// Initialise size of slices
+	//   Initialise the size of the 1st dimension
+	ty := v.Type()
+	v.Set(reflect.MakeSlice(ty, l[0], l[0]))
+	// Initialise the size of the other dimensions recursively
+	makeSubSlices(v, l[1:])
+
+	// Get all permutations of the indexes and go through each and fill
+	ps := multiDimensionalIndexPermutations(l)
+	for _, p := range ps {
+		// Get current multi-dimensional index to fill
+		a := v
+		var os bool // should this permutation be skipped due to the offset of any of the dimensions?
+		for i, j := range p {
+			if j < o[i] {
+				os = true
+				break
+			}
+			a = a.Index(j)
+		}
+		if os {
+			// This permutation should be skipped as it is less than the offset for one of the dimensions.
+			continue
+		}
+		err := dec.fill(a, tag, def)
+		if err != nil {
+			return fmt.Errorf("could not fill index %v of slice: %v", p, err)
+		}
+	}
+	return nil
+}
+
+// fillConformantVaryingArray establishes if the varying array is uni or multi dimensional and then fills the slice.
+func (dec *Decoder) fillConformantVaryingArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error {
+	d, t := sliceDimensions(v.Type())
+	if d > 1 {
+		err := dec.fillMultiDimensionalConformantVaryingArray(v, t, d, tag, def)
+		if err != nil {
+			return err
+		}
+	} else {
+		err := dec.fillUniDimensionalConformantVaryingArray(v, tag, def)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// fillUniDimensionalConformantVaryingArray fills the uni-dimensional slice value.
+func (dec *Decoder) fillUniDimensionalConformantVaryingArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error {
+	m := dec.precedingMax()
+	o, err := dec.readUint32()
+	if err != nil {
+		return fmt.Errorf("could not read offset of uni-dimensional conformant varying array: %v", err)
+	}
+	s, err := dec.readUint32()
+	if err != nil {
+		return fmt.Errorf("could not establish actual count of uni-dimensional conformant varying array: %v", err)
+	}
+	if m < o+s {
+		return errors.New("max count is less than the offset plus actual count")
+	}
+	t := v.Type()
+	n := int(s)
+	a := reflect.MakeSlice(t, n, n)
+	for i := int(o); i < n; i++ {
+		err := dec.fill(a.Index(i), tag, def)
+		if err != nil {
+			return fmt.Errorf("could not fill index %d of uni-dimensional conformant varying array: %v", i, err)
+		}
+	}
+	v.Set(a)
+	return nil
+}
+
+// fillMultiDimensionalConformantVaryingArray fills the multi-dimensional slice value provided from conformant varying array data.
+// The number of dimensions must be specified. This must be less than or equal to the dimensions in the slice for this
+// method not to panic.
+func (dec *Decoder) fillMultiDimensionalConformantVaryingArray(v reflect.Value, t reflect.Type, d int, tag reflect.StructTag, def *[]deferedPtr) error {
+	// Read the offset and actual count of each dimensions from the ndr stream
+	m := make([]int, d, d)
+	for i := range m {
+		m[i] = int(dec.precedingMax())
+	}
+	o := make([]int, d, d)
+	l := make([]int, d, d)
+	for i := range l {
+		off, err := dec.readUint32()
+		if err != nil {
+			return fmt.Errorf("could not read offset of dimension %d: %v", i+1, err)
+		}
+		o[i] = int(off)
+		s, err := dec.readUint32()
+		if err != nil {
+			return fmt.Errorf("could not read actual count of dimension %d: %v", i+1, err)
+		}
+		if m[i] < int(s)+int(off) {
+			m[i] = int(s) + int(off)
+		}
+		l[i] = int(s)
+	}
+	// Initialise size of slices
+	//   Initialise the size of the 1st dimension
+	ty := v.Type()
+	v.Set(reflect.MakeSlice(ty, m[0], m[0]))
+	// Initialise the size of the other dimensions recursively
+	makeSubSlices(v, m[1:])
+
+	// Get all permutations of the indexes and go through each and fill
+	ps := multiDimensionalIndexPermutations(m)
+	for _, p := range ps {
+		// Get current multi-dimensional index to fill
+		a := v
+		var os bool // should this permutation be skipped due to the offset of any of the dimensions or max is higher than the actual count being passed
+		for i, j := range p {
+			if j < o[i] || j >= l[i] {
+				os = true
+				break
+			}
+			a = a.Index(j)
+		}
+		if os {
+			// This permutation should be skipped as it is less than the offset for one of the dimensions.
+			continue
+		}
+		err := dec.fill(a, tag, def)
+		if err != nil {
+			return fmt.Errorf("could not fill index %v of slice: %v", p, err)
+		}
+	}
+	return nil
+}

vendor/github.com/jcmturner/rpc/v2/ndr/decoder.go

@@ -0,0 +1,393 @@
+// Package ndr provides the ability to unmarshal NDR encoded byte steams into Go data structures
+package ndr
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"reflect"
+	"strings"
+)
+
+// Struct tag values
+const (
+	TagConformant = "conformant"
+	TagVarying    = "varying"
+	TagPointer    = "pointer"
+	TagPipe       = "pipe"
+)
+
+// Decoder unmarshals NDR byte stream data into a Go struct representation
+type Decoder struct {
+	r             *bufio.Reader // source of the data
+	size          int           // initial size of bytes in buffer
+	ch            CommonHeader  // NDR common header
+	ph            PrivateHeader // NDR private header
+	conformantMax []uint32      // conformant max values that were moved to the beginning of the structure
+	s             interface{}   // pointer to the structure being populated
+	current       []string      // keeps track of the current field being populated
+}
+
+type deferedPtr struct {
+	v   reflect.Value
+	tag reflect.StructTag
+}
+
+// NewDecoder creates a new instance of a NDR Decoder.
+func NewDecoder(r io.Reader) *Decoder {
+	dec := new(Decoder)
+	dec.r = bufio.NewReader(r)
+	dec.r.Peek(int(commonHeaderBytes)) // For some reason an operation is needed on the buffer to initialise it so Buffered() != 0
+	dec.size = dec.r.Buffered()
+	return dec
+}
+
+// Decode unmarshals the NDR encoded bytes into the pointer of a struct provided.
+func (dec *Decoder) Decode(s interface{}) error {
+	dec.s = s
+	err := dec.readCommonHeader()
+	if err != nil {
+		return err
+	}
+	err = dec.readPrivateHeader()
+	if err != nil {
+		return err
+	}
+	_, err = dec.r.Discard(4) //The next 4 bytes are an RPC unique pointer referent. We just skip these.
+	if err != nil {
+		return Errorf("unable to process byte stream: %v", err)
+	}
+
+	return dec.process(s, reflect.StructTag(""))
+}
+
+func (dec *Decoder) process(s interface{}, tag reflect.StructTag) error {
+	// Scan for conformant fields as their max counts are moved to the beginning
+	// http://pubs.opengroup.org/onlinepubs/9629399/chap14.htm#tagfcjh_37
+	err := dec.scanConformantArrays(s, tag)
+	if err != nil {
+		return err
+	}
+	// Recursively fill the struct fields
+	var localDef []deferedPtr
+	err = dec.fill(s, tag, &localDef)
+	if err != nil {
+		return Errorf("could not decode: %v", err)
+	}
+	// Read any deferred referents associated with pointers
+	for _, p := range localDef {
+		err = dec.process(p.v, p.tag)
+		if err != nil {
+			return fmt.Errorf("could not decode deferred referent: %v", err)
+		}
+	}
+	return nil
+}
+
+// scanConformantArrays scans the structure for embedded conformant fields and captures the maximum element counts for
+// dimensions of the array that are moved to the beginning of the structure.
+func (dec *Decoder) scanConformantArrays(s interface{}, tag reflect.StructTag) error {
+	err := dec.conformantScan(s, tag)
+	if err != nil {
+		return fmt.Errorf("failed to scan for embedded conformant arrays: %v", err)
+	}
+	for i := range dec.conformantMax {
+		dec.conformantMax[i], err = dec.readUint32()
+		if err != nil {
+			return fmt.Errorf("could not read preceding conformant max count index %d: %v", i, err)
+		}
+	}
+	return nil
+}
+
+// conformantScan inspects the structure's fields for whether they are conformant.
+func (dec *Decoder) conformantScan(s interface{}, tag reflect.StructTag) error {
+	ndrTag := parseTags(tag)
+	if ndrTag.HasValue(TagPointer) {
+		return nil
+	}
+	v := getReflectValue(s)
+	switch v.Kind() {
+	case reflect.Struct:
+		for i := 0; i < v.NumField(); i++ {
+			err := dec.conformantScan(v.Field(i), v.Type().Field(i).Tag)
+			if err != nil {
+				return err
+			}
+		}
+	case reflect.String:
+		if !ndrTag.HasValue(TagConformant) {
+			break
+		}
+		dec.conformantMax = append(dec.conformantMax, uint32(0))
+	case reflect.Slice:
+		if !ndrTag.HasValue(TagConformant) {
+			break
+		}
+		d, t := sliceDimensions(v.Type())
+		for i := 0; i < d; i++ {
+			dec.conformantMax = append(dec.conformantMax, uint32(0))
+		}
+		// For string arrays there is a common max for the strings within the array.
+		if t.Kind() == reflect.String {
+			dec.conformantMax = append(dec.conformantMax, uint32(0))
+		}
+	}
+	return nil
+}
+
+func (dec *Decoder) isPointer(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) (bool, error) {
+	// Pointer so defer filling the referent
+	ndrTag := parseTags(tag)
+	if ndrTag.HasValue(TagPointer) {
+		p, err := dec.readUint32()
+		if err != nil {
+			return true, fmt.Errorf("could not read pointer: %v", err)
+		}
+		ndrTag.delete(TagPointer)
+		if p != 0 {
+			// if pointer is not zero add to the deferred items at end of stream
+			*def = append(*def, deferedPtr{v, ndrTag.StructTag()})
+		}
+		return true, nil
+	}
+	return false, nil
+}
+
+func getReflectValue(s interface{}) (v reflect.Value) {
+	if r, ok := s.(reflect.Value); ok {
+		v = r
+	} else {
+		if reflect.ValueOf(s).Kind() == reflect.Ptr {
+			v = reflect.ValueOf(s).Elem()
+		}
+	}
+	return
+}
+
+// fill populates fields with values from the NDR byte stream.
+func (dec *Decoder) fill(s interface{}, tag reflect.StructTag, localDef *[]deferedPtr) error {
+	v := getReflectValue(s)
+
+	//// Pointer so defer filling the referent
+	ptr, err := dec.isPointer(v, tag, localDef)
+	if err != nil {
+		return fmt.Errorf("could not process struct field(%s): %v", strings.Join(dec.current, "/"), err)
+	}
+	if ptr {
+		return nil
+	}
+
+	// Populate the value from the byte stream
+	switch v.Kind() {
+	case reflect.Struct:
+		dec.current = append(dec.current, v.Type().Name()) //Track the current field being filled
+		// in case struct is a union, track this and the selected union field for efficiency
+		var unionTag reflect.Value
+		var unionField string // field to fill if struct is a union
+		// Go through each field in the struct and recursively fill
+		for i := 0; i < v.NumField(); i++ {
+			fieldName := v.Type().Field(i).Name
+			dec.current = append(dec.current, fieldName) //Track the current field being filled
+			//fmt.Fprintf(os.Stderr, "DEBUG Decoding: %s\n", strings.Join(dec.current, "/"))
+			structTag := v.Type().Field(i).Tag
+			ndrTag := parseTags(structTag)
+
+			// Union handling
+			if !unionTag.IsValid() {
+				// Is this field a union tag?
+				unionTag = dec.isUnion(v.Field(i), structTag)
+			} else {
+				// What is the selected field value of the union if we don't already know
+				if unionField == "" {
+					unionField, err = unionSelectedField(v, unionTag)
+					if err != nil {
+						return fmt.Errorf("could not determine selected union value field for %s with discriminat"+
+							" tag %s: %v", v.Type().Name(), unionTag, err)
+					}
+				}
+				if ndrTag.HasValue(TagUnionField) && fieldName != unionField {
+					// is a union and this field has not been selected so will skip it.
+					dec.current = dec.current[:len(dec.current)-1] //This field has been skipped so remove it from the current field tracker
+					continue
+				}
+			}
+
+			// Check if field is a pointer
+			if v.Field(i).Type().Implements(reflect.TypeOf(new(RawBytes)).Elem()) &&
+				v.Field(i).Type().Kind() == reflect.Slice && v.Field(i).Type().Elem().Kind() == reflect.Uint8 {
+				//field is for rawbytes
+				structTag, err = addSizeToTag(v, v.Field(i), structTag)
+				if err != nil {
+					return fmt.Errorf("could not get rawbytes field(%s) size: %v", strings.Join(dec.current, "/"), err)
+				}
+				ptr, err := dec.isPointer(v.Field(i), structTag, localDef)
+				if err != nil {
+					return fmt.Errorf("could not process struct field(%s): %v", strings.Join(dec.current, "/"), err)
+				}
+				if !ptr {
+					err := dec.readRawBytes(v.Field(i), structTag)
+					if err != nil {
+						return fmt.Errorf("could not fill raw bytes struct field(%s): %v", strings.Join(dec.current, "/"), err)
+					}
+				}
+			} else {
+				err := dec.fill(v.Field(i), structTag, localDef)
+				if err != nil {
+					return fmt.Errorf("could not fill struct field(%s): %v", strings.Join(dec.current, "/"), err)
+				}
+			}
+			dec.current = dec.current[:len(dec.current)-1] //This field has been filled so remove it from the current field tracker
+		}
+		dec.current = dec.current[:len(dec.current)-1] //This field has been filled so remove it from the current field tracker
+	case reflect.Bool:
+		i, err := dec.readBool()
+		if err != nil {
+			return fmt.Errorf("could not fill %s: %v", v.Type().Name(), err)
+		}
+		v.Set(reflect.ValueOf(i))
+	case reflect.Uint8:
+		i, err := dec.readUint8()
+		if err != nil {
+			return fmt.Errorf("could not fill %s: %v", v.Type().Name(), err)
+		}
+		v.Set(reflect.ValueOf(i))
+	case reflect.Uint16:
+		i, err := dec.readUint16()
+		if err != nil {
+			return fmt.Errorf("could not fill %s: %v", v.Type().Name(), err)
+		}
+		v.Set(reflect.ValueOf(i))
+	case reflect.Uint32:
+		i, err := dec.readUint32()
+		if err != nil {
+			return fmt.Errorf("could not fill %s: %v", v.Type().Name(), err)
+		}
+		v.Set(reflect.ValueOf(i))
+	case reflect.Uint64:
+		i, err := dec.readUint64()
+		if err != nil {
+			return fmt.Errorf("could not fill %s: %v", v.Type().Name(), err)
+		}
+		v.Set(reflect.ValueOf(i))
+	case reflect.Int8:
+		i, err := dec.readInt8()
+		if err != nil {
+			return fmt.Errorf("could not fill %s: %v", v.Type().Name(), err)
+		}
+		v.Set(reflect.ValueOf(i))
+	case reflect.Int16:
+		i, err := dec.readInt16()
+		if err != nil {
+			return fmt.Errorf("could not fill %s: %v", v.Type().Name(), err)
+		}
+		v.Set(reflect.ValueOf(i))
+	case reflect.Int32:
+		i, err := dec.readInt32()
+		if err != nil {
+			return fmt.Errorf("could not fill %s: %v", v.Type().Name(), err)
+		}
+		v.Set(reflect.ValueOf(i))
+	case reflect.Int64:
+		i, err := dec.readInt64()
+		if err != nil {
+			return fmt.Errorf("could not fill %s: %v", v.Type().Name(), err)
+		}
+		v.Set(reflect.ValueOf(i))
+	case reflect.String:
+		ndrTag := parseTags(tag)
+		conformant := ndrTag.HasValue(TagConformant)
+		// strings are always varying so this is assumed without an explicit tag
+		var s string
+		var err error
+		if conformant {
+			s, err = dec.readConformantVaryingString(localDef)
+			if err != nil {
+				return fmt.Errorf("could not fill with conformant varying string: %v", err)
+			}
+		} else {
+			s, err = dec.readVaryingString(localDef)
+			if err != nil {
+				return fmt.Errorf("could not fill with varying string: %v", err)
+			}
+		}
+		v.Set(reflect.ValueOf(s))
+	case reflect.Float32:
+		i, err := dec.readFloat32()
+		if err != nil {
+			return fmt.Errorf("could not fill %v: %v", v.Type().Name(), err)
+		}
+		v.Set(reflect.ValueOf(i))
+	case reflect.Float64:
+		i, err := dec.readFloat64()
+		if err != nil {
+			return fmt.Errorf("could not fill %v: %v", v.Type().Name(), err)
+		}
+		v.Set(reflect.ValueOf(i))
+	case reflect.Array:
+		err := dec.fillFixedArray(v, tag, localDef)
+		if err != nil {
+			return err
+		}
+	case reflect.Slice:
+		if v.Type().Implements(reflect.TypeOf(new(RawBytes)).Elem()) && v.Type().Elem().Kind() == reflect.Uint8 {
+			//field is for rawbytes
+			err := dec.readRawBytes(v, tag)
+			if err != nil {
+				return fmt.Errorf("could not fill raw bytes struct field(%s): %v", strings.Join(dec.current, "/"), err)
+			}
+			break
+		}
+		ndrTag := parseTags(tag)
+		conformant := ndrTag.HasValue(TagConformant)
+		varying := ndrTag.HasValue(TagVarying)
+		if ndrTag.HasValue(TagPipe) {
+			err := dec.fillPipe(v, tag)
+			if err != nil {
+				return err
+			}
+			break
+		}
+		_, t := sliceDimensions(v.Type())
+		if t.Kind() == reflect.String && !ndrTag.HasValue(subStringArrayValue) {
+			// String array
+			err := dec.readStringsArray(v, tag, localDef)
+			if err != nil {
+				return err
+			}
+			break
+		}
+		// varying is assumed as fixed arrays use the Go array type rather than slice
+		if conformant && varying {
+			err := dec.fillConformantVaryingArray(v, tag, localDef)
+			if err != nil {
+				return err
+			}
+		} else if !conformant && varying {
+			err := dec.fillVaryingArray(v, tag, localDef)
+			if err != nil {
+				return err
+			}
+		} else {
+			//default to conformant and not varying
+			err := dec.fillConformantArray(v, tag, localDef)
+			if err != nil {
+				return err
+			}
+		}
+	default:
+		return fmt.Errorf("unsupported type")
+	}
+	return nil
+}
+
+// readBytes returns a number of bytes from the NDR byte stream.
+func (dec *Decoder) readBytes(n int) ([]byte, error) {
+	//TODO make this take an int64 as input to allow for larger values on all systems?
+	b := make([]byte, n, n)
+	m, err := dec.r.Read(b)
+	if err != nil || m != n {
+		return b, fmt.Errorf("error reading bytes from stream: %v", err)
+	}
+	return b, nil
+}

vendor/github.com/jcmturner/rpc/v2/ndr/error.go

@@ -0,0 +1,18 @@
+package ndr
+
+import "fmt"
+
+// Malformed implements the error interface for malformed NDR encoding errors.
+type Malformed struct {
+	EText string
+}
+
+// Error implements the error interface on the Malformed struct.
+func (e Malformed) Error() string {
+	return fmt.Sprintf("malformed NDR stream: %s", e.EText)
+}
+
+// Errorf formats an error message into a malformed NDR error.
+func Errorf(format string, a ...interface{}) Malformed {
+	return Malformed{EText: fmt.Sprintf(format, a...)}
+}

vendor/github.com/jcmturner/rpc/v2/ndr/header.go

@@ -0,0 +1,116 @@
+package ndr
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+/*
+Serialization Version 1
+https://msdn.microsoft.com/en-us/library/cc243563.aspx
+
+Common Header - https://msdn.microsoft.com/en-us/library/cc243890.aspx
+8 bytes in total:
+- First byte - Version: Must equal 1
+- Second byte -  1st 4 bits: Endianess (0=Big; 1=Little); 2nd 4 bits: Character Encoding (0=ASCII; 1=EBCDIC)
+- 3rd - Floating point representation (This does not seem to be the case in examples for Microsoft test sources)
+- 4th - Common Header Length: Must equal 8
+- 5th - 8th - Filler: MUST be set to 0xcccccccc on marshaling, and SHOULD be ignored during unmarshaling.
+
+Private Header - https://msdn.microsoft.com/en-us/library/cc243919.aspx
+8 bytes in total:
+- First 4 bytes - Indicates the length of a serialized top-level type in the octet stream. It MUST include the padding length and exclude the header itself.
+- Second 4 bytes - Filler: MUST be set to 0 (zero) during marshaling, and SHOULD be ignored during unmarshaling.
+*/
+
+const (
+	protocolVersion   uint8  = 1
+	commonHeaderBytes uint16 = 8
+	bigEndian                = 0
+	littleEndian             = 1
+	ascii             uint8  = 0
+	ebcdic            uint8  = 1
+	ieee              uint8  = 0
+	vax               uint8  = 1
+	cray              uint8  = 2
+	ibm               uint8  = 3
+)
+
+// CommonHeader implements the NDR common header: https://msdn.microsoft.com/en-us/library/cc243889.aspx
+type CommonHeader struct {
+	Version             uint8
+	Endianness          binary.ByteOrder
+	CharacterEncoding   uint8
+	FloatRepresentation uint8
+	HeaderLength        uint16
+	Filler              []byte
+}
+
+// PrivateHeader implements the NDR private header: https://msdn.microsoft.com/en-us/library/cc243919.aspx
+type PrivateHeader struct {
+	ObjectBufferLength uint32
+	Filler             []byte
+}
+
+func (dec *Decoder) readCommonHeader() error {
+	// Version
+	vb, err := dec.r.ReadByte()
+	if err != nil {
+		return Malformed{EText: "could not read first byte of common header for version"}
+	}
+	dec.ch.Version = uint8(vb)
+	if dec.ch.Version != protocolVersion {
+		return Malformed{EText: fmt.Sprintf("byte stream does not indicate a RPC Type serialization of version %v", protocolVersion)}
+	}
+	// Read Endianness & Character Encoding
+	eb, err := dec.r.ReadByte()
+	if err != nil {
+		return Malformed{EText: "could not read second byte of common header for endianness"}
+	}
+	endian := int(eb >> 4 & 0xF)
+	if endian != 0 && endian != 1 {
+		return Malformed{EText: "common header does not indicate a valid endianness"}
+	}
+	dec.ch.CharacterEncoding = uint8(vb & 0xF)
+	if dec.ch.CharacterEncoding != 0 && dec.ch.CharacterEncoding != 1 {
+		return Malformed{EText: "common header does not indicate a valid character encoding"}
+	}
+	switch endian {
+	case littleEndian:
+		dec.ch.Endianness = binary.LittleEndian
+	case bigEndian:
+		dec.ch.Endianness = binary.BigEndian
+	}
+	// Common header length
+	lb, err := dec.readBytes(2)
+	if err != nil {
+		return Malformed{EText: fmt.Sprintf("could not read common header length: %v", err)}
+	}
+	dec.ch.HeaderLength = dec.ch.Endianness.Uint16(lb)
+	if dec.ch.HeaderLength != commonHeaderBytes {
+		return Malformed{EText: "common header does not indicate a valid length"}
+	}
+	// Filler bytes
+	dec.ch.Filler, err = dec.readBytes(4)
+	if err != nil {
+		return Malformed{EText: fmt.Sprintf("could not read common header filler: %v", err)}
+	}
+	return nil
+}
+
+func (dec *Decoder) readPrivateHeader() error {
+	// The next 8 bytes after the common header comprise the RPC type marshalling private header for constructed types.
+	err := binary.Read(dec.r, dec.ch.Endianness, &dec.ph.ObjectBufferLength)
+	if err != nil {
+		return Malformed{EText: "could not read private header object buffer length"}
+	}
+	if dec.ph.ObjectBufferLength%8 != 0 {
+		return Malformed{EText: "object buffer length not a multiple of 8"}
+	}
+	// Filler bytes
+	dec.ph.Filler, err = dec.readBytes(4)
+	if err != nil {
+		return Malformed{EText: fmt.Sprintf("could not read private header filler: %v", err)}
+	}
+	return nil
+}

vendor/github.com/jcmturner/rpc/v2/ndr/pipe.go

@@ -0,0 +1,31 @@
+package ndr
+
+import (
+	"fmt"
+	"reflect"
+)
+
+func (dec *Decoder) fillPipe(v reflect.Value, tag reflect.StructTag) error {
+	s, err := dec.readUint32() // read element count of first chunk
+	if err != nil {
+		return err
+	}
+	a := reflect.MakeSlice(v.Type(), 0, 0)
+	c := reflect.MakeSlice(v.Type(), int(s), int(s))
+	for s != 0 {
+		for i := 0; i < int(s); i++ {
+			err := dec.fill(c.Index(i), tag, &[]deferedPtr{})
+			if err != nil {
+				return fmt.Errorf("could not fill element %d of pipe: %v", i, err)
+			}
+		}
+		s, err = dec.readUint32() // read element count of first chunk
+		if err != nil {
+			return err
+		}
+		a = reflect.AppendSlice(a, c)
+		c = reflect.MakeSlice(v.Type(), int(s), int(s))
+	}
+	v.Set(a)
+	return nil
+}

vendor/github.com/jcmturner/rpc/v2/ndr/primitives.go

@@ -0,0 +1,211 @@
+package ndr
+
+import (
+	"bytes"
+	"encoding/binary"
+	"math"
+)
+
+// Byte sizes of primitive types
+const (
+	SizeBool   = 1
+	SizeChar   = 1
+	SizeUint8  = 1
+	SizeUint16 = 2
+	SizeUint32 = 4
+	SizeUint64 = 8
+	SizeEnum   = 2
+	SizeSingle = 4
+	SizeDouble = 8
+	SizePtr    = 4
+)
+
+// Bool is an NDR Boolean which is a logical quantity that assumes one of two values: TRUE or FALSE.
+// NDR represents a Boolean as one octet.
+// It represents a value of FALSE as a zero octet, an octet in which every bit is reset.
+// It represents a value of TRUE as a non-zero octet, an octet in which one or more bits are set.
+
+// Char is an NDR character.
+// NDR represents a character as one octet.
+// Characters have two representation formats: ASCII and EBCDIC.
+
+// USmall is an unsigned 8 bit integer
+
+// UShort is an unsigned 16 bit integer
+
+// ULong is an unsigned 32 bit integer
+
+// UHyper is an unsigned 64 bit integer
+
+// Small is an signed 8 bit integer
+
+// Short is an signed 16 bit integer
+
+// Long is an signed 32 bit integer
+
+// Hyper is an signed 64 bit integer
+
+// Enum is the NDR representation of enumerated types as signed short integers (2 octets)
+
+// Single is an NDR defined single-precision floating-point data type
+
+// Double is an NDR defined double-precision floating-point data type
+
+// readBool reads a byte representing a boolean.
+// NDR represents a Boolean as one octet.
+// It represents a value of FALSE as a zero octet, an octet in which every bit is reset.
+// It represents a value of TRUE as a non-zero octet, an octet in which one or more bits are set.
+func (dec *Decoder) readBool() (bool, error) {
+	i, err := dec.readUint8()
+	if err != nil {
+		return false, err
+	}
+	if i != 0 {
+		return true, nil
+	}
+	return false, nil
+}
+
+// readChar reads bytes representing a 8bit ASCII integer cast to a rune.
+func (dec *Decoder) readChar() (rune, error) {
+	var r rune
+	a, err := dec.readUint8()
+	if err != nil {
+		return r, err
+	}
+	return rune(a), nil
+}
+
+// readUint8 reads bytes representing a 8bit unsigned integer.
+func (dec *Decoder) readUint8() (uint8, error) {
+	b, err := dec.r.ReadByte()
+	if err != nil {
+		return uint8(0), err
+	}
+	return uint8(b), nil
+}
+
+// readUint16 reads bytes representing a 16bit unsigned integer.
+func (dec *Decoder) readUint16() (uint16, error) {
+	dec.ensureAlignment(SizeUint16)
+	b, err := dec.readBytes(SizeUint16)
+	if err != nil {
+		return uint16(0), err
+	}
+	return dec.ch.Endianness.Uint16(b), nil
+}
+
+// readUint32 reads bytes representing a 32bit unsigned integer.
+func (dec *Decoder) readUint32() (uint32, error) {
+	dec.ensureAlignment(SizeUint32)
+	b, err := dec.readBytes(SizeUint32)
+	if err != nil {
+		return uint32(0), err
+	}
+	return dec.ch.Endianness.Uint32(b), nil
+}
+
+// readUint32 reads bytes representing a 32bit unsigned integer.
+func (dec *Decoder) readUint64() (uint64, error) {
+	dec.ensureAlignment(SizeUint64)
+	b, err := dec.readBytes(SizeUint64)
+	if err != nil {
+		return uint64(0), err
+	}
+	return dec.ch.Endianness.Uint64(b), nil
+}
+
+func (dec *Decoder) readInt8() (int8, error) {
+	dec.ensureAlignment(SizeUint8)
+	b, err := dec.readBytes(SizeUint8)
+	if err != nil {
+		return 0, err
+	}
+	var i int8
+	buf := bytes.NewReader(b)
+	err = binary.Read(buf, dec.ch.Endianness, &i)
+	if err != nil {
+		return 0, err
+	}
+	return i, nil
+}
+
+func (dec *Decoder) readInt16() (int16, error) {
+	dec.ensureAlignment(SizeUint16)
+	b, err := dec.readBytes(SizeUint16)
+	if err != nil {
+		return 0, err
+	}
+	var i int16
+	buf := bytes.NewReader(b)
+	err = binary.Read(buf, dec.ch.Endianness, &i)
+	if err != nil {
+		return 0, err
+	}
+	return i, nil
+}
+
+func (dec *Decoder) readInt32() (int32, error) {
+	dec.ensureAlignment(SizeUint32)
+	b, err := dec.readBytes(SizeUint32)
+	if err != nil {
+		return 0, err
+	}
+	var i int32
+	buf := bytes.NewReader(b)
+	err = binary.Read(buf, dec.ch.Endianness, &i)
+	if err != nil {
+		return 0, err
+	}
+	return i, nil
+}
+
+func (dec *Decoder) readInt64() (int64, error) {
+	dec.ensureAlignment(SizeUint64)
+	b, err := dec.readBytes(SizeUint64)
+	if err != nil {
+		return 0, err
+	}
+	var i int64
+	buf := bytes.NewReader(b)
+	err = binary.Read(buf, dec.ch.Endianness, &i)
+	if err != nil {
+		return 0, err
+	}
+	return i, nil
+}
+
+// https://en.wikipedia.org/wiki/IEEE_754-1985
+func (dec *Decoder) readFloat32() (f float32, err error) {
+	dec.ensureAlignment(SizeSingle)
+	b, err := dec.readBytes(SizeSingle)
+	if err != nil {
+		return
+	}
+	bits := dec.ch.Endianness.Uint32(b)
+	f = math.Float32frombits(bits)
+	return
+}
+
+func (dec *Decoder) readFloat64() (f float64, err error) {
+	dec.ensureAlignment(SizeDouble)
+	b, err := dec.readBytes(SizeDouble)
+	if err != nil {
+		return
+	}
+	bits := dec.ch.Endianness.Uint64(b)
+	f = math.Float64frombits(bits)
+	return
+}
+
+// NDR enforces NDR alignment of primitive data; that is, any primitive of size n octets is aligned at a octet stream
+// index that is a multiple of n. (In this version of NDR, n is one of {1, 2, 4, 8}.) An octet stream index indicates
+// the number of an octet in an octet stream when octets are numbered, beginning with 0, from the first octet in the
+// stream. Where necessary, an alignment gap, consisting of octets of unspecified value, precedes the representation
+// of a primitive. The gap is of the smallest size sufficient to align the primitive.
+func (dec *Decoder) ensureAlignment(n int) {
+	p := dec.size - dec.r.Buffered()
+	if s := p % n; s != 0 {
+		dec.r.Discard(n - s)
+	}
+}

vendor/github.com/jcmturner/rpc/v2/ndr/rawbytes.go

@@ -0,0 +1,61 @@
+package ndr
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"strconv"
+)
+
+// type MyBytes []byte
+// implement RawBytes interface
+
+const (
+	sizeMethod = "Size"
+)
+
+// RawBytes interface should be implemented if reading just a number of bytes from the NDR stream
+type RawBytes interface {
+	Size(interface{}) int
+}
+
+func rawBytesSize(parent reflect.Value, v reflect.Value) (int, error) {
+	sf := v.MethodByName(sizeMethod)
+	if !sf.IsValid() {
+		return 0, fmt.Errorf("could not find a method called %s on the implementation of RawBytes", sizeMethod)
+	}
+	in := []reflect.Value{parent}
+	f := sf.Call(in)
+	if f[0].Kind() != reflect.Int {
+		return 0, errors.New("the RawBytes size function did not return an integer")
+	}
+	return int(f[0].Int()), nil
+}
+
+func addSizeToTag(parent reflect.Value, v reflect.Value, tag reflect.StructTag) (reflect.StructTag, error) {
+	size, err := rawBytesSize(parent, v)
+	if err != nil {
+		return tag, err
+	}
+	ndrTag := parseTags(tag)
+	ndrTag.Map["size"] = strconv.Itoa(size)
+	return ndrTag.StructTag(), nil
+}
+
+func (dec *Decoder) readRawBytes(v reflect.Value, tag reflect.StructTag) error {
+	ndrTag := parseTags(tag)
+	sizeStr, ok := ndrTag.Map["size"]
+	if !ok {
+		return errors.New("size tag not available")
+	}
+	size, err := strconv.Atoi(sizeStr)
+	if err != nil {
+		return fmt.Errorf("size not valid: %v", err)
+	}
+	b, err := dec.readBytes(size)
+	if err != nil {
+		return err
+	}
+	v.Set(reflect.ValueOf(b).Convert(v.Type()))
+	return nil
+}

vendor/github.com/jcmturner/rpc/v2/ndr/strings.go

@@ -0,0 +1,70 @@
+package ndr
+
+import (
+	"fmt"
+	"reflect"
+)
+
+const (
+	subStringArrayTag   = `ndr:"varying,X-subStringArray"`
+	subStringArrayValue = "X-subStringArray"
+)
+
+func uint16SliceToString(a []uint16) string {
+	s := make([]rune, len(a), len(a))
+	for i := range s {
+		s[i] = rune(a[i])
+	}
+	if len(s) > 0 {
+		// Remove any null terminator
+		if s[len(s)-1] == rune(0) {
+			s = s[:len(s)-1]
+		}
+	}
+	return string(s)
+}
+
+func (dec *Decoder) readVaryingString(def *[]deferedPtr) (string, error) {
+	a := new([]uint16)
+	v := reflect.ValueOf(a)
+	var t reflect.StructTag
+	err := dec.fillUniDimensionalVaryingArray(v.Elem(), t, def)
+	if err != nil {
+		return "", err
+	}
+	s := uint16SliceToString(*a)
+	return s, nil
+}
+
+func (dec *Decoder) readConformantVaryingString(def *[]deferedPtr) (string, error) {
+	a := new([]uint16)
+	v := reflect.ValueOf(a)
+	var t reflect.StructTag
+	err := dec.fillUniDimensionalConformantVaryingArray(v.Elem(), t, def)
+	if err != nil {
+		return "", err
+	}
+	s := uint16SliceToString(*a)
+	return s, nil
+}
+
+func (dec *Decoder) readStringsArray(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) error {
+	d, _ := sliceDimensions(v.Type())
+	ndrTag := parseTags(tag)
+	var m []int
+	//var ms int
+	if ndrTag.HasValue(TagConformant) {
+		for i := 0; i < d; i++ {
+			m = append(m, int(dec.precedingMax()))
+		}
+		//common max size
+		_ = dec.precedingMax()
+		//ms = int(n)
+	}
+	tag = reflect.StructTag(subStringArrayTag)
+	err := dec.fillVaryingArray(v, tag, def)
+	if err != nil {
+		return fmt.Errorf("could not read string array: %v", err)
+	}
+	return nil
+}

vendor/github.com/jcmturner/rpc/v2/ndr/tags.go

@@ -0,0 +1,69 @@
+package ndr
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+)
+
+const ndrNameSpace = "ndr"
+
+type tags struct {
+	Values []string
+	Map    map[string]string
+}
+
+// parse the struct field tags and extract the ndr related ones.
+// format of tag ndr:"value,key:value1,value2"
+func parseTags(st reflect.StructTag) tags {
+	s := st.Get(ndrNameSpace)
+	t := tags{
+		Values: []string{},
+		Map:    make(map[string]string),
+	}
+	if s != "" {
+		ndrTags := strings.Trim(s, `"`)
+		for _, tag := range strings.Split(ndrTags, ",") {
+			if strings.Contains(tag, ":") {
+				m := strings.SplitN(tag, ":", 2)
+				t.Map[m[0]] = m[1]
+			} else {
+				t.Values = append(t.Values, tag)
+			}
+		}
+	}
+	return t
+}
+
+func appendTag(t reflect.StructTag, s string) reflect.StructTag {
+	ts := t.Get(ndrNameSpace)
+	ts = fmt.Sprintf(`%s"%s,%s"`, ndrNameSpace, ts, s)
+	return reflect.StructTag(ts)
+}
+
+func (t *tags) StructTag() reflect.StructTag {
+	mv := t.Values
+	for key, val := range t.Map {
+		mv = append(mv, key+":"+val)
+	}
+	s := ndrNameSpace + ":" + `"` + strings.Join(mv, ",") + `"`
+	return reflect.StructTag(s)
+}
+
+func (t *tags) delete(s string) {
+	for i, x := range t.Values {
+		if x == s {
+			t.Values = append(t.Values[:i], t.Values[i+1:]...)
+		}
+	}
+	delete(t.Map, s)
+}
+
+func (t *tags) HasValue(s string) bool {
+	for _, v := range t.Values {
+		if v == s {
+			return true
+		}
+	}
+	return false
+}

vendor/github.com/jcmturner/rpc/v2/ndr/union.go

@@ -0,0 +1,57 @@
+package ndr
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+)
+
+// Union interface must be implemented by structs that will be unmarshaled into from the NDR byte stream union representation.
+// The union's discriminating tag will be passed to the SwitchFunc method.
+// The discriminating tag field must have the struct tag: `ndr:"unionTag"`
+// If the union is encapsulated the discriminating tag field must have the struct tag: `ndr:"encapsulated"`
+// The possible value fields that can be selected from must have the struct tag: `ndr:"unionField"`
+type Union interface {
+	SwitchFunc(t interface{}) string
+}
+
+// Union related constants such as struct tag values
+const (
+	unionSelectionFuncName = "SwitchFunc"
+	TagEncapsulated        = "encapsulated"
+	TagUnionTag            = "unionTag"
+	TagUnionField          = "unionField"
+)
+
+func (dec *Decoder) isUnion(field reflect.Value, tag reflect.StructTag) (r reflect.Value) {
+	ndrTag := parseTags(tag)
+	if !ndrTag.HasValue(TagUnionTag) {
+		return
+	}
+	r = field
+	// For a non-encapsulated union, the discriminant is marshalled into the transmitted data stream twice: once as the
+	// field or parameter, which is referenced by the switch_is construct, in the procedure argument list; and once as
+	// the first part of the union representation.
+	if !ndrTag.HasValue(TagEncapsulated) {
+		dec.r.Discard(int(r.Type().Size()))
+	}
+	return
+}
+
+// unionSelectedField returns the field name of which of the union values to fill
+func unionSelectedField(union, discriminant reflect.Value) (string, error) {
+	if !union.Type().Implements(reflect.TypeOf(new(Union)).Elem()) {
+		return "", errors.New("struct does not implement union interface")
+	}
+	args := []reflect.Value{discriminant}
+	// Call the SelectFunc of the union struct to find the name of the field to fill with the value selected.
+	sf := union.MethodByName(unionSelectionFuncName)
+	if !sf.IsValid() {
+		return "", fmt.Errorf("could not find a selection function called %s in the unions struct representation", unionSelectionFuncName)
+	}
+	f := sf.Call(args)
+	if f[0].Kind() != reflect.String || f[0].String() == "" {
+		return "", fmt.Errorf("the union select function did not return a string for the name of the field to fill")
+	}
+	return f[0].String(), nil
+}