summaryrefslogtreecommitdiffstats
path: root/src/storage/pinyin_parser2.cpp
blob: 081b0695bc4ed9a6619cb20cc07da1cc50f2bd62 (plain)
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
/* 
 *  libpinyin
 *  Library to deal with pinyin.
 *  
 *  Copyright (C) 2011 Peng Wu <alexepico@gmail.com>
 *  
 *  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 "pinyin_parser2.h"
#include <ctype.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include "stl_lite.h"
#include "pinyin_phrase2.h"
#include "pinyin_custom2.h"
#include "chewing_key.h"
#include "pinyin_parser_table.h"
#include "double_pinyin_table.h"
#include "chewing_table.h"


using namespace pinyin;

static bool check_pinyin_options(pinyin_option_t options, const pinyin_index_item_t * item) {
    guint32 flags = item->m_flags;
    assert (flags & IS_PINYIN);

    /* handle incomplete pinyin. */
    if (flags & PINYIN_INCOMPLETE) {
        if (!(options & PINYIN_INCOMPLETE))
            return false;
    }

    /* handle correct pinyin, currently only one flag per item. */
    flags &= PINYIN_CORRECT_ALL;
    options &= PINYIN_CORRECT_ALL;

    if (flags) {
        if ((flags & options) != flags)
            return false;
    }

    return true;
}

static bool check_chewing_options(pinyin_option_t options, const chewing_index_item_t * item) {
    guint32 flags = item->m_flags;
    assert (flags & IS_CHEWING);

    /* handle incomplete chewing. */
    if (flags & CHEWING_INCOMPLETE) {
        if (!(options & CHEWING_INCOMPLETE))
            return false;
    }

    return true;
}


gint ChewingKey::get_table_index() {
    assert(m_initial <  CHEWING_NUMBER_OF_INITIALS);
    assert(m_middle < CHEWING_NUMBER_OF_MIDDLES);
    assert(m_final < CHEWING_NUMBER_OF_FINALS);

    gint index = chewing_key_table[(m_initial * CHEWING_NUMBER_OF_MIDDLES + m_middle) * CHEWING_NUMBER_OF_FINALS + m_final];
    return index == -1 ? 0 : index;
}

gchar * ChewingKey::get_pinyin_string() {
    assert(m_tone < CHEWING_NUMBER_OF_TONES);
    gint index = get_table_index();
    assert(index < G_N_ELEMENTS(content_table));
    const content_table_item_t & item = content_table[index];

    if (CHEWING_ZERO_TONE == m_tone) {
        return g_strdup(item.m_pinyin_str);
    } else {
        return g_strdup_printf("%s%d", item.m_pinyin_str, m_tone);
    }
}

gchar * ChewingKey::get_chewing_string() {
    assert(m_tone < CHEWING_NUMBER_OF_TONES);
    gint index = get_table_index();
    assert(index < G_N_ELEMENTS(content_table));
    const content_table_item_t & item = content_table[index];

    if (CHEWING_ZERO_TONE == m_tone) {
        return g_strdup(item.m_chewing_str);
    } else {
        return g_strdup_printf("%s%s", item.m_chewing_str,
                               chewing_tone_table[m_tone]);
    }
}


/* Pinyin Parsers */

/* internal information for pinyin parsers. */
struct parse_value_t{
    ChewingKey m_key;
    ChewingKeyRest m_key_rest;
    gint16 m_num_keys;
    gint16 m_parsed_len;
    gint16 m_last_step;

    /* constructor */
public:
    parse_value_t(){
        m_num_keys = 0;
        m_parsed_len = 0;
        m_last_step = -1;
    }
};

const guint16 max_full_pinyin_length   = 7;  /* include tone. */

const guint16 max_double_pinyin_length = 3;  /* include tone. */

const guint16 max_chewing_length       = 4;  /* include tone. */

static bool compare_pinyin_less_than(const pinyin_index_item_t & lhs,
                                     const pinyin_index_item_t & rhs){
    return 0 > strcmp(lhs.m_pinyin_input, rhs.m_pinyin_input);
}

static inline bool search_pinyin_index(pinyin_option_t options,
                                       const char * pinyin,
                                       ChewingKey & key){
    pinyin_index_item_t item;
    memset(&item, 0, sizeof(item));
    item.m_pinyin_input = pinyin;

    std_lite::pair<const pinyin_index_item_t *,
                   const pinyin_index_item_t *> range;
    range = std_lite::equal_range
        (pinyin_index, pinyin_index + G_N_ELEMENTS(pinyin_index),
         item, compare_pinyin_less_than);

    guint16 range_len = range.second - range.first;
    assert(range_len <= 1);
    if (range_len == 1) {
        const pinyin_index_item_t * index = range.first;

        if (!check_pinyin_options(options, index))
            return false;

        key = content_table[index->m_table_index].m_chewing_key;
        assert(key.get_table_index() == index->m_table_index);
        return true;
    }

    return false;
}

static bool compare_chewing_less_than(const chewing_index_item_t & lhs,
                                      const chewing_index_item_t & rhs){
    return 0 > strcmp(lhs.m_chewing_input, rhs.m_chewing_input);
}

static inline bool search_chewing_index(pinyin_option_t options,
                                        const char * chewing,
                                        ChewingKey & key){
    chewing_index_item_t item;
    memset(&item, 0, sizeof(item));
    item.m_chewing_input = chewing;

    std_lite::pair<const chewing_index_item_t *,
                   const chewing_index_item_t *> range;
    range = std_lite::equal_range
        (chewing_index, chewing_index + G_N_ELEMENTS(chewing_index),
         item, compare_chewing_less_than);

    guint16 range_len = range.second - range.first;
    assert (range_len <= 1);

    if (range_len == 1) {
        const chewing_index_item_t * index = range.first;

        if (!check_chewing_options(options, index))
            return false;

        key = content_table[index->m_table_index].m_chewing_key;
        assert(key.get_table_index() == index->m_table_index);
        return true;
    }

    return false;
}

/* Full Pinyin Parser */
FullPinyinParser2::FullPinyinParser2 (){
    m_parse_steps = g_array_new(TRUE, FALSE, sizeof(parse_value_t));
}


bool FullPinyinParser2::parse_one_key (pinyin_option_t options,
                                       ChewingKey & key,
                                       const char * pinyin, int len) const {
    /* "'" are not accepted in parse_one_key. */
    gchar * input = g_strndup(pinyin, len);
    assert(NULL == strchr(input, '\''));

    guint16 tone = CHEWING_ZERO_TONE; guint16 tone_pos = 0;
    guint16 parsed_len = len;
    key = ChewingKey();

    if (options & USE_TONE) {
        /* find the tone in the last character. */
        char chr = input[parsed_len - 1];
        if ( '0' < chr && chr <= '5' ) {
            tone = chr - '0';
            parsed_len --;
            tone_pos = parsed_len;
        }
    }

    /* parse pinyin core staff here. */

    /* Note: optimize here? */
    input[parsed_len] = '\0';
    if (!search_pinyin_index(options, input, key)) {
        g_free(input);
        return false;
    }

    if (options & USE_TONE) {
        /* post processing tone. */
        if ( parsed_len == tone_pos ) {
            if (tone != CHEWING_ZERO_TONE) {
                key.m_tone = tone;
                parsed_len ++;
            }
        }
    }

    g_free(input);
    return parsed_len == len;
}


int FullPinyinParser2::parse (pinyin_option_t options, ChewingKeyVector & keys,
                              ChewingKeyRestVector & key_rests,
                              const char *str, int len) const {
    int i;
    /* clear arrays. */
    g_array_set_size(keys, 0);
    g_array_set_size(key_rests, 0);

    /* init m_parse_steps, and prepare dynamic programming. */
    int step_len = len + 1;
    g_array_set_size(m_parse_steps, 0);
    parse_value_t value;
    for (i = 0; i < step_len; ++i) {
        g_array_append_val(m_parse_steps, value);
    }

    size_t next_sep = 0;
    gchar * input = g_strndup(str, len);
    parse_value_t * curstep = NULL, * nextstep = NULL;

    for (i = 0; i < len; ++i) {
        if (input[i] == '\'') {
            curstep = &g_array_index(m_parse_steps, parse_value_t, i);
            nextstep = &g_array_index(m_parse_steps, parse_value_t, i + 1);

            /* propagate current step into next step. */
            nextstep->m_key = ChewingKey();
            nextstep->m_key_rest = ChewingKeyRest();
            nextstep->m_num_keys = curstep->m_num_keys;
            nextstep->m_parsed_len = curstep->m_parsed_len + 1;
            nextstep->m_last_step = i;
            next_sep = 0;
            continue;
        }

        /* forward to next "'" */
        if ( 0 == next_sep ) {
            int k;
            for (k = i;  k < len; ++k) {
                if (input[k] == '\'')
                    break;
            }
            next_sep = k;
        }

#if 0
        /* Heuristic Method:
         *   do maximum forward match first. */
        for (size_t pos = i; pos < next_sep; ++pos) {
            curstep = &g_array_index(m_parse_steps, parse_value_t, pos);
            size_t try_len = std_lite::min
                (pos + max_full_pinyin_length, next_sep);
            for (size_t n = try_len; n > pos; --n) {
                nextstep = &g_array_index(m_parse_steps, parse_value_t, n);

                /* gen next step */
                const char * onepinyin = input + pos;
                gint16 onepinyinlen = n - pos;
                value = parse_value_t();

                ChewingKey key; ChewingKeyRest rest;
                bool parsed = parse_one_key
                    (options, key, onepinyin, onepinyinlen);
                rest.m_raw_begin = pos; rest.m_raw_end = n;

                if (!parsed)
                    continue;

                //printf("onepinyin:%s len:%d\n", onepinyin, onepinyinlen);
                value.m_key = key; value.m_key_rest = rest;
                value.m_num_keys = curstep->m_num_keys + 1;
                value.m_parsed_len = curstep->m_parsed_len + onepinyinlen;
                value.m_last_step = pos;

                /* save next step */
                if (-1 == nextstep->m_last_step)
                    *nextstep = value;
                if (value.m_parsed_len > nextstep->m_parsed_len)
                    *nextstep = value;
                if (value.m_parsed_len == nextstep->m_parsed_len &&
                    value.m_num_keys < nextstep->m_num_keys)
                    *nextstep = value;

                /* maximum forward, set pos to n in next iteration. */
                pos = n - 1;
                break;
            }
        }
#endif

        /* dynamic programming here. */
        for (size_t m = i; m < next_sep; ++m) {
            curstep = &g_array_index(m_parse_steps, parse_value_t, m);
            size_t try_len = std_lite::min
                (m + max_full_pinyin_length, next_sep);
            for (size_t n = m + 1; n < try_len + 1; ++n) {
                nextstep = &g_array_index(m_parse_steps, parse_value_t, n);

                /* gen next step */
                const char * onepinyin = input + m;
                gint16 onepinyinlen = n - m;
                value = parse_value_t();

                ChewingKey key; ChewingKeyRest rest;
                bool parsed = parse_one_key
                    (options, key, onepinyin, onepinyinlen);
                rest.m_raw_begin = m; rest.m_raw_end = n;
                if (!parsed)
                    continue;

                //printf("onepinyin:%s len:%d\n", onepinyin, onepinyinlen);

                value.m_key = key; value.m_key_rest = rest;
                value.m_num_keys = curstep->m_num_keys + 1;
                value.m_parsed_len = curstep->m_parsed_len + onepinyinlen;
                value.m_last_step = m;

                /* save next step */
                if (-1 == nextstep->m_last_step)
                    *nextstep = value;
                if (value.m_parsed_len > nextstep->m_parsed_len)
                    *nextstep = value;
                if (value.m_parsed_len == nextstep->m_parsed_len &&
                    value.m_num_keys < nextstep->m_num_keys)
                    *nextstep = value;
                if (value.m_parsed_len == nextstep->m_parsed_len &&
                    value.m_num_keys == nextstep->m_num_keys &&
                    value.m_key.m_initial != CHEWING_ZERO_INITIAL &&
                    nextstep->m_key.m_initial == CHEWING_ZERO_INITIAL)
                    *nextstep = value;
            }
        }
    }

    /* final step for back tracing. */
    gint16 parsed_len = final_step(step_len, keys, key_rests);

    /* post processing for re-split table. */
    if (options & USE_RESPLIT_TABLE) {
        post_process(options, keys, key_rests);
    }

    g_free(input);
    return parsed_len;
}

int FullPinyinParser2::final_step(size_t step_len, ChewingKeyVector & keys,
                                  ChewingKeyRestVector & key_rests) const{
    int i;
    gint16 parsed_len = 0;
    parse_value_t * curstep = NULL;

    /* find longest match, which starts from the beginning of input. */
    for (i = step_len - 1; i >= 0; --i) {
        curstep = &g_array_index(m_parse_steps, parse_value_t, i);
        if (i == curstep->m_parsed_len)
            break;
    }
    /* prepare saving. */
    parsed_len = curstep->m_parsed_len;
    gint16 num_keys = curstep->m_num_keys;
    g_array_set_size(keys, num_keys);
    g_array_set_size(key_rests, num_keys);

    /* save the match. */
    while (curstep->m_last_step != -1) {
        gint16 pos = curstep->m_num_keys - 1;

        /* skip "'" */
        if (0 != curstep->m_key.get_table_index()) {
            ChewingKey * key = &g_array_index(keys, ChewingKey, pos);
            ChewingKeyRest * rest = &g_array_index
                (key_rests, ChewingKeyRest, pos);
            *key = curstep->m_key; *rest = curstep->m_key_rest;
        }

        /* back ward */
        curstep = &g_array_index(m_parse_steps, parse_value_t,
                                 curstep->m_last_step);
    }
    return parsed_len;
}


bool FullPinyinParser2::post_process(pinyin_option_t options,
                                     ChewingKeyVector & keys,
                                     ChewingKeyRestVector & key_rests) const {
    int i;
    assert(keys->len == key_rests->len);
    gint16 num_keys = keys->len;

    ChewingKey * cur_key = NULL, * next_key = NULL;
    ChewingKeyRest * cur_rest = NULL, * next_rest = NULL;
    guint16 next_tone = CHEWING_ZERO_TONE;

    for (i = 0; i < num_keys - 1; ++i) {
        cur_key = &g_array_index(keys, ChewingKey, i);
        next_key = &g_array_index(keys, ChewingKey, i + 1);

        /* some "'" here */
        if (0 == cur_key->get_table_index())
            continue;
        if (0 == next_key->get_table_index())
            continue;

        /* some tone here */
        if (CHEWING_ZERO_TONE != cur_key->m_tone)
            continue;

        cur_rest = &g_array_index(key_rests, ChewingKeyRest, i);
        next_rest = &g_array_index(key_rests, ChewingKeyRest, i + 1);

        if (options & USE_TONE) {
            next_tone = next_key->m_tone;
            next_key->m_tone = CHEWING_ZERO_TONE;
        }

        /* lookup re-split table */
        size_t k;
        const resplit_table_item_t * item = NULL;
        for (k = 0; k < G_N_ELEMENTS(resplit_table); ++k) {
            item = resplit_table + k;
            /* no ops */
            if (item->m_orig_freq >= item->m_new_freq)
                continue;

            /* use pinyin_exact_compare2 here. */
            if (0 == pinyin_exact_compare2(item->m_orig_keys,
                                           cur_key, 2))
                break;

        }

        /* find the match */
        if (k < G_N_ELEMENTS(resplit_table)) {
            /* do re-split */
            item = resplit_table + k;
            *cur_key = item->m_new_keys[0];
            *next_key = item->m_new_keys[1];
            /* assumes only moved one char in gen_all_resplit script. */
            cur_rest->m_raw_end ++;
            next_rest->m_raw_begin ++;
        }

        /* save back tones */
        if (options & USE_TONE) {
            next_key->m_tone = next_tone;
        }
    }

    return true;
}

#define IS_KEY(x)   (('a' <= x && x <= 'z') || x == ';')

bool DoublePinyinParser2::parse_one_key(pinyin_option_t options,
                                        ChewingKey & key,
                                        const char *str, int len) const {

    if (1 == len) {
        if (!(options & PINYIN_INCOMPLETE))
            return false;

        char ch = str[0];
        if (!IS_KEY(ch))
            return false;

        int charid = ch == ';' ? 26 : ch - 'a';
        const char * sheng = m_shengmu_table[charid].m_shengmu;
        if (NULL == sheng || strcmp(sheng, "'") == 0)
            return false;

        if (search_pinyin_index(options, sheng, key)) {
            return true;
        } else {
            return false;
        }
    }

    ChewingTone tone = CHEWING_ZERO_TONE;
    options &= ~(PINYIN_CORRECT_ALL|PINYIN_AMB_ALL);

    /* parse tone */
    if (3 == len) {
        if (!(options & USE_TONE))
            return false;
        char ch = str[2];
        if (!('0' < ch && ch <= '5'))
            return false;
        tone = (ChewingTone) (ch - '0');
    }

    if (2 == len || 3 == len) {
        /* parse shengmu here. */
        char ch = str[0];
        if (!IS_KEY(ch))
            return false;

        int charid = ch == ';' ? 26 : ch - 'a';
        const char * sheng = m_shengmu_table[charid].m_shengmu;
        if (NULL == sheng)
            return false;
        if (strcmp(sheng, "'") == 0)
            sheng = "";

        /* parse yunmu here. */
        ch = str[1];
        if (!IS_KEY(ch))
            return false;

        charid = ch == ';' ? 26 : ch - 'a';
        /* first yunmu */
        const char * yun = m_yunmu_table[charid].m_yunmus[0];
        gchar * pinyin = g_strdup_printf("%s%s", sheng, yun);
        if (search_pinyin_index(options, pinyin, key)) {
            key.m_tone = tone;
            g_free(pinyin);
            return true;
        }
        g_free(pinyin);

        /* second yunmu */
        yun = m_yunmu_table[charid].m_yunmus[1];
        pinyin = g_strdup_printf("%s%s", sheng, yun);
        if (search_pinyin_index(options, pinyin, key)) {
            key.m_tone = tone;
            g_free(pinyin);
            return true;
        }
        g_free(pinyin);

    }

    return false;
}


/* only 'a'-'z' and ';' are accepted here. */
int DoublePinyinParser2::parse(pinyin_option_t options, ChewingKeyVector & keys,
                               ChewingKeyRestVector & key_rests,
                               const char *str, int len) const {
    g_array_set_size(keys, 0);
    g_array_set_size(key_rests, 0);

    int maximum_len = 0; int i;
    /* probe the longest possible double pinyin string. */
    for (i = 0; i < len; ++i) {
        const char ch = str[i];
        if (!(IS_KEY(ch) || ('0' < ch && ch <= '5')))
            break;
    }
    maximum_len = i;

    /* maximum forward match for double pinyin. */
    int parsed_len = 0;
    while (parsed_len < maximum_len) {
        const char * cur_str = str + parsed_len;
        i = std_lite::min(maximum_len - parsed_len,
                          (int)max_double_pinyin_length);

        ChewingKey key; ChewingKeyRest key_rest;
        for (; i > 0; --i) {
            bool success = parse_one_key(options, key, cur_str, i);
            if (success)
                break;
        }

        if (0 == i)        /* no more possible double pinyins. */
            break;

        key_rest.m_raw_begin = parsed_len; key_rest.m_raw_end = parsed_len + i;
        parsed_len += i;

        /* save the pinyin */
        g_array_append_val(keys, key);
        g_array_append_val(key_rests, key_rest);
    }

    return parsed_len;
}

#undef IS_KEY

bool DoublePinyinParser2::set_scheme(DoublePinyinScheme scheme) {

    switch (scheme) {
    case DOUBLE_PINYIN_ZRM:
        m_shengmu_table = double_pinyin_zrm_sheng;
        m_yunmu_table   = double_pinyin_zrm_yun;
        return true;
    case DOUBLE_PINYIN_MS:
        m_shengmu_table = double_pinyin_mspy_sheng;
        m_yunmu_table   = double_pinyin_mspy_yun;
        return true;
    case DOUBLE_PINYIN_ZIGUANG:
        m_shengmu_table = double_pinyin_zgpy_sheng;
        m_yunmu_table   = double_pinyin_zgpy_yun;
        return true;
    case DOUBLE_PINYIN_ABC:
        m_shengmu_table = double_pinyin_abc_sheng;
        m_yunmu_table   = double_pinyin_abc_yun;
        return true;
    case DOUBLE_PINYIN_PYJJ:
        m_shengmu_table = double_pinyin_pyjj_sheng;
        m_yunmu_table   = double_pinyin_pyjj_yun;
        return true;
    case DOUBLE_PINYIN_XHE:
        m_shengmu_table = double_pinyin_xhe_sheng;
        m_yunmu_table   = double_pinyin_xhe_yun;
        return true;
    case DOUBLE_PINYIN_CUSTOMIZED:
        assert(FALSE);
    };

    return false; /* no such scheme. */
}

/* the chewing string must be freed with g_free. */
static bool search_chewing_symbols(const chewing_symbol_item_t * symbol_table,
                                   const char key, const char ** chewing) {
    *chewing = NULL;
    /* just iterate the table, as we only have < 50 items. */
    while (symbol_table->m_input != '\0') {
        if (symbol_table->m_input == key) {
            *chewing = symbol_table->m_chewing;
            return true;
        }
        symbol_table ++;
    }
    return false;
}

static bool search_chewing_tones(const chewing_tone_item_t * tone_table,
                                 const char key, char * tone) {
    *tone = CHEWING_ZERO_TONE;
    /* just iterate the table, as we only have < 10 items. */
    while (tone_table->m_input != '\0') {
        if (tone_table->m_input == key) {
            *tone = tone_table->m_tone;
            return true;
        }
        tone_table ++;
    }
    return false;
}


bool ChewingParser2::parse_one_key(pinyin_option_t options,
                                   ChewingKey & key,
                                   const char *str, int len) const {
    char tone = CHEWING_ZERO_TONE;

    int symbols_len = len;
    /* probe whether the last key is tone key in str. */
    if (options & USE_TONE) {
        char ch = str[len - 1];
        /* remove tone from input */
        if (search_chewing_tones(m_tone_table, ch, &tone))
            symbols_len --;
    }

    int i;
    gchar * chewing = NULL; const char * onechar = NULL;

    /* probe the possible chewing map in the rest of str. */
    for (i = 0; i < symbols_len; ++i) {
        if (!search_chewing_symbols(m_symbol_table, str[i], &onechar)) {
            g_free(chewing);
            return false;
        }

        if (!chewing) {
            chewing = g_strdup(onechar);
        } else {
            gchar * tmp = chewing;
            chewing = g_strconcat(chewing, onechar, NULL);
            g_free(tmp);
        }
    }

    /* search the chewing in the chewing index table. */
    if (chewing && search_chewing_index(options, chewing, key)) {
        /* save back tone if available. */
        key.m_tone = tone;
        g_free(chewing);
        return true;
    }

    g_free(chewing);
    return false;
}


/* only characters in chewing keyboard scheme are accepted here. */
int ChewingParser2::parse(pinyin_option_t options, ChewingKeyVector & keys,
                          ChewingKeyRestVector & key_rests,
                          const char *str, int len) const {
    g_array_set_size(keys, 0);
    g_array_set_size(key_rests, 0);

    int maximum_len = 0; int i;
    /* probe the longest possible chewing string. */
    for (i = 0; i < len; ++i) {
        if (!in_chewing_scheme(str[i], NULL))
            break;
    }
    maximum_len = i;

    /* maximum forward match for chewing. */
    int parsed_len = 0;
    while (parsed_len < maximum_len) {
        const char * cur_str = str + parsed_len;
        i = std_lite::min(maximum_len - parsed_len,
                          (int)max_chewing_length);

        ChewingKey key; ChewingKeyRest key_rest;
        for (; i > 0; --i) {
            bool success = parse_one_key(options, key, cur_str, i);
            if (success)
                break;
        }

        if (0 == i)        /* no more possible chewings. */
            break;

        key_rest.m_raw_begin = parsed_len; key_rest.m_raw_end = parsed_len + i;
        parsed_len += i;

        /* save the pinyin. */
        g_array_append_val(keys, key);
        g_array_append_val(key_rests, key_rest);
    }

    return parsed_len;
}


bool ChewingParser2::set_scheme(ChewingScheme scheme) {
    switch(scheme) {
    case CHEWING_STANDARD:
        m_symbol_table = chewing_standard_symbols;
        m_tone_table   = chewing_standard_tones;
        return true;
    case CHEWING_IBM:
        m_symbol_table = chewing_ibm_symbols;
        m_tone_table   = chewing_ibm_tones;
        return true;
    case CHEWING_GINYIEH:
        m_symbol_table = chewing_ginyieh_symbols;
        m_tone_table   = chewing_ginyieh_tones;
        return true;
    case CHEWING_ETEN:
        m_symbol_table = chewing_eten_symbols;
        m_tone_table   = chewing_eten_tones;
        return true;
    }

    return false;
}


bool ChewingParser2::in_chewing_scheme(const char key, const char ** symbol)
 const {
    const gchar * chewing = NULL;
    char tone = CHEWING_ZERO_TONE;

    if (search_chewing_symbols(m_symbol_table, key, &chewing)) {
        if (symbol)
            *symbol = chewing;
        return true;
    }

    if (search_chewing_tones(m_tone_table, key, &tone)) {
        if (symbol)
            *symbol = chewing_tone_table[tone];
        return true;
    }

    return false;
}