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authorDaniel J Walsh <dwalsh@redhat.com>2018-07-08 07:55:30 -0400
committerAtomic Bot <atomic-devel@projectatomic.io>2018-07-19 18:43:32 +0000
commit98703eb204923f06555605c648fc165a55214520 (patch)
treea407bae8b3489d4f9b0f0d0f228658bbfe95a38e /vendor/github.com/ulikunitz/xz/lzma/encoder.go
parentc020db8cd21cb221cfbe36b264e0ec02999596ed (diff)
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Vendor in latest code for storage,image, buildah
vendor in containers/storage vendor in containers/image vendor in projectatomic/buildah Signed-off-by: Daniel J Walsh <dwalsh@redhat.com> Closes: #1114 Approved by: mheon
Diffstat (limited to 'vendor/github.com/ulikunitz/xz/lzma/encoder.go')
-rw-r--r--vendor/github.com/ulikunitz/xz/lzma/encoder.go268
1 files changed, 268 insertions, 0 deletions
diff --git a/vendor/github.com/ulikunitz/xz/lzma/encoder.go b/vendor/github.com/ulikunitz/xz/lzma/encoder.go
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+++ b/vendor/github.com/ulikunitz/xz/lzma/encoder.go
@@ -0,0 +1,268 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+ "fmt"
+ "io"
+)
+
+// opLenMargin provides the upper limit of the number of bytes required
+// to encode a single operation.
+const opLenMargin = 10
+
+// compressFlags control the compression process.
+type compressFlags uint32
+
+// Values for compressFlags.
+const (
+ // all data should be compressed, even if compression is not
+ // optimal.
+ all compressFlags = 1 << iota
+)
+
+// encoderFlags provide the flags for an encoder.
+type encoderFlags uint32
+
+// Flags for the encoder.
+const (
+ // eosMarker requests an EOS marker to be written.
+ eosMarker encoderFlags = 1 << iota
+)
+
+// Encoder compresses data buffered in the encoder dictionary and writes
+// it into a byte writer.
+type encoder struct {
+ dict *encoderDict
+ state *state
+ re *rangeEncoder
+ start int64
+ // generate eos marker
+ marker bool
+ limit bool
+ margin int
+}
+
+// newEncoder creates a new encoder. If the byte writer must be
+// limited use LimitedByteWriter provided by this package. The flags
+// argument supports the eosMarker flag, controlling whether a
+// terminating end-of-stream marker must be written.
+func newEncoder(bw io.ByteWriter, state *state, dict *encoderDict,
+ flags encoderFlags) (e *encoder, err error) {
+
+ re, err := newRangeEncoder(bw)
+ if err != nil {
+ return nil, err
+ }
+ e = &encoder{
+ dict: dict,
+ state: state,
+ re: re,
+ marker: flags&eosMarker != 0,
+ start: dict.Pos(),
+ margin: opLenMargin,
+ }
+ if e.marker {
+ e.margin += 5
+ }
+ return e, nil
+}
+
+// Write writes the bytes from p into the dictionary. If not enough
+// space is available the data in the dictionary buffer will be
+// compressed to make additional space available. If the limit of the
+// underlying writer has been reached ErrLimit will be returned.
+func (e *encoder) Write(p []byte) (n int, err error) {
+ for {
+ k, err := e.dict.Write(p[n:])
+ n += k
+ if err == ErrNoSpace {
+ if err = e.compress(0); err != nil {
+ return n, err
+ }
+ continue
+ }
+ return n, err
+ }
+}
+
+// Reopen reopens the encoder with a new byte writer.
+func (e *encoder) Reopen(bw io.ByteWriter) error {
+ var err error
+ if e.re, err = newRangeEncoder(bw); err != nil {
+ return err
+ }
+ e.start = e.dict.Pos()
+ e.limit = false
+ return nil
+}
+
+// writeLiteral writes a literal into the LZMA stream
+func (e *encoder) writeLiteral(l lit) error {
+ var err error
+ state, state2, _ := e.state.states(e.dict.Pos())
+ if err = e.state.isMatch[state2].Encode(e.re, 0); err != nil {
+ return err
+ }
+ litState := e.state.litState(e.dict.ByteAt(1), e.dict.Pos())
+ match := e.dict.ByteAt(int(e.state.rep[0]) + 1)
+ err = e.state.litCodec.Encode(e.re, l.b, state, match, litState)
+ if err != nil {
+ return err
+ }
+ e.state.updateStateLiteral()
+ return nil
+}
+
+// iverson implements the Iverson operator as proposed by Donald Knuth in his
+// book Concrete Mathematics.
+func iverson(ok bool) uint32 {
+ if ok {
+ return 1
+ }
+ return 0
+}
+
+// writeMatch writes a repetition operation into the operation stream
+func (e *encoder) writeMatch(m match) error {
+ var err error
+ if !(minDistance <= m.distance && m.distance <= maxDistance) {
+ panic(fmt.Errorf("match distance %d out of range", m.distance))
+ }
+ dist := uint32(m.distance - minDistance)
+ if !(minMatchLen <= m.n && m.n <= maxMatchLen) &&
+ !(dist == e.state.rep[0] && m.n == 1) {
+ panic(fmt.Errorf(
+ "match length %d out of range; dist %d rep[0] %d",
+ m.n, dist, e.state.rep[0]))
+ }
+ state, state2, posState := e.state.states(e.dict.Pos())
+ if err = e.state.isMatch[state2].Encode(e.re, 1); err != nil {
+ return err
+ }
+ g := 0
+ for ; g < 4; g++ {
+ if e.state.rep[g] == dist {
+ break
+ }
+ }
+ b := iverson(g < 4)
+ if err = e.state.isRep[state].Encode(e.re, b); err != nil {
+ return err
+ }
+ n := uint32(m.n - minMatchLen)
+ if b == 0 {
+ // simple match
+ e.state.rep[3], e.state.rep[2], e.state.rep[1], e.state.rep[0] =
+ e.state.rep[2], e.state.rep[1], e.state.rep[0], dist
+ e.state.updateStateMatch()
+ if err = e.state.lenCodec.Encode(e.re, n, posState); err != nil {
+ return err
+ }
+ return e.state.distCodec.Encode(e.re, dist, n)
+ }
+ b = iverson(g != 0)
+ if err = e.state.isRepG0[state].Encode(e.re, b); err != nil {
+ return err
+ }
+ if b == 0 {
+ // g == 0
+ b = iverson(m.n != 1)
+ if err = e.state.isRepG0Long[state2].Encode(e.re, b); err != nil {
+ return err
+ }
+ if b == 0 {
+ e.state.updateStateShortRep()
+ return nil
+ }
+ } else {
+ // g in {1,2,3}
+ b = iverson(g != 1)
+ if err = e.state.isRepG1[state].Encode(e.re, b); err != nil {
+ return err
+ }
+ if b == 1 {
+ // g in {2,3}
+ b = iverson(g != 2)
+ err = e.state.isRepG2[state].Encode(e.re, b)
+ if err != nil {
+ return err
+ }
+ if b == 1 {
+ e.state.rep[3] = e.state.rep[2]
+ }
+ e.state.rep[2] = e.state.rep[1]
+ }
+ e.state.rep[1] = e.state.rep[0]
+ e.state.rep[0] = dist
+ }
+ e.state.updateStateRep()
+ return e.state.repLenCodec.Encode(e.re, n, posState)
+}
+
+// writeOp writes a single operation to the range encoder. The function
+// checks whether there is enough space available to close the LZMA
+// stream.
+func (e *encoder) writeOp(op operation) error {
+ if e.re.Available() < int64(e.margin) {
+ return ErrLimit
+ }
+ switch x := op.(type) {
+ case lit:
+ return e.writeLiteral(x)
+ case match:
+ return e.writeMatch(x)
+ default:
+ panic("unexpected operation")
+ }
+}
+
+// compress compressed data from the dictionary buffer. If the flag all
+// is set, all data in the dictionary buffer will be compressed. The
+// function returns ErrLimit if the underlying writer has reached its
+// limit.
+func (e *encoder) compress(flags compressFlags) error {
+ n := 0
+ if flags&all == 0 {
+ n = maxMatchLen - 1
+ }
+ d := e.dict
+ m := d.m
+ for d.Buffered() > n {
+ op := m.NextOp(e.state.rep)
+ if err := e.writeOp(op); err != nil {
+ return err
+ }
+ d.Discard(op.Len())
+ }
+ return nil
+}
+
+// eosMatch is a pseudo operation that indicates the end of the stream.
+var eosMatch = match{distance: maxDistance, n: minMatchLen}
+
+// Close terminates the LZMA stream. If requested the end-of-stream
+// marker will be written. If the byte writer limit has been or will be
+// reached during compression of the remaining data in the buffer the
+// LZMA stream will be closed and data will remain in the buffer.
+func (e *encoder) Close() error {
+ err := e.compress(all)
+ if err != nil && err != ErrLimit {
+ return err
+ }
+ if e.marker {
+ if err := e.writeMatch(eosMatch); err != nil {
+ return err
+ }
+ }
+ err = e.re.Close()
+ return err
+}
+
+// Compressed returns the number bytes of the input data that been
+// compressed.
+func (e *encoder) Compressed() int64 {
+ return e.dict.Pos() - e.start
+}