forkjo/vendor/github.com/tinylib/msgp/msgp/read_bytes.go
2018-05-19 20:49:46 +08:00

1197 lines
23 KiB
Go

package msgp
import (
"bytes"
"encoding/binary"
"math"
"time"
)
var big = binary.BigEndian
// NextType returns the type of the next
// object in the slice. If the length
// of the input is zero, it returns
// InvalidType.
func NextType(b []byte) Type {
if len(b) == 0 {
return InvalidType
}
spec := sizes[b[0]]
t := spec.typ
if t == ExtensionType && len(b) > int(spec.size) {
var tp int8
if spec.extra == constsize {
tp = int8(b[1])
} else {
tp = int8(b[spec.size-1])
}
switch tp {
case TimeExtension:
return TimeType
case Complex128Extension:
return Complex128Type
case Complex64Extension:
return Complex64Type
default:
return ExtensionType
}
}
return t
}
// IsNil returns true if len(b)>0 and
// the leading byte is a 'nil' MessagePack
// byte; false otherwise
func IsNil(b []byte) bool {
if len(b) != 0 && b[0] == mnil {
return true
}
return false
}
// Raw is raw MessagePack.
// Raw allows you to read and write
// data without interpreting its contents.
type Raw []byte
// MarshalMsg implements msgp.Marshaler.
// It appends the raw contents of 'raw'
// to the provided byte slice. If 'raw'
// is 0 bytes, 'nil' will be appended instead.
func (r Raw) MarshalMsg(b []byte) ([]byte, error) {
i := len(r)
if i == 0 {
return AppendNil(b), nil
}
o, l := ensure(b, i)
copy(o[l:], []byte(r))
return o, nil
}
// UnmarshalMsg implements msgp.Unmarshaler.
// It sets the contents of *Raw to be the next
// object in the provided byte slice.
func (r *Raw) UnmarshalMsg(b []byte) ([]byte, error) {
l := len(b)
out, err := Skip(b)
if err != nil {
return b, err
}
rlen := l - len(out)
if IsNil(b[:rlen]) {
rlen = 0
}
if cap(*r) < rlen {
*r = make(Raw, rlen)
} else {
*r = (*r)[0:rlen]
}
copy(*r, b[:rlen])
return out, nil
}
// EncodeMsg implements msgp.Encodable.
// It writes the raw bytes to the writer.
// If r is empty, it writes 'nil' instead.
func (r Raw) EncodeMsg(w *Writer) error {
if len(r) == 0 {
return w.WriteNil()
}
_, err := w.Write([]byte(r))
return err
}
// DecodeMsg implements msgp.Decodable.
// It sets the value of *Raw to be the
// next object on the wire.
func (r *Raw) DecodeMsg(f *Reader) error {
*r = (*r)[:0]
err := appendNext(f, (*[]byte)(r))
if IsNil(*r) {
*r = (*r)[:0]
}
return err
}
// Msgsize implements msgp.Sizer
func (r Raw) Msgsize() int {
l := len(r)
if l == 0 {
return 1 // for 'nil'
}
return l
}
func appendNext(f *Reader, d *[]byte) error {
amt, o, err := getNextSize(f.R)
if err != nil {
return err
}
var i int
*d, i = ensure(*d, int(amt))
_, err = f.R.ReadFull((*d)[i:])
if err != nil {
return err
}
for o > 0 {
err = appendNext(f, d)
if err != nil {
return err
}
o--
}
return nil
}
// MarshalJSON implements json.Marshaler
func (r *Raw) MarshalJSON() ([]byte, error) {
var buf bytes.Buffer
_, err := UnmarshalAsJSON(&buf, []byte(*r))
return buf.Bytes(), err
}
// ReadMapHeaderBytes reads a map header size
// from 'b' and returns the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a map)
func ReadMapHeaderBytes(b []byte) (sz uint32, o []byte, err error) {
l := len(b)
if l < 1 {
err = ErrShortBytes
return
}
lead := b[0]
if isfixmap(lead) {
sz = uint32(rfixmap(lead))
o = b[1:]
return
}
switch lead {
case mmap16:
if l < 3 {
err = ErrShortBytes
return
}
sz = uint32(big.Uint16(b[1:]))
o = b[3:]
return
case mmap32:
if l < 5 {
err = ErrShortBytes
return
}
sz = big.Uint32(b[1:])
o = b[5:]
return
default:
err = badPrefix(MapType, lead)
return
}
}
// ReadMapKeyZC attempts to read a map key
// from 'b' and returns the key bytes and the remaining bytes
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a str or bin)
func ReadMapKeyZC(b []byte) ([]byte, []byte, error) {
o, b, err := ReadStringZC(b)
if err != nil {
if tperr, ok := err.(TypeError); ok && tperr.Encoded == BinType {
return ReadBytesZC(b)
}
return nil, b, err
}
return o, b, nil
}
// ReadArrayHeaderBytes attempts to read
// the array header size off of 'b' and return
// the size and remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not an array)
func ReadArrayHeaderBytes(b []byte) (sz uint32, o []byte, err error) {
if len(b) < 1 {
return 0, nil, ErrShortBytes
}
lead := b[0]
if isfixarray(lead) {
sz = uint32(rfixarray(lead))
o = b[1:]
return
}
switch lead {
case marray16:
if len(b) < 3 {
err = ErrShortBytes
return
}
sz = uint32(big.Uint16(b[1:]))
o = b[3:]
return
case marray32:
if len(b) < 5 {
err = ErrShortBytes
return
}
sz = big.Uint32(b[1:])
o = b[5:]
return
default:
err = badPrefix(ArrayType, lead)
return
}
}
// ReadNilBytes tries to read a "nil" byte
// off of 'b' and return the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a 'nil')
// - InvalidPrefixError
func ReadNilBytes(b []byte) ([]byte, error) {
if len(b) < 1 {
return nil, ErrShortBytes
}
if b[0] != mnil {
return b, badPrefix(NilType, b[0])
}
return b[1:], nil
}
// ReadFloat64Bytes tries to read a float64
// from 'b' and return the value and the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a float64)
func ReadFloat64Bytes(b []byte) (f float64, o []byte, err error) {
if len(b) < 9 {
if len(b) >= 5 && b[0] == mfloat32 {
var tf float32
tf, o, err = ReadFloat32Bytes(b)
f = float64(tf)
return
}
err = ErrShortBytes
return
}
if b[0] != mfloat64 {
if b[0] == mfloat32 {
var tf float32
tf, o, err = ReadFloat32Bytes(b)
f = float64(tf)
return
}
err = badPrefix(Float64Type, b[0])
return
}
f = math.Float64frombits(getMuint64(b))
o = b[9:]
return
}
// ReadFloat32Bytes tries to read a float64
// from 'b' and return the value and the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a float32)
func ReadFloat32Bytes(b []byte) (f float32, o []byte, err error) {
if len(b) < 5 {
err = ErrShortBytes
return
}
if b[0] != mfloat32 {
err = TypeError{Method: Float32Type, Encoded: getType(b[0])}
return
}
f = math.Float32frombits(getMuint32(b))
o = b[5:]
return
}
// ReadBoolBytes tries to read a float64
// from 'b' and return the value and the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a bool)
func ReadBoolBytes(b []byte) (bool, []byte, error) {
if len(b) < 1 {
return false, b, ErrShortBytes
}
switch b[0] {
case mtrue:
return true, b[1:], nil
case mfalse:
return false, b[1:], nil
default:
return false, b, badPrefix(BoolType, b[0])
}
}
// ReadInt64Bytes tries to read an int64
// from 'b' and return the value and the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError (not a int)
func ReadInt64Bytes(b []byte) (i int64, o []byte, err error) {
l := len(b)
if l < 1 {
return 0, nil, ErrShortBytes
}
lead := b[0]
if isfixint(lead) {
i = int64(rfixint(lead))
o = b[1:]
return
}
if isnfixint(lead) {
i = int64(rnfixint(lead))
o = b[1:]
return
}
switch lead {
case mint8:
if l < 2 {
err = ErrShortBytes
return
}
i = int64(getMint8(b))
o = b[2:]
return
case muint8:
if l < 2 {
err = ErrShortBytes
return
}
i = int64(getMuint8(b))
o = b[2:]
return
case mint16:
if l < 3 {
err = ErrShortBytes
return
}
i = int64(getMint16(b))
o = b[3:]
return
case muint16:
if l < 3 {
err = ErrShortBytes
return
}
i = int64(getMuint16(b))
o = b[3:]
return
case mint32:
if l < 5 {
err = ErrShortBytes
return
}
i = int64(getMint32(b))
o = b[5:]
return
case muint32:
if l < 5 {
err = ErrShortBytes
return
}
i = int64(getMuint32(b))
o = b[5:]
return
case mint64:
if l < 9 {
err = ErrShortBytes
return
}
i = int64(getMint64(b))
o = b[9:]
return
case muint64:
if l < 9 {
err = ErrShortBytes
return
}
u := getMuint64(b)
if u > math.MaxInt64 {
err = UintOverflow{Value: u, FailedBitsize: 64}
return
}
i = int64(u)
o = b[9:]
return
default:
err = badPrefix(IntType, lead)
return
}
}
// ReadInt32Bytes tries to read an int32
// from 'b' and return the value and the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a int)
// - IntOverflow{} (value doesn't fit in int32)
func ReadInt32Bytes(b []byte) (int32, []byte, error) {
i, o, err := ReadInt64Bytes(b)
if i > math.MaxInt32 || i < math.MinInt32 {
return 0, o, IntOverflow{Value: i, FailedBitsize: 32}
}
return int32(i), o, err
}
// ReadInt16Bytes tries to read an int16
// from 'b' and return the value and the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a int)
// - IntOverflow{} (value doesn't fit in int16)
func ReadInt16Bytes(b []byte) (int16, []byte, error) {
i, o, err := ReadInt64Bytes(b)
if i > math.MaxInt16 || i < math.MinInt16 {
return 0, o, IntOverflow{Value: i, FailedBitsize: 16}
}
return int16(i), o, err
}
// ReadInt8Bytes tries to read an int16
// from 'b' and return the value and the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a int)
// - IntOverflow{} (value doesn't fit in int8)
func ReadInt8Bytes(b []byte) (int8, []byte, error) {
i, o, err := ReadInt64Bytes(b)
if i > math.MaxInt8 || i < math.MinInt8 {
return 0, o, IntOverflow{Value: i, FailedBitsize: 8}
}
return int8(i), o, err
}
// ReadIntBytes tries to read an int
// from 'b' and return the value and the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a int)
// - IntOverflow{} (value doesn't fit in int; 32-bit platforms only)
func ReadIntBytes(b []byte) (int, []byte, error) {
if smallint {
i, b, err := ReadInt32Bytes(b)
return int(i), b, err
}
i, b, err := ReadInt64Bytes(b)
return int(i), b, err
}
// ReadUint64Bytes tries to read a uint64
// from 'b' and return the value and the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a uint)
func ReadUint64Bytes(b []byte) (u uint64, o []byte, err error) {
l := len(b)
if l < 1 {
return 0, nil, ErrShortBytes
}
lead := b[0]
if isfixint(lead) {
u = uint64(rfixint(lead))
o = b[1:]
return
}
switch lead {
case mint8:
if l < 2 {
err = ErrShortBytes
return
}
v := int64(getMint8(b))
if v < 0 {
err = UintBelowZero{Value: v}
return
}
u = uint64(v)
o = b[2:]
return
case muint8:
if l < 2 {
err = ErrShortBytes
return
}
u = uint64(getMuint8(b))
o = b[2:]
return
case mint16:
if l < 3 {
err = ErrShortBytes
return
}
v := int64(getMint16(b))
if v < 0 {
err = UintBelowZero{Value: v}
return
}
u = uint64(v)
o = b[3:]
return
case muint16:
if l < 3 {
err = ErrShortBytes
return
}
u = uint64(getMuint16(b))
o = b[3:]
return
case mint32:
if l < 5 {
err = ErrShortBytes
return
}
v := int64(getMint32(b))
if v < 0 {
err = UintBelowZero{Value: v}
return
}
u = uint64(v)
o = b[5:]
return
case muint32:
if l < 5 {
err = ErrShortBytes
return
}
u = uint64(getMuint32(b))
o = b[5:]
return
case mint64:
if l < 9 {
err = ErrShortBytes
return
}
v := int64(getMint64(b))
if v < 0 {
err = UintBelowZero{Value: v}
return
}
u = uint64(v)
o = b[9:]
return
case muint64:
if l < 9 {
err = ErrShortBytes
return
}
u = getMuint64(b)
o = b[9:]
return
default:
if isnfixint(lead) {
err = UintBelowZero{Value: int64(rnfixint(lead))}
} else {
err = badPrefix(UintType, lead)
}
return
}
}
// ReadUint32Bytes tries to read a uint32
// from 'b' and return the value and the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a uint)
// - UintOverflow{} (value too large for uint32)
func ReadUint32Bytes(b []byte) (uint32, []byte, error) {
v, o, err := ReadUint64Bytes(b)
if v > math.MaxUint32 {
return 0, nil, UintOverflow{Value: v, FailedBitsize: 32}
}
return uint32(v), o, err
}
// ReadUint16Bytes tries to read a uint16
// from 'b' and return the value and the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a uint)
// - UintOverflow{} (value too large for uint16)
func ReadUint16Bytes(b []byte) (uint16, []byte, error) {
v, o, err := ReadUint64Bytes(b)
if v > math.MaxUint16 {
return 0, nil, UintOverflow{Value: v, FailedBitsize: 16}
}
return uint16(v), o, err
}
// ReadUint8Bytes tries to read a uint8
// from 'b' and return the value and the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a uint)
// - UintOverflow{} (value too large for uint8)
func ReadUint8Bytes(b []byte) (uint8, []byte, error) {
v, o, err := ReadUint64Bytes(b)
if v > math.MaxUint8 {
return 0, nil, UintOverflow{Value: v, FailedBitsize: 8}
}
return uint8(v), o, err
}
// ReadUintBytes tries to read a uint
// from 'b' and return the value and the remaining bytes.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a uint)
// - UintOverflow{} (value too large for uint; 32-bit platforms only)
func ReadUintBytes(b []byte) (uint, []byte, error) {
if smallint {
u, b, err := ReadUint32Bytes(b)
return uint(u), b, err
}
u, b, err := ReadUint64Bytes(b)
return uint(u), b, err
}
// ReadByteBytes is analogous to ReadUint8Bytes
func ReadByteBytes(b []byte) (byte, []byte, error) {
return ReadUint8Bytes(b)
}
// ReadBytesBytes reads a 'bin' object
// from 'b' and returns its vaue and
// the remaining bytes in 'b'.
// Possible errors:
// - ErrShortBytes (too few bytes)
// - TypeError{} (not a 'bin' object)
func ReadBytesBytes(b []byte, scratch []byte) (v []byte, o []byte, err error) {
return readBytesBytes(b, scratch, false)
}
func readBytesBytes(b []byte, scratch []byte, zc bool) (v []byte, o []byte, err error) {
l := len(b)
if l < 1 {
return nil, nil, ErrShortBytes
}
lead := b[0]
var read int
switch lead {
case mbin8:
if l < 2 {
err = ErrShortBytes
return
}
read = int(b[1])
b = b[2:]
case mbin16:
if l < 3 {
err = ErrShortBytes
return
}
read = int(big.Uint16(b[1:]))
b = b[3:]
case mbin32:
if l < 5 {
err = ErrShortBytes
return
}
read = int(big.Uint32(b[1:]))
b = b[5:]
default:
err = badPrefix(BinType, lead)
return
}
if len(b) < read {
err = ErrShortBytes
return
}
// zero-copy
if zc {
v = b[0:read]
o = b[read:]
return
}
if cap(scratch) >= read {
v = scratch[0:read]
} else {
v = make([]byte, read)
}
o = b[copy(v, b):]
return
}
// ReadBytesZC extracts the messagepack-encoded
// binary field without copying. The returned []byte
// points to the same memory as the input slice.
// Possible errors:
// - ErrShortBytes (b not long enough)
// - TypeError{} (object not 'bin')
func ReadBytesZC(b []byte) (v []byte, o []byte, err error) {
return readBytesBytes(b, nil, true)
}
func ReadExactBytes(b []byte, into []byte) (o []byte, err error) {
l := len(b)
if l < 1 {
err = ErrShortBytes
return
}
lead := b[0]
var read uint32
var skip int
switch lead {
case mbin8:
if l < 2 {
err = ErrShortBytes
return
}
read = uint32(b[1])
skip = 2
case mbin16:
if l < 3 {
err = ErrShortBytes
return
}
read = uint32(big.Uint16(b[1:]))
skip = 3
case mbin32:
if l < 5 {
err = ErrShortBytes
return
}
read = uint32(big.Uint32(b[1:]))
skip = 5
default:
err = badPrefix(BinType, lead)
return
}
if read != uint32(len(into)) {
err = ArrayError{Wanted: uint32(len(into)), Got: read}
return
}
o = b[skip+copy(into, b[skip:]):]
return
}
// ReadStringZC reads a messagepack string field
// without copying. The returned []byte points
// to the same memory as the input slice.
// Possible errors:
// - ErrShortBytes (b not long enough)
// - TypeError{} (object not 'str')
func ReadStringZC(b []byte) (v []byte, o []byte, err error) {
l := len(b)
if l < 1 {
return nil, nil, ErrShortBytes
}
lead := b[0]
var read int
if isfixstr(lead) {
read = int(rfixstr(lead))
b = b[1:]
} else {
switch lead {
case mstr8:
if l < 2 {
err = ErrShortBytes
return
}
read = int(b[1])
b = b[2:]
case mstr16:
if l < 3 {
err = ErrShortBytes
return
}
read = int(big.Uint16(b[1:]))
b = b[3:]
case mstr32:
if l < 5 {
err = ErrShortBytes
return
}
read = int(big.Uint32(b[1:]))
b = b[5:]
default:
err = TypeError{Method: StrType, Encoded: getType(lead)}
return
}
}
if len(b) < read {
err = ErrShortBytes
return
}
v = b[0:read]
o = b[read:]
return
}
// ReadStringBytes reads a 'str' object
// from 'b' and returns its value and the
// remaining bytes in 'b'.
// Possible errors:
// - ErrShortBytes (b not long enough)
// - TypeError{} (not 'str' type)
// - InvalidPrefixError
func ReadStringBytes(b []byte) (string, []byte, error) {
v, o, err := ReadStringZC(b)
return string(v), o, err
}
// ReadStringAsBytes reads a 'str' object
// into a slice of bytes. 'v' is the value of
// the 'str' object, which may reside in memory
// pointed to by 'scratch.' 'o' is the remaining bytes
// in 'b.''
// Possible errors:
// - ErrShortBytes (b not long enough)
// - TypeError{} (not 'str' type)
// - InvalidPrefixError (unknown type marker)
func ReadStringAsBytes(b []byte, scratch []byte) (v []byte, o []byte, err error) {
var tmp []byte
tmp, o, err = ReadStringZC(b)
v = append(scratch[:0], tmp...)
return
}
// ReadComplex128Bytes reads a complex128
// extension object from 'b' and returns the
// remaining bytes.
// Possible errors:
// - ErrShortBytes (not enough bytes in 'b')
// - TypeError{} (object not a complex128)
// - InvalidPrefixError
// - ExtensionTypeError{} (object an extension of the correct size, but not a complex128)
func ReadComplex128Bytes(b []byte) (c complex128, o []byte, err error) {
if len(b) < 18 {
err = ErrShortBytes
return
}
if b[0] != mfixext16 {
err = badPrefix(Complex128Type, b[0])
return
}
if int8(b[1]) != Complex128Extension {
err = errExt(int8(b[1]), Complex128Extension)
return
}
c = complex(math.Float64frombits(big.Uint64(b[2:])),
math.Float64frombits(big.Uint64(b[10:])))
o = b[18:]
return
}
// ReadComplex64Bytes reads a complex64
// extension object from 'b' and returns the
// remaining bytes.
// Possible errors:
// - ErrShortBytes (not enough bytes in 'b')
// - TypeError{} (object not a complex64)
// - ExtensionTypeError{} (object an extension of the correct size, but not a complex64)
func ReadComplex64Bytes(b []byte) (c complex64, o []byte, err error) {
if len(b) < 10 {
err = ErrShortBytes
return
}
if b[0] != mfixext8 {
err = badPrefix(Complex64Type, b[0])
return
}
if b[1] != Complex64Extension {
err = errExt(int8(b[1]), Complex64Extension)
return
}
c = complex(math.Float32frombits(big.Uint32(b[2:])),
math.Float32frombits(big.Uint32(b[6:])))
o = b[10:]
return
}
// ReadTimeBytes reads a time.Time
// extension object from 'b' and returns the
// remaining bytes.
// Possible errors:
// - ErrShortBytes (not enough bytes in 'b')
// - TypeError{} (object not a complex64)
// - ExtensionTypeError{} (object an extension of the correct size, but not a time.Time)
func ReadTimeBytes(b []byte) (t time.Time, o []byte, err error) {
if len(b) < 15 {
err = ErrShortBytes
return
}
if b[0] != mext8 || b[1] != 12 {
err = badPrefix(TimeType, b[0])
return
}
if int8(b[2]) != TimeExtension {
err = errExt(int8(b[2]), TimeExtension)
return
}
sec, nsec := getUnix(b[3:])
t = time.Unix(sec, int64(nsec)).Local()
o = b[15:]
return
}
// ReadMapStrIntfBytes reads a map[string]interface{}
// out of 'b' and returns the map and remaining bytes.
// If 'old' is non-nil, the values will be read into that map.
func ReadMapStrIntfBytes(b []byte, old map[string]interface{}) (v map[string]interface{}, o []byte, err error) {
var sz uint32
o = b
sz, o, err = ReadMapHeaderBytes(o)
if err != nil {
return
}
if old != nil {
for key := range old {
delete(old, key)
}
v = old
} else {
v = make(map[string]interface{}, int(sz))
}
for z := uint32(0); z < sz; z++ {
if len(o) < 1 {
err = ErrShortBytes
return
}
var key []byte
key, o, err = ReadMapKeyZC(o)
if err != nil {
return
}
var val interface{}
val, o, err = ReadIntfBytes(o)
if err != nil {
return
}
v[string(key)] = val
}
return
}
// ReadIntfBytes attempts to read
// the next object out of 'b' as a raw interface{} and
// return the remaining bytes.
func ReadIntfBytes(b []byte) (i interface{}, o []byte, err error) {
if len(b) < 1 {
err = ErrShortBytes
return
}
k := NextType(b)
switch k {
case MapType:
i, o, err = ReadMapStrIntfBytes(b, nil)
return
case ArrayType:
var sz uint32
sz, o, err = ReadArrayHeaderBytes(b)
if err != nil {
return
}
j := make([]interface{}, int(sz))
i = j
for d := range j {
j[d], o, err = ReadIntfBytes(o)
if err != nil {
return
}
}
return
case Float32Type:
i, o, err = ReadFloat32Bytes(b)
return
case Float64Type:
i, o, err = ReadFloat64Bytes(b)
return
case IntType:
i, o, err = ReadInt64Bytes(b)
return
case UintType:
i, o, err = ReadUint64Bytes(b)
return
case BoolType:
i, o, err = ReadBoolBytes(b)
return
case TimeType:
i, o, err = ReadTimeBytes(b)
return
case Complex64Type:
i, o, err = ReadComplex64Bytes(b)
return
case Complex128Type:
i, o, err = ReadComplex128Bytes(b)
return
case ExtensionType:
var t int8
t, err = peekExtension(b)
if err != nil {
return
}
// use a user-defined extension,
// if it's been registered
f, ok := extensionReg[t]
if ok {
e := f()
o, err = ReadExtensionBytes(b, e)
i = e
return
}
// last resort is a raw extension
e := RawExtension{}
e.Type = int8(t)
o, err = ReadExtensionBytes(b, &e)
i = &e
return
case NilType:
o, err = ReadNilBytes(b)
return
case BinType:
i, o, err = ReadBytesBytes(b, nil)
return
case StrType:
i, o, err = ReadStringBytes(b)
return
default:
err = InvalidPrefixError(b[0])
return
}
}
// Skip skips the next object in 'b' and
// returns the remaining bytes. If the object
// is a map or array, all of its elements
// will be skipped.
// Possible Errors:
// - ErrShortBytes (not enough bytes in b)
// - InvalidPrefixError (bad encoding)
func Skip(b []byte) ([]byte, error) {
sz, asz, err := getSize(b)
if err != nil {
return b, err
}
if uintptr(len(b)) < sz {
return b, ErrShortBytes
}
b = b[sz:]
for asz > 0 {
b, err = Skip(b)
if err != nil {
return b, err
}
asz--
}
return b, nil
}
// returns (skip N bytes, skip M objects, error)
func getSize(b []byte) (uintptr, uintptr, error) {
l := len(b)
if l == 0 {
return 0, 0, ErrShortBytes
}
lead := b[0]
spec := &sizes[lead] // get type information
size, mode := spec.size, spec.extra
if size == 0 {
return 0, 0, InvalidPrefixError(lead)
}
if mode >= 0 { // fixed composites
return uintptr(size), uintptr(mode), nil
}
if l < int(size) {
return 0, 0, ErrShortBytes
}
switch mode {
case extra8:
return uintptr(size) + uintptr(b[1]), 0, nil
case extra16:
return uintptr(size) + uintptr(big.Uint16(b[1:])), 0, nil
case extra32:
return uintptr(size) + uintptr(big.Uint32(b[1:])), 0, nil
case map16v:
return uintptr(size), 2 * uintptr(big.Uint16(b[1:])), nil
case map32v:
return uintptr(size), 2 * uintptr(big.Uint32(b[1:])), nil
case array16v:
return uintptr(size), uintptr(big.Uint16(b[1:])), nil
case array32v:
return uintptr(size), uintptr(big.Uint32(b[1:])), nil
default:
return 0, 0, fatal
}
}