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
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
|
// Copyright (C) 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
**********************************************************************
* Copyright (C) 2005-2016, International Business Machines
* Corporation and others. All Rights Reserved.
**********************************************************************
*/
#include "unicode/utypes.h"
#if !UCONFIG_NO_CONVERSION
#include "cmemory.h"
#include "cstring.h"
#include "csr2022.h"
#include "csmatch.h"
U_NAMESPACE_BEGIN
/**
* Matching function shared among the 2022 detectors JP, CN and KR
* Counts up the number of legal and unrecognized escape sequences in
* the sample of text, and computes a score based on the total number &
* the proportion that fit the encoding.
*
*
* @param text the byte buffer containing text to analyse
* @param textLen the size of the text in the byte.
* @param escapeSequences the byte escape sequences to test for.
* @return match quality, in the range of 0-100.
*/
int32_t CharsetRecog_2022::match_2022(const uint8_t *text, int32_t textLen, const uint8_t escapeSequences[][5], int32_t escapeSequences_length) const
{
int32_t i, j;
int32_t escN;
int32_t hits = 0;
int32_t misses = 0;
int32_t shifts = 0;
int32_t quality;
i = 0;
while(i < textLen) {
if(text[i] == 0x1B) {
escN = 0;
while(escN < escapeSequences_length) {
const uint8_t *seq = escapeSequences[escN];
int32_t seq_length = (int32_t)uprv_strlen((const char *) seq);
if (textLen-i >= seq_length) {
j = 1;
while(j < seq_length) {
if(seq[j] != text[i+j]) {
goto checkEscapes;
}
j += 1;
}
hits += 1;
i += seq_length-1;
goto scanInput;
}
// else we ran out of string to compare this time.
checkEscapes:
escN += 1;
}
misses += 1;
}
if( text[i]== 0x0e || text[i] == 0x0f){
shifts += 1;
}
scanInput:
i += 1;
}
if (hits == 0) {
return 0;
}
//
// Initial quality is based on relative proportion of recongized vs.
// unrecognized escape sequences.
// All good: quality = 100;
// half or less good: quality = 0;
// linear inbetween.
quality = (100*hits - 100*misses) / (hits + misses);
// Back off quality if there were too few escape sequences seen.
// Include shifts in this computation, so that KR does not get penalized
// for having only a single Escape sequence, but many shifts.
if (hits+shifts < 5) {
quality -= (5-(hits+shifts))*10;
}
if (quality < 0) {
quality = 0;
}
return quality;
}
static const uint8_t escapeSequences_2022JP[][5] = {
{0x1b, 0x24, 0x28, 0x43, 0x00}, // KS X 1001:1992
{0x1b, 0x24, 0x28, 0x44, 0x00}, // JIS X 212-1990
{0x1b, 0x24, 0x40, 0x00, 0x00}, // JIS C 6226-1978
{0x1b, 0x24, 0x41, 0x00, 0x00}, // GB 2312-80
{0x1b, 0x24, 0x42, 0x00, 0x00}, // JIS X 208-1983
{0x1b, 0x26, 0x40, 0x00, 0x00}, // JIS X 208 1990, 1997
{0x1b, 0x28, 0x42, 0x00, 0x00}, // ASCII
{0x1b, 0x28, 0x48, 0x00, 0x00}, // JIS-Roman
{0x1b, 0x28, 0x49, 0x00, 0x00}, // Half-width katakana
{0x1b, 0x28, 0x4a, 0x00, 0x00}, // JIS-Roman
{0x1b, 0x2e, 0x41, 0x00, 0x00}, // ISO 8859-1
{0x1b, 0x2e, 0x46, 0x00, 0x00} // ISO 8859-7
};
#if !UCONFIG_ONLY_HTML_CONVERSION
static const uint8_t escapeSequences_2022KR[][5] = {
{0x1b, 0x24, 0x29, 0x43, 0x00}
};
static const uint8_t escapeSequences_2022CN[][5] = {
{0x1b, 0x24, 0x29, 0x41, 0x00}, // GB 2312-80
{0x1b, 0x24, 0x29, 0x47, 0x00}, // CNS 11643-1992 Plane 1
{0x1b, 0x24, 0x2A, 0x48, 0x00}, // CNS 11643-1992 Plane 2
{0x1b, 0x24, 0x29, 0x45, 0x00}, // ISO-IR-165
{0x1b, 0x24, 0x2B, 0x49, 0x00}, // CNS 11643-1992 Plane 3
{0x1b, 0x24, 0x2B, 0x4A, 0x00}, // CNS 11643-1992 Plane 4
{0x1b, 0x24, 0x2B, 0x4B, 0x00}, // CNS 11643-1992 Plane 5
{0x1b, 0x24, 0x2B, 0x4C, 0x00}, // CNS 11643-1992 Plane 6
{0x1b, 0x24, 0x2B, 0x4D, 0x00}, // CNS 11643-1992 Plane 7
{0x1b, 0x4e, 0x00, 0x00, 0x00}, // SS2
{0x1b, 0x4f, 0x00, 0x00, 0x00}, // SS3
};
#endif
CharsetRecog_2022JP::~CharsetRecog_2022JP() {}
const char *CharsetRecog_2022JP::getName() const {
return "ISO-2022-JP";
}
UBool CharsetRecog_2022JP::match(InputText *textIn, CharsetMatch *results) const {
int32_t confidence = match_2022(textIn->fInputBytes,
textIn->fInputLen,
escapeSequences_2022JP,
UPRV_LENGTHOF(escapeSequences_2022JP));
results->set(textIn, this, confidence);
return (confidence > 0);
}
#if !UCONFIG_ONLY_HTML_CONVERSION
CharsetRecog_2022KR::~CharsetRecog_2022KR() {}
const char *CharsetRecog_2022KR::getName() const {
return "ISO-2022-KR";
}
UBool CharsetRecog_2022KR::match(InputText *textIn, CharsetMatch *results) const {
int32_t confidence = match_2022(textIn->fInputBytes,
textIn->fInputLen,
escapeSequences_2022KR,
UPRV_LENGTHOF(escapeSequences_2022KR));
results->set(textIn, this, confidence);
return (confidence > 0);
}
CharsetRecog_2022CN::~CharsetRecog_2022CN() {}
const char *CharsetRecog_2022CN::getName() const {
return "ISO-2022-CN";
}
UBool CharsetRecog_2022CN::match(InputText *textIn, CharsetMatch *results) const {
int32_t confidence = match_2022(textIn->fInputBytes,
textIn->fInputLen,
escapeSequences_2022CN,
UPRV_LENGTHOF(escapeSequences_2022CN));
results->set(textIn, this, confidence);
return (confidence > 0);
}
#endif
CharsetRecog_2022::~CharsetRecog_2022() {
// nothing to do
}
U_NAMESPACE_END
#endif
|
