summaryrefslogtreecommitdiff
path: root/gnu/quotearg.c
blob: 9f916592f6c25455f398cd5b293a6ab636d6bfb2 (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
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
/* quotearg.c - quote arguments for output

   Copyright (C) 1998-2002, 2004-2015 Free Software Foundation, Inc.

   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 3 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, see <http://www.gnu.org/licenses/>.  */

/* Written by Paul Eggert <eggert@twinsun.com> */

/* Without this pragma, gcc 4.7.0 20111124 mistakenly suggests that
   the quoting_options_from_style function might be candidate for
   attribute 'pure'  */
#if (__GNUC__ == 4 && 6 <= __GNUC_MINOR__) || 4 < __GNUC__
# pragma GCC diagnostic ignored "-Wsuggest-attribute=pure"
#endif

#include <config.h>

#include "quotearg.h"
#include "quote.h"

#include "xalloc.h"
#include "c-strcaseeq.h"
#include "localcharset.h"

#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#include <wctype.h>

#include "gettext.h"
#define _(msgid) gettext (msgid)
#define N_(msgid) msgid

#ifndef SIZE_MAX
# define SIZE_MAX ((size_t) -1)
#endif

#define INT_BITS (sizeof (int) * CHAR_BIT)

struct quoting_options
{
  /* Basic quoting style.  */
  enum quoting_style style;

  /* Additional flags.  Bitwise combination of enum quoting_flags.  */
  int flags;

  /* Quote the characters indicated by this bit vector even if the
     quoting style would not normally require them to be quoted.  */
  unsigned int quote_these_too[(UCHAR_MAX / INT_BITS) + 1];

  /* The left quote for custom_quoting_style.  */
  char const *left_quote;

  /* The right quote for custom_quoting_style.  */
  char const *right_quote;
};

/* Names of quoting styles.  */
char const *const quoting_style_args[] =
{
  "literal",
  "shell",
  "shell-always",
  "c",
  "c-maybe",
  "escape",
  "locale",
  "clocale",
  0
};

/* Correspondences to quoting style names.  */
enum quoting_style const quoting_style_vals[] =
{
  literal_quoting_style,
  shell_quoting_style,
  shell_always_quoting_style,
  c_quoting_style,
  c_maybe_quoting_style,
  escape_quoting_style,
  locale_quoting_style,
  clocale_quoting_style
};

/* The default quoting options.  */
static struct quoting_options default_quoting_options;

/* Allocate a new set of quoting options, with contents initially identical
   to O if O is not null, or to the default if O is null.
   It is the caller's responsibility to free the result.  */
struct quoting_options *
clone_quoting_options (struct quoting_options *o)
{
  int e = errno;
  struct quoting_options *p = xmemdup (o ? o : &default_quoting_options,
                                       sizeof *o);
  errno = e;
  return p;
}

/* Get the value of O's quoting style.  If O is null, use the default.  */
enum quoting_style
get_quoting_style (struct quoting_options *o)
{
  return (o ? o : &default_quoting_options)->style;
}

/* In O (or in the default if O is null),
   set the value of the quoting style to S.  */
void
set_quoting_style (struct quoting_options *o, enum quoting_style s)
{
  (o ? o : &default_quoting_options)->style = s;
}

/* In O (or in the default if O is null),
   set the value of the quoting options for character C to I.
   Return the old value.  Currently, the only values defined for I are
   0 (the default) and 1 (which means to quote the character even if
   it would not otherwise be quoted).  */
int
set_char_quoting (struct quoting_options *o, char c, int i)
{
  unsigned char uc = c;
  unsigned int *p =
    (o ? o : &default_quoting_options)->quote_these_too + uc / INT_BITS;
  int shift = uc % INT_BITS;
  int r = (*p >> shift) & 1;
  *p ^= ((i & 1) ^ r) << shift;
  return r;
}

/* In O (or in the default if O is null),
   set the value of the quoting options flag to I, which can be a
   bitwise combination of enum quoting_flags, or 0 for default
   behavior.  Return the old value.  */
int
set_quoting_flags (struct quoting_options *o, int i)
{
  int r;
  if (!o)
    o = &default_quoting_options;
  r = o->flags;
  o->flags = i;
  return r;
}

void
set_custom_quoting (struct quoting_options *o,
                    char const *left_quote, char const *right_quote)
{
  if (!o)
    o = &default_quoting_options;
  o->style = custom_quoting_style;
  if (!left_quote || !right_quote)
    abort ();
  o->left_quote = left_quote;
  o->right_quote = right_quote;
}

/* Return quoting options for STYLE, with no extra quoting.  */
static struct quoting_options /* NOT PURE!! */
quoting_options_from_style (enum quoting_style style)
{
  struct quoting_options o = { literal_quoting_style, 0, { 0 }, NULL, NULL };
  if (style == custom_quoting_style)
    abort ();
  o.style = style;
  return o;
}

/* MSGID approximates a quotation mark.  Return its translation if it
   has one; otherwise, return either it or "\"", depending on S.

   S is either clocale_quoting_style or locale_quoting_style.  */
static char const *
gettext_quote (char const *msgid, enum quoting_style s)
{
  char const *translation = _(msgid);
  char const *locale_code;

  if (translation != msgid)
    return translation;

  /* For UTF-8 and GB-18030, use single quotes U+2018 and U+2019.
     Here is a list of other locales that include U+2018 and U+2019:

        ISO-8859-7   0xA1                 KOI8-T       0x91
        CP869        0x8B                 CP874        0x91
        CP932        0x81 0x65            CP936        0xA1 0xAE
        CP949        0xA1 0xAE            CP950        0xA1 0xA5
        CP1250       0x91                 CP1251       0x91
        CP1252       0x91                 CP1253       0x91
        CP1254       0x91                 CP1255       0x91
        CP1256       0x91                 CP1257       0x91
        EUC-JP       0xA1 0xC6            EUC-KR       0xA1 0xAE
        EUC-TW       0xA1 0xE4            BIG5         0xA1 0xA5
        BIG5-HKSCS   0xA1 0xA5            EUC-CN       0xA1 0xAE
        GBK          0xA1 0xAE            Georgian-PS  0x91
        PT154        0x91

     None of these is still in wide use; using iconv is overkill.  */
  locale_code = locale_charset ();
  if (STRCASEEQ (locale_code, "UTF-8", 'U','T','F','-','8',0,0,0,0))
    return msgid[0] == '`' ? "\xe2\x80\x98": "\xe2\x80\x99";
  if (STRCASEEQ (locale_code, "GB18030", 'G','B','1','8','0','3','0',0,0))
    return msgid[0] == '`' ? "\xa1\ae": "\xa1\xaf";

  return (s == clocale_quoting_style ? "\"" : "'");
}

/* Place into buffer BUFFER (of size BUFFERSIZE) a quoted version of
   argument ARG (of size ARGSIZE), using QUOTING_STYLE, FLAGS, and
   QUOTE_THESE_TOO to control quoting.
   Terminate the output with a null character, and return the written
   size of the output, not counting the terminating null.
   If BUFFERSIZE is too small to store the output string, return the
   value that would have been returned had BUFFERSIZE been large enough.
   If ARGSIZE is SIZE_MAX, use the string length of the argument for ARGSIZE.

   This function acts like quotearg_buffer (BUFFER, BUFFERSIZE, ARG,
   ARGSIZE, O), except it breaks O into its component pieces and is
   not careful about errno.  */

static size_t
quotearg_buffer_restyled (char *buffer, size_t buffersize,
                          char const *arg, size_t argsize,
                          enum quoting_style quoting_style, int flags,
                          unsigned int const *quote_these_too,
                          char const *left_quote,
                          char const *right_quote)
{
  size_t i;
  size_t len = 0;
  char const *quote_string = 0;
  size_t quote_string_len = 0;
  bool backslash_escapes = false;
  bool unibyte_locale = MB_CUR_MAX == 1;
  bool elide_outer_quotes = (flags & QA_ELIDE_OUTER_QUOTES) != 0;

#define STORE(c) \
    do \
      { \
        if (len < buffersize) \
          buffer[len] = (c); \
        len++; \
      } \
    while (0)

  switch (quoting_style)
    {
    case c_maybe_quoting_style:
      quoting_style = c_quoting_style;
      elide_outer_quotes = true;
      /* Fall through.  */
    case c_quoting_style:
      if (!elide_outer_quotes)
        STORE ('"');
      backslash_escapes = true;
      quote_string = "\"";
      quote_string_len = 1;
      break;

    case escape_quoting_style:
      backslash_escapes = true;
      elide_outer_quotes = false;
      break;

    case locale_quoting_style:
    case clocale_quoting_style:
    case custom_quoting_style:
      {
        if (quoting_style != custom_quoting_style)
          {
            /* TRANSLATORS:
               Get translations for open and closing quotation marks.
               The message catalog should translate "`" to a left
               quotation mark suitable for the locale, and similarly for
               "'".  For example, a French Unicode local should translate
               these to U+00AB (LEFT-POINTING DOUBLE ANGLE
               QUOTATION MARK), and U+00BB (RIGHT-POINTING DOUBLE ANGLE
               QUOTATION MARK), respectively.

               If the catalog has no translation, we will try to
               use Unicode U+2018 (LEFT SINGLE QUOTATION MARK) and
               Unicode U+2019 (RIGHT SINGLE QUOTATION MARK).  If the
               current locale is not Unicode, locale_quoting_style
               will quote 'like this', and clocale_quoting_style will
               quote "like this".  You should always include translations
               for "`" and "'" even if U+2018 and U+2019 are appropriate
               for your locale.

               If you don't know what to put here, please see
               <http://en.wikipedia.org/wiki/Quotation_marks_in_other_languages>
               and use glyphs suitable for your language.  */
            left_quote = gettext_quote (N_("`"), quoting_style);
            right_quote = gettext_quote (N_("'"), quoting_style);
          }
        if (!elide_outer_quotes)
          for (quote_string = left_quote; *quote_string; quote_string++)
            STORE (*quote_string);
        backslash_escapes = true;
        quote_string = right_quote;
        quote_string_len = strlen (quote_string);
      }
      break;

    case shell_quoting_style:
      quoting_style = shell_always_quoting_style;
      elide_outer_quotes = true;
      /* Fall through.  */
    case shell_always_quoting_style:
      if (!elide_outer_quotes)
        STORE ('\'');
      quote_string = "'";
      quote_string_len = 1;
      break;

    case literal_quoting_style:
      elide_outer_quotes = false;
      break;

    default:
      abort ();
    }

  for (i = 0;  ! (argsize == SIZE_MAX ? arg[i] == '\0' : i == argsize);  i++)
    {
      unsigned char c;
      unsigned char esc;
      bool is_right_quote = false;

      if (backslash_escapes
          && quote_string_len
          && (i + quote_string_len
              <= (argsize == SIZE_MAX && 1 < quote_string_len
                  /* Use strlen only if we must: when argsize is SIZE_MAX,
                     and when the quote string is more than 1 byte long.
                     If we do call strlen, save the result.  */
                  ? (argsize = strlen (arg)) : argsize))
          && memcmp (arg + i, quote_string, quote_string_len) == 0)
        {
          if (elide_outer_quotes)
            goto force_outer_quoting_style;
          is_right_quote = true;
        }

      c = arg[i];
      switch (c)
        {
        case '\0':
          if (backslash_escapes)
            {
              if (elide_outer_quotes)
                goto force_outer_quoting_style;
              STORE ('\\');
              /* If quote_string were to begin with digits, we'd need to
                 test for the end of the arg as well.  However, it's
                 hard to imagine any locale that would use digits in
                 quotes, and set_custom_quoting is documented not to
                 accept them.  */
              if (i + 1 < argsize && '0' <= arg[i + 1] && arg[i + 1] <= '9')
                {
                  STORE ('0');
                  STORE ('0');
                }
              c = '0';
              /* We don't have to worry that this last '0' will be
                 backslash-escaped because, again, quote_string should
                 not start with it and because quote_these_too is
                 documented as not accepting it.  */
            }
          else if (flags & QA_ELIDE_NULL_BYTES)
            continue;
          break;

        case '?':
          switch (quoting_style)
            {
            case shell_always_quoting_style:
              if (elide_outer_quotes)
                goto force_outer_quoting_style;
              break;

            case c_quoting_style:
              if ((flags & QA_SPLIT_TRIGRAPHS)
                  && i + 2 < argsize && arg[i + 1] == '?')
                switch (arg[i + 2])
                  {
                  case '!': case '\'':
                  case '(': case ')': case '-': case '/':
                  case '<': case '=': case '>':
                    /* Escape the second '?' in what would otherwise be
                       a trigraph.  */
                    if (elide_outer_quotes)
                      goto force_outer_quoting_style;
                    c = arg[i + 2];
                    i += 2;
                    STORE ('?');
                    STORE ('"');
                    STORE ('"');
                    STORE ('?');
                    break;

                  default:
                    break;
                  }
              break;

            default:
              break;
            }
          break;

        case '\a': esc = 'a'; goto c_escape;
        case '\b': esc = 'b'; goto c_escape;
        case '\f': esc = 'f'; goto c_escape;
        case '\n': esc = 'n'; goto c_and_shell_escape;
        case '\r': esc = 'r'; goto c_and_shell_escape;
        case '\t': esc = 't'; goto c_and_shell_escape;
        case '\v': esc = 'v'; goto c_escape;
        case '\\': esc = c;
          /* No need to escape the escape if we are trying to elide
             outer quotes and nothing else is problematic.  */
          if (backslash_escapes && elide_outer_quotes && quote_string_len)
            goto store_c;

        c_and_shell_escape:
          if (quoting_style == shell_always_quoting_style
              && elide_outer_quotes)
            goto force_outer_quoting_style;
          /* Fall through.  */
        c_escape:
          if (backslash_escapes)
            {
              c = esc;
              goto store_escape;
            }
          break;

        case '{': case '}': /* sometimes special if isolated */
          if (! (argsize == SIZE_MAX ? arg[1] == '\0' : argsize == 1))
            break;
          /* Fall through.  */
        case '#': case '~':
          if (i != 0)
            break;
          /* Fall through.  */
        case ' ':
        case '!': /* special in bash */
        case '"': case '$': case '&':
        case '(': case ')': case '*': case ';':
        case '<':
        case '=': /* sometimes special in 0th or (with "set -k") later args */
        case '>': case '[':
        case '^': /* special in old /bin/sh, e.g. SunOS 4.1.4 */
        case '`': case '|':
          /* A shell special character.  In theory, '$' and '`' could
             be the first bytes of multibyte characters, which means
             we should check them with mbrtowc, but in practice this
             doesn't happen so it's not worth worrying about.  */
          if (quoting_style == shell_always_quoting_style
              && elide_outer_quotes)
            goto force_outer_quoting_style;
          break;

        case '\'':
          if (quoting_style == shell_always_quoting_style)
            {
              if (elide_outer_quotes)
                goto force_outer_quoting_style;
              STORE ('\'');
              STORE ('\\');
              STORE ('\'');
            }
          break;

        case '%': case '+': case ',': case '-': case '.': case '/':
        case '0': case '1': case '2': case '3': case '4': case '5':
        case '6': case '7': case '8': case '9': case ':':
        case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
        case 'G': case 'H': case 'I': case 'J': case 'K': case 'L':
        case 'M': case 'N': case 'O': case 'P': case 'Q': case 'R':
        case 'S': case 'T': case 'U': case 'V': case 'W': case 'X':
        case 'Y': case 'Z': case ']': case '_': case 'a': case 'b':
        case 'c': case 'd': case 'e': case 'f': case 'g': case 'h':
        case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
        case 'o': case 'p': case 'q': case 'r': case 's': case 't':
        case 'u': case 'v': case 'w': case 'x': case 'y': case 'z':
          /* These characters don't cause problems, no matter what the
             quoting style is.  They cannot start multibyte sequences.
             A digit or a special letter would cause trouble if it
             appeared at the beginning of quote_string because we'd then
             escape by prepending a backslash.  However, it's hard to
             imagine any locale that would use digits or letters as
             quotes, and set_custom_quoting is documented not to accept
             them.  Also, a digit or a special letter would cause
             trouble if it appeared in quote_these_too, but that's also
             documented as not accepting them.  */
          break;

        default:
          /* If we have a multibyte sequence, copy it until we reach
             its end, find an error, or come back to the initial shift
             state.  For C-like styles, if the sequence has
             unprintable characters, escape the whole sequence, since
             we can't easily escape single characters within it.  */
          {
            /* Length of multibyte sequence found so far.  */
            size_t m;

            bool printable;

            if (unibyte_locale)
              {
                m = 1;
                printable = isprint (c) != 0;
              }
            else
              {
                mbstate_t mbstate;
                memset (&mbstate, 0, sizeof mbstate);

                m = 0;
                printable = true;
                if (argsize == SIZE_MAX)
                  argsize = strlen (arg);

                do
                  {
                    wchar_t w;
                    size_t bytes = mbrtowc (&w, &arg[i + m],
                                            argsize - (i + m), &mbstate);
                    if (bytes == 0)
                      break;
                    else if (bytes == (size_t) -1)
                      {
                        printable = false;
                        break;
                      }
                    else if (bytes == (size_t) -2)
                      {
                        printable = false;
                        while (i + m < argsize && arg[i + m])
                          m++;
                        break;
                      }
                    else
                      {
                        /* Work around a bug with older shells that "see" a '\'
                           that is really the 2nd byte of a multibyte character.
                           In practice the problem is limited to ASCII
                           chars >= '@' that are shell special chars.  */
                        if ('[' == 0x5b && elide_outer_quotes
                            && quoting_style == shell_always_quoting_style)
                          {
                            size_t j;
                            for (j = 1; j < bytes; j++)
                              switch (arg[i + m + j])
                                {
                                case '[': case '\\': case '^':
                                case '`': case '|':
                                  goto force_outer_quoting_style;

                                default:
                                  break;
                                }
                          }

                        if (! iswprint (w))
                          printable = false;
                        m += bytes;
                      }
                  }
                while (! mbsinit (&mbstate));
              }

            if (1 < m || (backslash_escapes && ! printable))
              {
                /* Output a multibyte sequence, or an escaped
                   unprintable unibyte character.  */
                size_t ilim = i + m;

                for (;;)
                  {
                    if (backslash_escapes && ! printable)
                      {
                        if (elide_outer_quotes)
                          goto force_outer_quoting_style;
                        STORE ('\\');
                        STORE ('0' + (c >> 6));
                        STORE ('0' + ((c >> 3) & 7));
                        c = '0' + (c & 7);
                      }
                    else if (is_right_quote)
                      {
                        STORE ('\\');
                        is_right_quote = false;
                      }
                    if (ilim <= i + 1)
                      break;
                    STORE (c);
                    c = arg[++i];
                  }

                goto store_c;
              }
          }
        }

      if (! ((backslash_escapes || elide_outer_quotes)
             && quote_these_too
             && quote_these_too[c / INT_BITS] >> (c % INT_BITS) & 1)
          && !is_right_quote)
        goto store_c;

    store_escape:
      if (elide_outer_quotes)
        goto force_outer_quoting_style;
      STORE ('\\');

    store_c:
      STORE (c);
    }

  if (len == 0 && quoting_style == shell_always_quoting_style
      && elide_outer_quotes)
    goto force_outer_quoting_style;

  if (quote_string && !elide_outer_quotes)
    for (; *quote_string; quote_string++)
      STORE (*quote_string);

  if (len < buffersize)
    buffer[len] = '\0';
  return len;

 force_outer_quoting_style:
  /* Don't reuse quote_these_too, since the addition of outer quotes
     sufficiently quotes the specified characters.  */
  return quotearg_buffer_restyled (buffer, buffersize, arg, argsize,
                                   quoting_style,
                                   flags & ~QA_ELIDE_OUTER_QUOTES, NULL,
                                   left_quote, right_quote);
}

/* Place into buffer BUFFER (of size BUFFERSIZE) a quoted version of
   argument ARG (of size ARGSIZE), using O to control quoting.
   If O is null, use the default.
   Terminate the output with a null character, and return the written
   size of the output, not counting the terminating null.
   If BUFFERSIZE is too small to store the output string, return the
   value that would have been returned had BUFFERSIZE been large enough.
   If ARGSIZE is SIZE_MAX, use the string length of the argument for
   ARGSIZE.  */
size_t
quotearg_buffer (char *buffer, size_t buffersize,
                 char const *arg, size_t argsize,
                 struct quoting_options const *o)
{
  struct quoting_options const *p = o ? o : &default_quoting_options;
  int e = errno;
  size_t r = quotearg_buffer_restyled (buffer, buffersize, arg, argsize,
                                       p->style, p->flags, p->quote_these_too,
                                       p->left_quote, p->right_quote);
  errno = e;
  return r;
}

/* Equivalent to quotearg_alloc (ARG, ARGSIZE, NULL, O).  */
char *
quotearg_alloc (char const *arg, size_t argsize,
                struct quoting_options const *o)
{
  return quotearg_alloc_mem (arg, argsize, NULL, o);
}

/* Like quotearg_buffer (..., ARG, ARGSIZE, O), except return newly
   allocated storage containing the quoted string, and store the
   resulting size into *SIZE, if non-NULL.  The result can contain
   embedded null bytes only if ARGSIZE is not SIZE_MAX, SIZE is not
   NULL, and set_quoting_flags has not set the null byte elision
   flag.  */
char *
quotearg_alloc_mem (char const *arg, size_t argsize, size_t *size,
                    struct quoting_options const *o)
{
  struct quoting_options const *p = o ? o : &default_quoting_options;
  int e = errno;
  /* Elide embedded null bytes if we can't return a size.  */
  int flags = p->flags | (size ? 0 : QA_ELIDE_NULL_BYTES);
  size_t bufsize = quotearg_buffer_restyled (0, 0, arg, argsize, p->style,
                                             flags, p->quote_these_too,
                                             p->left_quote,
                                             p->right_quote) + 1;
  char *buf = xcharalloc (bufsize);
  quotearg_buffer_restyled (buf, bufsize, arg, argsize, p->style, flags,
                            p->quote_these_too,
                            p->left_quote, p->right_quote);
  errno = e;
  if (size)
    *size = bufsize - 1;
  return buf;
}

/* A storage slot with size and pointer to a value.  */
struct slotvec
{
  size_t size;
  char *val;
};

/* Preallocate a slot 0 buffer, so that the caller can always quote
   one small component of a "memory exhausted" message in slot 0.  */
static char slot0[256];
static unsigned int nslots = 1;
static struct slotvec slotvec0 = {sizeof slot0, slot0};
static struct slotvec *slotvec = &slotvec0;

void
quotearg_free (void)
{
  struct slotvec *sv = slotvec;
  unsigned int i;
  for (i = 1; i < nslots; i++)
    free (sv[i].val);
  if (sv[0].val != slot0)
    {
      free (sv[0].val);
      slotvec0.size = sizeof slot0;
      slotvec0.val = slot0;
    }
  if (sv != &slotvec0)
    {
      free (sv);
      slotvec = &slotvec0;
    }
  nslots = 1;
}

/* Use storage slot N to return a quoted version of argument ARG.
   ARG is of size ARGSIZE, but if that is SIZE_MAX, ARG is a
   null-terminated string.
   OPTIONS specifies the quoting options.
   The returned value points to static storage that can be
   reused by the next call to this function with the same value of N.
   N must be nonnegative.  N is deliberately declared with type "int"
   to allow for future extensions (using negative values).  */
static char *
quotearg_n_options (int n, char const *arg, size_t argsize,
                    struct quoting_options const *options)
{
  int e = errno;

  unsigned int n0 = n;
  struct slotvec *sv = slotvec;

  if (n < 0)
    abort ();

  if (nslots <= n0)
    {
      /* FIXME: technically, the type of n1 should be 'unsigned int',
         but that evokes an unsuppressible warning from gcc-4.0.1 and
         older.  If gcc ever provides an option to suppress that warning,
         revert to the original type, so that the test in xalloc_oversized
         is once again performed only at compile time.  */
      size_t n1 = n0 + 1;
      bool preallocated = (sv == &slotvec0);

      if (xalloc_oversized (n1, sizeof *sv))
        xalloc_die ();

      slotvec = sv = xrealloc (preallocated ? NULL : sv, n1 * sizeof *sv);
      if (preallocated)
        *sv = slotvec0;
      memset (sv + nslots, 0, (n1 - nslots) * sizeof *sv);
      nslots = n1;
    }

  {
    size_t size = sv[n].size;
    char *val = sv[n].val;
    /* Elide embedded null bytes since we don't return a size.  */
    int flags = options->flags | QA_ELIDE_NULL_BYTES;
    size_t qsize = quotearg_buffer_restyled (val, size, arg, argsize,
                                             options->style, flags,
                                             options->quote_these_too,
                                             options->left_quote,
                                             options->right_quote);

    if (size <= qsize)
      {
        sv[n].size = size = qsize + 1;
        if (val != slot0)
          free (val);
        sv[n].val = val = xcharalloc (size);
        quotearg_buffer_restyled (val, size, arg, argsize, options->style,
                                  flags, options->quote_these_too,
                                  options->left_quote,
                                  options->right_quote);
      }

    errno = e;
    return val;
  }
}

char *
quotearg_n (int n, char const *arg)
{
  return quotearg_n_options (n, arg, SIZE_MAX, &default_quoting_options);
}

char *
quotearg_n_mem (int n, char const *arg, size_t argsize)
{
  return quotearg_n_options (n, arg, argsize, &default_quoting_options);
}

char *
quotearg (char const *arg)
{
  return quotearg_n (0, arg);
}

char *
quotearg_mem (char const *arg, size_t argsize)
{
  return quotearg_n_mem (0, arg, argsize);
}

char *
quotearg_n_style (int n, enum quoting_style s, char const *arg)
{
  struct quoting_options const o = quoting_options_from_style (s);
  return quotearg_n_options (n, arg, SIZE_MAX, &o);
}

char *
quotearg_n_style_mem (int n, enum quoting_style s,
                      char const *arg, size_t argsize)
{
  struct quoting_options const o = quoting_options_from_style (s);
  return quotearg_n_options (n, arg, argsize, &o);
}

char *
quotearg_style (enum quoting_style s, char const *arg)
{
  return quotearg_n_style (0, s, arg);
}

char *
quotearg_style_mem (enum quoting_style s, char const *arg, size_t argsize)
{
  return quotearg_n_style_mem (0, s, arg, argsize);
}

char *
quotearg_char_mem (char const *arg, size_t argsize, char ch)
{
  struct quoting_options options;
  options = default_quoting_options;
  set_char_quoting (&options, ch, 1);
  return quotearg_n_options (0, arg, argsize, &options);
}

char *
quotearg_char (char const *arg, char ch)
{
  return quotearg_char_mem (arg, SIZE_MAX, ch);
}

char *
quotearg_colon (char const *arg)
{
  return quotearg_char (arg, ':');
}

char *
quotearg_colon_mem (char const *arg, size_t argsize)
{
  return quotearg_char_mem (arg, argsize, ':');
}

char *
quotearg_n_custom (int n, char const *left_quote,
                   char const *right_quote, char const *arg)
{
  return quotearg_n_custom_mem (n, left_quote, right_quote, arg,
                                SIZE_MAX);
}

char *
quotearg_n_custom_mem (int n, char const *left_quote,
                       char const *right_quote,
                       char const *arg, size_t argsize)
{
  struct quoting_options o = default_quoting_options;
  set_custom_quoting (&o, left_quote, right_quote);
  return quotearg_n_options (n, arg, argsize, &o);
}

char *
quotearg_custom (char const *left_quote, char const *right_quote,
                 char const *arg)
{
  return quotearg_n_custom (0, left_quote, right_quote, arg);
}

char *
quotearg_custom_mem (char const *left_quote, char const *right_quote,
                     char const *arg, size_t argsize)
{
  return quotearg_n_custom_mem (0, left_quote, right_quote, arg,
                                argsize);
}


/* The quoting option used by the functions of quote.h.  */
struct quoting_options quote_quoting_options =
  {
    locale_quoting_style,
    0,
    { 0 },
    NULL, NULL
  };

char const *
quote_n_mem (int n, char const *arg, size_t argsize)
{
  return quotearg_n_options (n, arg, argsize, &quote_quoting_options);
}

char const *
quote_mem (char const *arg, size_t argsize)
{
  return quote_n_mem (0, arg, argsize);
}

char const *
quote_n (int n, char const *arg)
{
  return quote_n_mem (n, arg, SIZE_MAX);
}

char const *
quote (char const *arg)
{
  return quote_n (0, arg);
}