intl/icu/source/i18n/csr2022.cpp@6474c204b198
intl/icu/source/i18n/csr2022.cpp
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
1 /*
2 **********************************************************************
3 * Copyright (C) 2005-2012, International Business Machines
4 * Corporation and others. All Rights Reserved.
5 **********************************************************************
6 */
8 #include "unicode/utypes.h"
10 #if !UCONFIG_NO_CONVERSION
12 #include "cstring.h"
14 #include "csr2022.h"
15 #include "csmatch.h"
17 U_NAMESPACE_BEGIN
19 #define ARRAY_SIZE(array) (sizeof array / sizeof array[0])
21 /**
22 * Matching function shared among the 2022 detectors JP, CN and KR
23 * Counts up the number of legal and unrecognized escape sequences in
24 * the sample of text, and computes a score based on the total number &
25 * the proportion that fit the encoding.
26 *
27 *
28 * @param text the byte buffer containing text to analyse
29 * @param textLen the size of the text in the byte.
30 * @param escapeSequences the byte escape sequences to test for.
31 * @return match quality, in the range of 0-100.
32 */
33 int32_t CharsetRecog_2022::match_2022(const uint8_t *text, int32_t textLen, const uint8_t escapeSequences[][5], int32_t escapeSequences_length) const
34 {
35 int32_t i, j;
36 int32_t escN;
37 int32_t hits = 0;
38 int32_t misses = 0;
39 int32_t shifts = 0;
40 int32_t quality;
42 i = 0;
43 while(i < textLen) {
44 if(text[i] == 0x1B) {
45 escN = 0;
46 while(escN < escapeSequences_length) {
47 const uint8_t *seq = escapeSequences[escN];
48 int32_t seq_length = (int32_t)uprv_strlen((const char *) seq);
50 if (textLen-i >= seq_length) {
51 j = 1;
52 while(j < seq_length) {
53 if(seq[j] != text[i+j]) {
54 goto checkEscapes;
55 }
57 j += 1;
58 }
60 hits += 1;
61 i += seq_length-1;
62 goto scanInput;
63 }
64 // else we ran out of string to compare this time.
65 checkEscapes:
66 escN += 1;
67 }
69 misses += 1;
70 }
72 if( text[i]== 0x0e || text[i] == 0x0f){
73 shifts += 1;
74 }
76 scanInput:
77 i += 1;
78 }
80 if (hits == 0) {
81 return 0;
82 }
84 //
85 // Initial quality is based on relative proportion of recongized vs.
86 // unrecognized escape sequences.
87 // All good: quality = 100;
88 // half or less good: quality = 0;
89 // linear inbetween.
90 quality = (100*hits - 100*misses) / (hits + misses);
92 // Back off quality if there were too few escape sequences seen.
93 // Include shifts in this computation, so that KR does not get penalized
94 // for having only a single Escape sequence, but many shifts.
95 if (hits+shifts < 5) {
96 quality -= (5-(hits+shifts))*10;
97 }
99 if (quality < 0) {
100 quality = 0;
101 }
103 return quality;
104 }
107 static const uint8_t escapeSequences_2022JP[][5] = {
108 {0x1b, 0x24, 0x28, 0x43, 0x00}, // KS X 1001:1992
109 {0x1b, 0x24, 0x28, 0x44, 0x00}, // JIS X 212-1990
110 {0x1b, 0x24, 0x40, 0x00, 0x00}, // JIS C 6226-1978
111 {0x1b, 0x24, 0x41, 0x00, 0x00}, // GB 2312-80
112 {0x1b, 0x24, 0x42, 0x00, 0x00}, // JIS X 208-1983
113 {0x1b, 0x26, 0x40, 0x00, 0x00}, // JIS X 208 1990, 1997
114 {0x1b, 0x28, 0x42, 0x00, 0x00}, // ASCII
115 {0x1b, 0x28, 0x48, 0x00, 0x00}, // JIS-Roman
116 {0x1b, 0x28, 0x49, 0x00, 0x00}, // Half-width katakana
117 {0x1b, 0x28, 0x4a, 0x00, 0x00}, // JIS-Roman
118 {0x1b, 0x2e, 0x41, 0x00, 0x00}, // ISO 8859-1
119 {0x1b, 0x2e, 0x46, 0x00, 0x00} // ISO 8859-7
120 };
122 static const uint8_t escapeSequences_2022KR[][5] = {
123 {0x1b, 0x24, 0x29, 0x43, 0x00}
124 };
126 static const uint8_t escapeSequences_2022CN[][5] = {
127 {0x1b, 0x24, 0x29, 0x41, 0x00}, // GB 2312-80
128 {0x1b, 0x24, 0x29, 0x47, 0x00}, // CNS 11643-1992 Plane 1
129 {0x1b, 0x24, 0x2A, 0x48, 0x00}, // CNS 11643-1992 Plane 2
130 {0x1b, 0x24, 0x29, 0x45, 0x00}, // ISO-IR-165
131 {0x1b, 0x24, 0x2B, 0x49, 0x00}, // CNS 11643-1992 Plane 3
132 {0x1b, 0x24, 0x2B, 0x4A, 0x00}, // CNS 11643-1992 Plane 4
133 {0x1b, 0x24, 0x2B, 0x4B, 0x00}, // CNS 11643-1992 Plane 5
134 {0x1b, 0x24, 0x2B, 0x4C, 0x00}, // CNS 11643-1992 Plane 6
135 {0x1b, 0x24, 0x2B, 0x4D, 0x00}, // CNS 11643-1992 Plane 7
136 {0x1b, 0x4e, 0x00, 0x00, 0x00}, // SS2
137 {0x1b, 0x4f, 0x00, 0x00, 0x00}, // SS3
138 };
140 CharsetRecog_2022JP::~CharsetRecog_2022JP() {}
142 const char *CharsetRecog_2022JP::getName() const {
143 return "ISO-2022-JP";
144 }
146 UBool CharsetRecog_2022JP::match(InputText *textIn, CharsetMatch *results) const {
147 int32_t confidence = match_2022(textIn->fInputBytes,
148 textIn->fInputLen,
149 escapeSequences_2022JP,
150 ARRAY_SIZE(escapeSequences_2022JP));
151 results->set(textIn, this, confidence);
152 return (confidence > 0);
153 }
155 CharsetRecog_2022KR::~CharsetRecog_2022KR() {}
157 const char *CharsetRecog_2022KR::getName() const {
158 return "ISO-2022-KR";
159 }
161 UBool CharsetRecog_2022KR::match(InputText *textIn, CharsetMatch *results) const {
162 int32_t confidence = match_2022(textIn->fInputBytes,
163 textIn->fInputLen,
164 escapeSequences_2022KR,
165 ARRAY_SIZE(escapeSequences_2022KR));
166 results->set(textIn, this, confidence);
167 return (confidence > 0);
168 }
170 CharsetRecog_2022CN::~CharsetRecog_2022CN() {}
172 const char *CharsetRecog_2022CN::getName() const {
173 return "ISO-2022-CN";
174 }
176 UBool CharsetRecog_2022CN::match(InputText *textIn, CharsetMatch *results) const {
177 int32_t confidence = match_2022(textIn->fInputBytes,
178 textIn->fInputLen,
179 escapeSequences_2022CN,
180 ARRAY_SIZE(escapeSequences_2022CN));
181 results->set(textIn, this, confidence);
182 return (confidence > 0);
183 }
185 CharsetRecog_2022::~CharsetRecog_2022() {
186 // nothing to do
187 }
189 U_NAMESPACE_END
190 #endif
