lib/util/charset/iconv.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    minimal iconv implementation
   4    Copyright (C) Andrew Tridgell 2001
   5    Copyright (C) Jelmer Vernooij 2002
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "../lib/util/dlinklist.h"
  23 #include "system/iconv.h"
  24 #include "system/filesys.h"
  25
  26
  27 /**
  28  * @file
  29  *
  30  * @brief Samba wrapper/stub for iconv character set conversion.
  31  *
  32  * iconv is the XPG2 interface for converting between character
  33  * encodings.  This file provides a Samba wrapper around it, and also
  34  * a simple reimplementation that is used if the system does not
  35  * implement iconv.
  36  *
  37  * Samba only works with encodings that are supersets of ASCII: ascii
  38  * characters like whitespace can be tested for directly, multibyte
  39  * sequences start with a byte with the high bit set, and strings are
  40  * terminated by a nul byte.
  41  *
  42  * Note that the only function provided by iconv is conversion between
  43  * characters.  It doesn't directly support operations like
  44  * uppercasing or comparison.  We have to convert to UTF-16LE and
  45  * compare there.
  46  *
  47  * @sa Samba Developers Guide
  48  **/
  49
  50 static size_t ascii_pull  (void *,const char **, size_t *, char **, size_t *);
  51 static size_t ascii_push  (void *,const char **, size_t *, char **, size_t *);
  52 static size_t utf8_pull   (void *,const char **, size_t *, char **, size_t *);
  53 static size_t utf8_push   (void *,const char **, size_t *, char **, size_t *);
  54 static size_t utf16_munged_pull(void *,const char **, size_t *, char **, size_t *);
  55 static size_t ucs2hex_pull(void *,const char **, size_t *, char **, size_t *);
  56 static size_t ucs2hex_push(void *,const char **, size_t *, char **, size_t *);
  57 static size_t iconv_copy  (void *,const char **, size_t *, char **, size_t *);
  58 static size_t iconv_swab  (void *,const char **, size_t *, char **, size_t *);
  59
  60 static const struct charset_functions builtin_functions[] = {
  61         /* windows is closest to UTF-16 */
  62         {"UCS-2LE",  iconv_copy, iconv_copy},
  63         {"UTF-16LE",  iconv_copy, iconv_copy},
  64         {"UCS-2BE",  iconv_swab, iconv_swab},
  65         {"UTF-16BE",  iconv_swab, iconv_swab},
  66
  67         /* we include the UTF-8 alias to cope with differing locale settings */
  68         {"UTF8",   utf8_pull,  utf8_push},
  69         {"UTF-8",   utf8_pull,  utf8_push},
  70
  71         /* this handles the munging needed for String2Key */
  72         {"UTF16_MUNGED",   utf16_munged_pull,  iconv_copy},
  73
  74         {"ASCII", ascii_pull, ascii_push},
  75         {"UCS2-HEX", ucs2hex_pull, ucs2hex_push}
  76 };
  77
  78 static struct charset_functions *charsets = NULL;
  79
  80 bool charset_register_backend(const void *_funcs)
  81 {
  82         struct charset_functions *funcs = (struct charset_functions *)memdup(_funcs,sizeof(struct charset_functions));
  83         struct charset_functions *c;
  84
  85         /* Check whether we already have this charset... */
  86         for (c = charsets; c != NULL; c = c->next) {
  87                 if(!strcasecmp(c->name, funcs->name)) {
  88                         DEBUG(2, ("Duplicate charset %s, not registering\n", funcs->name));
  89                         return false;
  90                 }
  91         }
  92
  93         funcs->next = funcs->prev = NULL;
  94         DLIST_ADD(charsets, funcs);
  95         return true;
  96 }
  97
  98 #ifdef HAVE_NATIVE_ICONV
  99 /* if there was an error then reset the internal state,
 100    this ensures that we don't have a shift state remaining for
 101    character sets like SJIS */
 102 static size_t sys_iconv(void *cd,
 103                         const char **inbuf, size_t *inbytesleft,
 104                         char **outbuf, size_t *outbytesleft)
 105 {
 106         size_t ret = iconv((iconv_t)cd,
 107                            discard_const_p(char *, inbuf), inbytesleft,
 108                            outbuf, outbytesleft);
 109         if (ret == (size_t)-1) iconv(cd, NULL, NULL, NULL, NULL);
 110         return ret;
 111 }
 112 #endif
 113
 114 /**
 115  * This is a simple portable iconv() implementaion.
 116  *
 117  * It only knows about a very small number of character sets - just
 118  * enough that Samba works on systems that don't have iconv.
 119  **/
 120 _PUBLIC_ size_t smb_iconv(smb_iconv_t cd,
 121                  const char **inbuf, size_t *inbytesleft,
 122                  char **outbuf, size_t *outbytesleft)
 123 {
 124         char cvtbuf[2048];
 125         size_t bufsize;
 126
 127         /* in many cases we can go direct */
 128         if (cd->direct) {
 129                 return cd->direct(cd->cd_direct,
 130                                   inbuf, inbytesleft, outbuf, outbytesleft);
 131         }
 132
 133
 134         /* otherwise we have to do it chunks at a time */
 135         while (*inbytesleft > 0) {
 136                 char *bufp1 = cvtbuf;
 137                 const char *bufp2 = cvtbuf;
 138
 139                 bufsize = sizeof(cvtbuf);
 140
 141                 if (cd->pull(cd->cd_pull,
 142                              inbuf, inbytesleft, &bufp1, &bufsize) == -1
 143                     && errno != E2BIG) return -1;
 144
 145                 bufsize = sizeof(cvtbuf) - bufsize;
 146
 147                 if (cd->push(cd->cd_push,
 148                              &bufp2, &bufsize,
 149                              outbuf, outbytesleft) == -1) return -1;
 150         }
 151
 152         return 0;
 153 }
 154
 155 static bool is_utf16(const char *name)
 156 {
 157         return strcasecmp(name, "UCS-2LE") == 0 ||
 158                 strcasecmp(name, "UTF-16LE") == 0;
 159 }
 160
 161 int smb_iconv_t_destructor(smb_iconv_t hwd)
 162 {
 163 #ifdef HAVE_NATIVE_ICONV
 164         if (hwd->cd_pull != NULL && hwd->cd_pull != (iconv_t)-1)
 165                 iconv_close(hwd->cd_pull);
 166         if (hwd->cd_push != NULL && hwd->cd_push != (iconv_t)-1)
 167                 iconv_close(hwd->cd_push);
 168         if (hwd->cd_direct != NULL && hwd->cd_direct != (iconv_t)-1)
 169                 iconv_close(hwd->cd_direct);
 170 #endif
 171
 172         return 0;
 173 }
 174
 175 _PUBLIC_ smb_iconv_t smb_iconv_open_ex(TALLOC_CTX *mem_ctx, const char *tocode,
 176                               const char *fromcode, bool native_iconv)
 177 {
 178         smb_iconv_t ret;
 179         const struct charset_functions *from=NULL, *to=NULL;
 180         int i;
 181
 182         ret = (smb_iconv_t)talloc_named(mem_ctx,
 183                                         sizeof(*ret),
 184                                         "iconv(%s,%s)", tocode, fromcode);
 185         if (!ret) {
 186                 errno = ENOMEM;
 187                 return (smb_iconv_t)-1;
 188         }
 189         memset(ret, 0, sizeof(*ret));
 190         talloc_set_destructor(ret, smb_iconv_t_destructor);
 191
 192         /* check for the simplest null conversion */
 193         if (strcmp(fromcode, tocode) == 0) {
 194                 ret->direct = iconv_copy;
 195                 return ret;
 196         }
 197
 198         for (i=0;i<ARRAY_SIZE(builtin_functions);i++) {
 199                 if (strcasecmp(fromcode, builtin_functions[i].name) == 0) {
 200                         from = &builtin_functions[i];
 201                 }
 202                 if (strcasecmp(tocode, builtin_functions[i].name) == 0) {
 203                         to = &builtin_functions[i];
 204                 }
 205         }
 206
 207         if (from == NULL) {
 208                 for (from=charsets; from; from=from->next) {
 209                         if (strcasecmp(from->name, fromcode) == 0) break;
 210                 }
 211         }
 212
 213         if (to == NULL) {
 214                 for (to=charsets; to; to=to->next) {
 215                         if (strcasecmp(to->name, tocode) == 0) break;
 216                 }
 217         }
 218
 219 #ifdef HAVE_NATIVE_ICONV
 220         if ((!from || !to) && !native_iconv) {
 221                 goto failed;
 222         }
 223         if (!from) {
 224                 ret->pull = sys_iconv;
 225                 ret->cd_pull = iconv_open("UTF-16LE", fromcode);
 226                 if (ret->cd_pull == (iconv_t)-1)
 227                         ret->cd_pull = iconv_open("UCS-2LE", fromcode);
 228                 if (ret->cd_pull == (iconv_t)-1) goto failed;
 229         }
 230
 231         if (!to) {
 232                 ret->push = sys_iconv;
 233                 ret->cd_push = iconv_open(tocode, "UTF-16LE");
 234                 if (ret->cd_push == (iconv_t)-1)
 235                         ret->cd_push = iconv_open(tocode, "UCS-2LE");
 236                 if (ret->cd_push == (iconv_t)-1) goto failed;
 237         }
 238 #else
 239         if (!from || !to) {
 240                 goto failed;
 241         }
 242 #endif
 243
 244         /* check for conversion to/from ucs2 */
 245         if (is_utf16(fromcode) && to) {
 246                 ret->direct = to->push;
 247                 return ret;
 248         }
 249         if (is_utf16(tocode) && from) {
 250                 ret->direct = from->pull;
 251                 return ret;
 252         }
 253
 254 #ifdef HAVE_NATIVE_ICONV
 255         if (is_utf16(fromcode)) {
 256                 ret->direct = sys_iconv;
 257                 ret->cd_direct = ret->cd_push;
 258                 ret->cd_push = NULL;
 259                 return ret;
 260         }
 261         if (is_utf16(tocode)) {
 262                 ret->direct = sys_iconv;
 263                 /* could be set just above - so we need to close iconv */
 264                 if (ret->cd_direct != NULL && ret->cd_direct != (iconv_t)-1)
 265                         iconv_close(ret->cd_direct);
 266                 ret->cd_direct = ret->cd_pull;
 267                 ret->cd_pull = NULL;
 268                 return ret;
 269         }
 270 #endif
 271
 272         /* the general case has to go via a buffer */
 273         if (!ret->pull) ret->pull = from->pull;
 274         if (!ret->push) ret->push = to->push;
 275         return ret;
 276
 277 failed:
 278         talloc_free(ret);
 279         errno = EINVAL;
 280         return (smb_iconv_t)-1;
 281 }
 282
 283 /*
 284   simple iconv_open() wrapper
 285  */
 286 _PUBLIC_ smb_iconv_t smb_iconv_open(const char *tocode, const char *fromcode)
 287 {
 288         return smb_iconv_open_ex(talloc_autofree_context(), tocode, fromcode, true);
 289 }
 290
 291 /*
 292   simple iconv_close() wrapper
 293 */
 294 _PUBLIC_ int smb_iconv_close(smb_iconv_t cd)
 295 {
 296         talloc_free(cd);
 297         return 0;
 298 }
 299
 300
 301 /**********************************************************************
 302  the following functions implement the builtin character sets in Samba
 303  and also the "test" character sets that are designed to test
 304  multi-byte character set support for english users
 305 ***********************************************************************/
 306 static size_t ascii_pull(void *cd, const char **inbuf, size_t *inbytesleft,
 307                          char **outbuf, size_t *outbytesleft)
 308 {
 309         while (*inbytesleft >= 1 && *outbytesleft >= 2) {
 310                 (*outbuf)[0] = (*inbuf)[0];
 311                 (*outbuf)[1] = 0;
 312                 (*inbytesleft)  -= 1;
 313                 (*outbytesleft) -= 2;
 314                 (*inbuf)  += 1;
 315                 (*outbuf) += 2;
 316         }
 317
 318         if (*inbytesleft > 0) {
 319                 errno = E2BIG;
 320                 return -1;
 321         }
 322
 323         return 0;
 324 }
 325
 326 static size_t ascii_push(void *cd, const char **inbuf, size_t *inbytesleft,
 327                          char **outbuf, size_t *outbytesleft)
 328 {
 329         int ir_count=0;
 330
 331         while (*inbytesleft >= 2 && *outbytesleft >= 1) {
 332                 (*outbuf)[0] = (*inbuf)[0] & 0x7F;
 333                 if ((*inbuf)[1]) ir_count++;
 334                 (*inbytesleft)  -= 2;
 335                 (*outbytesleft) -= 1;
 336                 (*inbuf)  += 2;
 337                 (*outbuf) += 1;
 338         }
 339
 340         if (*inbytesleft == 1) {
 341                 errno = EINVAL;
 342                 return -1;
 343         }
 344
 345         if (*inbytesleft > 1) {
 346                 errno = E2BIG;
 347                 return -1;
 348         }
 349
 350         return ir_count;
 351 }
 352
 353
 354 static size_t ucs2hex_pull(void *cd, const char **inbuf, size_t *inbytesleft,
 355                          char **outbuf, size_t *outbytesleft)
 356 {
 357         while (*inbytesleft >= 1 && *outbytesleft >= 2) {
 358                 unsigned int v;
 359
 360                 if ((*inbuf)[0] != '@') {
 361                         /* seven bit ascii case */
 362                         (*outbuf)[0] = (*inbuf)[0];
 363                         (*outbuf)[1] = 0;
 364                         (*inbytesleft)  -= 1;
 365                         (*outbytesleft) -= 2;
 366                         (*inbuf)  += 1;
 367                         (*outbuf) += 2;
 368                         continue;
 369                 }
 370                 /* it's a hex character */
 371                 if (*inbytesleft < 5) {
 372                         errno = EINVAL;
 373                         return -1;
 374                 }
 375
 376                 if (sscanf(&(*inbuf)[1], "%04x", &v) != 1) {
 377                         errno = EILSEQ;
 378                         return -1;
 379                 }
 380
 381                 (*outbuf)[0] = v&0xff;
 382                 (*outbuf)[1] = v>>8;
 383                 (*inbytesleft)  -= 5;
 384                 (*outbytesleft) -= 2;
 385                 (*inbuf)  += 5;
 386                 (*outbuf) += 2;
 387         }
 388
 389         if (*inbytesleft > 0) {
 390                 errno = E2BIG;
 391                 return -1;
 392         }
 393
 394         return 0;
 395 }
 396
 397 static size_t ucs2hex_push(void *cd, const char **inbuf, size_t *inbytesleft,
 398                            char **outbuf, size_t *outbytesleft)
 399 {
 400         while (*inbytesleft >= 2 && *outbytesleft >= 1) {
 401                 char buf[6];
 402
 403                 if ((*inbuf)[1] == 0 &&
 404                     ((*inbuf)[0] & 0x80) == 0 &&
 405                     (*inbuf)[0] != '@') {
 406                         (*outbuf)[0] = (*inbuf)[0];
 407                         (*inbytesleft)  -= 2;
 408                         (*outbytesleft) -= 1;
 409                         (*inbuf)  += 2;
 410                         (*outbuf) += 1;
 411                         continue;
 412                 }
 413                 if (*outbytesleft < 5) {
 414                         errno = E2BIG;
 415                         return -1;
 416                 }
 417                 snprintf(buf, 6, "@%04x", SVAL(*inbuf, 0));
 418                 memcpy(*outbuf, buf, 5);
 419                 (*inbytesleft)  -= 2;
 420                 (*outbytesleft) -= 5;
 421                 (*inbuf)  += 2;
 422                 (*outbuf) += 5;
 423         }
 424
 425         if (*inbytesleft == 1) {
 426                 errno = EINVAL;
 427                 return -1;
 428         }
 429
 430         if (*inbytesleft > 1) {
 431                 errno = E2BIG;
 432                 return -1;
 433         }
 434
 435         return 0;
 436 }
 437
 438 static size_t iconv_swab(void *cd, const char **inbuf, size_t *inbytesleft,
 439                          char **outbuf, size_t *outbytesleft)
 440 {
 441         int n;
 442
 443         n = MIN(*inbytesleft, *outbytesleft);
 444
 445         swab(*inbuf, *outbuf, (n&~1));
 446         if (n&1) {
 447                 (*outbuf)[n-1] = 0;
 448         }
 449
 450         (*inbytesleft) -= n;
 451         (*outbytesleft) -= n;
 452         (*inbuf) += n;
 453         (*outbuf) += n;
 454
 455         if (*inbytesleft > 0) {
 456                 errno = E2BIG;
 457                 return -1;
 458         }
 459
 460         return 0;
 461 }
 462
 463
 464 static size_t iconv_copy(void *cd, const char **inbuf, size_t *inbytesleft,
 465                          char **outbuf, size_t *outbytesleft)
 466 {
 467         int n;
 468
 469         n = MIN(*inbytesleft, *outbytesleft);
 470
 471         memmove(*outbuf, *inbuf, n);
 472
 473         (*inbytesleft) -= n;
 474         (*outbytesleft) -= n;
 475         (*inbuf) += n;
 476         (*outbuf) += n;
 477
 478         if (*inbytesleft > 0) {
 479                 errno = E2BIG;
 480                 return -1;
 481         }
 482
 483         return 0;
 484 }
 485
 486 /*
 487   this takes a UTF8 sequence and produces a UTF16 sequence
 488  */
 489 static size_t utf8_pull(void *cd, const char **inbuf, size_t *inbytesleft,
 490                          char **outbuf, size_t *outbytesleft)
 491 {
 492         size_t in_left=*inbytesleft, out_left=*outbytesleft;
 493         const uint8_t *c = (const uint8_t *)*inbuf;
 494         uint8_t *uc = (uint8_t *)*outbuf;
 495
 496         while (in_left >= 1 && out_left >= 2) {
 497                 if ((c[0] & 0x80) == 0) {
 498                         uc[0] = c[0];
 499                         uc[1] = 0;
 500                         c  += 1;
 501                         in_left  -= 1;
 502                         out_left -= 2;
 503                         uc += 2;
 504                         continue;
 505                 }
 506
 507                 if ((c[0] & 0xe0) == 0xc0) {
 508                         if (in_left < 2 ||
 509                             (c[1] & 0xc0) != 0x80) {
 510                                 errno = EILSEQ;
 511                                 goto error;
 512                         }
 513                         uc[1] = (c[0]>>2) & 0x7;
 514                         uc[0] = (c[0]<<6) | (c[1]&0x3f);
 515                         c  += 2;
 516                         in_left  -= 2;
 517                         out_left -= 2;
 518                         uc += 2;
 519                         continue;
 520                 }
 521
 522                 if ((c[0] & 0xf0) == 0xe0) {
 523                         if (in_left < 3 ||
 524                             (c[1] & 0xc0) != 0x80 ||
 525                             (c[2] & 0xc0) != 0x80) {
 526                                 errno = EILSEQ;
 527                                 goto error;
 528                         }
 529                         uc[1] = ((c[0]&0xF)<<4) | ((c[1]>>2)&0xF);
 530                         uc[0] = (c[1]<<6) | (c[2]&0x3f);
 531                         c  += 3;
 532                         in_left  -= 3;
 533                         out_left -= 2;
 534                         uc += 2;
 535                         continue;
 536                 }
 537
 538                 if ((c[0] & 0xf8) == 0xf0) {
 539                         unsigned int codepoint;
 540                         if (in_left < 4 ||
 541                             (c[1] & 0xc0) != 0x80 ||
 542                             (c[2] & 0xc0) != 0x80 ||
 543                             (c[3] & 0xc0) != 0x80) {
 544                                 errno = EILSEQ;
 545                                 goto error;
 546                         }
 547                         codepoint =
 548                                 (c[3]&0x3f) |
 549                                 ((c[2]&0x3f)<<6) |
 550                                 ((c[1]&0x3f)<<12) |
 551                                 ((c[0]&0x7)<<18);
 552                         if (codepoint < 0x10000) {
 553                                 /* accept UTF-8 characters that are not
 554                                    minimally packed, but pack the result */
 555                                 uc[0] = (codepoint & 0xFF);
 556                                 uc[1] = (codepoint >> 8);
 557                                 c += 4;
 558                                 in_left -= 4;
 559                                 out_left -= 2;
 560                                 uc += 2;
 561                                 continue;
 562                         }
 563
 564                         codepoint -= 0x10000;
 565
 566                         if (out_left < 4) {
 567                                 errno = E2BIG;
 568                                 goto error;
 569                         }
 570
 571                         uc[0] = (codepoint>>10) & 0xFF;
 572                         uc[1] = (codepoint>>18) | 0xd8;
 573                         uc[2] = codepoint & 0xFF;
 574                         uc[3] = ((codepoint>>8) & 0x3) | 0xdc;
 575                         c  += 4;
 576                         in_left  -= 4;
 577                         out_left -= 4;
 578                         uc += 4;
 579                         continue;
 580                 }
 581
 582                 /* we don't handle 5 byte sequences */
 583                 errno = EINVAL;
 584                 goto error;
 585         }
 586
 587         if (in_left > 0) {
 588                 errno = E2BIG;
 589                 goto error;
 590         }
 591
 592         *inbytesleft = in_left;
 593         *outbytesleft = out_left;
 594         *inbuf = (const char *)c;
 595         *outbuf = (char *)uc;
 596         return 0;
 597
 598 error:
 599         *inbytesleft = in_left;
 600         *outbytesleft = out_left;
 601         *inbuf = (const char *)c;
 602         *outbuf = (char *)uc;
 603         return -1;
 604 }
 605
 606
 607 /*
 608   this takes a UTF16 sequence and produces a UTF8 sequence
 609  */
 610 static size_t utf8_push(void *cd, const char **inbuf, size_t *inbytesleft,
 611                         char **outbuf, size_t *outbytesleft)
 612 {
 613         size_t in_left=*inbytesleft, out_left=*outbytesleft;
 614         uint8_t *c = (uint8_t *)*outbuf;
 615         const uint8_t *uc = (const uint8_t *)*inbuf;
 616
 617         while (in_left >= 2 && out_left >= 1) {
 618                 unsigned int codepoint;
 619
 620                 if (uc[1] == 0 && !(uc[0] & 0x80)) {
 621                         /* simplest case */
 622                         c[0] = uc[0];
 623                         in_left  -= 2;
 624                         out_left -= 1;
 625                         uc += 2;
 626                         c  += 1;
 627                         continue;
 628                 }
 629
 630                 if ((uc[1]&0xf8) == 0) {
 631                         /* next simplest case */
 632                         if (out_left < 2) {
 633                                 errno = E2BIG;
 634                                 goto error;
 635                         }
 636                         c[0] = 0xc0 | (uc[0]>>6) | (uc[1]<<2);
 637                         c[1] = 0x80 | (uc[0] & 0x3f);
 638                         in_left  -= 2;
 639                         out_left -= 2;
 640                         uc += 2;
 641                         c  += 2;
 642                         continue;
 643                 }
 644
 645                 if ((uc[1] & 0xfc) == 0xdc) {
 646                         /* its the second part of a 4 byte sequence. Illegal */
 647                         if (in_left < 4) {
 648                                 errno = EINVAL;
 649                         } else {
 650                                 errno = EILSEQ;
 651                         }
 652                         goto error;
 653                 }
 654
 655                 if ((uc[1] & 0xfc) != 0xd8) {
 656                         codepoint = uc[0] | (uc[1]<<8);
 657                         if (out_left < 3) {
 658                                 errno = E2BIG;
 659                                 goto error;
 660                         }
 661                         c[0] = 0xe0 | (codepoint >> 12);
 662                         c[1] = 0x80 | ((codepoint >> 6) & 0x3f);
 663                         c[2] = 0x80 | (codepoint & 0x3f);
 664
 665                         in_left  -= 2;
 666                         out_left -= 3;
 667                         uc  += 2;
 668                         c   += 3;
 669                         continue;
 670                 }
 671
 672                 /* its the first part of a 4 byte sequence */
 673                 if (in_left < 4) {
 674                         errno = EINVAL;
 675                         goto error;
 676                 }
 677                 if ((uc[3] & 0xfc) != 0xdc) {
 678                         errno = EILSEQ;
 679                         goto error;
 680                 }
 681                 codepoint = 0x10000 + (uc[2] | ((uc[3] & 0x3)<<8) |
 682                                        (uc[0]<<10) | ((uc[1] & 0x3)<<18));
 683
 684                 if (out_left < 4) {
 685                         errno = E2BIG;
 686                         goto error;
 687                 }
 688                 c[0] = 0xf0 | (codepoint >> 18);
 689                 c[1] = 0x80 | ((codepoint >> 12) & 0x3f);
 690                 c[2] = 0x80 | ((codepoint >> 6) & 0x3f);
 691                 c[3] = 0x80 | (codepoint & 0x3f);
 692
 693                 in_left  -= 4;
 694                 out_left -= 4;
 695                 uc       += 4;
 696                 c        += 4;
 697         }
 698
 699         if (in_left == 1) {
 700                 errno = EINVAL;
 701                 goto error;
 702         }
 703
 704         if (in_left > 1) {
 705                 errno = E2BIG;
 706                 goto error;
 707         }
 708
 709         *inbytesleft = in_left;
 710         *outbytesleft = out_left;
 711         *inbuf  = (const char *)uc;
 712         *outbuf = (char *)c;
 713
 714         return 0;
 715
 716 error:
 717         *inbytesleft = in_left;
 718         *outbytesleft = out_left;
 719         *inbuf  = (const char *)uc;
 720         *outbuf = (char *)c;
 721         return -1;
 722 }
 723
 724
 725 /*
 726   this takes a UTF16 munged sequence, modifies it according to the
 727   string2key rules, and produces a UTF16 sequence
 728
 729 The rules are:
 730
 731     1) any 0x0000 characters are mapped to 0x0001
 732
 733     2) convert any instance of 0xD800 - 0xDBFF (high surrogate)
 734        without an immediately following 0xDC00 - 0x0xDFFF (low surrogate) to
 735        U+FFFD (OBJECT REPLACEMENT CHARACTER).
 736
 737     3) the same for any low surrogate that was not preceded by a high surrogate.
 738
 739  */
 740 static size_t utf16_munged_pull(void *cd, const char **inbuf, size_t *inbytesleft,
 741                                char **outbuf, size_t *outbytesleft)
 742 {
 743         size_t in_left=*inbytesleft, out_left=*outbytesleft;
 744         uint8_t *c = (uint8_t *)*outbuf;
 745         const uint8_t *uc = (const uint8_t *)*inbuf;
 746
 747         while (in_left >= 2 && out_left >= 2) {
 748                 unsigned int codepoint = uc[0] | (uc[1]<<8);
 749
 750                 if (codepoint == 0) {
 751                         codepoint = 1;
 752                 }
 753
 754                 if ((codepoint & 0xfc00) == 0xd800) {
 755                         /* a high surrogate */
 756                         unsigned int codepoint2;
 757                         if (in_left < 4) {
 758                                 codepoint = 0xfffd;
 759                                 goto codepoint16;
 760                         }
 761                         codepoint2 = uc[2] | (uc[3]<<8);
 762                         if ((codepoint2 & 0xfc00) != 0xdc00) {
 763                                 /* high surrogate not followed by low
 764                                    surrogate: convert to 0xfffd */
 765                                 codepoint = 0xfffd;
 766                                 goto codepoint16;
 767                         }
 768                         if (out_left < 4) {
 769                                 errno = E2BIG;
 770                                 goto error;
 771                         }
 772                         memcpy(c, uc, 4);
 773                         in_left  -= 4;
 774                         out_left -= 4;
 775                         uc       += 4;
 776                         c        += 4;
 777                         continue;
 778                 }
 779
 780                 if ((codepoint & 0xfc00) == 0xdc00) {
 781                         /* low surrogate not preceded by high
 782                            surrogate: convert to 0xfffd */
 783                         codepoint = 0xfffd;
 784                 }
 785
 786         codepoint16:
 787                 c[0] = codepoint & 0xFF;
 788                 c[1] = (codepoint>>8) & 0xFF;
 789
 790                 in_left  -= 2;
 791                 out_left -= 2;
 792                 uc  += 2;
 793                 c   += 2;
 794                 continue;
 795         }
 796
 797         if (in_left == 1) {
 798                 errno = EINVAL;
 799                 goto error;
 800         }
 801
 802         if (in_left > 1) {
 803                 errno = E2BIG;
 804                 goto error;
 805         }
 806
 807         *inbytesleft = in_left;
 808         *outbytesleft = out_left;
 809         *inbuf  = (const char *)uc;
 810         *outbuf = (char *)c;
 811
 812         return 0;
 813
 814 error:
 815         *inbytesleft = in_left;
 816         *outbytesleft = out_left;
 817         *inbuf  = (const char *)uc;
 818         *outbuf = (char *)c;
 819         return -1;
 820 }
 821
 822
 823