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author | Daniel J Walsh <dwalsh@redhat.com> | 2018-07-08 07:55:30 -0400 |
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committer | Atomic Bot <atomic-devel@projectatomic.io> | 2018-07-19 18:43:32 +0000 |
commit | 98703eb204923f06555605c648fc165a55214520 (patch) | |
tree | a407bae8b3489d4f9b0f0d0f228658bbfe95a38e /vendor/github.com/ulikunitz/xz/lzma/lengthcodec.go | |
parent | c020db8cd21cb221cfbe36b264e0ec02999596ed (diff) | |
download | podman-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.go | 129 |
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 +} |