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comparison: intl/icu/source/i18n/csr2022.cpp
intl/icu/source/i18n/csr2022.cpp
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| 1 /* | |
| 2 ********************************************************************** | |
| 3 * Copyright (C) 2005-2012, 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 static const uint8_t escapeSequences_2022KR[][5] = { | |
| 123 {0x1b, 0x24, 0x29, 0x43, 0x00} | |
| 124 }; | |
| 125 | |
| 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 }; | |
| 139 | |
| 140 CharsetRecog_2022JP::~CharsetRecog_2022JP() {} | |
| 141 | |
| 142 const char *CharsetRecog_2022JP::getName() const { | |
| 143 return "ISO-2022-JP"; | |
| 144 } | |
| 145 | |
| 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 } | |
| 154 | |
| 155 CharsetRecog_2022KR::~CharsetRecog_2022KR() {} | |
| 156 | |
| 157 const char *CharsetRecog_2022KR::getName() const { | |
| 158 return "ISO-2022-KR"; | |
| 159 } | |
| 160 | |
| 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 } | |
| 169 | |
| 170 CharsetRecog_2022CN::~CharsetRecog_2022CN() {} | |
| 171 | |
| 172 const char *CharsetRecog_2022CN::getName() const { | |
| 173 return "ISO-2022-CN"; | |
| 174 } | |
| 175 | |
| 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 } | |
| 184 | |
| 185 CharsetRecog_2022::~CharsetRecog_2022() { | |
| 186 // nothing to do | |
| 187 } | |
| 188 | |
| 189 U_NAMESPACE_END | |
| 190 #endif |
