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mbutils.c
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1 /*-------------------------------------------------------------------------
2  *
3  * mbutils.c
4  * This file contains functions for encoding conversion.
5  *
6  * The string-conversion functions in this file share some API quirks.
7  * Note the following:
8  *
9  * The functions return a palloc'd, null-terminated string if conversion
10  * is required. However, if no conversion is performed, the given source
11  * string pointer is returned as-is.
12  *
13  * Although the presence of a length argument means that callers can pass
14  * non-null-terminated strings, care is required because the same string
15  * will be passed back if no conversion occurs. Such callers *must* check
16  * whether result == src and handle that case differently.
17  *
18  * If the source and destination encodings are the same, the source string
19  * is returned without any verification; it's assumed to be valid data.
20  * If that might not be the case, the caller is responsible for validating
21  * the string using a separate call to pg_verify_mbstr(). Whenever the
22  * source and destination encodings are different, the functions ensure that
23  * the result is validly encoded according to the destination encoding.
24  *
25  *
26  * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
27  * Portions Copyright (c) 1994, Regents of the University of California
28  *
29  *
30  * IDENTIFICATION
31  * src/backend/utils/mb/mbutils.c
32  *
33  *-------------------------------------------------------------------------
34  */
35 #include "postgres.h"
36 
37 #include "access/xact.h"
38 #include "catalog/namespace.h"
39 #include "mb/pg_wchar.h"
40 #include "utils/builtins.h"
41 #include "utils/memutils.h"
42 #include "utils/syscache.h"
43 
44 /*
45  * We maintain a simple linked list caching the fmgr lookup info for the
46  * currently selected conversion functions, as well as any that have been
47  * selected previously in the current session. (We remember previous
48  * settings because we must be able to restore a previous setting during
49  * transaction rollback, without doing any fresh catalog accesses.)
50  *
51  * Since we'll never release this data, we just keep it in TopMemoryContext.
52  */
53 typedef struct ConvProcInfo
54 {
55  int s_encoding; /* server and client encoding IDs */
57  FmgrInfo to_server_info; /* lookup info for conversion procs */
59 } ConvProcInfo;
60 
61 static List *ConvProcList = NIL; /* List of ConvProcInfo */
62 
63 /*
64  * These variables point to the currently active conversion functions,
65  * or are NULL when no conversion is needed.
66  */
67 static FmgrInfo *ToServerConvProc = NULL;
68 static FmgrInfo *ToClientConvProc = NULL;
69 
70 /*
71  * This variable stores the conversion function to convert from UTF-8
72  * to the server encoding. It's NULL if the server encoding *is* UTF-8,
73  * or if we lack a conversion function for this.
74  */
76 
77 /*
78  * These variables track the currently-selected encodings.
79  */
83 
84 /*
85  * During backend startup we can't set client encoding because we (a)
86  * can't look up the conversion functions, and (b) may not know the database
87  * encoding yet either. So SetClientEncoding() just accepts anything and
88  * remembers it for InitializeClientEncoding() to apply later.
89  */
90 static bool backend_startup_complete = false;
92 
93 
94 /* Internal functions */
95 static char *perform_default_encoding_conversion(const char *src,
96  int len, bool is_client_to_server);
97 static int cliplen(const char *str, int len, int limit);
98 
99 
100 /*
101  * Prepare for a future call to SetClientEncoding. Success should mean
102  * that SetClientEncoding is guaranteed to succeed for this encoding request.
103  *
104  * (But note that success before backend_startup_complete does not guarantee
105  * success after ...)
106  *
107  * Returns 0 if okay, -1 if not (bad encoding or can't support conversion)
108  */
109 int
111 {
112  int current_server_encoding;
113  ListCell *lc;
114 
115  if (!PG_VALID_FE_ENCODING(encoding))
116  return -1;
117 
118  /* Can't do anything during startup, per notes above */
120  return 0;
121 
122  current_server_encoding = GetDatabaseEncoding();
123 
124  /*
125  * Check for cases that require no conversion function.
126  */
127  if (current_server_encoding == encoding ||
128  current_server_encoding == PG_SQL_ASCII ||
129  encoding == PG_SQL_ASCII)
130  return 0;
131 
132  if (IsTransactionState())
133  {
134  /*
135  * If we're in a live transaction, it's safe to access the catalogs,
136  * so look up the functions. We repeat the lookup even if the info is
137  * already cached, so that we can react to changes in the contents of
138  * pg_conversion.
139  */
140  Oid to_server_proc,
141  to_client_proc;
142  ConvProcInfo *convinfo;
143  MemoryContext oldcontext;
144 
145  to_server_proc = FindDefaultConversionProc(encoding,
146  current_server_encoding);
147  if (!OidIsValid(to_server_proc))
148  return -1;
149  to_client_proc = FindDefaultConversionProc(current_server_encoding,
150  encoding);
151  if (!OidIsValid(to_client_proc))
152  return -1;
153 
154  /*
155  * Load the fmgr info into TopMemoryContext (could still fail here)
156  */
158  sizeof(ConvProcInfo));
159  convinfo->s_encoding = current_server_encoding;
160  convinfo->c_encoding = encoding;
161  fmgr_info_cxt(to_server_proc, &convinfo->to_server_info,
163  fmgr_info_cxt(to_client_proc, &convinfo->to_client_info,
165 
166  /* Attach new info to head of list */
168  ConvProcList = lcons(convinfo, ConvProcList);
169  MemoryContextSwitchTo(oldcontext);
170 
171  /*
172  * We cannot yet remove any older entry for the same encoding pair,
173  * since it could still be in use. SetClientEncoding will clean up.
174  */
175 
176  return 0; /* success */
177  }
178  else
179  {
180  /*
181  * If we're not in a live transaction, the only thing we can do is
182  * restore a previous setting using the cache. This covers all
183  * transaction-rollback cases. The only case it might not work for is
184  * trying to change client_encoding on the fly by editing
185  * postgresql.conf and SIGHUP'ing. Which would probably be a stupid
186  * thing to do anyway.
187  */
188  foreach(lc, ConvProcList)
189  {
190  ConvProcInfo *oldinfo = (ConvProcInfo *) lfirst(lc);
191 
192  if (oldinfo->s_encoding == current_server_encoding &&
193  oldinfo->c_encoding == encoding)
194  return 0;
195  }
196 
197  return -1; /* it's not cached, so fail */
198  }
199 }
200 
201 /*
202  * Set the active client encoding and set up the conversion-function pointers.
203  * PrepareClientEncoding should have been called previously for this encoding.
204  *
205  * Returns 0 if okay, -1 if not (bad encoding or can't support conversion)
206  */
207 int
209 {
210  int current_server_encoding;
211  bool found;
212  ListCell *lc;
213 
214  if (!PG_VALID_FE_ENCODING(encoding))
215  return -1;
216 
217  /* Can't do anything during startup, per notes above */
219  {
221  return 0;
222  }
223 
224  current_server_encoding = GetDatabaseEncoding();
225 
226  /*
227  * Check for cases that require no conversion function.
228  */
229  if (current_server_encoding == encoding ||
230  current_server_encoding == PG_SQL_ASCII ||
231  encoding == PG_SQL_ASCII)
232  {
233  ClientEncoding = &pg_enc2name_tbl[encoding];
234  ToServerConvProc = NULL;
235  ToClientConvProc = NULL;
236  return 0;
237  }
238 
239  /*
240  * Search the cache for the entry previously prepared by
241  * PrepareClientEncoding; if there isn't one, we lose. While at it,
242  * release any duplicate entries so that repeated Prepare/Set cycles don't
243  * leak memory.
244  */
245  found = false;
246  foreach(lc, ConvProcList)
247  {
248  ConvProcInfo *convinfo = (ConvProcInfo *) lfirst(lc);
249 
250  if (convinfo->s_encoding == current_server_encoding &&
251  convinfo->c_encoding == encoding)
252  {
253  if (!found)
254  {
255  /* Found newest entry, so set up */
256  ClientEncoding = &pg_enc2name_tbl[encoding];
257  ToServerConvProc = &convinfo->to_server_info;
258  ToClientConvProc = &convinfo->to_client_info;
259  found = true;
260  }
261  else
262  {
263  /* Duplicate entry, release it */
264  ConvProcList = foreach_delete_current(ConvProcList, lc);
265  pfree(convinfo);
266  }
267  }
268  }
269 
270  if (found)
271  return 0; /* success */
272  else
273  return -1; /* it's not cached, so fail */
274 }
275 
276 /*
277  * Initialize client encoding conversions.
278  * Called from InitPostgres() once during backend startup.
279  */
280 void
282 {
283  int current_server_encoding;
284 
287 
290  {
291  /*
292  * Oops, the requested conversion is not available. We couldn't fail
293  * before, but we can now.
294  */
295  ereport(FATAL,
296  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
297  errmsg("conversion between %s and %s is not supported",
300  }
301 
302  /*
303  * Also look up the UTF8-to-server conversion function if needed. Since
304  * the server encoding is fixed within any one backend process, we don't
305  * have to do this more than once.
306  */
307  current_server_encoding = GetDatabaseEncoding();
308  if (current_server_encoding != PG_UTF8 &&
309  current_server_encoding != PG_SQL_ASCII)
310  {
311  Oid utf8_to_server_proc;
312 
314  utf8_to_server_proc =
316  current_server_encoding);
317  /* If there's no such conversion, just leave the pointer as NULL */
318  if (OidIsValid(utf8_to_server_proc))
319  {
320  FmgrInfo *finfo;
321 
323  sizeof(FmgrInfo));
324  fmgr_info_cxt(utf8_to_server_proc, finfo,
326  /* Set Utf8ToServerConvProc only after data is fully valid */
327  Utf8ToServerConvProc = finfo;
328  }
329  }
330 }
331 
332 /*
333  * returns the current client encoding
334  */
335 int
337 {
338  return ClientEncoding->encoding;
339 }
340 
341 /*
342  * returns the current client encoding name
343  */
344 const char *
346 {
347  return ClientEncoding->name;
348 }
349 
350 /*
351  * Convert src string to another encoding (general case).
352  *
353  * See the notes about string conversion functions at the top of this file.
354  */
355 unsigned char *
356 pg_do_encoding_conversion(unsigned char *src, int len,
357  int src_encoding, int dest_encoding)
358 {
359  unsigned char *result;
360  Oid proc;
361 
362  if (len <= 0)
363  return src; /* empty string is always valid */
364 
365  if (src_encoding == dest_encoding)
366  return src; /* no conversion required, assume valid */
367 
368  if (dest_encoding == PG_SQL_ASCII)
369  return src; /* any string is valid in SQL_ASCII */
370 
371  if (src_encoding == PG_SQL_ASCII)
372  {
373  /* No conversion is possible, but we must validate the result */
374  (void) pg_verify_mbstr(dest_encoding, (const char *) src, len, false);
375  return src;
376  }
377 
378  if (!IsTransactionState()) /* shouldn't happen */
379  elog(ERROR, "cannot perform encoding conversion outside a transaction");
380 
381  proc = FindDefaultConversionProc(src_encoding, dest_encoding);
382  if (!OidIsValid(proc))
383  ereport(ERROR,
384  (errcode(ERRCODE_UNDEFINED_FUNCTION),
385  errmsg("default conversion function for encoding \"%s\" to \"%s\" does not exist",
386  pg_encoding_to_char(src_encoding),
387  pg_encoding_to_char(dest_encoding))));
388 
389  /*
390  * Allocate space for conversion result, being wary of integer overflow.
391  *
392  * len * MAX_CONVERSION_GROWTH is typically a vast overestimate of the
393  * required space, so it might exceed MaxAllocSize even though the result
394  * would actually fit. We do not want to hand back a result string that
395  * exceeds MaxAllocSize, because callers might not cope gracefully --- but
396  * if we just allocate more than that, and don't use it, that's fine.
397  */
398  if ((Size) len >= (MaxAllocHugeSize / (Size) MAX_CONVERSION_GROWTH))
399  ereport(ERROR,
400  (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
401  errmsg("out of memory"),
402  errdetail("String of %d bytes is too long for encoding conversion.",
403  len)));
404 
405  result = (unsigned char *)
407  (Size) len * MAX_CONVERSION_GROWTH + 1);
408 
409  (void) OidFunctionCall6(proc,
410  Int32GetDatum(src_encoding),
411  Int32GetDatum(dest_encoding),
412  CStringGetDatum(src),
413  CStringGetDatum(result),
414  Int32GetDatum(len),
415  BoolGetDatum(false));
416 
417  /*
418  * If the result is large, it's worth repalloc'ing to release any extra
419  * space we asked for. The cutoff here is somewhat arbitrary, but we
420  * *must* check when len * MAX_CONVERSION_GROWTH exceeds MaxAllocSize.
421  */
422  if (len > 1000000)
423  {
424  Size resultlen = strlen((char *) result);
425 
426  if (resultlen >= MaxAllocSize)
427  ereport(ERROR,
428  (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
429  errmsg("out of memory"),
430  errdetail("String of %d bytes is too long for encoding conversion.",
431  len)));
432 
433  result = (unsigned char *) repalloc(result, resultlen + 1);
434  }
435 
436  return result;
437 }
438 
439 /*
440  * Convert src string to another encoding.
441  *
442  * This function has a different API than the other conversion functions.
443  * The caller should've looked up the conversion function using
444  * FindDefaultConversionProc(). Unlike the other functions, the converted
445  * result is not palloc'd. It is written to the caller-supplied buffer
446  * instead.
447  *
448  * src_encoding - encoding to convert from
449  * dest_encoding - encoding to convert to
450  * src, srclen - input buffer and its length in bytes
451  * dest, destlen - destination buffer and its size in bytes
452  *
453  * The output is null-terminated.
454  *
455  * If destlen < srclen * MAX_CONVERSION_LENGTH + 1, the converted output
456  * wouldn't necessarily fit in the output buffer, and the function will not
457  * convert the whole input.
458  *
459  * TODO: The conversion function interface is not great. Firstly, it
460  * would be nice to pass through the destination buffer size to the
461  * conversion function, so that if you pass a shorter destination buffer, it
462  * could still continue to fill up the whole buffer. Currently, we have to
463  * assume worst case expansion and stop the conversion short, even if there
464  * is in fact space left in the destination buffer. Secondly, it would be
465  * nice to return the number of bytes written to the caller, to avoid a call
466  * to strlen().
467  */
468 int
470  int src_encoding,
471  int dest_encoding,
472  unsigned char *src, int srclen,
473  unsigned char *dest, int destlen,
474  bool noError)
475 {
476  Datum result;
477 
478  /*
479  * If the destination buffer is not large enough to hold the result in the
480  * worst case, limit the input size passed to the conversion function.
481  */
482  if ((Size) srclen >= ((destlen - 1) / (Size) MAX_CONVERSION_GROWTH))
483  srclen = ((destlen - 1) / (Size) MAX_CONVERSION_GROWTH);
484 
485  result = OidFunctionCall6(proc,
486  Int32GetDatum(src_encoding),
487  Int32GetDatum(dest_encoding),
488  CStringGetDatum(src),
489  CStringGetDatum(dest),
490  Int32GetDatum(srclen),
491  BoolGetDatum(noError));
492  return DatumGetInt32(result);
493 }
494 
495 /*
496  * Convert string to encoding encoding_name. The source
497  * encoding is the DB encoding.
498  *
499  * BYTEA convert_to(TEXT string, NAME encoding_name) */
500 Datum
502 {
503  Datum string = PG_GETARG_DATUM(0);
504  Datum dest_encoding_name = PG_GETARG_DATUM(1);
505  Datum src_encoding_name = DirectFunctionCall1(namein,
506  CStringGetDatum(DatabaseEncoding->name));
507  Datum result;
508 
509  /*
510  * pg_convert expects a bytea as its first argument. We're passing it a
511  * text argument here, relying on the fact that they are both in fact
512  * varlena types, and thus structurally identical.
513  */
514  result = DirectFunctionCall3(pg_convert, string,
515  src_encoding_name, dest_encoding_name);
516 
517  PG_RETURN_DATUM(result);
518 }
519 
520 /*
521  * Convert string from encoding encoding_name. The destination
522  * encoding is the DB encoding.
523  *
524  * TEXT convert_from(BYTEA string, NAME encoding_name) */
525 Datum
527 {
528  Datum string = PG_GETARG_DATUM(0);
529  Datum src_encoding_name = PG_GETARG_DATUM(1);
530  Datum dest_encoding_name = DirectFunctionCall1(namein,
531  CStringGetDatum(DatabaseEncoding->name));
532  Datum result;
533 
534  result = DirectFunctionCall3(pg_convert, string,
535  src_encoding_name, dest_encoding_name);
536 
537  /*
538  * pg_convert returns a bytea, which we in turn return as text, relying on
539  * the fact that they are both in fact varlena types, and thus
540  * structurally identical. Although not all bytea values are valid text,
541  * in this case it will be because we've told pg_convert to return one
542  * that is valid as text in the current database encoding.
543  */
544  PG_RETURN_DATUM(result);
545 }
546 
547 /*
548  * Convert string between two arbitrary encodings.
549  *
550  * BYTEA convert(BYTEA string, NAME src_encoding_name, NAME dest_encoding_name)
551  */
552 Datum
554 {
555  bytea *string = PG_GETARG_BYTEA_PP(0);
556  char *src_encoding_name = NameStr(*PG_GETARG_NAME(1));
557  int src_encoding = pg_char_to_encoding(src_encoding_name);
558  char *dest_encoding_name = NameStr(*PG_GETARG_NAME(2));
559  int dest_encoding = pg_char_to_encoding(dest_encoding_name);
560  const char *src_str;
561  char *dest_str;
562  bytea *retval;
563  int len;
564 
565  if (src_encoding < 0)
566  ereport(ERROR,
567  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
568  errmsg("invalid source encoding name \"%s\"",
569  src_encoding_name)));
570  if (dest_encoding < 0)
571  ereport(ERROR,
572  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
573  errmsg("invalid destination encoding name \"%s\"",
574  dest_encoding_name)));
575 
576  /* make sure that source string is valid */
577  len = VARSIZE_ANY_EXHDR(string);
578  src_str = VARDATA_ANY(string);
579  (void) pg_verify_mbstr(src_encoding, src_str, len, false);
580 
581  /* perform conversion */
582  dest_str = (char *) pg_do_encoding_conversion((unsigned char *) unconstify(char *, src_str),
583  len,
584  src_encoding,
585  dest_encoding);
586 
587  /* update len if conversion actually happened */
588  if (dest_str != src_str)
589  len = strlen(dest_str);
590 
591  /*
592  * build bytea data type structure.
593  */
594  retval = (bytea *) palloc(len + VARHDRSZ);
595  SET_VARSIZE(retval, len + VARHDRSZ);
596  memcpy(VARDATA(retval), dest_str, len);
597 
598  if (dest_str != src_str)
599  pfree(dest_str);
600 
601  /* free memory if allocated by the toaster */
602  PG_FREE_IF_COPY(string, 0);
603 
604  PG_RETURN_BYTEA_P(retval);
605 }
606 
607 /*
608  * get the length of the string considered as text in the specified
609  * encoding. Raises an error if the data is not valid in that
610  * encoding.
611  *
612  * INT4 length (BYTEA string, NAME src_encoding_name)
613  */
614 Datum
616 {
617  bytea *string = PG_GETARG_BYTEA_PP(0);
618  char *src_encoding_name = NameStr(*PG_GETARG_NAME(1));
619  int src_encoding = pg_char_to_encoding(src_encoding_name);
620  const char *src_str;
621  int len;
622  int retval;
623 
624  if (src_encoding < 0)
625  ereport(ERROR,
626  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
627  errmsg("invalid encoding name \"%s\"",
628  src_encoding_name)));
629 
630  len = VARSIZE_ANY_EXHDR(string);
631  src_str = VARDATA_ANY(string);
632 
633  retval = pg_verify_mbstr_len(src_encoding, src_str, len, false);
634 
635  PG_RETURN_INT32(retval);
636 }
637 
638 /*
639  * Get maximum multibyte character length in the specified encoding.
640  *
641  * Note encoding is specified numerically, not by name as above.
642  */
643 Datum
645 {
646  int encoding = PG_GETARG_INT32(0);
647 
648  if (PG_VALID_ENCODING(encoding))
649  PG_RETURN_INT32(pg_wchar_table[encoding].maxmblen);
650  else
651  PG_RETURN_NULL();
652 }
653 
654 /*
655  * Convert client encoding to server encoding.
656  *
657  * See the notes about string conversion functions at the top of this file.
658  */
659 char *
660 pg_client_to_server(const char *s, int len)
661 {
662  return pg_any_to_server(s, len, ClientEncoding->encoding);
663 }
664 
665 /*
666  * Convert any encoding to server encoding.
667  *
668  * See the notes about string conversion functions at the top of this file.
669  *
670  * Unlike the other string conversion functions, this will apply validation
671  * even if encoding == DatabaseEncoding->encoding. This is because this is
672  * used to process data coming in from outside the database, and we never
673  * want to just assume validity.
674  */
675 char *
676 pg_any_to_server(const char *s, int len, int encoding)
677 {
678  if (len <= 0)
679  return unconstify(char *, s); /* empty string is always valid */
680 
681  if (encoding == DatabaseEncoding->encoding ||
682  encoding == PG_SQL_ASCII)
683  {
684  /*
685  * No conversion is needed, but we must still validate the data.
686  */
687  (void) pg_verify_mbstr(DatabaseEncoding->encoding, s, len, false);
688  return unconstify(char *, s);
689  }
690 
691  if (DatabaseEncoding->encoding == PG_SQL_ASCII)
692  {
693  /*
694  * No conversion is possible, but we must still validate the data,
695  * because the client-side code might have done string escaping using
696  * the selected client_encoding. If the client encoding is ASCII-safe
697  * then we just do a straight validation under that encoding. For an
698  * ASCII-unsafe encoding we have a problem: we dare not pass such data
699  * to the parser but we have no way to convert it. We compromise by
700  * rejecting the data if it contains any non-ASCII characters.
701  */
702  if (PG_VALID_BE_ENCODING(encoding))
703  (void) pg_verify_mbstr(encoding, s, len, false);
704  else
705  {
706  int i;
707 
708  for (i = 0; i < len; i++)
709  {
710  if (s[i] == '\0' || IS_HIGHBIT_SET(s[i]))
711  ereport(ERROR,
712  (errcode(ERRCODE_CHARACTER_NOT_IN_REPERTOIRE),
713  errmsg("invalid byte value for encoding \"%s\": 0x%02x",
715  (unsigned char) s[i])));
716  }
717  }
718  return unconstify(char *, s);
719  }
720 
721  /* Fast path if we can use cached conversion function */
722  if (encoding == ClientEncoding->encoding)
723  return perform_default_encoding_conversion(s, len, true);
724 
725  /* General case ... will not work outside transactions */
726  return (char *) pg_do_encoding_conversion((unsigned char *) unconstify(char *, s),
727  len,
728  encoding,
729  DatabaseEncoding->encoding);
730 }
731 
732 /*
733  * Convert server encoding to client encoding.
734  *
735  * See the notes about string conversion functions at the top of this file.
736  */
737 char *
738 pg_server_to_client(const char *s, int len)
739 {
740  return pg_server_to_any(s, len, ClientEncoding->encoding);
741 }
742 
743 /*
744  * Convert server encoding to any encoding.
745  *
746  * See the notes about string conversion functions at the top of this file.
747  */
748 char *
749 pg_server_to_any(const char *s, int len, int encoding)
750 {
751  if (len <= 0)
752  return unconstify(char *, s); /* empty string is always valid */
753 
754  if (encoding == DatabaseEncoding->encoding ||
755  encoding == PG_SQL_ASCII)
756  return unconstify(char *, s); /* assume data is valid */
757 
758  if (DatabaseEncoding->encoding == PG_SQL_ASCII)
759  {
760  /* No conversion is possible, but we must validate the result */
761  (void) pg_verify_mbstr(encoding, s, len, false);
762  return unconstify(char *, s);
763  }
764 
765  /* Fast path if we can use cached conversion function */
766  if (encoding == ClientEncoding->encoding)
767  return perform_default_encoding_conversion(s, len, false);
768 
769  /* General case ... will not work outside transactions */
770  return (char *) pg_do_encoding_conversion((unsigned char *) unconstify(char *, s),
771  len,
772  DatabaseEncoding->encoding,
773  encoding);
774 }
775 
776 /*
777  * Perform default encoding conversion using cached FmgrInfo. Since
778  * this function does not access database at all, it is safe to call
779  * outside transactions. If the conversion has not been set up by
780  * SetClientEncoding(), no conversion is performed.
781  */
782 static char *
783 perform_default_encoding_conversion(const char *src, int len,
784  bool is_client_to_server)
785 {
786  char *result;
787  int src_encoding,
788  dest_encoding;
789  FmgrInfo *flinfo;
790 
791  if (is_client_to_server)
792  {
793  src_encoding = ClientEncoding->encoding;
794  dest_encoding = DatabaseEncoding->encoding;
795  flinfo = ToServerConvProc;
796  }
797  else
798  {
799  src_encoding = DatabaseEncoding->encoding;
800  dest_encoding = ClientEncoding->encoding;
801  flinfo = ToClientConvProc;
802  }
803 
804  if (flinfo == NULL)
805  return unconstify(char *, src);
806 
807  /*
808  * Allocate space for conversion result, being wary of integer overflow.
809  * See comments in pg_do_encoding_conversion.
810  */
811  if ((Size) len >= (MaxAllocHugeSize / (Size) MAX_CONVERSION_GROWTH))
812  ereport(ERROR,
813  (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
814  errmsg("out of memory"),
815  errdetail("String of %d bytes is too long for encoding conversion.",
816  len)));
817 
818  result = (char *)
820  (Size) len * MAX_CONVERSION_GROWTH + 1);
821 
822  FunctionCall6(flinfo,
823  Int32GetDatum(src_encoding),
824  Int32GetDatum(dest_encoding),
825  CStringGetDatum(src),
826  CStringGetDatum(result),
827  Int32GetDatum(len),
828  BoolGetDatum(false));
829 
830  /*
831  * Release extra space if there might be a lot --- see comments in
832  * pg_do_encoding_conversion.
833  */
834  if (len > 1000000)
835  {
836  Size resultlen = strlen(result);
837 
838  if (resultlen >= MaxAllocSize)
839  ereport(ERROR,
840  (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
841  errmsg("out of memory"),
842  errdetail("String of %d bytes is too long for encoding conversion.",
843  len)));
844 
845  result = (char *) repalloc(result, resultlen + 1);
846  }
847 
848  return result;
849 }
850 
851 /*
852  * Convert a single Unicode code point into a string in the server encoding.
853  *
854  * The code point given by "c" is converted and stored at *s, which must
855  * have at least MAX_UNICODE_EQUIVALENT_STRING+1 bytes available.
856  * The output will have a trailing '\0'. Throws error if the conversion
857  * cannot be performed.
858  *
859  * Note that this relies on having previously looked up any required
860  * conversion function. That's partly for speed but mostly because the parser
861  * may call this outside any transaction, or in an aborted transaction.
862  */
863 void
864 pg_unicode_to_server(pg_wchar c, unsigned char *s)
865 {
866  unsigned char c_as_utf8[MAX_MULTIBYTE_CHAR_LEN + 1];
867  int c_as_utf8_len;
868  int server_encoding;
869 
870  /*
871  * Complain if invalid Unicode code point. The choice of errcode here is
872  * debatable, but really our caller should have checked this anyway.
873  */
875  ereport(ERROR,
876  (errcode(ERRCODE_SYNTAX_ERROR),
877  errmsg("invalid Unicode code point")));
878 
879  /* Otherwise, if it's in ASCII range, conversion is trivial */
880  if (c <= 0x7F)
881  {
882  s[0] = (unsigned char) c;
883  s[1] = '\0';
884  return;
885  }
886 
887  /* If the server encoding is UTF-8, we just need to reformat the code */
888  server_encoding = GetDatabaseEncoding();
889  if (server_encoding == PG_UTF8)
890  {
891  unicode_to_utf8(c, s);
892  s[pg_utf_mblen(s)] = '\0';
893  return;
894  }
895 
896  /* For all other cases, we must have a conversion function available */
897  if (Utf8ToServerConvProc == NULL)
898  ereport(ERROR,
899  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
900  errmsg("conversion between %s and %s is not supported",
903 
904  /* Construct UTF-8 source string */
905  unicode_to_utf8(c, c_as_utf8);
906  c_as_utf8_len = pg_utf_mblen(c_as_utf8);
907  c_as_utf8[c_as_utf8_len] = '\0';
908 
909  /* Convert, or throw error if we can't */
910  FunctionCall6(Utf8ToServerConvProc,
912  Int32GetDatum(server_encoding),
913  CStringGetDatum(c_as_utf8),
914  CStringGetDatum(s),
915  Int32GetDatum(c_as_utf8_len),
916  BoolGetDatum(false));
917 }
918 
919 
920 /* convert a multibyte string to a wchar */
921 int
922 pg_mb2wchar(const char *from, pg_wchar *to)
923 {
924  return pg_wchar_table[DatabaseEncoding->encoding].mb2wchar_with_len((const unsigned char *) from, to, strlen(from));
925 }
926 
927 /* convert a multibyte string to a wchar with a limited length */
928 int
929 pg_mb2wchar_with_len(const char *from, pg_wchar *to, int len)
930 {
931  return pg_wchar_table[DatabaseEncoding->encoding].mb2wchar_with_len((const unsigned char *) from, to, len);
932 }
933 
934 /* same, with any encoding */
935 int
937  const char *from, pg_wchar *to, int len)
938 {
939  return pg_wchar_table[encoding].mb2wchar_with_len((const unsigned char *) from, to, len);
940 }
941 
942 /* convert a wchar string to a multibyte */
943 int
944 pg_wchar2mb(const pg_wchar *from, char *to)
945 {
946  return pg_wchar_table[DatabaseEncoding->encoding].wchar2mb_with_len(from, (unsigned char *) to, pg_wchar_strlen(from));
947 }
948 
949 /* convert a wchar string to a multibyte with a limited length */
950 int
951 pg_wchar2mb_with_len(const pg_wchar *from, char *to, int len)
952 {
953  return pg_wchar_table[DatabaseEncoding->encoding].wchar2mb_with_len(from, (unsigned char *) to, len);
954 }
955 
956 /* same, with any encoding */
957 int
959  const pg_wchar *from, char *to, int len)
960 {
961  return pg_wchar_table[encoding].wchar2mb_with_len(from, (unsigned char *) to, len);
962 }
963 
964 /* returns the byte length of a multibyte character */
965 int
966 pg_mblen(const char *mbstr)
967 {
968  return pg_wchar_table[DatabaseEncoding->encoding].mblen((const unsigned char *) mbstr);
969 }
970 
971 /* returns the display length of a multibyte character */
972 int
973 pg_dsplen(const char *mbstr)
974 {
975  return pg_wchar_table[DatabaseEncoding->encoding].dsplen((const unsigned char *) mbstr);
976 }
977 
978 /* returns the length (counted in wchars) of a multibyte string */
979 int
980 pg_mbstrlen(const char *mbstr)
981 {
982  int len = 0;
983 
984  /* optimization for single byte encoding */
986  return strlen(mbstr);
987 
988  while (*mbstr)
989  {
990  mbstr += pg_mblen(mbstr);
991  len++;
992  }
993  return len;
994 }
995 
996 /* returns the length (counted in wchars) of a multibyte string
997  * (not necessarily NULL terminated)
998  */
999 int
1000 pg_mbstrlen_with_len(const char *mbstr, int limit)
1001 {
1002  int len = 0;
1003 
1004  /* optimization for single byte encoding */
1006  return limit;
1007 
1008  while (limit > 0 && *mbstr)
1009  {
1010  int l = pg_mblen(mbstr);
1011 
1012  limit -= l;
1013  mbstr += l;
1014  len++;
1015  }
1016  return len;
1017 }
1018 
1019 /*
1020  * returns the byte length of a multibyte string
1021  * (not necessarily NULL terminated)
1022  * that is no longer than limit.
1023  * this function does not break multibyte character boundary.
1024  */
1025 int
1026 pg_mbcliplen(const char *mbstr, int len, int limit)
1027 {
1028  return pg_encoding_mbcliplen(DatabaseEncoding->encoding, mbstr,
1029  len, limit);
1030 }
1031 
1032 /*
1033  * pg_mbcliplen with specified encoding
1034  */
1035 int
1036 pg_encoding_mbcliplen(int encoding, const char *mbstr,
1037  int len, int limit)
1038 {
1039  mblen_converter mblen_fn;
1040  int clen = 0;
1041  int l;
1042 
1043  /* optimization for single byte encoding */
1044  if (pg_encoding_max_length(encoding) == 1)
1045  return cliplen(mbstr, len, limit);
1046 
1047  mblen_fn = pg_wchar_table[encoding].mblen;
1048 
1049  while (len > 0 && *mbstr)
1050  {
1051  l = (*mblen_fn) ((const unsigned char *) mbstr);
1052  if ((clen + l) > limit)
1053  break;
1054  clen += l;
1055  if (clen == limit)
1056  break;
1057  len -= l;
1058  mbstr += l;
1059  }
1060  return clen;
1061 }
1062 
1063 /*
1064  * Similar to pg_mbcliplen except the limit parameter specifies the
1065  * character length, not the byte length.
1066  */
1067 int
1068 pg_mbcharcliplen(const char *mbstr, int len, int limit)
1069 {
1070  int clen = 0;
1071  int nch = 0;
1072  int l;
1073 
1074  /* optimization for single byte encoding */
1076  return cliplen(mbstr, len, limit);
1077 
1078  while (len > 0 && *mbstr)
1079  {
1080  l = pg_mblen(mbstr);
1081  nch++;
1082  if (nch > limit)
1083  break;
1084  clen += l;
1085  len -= l;
1086  mbstr += l;
1087  }
1088  return clen;
1089 }
1090 
1091 /* mbcliplen for any single-byte encoding */
1092 static int
1093 cliplen(const char *str, int len, int limit)
1094 {
1095  int l = 0;
1096 
1097  len = Min(len, limit);
1098  while (l < len && str[l])
1099  l++;
1100  return l;
1101 }
1102 
1103 void
1105 {
1106  if (!PG_VALID_BE_ENCODING(encoding))
1107  elog(ERROR, "invalid database encoding: %d", encoding);
1108 
1109  DatabaseEncoding = &pg_enc2name_tbl[encoding];
1110  Assert(DatabaseEncoding->encoding == encoding);
1111 }
1112 
1113 void
1115 {
1116  /* Some calls happen before we can elog()! */
1117  Assert(PG_VALID_ENCODING(encoding));
1118 
1119  MessageEncoding = &pg_enc2name_tbl[encoding];
1120  Assert(MessageEncoding->encoding == encoding);
1121 }
1122 
1123 #ifdef ENABLE_NLS
1124 /*
1125  * Make one bind_textdomain_codeset() call, translating a pg_enc to a gettext
1126  * codeset. Fails for MULE_INTERNAL, an encoding unknown to gettext; can also
1127  * fail for gettext-internal causes like out-of-memory.
1128  */
1129 static bool
1130 raw_pg_bind_textdomain_codeset(const char *domainname, int encoding)
1131 {
1132  bool elog_ok = (CurrentMemoryContext != NULL);
1133  int i;
1134 
1135  for (i = 0; pg_enc2gettext_tbl[i].name != NULL; i++)
1136  {
1137  if (pg_enc2gettext_tbl[i].encoding == encoding)
1138  {
1139  if (bind_textdomain_codeset(domainname,
1140  pg_enc2gettext_tbl[i].name) != NULL)
1141  return true;
1142 
1143  if (elog_ok)
1144  elog(LOG, "bind_textdomain_codeset failed");
1145  else
1146  write_stderr("bind_textdomain_codeset failed");
1147 
1148  break;
1149  }
1150  }
1151 
1152  return false;
1153 }
1154 
1155 /*
1156  * Bind a gettext message domain to the codeset corresponding to the database
1157  * encoding. For SQL_ASCII, instead bind to the codeset implied by LC_CTYPE.
1158  * Return the MessageEncoding implied by the new settings.
1159  *
1160  * On most platforms, gettext defaults to the codeset implied by LC_CTYPE.
1161  * When that matches the database encoding, we don't need to do anything. In
1162  * CREATE DATABASE, we enforce or trust that the locale's codeset matches the
1163  * database encoding, except for the C locale. (On Windows, we also permit a
1164  * discrepancy under the UTF8 encoding.) For the C locale, explicitly bind
1165  * gettext to the right codeset.
1166  *
1167  * On Windows, gettext defaults to the Windows ANSI code page. This is a
1168  * convenient departure for software that passes the strings to Windows ANSI
1169  * APIs, but we don't do that. Compel gettext to use database encoding or,
1170  * failing that, the LC_CTYPE encoding as it would on other platforms.
1171  *
1172  * This function is called before elog() and palloc() are usable.
1173  */
1174 int
1175 pg_bind_textdomain_codeset(const char *domainname)
1176 {
1177  bool elog_ok = (CurrentMemoryContext != NULL);
1178  int encoding = GetDatabaseEncoding();
1179  int new_msgenc;
1180 
1181 #ifndef WIN32
1182  const char *ctype = setlocale(LC_CTYPE, NULL);
1183 
1184  if (pg_strcasecmp(ctype, "C") == 0 || pg_strcasecmp(ctype, "POSIX") == 0)
1185 #endif
1186  if (encoding != PG_SQL_ASCII &&
1187  raw_pg_bind_textdomain_codeset(domainname, encoding))
1188  return encoding;
1189 
1190  new_msgenc = pg_get_encoding_from_locale(NULL, elog_ok);
1191  if (new_msgenc < 0)
1192  new_msgenc = PG_SQL_ASCII;
1193 
1194 #ifdef WIN32
1195  if (!raw_pg_bind_textdomain_codeset(domainname, new_msgenc))
1196  /* On failure, the old message encoding remains valid. */
1197  return GetMessageEncoding();
1198 #endif
1199 
1200  return new_msgenc;
1201 }
1202 #endif
1203 
1204 /*
1205  * The database encoding, also called the server encoding, represents the
1206  * encoding of data stored in text-like data types. Affected types include
1207  * cstring, text, varchar, name, xml, and json.
1208  */
1209 int
1211 {
1212  return DatabaseEncoding->encoding;
1213 }
1214 
1215 const char *
1217 {
1218  return DatabaseEncoding->name;
1219 }
1220 
1221 Datum
1223 {
1224  return DirectFunctionCall1(namein, CStringGetDatum(DatabaseEncoding->name));
1225 }
1226 
1227 Datum
1229 {
1230  return DirectFunctionCall1(namein, CStringGetDatum(ClientEncoding->name));
1231 }
1232 
1233 Datum
1235 {
1236  Name s = PG_GETARG_NAME(0);
1237 
1239 }
1240 
1241 Datum
1243 {
1245  const char *encoding_name = pg_encoding_to_char(encoding);
1246 
1247  return DirectFunctionCall1(namein, CStringGetDatum(encoding_name));
1248 }
1249 
1250 /*
1251  * gettext() returns messages in this encoding. This often matches the
1252  * database encoding, but it differs for SQL_ASCII databases, for processes
1253  * not attached to a database, and under a database encoding lacking iconv
1254  * support (MULE_INTERNAL).
1255  */
1256 int
1258 {
1259  return MessageEncoding->encoding;
1260 }
1261 
1262 
1263 /*
1264  * Generic character incrementer function.
1265  *
1266  * Not knowing anything about the properties of the encoding in use, we just
1267  * keep incrementing the last byte until we get a validly-encoded result,
1268  * or we run out of values to try. We don't bother to try incrementing
1269  * higher-order bytes, so there's no growth in runtime for wider characters.
1270  * (If we did try to do that, we'd need to consider the likelihood that 255
1271  * is not a valid final byte in the encoding.)
1272  */
1273 static bool
1274 pg_generic_charinc(unsigned char *charptr, int len)
1275 {
1276  unsigned char *lastbyte = charptr + len - 1;
1277  mbchar_verifier mbverify;
1278 
1279  /* We can just invoke the character verifier directly. */
1281 
1282  while (*lastbyte < (unsigned char) 255)
1283  {
1284  (*lastbyte)++;
1285  if ((*mbverify) (charptr, len) == len)
1286  return true;
1287  }
1288 
1289  return false;
1290 }
1291 
1292 /*
1293  * UTF-8 character incrementer function.
1294  *
1295  * For a one-byte character less than 0x7F, we just increment the byte.
1296  *
1297  * For a multibyte character, every byte but the first must fall between 0x80
1298  * and 0xBF; and the first byte must be between 0xC0 and 0xF4. We increment
1299  * the last byte that's not already at its maximum value. If we can't find a
1300  * byte that's less than the maximum allowable value, we simply fail. We also
1301  * need some special-case logic to skip regions used for surrogate pair
1302  * handling, as those should not occur in valid UTF-8.
1303  *
1304  * Note that we don't reset lower-order bytes back to their minimums, since
1305  * we can't afford to make an exhaustive search (see make_greater_string).
1306  */
1307 static bool
1308 pg_utf8_increment(unsigned char *charptr, int length)
1309 {
1310  unsigned char a;
1311  unsigned char limit;
1312 
1313  switch (length)
1314  {
1315  default:
1316  /* reject lengths 5 and 6 for now */
1317  return false;
1318  case 4:
1319  a = charptr[3];
1320  if (a < 0xBF)
1321  {
1322  charptr[3]++;
1323  break;
1324  }
1325  /* FALL THRU */
1326  case 3:
1327  a = charptr[2];
1328  if (a < 0xBF)
1329  {
1330  charptr[2]++;
1331  break;
1332  }
1333  /* FALL THRU */
1334  case 2:
1335  a = charptr[1];
1336  switch (*charptr)
1337  {
1338  case 0xED:
1339  limit = 0x9F;
1340  break;
1341  case 0xF4:
1342  limit = 0x8F;
1343  break;
1344  default:
1345  limit = 0xBF;
1346  break;
1347  }
1348  if (a < limit)
1349  {
1350  charptr[1]++;
1351  break;
1352  }
1353  /* FALL THRU */
1354  case 1:
1355  a = *charptr;
1356  if (a == 0x7F || a == 0xDF || a == 0xEF || a == 0xF4)
1357  return false;
1358  charptr[0]++;
1359  break;
1360  }
1361 
1362  return true;
1363 }
1364 
1365 /*
1366  * EUC-JP character incrementer function.
1367  *
1368  * If the sequence starts with SS2 (0x8e), it must be a two-byte sequence
1369  * representing JIS X 0201 characters with the second byte ranging between
1370  * 0xa1 and 0xdf. We just increment the last byte if it's less than 0xdf,
1371  * and otherwise rewrite the whole sequence to 0xa1 0xa1.
1372  *
1373  * If the sequence starts with SS3 (0x8f), it must be a three-byte sequence
1374  * in which the last two bytes range between 0xa1 and 0xfe. The last byte
1375  * is incremented if possible, otherwise the second-to-last byte.
1376  *
1377  * If the sequence starts with a value other than the above and its MSB
1378  * is set, it must be a two-byte sequence representing JIS X 0208 characters
1379  * with both bytes ranging between 0xa1 and 0xfe. The last byte is
1380  * incremented if possible, otherwise the second-to-last byte.
1381  *
1382  * Otherwise, the sequence is a single-byte ASCII character. It is
1383  * incremented up to 0x7f.
1384  */
1385 static bool
1386 pg_eucjp_increment(unsigned char *charptr, int length)
1387 {
1388  unsigned char c1,
1389  c2;
1390  int i;
1391 
1392  c1 = *charptr;
1393 
1394  switch (c1)
1395  {
1396  case SS2: /* JIS X 0201 */
1397  if (length != 2)
1398  return false;
1399 
1400  c2 = charptr[1];
1401 
1402  if (c2 >= 0xdf)
1403  charptr[0] = charptr[1] = 0xa1;
1404  else if (c2 < 0xa1)
1405  charptr[1] = 0xa1;
1406  else
1407  charptr[1]++;
1408  break;
1409 
1410  case SS3: /* JIS X 0212 */
1411  if (length != 3)
1412  return false;
1413 
1414  for (i = 2; i > 0; i--)
1415  {
1416  c2 = charptr[i];
1417  if (c2 < 0xa1)
1418  {
1419  charptr[i] = 0xa1;
1420  return true;
1421  }
1422  else if (c2 < 0xfe)
1423  {
1424  charptr[i]++;
1425  return true;
1426  }
1427  }
1428 
1429  /* Out of 3-byte code region */
1430  return false;
1431 
1432  default:
1433  if (IS_HIGHBIT_SET(c1)) /* JIS X 0208? */
1434  {
1435  if (length != 2)
1436  return false;
1437 
1438  for (i = 1; i >= 0; i--)
1439  {
1440  c2 = charptr[i];
1441  if (c2 < 0xa1)
1442  {
1443  charptr[i] = 0xa1;
1444  return true;
1445  }
1446  else if (c2 < 0xfe)
1447  {
1448  charptr[i]++;
1449  return true;
1450  }
1451  }
1452 
1453  /* Out of 2 byte code region */
1454  return false;
1455  }
1456  else
1457  { /* ASCII, single byte */
1458  if (c1 > 0x7e)
1459  return false;
1460  (*charptr)++;
1461  }
1462  break;
1463  }
1464 
1465  return true;
1466 }
1467 
1468 /*
1469  * get the character incrementer for the encoding for the current database
1470  */
1473 {
1474  /*
1475  * Eventually it might be best to add a field to pg_wchar_table[], but for
1476  * now we just use a switch.
1477  */
1478  switch (GetDatabaseEncoding())
1479  {
1480  case PG_UTF8:
1481  return pg_utf8_increment;
1482 
1483  case PG_EUC_JP:
1484  return pg_eucjp_increment;
1485 
1486  default:
1487  return pg_generic_charinc;
1488  }
1489 }
1490 
1491 /*
1492  * fetch maximum length of the encoding for the current database
1493  */
1494 int
1496 {
1498 }
1499 
1500 /*
1501  * Verify mbstr to make sure that it is validly encoded in the current
1502  * database encoding. Otherwise same as pg_verify_mbstr().
1503  */
1504 bool
1505 pg_verifymbstr(const char *mbstr, int len, bool noError)
1506 {
1507  return pg_verify_mbstr(GetDatabaseEncoding(), mbstr, len, noError);
1508 }
1509 
1510 /*
1511  * Verify mbstr to make sure that it is validly encoded in the specified
1512  * encoding.
1513  */
1514 bool
1515 pg_verify_mbstr(int encoding, const char *mbstr, int len, bool noError)
1516 {
1517  int oklen;
1518 
1519  Assert(PG_VALID_ENCODING(encoding));
1520 
1521  oklen = pg_wchar_table[encoding].mbverifystr((const unsigned char *) mbstr, len);
1522  if (oklen != len)
1523  {
1524  if (noError)
1525  return false;
1526  report_invalid_encoding(encoding, mbstr + oklen, len - oklen);
1527  }
1528  return true;
1529 }
1530 
1531 /*
1532  * Verify mbstr to make sure that it is validly encoded in the specified
1533  * encoding.
1534  *
1535  * mbstr is not necessarily zero terminated; length of mbstr is
1536  * specified by len.
1537  *
1538  * If OK, return length of string in the encoding.
1539  * If a problem is found, return -1 when noError is
1540  * true; when noError is false, ereport() a descriptive message.
1541  *
1542  * Note: We cannot use the faster encoding-specific mbverifystr() function
1543  * here, because we need to count the number of characters in the string.
1544  */
1545 int
1546 pg_verify_mbstr_len(int encoding, const char *mbstr, int len, bool noError)
1547 {
1548  mbchar_verifier mbverifychar;
1549  int mb_len;
1550 
1551  Assert(PG_VALID_ENCODING(encoding));
1552 
1553  /*
1554  * In single-byte encodings, we need only reject nulls (\0).
1555  */
1556  if (pg_encoding_max_length(encoding) <= 1)
1557  {
1558  const char *nullpos = memchr(mbstr, 0, len);
1559 
1560  if (nullpos == NULL)
1561  return len;
1562  if (noError)
1563  return -1;
1564  report_invalid_encoding(encoding, nullpos, 1);
1565  }
1566 
1567  /* fetch function pointer just once */
1568  mbverifychar = pg_wchar_table[encoding].mbverifychar;
1569 
1570  mb_len = 0;
1571 
1572  while (len > 0)
1573  {
1574  int l;
1575 
1576  /* fast path for ASCII-subset characters */
1577  if (!IS_HIGHBIT_SET(*mbstr))
1578  {
1579  if (*mbstr != '\0')
1580  {
1581  mb_len++;
1582  mbstr++;
1583  len--;
1584  continue;
1585  }
1586  if (noError)
1587  return -1;
1588  report_invalid_encoding(encoding, mbstr, len);
1589  }
1590 
1591  l = (*mbverifychar) ((const unsigned char *) mbstr, len);
1592 
1593  if (l < 0)
1594  {
1595  if (noError)
1596  return -1;
1597  report_invalid_encoding(encoding, mbstr, len);
1598  }
1599 
1600  mbstr += l;
1601  len -= l;
1602  mb_len++;
1603  }
1604  return mb_len;
1605 }
1606 
1607 /*
1608  * check_encoding_conversion_args: check arguments of a conversion function
1609  *
1610  * "expected" arguments can be either an encoding ID or -1 to indicate that
1611  * the caller will check whether it accepts the ID.
1612  *
1613  * Note: the errors here are not really user-facing, so elog instead of
1614  * ereport seems sufficient. Also, we trust that the "expected" encoding
1615  * arguments are valid encoding IDs, but we don't trust the actuals.
1616  */
1617 void
1619  int dest_encoding,
1620  int len,
1621  int expected_src_encoding,
1622  int expected_dest_encoding)
1623 {
1624  if (!PG_VALID_ENCODING(src_encoding))
1625  elog(ERROR, "invalid source encoding ID: %d", src_encoding);
1626  if (src_encoding != expected_src_encoding && expected_src_encoding >= 0)
1627  elog(ERROR, "expected source encoding \"%s\", but got \"%s\"",
1628  pg_enc2name_tbl[expected_src_encoding].name,
1629  pg_enc2name_tbl[src_encoding].name);
1630  if (!PG_VALID_ENCODING(dest_encoding))
1631  elog(ERROR, "invalid destination encoding ID: %d", dest_encoding);
1632  if (dest_encoding != expected_dest_encoding && expected_dest_encoding >= 0)
1633  elog(ERROR, "expected destination encoding \"%s\", but got \"%s\"",
1634  pg_enc2name_tbl[expected_dest_encoding].name,
1635  pg_enc2name_tbl[dest_encoding].name);
1636  if (len < 0)
1637  elog(ERROR, "encoding conversion length must not be negative");
1638 }
1639 
1640 /*
1641  * report_invalid_encoding: complain about invalid multibyte character
1642  *
1643  * note: len is remaining length of string, not length of character;
1644  * len must be greater than zero, as we always examine the first byte.
1645  */
1646 void
1647 report_invalid_encoding(int encoding, const char *mbstr, int len)
1648 {
1649  int l = pg_encoding_mblen(encoding, mbstr);
1650  char buf[8 * 5 + 1];
1651  char *p = buf;
1652  int j,
1653  jlimit;
1654 
1655  jlimit = Min(l, len);
1656  jlimit = Min(jlimit, 8); /* prevent buffer overrun */
1657 
1658  for (j = 0; j < jlimit; j++)
1659  {
1660  p += sprintf(p, "0x%02x", (unsigned char) mbstr[j]);
1661  if (j < jlimit - 1)
1662  p += sprintf(p, " ");
1663  }
1664 
1665  ereport(ERROR,
1666  (errcode(ERRCODE_CHARACTER_NOT_IN_REPERTOIRE),
1667  errmsg("invalid byte sequence for encoding \"%s\": %s",
1668  pg_enc2name_tbl[encoding].name,
1669  buf)));
1670 }
1671 
1672 /*
1673  * report_untranslatable_char: complain about untranslatable character
1674  *
1675  * note: len is remaining length of string, not length of character;
1676  * len must be greater than zero, as we always examine the first byte.
1677  */
1678 void
1679 report_untranslatable_char(int src_encoding, int dest_encoding,
1680  const char *mbstr, int len)
1681 {
1682  int l = pg_encoding_mblen(src_encoding, mbstr);
1683  char buf[8 * 5 + 1];
1684  char *p = buf;
1685  int j,
1686  jlimit;
1687 
1688  jlimit = Min(l, len);
1689  jlimit = Min(jlimit, 8); /* prevent buffer overrun */
1690 
1691  for (j = 0; j < jlimit; j++)
1692  {
1693  p += sprintf(p, "0x%02x", (unsigned char) mbstr[j]);
1694  if (j < jlimit - 1)
1695  p += sprintf(p, " ");
1696  }
1697 
1698  ereport(ERROR,
1699  (errcode(ERRCODE_UNTRANSLATABLE_CHARACTER),
1700  errmsg("character with byte sequence %s in encoding \"%s\" has no equivalent in encoding \"%s\"",
1701  buf,
1702  pg_enc2name_tbl[src_encoding].name,
1703  pg_enc2name_tbl[dest_encoding].name)));
1704 }
1705 
1706 
1707 #ifdef WIN32
1708 /*
1709  * Convert from MessageEncoding to a palloc'ed, null-terminated utf16
1710  * string. The character length is also passed to utf16len if not
1711  * null. Returns NULL iff failed. Before MessageEncoding initialization, "str"
1712  * should be ASCII-only; this will function as though MessageEncoding is UTF8.
1713  */
1714 WCHAR *
1715 pgwin32_message_to_UTF16(const char *str, int len, int *utf16len)
1716 {
1717  int msgenc = GetMessageEncoding();
1718  WCHAR *utf16;
1719  int dstlen;
1720  UINT codepage;
1721 
1722  if (msgenc == PG_SQL_ASCII)
1723  /* No conversion is possible, and SQL_ASCII is never utf16. */
1724  return NULL;
1725 
1726  codepage = pg_enc2name_tbl[msgenc].codepage;
1727 
1728  /*
1729  * Use MultiByteToWideChar directly if there is a corresponding codepage,
1730  * or double conversion through UTF8 if not. Double conversion is needed,
1731  * for example, in an ENCODING=LATIN8, LC_CTYPE=C database.
1732  */
1733  if (codepage != 0)
1734  {
1735  utf16 = (WCHAR *) palloc(sizeof(WCHAR) * (len + 1));
1736  dstlen = MultiByteToWideChar(codepage, 0, str, len, utf16, len);
1737  utf16[dstlen] = (WCHAR) 0;
1738  }
1739  else
1740  {
1741  char *utf8;
1742 
1743  /*
1744  * XXX pg_do_encoding_conversion() requires a transaction. In the
1745  * absence of one, hope for the input to be valid UTF8.
1746  */
1747  if (IsTransactionState())
1748  {
1749  utf8 = (char *) pg_do_encoding_conversion((unsigned char *) str,
1750  len,
1751  msgenc,
1752  PG_UTF8);
1753  if (utf8 != str)
1754  len = strlen(utf8);
1755  }
1756  else
1757  utf8 = (char *) str;
1758 
1759  utf16 = (WCHAR *) palloc(sizeof(WCHAR) * (len + 1));
1760  dstlen = MultiByteToWideChar(CP_UTF8, 0, utf8, len, utf16, len);
1761  utf16[dstlen] = (WCHAR) 0;
1762 
1763  if (utf8 != str)
1764  pfree(utf8);
1765  }
1766 
1767  if (dstlen == 0 && len > 0)
1768  {
1769  pfree(utf16);
1770  return NULL; /* error */
1771  }
1772 
1773  if (utf16len)
1774  *utf16len = dstlen;
1775  return utf16;
1776 }
1777 
1778 #endif /* WIN32 */
#define NIL
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