traefik/vendor/github.com/tinylib/msgp/msgp/write.go
2018-06-28 18:40:04 +02:00

845 lines
19 KiB
Go

package msgp
import (
"errors"
"fmt"
"io"
"math"
"reflect"
"sync"
"time"
)
// Sizer is an interface implemented
// by types that can estimate their
// size when MessagePack encoded.
// This interface is optional, but
// encoding/marshaling implementations
// may use this as a way to pre-allocate
// memory for serialization.
type Sizer interface {
Msgsize() int
}
var (
// Nowhere is an io.Writer to nowhere
Nowhere io.Writer = nwhere{}
btsType = reflect.TypeOf(([]byte)(nil))
writerPool = sync.Pool{
New: func() interface{} {
return &Writer{buf: make([]byte, 2048)}
},
}
)
func popWriter(w io.Writer) *Writer {
wr := writerPool.Get().(*Writer)
wr.Reset(w)
return wr
}
func pushWriter(wr *Writer) {
wr.w = nil
wr.wloc = 0
writerPool.Put(wr)
}
// freeW frees a writer for use
// by other processes. It is not necessary
// to call freeW on a writer. However, maintaining
// a reference to a *Writer after calling freeW on
// it will cause undefined behavior.
func freeW(w *Writer) { pushWriter(w) }
// Require ensures that cap(old)-len(old) >= extra.
func Require(old []byte, extra int) []byte {
l := len(old)
c := cap(old)
r := l + extra
if c >= r {
return old
} else if l == 0 {
return make([]byte, 0, extra)
}
// the new size is the greater
// of double the old capacity
// and the sum of the old length
// and the number of new bytes
// necessary.
c <<= 1
if c < r {
c = r
}
n := make([]byte, l, c)
copy(n, old)
return n
}
// nowhere writer
type nwhere struct{}
func (n nwhere) Write(p []byte) (int, error) { return len(p), nil }
// Marshaler is the interface implemented
// by types that know how to marshal themselves
// as MessagePack. MarshalMsg appends the marshalled
// form of the object to the provided
// byte slice, returning the extended
// slice and any errors encountered.
type Marshaler interface {
MarshalMsg([]byte) ([]byte, error)
}
// Encodable is the interface implemented
// by types that know how to write themselves
// as MessagePack using a *msgp.Writer.
type Encodable interface {
EncodeMsg(*Writer) error
}
// Writer is a buffered writer
// that can be used to write
// MessagePack objects to an io.Writer.
// You must call *Writer.Flush() in order
// to flush all of the buffered data
// to the underlying writer.
type Writer struct {
w io.Writer
buf []byte
wloc int
}
// NewWriter returns a new *Writer.
func NewWriter(w io.Writer) *Writer {
if wr, ok := w.(*Writer); ok {
return wr
}
return popWriter(w)
}
// NewWriterSize returns a writer with a custom buffer size.
func NewWriterSize(w io.Writer, sz int) *Writer {
// we must be able to require() 18
// contiguous bytes, so that is the
// practical minimum buffer size
if sz < 18 {
sz = 18
}
return &Writer{
w: w,
buf: make([]byte, sz),
}
}
// Encode encodes an Encodable to an io.Writer.
func Encode(w io.Writer, e Encodable) error {
wr := NewWriter(w)
err := e.EncodeMsg(wr)
if err == nil {
err = wr.Flush()
}
freeW(wr)
return err
}
func (mw *Writer) flush() error {
if mw.wloc == 0 {
return nil
}
n, err := mw.w.Write(mw.buf[:mw.wloc])
if err != nil {
if n > 0 {
mw.wloc = copy(mw.buf, mw.buf[n:mw.wloc])
}
return err
}
mw.wloc = 0
return nil
}
// Flush flushes all of the buffered
// data to the underlying writer.
func (mw *Writer) Flush() error { return mw.flush() }
// Buffered returns the number bytes in the write buffer
func (mw *Writer) Buffered() int { return len(mw.buf) - mw.wloc }
func (mw *Writer) avail() int { return len(mw.buf) - mw.wloc }
func (mw *Writer) bufsize() int { return len(mw.buf) }
// NOTE: this should only be called with
// a number that is guaranteed to be less than
// len(mw.buf). typically, it is called with a constant.
//
// NOTE: this is a hot code path
func (mw *Writer) require(n int) (int, error) {
c := len(mw.buf)
wl := mw.wloc
if c-wl < n {
if err := mw.flush(); err != nil {
return 0, err
}
wl = mw.wloc
}
mw.wloc += n
return wl, nil
}
func (mw *Writer) Append(b ...byte) error {
if mw.avail() < len(b) {
err := mw.flush()
if err != nil {
return err
}
}
mw.wloc += copy(mw.buf[mw.wloc:], b)
return nil
}
// push one byte onto the buffer
//
// NOTE: this is a hot code path
func (mw *Writer) push(b byte) error {
if mw.wloc == len(mw.buf) {
if err := mw.flush(); err != nil {
return err
}
}
mw.buf[mw.wloc] = b
mw.wloc++
return nil
}
func (mw *Writer) prefix8(b byte, u uint8) error {
const need = 2
if len(mw.buf)-mw.wloc < need {
if err := mw.flush(); err != nil {
return err
}
}
prefixu8(mw.buf[mw.wloc:], b, u)
mw.wloc += need
return nil
}
func (mw *Writer) prefix16(b byte, u uint16) error {
const need = 3
if len(mw.buf)-mw.wloc < need {
if err := mw.flush(); err != nil {
return err
}
}
prefixu16(mw.buf[mw.wloc:], b, u)
mw.wloc += need
return nil
}
func (mw *Writer) prefix32(b byte, u uint32) error {
const need = 5
if len(mw.buf)-mw.wloc < need {
if err := mw.flush(); err != nil {
return err
}
}
prefixu32(mw.buf[mw.wloc:], b, u)
mw.wloc += need
return nil
}
func (mw *Writer) prefix64(b byte, u uint64) error {
const need = 9
if len(mw.buf)-mw.wloc < need {
if err := mw.flush(); err != nil {
return err
}
}
prefixu64(mw.buf[mw.wloc:], b, u)
mw.wloc += need
return nil
}
// Write implements io.Writer, and writes
// data directly to the buffer.
func (mw *Writer) Write(p []byte) (int, error) {
l := len(p)
if mw.avail() < l {
if err := mw.flush(); err != nil {
return 0, err
}
if l > len(mw.buf) {
return mw.w.Write(p)
}
}
mw.wloc += copy(mw.buf[mw.wloc:], p)
return l, nil
}
// implements io.WriteString
func (mw *Writer) writeString(s string) error {
l := len(s)
if mw.avail() < l {
if err := mw.flush(); err != nil {
return err
}
if l > len(mw.buf) {
_, err := io.WriteString(mw.w, s)
return err
}
}
mw.wloc += copy(mw.buf[mw.wloc:], s)
return nil
}
// Reset changes the underlying writer used by the Writer
func (mw *Writer) Reset(w io.Writer) {
mw.buf = mw.buf[:cap(mw.buf)]
mw.w = w
mw.wloc = 0
}
// WriteMapHeader writes a map header of the given
// size to the writer
func (mw *Writer) WriteMapHeader(sz uint32) error {
switch {
case sz <= 15:
return mw.push(wfixmap(uint8(sz)))
case sz <= math.MaxUint16:
return mw.prefix16(mmap16, uint16(sz))
default:
return mw.prefix32(mmap32, sz)
}
}
// WriteArrayHeader writes an array header of the
// given size to the writer
func (mw *Writer) WriteArrayHeader(sz uint32) error {
switch {
case sz <= 15:
return mw.push(wfixarray(uint8(sz)))
case sz <= math.MaxUint16:
return mw.prefix16(marray16, uint16(sz))
default:
return mw.prefix32(marray32, sz)
}
}
// WriteNil writes a nil byte to the buffer
func (mw *Writer) WriteNil() error {
return mw.push(mnil)
}
// WriteFloat64 writes a float64 to the writer
func (mw *Writer) WriteFloat64(f float64) error {
return mw.prefix64(mfloat64, math.Float64bits(f))
}
// WriteFloat32 writes a float32 to the writer
func (mw *Writer) WriteFloat32(f float32) error {
return mw.prefix32(mfloat32, math.Float32bits(f))
}
// WriteInt64 writes an int64 to the writer
func (mw *Writer) WriteInt64(i int64) error {
if i >= 0 {
switch {
case i <= math.MaxInt8:
return mw.push(wfixint(uint8(i)))
case i <= math.MaxInt16:
return mw.prefix16(mint16, uint16(i))
case i <= math.MaxInt32:
return mw.prefix32(mint32, uint32(i))
default:
return mw.prefix64(mint64, uint64(i))
}
}
switch {
case i >= -32:
return mw.push(wnfixint(int8(i)))
case i >= math.MinInt8:
return mw.prefix8(mint8, uint8(i))
case i >= math.MinInt16:
return mw.prefix16(mint16, uint16(i))
case i >= math.MinInt32:
return mw.prefix32(mint32, uint32(i))
default:
return mw.prefix64(mint64, uint64(i))
}
}
// WriteInt8 writes an int8 to the writer
func (mw *Writer) WriteInt8(i int8) error { return mw.WriteInt64(int64(i)) }
// WriteInt16 writes an int16 to the writer
func (mw *Writer) WriteInt16(i int16) error { return mw.WriteInt64(int64(i)) }
// WriteInt32 writes an int32 to the writer
func (mw *Writer) WriteInt32(i int32) error { return mw.WriteInt64(int64(i)) }
// WriteInt writes an int to the writer
func (mw *Writer) WriteInt(i int) error { return mw.WriteInt64(int64(i)) }
// WriteUint64 writes a uint64 to the writer
func (mw *Writer) WriteUint64(u uint64) error {
switch {
case u <= (1<<7)-1:
return mw.push(wfixint(uint8(u)))
case u <= math.MaxUint8:
return mw.prefix8(muint8, uint8(u))
case u <= math.MaxUint16:
return mw.prefix16(muint16, uint16(u))
case u <= math.MaxUint32:
return mw.prefix32(muint32, uint32(u))
default:
return mw.prefix64(muint64, u)
}
}
// WriteByte is analogous to WriteUint8
func (mw *Writer) WriteByte(u byte) error { return mw.WriteUint8(uint8(u)) }
// WriteUint8 writes a uint8 to the writer
func (mw *Writer) WriteUint8(u uint8) error { return mw.WriteUint64(uint64(u)) }
// WriteUint16 writes a uint16 to the writer
func (mw *Writer) WriteUint16(u uint16) error { return mw.WriteUint64(uint64(u)) }
// WriteUint32 writes a uint32 to the writer
func (mw *Writer) WriteUint32(u uint32) error { return mw.WriteUint64(uint64(u)) }
// WriteUint writes a uint to the writer
func (mw *Writer) WriteUint(u uint) error { return mw.WriteUint64(uint64(u)) }
// WriteBytes writes binary as 'bin' to the writer
func (mw *Writer) WriteBytes(b []byte) error {
sz := uint32(len(b))
var err error
switch {
case sz <= math.MaxUint8:
err = mw.prefix8(mbin8, uint8(sz))
case sz <= math.MaxUint16:
err = mw.prefix16(mbin16, uint16(sz))
default:
err = mw.prefix32(mbin32, sz)
}
if err != nil {
return err
}
_, err = mw.Write(b)
return err
}
// WriteBytesHeader writes just the size header
// of a MessagePack 'bin' object. The user is responsible
// for then writing 'sz' more bytes into the stream.
func (mw *Writer) WriteBytesHeader(sz uint32) error {
switch {
case sz <= math.MaxUint8:
return mw.prefix8(mbin8, uint8(sz))
case sz <= math.MaxUint16:
return mw.prefix16(mbin16, uint16(sz))
default:
return mw.prefix32(mbin32, sz)
}
}
// WriteBool writes a bool to the writer
func (mw *Writer) WriteBool(b bool) error {
if b {
return mw.push(mtrue)
}
return mw.push(mfalse)
}
// WriteString writes a messagepack string to the writer.
// (This is NOT an implementation of io.StringWriter)
func (mw *Writer) WriteString(s string) error {
sz := uint32(len(s))
var err error
switch {
case sz <= 31:
err = mw.push(wfixstr(uint8(sz)))
case sz <= math.MaxUint8:
err = mw.prefix8(mstr8, uint8(sz))
case sz <= math.MaxUint16:
err = mw.prefix16(mstr16, uint16(sz))
default:
err = mw.prefix32(mstr32, sz)
}
if err != nil {
return err
}
return mw.writeString(s)
}
// WriteStringHeader writes just the string size
// header of a MessagePack 'str' object. The user
// is responsible for writing 'sz' more valid UTF-8
// bytes to the stream.
func (mw *Writer) WriteStringHeader(sz uint32) error {
switch {
case sz <= 31:
return mw.push(wfixstr(uint8(sz)))
case sz <= math.MaxUint8:
return mw.prefix8(mstr8, uint8(sz))
case sz <= math.MaxUint16:
return mw.prefix16(mstr16, uint16(sz))
default:
return mw.prefix32(mstr32, sz)
}
}
// WriteStringFromBytes writes a 'str' object
// from a []byte.
func (mw *Writer) WriteStringFromBytes(str []byte) error {
sz := uint32(len(str))
var err error
switch {
case sz <= 31:
err = mw.push(wfixstr(uint8(sz)))
case sz <= math.MaxUint8:
err = mw.prefix8(mstr8, uint8(sz))
case sz <= math.MaxUint16:
err = mw.prefix16(mstr16, uint16(sz))
default:
err = mw.prefix32(mstr32, sz)
}
if err != nil {
return err
}
_, err = mw.Write(str)
return err
}
// WriteComplex64 writes a complex64 to the writer
func (mw *Writer) WriteComplex64(f complex64) error {
o, err := mw.require(10)
if err != nil {
return err
}
mw.buf[o] = mfixext8
mw.buf[o+1] = Complex64Extension
big.PutUint32(mw.buf[o+2:], math.Float32bits(real(f)))
big.PutUint32(mw.buf[o+6:], math.Float32bits(imag(f)))
return nil
}
// WriteComplex128 writes a complex128 to the writer
func (mw *Writer) WriteComplex128(f complex128) error {
o, err := mw.require(18)
if err != nil {
return err
}
mw.buf[o] = mfixext16
mw.buf[o+1] = Complex128Extension
big.PutUint64(mw.buf[o+2:], math.Float64bits(real(f)))
big.PutUint64(mw.buf[o+10:], math.Float64bits(imag(f)))
return nil
}
// WriteMapStrStr writes a map[string]string to the writer
func (mw *Writer) WriteMapStrStr(mp map[string]string) (err error) {
err = mw.WriteMapHeader(uint32(len(mp)))
if err != nil {
return
}
for key, val := range mp {
err = mw.WriteString(key)
if err != nil {
return
}
err = mw.WriteString(val)
if err != nil {
return
}
}
return nil
}
// WriteMapStrIntf writes a map[string]interface to the writer
func (mw *Writer) WriteMapStrIntf(mp map[string]interface{}) (err error) {
err = mw.WriteMapHeader(uint32(len(mp)))
if err != nil {
return
}
for key, val := range mp {
err = mw.WriteString(key)
if err != nil {
return
}
err = mw.WriteIntf(val)
if err != nil {
return
}
}
return
}
// WriteTime writes a time.Time object to the wire.
//
// Time is encoded as Unix time, which means that
// location (time zone) data is removed from the object.
// The encoded object itself is 12 bytes: 8 bytes for
// a big-endian 64-bit integer denoting seconds
// elapsed since "zero" Unix time, followed by 4 bytes
// for a big-endian 32-bit signed integer denoting
// the nanosecond offset of the time. This encoding
// is intended to ease portability across languages.
// (Note that this is *not* the standard time.Time
// binary encoding, because its implementation relies
// heavily on the internal representation used by the
// time package.)
func (mw *Writer) WriteTime(t time.Time) error {
t = t.UTC()
o, err := mw.require(15)
if err != nil {
return err
}
mw.buf[o] = mext8
mw.buf[o+1] = 12
mw.buf[o+2] = TimeExtension
putUnix(mw.buf[o+3:], t.Unix(), int32(t.Nanosecond()))
return nil
}
// WriteIntf writes the concrete type of 'v'.
// WriteIntf will error if 'v' is not one of the following:
// - A bool, float, string, []byte, int, uint, or complex
// - A map of supported types (with string keys)
// - An array or slice of supported types
// - A pointer to a supported type
// - A type that satisfies the msgp.Encodable interface
// - A type that satisfies the msgp.Extension interface
func (mw *Writer) WriteIntf(v interface{}) error {
if v == nil {
return mw.WriteNil()
}
switch v := v.(type) {
// preferred interfaces
case Encodable:
return v.EncodeMsg(mw)
case Extension:
return mw.WriteExtension(v)
// concrete types
case bool:
return mw.WriteBool(v)
case float32:
return mw.WriteFloat32(v)
case float64:
return mw.WriteFloat64(v)
case complex64:
return mw.WriteComplex64(v)
case complex128:
return mw.WriteComplex128(v)
case uint8:
return mw.WriteUint8(v)
case uint16:
return mw.WriteUint16(v)
case uint32:
return mw.WriteUint32(v)
case uint64:
return mw.WriteUint64(v)
case uint:
return mw.WriteUint(v)
case int8:
return mw.WriteInt8(v)
case int16:
return mw.WriteInt16(v)
case int32:
return mw.WriteInt32(v)
case int64:
return mw.WriteInt64(v)
case int:
return mw.WriteInt(v)
case string:
return mw.WriteString(v)
case []byte:
return mw.WriteBytes(v)
case map[string]string:
return mw.WriteMapStrStr(v)
case map[string]interface{}:
return mw.WriteMapStrIntf(v)
case time.Time:
return mw.WriteTime(v)
}
val := reflect.ValueOf(v)
if !isSupported(val.Kind()) || !val.IsValid() {
return fmt.Errorf("msgp: type %s not supported", val)
}
switch val.Kind() {
case reflect.Ptr:
if val.IsNil() {
return mw.WriteNil()
}
return mw.WriteIntf(val.Elem().Interface())
case reflect.Slice:
return mw.writeSlice(val)
case reflect.Map:
return mw.writeMap(val)
}
return &ErrUnsupportedType{val.Type()}
}
func (mw *Writer) writeMap(v reflect.Value) (err error) {
if v.Type().Key().Kind() != reflect.String {
return errors.New("msgp: map keys must be strings")
}
ks := v.MapKeys()
err = mw.WriteMapHeader(uint32(len(ks)))
if err != nil {
return
}
for _, key := range ks {
val := v.MapIndex(key)
err = mw.WriteString(key.String())
if err != nil {
return
}
err = mw.WriteIntf(val.Interface())
if err != nil {
return
}
}
return
}
func (mw *Writer) writeSlice(v reflect.Value) (err error) {
// is []byte
if v.Type().ConvertibleTo(btsType) {
return mw.WriteBytes(v.Bytes())
}
sz := uint32(v.Len())
err = mw.WriteArrayHeader(sz)
if err != nil {
return
}
for i := uint32(0); i < sz; i++ {
err = mw.WriteIntf(v.Index(int(i)).Interface())
if err != nil {
return
}
}
return
}
func (mw *Writer) writeStruct(v reflect.Value) error {
if enc, ok := v.Interface().(Encodable); ok {
return enc.EncodeMsg(mw)
}
return fmt.Errorf("msgp: unsupported type: %s", v.Type())
}
func (mw *Writer) writeVal(v reflect.Value) error {
if !isSupported(v.Kind()) {
return fmt.Errorf("msgp: msgp/enc: type %q not supported", v.Type())
}
// shortcut for nil values
if v.IsNil() {
return mw.WriteNil()
}
switch v.Kind() {
case reflect.Bool:
return mw.WriteBool(v.Bool())
case reflect.Float32, reflect.Float64:
return mw.WriteFloat64(v.Float())
case reflect.Complex64, reflect.Complex128:
return mw.WriteComplex128(v.Complex())
case reflect.Int, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Int8:
return mw.WriteInt64(v.Int())
case reflect.Interface, reflect.Ptr:
if v.IsNil() {
mw.WriteNil()
}
return mw.writeVal(v.Elem())
case reflect.Map:
return mw.writeMap(v)
case reflect.Uint, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uint8:
return mw.WriteUint64(v.Uint())
case reflect.String:
return mw.WriteString(v.String())
case reflect.Slice, reflect.Array:
return mw.writeSlice(v)
case reflect.Struct:
return mw.writeStruct(v)
}
return fmt.Errorf("msgp: msgp/enc: type %q not supported", v.Type())
}
// is the reflect.Kind encodable?
func isSupported(k reflect.Kind) bool {
switch k {
case reflect.Func, reflect.Chan, reflect.Invalid, reflect.UnsafePointer:
return false
default:
return true
}
}
// GuessSize guesses the size of the underlying
// value of 'i'. If the underlying value is not
// a simple builtin (or []byte), GuessSize defaults
// to 512.
func GuessSize(i interface{}) int {
if i == nil {
return NilSize
}
switch i := i.(type) {
case Sizer:
return i.Msgsize()
case Extension:
return ExtensionPrefixSize + i.Len()
case float64:
return Float64Size
case float32:
return Float32Size
case uint8, uint16, uint32, uint64, uint:
return UintSize
case int8, int16, int32, int64, int:
return IntSize
case []byte:
return BytesPrefixSize + len(i)
case string:
return StringPrefixSize + len(i)
case complex64:
return Complex64Size
case complex128:
return Complex128Size
case bool:
return BoolSize
case map[string]interface{}:
s := MapHeaderSize
for key, val := range i {
s += StringPrefixSize + len(key) + GuessSize(val)
}
return s
case map[string]string:
s := MapHeaderSize
for key, val := range i {
s += 2*StringPrefixSize + len(key) + len(val)
}
return s
default:
return 512
}
}