summaryrefslogtreecommitdiff
path: root/vendor/github.com/ulikunitz/xz/lzma/lengthcodec.go
diff options
context:
space:
mode:
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/lengthcodec.go
parentc020db8cd21cb221cfbe36b264e0ec02999596ed (diff)
downloadpodman-98703eb204923f06555605c648fc165a55214520.tar.gz
podman-98703eb204923f06555605c648fc165a55214520.tar.bz2
podman-98703eb204923f06555605c648fc165a55214520.zip
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/lengthcodec.go')
-rw-r--r--vendor/github.com/ulikunitz/xz/lzma/lengthcodec.go129
1 files changed, 129 insertions, 0 deletions
diff --git a/vendor/github.com/ulikunitz/xz/lzma/lengthcodec.go b/vendor/github.com/ulikunitz/xz/lzma/lengthcodec.go
new file mode 100644
index 000000000..e51773092
--- /dev/null
+++ b/vendor/github.com/ulikunitz/xz/lzma/lengthcodec.go
@@ -0,0 +1,129 @@
+// 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 "errors"
+
+// maxPosBits defines the number of bits of the position value that are used to
+// to compute the posState value. The value is used to select the tree codec
+// for length encoding and decoding.
+const maxPosBits = 4
+
+// minMatchLen and maxMatchLen give the minimum and maximum values for
+// encoding and decoding length values. minMatchLen is also used as base
+// for the encoded length values.
+const (
+ minMatchLen = 2
+ maxMatchLen = minMatchLen + 16 + 256 - 1
+)
+
+// lengthCodec support the encoding of the length value.
+type lengthCodec struct {
+ choice [2]prob
+ low [1 << maxPosBits]treeCodec
+ mid [1 << maxPosBits]treeCodec
+ high treeCodec
+}
+
+// deepcopy initializes the lc value as deep copy of the source value.
+func (lc *lengthCodec) deepcopy(src *lengthCodec) {
+ if lc == src {
+ return
+ }
+ lc.choice = src.choice
+ for i := range lc.low {
+ lc.low[i].deepcopy(&src.low[i])
+ }
+ for i := range lc.mid {
+ lc.mid[i].deepcopy(&src.mid[i])
+ }
+ lc.high.deepcopy(&src.high)
+}
+
+// init initializes a new length codec.
+func (lc *lengthCodec) init() {
+ for i := range lc.choice {
+ lc.choice[i] = probInit
+ }
+ for i := range lc.low {
+ lc.low[i] = makeTreeCodec(3)
+ }
+ for i := range lc.mid {
+ lc.mid[i] = makeTreeCodec(3)
+ }
+ lc.high = makeTreeCodec(8)
+}
+
+// lBits gives the number of bits used for the encoding of the l value
+// provided to the range encoder.
+func lBits(l uint32) int {
+ switch {
+ case l < 8:
+ return 4
+ case l < 16:
+ return 5
+ default:
+ return 10
+ }
+}
+
+// Encode encodes the length offset. The length offset l can be compute by
+// subtracting minMatchLen (2) from the actual length.
+//
+// l = length - minMatchLen
+//
+func (lc *lengthCodec) Encode(e *rangeEncoder, l uint32, posState uint32,
+) (err error) {
+ if l > maxMatchLen-minMatchLen {
+ return errors.New("lengthCodec.Encode: l out of range")
+ }
+ if l < 8 {
+ if err = lc.choice[0].Encode(e, 0); err != nil {
+ return
+ }
+ return lc.low[posState].Encode(e, l)
+ }
+ if err = lc.choice[0].Encode(e, 1); err != nil {
+ return
+ }
+ if l < 16 {
+ if err = lc.choice[1].Encode(e, 0); err != nil {
+ return
+ }
+ return lc.mid[posState].Encode(e, l-8)
+ }
+ if err = lc.choice[1].Encode(e, 1); err != nil {
+ return
+ }
+ if err = lc.high.Encode(e, l-16); err != nil {
+ return
+ }
+ return nil
+}
+
+// Decode reads the length offset. Add minMatchLen to compute the actual length
+// to the length offset l.
+func (lc *lengthCodec) Decode(d *rangeDecoder, posState uint32,
+) (l uint32, err error) {
+ var b uint32
+ if b, err = lc.choice[0].Decode(d); err != nil {
+ return
+ }
+ if b == 0 {
+ l, err = lc.low[posState].Decode(d)
+ return
+ }
+ if b, err = lc.choice[1].Decode(d); err != nil {
+ return
+ }
+ if b == 0 {
+ l, err = lc.mid[posState].Decode(d)
+ l += 8
+ return
+ }
+ l, err = lc.high.Decode(d)
+ l += 16
+ return
+}