finclip-app-manager/vendor/github.com/ugorji/go/codec/reader.go

1018 lines
19 KiB
Go

// Copyright (c) 2012-2018 Ugorji Nwoke. All rights reserved.
// Use of this source code is governed by a MIT license found in the LICENSE file.
package codec
import "io"
// decReader abstracts the reading source, allowing implementations that can
// read from an io.Reader or directly off a byte slice with zero-copying.
type decReader interface {
unreadn1()
// readx will use the implementation scratch buffer if possible i.e. n < len(scratchbuf), OR
// just return a view of the []byte being decoded from.
// Ensure you call detachZeroCopyBytes later if this needs to be sent outside codec control.
readx(n uint) []byte
readb([]byte)
readn1() uint8
// read up to 7 bytes at a time
readn(num uint8) (v [rwNLen]byte)
numread() uint // number of bytes read
track()
stopTrack() []byte
// skip will skip any byte that matches, and return the first non-matching byte
skip(accept *bitset256) (token byte)
// readTo will read any byte that matches, stopping once no-longer matching.
readTo(accept *bitset256) (out []byte)
// readUntil will read, only stopping once it matches the 'stop' byte.
readUntil(stop byte, includeLast bool) (out []byte)
}
// ------------------------------------------------
type unreadByteStatus uint8
// unreadByteStatus goes from
// undefined (when initialized) -- (read) --> canUnread -- (unread) --> canRead ...
const (
unreadByteUndefined unreadByteStatus = iota
unreadByteCanRead
unreadByteCanUnread
)
// --------------------
type ioDecReaderCommon struct {
r io.Reader // the reader passed in
n uint // num read
l byte // last byte
ls unreadByteStatus // last byte status
trb bool // tracking bytes turned on
_ bool
b [4]byte // tiny buffer for reading single bytes
blist *bytesFreelist
tr []byte // buffer for tracking bytes
bufr []byte // buffer for readTo/readUntil
}
func (z *ioDecReaderCommon) last() byte {
return z.l
}
func (z *ioDecReaderCommon) reset(r io.Reader, blist *bytesFreelist) {
z.blist = blist
z.r = r
z.ls = unreadByteUndefined
z.l, z.n = 0, 0
z.trb = false
}
func (z *ioDecReaderCommon) numread() uint {
return z.n
}
func (z *ioDecReaderCommon) track() {
z.tr = z.blist.check(z.tr, 256)[:0]
z.trb = true
}
func (z *ioDecReaderCommon) stopTrack() (bs []byte) {
z.trb = false
return z.tr
}
// ------------------------------------------
// ioDecReader is a decReader that reads off an io.Reader.
//
// It also has a fallback implementation of ByteScanner if needed.
type ioDecReader struct {
ioDecReaderCommon
// rr io.Reader
br io.ByteScanner
x [64 + 16]byte // for: get struct field name, swallow valueTypeBytes, etc
// _ [1]uint64 // padding
}
func (z *ioDecReader) reset(r io.Reader, blist *bytesFreelist) {
z.ioDecReaderCommon.reset(r, blist)
z.br, _ = r.(io.ByteScanner)
}
func (z *ioDecReader) Read(p []byte) (n int, err error) {
if len(p) == 0 {
return
}
var firstByte bool
if z.ls == unreadByteCanRead {
z.ls = unreadByteCanUnread
p[0] = z.l
if len(p) == 1 {
n = 1
return
}
firstByte = true
p = p[1:]
}
n, err = z.r.Read(p)
if n > 0 {
if err == io.EOF && n == len(p) {
err = nil // read was successful, so postpone EOF (till next time)
}
z.l = p[n-1]
z.ls = unreadByteCanUnread
}
if firstByte {
n++
}
return
}
func (z *ioDecReader) ReadByte() (c byte, err error) {
if z.br != nil {
c, err = z.br.ReadByte()
if err == nil {
z.l = c
z.ls = unreadByteCanUnread
}
return
}
n, err := z.Read(z.b[:1])
if n == 1 {
c = z.b[0]
if err == io.EOF {
err = nil // read was successful, so postpone EOF (till next time)
}
}
return
}
func (z *ioDecReader) UnreadByte() (err error) {
if z.br != nil {
err = z.br.UnreadByte()
if err == nil {
z.ls = unreadByteCanRead
}
return
}
switch z.ls {
case unreadByteCanUnread:
z.ls = unreadByteCanRead
case unreadByteCanRead:
err = errDecUnreadByteLastByteNotRead
case unreadByteUndefined:
err = errDecUnreadByteNothingToRead
default:
err = errDecUnreadByteUnknown
}
return
}
func (z *ioDecReader) readn(num uint8) (bs [rwNLen]byte) {
z.readb(bs[:num])
// copy(bs[:], z.readx(uint(num)))
return
}
func (z *ioDecReader) readx(n uint) (bs []byte) {
if n == 0 {
return
}
if n < uint(len(z.x)) {
bs = z.x[:n]
} else {
bs = make([]byte, n)
}
if _, err := decReadFull(z.r, bs); err != nil {
panic(err)
}
z.n += uint(len(bs))
if z.trb {
z.tr = append(z.tr, bs...)
}
return
}
func (z *ioDecReader) readb(bs []byte) {
if len(bs) == 0 {
return
}
if _, err := decReadFull(z.r, bs); err != nil {
panic(err)
}
z.n += uint(len(bs))
if z.trb {
z.tr = append(z.tr, bs...)
}
}
func (z *ioDecReader) readn1eof() (b uint8, eof bool) {
b, err := z.ReadByte()
if err == nil {
z.n++
if z.trb {
z.tr = append(z.tr, b)
}
} else if err == io.EOF {
eof = true
} else {
panic(err)
}
return
}
func (z *ioDecReader) readn1() (b uint8) {
b, err := z.ReadByte()
if err == nil {
z.n++
if z.trb {
z.tr = append(z.tr, b)
}
return
}
panic(err)
}
func (z *ioDecReader) skip(accept *bitset256) (token byte) {
var eof bool
LOOP:
token, eof = z.readn1eof()
if eof {
return
}
if accept.isset(token) {
goto LOOP
}
return
}
func (z *ioDecReader) readTo(accept *bitset256) []byte {
z.bufr = z.blist.check(z.bufr, 256)[:0]
LOOP:
token, eof := z.readn1eof()
if eof {
return z.bufr
}
if accept.isset(token) {
z.bufr = append(z.bufr, token)
goto LOOP
}
z.unreadn1()
return z.bufr
}
func (z *ioDecReader) readUntil(stop byte, includeLast bool) []byte {
z.bufr = z.blist.check(z.bufr, 256)[:0]
LOOP:
token, eof := z.readn1eof()
if eof {
panic(io.EOF)
}
z.bufr = append(z.bufr, token)
if token == stop {
if includeLast {
return z.bufr
}
return z.bufr[:len(z.bufr)-1]
}
goto LOOP
}
//go:noinline
func (z *ioDecReader) unreadn1() {
err := z.UnreadByte()
if err != nil {
panic(err)
}
z.n--
if z.trb {
if l := len(z.tr) - 1; l >= 0 {
z.tr = z.tr[:l]
}
}
}
// ------------------------------------
type bufioDecReader struct {
ioDecReaderCommon
c uint // cursor
buf []byte
}
func (z *bufioDecReader) reset(r io.Reader, bufsize int, blist *bytesFreelist) {
z.ioDecReaderCommon.reset(r, blist)
z.c = 0
if cap(z.buf) < bufsize {
z.buf = blist.get(bufsize)
}
z.buf = z.buf[:0]
}
func (z *bufioDecReader) readb(p []byte) {
var n = uint(copy(p, z.buf[z.c:]))
z.n += n
z.c += n
if len(p) == int(n) {
if z.trb {
z.tr = append(z.tr, p...)
}
} else {
z.readbFill(p, n)
}
}
func (z *bufioDecReader) readbFill(p0 []byte, n uint) {
// at this point, there's nothing in z.buf to read (z.buf is fully consumed)
p := p0[n:]
var n2 uint
var err error
if len(p) > cap(z.buf) {
n2, err = decReadFull(z.r, p)
if err != nil {
panic(err)
}
n += n2
z.n += n2
// always keep last byte in z.buf
z.buf = z.buf[:1]
z.buf[0] = p[len(p)-1]
z.c = 1
if z.trb {
z.tr = append(z.tr, p0[:n]...)
}
return
}
// z.c is now 0, and len(p) <= cap(z.buf)
LOOP:
// for len(p) > 0 && z.err == nil {
if len(p) > 0 {
z.buf = z.buf[0:cap(z.buf)]
var n1 int
n1, err = z.r.Read(z.buf)
n2 = uint(n1)
if n2 == 0 && err != nil {
panic(err)
}
z.buf = z.buf[:n2]
n2 = uint(copy(p, z.buf))
z.c = n2
n += n2
z.n += n2
p = p[n2:]
goto LOOP
}
if z.c == 0 {
z.buf = z.buf[:1]
z.buf[0] = p[len(p)-1]
z.c = 1
}
if z.trb {
z.tr = append(z.tr, p0[:n]...)
}
}
func (z *bufioDecReader) last() byte {
return z.buf[z.c-1]
}
func (z *bufioDecReader) readn1() (b byte) {
// fast-path, so we elide calling into Read() most of the time
if z.c < uint(len(z.buf)) {
b = z.buf[z.c]
z.c++
z.n++
if z.trb {
z.tr = append(z.tr, b)
}
} else { // meaning z.c == len(z.buf) or greater ... so need to fill
z.readbFill(z.b[:1], 0)
b = z.b[0]
}
return
}
func (z *bufioDecReader) unreadn1() {
if z.c == 0 {
panic(errDecUnreadByteNothingToRead)
}
z.c--
z.n--
if z.trb {
z.tr = z.tr[:len(z.tr)-1]
}
}
func (z *bufioDecReader) readn(num uint8) (bs [rwNLen]byte) {
z.readb(bs[:num])
// copy(bs[:], z.readx(uint(num)))
return
}
func (z *bufioDecReader) readx(n uint) (bs []byte) {
if n == 0 {
// return
} else if z.c+n <= uint(len(z.buf)) {
bs = z.buf[z.c : z.c+n]
z.n += n
z.c += n
if z.trb {
z.tr = append(z.tr, bs...)
}
} else {
bs = make([]byte, n)
// n no longer used - can reuse
n = uint(copy(bs, z.buf[z.c:]))
z.n += n
z.c += n
z.readbFill(bs, n)
}
return
}
func (z *bufioDecReader) skip(accept *bitset256) (token byte) {
i := z.c
LOOP:
if i < uint(len(z.buf)) {
// inline z.skipLoopFn(i) and refactor, so cost is within inline budget
token = z.buf[i]
i++
if accept.isset(token) {
goto LOOP
}
z.n += i - 2 - z.c
if z.trb {
z.tr = append(z.tr, z.buf[z.c:i]...) // z.doTrack(i)
}
z.c = i
return
}
return z.skipFill(accept)
}
func (z *bufioDecReader) skipFill(accept *bitset256) (token byte) {
z.n += uint(len(z.buf)) - z.c
if z.trb {
z.tr = append(z.tr, z.buf[z.c:]...)
}
var i, n2 int
var err error
for {
z.c = 0
z.buf = z.buf[0:cap(z.buf)]
n2, err = z.r.Read(z.buf)
if n2 == 0 && err != nil {
panic(err)
}
z.buf = z.buf[:n2]
for i, token = range z.buf {
// if !accept.isset(token) {
if accept.check(token) == 0 {
z.n += (uint(i) - z.c) - 1
z.loopFn(uint(i + 1))
return
}
}
z.n += uint(n2)
if z.trb {
z.tr = append(z.tr, z.buf...)
}
}
}
func (z *bufioDecReader) loopFn(i uint) {
if z.trb {
z.tr = append(z.tr, z.buf[z.c:i]...) // z.doTrack(i)
}
z.c = i
}
func (z *bufioDecReader) readTo(accept *bitset256) (out []byte) {
i := z.c
LOOP:
if i < uint(len(z.buf)) {
// if !accept.isset(z.buf[i]) {
if accept.check(z.buf[i]) == 0 {
// inline readToLoopFn here (for performance)
z.n += (i - z.c) - 1
out = z.buf[z.c:i]
if z.trb {
z.tr = append(z.tr, z.buf[z.c:i]...) // z.doTrack(i)
}
z.c = i
return
}
i++
goto LOOP
}
return z.readToFill(accept)
}
func (z *bufioDecReader) readToFill(accept *bitset256) []byte {
z.bufr = z.blist.check(z.bufr, 256)[:0]
z.n += uint(len(z.buf)) - z.c
z.bufr = append(z.bufr, z.buf[z.c:]...)
if z.trb {
z.tr = append(z.tr, z.buf[z.c:]...)
}
var n2 int
var err error
for {
z.c = 0
z.buf = z.buf[:cap(z.buf)]
n2, err = z.r.Read(z.buf)
if n2 == 0 && err != nil {
if err == io.EOF {
return z.bufr // readTo should read until it matches or end is reached
}
panic(err)
}
z.buf = z.buf[:n2]
for i, token := range z.buf {
// if !accept.isset(token) {
if accept.check(token) == 0 {
z.n += (uint(i) - z.c) - 1
z.bufr = append(z.bufr, z.buf[z.c:i]...)
z.loopFn(uint(i))
return z.bufr
}
}
z.bufr = append(z.bufr, z.buf...)
z.n += uint(n2)
if z.trb {
z.tr = append(z.tr, z.buf...)
}
}
}
func (z *bufioDecReader) readUntil(stop byte, includeLast bool) (out []byte) {
i := z.c
LOOP:
if i < uint(len(z.buf)) {
if z.buf[i] == stop {
z.n += (i - z.c) - 1
i++
out = z.buf[z.c:i]
if z.trb {
z.tr = append(z.tr, z.buf[z.c:i]...) // z.doTrack(i)
}
z.c = i
goto FINISH
}
i++
goto LOOP
}
out = z.readUntilFill(stop)
FINISH:
if includeLast {
return
}
return out[:len(out)-1]
}
func (z *bufioDecReader) readUntilFill(stop byte) []byte {
z.bufr = z.blist.check(z.bufr, 256)[:0]
z.n += uint(len(z.buf)) - z.c
z.bufr = append(z.bufr, z.buf[z.c:]...)
if z.trb {
z.tr = append(z.tr, z.buf[z.c:]...)
}
for {
z.c = 0
z.buf = z.buf[0:cap(z.buf)]
n1, err := z.r.Read(z.buf)
if n1 == 0 && err != nil {
panic(err)
}
n2 := uint(n1)
z.buf = z.buf[:n2]
for i, token := range z.buf {
if token == stop {
z.n += (uint(i) - z.c) - 1
z.bufr = append(z.bufr, z.buf[z.c:i+1]...)
z.loopFn(uint(i + 1))
return z.bufr
}
}
z.bufr = append(z.bufr, z.buf...)
z.n += n2
if z.trb {
z.tr = append(z.tr, z.buf...)
}
}
}
// ------------------------------------
// bytesDecReader is a decReader that reads off a byte slice with zero copying
type bytesDecReader struct {
b []byte // data
c uint // cursor
t uint // track start
// a int // available
}
func (z *bytesDecReader) reset(in []byte) {
z.b = in
z.c = 0
z.t = 0
}
func (z *bytesDecReader) numread() uint {
return z.c
}
func (z *bytesDecReader) last() byte {
return z.b[z.c-1]
}
func (z *bytesDecReader) unreadn1() {
if z.c == 0 || len(z.b) == 0 {
panic(errBytesDecReaderCannotUnread)
}
z.c--
}
func (z *bytesDecReader) readx(n uint) (bs []byte) {
// slicing from a non-constant start position is more expensive,
// as more computation is required to decipher the pointer start position.
// However, we do it only once, and it's better than reslicing both z.b and return value.
z.c += n
return z.b[z.c-n : z.c]
}
func (z *bytesDecReader) readb(bs []byte) {
copy(bs, z.readx(uint(len(bs))))
}
func (z *bytesDecReader) readn1() (v uint8) {
v = z.b[z.c]
z.c++
return
}
func (z *bytesDecReader) readn(num uint8) (bs [rwNLen]byte) {
// if z.c >= uint(len(z.b)) || z.c+uint(num) >= uint(len(z.b)) {
// panic(io.EOF)
// }
// for bounds-check elimination, reslice z.b and ensure bs is within len
// bb := z.b[z.c:][:num]
bb := z.b[z.c : z.c+uint(num)]
_ = bs[len(bb)-1]
var i int
LOOP:
if i < len(bb) {
bs[i] = bb[i]
i++
goto LOOP
}
z.c += uint(num)
return
}
func (z *bytesDecReader) skip(accept *bitset256) (token byte) {
i := z.c
LOOP:
// if i < uint(len(z.b)) {
token = z.b[i]
i++
if accept.isset(token) {
goto LOOP
}
z.c = i
return
}
func (z *bytesDecReader) readTo(accept *bitset256) (out []byte) {
i := z.c
LOOP:
if i < uint(len(z.b)) {
if accept.isset(z.b[i]) {
i++
goto LOOP
}
}
out = z.b[z.c:i]
z.c = i
return // z.b[c:i]
}
func (z *bytesDecReader) readUntil(stop byte, includeLast bool) (out []byte) {
i := z.c
LOOP:
// if i < uint(len(z.b)) {
if z.b[i] == stop {
i++
if includeLast {
out = z.b[z.c:i]
} else {
out = z.b[z.c : i-1]
}
// z.a -= (i - z.c)
z.c = i
return
}
i++
goto LOOP
// }
// panic(io.EOF)
}
func (z *bytesDecReader) track() {
z.t = z.c
}
func (z *bytesDecReader) stopTrack() (bs []byte) {
return z.b[z.t:z.c]
}
// --------------
type decRd struct {
mtr bool // is maptype a known type?
str bool // is slicetype a known type?
be bool // is binary encoding
js bool // is json handle
jsms bool // is json handle, and MapKeyAsString
cbor bool // is cbor handle
bytes bool // is bytes reader
bufio bool // is this a bufioDecReader?
rb bytesDecReader
ri *ioDecReader
bi *bufioDecReader
}
// numread, track and stopTrack are always inlined, as they just check int fields, etc.
// the if/else-if/else block is expensive to inline.
// Each node of this construct costs a lot and dominates the budget.
// Best to only do an if fast-path else block (so fast-path is inlined).
// This is irrespective of inlineExtraCallCost set in $GOROOT/src/cmd/compile/internal/gc/inl.go
//
// In decRd methods below, we delegate all IO functions into their own methods.
// This allows for the inlining of the common path when z.bytes=true.
// Go 1.12+ supports inlining methods with up to 1 inlined function (or 2 if no other constructs).
//
// However, up through Go 1.13, decRd's readXXX, skip and unreadXXX methods are not inlined.
// Consequently, there is no benefit to do the xxxIO methods for decRd at this time.
// Instead, we have a if/else-if/else block so that IO calls do not have to jump through
// a second unnecessary function call.
//
// If golang inlining gets better and bytesDecReader methods can be inlined,
// then we can revert to using these 2 functions so the bytesDecReader
// methods are inlined and the IO paths call out to a function.
func (z *decRd) numread() uint {
if z.bytes {
return z.rb.numread()
} else if z.bufio {
return z.bi.numread()
} else {
return z.ri.numread()
}
}
func (z *decRd) stopTrack() []byte {
if z.bytes {
return z.rb.stopTrack()
} else if z.bufio {
return z.bi.stopTrack()
} else {
return z.ri.stopTrack()
}
}
func (z *decRd) track() {
if z.bytes {
z.rb.track()
} else if z.bufio {
z.bi.track()
} else {
z.ri.track()
}
}
func (z *decRd) unreadn1() {
if z.bytes {
z.rb.unreadn1()
} else if z.bufio {
z.bi.unreadn1()
} else {
z.ri.unreadn1() // not inlined
}
}
func (z *decRd) readn(num uint8) [rwNLen]byte {
if z.bytes {
return z.rb.readn(num)
} else if z.bufio {
return z.bi.readn(num)
} else {
return z.ri.readn(num)
}
}
func (z *decRd) readx(n uint) []byte {
if z.bytes {
return z.rb.readx(n)
} else if z.bufio {
return z.bi.readx(n)
} else {
return z.ri.readx(n)
}
}
func (z *decRd) readb(s []byte) {
if z.bytes {
z.rb.readb(s)
} else if z.bufio {
z.bi.readb(s)
} else {
z.ri.readb(s)
}
}
func (z *decRd) readn1() uint8 {
if z.bytes {
return z.rb.readn1()
} else if z.bufio {
return z.bi.readn1()
} else {
return z.ri.readn1()
}
}
func (z *decRd) skip(accept *bitset256) (token byte) {
if z.bytes {
return z.rb.skip(accept)
} else if z.bufio {
return z.bi.skip(accept)
} else {
return z.ri.skip(accept)
}
}
func (z *decRd) readTo(accept *bitset256) (out []byte) {
if z.bytes {
return z.rb.readTo(accept)
} else if z.bufio {
return z.bi.readTo(accept)
} else {
return z.ri.readTo(accept)
}
}
func (z *decRd) readUntil(stop byte, includeLast bool) (out []byte) {
if z.bytes {
return z.rb.readUntil(stop, includeLast)
} else if z.bufio {
return z.bi.readUntil(stop, includeLast)
} else {
return z.ri.readUntil(stop, includeLast)
}
}
/*
func (z *decRd) track() {
if z.bytes {
z.rb.track()
} else {
z.trackIO()
}
}
func (z *decRd) trackIO() {
if z.bufio {
z.bi.track()
} else {
z.ri.track()
}
}
func (z *decRd) unreadn1() {
if z.bytes {
z.rb.unreadn1()
} else {
z.unreadn1IO()
}
}
func (z *decRd) unreadn1IO() {
if z.bufio {
z.bi.unreadn1()
} else {
z.ri.unreadn1()
}
}
func (z *decRd) readn(num uint8) [rwNLen]byte {
if z.bytes {
return z.rb.readn(num)
}
return z.readnIO(num)
}
func (z *decRd) readnIO(num uint8) [rwNLen]byte {
if z.bufio {
return z.bi.readn(num)
}
return z.ri.readn(num)
}
func (z *decRd) readx(n uint) []byte {
if z.bytes {
return z.rb.readx(n)
}
return z.readxIO(n)
}
func (z *decRd) readxIO(n uint) []byte {
if z.bufio {
return z.bi.readx(n)
}
return z.ri.readx(n)
}
func (z *decRd) readb(s []byte) {
if z.bytes {
z.rb.readb(s)
} else {
z.readbIO(s)
}
}
func (z *decRd) readbIO(s []byte) {
if z.bufio {
z.bi.readb(s)
} else {
z.ri.readb(s)
}
}
func (z *decRd) readn1() uint8 {
if z.bytes {
return z.rb.readn1()
}
return z.readn1IO()
}
func (z *decRd) readn1IO() uint8 {
if z.bufio {
return z.bi.readn1()
}
return z.ri.readn1()
}
func (z *decRd) skip(accept *bitset256) (token byte) {
if z.bytes {
return z.rb.skip(accept)
}
return z.skipIO(accept)
}
func (z *decRd) skipIO(accept *bitset256) (token byte) {
if z.bufio {
return z.bi.skip(accept)
}
return z.ri.skip(accept)
}
func (z *decRd) readTo(accept *bitset256) (out []byte) {
if z.bytes {
return z.rb.readTo(accept)
}
return z.readToIO(accept)
}
func (z *decRd) readToIO(accept *bitset256) (out []byte) {
if z.bufio {
return z.bi.readTo(accept)
}
return z.ri.readTo(accept)
}
func (z *decRd) readUntil(stop byte, includeLast bool) (out []byte) {
if z.bytes {
return z.rb.readUntil(stop, includeLast)
}
return z.readUntilIO(stop, includeLast)
}
func (z *decRd) readUntilIO(stop byte, includeLast bool) (out []byte) {
if z.bufio {
return z.bi.readUntil(stop, includeLast)
}
return z.ri.readUntil(stop, includeLast)
}
*/
var _ decReader = (*decRd)(nil)