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