1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
|
package chardet
import (
"bytes"
)
var (
utf16beBom = []byte{0xFE, 0xFF}
utf16leBom = []byte{0xFF, 0xFE}
utf32beBom = []byte{0x00, 0x00, 0xFE, 0xFF}
utf32leBom = []byte{0xFF, 0xFE, 0x00, 0x00}
)
type recognizerUtf16be struct {
}
func newRecognizer_utf16be() *recognizerUtf16be {
return &recognizerUtf16be{}
}
func (*recognizerUtf16be) Match(input *recognizerInput) (output recognizerOutput) {
output = recognizerOutput{
Charset: "UTF-16BE",
}
if bytes.HasPrefix(input.raw, utf16beBom) {
output.Confidence = 100
}
return
}
type recognizerUtf16le struct {
}
func newRecognizer_utf16le() *recognizerUtf16le {
return &recognizerUtf16le{}
}
func (*recognizerUtf16le) Match(input *recognizerInput) (output recognizerOutput) {
output = recognizerOutput{
Charset: "UTF-16LE",
}
if bytes.HasPrefix(input.raw, utf16leBom) && !bytes.HasPrefix(input.raw, utf32leBom) {
output.Confidence = 100
}
return
}
type recognizerUtf32 struct {
name string
bom []byte
decodeChar func(input []byte) uint32
}
func decodeUtf32be(input []byte) uint32 {
return uint32(input[0])<<24 | uint32(input[1])<<16 | uint32(input[2])<<8 | uint32(input[3])
}
func decodeUtf32le(input []byte) uint32 {
return uint32(input[3])<<24 | uint32(input[2])<<16 | uint32(input[1])<<8 | uint32(input[0])
}
func newRecognizer_utf32be() *recognizerUtf32 {
return &recognizerUtf32{
"UTF-32BE",
utf32beBom,
decodeUtf32be,
}
}
func newRecognizer_utf32le() *recognizerUtf32 {
return &recognizerUtf32{
"UTF-32LE",
utf32leBom,
decodeUtf32le,
}
}
func (r *recognizerUtf32) Match(input *recognizerInput) (output recognizerOutput) {
output = recognizerOutput{
Charset: r.name,
}
hasBom := bytes.HasPrefix(input.raw, r.bom)
var numValid, numInvalid uint32
for b := input.raw; len(b) >= 4; b = b[4:] {
if c := r.decodeChar(b); c >= 0x10FFFF || (c >= 0xD800 && c <= 0xDFFF) {
numInvalid++
} else {
numValid++
}
}
if hasBom && numInvalid == 0 {
output.Confidence = 100
} else if hasBom && numValid > numInvalid*10 {
output.Confidence = 80
} else if numValid > 3 && numInvalid == 0 {
output.Confidence = 100
} else if numValid > 0 && numInvalid == 0 {
output.Confidence = 80
} else if numValid > numInvalid*10 {
output.Confidence = 25
}
return
}
|
