// Copyright (c) 2012, 2013 Ugorji Nwoke. All rights reserved.
// Use of this source code is governed by a BSD-style license found in the LICENSE file.
package codec
import "math"
const (
_ uint8 = iota
simpleVdNil = 1
simpleVdFalse = 2
simpleVdTrue = 3
simpleVdFloat32 = 4
simpleVdFloat64 = 5
// each lasts for 4 (ie n, n+1, n+2, n+3)
simpleVdPosInt = 8
simpleVdNegInt = 12
// containers: each lasts for 4 (ie n, n+1, n+2, ... n+7)
simpleVdString = 216
simpleVdByteArray = 224
simpleVdArray = 232
simpleVdMap = 240
simpleVdExt = 248
)
type simpleEncDriver struct {
h *SimpleHandle
w encWriter
//b [8]byte
}
func (e *simpleEncDriver) isBuiltinType(rt uintptr) bool {
return false
}
func (e *simpleEncDriver) encodeBuiltin(rt uintptr, v interface{}) {
}
func (e *simpleEncDriver) encodeNil() {
e.w.writen1(simpleVdNil)
}
func (e *simpleEncDriver) encodeBool(b bool) {
if b {
e.w.writen1(simpleVdTrue)
} else {
e.w.writen1(simpleVdFalse)
}
}
func (e *simpleEncDriver) encodeFloat32(f float32) {
e.w.writen1(simpleVdFloat32)
e.w.writeUint32(math.Float32bits(f))
}
func (e *simpleEncDriver) encodeFloat64(f float64) {
e.w.writen1(simpleVdFloat64)
e.w.writeUint64(math.Float64bits(f))
}
func (e *simpleEncDriver) encodeInt(v int64) {
if v < 0 {
e.encUint(uint64(-v), simpleVdNegInt)
} else {
e.encUint(uint64(v), simpleVdPosInt)
}
}
func (e *simpleEncDriver) encodeUint(v uint64) {
e.encUint(v, simpleVdPosInt)
}
func (e *simpleEncDriver) encUint(v uint64, bd uint8) {
switch {
case v <= math.MaxUint8:
e.w.writen2(bd, uint8(v))
case v <= math.MaxUint16:
e.w.writen1(bd + 1)
e.w.writeUint16(uint16(v))
case v <= math.MaxUint32:
e.w.writen1(bd + 2)
e.w.writeUint32(uint32(v))
case v <= math.MaxUint64:
e.w.writen1(bd + 3)
e.w.writeUint64(v)
}
}
func (e *simpleEncDriver) encLen(bd byte, length int) {
switch {
case length == 0:
e.w.writen1(bd)
case length <= math.MaxUint8:
e.w.writen1(bd + 1)
e.w.writen1(uint8(length))
case length <= math.MaxUint16:
e.w.writen1(bd + 2)
e.w.writeUint16(uint16(length))
case int64(length) <= math.MaxUint32:
e.w.writen1(bd + 3)
e.w.writeUint32(uint32(length))
default:
e.w.writen1(bd + 4)
e.w.writeUint64(uint64(length))
}
}
func (e *simpleEncDriver) encodeExtPreamble(xtag byte, length int) {
e.encLen(simpleVdExt, length)
e.w.writen1(xtag)
}
func (e *simpleEncDriver) encodeArrayPreamble(length int) {
e.encLen(simpleVdArray, length)
}
func (e *simpleEncDriver) encodeMapPreamble(length int) {
e.encLen(simpleVdMap, length)
}
func (e *simpleEncDriver) encodeString(c charEncoding, v string) {
e.encLen(simpleVdString, len(v))
e.w.writestr(v)
}
func (e *simpleEncDriver) encodeSymbol(v string) {
e.encodeString(c_UTF8, v)
}
func (e *simpleEncDriver) encodeStringBytes(c charEncoding, v []byte) {
e.encLen(simpleVdByteArray, len(v))
e.w.writeb(v)
}
//------------------------------------
type simpleDecDriver struct {
h *SimpleHandle
r decReader
bdRead bool
bdType valueType
bd byte
//b [8]byte
}
func (d *simpleDecDriver) initReadNext() {
if d.bdRead {
return
}
d.bd = d.r.readn1()
d.bdRead = true
d.bdType = valueTypeUnset
}
func (d *simpleDecDriver) currentEncodedType() valueType {
if d.bdType == valueTypeUnset {
switch d.bd {
case simpleVdNil:
d.bdType = valueTypeNil
case simpleVdTrue, simpleVdFalse:
d.bdType = valueTypeBool
case simpleVdPosInt, simpleVdPosInt + 1, simpleVdPosInt + 2, simpleVdPosInt + 3:
d.bdType = valueTypeUint
case simpleVdNegInt, simpleVdNegInt + 1, simpleVdNegInt + 2, simpleVdNegInt + 3:
d.bdType = valueTypeInt
case simpleVdFloat32, simpleVdFloat64:
d.bdType = valueTypeFloat
case simpleVdString, simpleVdString + 1, simpleVdString + 2, simpleVdString + 3, simpleVdString + 4:
d.bdType = valueTypeString
case simpleVdByteArray, simpleVdByteArray + 1, simpleVdByteArray + 2, simpleVdByteArray + 3, simpleVdByteArray + 4:
d.bdType = valueTypeBytes
case simpleVdExt, simpleVdExt + 1, simpleVdExt + 2, simpleVdExt + 3, simpleVdExt + 4:
d.bdType = valueTypeExt
case simpleVdArray, simpleVdArray + 1, simpleVdArray + 2, simpleVdArray + 3, simpleVdArray + 4:
d.bdType = valueTypeArray
case simpleVdMap, simpleVdMap + 1, simpleVdMap + 2, simpleVdMap + 3, simpleVdMap + 4:
d.bdType = valueTypeMap
default:
decErr("currentEncodedType: Unrecognized d.vd: 0x%x", d.bd)
}
}
return d.bdType
}
func (d *simpleDecDriver) tryDecodeAsNil() bool {
if d.bd == simpleVdNil {
d.bdRead = false
return true
}
return false
}
func (d *simpleDecDriver) isBuiltinType(rt uintptr) bool {
return false
}
func (d *simpleDecDriver) decodeBuiltin(rt uintptr, v interface{}) {
}
func (d *simpleDecDriver) decIntAny() (ui uint64, i int64, neg bool) {
switch d.bd {
case simpleVdPosInt:
ui = uint64(d.r.readn1())
i = int64(ui)
case simpleVdPosInt + 1:
ui = uint64(d.r.readUint16())
i = int64(ui)
case simpleVdPosInt + 2:
ui = uint64(d.r.readUint32())
i = int64(ui)
case simpleVdPosInt + 3:
ui = uint64(d.r.readUint64())
i = int64(ui)
case simpleVdNegInt:
ui = uint64(d.r.readn1())
i = -(int64(ui))
neg = true
case simpleVdNegInt + 1:
ui = uint64(d.r.readUint16())
i = -(int64(ui))
neg = true
case simpleVdNegInt + 2:
ui = uint64(d.r.readUint32())
i = -(int64(ui))
neg = true
case simpleVdNegInt + 3:
ui = uint64(d.r.readUint64())
i = -(int64(ui))
neg = true
default:
decErr("decIntAny: Integer only valid from pos/neg integer1..8. Invalid descriptor: %v", d.bd)
}
// don't do this check, because callers may only want the unsigned value.
// if ui > math.MaxInt64 {
// decErr("decIntAny: Integer out of range for signed int64: %v", ui)
// }
return
}
func (d *simpleDecDriver) decodeInt(bitsize uint8) (i int64) {
_, i, _ = d.decIntAny()
checkOverflow(0, i, bitsize)
d.bdRead = false
return
}
func (d *simpleDecDriver) decodeUint(bitsize uint8) (ui uint64) {
ui, i, neg := d.decIntAny()
if neg {
decErr("Assigning negative signed value: %v, to unsigned type", i)
}
checkOverflow(ui, 0, bitsize)
d.bdRead = false
return
}
func (d *simpleDecDriver) decodeFloat(chkOverflow32 bool) (f float64) {
switch d.bd {
case simpleVdFloat32:
f = float64(math.Float32frombits(d.r.readUint32()))
case simpleVdFloat64:
f = math.Float64frombits(d.r.readUint64())
default:
if d.bd >= simpleVdPosInt && d.bd <= simpleVdNegInt+3 {
_, i, _ := d.decIntAny()
f = float64(i)
} else {
decErr("Float only valid from float32/64: Invalid descriptor: %v", d.bd)
}
}
checkOverflowFloat32(f, chkOverflow32)
d.bdRead = false
return
}
// bool can be decoded from bool only (single byte).
func (d *simpleDecDriver) decodeBool() (b bool) {
switch d.bd {
case simpleVdTrue:
b = true
case simpleVdFalse:
default:
decErr("Invalid single-byte value for bool: %s: %x", msgBadDesc, d.bd)
}
d.bdRead = false
return
}
func (d *simpleDecDriver) readMapLen() (length int) {
d.bdRead = false
return d.decLen()
}
func (d *simpleDecDriver) readArrayLen() (length int) {
d.bdRead = false
return d.decLen()
}
func (d *simpleDecDriver) decLen() int {
switch d.bd % 8 {
case 0:
return 0
case 1:
return int(d.r.readn1())
case 2:
return int(d.r.readUint16())
case 3:
ui := uint64(d.r.readUint32())
checkOverflow(ui, 0, intBitsize)
return int(ui)
case 4:
ui := d.r.readUint64()
checkOverflow(ui, 0, intBitsize)
return int(ui)
}
decErr("decLen: Cannot read length: bd%8 must be in range 0..4. Got: %d", d.bd%8)
return -1
}
func (d *simpleDecDriver) decodeString() (s string) {
s = string(d.r.readn(d.decLen()))
d.bdRead = false
return
}
func (d *simpleDecDriver) decodeBytes(bs []byte) (bsOut []byte, changed bool) {
if clen := d.decLen(); clen > 0 {
// if no contents in stream, don't update the passed byteslice
if len(bs) != clen {
if len(bs) > clen {
bs = bs[:clen]
} else {
bs = make([]byte, clen)
}
bsOut = bs
changed = true
}
d.r.readb(bs)
}
d.bdRead = false
return
}
func (d *simpleDecDriver) decodeExt(verifyTag bool, tag byte) (xtag byte, xbs []byte) {
switch d.bd {
case simpleVdExt, simpleVdExt + 1, simpleVdExt + 2, simpleVdExt + 3, simpleVdExt + 4:
l := d.decLen()
xtag = d.r.readn1()
if verifyTag && xtag != tag {
decErr("Wrong extension tag. Got %b. Expecting: %v", xtag, tag)
}
xbs = d.r.readn(l)
case simpleVdByteArray, simpleVdByteArray + 1, simpleVdByteArray + 2, simpleVdByteArray + 3, simpleVdByteArray + 4:
xbs, _ = d.decodeBytes(nil)
default:
decErr("Invalid d.vd for extensions (Expecting extensions or byte array). Got: 0x%x", d.bd)
}
d.bdRead = false
return
}
func (d *simpleDecDriver) decodeNaked() (v interface{}, vt valueType, decodeFurther bool) {
d.initReadNext()
switch d.bd {
case simpleVdNil:
vt = valueTypeNil
case simpleVdFalse:
vt = valueTypeBool
v = false
case simpleVdTrue:
vt = valueTypeBool
v = true
case simpleVdPosInt, simpleVdPosInt + 1, simpleVdPosInt + 2, simpleVdPosInt + 3:
vt = valueTypeUint
ui, _, _ := d.decIntAny()
v = ui
case simpleVdNegInt, simpleVdNegInt + 1, simpleVdNegInt + 2, simpleVdNegInt + 3:
vt = valueTypeInt
_, i, _ := d.decIntAny()
v = i
case simpleVdFloat32:
vt = valueTypeFloat
v = d.decodeFloat(true)
case simpleVdFloat64:
vt = valueTypeFloat
v = d.decodeFloat(false)
case simpleVdString, simpleVdString + 1, simpleVdString + 2, simpleVdString + 3, simpleVdString + 4:
vt = valueTypeString
v = d.decodeString()
case simpleVdByteArray, simpleVdByteArray + 1, simpleVdByteArray + 2, simpleVdByteArray + 3, simpleVdByteArray + 4:
vt = valueTypeBytes
v, _ = d.decodeBytes(nil)
case simpleVdExt, simpleVdExt + 1, simpleVdExt + 2, simpleVdExt + 3, simpleVdExt + 4:
vt = valueTypeExt
l := d.decLen()
var re RawExt
re.Tag = d.r.readn1()
re.Data = d.r.readn(l)
v = &re
vt = valueTypeExt
case simpleVdArray, simpleVdArray + 1, simpleVdArray + 2, simpleVdArray + 3, simpleVdArray + 4:
vt = valueTypeArray
decodeFurther = true
case simpleVdMap, simpleVdMap + 1, simpleVdMap + 2, simpleVdMap + 3, simpleVdMap + 4:
vt = valueTypeMap
decodeFurther = true
default:
decErr("decodeNaked: Unrecognized d.vd: 0x%x", d.bd)
}
if !decodeFurther {
d.bdRead = false
}
return
}
//------------------------------------
// SimpleHandle is a Handle for a very simple encoding format.
//
// simple is a simplistic codec similar to binc, but not as compact.
// - Encoding of a value is always preceeded by the descriptor byte (bd)
// - True, false, nil are encoded fully in 1 byte (the descriptor)
// - Integers (intXXX, uintXXX) are encoded in 1, 2, 4 or 8 bytes (plus a descriptor byte).
// There are positive (uintXXX and intXXX >= 0) and negative (intXXX < 0) integers.
// - Floats are encoded in 4 or 8 bytes (plus a descriptor byte)
// - Lenght of containers (strings, bytes, array, map, extensions)
// are encoded in 0, 1, 2, 4 or 8 bytes.
// Zero-length containers have no length encoded.
// For others, the number of bytes is given by pow(2, bd%3)
// - maps are encoded as [bd] [length] [[key][value]]...
// - arrays are encoded as [bd] [length] [value]...
// - extensions are encoded as [bd] [length] [tag] [byte]...
// - strings/bytearrays are encoded as [bd] [length] [byte]...
//
// The full spec will be published soon.
type SimpleHandle struct {
BasicHandle
}
func (h *SimpleHandle) newEncDriver(w encWriter) encDriver {
return &simpleEncDriver{w: w, h: h}
}
func (h *SimpleHandle) newDecDriver(r decReader) decDriver {
return &simpleDecDriver{r: r, h: h}
}
func (_ *SimpleHandle) writeExt() bool {
return true
}
func (h *SimpleHandle) getBasicHandle() *BasicHandle {
return &h.BasicHandle
}
var _ decDriver = (*simpleDecDriver)(nil)
var _ encDriver = (*simpleEncDriver)(nil)