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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166
|
/* Copyright (C) 2004-2024 J.F.Dockes
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the
* Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "autoconfig.h"
#include <assert.h>
#include <stdlib.h>
#include <iostream>
#include <string>
#include <algorithm>
#include <cstring>
#include <unordered_set>
#include "textsplit.h"
// #define LOGGER_LOCAL_LOGINC 3
#include "log.h"
//#define UTF8ITER_CHECK
#include "utf8iter.h"
#include "uproplist.h"
#include "smallut.h"
#include "rclconfig.h"
#include "cjksplitter.h"
#include "kosplitter.h"
#include "cnsplitter.h"
using namespace std;
// Splitting a text into words. The code in this file works with utf-8 in a semi-clean way (see
// uproplist.h). Ascii still gets special treatment in the sense that many special characters can
// only be ascii (e.g. @, _,...). However, this compromise works quite well while being much more
// light-weight than a full-blown Unicode approach (ICU...)
// Decide if we treat katakana as western scripts, splitting into words instead of n-grams. This is
// not absurd (katakana is a kind of alphabet, albeit phonetic and syllabic and is mostly used to
// transcribe western words), but it does not work well because japanese uses separator-less
// compound katakana words, and because the plural terminaisons are irregular and would need a
// specialized stemmer. So we for now process katakana as the rest of cjk, using ngrams. This would
// change if we used an external "intelligent" segmenter like is possible for Hangul. Then Katakana
// processing would depend on the configuration and not a hard ifdef.
#undef KATAKANA_AS_WORDS
// Same for Korean syllabic, and same problem. However we have a runtime option to use an external
// text analyser for Hangul, so this is defined at compile time.
#define HANGUL_AS_WORDS
// Same for Chinese, we may use an external Jieba text segmenter.
// https://github.com/fxsjy/jieba
#define CHINESE_AS_WORDS
// ASCII character classes: we have three main groups, and then some chars are their own class
// because they want special handling.
//
// We have an array with 256 slots where we keep the character types.
// The array could be fully static, but we use a small function to fill it once.
// The array is actually a remnant of the original version which did no utf8.
// Only the lower 127 slots are now used, but keep it at 256 because it makes some tests in the code
// simpler.
const unsigned int charclasses_size = 256;
static int charclasses[charclasses_size];
bool TextSplit::o_processCJK{true};
int TextSplit::o_CJKNgramLen{2};
bool TextSplit::o_noNumbers{false};
bool TextSplit::o_deHyphenate{false};
// Max word size in Unicode characters
int TextSplit::o_maxWordLength{40};
int TextSplit::o_maxWordsInSpan{6};
// Do we produce spans like 12-34-56?
bool TextSplit::o_numberDashSpans{false};
static std::unordered_set<unsigned int> o_idxpunct;
static bool o_haveidxpunct;
static bool o_exthangultagger{false};
static bool o_extchinesetagger{false};
// This is changed to 0 if _ is processed as a letter
static char underscoreatend = '_';
void TextSplit::staticConfInit(RclConfig *config)
{
config->getConfParam("maxtermlength", &o_maxWordLength);
config->getConfParam("maxwordsinspan", &o_maxWordsInSpan);
config->getConfParam("numberdashspans", &o_numberDashSpans);
std::string sidxpunct;
config->getConfParam("indexedpunctuation", sidxpunct);
if (!sidxpunct.empty()) {
Utf8Iter it(sidxpunct);
for (; !it.eof() && !it.error(); it++) {
o_idxpunct.insert(*it);
}
o_haveidxpunct = true;
}
bool bvalue{false};
if (config->getConfParam("nocjk", &bvalue) && bvalue == true) {
o_processCJK = false;
} else {
o_processCJK = true;
int ngramlen;
if (config->getConfParam("cjkngramlen", &ngramlen)) {
o_CJKNgramLen = ngramlen <= CJKSplitter::max_ngramlen() ?
ngramlen : CJKSplitter::max_ngramlen();
}
}
bvalue = false;
if (config->getConfParam("nonumbers", &bvalue)) {
o_noNumbers = bvalue;
}
bvalue = false;
if (config->getConfParam("dehyphenate", &bvalue)) {
o_deHyphenate = bvalue;
}
// Note: charclasses is already initialized (by a static initializer). \ is set as "special"
bvalue = false;
if (config->getConfParam("backslashasletter", &bvalue)) {
if (bvalue) {
charclasses[int('\\')] = A_LLETTER;
}
}
bvalue = false;
if (config->getConfParam("underscoreasletter", &bvalue)) {
if (bvalue) {
charclasses[int('_')] = A_LLETTER;
underscoreatend = 0;
}
}
string kotagger;
config->getConfParam("hangultagger", kotagger);
if (!kotagger.empty()) {
o_exthangultagger = true;
koStaticConfInit(config, kotagger);
}
string chinesetagger;
config->getConfParam("chinesetagger", chinesetagger);
if (!chinesetagger.empty()) {
o_extchinesetagger = true;
cnStaticConfInit(config, chinesetagger);
}
}
// Non-ASCII UTF-8 characters are handled with sets holding all characters with interesting
// properties. This is far from full-blown management of Unicode properties, but seems to do the job
// well enough in most common cases
static vector<unsigned int> vpuncblocks;
static std::unordered_set<unsigned int> spunc;
static std::unordered_set<unsigned int> visiblewhite;
static std::unordered_set<unsigned int> sskip;
class CharClassInit {
public:
CharClassInit() {
unsigned int i;
// Set default value for all: SPACE. Only the low 127 slots are used of course, but it seems
// that having the full 256 makes some tests simpler (not checked recently).
for (i = 0 ; i < 256 ; i ++)
charclasses[i] = TextSplit::SPACE;
char digits[] = "0123456789";
for (i = 0; i < strlen(digits); i++)
charclasses[int(digits[i])] = TextSplit::DIGIT;
char upper[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
for (i = 0; i < strlen(upper); i++)
charclasses[int(upper[i])] = TextSplit::A_ULETTER;
char lower[] = "abcdefghijklmnopqrstuvwxyz";
for (i = 0; i < strlen(lower); i++)
charclasses[int(lower[i])] = TextSplit::A_LLETTER;
char wild[] = "*?[]";
for (i = 0; i < strlen(wild); i++)
charclasses[int(wild[i])] = TextSplit::WILD;
// Characters with special treatment:
//
// The first ones are mostly span-constructing "glue"
// characters, for example those typically allowing us to
// search for an email address as a whole (bob@isp.org instead
// of as a phrase "bob isp org"
//
// The case of the minus sign is a complicated one. It went
// from glue to non-glue to glue along Recoll versions.
// See minus-hyphen-dash.txt in doc/notes
char special[] = ".@+-#'_\n\r\f";
for (i = 0; i < strlen(special); i++)
charclasses[int(special[i])] = special[i];
// Non-ASCII Unicode punctuation and white space
for (i = 0; i < sizeof(unipunc) / sizeof(int); i++) {
spunc.insert(unipunc[i]);
}
spunc.insert((unsigned int)-1);
for (i = 0; i < sizeof(unipuncblocks) / sizeof(int); i++) {
vpuncblocks.push_back(unipuncblocks[i]);
}
assert((vpuncblocks.size() % 2) == 0);
for (i = 0; i < sizeof(avsbwht) / sizeof(int); i++) {
visiblewhite.insert(avsbwht[i]);
}
for (i = 0; i < sizeof(uniskip) / sizeof(int); i++) {
sskip.insert(uniskip[i]);
}
}
};
static const CharClassInit charClassInitInstance;
static inline bool isvisiblewhite(int c)
{
return visiblewhite.find(c) != visiblewhite.end();
}
// Character class: if we do not find it to be special, process as letter.
int TextSplit::whatcc(unsigned int c)
{
if (c <= 127) {
return charclasses[c];
} else {
if (c == 0x2010 || c == 0x2019 || c == 0x275c || c == 0x02bc) {
return c;
} else if (sskip.find(c) != sskip.end()) {
return SKIP;
} else if (spunc.find(c) != spunc.end()) {
return SPACE;
} else {
auto it = lower_bound(vpuncblocks.begin(), vpuncblocks.end(), c);
if (it == vpuncblocks.end())
return LETTER;
if (c == *it)
return SPACE;
if ((it - vpuncblocks.begin()) % 2 == 1) {
return SPACE;
} else {
return LETTER;
}
}
}
}
// Chinese, Japanese, Korean Unicode character ranges. CJK text is generally indexed using an n-gram
// method.
// Exceptions:
// Hangul: we can use an external text linguistic-aware segmenter.
// Chinese: same. Using Jieba
// Katakana: not successful for now. n-grams.
//
// 1100..11FF; Hangul Jamo (optional: see UNICODE_IS_HANGUL)
// 2E80..2EFF; CJK Radicals Supplement
// 3000..303F; CJK Symbols and Punctuation
// 3040..309F; Hiragana
// 30A0..30FF; Katakana
// 3100..312F; Bopomofo
// 3130..318F; Hangul Compatibility Jamo (optional: see UNICODE_IS_HANGUL)
// 3190..319F; Kanbun
// 31A0..31BF; Bopomofo Extended
// 31C0..31EF; CJK Strokes
// 31F0..31FF; Katakana Phonetic Extensions
// 3200..32FF; Enclosed CJK Letters and Months
// 3300..33FF; CJK Compatibility
// 3400..4DBF; CJK Unified Ideographs Extension A
// 4DC0..4DFF; Yijing Hexagram Symbols
// 4E00..9FFF; CJK Unified Ideographs
// A700..A71F; Modifier Tone Letters
// AC00..D7AF; Hangul Syllables (optional: see UNICODE_IS_HANGUL)
// F900..FAFF; CJK Compatibility Ideographs
// FE30..FE4F; CJK Compatibility Forms
// FF00..FFEF; Halfwidth and Fullwidth Forms
// 20000..2A6DF; CJK Unified Ideographs Extension B
// 2F800..2FA1F; CJK Compatibility Ideographs Supplement
#define UNICODE_IS_CJK(p) \
(((p) >= 0x1100 && (p) <= 0x11FF) || \
((p) >= 0x2E80 && (p) <= 0x2EFF) || \
((p) >= 0x3000 && (p) <= 0x9FFF) || \
((p) >= 0xA700 && (p) <= 0xA71F) || \
((p) >= 0xAC00 && (p) <= 0xD7AF) || \
((p) >= 0xF900 && (p) <= 0xFAFF) || \
((p) >= 0xFE30 && (p) <= 0xFE4F) || \
((p) >= 0xFF00 && (p) <= 0xFFEF) || \
((p) >= 0x20000 && (p) <= 0x2A6DF) || \
((p) >= 0x2F800 && (p) <= 0x2FA1F))
// We should probably map 'fullwidth ascii variants' and 'halfwidth
// katakana variants' to something else. Look up "Kuromoji" Lucene
// filter, KuromojiNormalizeFilter.java
// 309F is Hiragana.
#define UNICODE_IN_KATAKANA_RANGE(p) \
((p) != 0x309F && \
(((p) >= 0x3099 && (p) <= 0x30FF) || \
((p) >= 0x31F0 && (p) <= 0x31FF)))
#ifdef KATAKANA_AS_WORDS
#define UNICODE_IS_KATAKANA(p) UNICODE_IN_KATAKANA_RANGE(p)
#else
#define UNICODE_IS_KATAKANA(p) false
#endif
// Hangul ranges and options. If no external tagger is configured, we process HANGUL as generic CJK
// (n-grams): IS_HANGUL will be false and IS_CJK true.
#define UNICODE_IN_HANGUL_RANGE(p) \
(((p) >= 0x1100 && (p) <= 0x11FF) || \
((p) >= 0x3130 && (p) <= 0x318F) || \
((p) >= 0x3200 && (p) <= 0x321e) || \
((p) >= 0x3248 && (p) <= 0x327F) || \
((p) >= 0x3281 && (p) <= 0x32BF) || \
((p) >= 0xAC00 && (p) <= 0xD7AF))
#ifdef HANGUL_AS_WORDS
#define UNICODE_IS_HANGUL(p) (o_exthangultagger && UNICODE_IN_HANGUL_RANGE(p))
#else
#define UNICODE_IS_HANGUL(p) false
#endif
// Chinese ranges: everything in CJK range defined above which is not Katakana or Hangul
#define UNICODE_IN_CHINESE_RANGE(p) \
(UNICODE_IS_CJK(p) && !(UNICODE_IN_KATAKANA_RANGE(p) || UNICODE_IN_HANGUL_RANGE(p)))
#ifdef CHINESE_AS_WORDS
// If we are not using an external text splitter, IS_CJK will be true and IS_CHINESE false
#define UNICODE_IS_CHINESE(p) (o_extchinesetagger && UNICODE_IN_CHINESE_RANGE(p))
#else
#define UNICODE_IS_CHINESE(p) false
#endif
// Tibetan. For now, uses n-grams. Not CJK though so handled a bit differently (because not in the
// big CJK range)
#define UNICODE_IN_TIBETAN_RANGE(p) \
((p) > 0x0f00 && (p) <= 0x0fff)
#define UNICODE_IS_TIBETAN(p) UNICODE_IN_TIBETAN_RANGE(p)
// Thai and Lao range are contiguous
#define UNICODE_IN_THAI_LAO_RANGE(p) \
((p) > 0x0e00 && (p) <= 0x0eff)
#define UNICODE_IS_THAI_OR_LAO(p) UNICODE_IN_THAI_LAO_RANGE(p)
// Burmese
#define UNICODE_IN_BURMESE_RANGE(p) \
((p) > 0x1000 && (p) <= 0x109f)
#define UNICODE_IS_BURMESE(p) UNICODE_IN_BURMESE_RANGE(p)
// Non CJK scripts processed as ngrams
#define UNICODE_IS_OTHER_NGRAM(p) (UNICODE_IS_TIBETAN(p) || UNICODE_IS_THAI_OR_LAO(p) || \
UNICODE_IS_BURMESE(p))
// Just for testing the ngram splitter: this European reader finds it easier to look at results when
// using a simple A-Z range.
#define UNICODE_IN_TESTNGRAM_RANGE(p) \
((p) >= 'A' && (p) <= 'B')
#ifdef TESTING_NGRAMS
#define UNICODE_IS_TESTNGRAM(p) UNICODE_IN_TESTNGRAM_RANGE(p)
#else
#define UNICODE_IS_TESTNGRAM(p) false
#endif
bool TextSplit::isSpace(int c)
{
return whatcc(c) == SPACE;
}
bool TextSplit::isCJK(int c)
{
return UNICODE_IS_CJK(c);
}
bool TextSplit::noStemming(int c)
{
return UNICODE_IS_CJK(c) || UNICODE_IS_OTHER_NGRAM(c);
}
bool TextSplit::isKATAKANA(int c)
{
PRETEND_USE(c);
return UNICODE_IS_KATAKANA(c);
}
bool TextSplit::isHANGUL(int c)
{
PRETEND_USE(c);
return UNICODE_IS_HANGUL(c);
}
bool TextSplit::isCHINESE(int c)
{
PRETEND_USE(c);
return UNICODE_IS_CHINESE(c);
}
bool TextSplit::isNGRAMMED(int c)
{
return UNICODE_IS_OTHER_NGRAM(c) || UNICODE_IS_TESTNGRAM(c) ||
(UNICODE_IS_CJK(c) && !UNICODE_IS_KATAKANA(c) && !UNICODE_IS_HANGUL(c) &&
!UNICODE_IS_CHINESE(c));
}
// This is used to detect katakana/other transitions, which must trigger a word split (there is not
// always a separator, and katakana is otherwise treated like other, in the same routine, unless CJK
// which has its span reader causing a word break)
enum CharSpanClass {CSC_OTHER, CSC_HANGUL, CSC_CHINESE, CSC_CJK, CSC_KATAKANA, CSC_OTHERNGRAM,
CSC_TESTNGRAM};
std::vector<CharFlags> csc_names {
CHARFLAGENTRY(CSC_HANGUL), CHARFLAGENTRY(CSC_CHINESE), CHARFLAGENTRY(CSC_CJK),
CHARFLAGENTRY(CSC_KATAKANA), CHARFLAGENTRY(CSC_OTHER), CHARFLAGENTRY(CSC_OTHERNGRAM),
CHARFLAGENTRY(CSC_TESTNGRAM)};
// Final term checkpoint: do some checking (the kind which is simpler to do here than in the main
// loop), then send term to our client.
inline bool TextSplit::emitterm(bool isspan, const string& w, int pos, size_t btstart, size_t btend)
{
LOGDEB2("TextSplit::emitterm: [" << w << "] pos " << pos << "\n");
#ifdef TEXTSPLIT_STATS
// Update word length statistics. Do this before we filter out
// long words because stats are used to detect bad text
if (!isspan || m_wordLen == m_span.length())
m_stats.newsamp(m_wordChars);
#else
PRETEND_USE(isspan);
#endif
// If the size in bytes is > max size in unicode chars, compute the Unicode length.
// The bytes test saves a bit of CPU as most words will skip the unicode test.
// In theory we know the character size, but in practise, it was lost somewhere in the maze.
if (w.size() == 0 || w.size() >= (size_t)o_maxWordLength) {
int l = utf8len(w);
if (l == 0 || l > o_maxWordLength) {
discarded(w, pos, btstart, btend, WORD_TOO_LONG);
return true;
}
}
if (w.size() == 1) {
// 1 byte word: we index single ASCII letters and digits, but nothing else. Why?
unsigned int c = ((unsigned int)w[0]) & 0xff;
if (charclasses[c] != A_ULETTER && charclasses[c] != A_LLETTER && charclasses[c] != DIGIT &&
(!(m_flags & TXTS_KEEPWILD) || charclasses[c] != WILD) ) {
LOGDEB2("TextSplit::emitterm: erasing single letter term " << c << "\n");
return true;
}
}
// Detect doublons. Happens...?
if (pos != m_prevpos || w.size() != m_prevlen) {
bool ret = takeword(w, pos, btstart, btend);
m_prevpos = pos;
m_prevlen = w.size();
return ret;
}
LOGDEB2("TextSplit::emitterm:dup: [" << w << "] pos " << pos << "\n");
return true;
}
// Check for an acronym/abbreviation spelled like I.B.M. This only works with ASCII.
bool TextSplit::span_is_initials(string& initials)
{
LOGDEB1("span_is_initials: wordlen " << m_wordLen << " spanlen " << m_span.length() <<
" span ["<< m_span << "]\n");
if (m_wordLen == m_span.length() || (m_span.length() & 1) ||
m_span.length() <= 2 || m_span.length() > 20) {
return false;
}
// Check odd chars are '.'
for (unsigned int i = 1 ; i < m_span.length(); i += 2) {
if (m_span[i] != '.') {
return false;
}
}
// Check that even chars are letters
for (unsigned int i = 0 ; i < m_span.length(); i += 2) {
int c = m_span[i];
if (!((c >= 'a' && c <= 'z')||(c >= 'A' && c <= 'Z'))) {
return false;
}
}
initials.reserve(m_span.length()/2 + 1);
for (unsigned int i = 0; i < m_span.length(); i += 2) {
initials += m_span[i];
}
return true;
}
// Generate terms from span. Have to take into account the flags: ONLYSPANS, NOSPANS, noNumbers
bool TextSplit::words_from_span(size_t bp)
{
#if 0
std::cerr<<"Span: ["<<m_span<<"] "<<" bp "<<bp<<" w_i_s size: "<<m_words_in_span.size()<<" :";
for (const auto& [beg, nd] : m_words_in_span)
std::cerr << " [" << beg << " " << nd << "] ";
cerr << "\n";
#endif
int spanwords = int(m_words_in_span.size());
// It seems that something like: tv_combo-sample_util.Po@am_quote can get the splitter to call
// doemit with a span of '@' and words_in_span==0, which then causes a crash when accessing
// words_in_span[0] if the stl assertions are active (e.g. Fedora RPM build). Not too sure what
// the right fix would be, but for now, just defend against it
if (spanwords == 0) {
return true;
}
int pos = m_spanpos;
// Byte position of the span start
size_t spboffs = bp - m_span.size();
if (o_deHyphenate && spanwords == 2 && m_span[m_words_in_span[0].second] == '-') {
unsigned int s0 = m_words_in_span[0].first;
unsigned int l0 = m_words_in_span[0].second - m_words_in_span[0].first;
unsigned int s1 = m_words_in_span[1].first;
unsigned int l1 = m_words_in_span[1].second - m_words_in_span[1].first;
string word = m_span.substr(s0, l0) + m_span.substr(s1, l1);
if (l0 && l1)
emitterm(false, word, m_spanpos, spboffs, spboffs + m_words_in_span[1].second);
}
for (int i = 0; i < ((m_flags&TXTS_ONLYSPANS) ? 1 : spanwords); i++) {
int deb = m_words_in_span[i].first;
bool noposinc = m_words_in_span[i].second == deb;
for (int j = ((m_flags&TXTS_ONLYSPANS) ? spanwords-1 : i);
j < ((m_flags&TXTS_NOSPANS) ? i+1 : spanwords);
j++) {
int fin = m_words_in_span[j].second;
if (fin - deb > int(m_span.size()))
break;
if (!emitterm(j != i+1, m_span.substr(deb, fin-deb), pos, spboffs+deb, spboffs+fin))
return false;
}
if (!noposinc)
++pos;
}
return true;
}
// A method called at word boundaries (different places in text_to_words()), to adjust the current
// state of the parser, and possibly generate term(s).
//
// While inside a span (words linked by glue characters), we just keep track of the word boundaries.
//
// Once actual white-space is reached, we get called with spanerase set to true, and we process the
// span, calling words_from_span() to actually compute and emit the terms.
//
// The object flags can modify our behaviour, deciding if we only emit single words (bill, recoll,
// org), only spans (bill@recoll.org), or words and spans (bill@recoll.org, recoll.org, jf,
// recoll...)
//
// @return true if ok, false for error. Splitting should stop in this case.
// @param spanerase Set if the current span is at its end. Process it.
// @param bp The current BYTE position in the stream (it's beyond the current span data).
inline bool TextSplit::doemit(bool spanerase, size_t _bp)
{
int bp = int(_bp);
LOGDEB2("TextSplit::doemit: sper " << spanerase << " bp " << bp <<
" spp " << m_spanpos << " spanwords " << m_words_in_span.size() <<
" wS " << m_wordStart << " wL " << m_wordLen << " inn " <<
m_inNumber << " span [" << m_span << "]\n");
if (m_wordLen) {
// We have a current word. Remember it
if (!(o_noNumbers && m_inNumber)) {
m_words_in_span.push_back({m_wordStart, m_wordStart + m_wordLen});
m_wordpos++;
}
if (int(m_words_in_span.size()) >= o_maxWordsInSpan) {
// Limit max span word count
spanerase = true;
discarded(m_span, m_spanpos, m_words_in_span[0].first, m_words_in_span.back().second,
LONG_SPAN_TRUNCATED);
}
m_wordLen = m_wordChars = 0;
}
if (!spanerase) {
// Not done with this span. Just update relative word start offset.
m_wordStart = int(m_span.length());
return true;
}
// Span is done (too long or span-terminating character). Produce terms and reset it.
string initials;
if (span_is_initials(initials)) {
if (!emitterm(false, initials, m_spanpos, bp - m_span.length(), bp))
return false;
}
if (!words_from_span(bp)) {
return false;
}
discardspan();
return true;
}
void TextSplit::discardspan()
{
m_span.clear();
m_words_in_span.clear();
m_spanpos = m_wordpos;
m_wordStart = 0;
m_wordLen = m_wordChars = 0;
}
static inline bool isalphanum(int what, unsigned int flgs)
{
return what == TextSplit::A_LLETTER || what == TextSplit::A_ULETTER ||
what == TextSplit::DIGIT || what == TextSplit::LETTER ||
((flgs & TextSplit::TXTS_KEEPWILD) && what == TextSplit::WILD);
}
static inline bool isdigit(int what, unsigned int flgs)
{
return what == TextSplit::DIGIT || ((flgs & TextSplit::TXTS_KEEPWILD)&& what == TextSplit::WILD);
}
#ifdef TEXTSPLIT_STATS
#define STATS_INC_WORDCHARS ++m_wordChars
#else
#define STATS_INC_WORDCHARS
#endif
vector<CharFlags> splitFlags{
{TextSplit::TXTS_NOSPANS, "nospans"},
{TextSplit::TXTS_ONLYSPANS, "onlyspans"},
{TextSplit::TXTS_KEEPWILD, "keepwild"}
};
TextSplit::TextSplit(int flags)
: m_flags(flags)
{
}
TextSplit::~TextSplit()
{
}
// Splitting a text into terms to be indexed.
//
// We mostly emit a word every time we see a separator, but some chars are handled specially so that
// special cases, ie, c++, jfd@recoll.org etc, are handled properly.
//
// Esp. we generate "spans". e.g. jfd@recoll.org, in addition to the individual words. This was
// quite useful with old Xapian versions, which were slow with frequent word phrase searches
// (e.g. the com in .com). This is not so useful now because Xapian performance has much improved,
// but, it does not hurt much either, as these "spans" are infrequent in real text.
bool TextSplit::text_to_words(const string &in)
{
LOGDEB1("TextSplit::text_to_words: docjk " << o_processCJK << "(" <<
o_CJKNgramLen << ") " << flagsToString(splitFlags, m_flags) <<
" [" << in.substr(0,50) << "]\n");
if (in.empty())
return true;
// Reset the data members relative to splitting state
clearsplitstate();
bool pagepending = false;
bool nlpending = false;
bool softhyphenpending = false;
Utf8Iter it(in);
#if defined(KATAKANA_AS_WORDS) || defined(HANGUL_AS_WORDS) || defined(CHINESE_AS_WORDS)
int prev_csc = -1;
#endif
int prevc = -1;
for (; !it.eof() && !it.error(); it++) {
unsigned int c = *it;
if (c == (unsigned int)-1) {
LOGERR("Textsplit: error occurred while scanning UTF-8 string\n");
return false;
}
CharSpanClass csc;
// General logic here: UNICODE_IS_CJK is always true for CJK characters and must be tested
// last. UNICODE_IS_whatever will be true if the character belongs to the appropriate
// segment AND a specific processor (e.g. external Hangul word segmenter) has been
// configured. In other words, CJK characters are processed by the generic ngram term
// generator, except if a language-specific processor has been implemented and configured.
bool gospecial = true;
if (UNICODE_IS_KATAKANA(c)) {
csc = CSC_KATAKANA;
} else if (UNICODE_IS_HANGUL(c)) {
csc = CSC_HANGUL;
} else if (UNICODE_IS_CHINESE(c)) {
csc = CSC_CHINESE;
} else if (UNICODE_IS_OTHER_NGRAM(c)) {
csc = CSC_OTHERNGRAM;
} else if (UNICODE_IS_TESTNGRAM(c)) {
csc = CSC_TESTNGRAM;
} else if (UNICODE_IS_CJK(c)) {
csc = CSC_CJK;
} else {
gospecial = false;
csc = CSC_OTHER;
}
if (o_processCJK && gospecial) {
// Using ngrams with possible exceptions for Hangul and Chinese if so configured.
// Do like at EOF with the current non-cjk data.
if (m_wordLen || m_span.length()) {
if (!doemit(true, it.getBpos()))
return false;
}
// Hand off situation to the appropriate routine.
if (csc == CSC_HANGUL) {
// Note: at the moment, the real ko splitter is a lock-protected singleton which is
// why we just recreate it here: no real initialisation.
KOSplitter splt(*this);
if (!splt.text_to_words(it, &c, m_wordpos)) {
LOGERR("Textsplit: scan error in korean handler\n");
return false;
}
} else if (csc == CSC_CHINESE) {
if (!m_cnsplitter) {
m_cnsplitter = std::make_unique<CNSplitter>(*this);
}
if (!m_cnsplitter->text_to_words(it, &c, m_wordpos)) {
LOGERR("Textsplit: scan error in chinese handler\n");
return false;
}
} else {
CJKSplitter splt(*this, o_CJKNgramLen);
if (!splt.text_to_words(it, &c, m_wordpos)) {
LOGERR("Textsplit: scan error in cjk handler\n");
return false;
}
}
// Reset state, saving term position, and return the found non-cjk
// unicode character value. The current input byte offset is kept
// in the utf8Iter
int pos = m_wordpos;
clearsplitstate();
m_spanpos = m_wordpos = pos;
// Check for eof, else c contains the first non-cjk
// character after the cjk sequence, just go on.
if (it.eof() || it.error())
break;
}
#if defined(KATAKANA_AS_WORDS) || defined(HANGUL_AS_WORDS) || defined(CHINESE_AS_WORDS)
// Only needed if we have script transitions inside this
// routine, else the call to cjk_to_words does the job (so do
// nothing right after a CJK section). Because
// katakana-western transitions sometimes have no whitespace
// (and maybe hangul too, but probably not).
if (prev_csc != CSC_CJK && prev_csc != CSC_HANGUL && prev_csc != CSC_CHINESE &&
csc != prev_csc && (m_wordLen || m_span.length())) {
LOGDEB2("csc " << valToString(csc_names, csc) << " prev_csc " <<
valToString(csc_names, prev_csc) << " wl " <<
m_wordLen << " spl " << m_span.length() << endl);
if (!doemit(true, it.getBpos())) {
return false;
}
}
prev_csc = csc;
#endif
int cc = whatcc(c);
switch (cc) {
case SKIP:
// Special-case soft-hyphen. To work, this depends on the
// fact that only SKIP calls "continue" inside the
// switch. All the others will do the softhyphenpending
// reset after the switch
if (c == 0xad) {
softhyphenpending = true;
} else {
softhyphenpending = false;
}
// Skips the softhyphenpending reset
continue;
case DIGIT:
if (m_wordLen == 0)
m_inNumber = true;
m_wordLen += it.appendchartostring(m_span);
STATS_INC_WORDCHARS;
break;
case SPACE:
SPACE:
if (m_wordLen || m_span.length()) {
if (!doemit(true, it.getBpos()))
return false;
m_inNumber = false;
}
if (pagepending) {
pagepending = false;
newpage(m_wordpos);
}
if (nlpending) {
nlpending = false;
newline(m_wordpos);
}
if (o_haveidxpunct && (o_idxpunct.find(c) != o_idxpunct.end())) {
std::string tmp;
auto l = it.appendchartostring(tmp);
// std::cerr << "IDXSPACE: [" << c << "] [" << tmp << "]\n";
takeword(tmp, m_wordpos, it.getBpos(), it.getBpos()+l);
if (m_spanpos == m_wordpos)
m_spanpos++;
m_wordpos++;
}
break;
case WILD:
if (m_flags & TXTS_KEEPWILD)
goto NORMALCHAR;
else
goto SPACE;
break;
case '-':
case '+':
if (m_wordLen == 0) {
// + or - don't start a term except if this looks like
// it's going to be to be a number
if (isdigit(whatcc(it[it.getCpos()+1]), m_flags)) {
// -10
m_inNumber = true;
m_wordLen += it.appendchartostring(m_span);
STATS_INC_WORDCHARS;
break;
}
} else if (!o_numberDashSpans && m_inNumber) {
if ((m_span[m_span.length() - 1] == 'e' || m_span[m_span.length() - 1] == 'E')) {
if (isdigit(whatcc(it[it.getCpos()+1]), m_flags)) {
m_wordLen += it.appendchartostring(m_span);
STATS_INC_WORDCHARS;
break;
}
}
} else {
int nextc = it[it.getCpos()+1];
if (cc == '+') {
if ((nextc == '+' && prevc != '+') ||
(prevc == '+' && (nextc == -1 || isvisiblewhite(nextc)))) {
// someword++ but not someword+ or someword+++
m_wordLen += it.appendchartostring(m_span);
STATS_INC_WORDCHARS;
break;
}
} else {
// Note about dangling hyphens: we always strip '-' found before whitespace,
// even before a newline, then generate two terms, before and after the line
// break. We have no way to know if '-' is there because a word was broken by
// justification or if it was part of an actual compound word (would need a
// dictionary to check). As soft-hyphen *should* be used if the '-' is not part
// of the text.
if (nextc == -1 || isvisiblewhite(nextc)) {
goto SPACE;
}
if (!doemit(false, it.getBpos()))
return false;
m_inNumber = false;
m_wordStart += it.appendchartostring(m_span);
break;
}
}
goto SPACE;
case '.':
{
// Need a little lookahead here. At worse this gets the end null
int nextc = it[it.getCpos()+1];
int nextwhat = whatcc(nextc);
if (m_inNumber) {
if (!isdigit(nextwhat, m_flags))
goto SPACE;
m_wordLen += it.appendchartostring(m_span);
STATS_INC_WORDCHARS;
break;
} else {
// Found '.' while not in number
// Only letters and digits make sense after
if (!isalphanum(nextwhat, m_flags)) {
// Do append the dot to the span: for abbrev recognition.
it.appendchartostring(m_span);
// Set the iterator to point to the look-ahead char. Need to
// test for nl/newpage here (there should be a better way?)
it++;
if (*it == '\n')
nlpending = true;
else if (*it == '\f')
pagepending = true;
goto SPACE;
}
// Keep an initial '.' for catching .net, and .34 (aka
// 0.34) but this adds quite a few spurious terms !
if (m_span.length() == 0) {
// Check for number like .1
if (isdigit(nextwhat, m_flags)) {
m_inNumber = true;
m_wordLen += it.appendchartostring(m_span);
} else {
m_words_in_span.push_back(pair<int,int>(m_wordStart, m_wordStart));
m_wordStart += it.appendchartostring(m_span);
}
STATS_INC_WORDCHARS;
break;
}
// '.' between words: span glue
if (m_wordLen) {
if (!doemit(false, it.getBpos()))
return false;
m_wordStart += it.appendchartostring(m_span);
}
}
}
break;
case 0x2010: // hyphen
case 0x2019: // variations on single quote
case 0x275c:
case 0x02bc:
case '@':
case '_': // If underscoreasletter is set, we'll never get this
case '\'':
{
// If in word, potential span: o'brien, jf@dockes.org, else treat as SPACE
int nextc = it[it.getCpos()+1];
if (nextc == -1 || isvisiblewhite(nextc)) {
goto SPACE;
}
if (m_wordLen) {
if (!doemit(false, it.getBpos()))
return false;
m_inNumber = false;
m_wordStart += it.appendchartostring(m_span);
}
}
break;
case '#': {
int w = whatcc(it[it.getCpos()+1]);
// Keep it only at the beginning of a word (hashtag),
if (m_wordLen == 0 && isalphanum(w, m_flags)) {
m_wordLen += it.appendchartostring(m_span);
STATS_INC_WORDCHARS;
break;
}
// or at the end (special case for c# ...)
if (m_wordLen > 0) {
if (w == SPACE || w == '\n' || w == '\r') {
m_wordLen += it.appendchartostring(m_span);
STATS_INC_WORDCHARS;
break;
}
}
goto SPACE;
}
break;
case '\n':
nlpending = true;
/* FALLTHROUGH */
case '\r':
if (softhyphenpending) {
// Don't reset soft-hyphen
continue;
} else {
// Normal case: EOL is white space
goto SPACE;
}
break;
case '\f':
pagepending = true;
goto SPACE;
break;
#ifdef RCL_SPLIT_CAMELCASE
// Camelcase handling.
// If we get uppercase ascii after lowercase ascii, emit word.
// This emits "camel" when hitting the 'C' of camelCase
// Not enabled by defaults as this makes phrase searches quite
// confusing.
// ie "MySQL manual" is matched by "MySQL manual" and
// "my sql manual" but not "mysql manual"
// A possibility would be to emit both my and sql at the
// same position. All non-phrase searches would work, and
// both "MySQL manual" and "mysql manual" phrases would
// match too. "my sql manual" would not match, but this is
// not an issue.
case A_ULETTER:
if (m_span.length() &&
charclasses[(unsigned char)m_span[m_span.length() - 1]] ==
A_LLETTER) {
if (m_wordLen) {
if (!doemit(false, it.getBpos()))
return false;
}
}
goto NORMALCHAR;
// CamelCase handling.
// If we get lowercase after uppercase and the current
// word length is bigger than one, it means we had a
// string of several upper-case letters: an
// acronym (readHTML) or a single letter article (ALittleHelp).
// Emit the uppercase word before proceeding
case A_LLETTER:
if (m_span.length() &&
charclasses[(unsigned char)m_span[m_span.length() - 1]] ==
A_ULETTER && m_wordLen > 1) {
// Multiple upper-case letters. Single letter word
// or acronym which we want to emit now
m_wordLen--;
if (!doemit(false, it.getBpos()))
return false;
// m_wordstart could be 0 here if the span was reset
// for excessive length
if (m_wordStart)
m_wordStart--;
m_wordLen++;
}
goto NORMALCHAR;
#endif /* CAMELCASE */
default:
NORMALCHAR:
if (m_inNumber && c != 'e' && c != 'E') {
m_inNumber = false;
}
m_wordLen += it.appendchartostring(m_span);
STATS_INC_WORDCHARS;
break;
}
softhyphenpending = false;
prevc = cc;
}
if (m_wordLen || m_span.length()) {
if (!doemit(true, it.getBpos()))
return false;
}
return true;
}
// Specialization for countWords
class TextSplitCW : public TextSplit {
public:
int wcnt;
TextSplitCW(int flags) : TextSplit(flags), wcnt(0) {}
bool takeword(const string &, size_t, size_t, size_t) override {
wcnt++;
return true;
}
};
int TextSplit::countWords(const string& s, int flgs)
{
TextSplitCW splitter(flgs);
splitter.text_to_words(s);
return splitter.wcnt;
}
bool TextSplit::hasVisibleWhite(const string &in)
{
Utf8Iter it(in);
for (; !it.eof() && !it.error(); it++) {
unsigned int c = (unsigned char)*it;
if (c == (unsigned int)-1) {
LOGERR("hasVisibleWhite: error while scanning UTF-8 string\n");
return false;
}
if (isvisiblewhite(c))
return true;
}
return false;
}
template <class T> bool u8stringToStrings(const string &s, T &tokens)
{
Utf8Iter it(s);
string current;
tokens.clear();
enum states {SPACE, TOKEN, INQUOTE, ESCAPE};
states state = SPACE;
for (; !it.eof() && !it.error(); it++) {
unsigned int c = *it;
if (visiblewhite.find(c) != visiblewhite.end())
c = ' ';
if (c == (unsigned int)-1) {
LOGERR("TextSplit::stringToStrings: error while scanning UTF-8 "
"string\n");
return false;
}
switch (c) {
case '"':
switch(state) {
case SPACE: state = INQUOTE; continue;
case TOKEN: goto push_char;
case ESCAPE: state = INQUOTE; goto push_char;
case INQUOTE: tokens.push_back(current);current.clear();
state = SPACE; continue;
}
break;
case '\\':
switch(state) {
case SPACE:
case TOKEN: state=TOKEN; goto push_char;
case INQUOTE: state = ESCAPE; continue;
case ESCAPE: state = INQUOTE; goto push_char;
}
break;
case ' ':
case '\t':
case '\n':
case '\r':
switch(state) {
case SPACE: continue;
case TOKEN: tokens.push_back(current); current.clear();
state = SPACE; continue;
case INQUOTE:
case ESCAPE: goto push_char;
}
break;
default:
switch(state) {
case ESCAPE: state = INQUOTE; break;
case SPACE: state = TOKEN; break;
case TOKEN:
case INQUOTE: break;
}
push_char:
it.appendchartostring(current);
}
}
// End of string. Process residue, and possible error (unfinished quote)
switch(state) {
case SPACE: break;
case TOKEN: tokens.push_back(current); break;
case INQUOTE:
case ESCAPE: return false;
}
return true;
}
bool TextSplit::stringToStrings(const string &s, vector<string> &tokens)
{
return u8stringToStrings<vector<string> >(s, tokens);
}
|