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author | appilon <apilon@hashicorp.com> | 2019-02-27 16:43:31 -0500 |
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committer | GitHub <noreply@github.com> | 2019-02-27 16:43:31 -0500 |
commit | 844b5a68d8af4791755b8f0ad293cc99f5959183 (patch) | |
tree | 255c250a5c9d4801c74092d33b7337d8c14438ff /vendor/github.com/ulikunitz/xz/lzma/lengthcodec.go | |
parent | 303b299eeb6b06e939e35905e4b34cb410dd9dc3 (diff) | |
parent | 15c0b25d011f37e7c20aeca9eaf461f78285b8d9 (diff) | |
download | terraform-provider-statuscake-844b5a68d8af4791755b8f0ad293cc99f5959183.tar.gz terraform-provider-statuscake-844b5a68d8af4791755b8f0ad293cc99f5959183.tar.zst terraform-provider-statuscake-844b5a68d8af4791755b8f0ad293cc99f5959183.zip |
Merge pull request #27 from terraform-providers/go-modules-2019-02-22
[MODULES] Switch to Go Modules
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 0000000..e517730 --- /dev/null +++ b/vendor/github.com/ulikunitz/xz/lzma/lengthcodec.go | |||
@@ -0,0 +1,129 @@ | |||
1 | // Copyright 2014-2017 Ulrich Kunitz. All rights reserved. | ||
2 | // Use of this source code is governed by a BSD-style | ||
3 | // license that can be found in the LICENSE file. | ||
4 | |||
5 | package lzma | ||
6 | |||
7 | import "errors" | ||
8 | |||
9 | // maxPosBits defines the number of bits of the position value that are used to | ||
10 | // to compute the posState value. The value is used to select the tree codec | ||
11 | // for length encoding and decoding. | ||
12 | const maxPosBits = 4 | ||
13 | |||
14 | // minMatchLen and maxMatchLen give the minimum and maximum values for | ||
15 | // encoding and decoding length values. minMatchLen is also used as base | ||
16 | // for the encoded length values. | ||
17 | const ( | ||
18 | minMatchLen = 2 | ||
19 | maxMatchLen = minMatchLen + 16 + 256 - 1 | ||
20 | ) | ||
21 | |||
22 | // lengthCodec support the encoding of the length value. | ||
23 | type lengthCodec struct { | ||
24 | choice [2]prob | ||
25 | low [1 << maxPosBits]treeCodec | ||
26 | mid [1 << maxPosBits]treeCodec | ||
27 | high treeCodec | ||
28 | } | ||
29 | |||
30 | // deepcopy initializes the lc value as deep copy of the source value. | ||
31 | func (lc *lengthCodec) deepcopy(src *lengthCodec) { | ||
32 | if lc == src { | ||
33 | return | ||
34 | } | ||
35 | lc.choice = src.choice | ||
36 | for i := range lc.low { | ||
37 | lc.low[i].deepcopy(&src.low[i]) | ||
38 | } | ||
39 | for i := range lc.mid { | ||
40 | lc.mid[i].deepcopy(&src.mid[i]) | ||
41 | } | ||
42 | lc.high.deepcopy(&src.high) | ||
43 | } | ||
44 | |||
45 | // init initializes a new length codec. | ||
46 | func (lc *lengthCodec) init() { | ||
47 | for i := range lc.choice { | ||
48 | lc.choice[i] = probInit | ||
49 | } | ||
50 | for i := range lc.low { | ||
51 | lc.low[i] = makeTreeCodec(3) | ||
52 | } | ||
53 | for i := range lc.mid { | ||
54 | lc.mid[i] = makeTreeCodec(3) | ||
55 | } | ||
56 | lc.high = makeTreeCodec(8) | ||
57 | } | ||
58 | |||
59 | // lBits gives the number of bits used for the encoding of the l value | ||
60 | // provided to the range encoder. | ||
61 | func lBits(l uint32) int { | ||
62 | switch { | ||
63 | case l < 8: | ||
64 | return 4 | ||
65 | case l < 16: | ||
66 | return 5 | ||
67 | default: | ||
68 | return 10 | ||
69 | } | ||
70 | } | ||
71 | |||
72 | // Encode encodes the length offset. The length offset l can be compute by | ||
73 | // subtracting minMatchLen (2) from the actual length. | ||
74 | // | ||
75 | // l = length - minMatchLen | ||
76 | // | ||
77 | func (lc *lengthCodec) Encode(e *rangeEncoder, l uint32, posState uint32, | ||
78 | ) (err error) { | ||
79 | if l > maxMatchLen-minMatchLen { | ||
80 | return errors.New("lengthCodec.Encode: l out of range") | ||
81 | } | ||
82 | if l < 8 { | ||
83 | if err = lc.choice[0].Encode(e, 0); err != nil { | ||
84 | return | ||
85 | } | ||
86 | return lc.low[posState].Encode(e, l) | ||
87 | } | ||
88 | if err = lc.choice[0].Encode(e, 1); err != nil { | ||
89 | return | ||
90 | } | ||
91 | if l < 16 { | ||
92 | if err = lc.choice[1].Encode(e, 0); err != nil { | ||
93 | return | ||
94 | } | ||
95 | return lc.mid[posState].Encode(e, l-8) | ||
96 | } | ||
97 | if err = lc.choice[1].Encode(e, 1); err != nil { | ||
98 | return | ||
99 | } | ||
100 | if err = lc.high.Encode(e, l-16); err != nil { | ||
101 | return | ||
102 | } | ||
103 | return nil | ||
104 | } | ||
105 | |||
106 | // Decode reads the length offset. Add minMatchLen to compute the actual length | ||
107 | // to the length offset l. | ||
108 | func (lc *lengthCodec) Decode(d *rangeDecoder, posState uint32, | ||
109 | ) (l uint32, err error) { | ||
110 | var b uint32 | ||
111 | if b, err = lc.choice[0].Decode(d); err != nil { | ||
112 | return | ||
113 | } | ||
114 | if b == 0 { | ||
115 | l, err = lc.low[posState].Decode(d) | ||
116 | return | ||
117 | } | ||
118 | if b, err = lc.choice[1].Decode(d); err != nil { | ||
119 | return | ||
120 | } | ||
121 | if b == 0 { | ||
122 | l, err = lc.mid[posState].Decode(d) | ||
123 | l += 8 | ||
124 | return | ||
125 | } | ||
126 | l, err = lc.high.Decode(d) | ||
127 | l += 16 | ||
128 | return | ||
129 | } | ||