1 /* 2 ********************************************************************** 3 * Copyright (C) 2005-2015, International Business Machines 4 * Corporation and others. All Rights Reserved. 5 ********************************************************************** 6 */ 7 8 #include "unicode/utypes.h" 9 10 #if !UCONFIG_NO_CONVERSION 11 12 #include "cstring.h" 13 14 #include "csr2022.h" 15 #include "csmatch.h" 16 17 U_NAMESPACE_BEGIN 18 19 #define ARRAY_SIZE(array) (sizeof array / sizeof array[0]) 20 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; 41 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); 49 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 } 56 57 j += 1; 58 } 59 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 } 68 69 misses += 1; 70 } 71 72 if( text[i]== 0x0e || text[i] == 0x0f){ 73 shifts += 1; 74 } 75 76 scanInput: 77 i += 1; 78 } 79 80 if (hits == 0) { 81 return 0; 82 } 83 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); 91 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 } 98 99 if (quality < 0) { 100 quality = 0; 101 } 102 103 return quality; 104 } 105 106 107 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 }; 121 122 #if !UCONFIG_ONLY_HTML_CONVERSION 123 static const uint8_t escapeSequences_2022KR[][5] = { 124 {0x1b, 0x24, 0x29, 0x43, 0x00} 125 }; 126 127 static const uint8_t escapeSequences_2022CN[][5] = { 128 {0x1b, 0x24, 0x29, 0x41, 0x00}, // GB 2312-80 129 {0x1b, 0x24, 0x29, 0x47, 0x00}, // CNS 11643-1992 Plane 1 130 {0x1b, 0x24, 0x2A, 0x48, 0x00}, // CNS 11643-1992 Plane 2 131 {0x1b, 0x24, 0x29, 0x45, 0x00}, // ISO-IR-165 132 {0x1b, 0x24, 0x2B, 0x49, 0x00}, // CNS 11643-1992 Plane 3 133 {0x1b, 0x24, 0x2B, 0x4A, 0x00}, // CNS 11643-1992 Plane 4 134 {0x1b, 0x24, 0x2B, 0x4B, 0x00}, // CNS 11643-1992 Plane 5 135 {0x1b, 0x24, 0x2B, 0x4C, 0x00}, // CNS 11643-1992 Plane 6 136 {0x1b, 0x24, 0x2B, 0x4D, 0x00}, // CNS 11643-1992 Plane 7 137 {0x1b, 0x4e, 0x00, 0x00, 0x00}, // SS2 138 {0x1b, 0x4f, 0x00, 0x00, 0x00}, // SS3 139 }; 140 #endif 141 142 CharsetRecog_2022JP::~CharsetRecog_2022JP() {} 143 144 const char *CharsetRecog_2022JP::getName() const { 145 return "ISO-2022-JP"; 146 } 147 148 UBool CharsetRecog_2022JP::match(InputText *textIn, CharsetMatch *results) const { 149 int32_t confidence = match_2022(textIn->fInputBytes, 150 textIn->fInputLen, 151 escapeSequences_2022JP, 152 ARRAY_SIZE(escapeSequences_2022JP)); 153 results->set(textIn, this, confidence); 154 return (confidence > 0); 155 } 156 157 #if !UCONFIG_ONLY_HTML_CONVERSION 158 CharsetRecog_2022KR::~CharsetRecog_2022KR() {} 159 160 const char *CharsetRecog_2022KR::getName() const { 161 return "ISO-2022-KR"; 162 } 163 164 UBool CharsetRecog_2022KR::match(InputText *textIn, CharsetMatch *results) const { 165 int32_t confidence = match_2022(textIn->fInputBytes, 166 textIn->fInputLen, 167 escapeSequences_2022KR, 168 ARRAY_SIZE(escapeSequences_2022KR)); 169 results->set(textIn, this, confidence); 170 return (confidence > 0); 171 } 172 173 CharsetRecog_2022CN::~CharsetRecog_2022CN() {} 174 175 const char *CharsetRecog_2022CN::getName() const { 176 return "ISO-2022-CN"; 177 } 178 179 UBool CharsetRecog_2022CN::match(InputText *textIn, CharsetMatch *results) const { 180 int32_t confidence = match_2022(textIn->fInputBytes, 181 textIn->fInputLen, 182 escapeSequences_2022CN, 183 ARRAY_SIZE(escapeSequences_2022CN)); 184 results->set(textIn, this, confidence); 185 return (confidence > 0); 186 } 187 #endif 188 189 CharsetRecog_2022::~CharsetRecog_2022() { 190 // nothing to do 191 } 192 193 U_NAMESPACE_END 194 #endif 195
