summaryrefslogtreecommitdiff
path: root/mysys/charset.c
blob: cc1d0a0111e8c25987c28dbd5dd23a2467a966fb (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
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
/*
   Copyright (c) 2000, 2011, Oracle and/or its affiliates

   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; version 2 of the License.

   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 St, Fifth Floor, Boston, MA 02110-1301  USA */

#include "mysys_priv.h"
#include "mysys_err.h"
#include <m_ctype.h>
#include <m_string.h>
#include <my_dir.h>
#include <my_xml.h>


/*
  The code below implements this functionality:
  
    - Initializing charset related structures
    - Loading dynamic charsets
    - Searching for a proper CHARSET_INFO 
      using charset name, collation name or collation ID
    - Setting server default character set
*/

my_bool my_charset_same(CHARSET_INFO *cs1, CHARSET_INFO *cs2)
{
  return ((cs1 == cs2) || !strcmp(cs1->csname,cs2->csname));
}


static uint
get_collation_number_internal(const char *name)
{
  CHARSET_INFO **cs;
  for (cs= all_charsets;
       cs < all_charsets + array_elements(all_charsets);
       cs++)
  {
    if ( cs[0] && cs[0]->name && 
         !my_strcasecmp(&my_charset_latin1, cs[0]->name, name))
      return cs[0]->number;
  }  
  return 0;
}


static my_bool init_state_maps(struct charset_info_st *cs)
{
  uint i;
  uchar *state_map;
  uchar *ident_map;

  if (!(cs->state_map= state_map= (uchar*) my_once_alloc(256, MYF(MY_WME))))
    return 1;
    
  if (!(cs->ident_map= ident_map= (uchar*) my_once_alloc(256, MYF(MY_WME))))
    return 1;

  /* Fill state_map with states to get a faster parser */
  for (i=0; i < 256 ; i++)
  {
    if (my_isalpha(cs,i))
      state_map[i]=(uchar) MY_LEX_IDENT;
    else if (my_isdigit(cs,i))
      state_map[i]=(uchar) MY_LEX_NUMBER_IDENT;
#if defined(USE_MB) && defined(USE_MB_IDENT)
    else if (my_mbcharlen(cs, i)>1)
      state_map[i]=(uchar) MY_LEX_IDENT;
#endif
    else if (my_isspace(cs,i))
      state_map[i]=(uchar) MY_LEX_SKIP;
    else
      state_map[i]=(uchar) MY_LEX_CHAR;
  }
  state_map[(uchar)'_']=state_map[(uchar)'$']=(uchar) MY_LEX_IDENT;
  state_map[(uchar)'\'']=(uchar) MY_LEX_STRING;
  state_map[(uchar)'.']=(uchar) MY_LEX_REAL_OR_POINT;
  state_map[(uchar)'>']=state_map[(uchar)'=']=state_map[(uchar)'!']= (uchar) MY_LEX_CMP_OP;
  state_map[(uchar)'<']= (uchar) MY_LEX_LONG_CMP_OP;
  state_map[(uchar)'&']=state_map[(uchar)'|']=(uchar) MY_LEX_BOOL;
  state_map[(uchar)'#']=(uchar) MY_LEX_COMMENT;
  state_map[(uchar)';']=(uchar) MY_LEX_SEMICOLON;
  state_map[(uchar)':']=(uchar) MY_LEX_SET_VAR;
  state_map[0]=(uchar) MY_LEX_EOL;
  state_map[(uchar)'\\']= (uchar) MY_LEX_ESCAPE;
  state_map[(uchar)'/']= (uchar) MY_LEX_LONG_COMMENT;
  state_map[(uchar)'*']= (uchar) MY_LEX_END_LONG_COMMENT;
  state_map[(uchar)'@']= (uchar) MY_LEX_USER_END;
  state_map[(uchar) '`']= (uchar) MY_LEX_USER_VARIABLE_DELIMITER;
  state_map[(uchar)'"']= (uchar) MY_LEX_STRING_OR_DELIMITER;
  state_map[(uchar)'-']= (uchar) MY_LEX_MINUS_OR_COMMENT;
  state_map[(uchar)',']= (uchar) MY_LEX_COMMA;
  state_map[(uchar)'?']= (uchar) MY_LEX_PLACEHOLDER;

  /*
    Create a second map to make it faster to find identifiers
  */
  for (i=0; i < 256 ; i++)
  {
    ident_map[i]= (uchar) (state_map[i] == MY_LEX_IDENT ||
			   state_map[i] == MY_LEX_NUMBER_IDENT);
  }

  /* Special handling of hex and binary strings */
  state_map[(uchar)'x']= state_map[(uchar)'X']= (uchar) MY_LEX_IDENT_OR_HEX;
  state_map[(uchar)'b']= state_map[(uchar)'B']= (uchar) MY_LEX_IDENT_OR_BIN;
  state_map[(uchar)'n']= state_map[(uchar)'N']= (uchar) MY_LEX_IDENT_OR_NCHAR;
  return 0;
}


static void simple_cs_init_functions(struct charset_info_st *cs)
{
  if (cs->state & MY_CS_BINSORT)
    cs->coll= &my_collation_8bit_bin_handler;
  else
    cs->coll= &my_collation_8bit_simple_ci_handler;
  
  cs->cset= &my_charset_8bit_handler;
}



static int cs_copy_data(struct charset_info_st *to, CHARSET_INFO *from)
{
  to->number= from->number ? from->number : to->number;

  if (from->csname)
    if (!(to->csname= my_once_strdup(from->csname,MYF(MY_WME))))
      goto err;
  
  if (from->name)
    if (!(to->name= my_once_strdup(from->name,MYF(MY_WME))))
      goto err;
  
  if (from->comment)
    if (!(to->comment= my_once_strdup(from->comment,MYF(MY_WME))))
      goto err;
  
  if (from->ctype)
  {
    if (!(to->ctype= (uchar*) my_once_memdup((char*) from->ctype,
					     MY_CS_CTYPE_TABLE_SIZE,
					     MYF(MY_WME))))
      goto err;
    if (init_state_maps(to))
      goto err;
  }
  if (from->to_lower)
    if (!(to->to_lower= (uchar*) my_once_memdup((char*) from->to_lower,
						MY_CS_TO_LOWER_TABLE_SIZE,
						MYF(MY_WME))))
      goto err;

  if (from->to_upper)
    if (!(to->to_upper= (uchar*) my_once_memdup((char*) from->to_upper,
						MY_CS_TO_UPPER_TABLE_SIZE,
						MYF(MY_WME))))
      goto err;
  if (from->sort_order)
  {
    if (!(to->sort_order= (uchar*) my_once_memdup((char*) from->sort_order,
						  MY_CS_SORT_ORDER_TABLE_SIZE,
						  MYF(MY_WME))))
      goto err;

  }
  if (from->tab_to_uni)
  {
    uint sz= MY_CS_TO_UNI_TABLE_SIZE*sizeof(uint16);
    if (!(to->tab_to_uni= (uint16*)  my_once_memdup((char*)from->tab_to_uni,
						    sz, MYF(MY_WME))))
      goto err;
  }
  if (from->tailoring)
    if (!(to->tailoring= my_once_strdup(from->tailoring,MYF(MY_WME))))
      goto err;

  return 0;

err:
  return 1;
}



static my_bool simple_cs_is_full(CHARSET_INFO *cs)
{
  return ((cs->csname && cs->tab_to_uni && cs->ctype && cs->to_upper &&
	   cs->to_lower) &&
	  (cs->number && cs->name &&
	  (cs->sort_order || (cs->state & MY_CS_BINSORT) )));
}


#if defined(HAVE_UCA_COLLATIONS) && (defined(HAVE_CHARSET_ucs2) || defined(HAVE_CHARSET_utf8))
static void
copy_uca_collation(struct charset_info_st *to, CHARSET_INFO *from)
{
  to->cset= from->cset;
  to->coll= from->coll;
  to->strxfrm_multiply= from->strxfrm_multiply;
  to->min_sort_char= from->min_sort_char;
  to->max_sort_char= from->max_sort_char;
  to->mbminlen= from->mbminlen;
  to->mbmaxlen= from->mbmaxlen;
  to->state|= MY_CS_AVAILABLE | MY_CS_LOADED |
              MY_CS_STRNXFRM  | MY_CS_UNICODE;
}
#endif


static int add_collation(struct charset_info_st *cs)
{
  if (cs->name && (cs->number ||
                   (cs->number=get_collation_number_internal(cs->name))) &&
      cs->number < array_elements(all_charsets))
  {
    struct charset_info_st *newcs;
    if (!(newcs= (struct charset_info_st*) all_charsets[cs->number]))
    {
      if (!(all_charsets[cs->number]= newcs=
         (struct charset_info_st*) my_once_alloc(sizeof(CHARSET_INFO),MYF(0))))
        return MY_XML_ERROR;
      bzero(newcs,sizeof(CHARSET_INFO));
    }
    
    if (cs->primary_number == cs->number)
      cs->state |= MY_CS_PRIMARY;
      
    if (cs->binary_number == cs->number)
      cs->state |= MY_CS_BINSORT;
    
    newcs->state|= cs->state;
    
    if (!(newcs->state & MY_CS_COMPILED))
    {
      if (cs_copy_data(newcs,cs))
        return MY_XML_ERROR;

      newcs->caseup_multiply= newcs->casedn_multiply= 1;

      if (!strcmp(cs->csname,"ucs2") )
      {
#if defined(HAVE_CHARSET_ucs2) && defined(HAVE_UCA_COLLATIONS)
        copy_uca_collation(newcs, &my_charset_ucs2_unicode_ci);
        newcs->state|= MY_CS_AVAILABLE | MY_CS_LOADED | MY_CS_NONASCII;
#endif        
      }
      else if (!strcmp(cs->csname, "utf8") || !strcmp(cs->csname, "utf8mb3"))
      {
#if defined (HAVE_CHARSET_utf8) && defined(HAVE_UCA_COLLATIONS)
        copy_uca_collation(newcs, &my_charset_utf8_unicode_ci);
        newcs->ctype= my_charset_utf8_unicode_ci.ctype;
        if (init_state_maps(newcs))
          return MY_XML_ERROR;
#endif
      }
      else if (!strcmp(cs->csname, "utf8mb4"))
      {
#if defined (HAVE_CHARSET_utf8mb4) && defined(HAVE_UCA_COLLATIONS)
        copy_uca_collation(newcs, &my_charset_utf8mb4_unicode_ci);
        newcs->ctype= my_charset_utf8mb4_unicode_ci.ctype;
        newcs->state|= MY_CS_AVAILABLE | MY_CS_LOADED;
#endif
      }
      else if (!strcmp(cs->csname, "utf16"))
      {
#if defined (HAVE_CHARSET_utf16) && defined(HAVE_UCA_COLLATIONS)
        copy_uca_collation(newcs, &my_charset_utf16_unicode_ci);
        newcs->state|= MY_CS_AVAILABLE | MY_CS_LOADED | MY_CS_NONASCII;
#endif
      }
      else if (!strcmp(cs->csname, "utf32"))
      {
#if defined (HAVE_CHARSET_utf32) && defined(HAVE_UCA_COLLATIONS)
        copy_uca_collation(newcs, &my_charset_utf32_unicode_ci);
        newcs->state|= MY_CS_AVAILABLE | MY_CS_LOADED | MY_CS_NONASCII;
#endif
      }
      else
      {
        const uchar *sort_order= newcs->sort_order;
        simple_cs_init_functions(newcs);
        newcs->mbminlen= 1;
        newcs->mbmaxlen= 1;
        if (simple_cs_is_full(newcs))
        {
          newcs->state |= MY_CS_LOADED;
        }
        newcs->state|= MY_CS_AVAILABLE;
        
        /*
          Check if case sensitive sort order: A < a < B.
          We need MY_CS_FLAG for regex library, and for
          case sensitivity flag for 5.0 client protocol,
          to support isCaseSensitive() method in JDBC driver 
        */
        if (sort_order && sort_order['A'] < sort_order['a'] &&
                          sort_order['a'] < sort_order['B'])
          newcs->state|= MY_CS_CSSORT; 

        if (my_charset_is_8bit_pure_ascii(newcs))
          newcs->state|= MY_CS_PUREASCII;
        if (!my_charset_is_ascii_compatible(cs))
	  newcs->state|= MY_CS_NONASCII;
      }
    }
    else
    {
      /*
        We need the below to make get_charset_name()
        and get_charset_number() working even if a
        character set has not been really incompiled.
        The above functions are used for example
        in error message compiler extra/comp_err.c.
        If a character set was compiled, this information
        will get lost and overwritten in add_compiled_collation().
      */
      newcs->number= cs->number;
      if (cs->comment)
	if (!(newcs->comment= my_once_strdup(cs->comment,MYF(MY_WME))))
	  return MY_XML_ERROR;
      if (cs->csname)
        if (!(newcs->csname= my_once_strdup(cs->csname,MYF(MY_WME))))
	  return MY_XML_ERROR;
      if (cs->name)
	if (!(newcs->name= my_once_strdup(cs->name,MYF(MY_WME))))
	  return MY_XML_ERROR;
    }
    cs->number= 0;
    cs->primary_number= 0;
    cs->binary_number= 0;
    cs->name= NULL;
    cs->state= 0;
    cs->sort_order= NULL;
    cs->state= 0;
  }
  return MY_XML_OK;
}


#define MY_MAX_ALLOWED_BUF 1024*1024
#define MY_CHARSET_INDEX "Index.xml"

const char *charsets_dir= NULL;


static my_bool my_read_charset_file(const char *filename, myf myflags)
{
  uchar *buf;
  int  fd;
  size_t len, tmp_len;
  MY_STAT stat_info;
  
  if (!my_stat(filename, &stat_info, MYF(myflags)) ||
       ((len= (uint)stat_info.st_size) > MY_MAX_ALLOWED_BUF) ||
       !(buf= (uchar*) my_malloc(len,myflags)))
    return TRUE;
  
  if ((fd= mysql_file_open(key_file_charset, filename, O_RDONLY, myflags)) < 0)
    goto error;
  tmp_len= mysql_file_read(fd, buf, len, myflags);
  mysql_file_close(fd, myflags);
  if (tmp_len != len)
    goto error;
  
  if (my_parse_charset_xml((char*) buf,len,add_collation))
  {
#ifdef NOT_YET
    printf("ERROR at line %d pos %d '%s'\n",
	   my_xml_error_lineno(&p)+1,
	   my_xml_error_pos(&p),
	   my_xml_error_string(&p));
#endif
  }
  
  my_free(buf);
  return FALSE;

error:
  my_free(buf);
  return TRUE;
}


char *get_charsets_dir(char *buf)
{
  const char *sharedir= SHAREDIR;
  char *res;
  DBUG_ENTER("get_charsets_dir");

  if (charsets_dir != NULL)
    strmake(buf, charsets_dir, FN_REFLEN-1);
  else
  {
    if (test_if_hard_path(sharedir) ||
	is_prefix(sharedir, DEFAULT_CHARSET_HOME))
      strxmov(buf, sharedir, "/", CHARSET_DIR, NullS);
    else
      strxmov(buf, DEFAULT_CHARSET_HOME, "/", sharedir, "/", CHARSET_DIR,
	      NullS);
  }
  res= convert_dirname(buf,buf,NullS);
  DBUG_PRINT("info",("charsets dir: '%s'", buf));
  DBUG_RETURN(res);
}

CHARSET_INFO *all_charsets[MY_ALL_CHARSETS_SIZE]={NULL};
CHARSET_INFO *default_charset_info = &my_charset_latin1;

void add_compiled_collation(struct charset_info_st *cs)
{
  DBUG_ASSERT(cs->number < array_elements(all_charsets));
  all_charsets[cs->number]= cs;
  cs->state|= MY_CS_AVAILABLE;
}

static void *cs_alloc(size_t size)
{
  return my_once_alloc(size, MYF(MY_WME));
}


static my_pthread_once_t charsets_initialized= MY_PTHREAD_ONCE_INIT;
static my_pthread_once_t charsets_template= MY_PTHREAD_ONCE_INIT;

static void init_available_charsets(void)
{
  char fname[FN_REFLEN + sizeof(MY_CHARSET_INDEX)];
  struct charset_info_st **cs;

  bzero((char*) &all_charsets,sizeof(all_charsets));
  init_compiled_charsets(MYF(0));

  /* Copy compiled charsets */
  for (cs= (struct charset_info_st**) all_charsets;
       cs < (struct charset_info_st**) all_charsets +
            array_elements(all_charsets)-1 ;
       cs++)
  {
    if (*cs)
    {
      if (cs[0]->ctype)
        if (init_state_maps(*cs))
          *cs= NULL;
    }
  }

  strmov(get_charsets_dir(fname), MY_CHARSET_INDEX);
  my_read_charset_file(fname, MYF(0));
}


void free_charsets(void)
{
  charsets_initialized= charsets_template;
}


static const char*
get_collation_name_alias(const char *name, char *buf, size_t bufsize)
{
  if (!strncasecmp(name, "utf8mb3_", 8))
  {
    my_snprintf(buf, bufsize, "utf8_%s", name + 8);
    return buf;
  }
  return NULL;
}


uint get_collation_number(const char *name)
{
  uint id;
  char alias[64];
  my_pthread_once(&charsets_initialized, init_available_charsets);
  if ((id= get_collation_number_internal(name)))
    return id;
  if ((name= get_collation_name_alias(name, alias, sizeof(alias))))
    return get_collation_number_internal(name);
  return 0;
}


static uint
get_charset_number_internal(const char *charset_name, uint cs_flags)
{
  CHARSET_INFO **cs;
  
  for (cs= all_charsets;
       cs < all_charsets + array_elements(all_charsets);
       cs++)
  {
    if ( cs[0] && cs[0]->csname && (cs[0]->state & cs_flags) &&
         !my_strcasecmp(&my_charset_latin1, cs[0]->csname, charset_name))
      return cs[0]->number;
  }  
  return 0;
}


static const char*
get_charset_name_alias(const char *name)
{
  if (!my_strcasecmp(&my_charset_latin1, name, "utf8mb3"))
    return "utf8";
  return NULL;
}


uint get_charset_number(const char *charset_name, uint cs_flags)
{
  uint id;
  my_pthread_once(&charsets_initialized, init_available_charsets);
  if ((id= get_charset_number_internal(charset_name, cs_flags)))
    return id;
  if ((charset_name= get_charset_name_alias(charset_name)))
    return get_charset_number_internal(charset_name, cs_flags);
  return 0;
}
                  

const char *get_charset_name(uint charset_number)
{
  my_pthread_once(&charsets_initialized, init_available_charsets);

  if (charset_number < array_elements(all_charsets))
  {
    CHARSET_INFO *cs= all_charsets[charset_number];

    if (cs && (cs->number == charset_number) && cs->name)
      return (char*) cs->name;
  }
  
  return "?";   /* this mimics find_type() */
}


static CHARSET_INFO *get_internal_charset(uint cs_number, myf flags)
{
  char  buf[FN_REFLEN];
  struct charset_info_st *cs;

  DBUG_ASSERT(cs_number < array_elements(all_charsets));

  if ((cs= (struct charset_info_st*) all_charsets[cs_number]))
  {
    if (cs->state & MY_CS_READY)  /* if CS is already initialized */
        return cs;

    /*
      To make things thread safe we are not allowing other threads to interfere
      while we may changing the cs_info_table
    */
    mysql_mutex_lock(&THR_LOCK_charset);

    if (!(cs->state & (MY_CS_COMPILED|MY_CS_LOADED))) /* if CS is not in memory */
    {
      strxmov(get_charsets_dir(buf), cs->csname, ".xml", NullS);
      my_read_charset_file(buf,flags);
    }

    if (cs->state & MY_CS_AVAILABLE)
    {
      if (!(cs->state & MY_CS_READY))
      {
        if ((cs->cset->init && cs->cset->init(cs, cs_alloc)) ||
            (cs->coll->init && cs->coll->init(cs, cs_alloc)))
          cs= NULL;
        else
          cs->state|= MY_CS_READY;
      }
    }
    else
      cs= NULL;

    mysql_mutex_unlock(&THR_LOCK_charset);
  }
  return cs;
}


CHARSET_INFO *get_charset(uint cs_number, myf flags)
{
  CHARSET_INFO *cs;
  if (cs_number == default_charset_info->number)
    return default_charset_info;

  my_pthread_once(&charsets_initialized, init_available_charsets);
 
  if (cs_number >= array_elements(all_charsets)) 
    return NULL;
  
  cs=get_internal_charset(cs_number, flags);

  if (!cs && (flags & MY_WME))
  {
    char index_file[FN_REFLEN + sizeof(MY_CHARSET_INDEX)], cs_string[23];
    strmov(get_charsets_dir(index_file),MY_CHARSET_INDEX);
    cs_string[0]='#';
    int10_to_str(cs_number, cs_string+1, 10);
    my_error(EE_UNKNOWN_CHARSET, MYF(ME_BELL), cs_string, index_file);
  }
  return cs;
}

CHARSET_INFO *get_charset_by_name(const char *cs_name, myf flags)
{
  uint cs_number;
  CHARSET_INFO *cs;
  my_pthread_once(&charsets_initialized, init_available_charsets);

  cs_number=get_collation_number(cs_name);
  cs= cs_number ? get_internal_charset(cs_number,flags) : NULL;

  if (!cs && (flags & MY_WME))
  {
    char index_file[FN_REFLEN + sizeof(MY_CHARSET_INDEX)];
    strmov(get_charsets_dir(index_file),MY_CHARSET_INDEX);
    my_error(EE_UNKNOWN_COLLATION, MYF(ME_BELL), cs_name, index_file);
  }

  return cs;
}


CHARSET_INFO *get_charset_by_csname(const char *cs_name,
				    uint cs_flags,
				    myf flags)
{
  uint cs_number;
  CHARSET_INFO *cs;
  DBUG_ENTER("get_charset_by_csname");
  DBUG_PRINT("enter",("name: '%s'", cs_name));

  my_pthread_once(&charsets_initialized, init_available_charsets);

  cs_number= get_charset_number(cs_name, cs_flags);
  cs= cs_number ? get_internal_charset(cs_number, flags) : NULL;

  if (!cs && (flags & MY_WME))
  {
    char index_file[FN_REFLEN + sizeof(MY_CHARSET_INDEX)];
    strmov(get_charsets_dir(index_file),MY_CHARSET_INDEX);
    my_error(EE_UNKNOWN_CHARSET, MYF(ME_BELL), cs_name, index_file);
  }

  DBUG_RETURN(cs);
}


/**
  Resolve character set by the character set name (utf8, latin1, ...).

  The function tries to resolve character set by the specified name. If
  there is character set with the given name, it is assigned to the "cs"
  parameter and FALSE is returned. If there is no such character set,
  "default_cs" is assigned to the "cs" and TRUE is returned.

  @param[in] cs_name    Character set name.
  @param[in] default_cs Default character set.
  @param[out] cs        Variable to store character set.

  @return FALSE if character set was resolved successfully; TRUE if there
  is no character set with given name.
*/

my_bool resolve_charset(const char *cs_name,
                        CHARSET_INFO *default_cs,
                        CHARSET_INFO **cs)
{
  *cs= get_charset_by_csname(cs_name, MY_CS_PRIMARY, MYF(0));

  if (*cs == NULL)
  {
    *cs= default_cs;
    return TRUE;
  }

  return FALSE;
}


/**
  Resolve collation by the collation name (utf8_general_ci, ...).

  The function tries to resolve collation by the specified name. If there
  is collation with the given name, it is assigned to the "cl" parameter
  and FALSE is returned. If there is no such collation, "default_cl" is
  assigned to the "cl" and TRUE is returned.

  @param[out] cl        Variable to store collation.
  @param[in] cl_name    Collation name.
  @param[in] default_cl Default collation.

  @return FALSE if collation was resolved successfully; TRUE if there is no
  collation with given name.
*/

my_bool resolve_collation(const char *cl_name,
                          CHARSET_INFO *default_cl,
                          CHARSET_INFO **cl)
{
  *cl= get_charset_by_name(cl_name, MYF(0));

  if (*cl == NULL)
  {
    *cl= default_cl;
    return TRUE;
  }

  return FALSE;
}


/*
  Escape string with backslashes (\)

  SYNOPSIS
    escape_string_for_mysql()
    charset_info        Charset of the strings
    to                  Buffer for escaped string
    to_length           Length of destination buffer, or 0
    from                The string to escape
    length              The length of the string to escape

  DESCRIPTION
    This escapes the contents of a string by adding backslashes before special
    characters, and turning others into specific escape sequences, such as
    turning newlines into \n and null bytes into \0.

  NOTE
    To maintain compatibility with the old C API, to_length may be 0 to mean
    "big enough"

  RETURN VALUES
    (size_t) -1 The escaped string did not fit in the to buffer
    #           The length of the escaped string
*/

size_t escape_string_for_mysql(CHARSET_INFO *charset_info,
                               char *to, size_t to_length,
                               const char *from, size_t length)
{
  const char *to_start= to;
  const char *end, *to_end=to_start + (to_length ? to_length-1 : 2*length);
  my_bool overflow= FALSE;
#ifdef USE_MB
  my_bool use_mb_flag= use_mb(charset_info);
#endif
  for (end= from + length; from < end; from++)
  {
    char escape= 0;
#ifdef USE_MB
    int tmp_length;
    if (use_mb_flag && (tmp_length= my_ismbchar(charset_info, from, end)))
    {
      if (to + tmp_length > to_end)
      {
        overflow= TRUE;
        break;
      }
      while (tmp_length--)
	*to++= *from++;
      from--;
      continue;
    }
    /*
     If the next character appears to begin a multi-byte character, we
     escape that first byte of that apparent multi-byte character. (The
     character just looks like a multi-byte character -- if it were actually
     a multi-byte character, it would have been passed through in the test
     above.)

     Without this check, we can create a problem by converting an invalid
     multi-byte character into a valid one. For example, 0xbf27 is not
     a valid GBK character, but 0xbf5c is. (0x27 = ', 0x5c = \)
    */
    if (use_mb_flag && (tmp_length= my_mbcharlen(charset_info, *from)) > 1)
      escape= *from;
    else
#endif
    switch (*from) {
    case 0:				/* Must be escaped for 'mysql' */
      escape= '0';
      break;
    case '\n':				/* Must be escaped for logs */
      escape= 'n';
      break;
    case '\r':
      escape= 'r';
      break;
    case '\\':
      escape= '\\';
      break;
    case '\'':
      escape= '\'';
      break;
    case '"':				/* Better safe than sorry */
      escape= '"';
      break;
    case '\032':			/* This gives problems on Win32 */
      escape= 'Z';
      break;
    }
    if (escape)
    {
      if (to + 2 > to_end)
      {
        overflow= TRUE;
        break;
      }
      *to++= '\\';
      *to++= escape;
    }
    else
    {
      if (to + 1 > to_end)
      {
        overflow= TRUE;
        break;
      }
      *to++= *from;
    }
  }
  *to= 0;
  return overflow ? (size_t) -1 : (size_t) (to - to_start);
}


#ifdef BACKSLASH_MBTAIL
static CHARSET_INFO *fs_cset_cache= NULL;

CHARSET_INFO *fs_character_set()
{
  if (!fs_cset_cache)
  {
    char buf[10]= "cp";
    GetLocaleInfo(LOCALE_SYSTEM_DEFAULT, LOCALE_IDEFAULTANSICODEPAGE,
                  buf+2, sizeof(buf)-3);
    /*
      We cannot call get_charset_by_name here
      because fs_character_set() is executed before
      LOCK_THD_charset mutex initialization, which
      is used inside get_charset_by_name.
      As we're now interested in cp932 only,
      let's just detect it using strcmp().
    */
    fs_cset_cache= !strcmp(buf, "cp932") ?
                   &my_charset_cp932_japanese_ci : &my_charset_bin;
  }
  return fs_cset_cache;
}
#endif

/*
  Escape apostrophes by doubling them up

  SYNOPSIS
    escape_quotes_for_mysql()
    charset_info        Charset of the strings
    to                  Buffer for escaped string
    to_length           Length of destination buffer, or 0
    from                The string to escape
    length              The length of the string to escape

  DESCRIPTION
    This escapes the contents of a string by doubling up any apostrophes that
    it contains. This is used when the NO_BACKSLASH_ESCAPES SQL_MODE is in
    effect on the server.

  NOTE
    To be consistent with escape_string_for_mysql(), to_length may be 0 to
    mean "big enough"

  RETURN VALUES
    ~0          The escaped string did not fit in the to buffer
    >=0         The length of the escaped string
*/

size_t escape_quotes_for_mysql(CHARSET_INFO *charset_info,
                               char *to, size_t to_length,
                               const char *from, size_t length)
{
  const char *to_start= to;
  const char *end, *to_end=to_start + (to_length ? to_length-1 : 2*length);
  my_bool overflow= FALSE;
#ifdef USE_MB
  my_bool use_mb_flag= use_mb(charset_info);
#endif
  for (end= from + length; from < end; from++)
  {
#ifdef USE_MB
    int tmp_length;
    if (use_mb_flag && (tmp_length= my_ismbchar(charset_info, from, end)))
    {
      if (to + tmp_length > to_end)
      {
        overflow= TRUE;
        break;
      }
      while (tmp_length--)
	*to++= *from++;
      from--;
      continue;
    }
    /*
      We don't have the same issue here with a non-multi-byte character being
      turned into a multi-byte character by the addition of an escaping
      character, because we are only escaping the ' character with itself.
     */
#endif
    if (*from == '\'')
    {
      if (to + 2 > to_end)
      {
        overflow= TRUE;
        break;
      }
      *to++= '\'';
      *to++= '\'';
    }
    else
    {
      if (to + 1 > to_end)
      {
        overflow= TRUE;
        break;
      }
      *to++= *from;
    }
  }
  *to= 0;
  return overflow ? (ulong)~0 : (ulong) (to - to_start);
}