17935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert/* 27935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert******************************************************************************* 37935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert* Copyright (C) 2005 - 2012, International Business Machines Corporation and * 47935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert* others. All Rights Reserved. * 57935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert******************************************************************************* 67935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert*/ 77935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubertpackage com.ibm.icu.text; 87935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 97935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert/** 107935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * class CharsetRecog_2022 part of the ICU charset detection imlementation. 117935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * This is a superclass for the individual detectors for 127935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * each of the detectable members of the ISO 2022 family 137935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * of encodings. 147935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * 157935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * The separate classes are nested within this class. 167935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert */ 177935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubertabstract class CharsetRecog_2022 extends CharsetRecognizer { 187935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 197935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 207935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert /** 217935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * Matching function shared among the 2022 detectors JP, CN and KR 227935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * Counts up the number of legal an unrecognized escape sequences in 237935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * the sample of text, and computes a score based on the total number & 247935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * the proportion that fit the encoding. 257935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * 267935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * 277935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * @param text the byte buffer containing text to analyse 287935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * @param textLen the size of the text in the byte. 297935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * @param escapeSequences the byte escape sequences to test for. 307935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert * @return match quality, in the range of 0-100. 317935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert */ 327935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert int match(byte [] text, int textLen, byte [][] escapeSequences) { 337935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert int i, j; 347935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert int escN; 357935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert int hits = 0; 367935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert int misses = 0; 377935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert int shifts = 0; 387935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert int quality; 397935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert scanInput: 407935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert for (i=0; i<textLen; i++) { 417935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert if (text[i] == 0x1b) { 427935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert checkEscapes: 437935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert for (escN=0; escN<escapeSequences.length; escN++) { 447935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert byte [] seq = escapeSequences[escN]; 457935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 467935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert if ((textLen - i) < seq.length) { 477935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert continue checkEscapes; 487935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 497935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 507935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert for (j=1; j<seq.length; j++) { 517935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert if (seq[j] != text[i+j]) { 527935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert continue checkEscapes; 537935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 547935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 557935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 567935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert hits++; 577935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert i += seq.length-1; 587935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert continue scanInput; 597935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 607935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 617935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert misses++; 627935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 637935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 647935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert if (text[i] == 0x0e || text[i] == 0x0f) { 657935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert // Shift in/out 667935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert shifts++; 677935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 687935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 697935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 707935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert if (hits == 0) { 717935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert return 0; 727935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 737935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 747935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert // 757935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert // Initial quality is based on relative proportion of recongized vs. 767935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert // unrecognized escape sequences. 777935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert // All good: quality = 100; 787935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert // half or less good: quality = 0; 797935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert // linear inbetween. 807935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert quality = (100*hits - 100*misses) / (hits + misses); 817935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 827935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert // Back off quality if there were too few escape sequences seen. 837935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert // Include shifts in this computation, so that KR does not get penalized 847935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert // for having only a single Escape sequence, but many shifts. 857935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert if (hits+shifts < 5) { 867935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert quality -= (5-(hits+shifts))*10; 877935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 887935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 897935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert if (quality < 0) { 907935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert quality = 0; 917935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 927935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert return quality; 937935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 947935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 957935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 967935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 977935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 987935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert static class CharsetRecog_2022JP extends CharsetRecog_2022 { 997935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert private byte [] [] escapeSequences = { 1007935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x28, 0x43}, // KS X 1001:1992 1017935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x28, 0x44}, // JIS X 212-1990 1027935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x40}, // JIS C 6226-1978 1037935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x41}, // GB 2312-80 1047935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x42}, // JIS X 208-1983 1057935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x26, 0x40}, // JIS X 208 1990, 1997 1067935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x28, 0x42}, // ASCII 1077935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x28, 0x48}, // JIS-Roman 1087935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x28, 0x49}, // Half-width katakana 1097935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x28, 0x4a}, // JIS-Roman 1107935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x2e, 0x41}, // ISO 8859-1 1117935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x2e, 0x46} // ISO 8859-7 1127935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert }; 1137935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 1147935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert String getName() { 1157935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert return "ISO-2022-JP"; 1167935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 1177935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 1187935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert CharsetMatch match(CharsetDetector det) { 1197935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert int confidence = match(det.fInputBytes, det.fInputLen, escapeSequences); 1207935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert return confidence == 0 ? null : new CharsetMatch(det, this, confidence); 1217935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 1227935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 1237935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 1247935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert static class CharsetRecog_2022KR extends CharsetRecog_2022 { 1257935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert private byte [] [] escapeSequences = { 1267935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x29, 0x43} 1277935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert }; 1287935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 1297935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert String getName() { 1307935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert return "ISO-2022-KR"; 1317935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 1327935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 1337935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert CharsetMatch match(CharsetDetector det) { 1347935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert int confidence = match(det.fInputBytes, det.fInputLen, escapeSequences); 1357935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert return confidence == 0 ? null : new CharsetMatch(det, this, confidence); 1367935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 1377935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 1387935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 1397935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert static class CharsetRecog_2022CN extends CharsetRecog_2022 { 1407935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert private byte [] [] escapeSequences = { 1417935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x29, 0x41}, // GB 2312-80 1427935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x29, 0x47}, // CNS 11643-1992 Plane 1 1437935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x2A, 0x48}, // CNS 11643-1992 Plane 2 1447935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x29, 0x45}, // ISO-IR-165 1457935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x2B, 0x49}, // CNS 11643-1992 Plane 3 1467935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x2B, 0x4A}, // CNS 11643-1992 Plane 4 1477935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x2B, 0x4B}, // CNS 11643-1992 Plane 5 1487935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x2B, 0x4C}, // CNS 11643-1992 Plane 6 1497935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x24, 0x2B, 0x4D}, // CNS 11643-1992 Plane 7 1507935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x4e}, // SS2 1517935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert {0x1b, 0x4f}, // SS3 1527935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert }; 1537935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 1547935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert String getName() { 1557935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert return "ISO-2022-CN"; 1567935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 1577935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 1587935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert CharsetMatch match(CharsetDetector det) { 1597935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert int confidence = match(det.fInputBytes, det.fInputLen, escapeSequences); 1607935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert return confidence == 0 ? null : new CharsetMatch(det, this, confidence); 1617935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 1627935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert } 1637935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 1647935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert} 1657935b1839a081ed19ae0d33029ad3c09632a2caaFredrik Roubert 166