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author | Alex Pilon <apilon@hashicorp.com> | 2019-02-22 18:24:37 -0500 |
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committer | Alex Pilon <apilon@hashicorp.com> | 2019-02-22 18:24:37 -0500 |
commit | 15c0b25d011f37e7c20aeca9eaf461f78285b8d9 (patch) | |
tree | 255c250a5c9d4801c74092d33b7337d8c14438ff /vendor/github.com/ulikunitz/xz/lzma/treecodecs.go | |
parent | 07971ca38143c5faf951d152fba370ddcbe26ad5 (diff) | |
download | terraform-provider-statuscake-15c0b25d011f37e7c20aeca9eaf461f78285b8d9.tar.gz terraform-provider-statuscake-15c0b25d011f37e7c20aeca9eaf461f78285b8d9.tar.zst terraform-provider-statuscake-15c0b25d011f37e7c20aeca9eaf461f78285b8d9.zip |
deps: github.com/hashicorp/terraform@sdk-v0.11-with-go-modules
Updated via: go get github.com/hashicorp/terraform@sdk-v0.11-with-go-modules and go mod tidy
Diffstat (limited to 'vendor/github.com/ulikunitz/xz/lzma/treecodecs.go')
-rw-r--r-- | vendor/github.com/ulikunitz/xz/lzma/treecodecs.go | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/vendor/github.com/ulikunitz/xz/lzma/treecodecs.go b/vendor/github.com/ulikunitz/xz/lzma/treecodecs.go new file mode 100644 index 0000000..504b3d7 --- /dev/null +++ b/vendor/github.com/ulikunitz/xz/lzma/treecodecs.go | |||
@@ -0,0 +1,133 @@ | |||
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 | // treeCodec encodes or decodes values with a fixed bit size. It is using a | ||
8 | // tree of probability value. The root of the tree is the most-significant bit. | ||
9 | type treeCodec struct { | ||
10 | probTree | ||
11 | } | ||
12 | |||
13 | // makeTreeCodec makes a tree codec. The bits value must be inside the range | ||
14 | // [1,32]. | ||
15 | func makeTreeCodec(bits int) treeCodec { | ||
16 | return treeCodec{makeProbTree(bits)} | ||
17 | } | ||
18 | |||
19 | // deepcopy initializes tc as a deep copy of the source. | ||
20 | func (tc *treeCodec) deepcopy(src *treeCodec) { | ||
21 | tc.probTree.deepcopy(&src.probTree) | ||
22 | } | ||
23 | |||
24 | // Encode uses the range encoder to encode a fixed-bit-size value. | ||
25 | func (tc *treeCodec) Encode(e *rangeEncoder, v uint32) (err error) { | ||
26 | m := uint32(1) | ||
27 | for i := int(tc.bits) - 1; i >= 0; i-- { | ||
28 | b := (v >> uint(i)) & 1 | ||
29 | if err := e.EncodeBit(b, &tc.probs[m]); err != nil { | ||
30 | return err | ||
31 | } | ||
32 | m = (m << 1) | b | ||
33 | } | ||
34 | return nil | ||
35 | } | ||
36 | |||
37 | // Decodes uses the range decoder to decode a fixed-bit-size value. Errors may | ||
38 | // be caused by the range decoder. | ||
39 | func (tc *treeCodec) Decode(d *rangeDecoder) (v uint32, err error) { | ||
40 | m := uint32(1) | ||
41 | for j := 0; j < int(tc.bits); j++ { | ||
42 | b, err := d.DecodeBit(&tc.probs[m]) | ||
43 | if err != nil { | ||
44 | return 0, err | ||
45 | } | ||
46 | m = (m << 1) | b | ||
47 | } | ||
48 | return m - (1 << uint(tc.bits)), nil | ||
49 | } | ||
50 | |||
51 | // treeReverseCodec is another tree codec, where the least-significant bit is | ||
52 | // the start of the probability tree. | ||
53 | type treeReverseCodec struct { | ||
54 | probTree | ||
55 | } | ||
56 | |||
57 | // deepcopy initializes the treeReverseCodec as a deep copy of the | ||
58 | // source. | ||
59 | func (tc *treeReverseCodec) deepcopy(src *treeReverseCodec) { | ||
60 | tc.probTree.deepcopy(&src.probTree) | ||
61 | } | ||
62 | |||
63 | // makeTreeReverseCodec creates treeReverseCodec value. The bits argument must | ||
64 | // be in the range [1,32]. | ||
65 | func makeTreeReverseCodec(bits int) treeReverseCodec { | ||
66 | return treeReverseCodec{makeProbTree(bits)} | ||
67 | } | ||
68 | |||
69 | // Encode uses range encoder to encode a fixed-bit-size value. The range | ||
70 | // encoder may cause errors. | ||
71 | func (tc *treeReverseCodec) Encode(v uint32, e *rangeEncoder) (err error) { | ||
72 | m := uint32(1) | ||
73 | for i := uint(0); i < uint(tc.bits); i++ { | ||
74 | b := (v >> i) & 1 | ||
75 | if err := e.EncodeBit(b, &tc.probs[m]); err != nil { | ||
76 | return err | ||
77 | } | ||
78 | m = (m << 1) | b | ||
79 | } | ||
80 | return nil | ||
81 | } | ||
82 | |||
83 | // Decodes uses the range decoder to decode a fixed-bit-size value. Errors | ||
84 | // returned by the range decoder will be returned. | ||
85 | func (tc *treeReverseCodec) Decode(d *rangeDecoder) (v uint32, err error) { | ||
86 | m := uint32(1) | ||
87 | for j := uint(0); j < uint(tc.bits); j++ { | ||
88 | b, err := d.DecodeBit(&tc.probs[m]) | ||
89 | if err != nil { | ||
90 | return 0, err | ||
91 | } | ||
92 | m = (m << 1) | b | ||
93 | v |= b << j | ||
94 | } | ||
95 | return v, nil | ||
96 | } | ||
97 | |||
98 | // probTree stores enough probability values to be used by the treeEncode and | ||
99 | // treeDecode methods of the range coder types. | ||
100 | type probTree struct { | ||
101 | probs []prob | ||
102 | bits byte | ||
103 | } | ||
104 | |||
105 | // deepcopy initializes the probTree value as a deep copy of the source. | ||
106 | func (t *probTree) deepcopy(src *probTree) { | ||
107 | if t == src { | ||
108 | return | ||
109 | } | ||
110 | t.probs = make([]prob, len(src.probs)) | ||
111 | copy(t.probs, src.probs) | ||
112 | t.bits = src.bits | ||
113 | } | ||
114 | |||
115 | // makeProbTree initializes a probTree structure. | ||
116 | func makeProbTree(bits int) probTree { | ||
117 | if !(1 <= bits && bits <= 32) { | ||
118 | panic("bits outside of range [1,32]") | ||
119 | } | ||
120 | t := probTree{ | ||
121 | bits: byte(bits), | ||
122 | probs: make([]prob, 1<<uint(bits)), | ||
123 | } | ||
124 | for i := range t.probs { | ||
125 | t.probs[i] = probInit | ||
126 | } | ||
127 | return t | ||
128 | } | ||
129 | |||
130 | // Bits provides the number of bits for the values to de- or encode. | ||
131 | func (t *probTree) Bits() int { | ||
132 | return int(t.bits) | ||
133 | } | ||