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 #ifdef strcasecmp
  27 #undef strcasecmp
  28 #endif
  29
  30 #ifdef static_decl_charset
  31 static_decl_charset;
  32 #endif
  33
  34 /**
  35  * @file
  36  *
  37  * @brief Samba wrapper/stub for iconv character set conversion.
  38  *
  39  * iconv is the XPG2 interface for converting between character
  40  * encodings.  This file provides a Samba wrapper around it, and also
  41  * a simple reimplementation that is used if the system does not
  42  * implement iconv.
  43  *
  44  * Samba only works with encodings that are supersets of ASCII: ascii
  45  * characters like whitespace can be tested for directly, multibyte
  46  * sequences start with a byte with the high bit set, and strings are
  47  * terminated by a nul byte.
  48  *
  49  * Note that the only function provided by iconv is conversion between
  50  * characters.  It doesn't directly support operations like
  51  * uppercasing or comparison.  We have to convert to UTF-16LE and
  52  * compare there.
  53  *
  54  * @sa Samba Developers Guide
  55  **/
  56
  57 static size_t ascii_pull  (void *,const char **, size_t *, char **, size_t *);
  58 static size_t ascii_push  (void *,const char **, size_t *, char **, size_t *);
  59 static size_t latin1_push(void *,const char **, size_t *, char **, size_t *);
  60 static size_t utf8_pull   (void *,const char **, size_t *, char **, size_t *);
  61 static size_t utf8_push   (void *,const char **, size_t *, char **, size_t *);
  62 static size_t utf16_munged_pull(void *,const char **, size_t *, char **, size_t *);
  63 static size_t ucs2hex_pull(void *,const char **, size_t *, char **, size_t *);
  64 static size_t ucs2hex_push(void *,const char **, size_t *, char **, size_t *);
  65 static size_t iconv_copy  (void *,const char **, size_t *, char **, size_t *);
  66 static size_t iconv_swab  (void *,const char **, size_t *, char **, size_t *);
  67
  68 static const struct charset_functions builtin_functions[] = {
  69         /* windows is closest to UTF-16 */
  70         {"UCS-2LE",  iconv_copy, iconv_copy},
  71         {"UTF-16LE",  iconv_copy, iconv_copy},
  72         {"UCS-2BE",  iconv_swab, iconv_swab},
  73         {"UTF-16BE",  iconv_swab, iconv_swab},
  74
  75         /* we include the UTF-8 alias to cope with differing locale settings */
  76         {"UTF8",   utf8_pull,  utf8_push},
  77         {"UTF-8",   utf8_pull,  utf8_push},
  78
  79         /* this handles the munging needed for String2Key */
  80         {"UTF16_MUNGED",   utf16_munged_pull,  iconv_copy},
  81
  82         {"ASCII", ascii_pull, ascii_push},
  83         {"646", ascii_pull, ascii_push},
  84         {"ISO-8859-1", ascii_pull, latin1_push},
  85         {"UCS2-HEX", ucs2hex_pull, ucs2hex_push}
  86 };
  87
  88 static struct charset_functions *charsets = NULL;
  89
  90 static struct charset_functions *find_charset_functions(const char *name)
  91 {
  92         struct charset_functions *c;
  93
  94         /* Check whether we already have this charset... */
  95         for (c = charsets; c != NULL; c = c->next) {
  96                 if(strcasecmp(c->name, name) == 0) {
  97                         return c;
  98                 }
  99                 c = c->next;
 100         }
 101
 102         return NULL;
 103 }
 104
 105 bool smb_register_charset(const struct charset_functions *funcs_in)
 106 {
 107         struct charset_functions *funcs;
 108
 109         DEBUG(5, ("Attempting to register new charset %s\n", funcs_in->name));
 110         /* Check whether we already have this charset... */
 111         if (find_charset_functions(funcs_in->name)) {
 112                 DEBUG(0, ("Duplicate charset %s, not registering\n", funcs_in->name));
 113                 return false;
 114         }
 115
 116         funcs = talloc(NULL, struct charset_functions);
 117         if (!funcs) {
 118                 DEBUG(0, ("Out of memory duplicating charset %s\n", funcs_in->name));
 119                 return false;
 120         }
 121         *funcs = *funcs_in;
 122
 123         funcs->next = funcs->prev = NULL;
 124         DEBUG(5, ("Registered charset %s\n", funcs->name));
 125         DLIST_ADD(charsets, funcs);
 126         return true;
 127 }
 128
 129 static void lazy_initialize_iconv(void)
 130 {
 131 #ifdef static_init_charset
 132         static bool initialized = false;
 133
 134         if (!initialized) {
 135                 static_init_charset;
 136                 initialized = true;
 137         }
 138 #endif
 139 }
 140
 141 #ifdef HAVE_NATIVE_ICONV
 142 /* if there was an error then reset the internal state,
 143    this ensures that we don't have a shift state remaining for
 144    character sets like SJIS */
 145 static size_t sys_iconv(void *cd,
 146                         const char **inbuf, size_t *inbytesleft,
 147                         char **outbuf, size_t *outbytesleft)
 148 {
 149         size_t ret = iconv((iconv_t)cd,
 150                            discard_const_p(char *, inbuf), inbytesleft,
 151                            outbuf, outbytesleft);
 152         if (ret == (size_t)-1) iconv(cd, NULL, NULL, NULL, NULL);
 153         return ret;
 154 }
 155 #endif
 156
 157 /**
 158  * This is a simple portable iconv() implementaion.
 159  *
 160  * It only knows about a very small number of character sets - just
 161  * enough that Samba works on systems that don't have iconv.
 162  **/
 163 _PUBLIC_ size_t smb_iconv(smb_iconv_t cd,
 164                  const char **inbuf, size_t *inbytesleft,
 165                  char **outbuf, size_t *outbytesleft)
 166 {
 167         /* in many cases we can go direct */
 168         if (cd->direct) {
 169                 return cd->direct(cd->cd_direct,
 170                                   inbuf, inbytesleft, outbuf, outbytesleft);
 171         }
 172
 173         /* otherwise we have to do it chunks at a time */
 174         {
 175 #ifndef SMB_ICONV_BUFSIZE
 176 #define SMB_ICONV_BUFSIZE 2048
 177 #endif
 178                 TALLOC_CTX *mem_ctx;
 179                 size_t bufsize;
 180                 char *cvtbuf;
 181
 182 #if _SAMBA_BUILD_ == 3
 183                 mem_ctx = talloc_tos();
 184 #else
 185                 mem_ctx = cd;
 186 #endif
 187                 cvtbuf = talloc_array(mem_ctx, char, SMB_ICONV_BUFSIZE);
 188
 189                 if (!cvtbuf) {
 190                         return (size_t)-1;
 191                 }
 192
 193                 while (*inbytesleft > 0) {
 194                         char *bufp1 = cvtbuf;
 195                         const char *bufp2 = cvtbuf;
 196
 197                         bufsize = SMB_ICONV_BUFSIZE;
 198
 199                         if (cd->pull(cd->cd_pull,
 200                                      inbuf, inbytesleft, &bufp1, &bufsize) == -1
 201                             && errno != E2BIG) {
 202                                 talloc_free(cvtbuf);
 203                                 return -1;
 204                         }
 205
 206                         bufsize = SMB_ICONV_BUFSIZE - bufsize;
 207
 208                         if (cd->push(cd->cd_push,
 209                                      &bufp2, &bufsize,
 210                                      outbuf, outbytesleft) == -1) {
 211                                 talloc_free(cvtbuf);
 212                                 return -1;
 213                         }
 214                 }
 215                 talloc_free(cvtbuf);
 216         }
 217
 218         return 0;
 219 }
 220
 221 static bool is_utf16(const char *name)
 222 {
 223         return strcasecmp(name, "UCS-2LE") == 0 ||
 224                 strcasecmp(name, "UTF-16LE") == 0;
 225 }
 226
 227 static int smb_iconv_t_destructor(smb_iconv_t hwd)
 228 {
 229 #ifdef HAVE_NATIVE_ICONV
 230         if (hwd->cd_pull != NULL && hwd->cd_pull != (iconv_t)-1)
 231                 iconv_close(hwd->cd_pull);
 232         if (hwd->cd_push != NULL && hwd->cd_push != (iconv_t)-1)
 233                 iconv_close(hwd->cd_push);
 234         if (hwd->cd_direct != NULL && hwd->cd_direct != (iconv_t)-1)
 235                 iconv_close(hwd->cd_direct);
 236 #endif
 237
 238         return 0;
 239 }
 240
 241 _PUBLIC_ smb_iconv_t smb_iconv_open_ex(TALLOC_CTX *mem_ctx, const char *tocode,
 242                               const char *fromcode, bool native_iconv)
 243 {
 244         smb_iconv_t ret;
 245         const struct charset_functions *from=NULL, *to=NULL;
 246         int i;
 247
 248         lazy_initialize_iconv();
 249
 250         ret = (smb_iconv_t)talloc_named(mem_ctx,
 251                                         sizeof(*ret),
 252                                         "iconv(%s,%s)", tocode, fromcode);
 253         if (!ret) {
 254                 errno = ENOMEM;
 255                 return (smb_iconv_t)-1;
 256         }
 257         memset(ret, 0, sizeof(*ret));
 258         talloc_set_destructor(ret, smb_iconv_t_destructor);
 259
 260         /* check for the simplest null conversion */
 261         if (strcmp(fromcode, tocode) == 0) {
 262                 ret->direct = iconv_copy;
 263                 return ret;
 264         }
 265
 266         for (i=0;i<ARRAY_SIZE(builtin_functions);i++) {
 267                 if (strcasecmp(fromcode, builtin_functions[i].name) == 0) {
 268                         from = &builtin_functions[i];
 269                 }
 270                 if (strcasecmp(tocode, builtin_functions[i].name) == 0) {
 271                         to = &builtin_functions[i];
 272                 }
 273         }
 274
 275         if (from == NULL) {
 276                 for (from=charsets; from; from=from->next) {
 277                         if (strcasecmp(from->name, fromcode) == 0) break;
 278                 }
 279         }
 280
 281         if (to == NULL) {
 282                 for (to=charsets; to; to=to->next) {
 283                         if (strcasecmp(to->name, tocode) == 0) break;
 284                 }
 285         }
 286
 287 #ifdef HAVE_NATIVE_ICONV
 288         if ((!from || !to) && !native_iconv) {
 289                 goto failed;
 290         }
 291         if (!from) {
 292                 ret->pull = sys_iconv;
 293                 ret->cd_pull = iconv_open("UTF-16LE", fromcode);
 294                 if (ret->cd_pull == (iconv_t)-1)
 295                         ret->cd_pull = iconv_open("UCS-2LE", fromcode);
 296                 if (ret->cd_pull == (iconv_t)-1) goto failed;
 297         }
 298
 299         if (!to) {
 300                 ret->push = sys_iconv;
 301                 ret->cd_push = iconv_open(tocode, "UTF-16LE");
 302                 if (ret->cd_push == (iconv_t)-1)
 303                         ret->cd_push = iconv_open(tocode, "UCS-2LE");
 304                 if (ret->cd_push == (iconv_t)-1) goto failed;
 305         }
 306 #else
 307         if (!from || !to) {
 308                 goto failed;
 309         }
 310 #endif
 311
 312         /* check for conversion to/from ucs2 */
 313         if (is_utf16(fromcode) && to) {
 314                 ret->direct = to->push;
 315                 return ret;
 316         }
 317         if (is_utf16(tocode) && from) {
 318                 ret->direct = from->pull;
 319                 return ret;
 320         }
 321
 322 #ifdef HAVE_NATIVE_ICONV
 323         if (is_utf16(fromcode)) {
 324                 ret->direct = sys_iconv;
 325                 ret->cd_direct = ret->cd_push;
 326                 ret->cd_push = NULL;
 327                 return ret;
 328         }
 329         if (is_utf16(tocode)) {
 330                 ret->direct = sys_iconv;
 331                 ret->cd_direct = ret->cd_pull;
 332                 ret->cd_pull = NULL;
 333                 return ret;
 334         }
 335 #endif
 336
 337         /* the general case has to go via a buffer */
 338         if (!ret->pull) ret->pull = from->pull;
 339         if (!ret->push) ret->push = to->push;
 340         return ret;
 341
 342 failed:
 343         talloc_free(ret);
 344         errno = EINVAL;
 345         return (smb_iconv_t)-1;
 346 }
 347
 348 /*
 349   simple iconv_open() wrapper
 350  */
 351 _PUBLIC_ smb_iconv_t smb_iconv_open(const char *tocode, const char *fromcode)
 352 {
 353         return smb_iconv_open_ex(NULL, tocode, fromcode, true);
 354 }
 355
 356 /*
 357   simple iconv_close() wrapper
 358 */
 359 _PUBLIC_ int smb_iconv_close(smb_iconv_t cd)
 360 {
 361         talloc_free(cd);
 362         return 0;
 363 }
 364
 365
 366 /**********************************************************************
 367  the following functions implement the builtin character sets in Samba
 368  and also the "test" character sets that are designed to test
 369  multi-byte character set support for english users
 370 ***********************************************************************/
 371 static size_t ascii_pull(void *cd, const char **inbuf, size_t *inbytesleft,
 372                          char **outbuf, size_t *outbytesleft)
 373 {
 374         while (*inbytesleft >= 1 && *outbytesleft >= 2) {
 375                 (*outbuf)[0] = (*inbuf)[0];
 376                 (*outbuf)[1] = 0;
 377                 (*inbytesleft)  -= 1;
 378                 (*outbytesleft) -= 2;
 379                 (*inbuf)  += 1;
 380                 (*outbuf) += 2;
 381         }
 382
 383         if (*inbytesleft > 0) {
 384                 errno = E2BIG;
 385                 return -1;
 386         }
 387
 388         return 0;
 389 }
 390
 391 static size_t ascii_push(void *cd, const char **inbuf, size_t *inbytesleft,
 392                          char **outbuf, size_t *outbytesleft)
 393 {
 394         int ir_count=0;
 395
 396         while (*inbytesleft >= 2 && *outbytesleft >= 1) {
 397                 (*outbuf)[0] = (*inbuf)[0] & 0x7F;
 398                 if ((*inbuf)[1]) ir_count++;
 399                 (*inbytesleft)  -= 2;
 400                 (*outbytesleft) -= 1;
 401                 (*inbuf)  += 2;
 402                 (*outbuf) += 1;
 403         }
 404
 405         if (*inbytesleft == 1) {
 406                 errno = EINVAL;
 407                 return -1;
 408         }
 409
 410         if (*inbytesleft > 1) {
 411                 errno = E2BIG;
 412                 return -1;
 413         }
 414
 415         return ir_count;
 416 }
 417
 418 static size_t latin1_push(void *cd, const char **inbuf, size_t *inbytesleft,
 419                          char **outbuf, size_t *outbytesleft)
 420 {
 421         int ir_count=0;
 422
 423         while (*inbytesleft >= 2 && *outbytesleft >= 1) {
 424                 (*outbuf)[0] = (*inbuf)[0];
 425                 if ((*inbuf)[1]) ir_count++;
 426                 (*inbytesleft)  -= 2;
 427                 (*outbytesleft) -= 1;
 428                 (*inbuf)  += 2;
 429                 (*outbuf) += 1;
 430         }
 431
 432         if (*inbytesleft == 1) {
 433                 errno = EINVAL;
 434                 return -1;
 435         }
 436
 437         if (*inbytesleft > 1) {
 438                 errno = E2BIG;
 439                 return -1;
 440         }
 441
 442         return ir_count;
 443 }
 444
 445 static size_t ucs2hex_pull(void *cd, const char **inbuf, size_t *inbytesleft,
 446                          char **outbuf, size_t *outbytesleft)
 447 {
 448         while (*inbytesleft >= 1 && *outbytesleft >= 2) {
 449                 unsigned int v;
 450
 451                 if ((*inbuf)[0] != '@') {
 452                         /* seven bit ascii case */
 453                         (*outbuf)[0] = (*inbuf)[0];
 454                         (*outbuf)[1] = 0;
 455                         (*inbytesleft)  -= 1;
 456                         (*outbytesleft) -= 2;
 457                         (*inbuf)  += 1;
 458                         (*outbuf) += 2;
 459                         continue;
 460                 }
 461                 /* it's a hex character */
 462                 if (*inbytesleft < 5) {
 463                         errno = EINVAL;
 464                         return -1;
 465                 }
 466
 467                 if (sscanf(&(*inbuf)[1], "%04x", &v) != 1) {
 468                         errno = EILSEQ;
 469                         return -1;
 470                 }
 471
 472                 (*outbuf)[0] = v&0xff;
 473                 (*outbuf)[1] = v>>8;
 474                 (*inbytesleft)  -= 5;
 475                 (*outbytesleft) -= 2;
 476                 (*inbuf)  += 5;
 477                 (*outbuf) += 2;
 478         }
 479
 480         if (*inbytesleft > 0) {
 481                 errno = E2BIG;
 482                 return -1;
 483         }
 484
 485         return 0;
 486 }
 487
 488 static size_t ucs2hex_push(void *cd, const char **inbuf, size_t *inbytesleft,
 489                            char **outbuf, size_t *outbytesleft)
 490 {
 491         while (*inbytesleft >= 2 && *outbytesleft >= 1) {
 492                 char buf[6];
 493
 494                 if ((*inbuf)[1] == 0 &&
 495                     ((*inbuf)[0] & 0x80) == 0 &&
 496                     (*inbuf)[0] != '@') {
 497                         (*outbuf)[0] = (*inbuf)[0];
 498                         (*inbytesleft)  -= 2;
 499                         (*outbytesleft) -= 1;
 500                         (*inbuf)  += 2;
 501                         (*outbuf) += 1;
 502                         continue;
 503                 }
 504                 if (*outbytesleft < 5) {
 505                         errno = E2BIG;
 506                         return -1;
 507                 }
 508                 snprintf(buf, 6, "@%04x", SVAL(*inbuf, 0));
 509                 memcpy(*outbuf, buf, 5);
 510                 (*inbytesleft)  -= 2;
 511                 (*outbytesleft) -= 5;
 512                 (*inbuf)  += 2;
 513                 (*outbuf) += 5;
 514         }
 515
 516         if (*inbytesleft == 1) {
 517                 errno = EINVAL;
 518                 return -1;
 519         }
 520
 521         if (*inbytesleft > 1) {
 522                 errno = E2BIG;
 523                 return -1;
 524         }
 525
 526         return 0;
 527 }
 528
 529 static size_t iconv_swab(void *cd, const char **inbuf, size_t *inbytesleft,
 530                          char **outbuf, size_t *outbytesleft)
 531 {
 532         int n;
 533
 534         n = MIN(*inbytesleft, *outbytesleft);
 535
 536         swab(*inbuf, *outbuf, (n&~1));
 537         if (n&1) {
 538                 (*outbuf)[n-1] = 0;
 539         }
 540
 541         (*inbytesleft) -= n;
 542         (*outbytesleft) -= n;
 543         (*inbuf) += n;
 544         (*outbuf) += n;
 545
 546         if (*inbytesleft > 0) {
 547                 errno = E2BIG;
 548                 return -1;
 549         }
 550
 551         return 0;
 552 }
 553
 554
 555 static size_t iconv_copy(void *cd, const char **inbuf, size_t *inbytesleft,
 556                          char **outbuf, size_t *outbytesleft)
 557 {
 558         int n;
 559
 560         n = MIN(*inbytesleft, *outbytesleft);
 561
 562         memmove(*outbuf, *inbuf, n);
 563
 564         (*inbytesleft) -= n;
 565         (*outbytesleft) -= n;
 566         (*inbuf) += n;
 567         (*outbuf) += n;
 568
 569         if (*inbytesleft > 0) {
 570                 errno = E2BIG;
 571                 return -1;
 572         }
 573
 574         return 0;
 575 }
 576
 577 /*
 578   this takes a UTF8 sequence and produces a UTF16 sequence
 579  */
 580 static size_t utf8_pull(void *cd, const char **inbuf, size_t *inbytesleft,
 581                          char **outbuf, size_t *outbytesleft)
 582 {
 583         size_t in_left=*inbytesleft, out_left=*outbytesleft;
 584         const uint8_t *c = (const uint8_t *)*inbuf;
 585         uint8_t *uc = (uint8_t *)*outbuf;
 586
 587         while (in_left >= 1 && out_left >= 2) {
 588                 if ((c[0] & 0x80) == 0) {
 589                         uc[0] = c[0];
 590                         uc[1] = 0;
 591                         c  += 1;
 592                         in_left  -= 1;
 593                         out_left -= 2;
 594                         uc += 2;
 595                         continue;
 596                 }
 597
 598                 if ((c[0] & 0xe0) == 0xc0) {
 599                         if (in_left < 2 ||
 600                             (c[1] & 0xc0) != 0x80) {
 601                                 errno = EILSEQ;
 602                                 goto error;
 603                         }
 604                         uc[1] = (c[0]>>2) & 0x7;
 605                         uc[0] = (c[0]<<6) | (c[1]&0x3f);
 606                         c  += 2;
 607                         in_left  -= 2;
 608                         out_left -= 2;
 609                         uc += 2;
 610                         continue;
 611                 }
 612
 613                 if ((c[0] & 0xf0) == 0xe0) {
 614                         if (in_left < 3 ||
 615                             (c[1] & 0xc0) != 0x80 ||
 616                             (c[2] & 0xc0) != 0x80) {
 617                                 errno = EILSEQ;
 618                                 goto error;
 619                         }
 620                         uc[1] = ((c[0]&0xF)<<4) | ((c[1]>>2)&0xF);
 621                         uc[0] = (c[1]<<6) | (c[2]&0x3f);
 622                         c  += 3;
 623                         in_left  -= 3;
 624                         out_left -= 2;
 625                         uc += 2;
 626                         continue;
 627                 }
 628
 629                 if ((c[0] & 0xf8) == 0xf0) {
 630                         unsigned int codepoint;
 631                         if (in_left < 4 ||
 632                             (c[1] & 0xc0) != 0x80 ||
 633                             (c[2] & 0xc0) != 0x80 ||
 634                             (c[3] & 0xc0) != 0x80) {
 635                                 errno = EILSEQ;
 636                                 goto error;
 637                         }
 638                         codepoint =
 639                                 (c[3]&0x3f) |
 640                                 ((c[2]&0x3f)<<6) |
 641                                 ((c[1]&0x3f)<<12) |
 642                                 ((c[0]&0x7)<<18);
 643                         if (codepoint < 0x10000) {
 644                                 /* accept UTF-8 characters that are not
 645                                    minimally packed, but pack the result */
 646                                 uc[0] = (codepoint & 0xFF);
 647                                 uc[1] = (codepoint >> 8);
 648                                 c += 4;
 649                                 in_left -= 4;
 650                                 out_left -= 2;
 651                                 uc += 2;
 652                                 continue;
 653                         }
 654
 655                         codepoint -= 0x10000;
 656
 657                         if (out_left < 4) {
 658                                 errno = E2BIG;
 659                                 goto error;
 660                         }
 661
 662                         uc[0] = (codepoint>>10) & 0xFF;
 663                         uc[1] = (codepoint>>18) | 0xd8;
 664                         uc[2] = codepoint & 0xFF;
 665                         uc[3] = ((codepoint>>8) & 0x3) | 0xdc;
 666                         c  += 4;
 667                         in_left  -= 4;
 668                         out_left -= 4;
 669                         uc += 4;
 670                         continue;
 671                 }
 672
 673                 /* we don't handle 5 byte sequences */
 674                 errno = EINVAL;
 675                 goto error;
 676         }
 677
 678         if (in_left > 0) {
 679                 errno = E2BIG;
 680                 goto error;
 681         }
 682
 683         *inbytesleft = in_left;
 684         *outbytesleft = out_left;
 685         *inbuf = (const char *)c;
 686         *outbuf = (char *)uc;
 687         return 0;
 688
 689 error:
 690         *inbytesleft = in_left;
 691         *outbytesleft = out_left;
 692         *inbuf = (const char *)c;
 693         *outbuf = (char *)uc;
 694         return -1;
 695 }
 696
 697
 698 /*
 699   this takes a UTF16 sequence and produces a UTF8 sequence
 700  */
 701 static size_t utf8_push(void *cd, const char **inbuf, size_t *inbytesleft,
 702                         char **outbuf, size_t *outbytesleft)
 703 {
 704         size_t in_left=*inbytesleft, out_left=*outbytesleft;
 705         uint8_t *c = (uint8_t *)*outbuf;
 706         const uint8_t *uc = (const uint8_t *)*inbuf;
 707
 708         while (in_left >= 2 && out_left >= 1) {
 709                 unsigned int codepoint;
 710
 711                 if (uc[1] == 0 && !(uc[0] & 0x80)) {
 712                         /* simplest case */
 713                         c[0] = uc[0];
 714                         in_left  -= 2;
 715                         out_left -= 1;
 716                         uc += 2;
 717                         c  += 1;
 718                         continue;
 719                 }
 720
 721                 if ((uc[1]&0xf8) == 0) {
 722                         /* next simplest case */
 723                         if (out_left < 2) {
 724                                 errno = E2BIG;
 725                                 goto error;
 726                         }
 727                         c[0] = 0xc0 | (uc[0]>>6) | (uc[1]<<2);
 728                         c[1] = 0x80 | (uc[0] & 0x3f);
 729                         in_left  -= 2;
 730                         out_left -= 2;
 731                         uc += 2;
 732                         c  += 2;
 733                         continue;
 734                 }
 735
 736                 if ((uc[1] & 0xfc) == 0xdc) {
 737                         /* its the second part of a 4 byte sequence. Illegal */
 738                         if (in_left < 4) {
 739                                 errno = EINVAL;
 740                         } else {
 741                                 errno = EILSEQ;
 742                         }
 743                         goto error;
 744                 }
 745
 746                 if ((uc[1] & 0xfc) != 0xd8) {
 747                         codepoint = uc[0] | (uc[1]<<8);
 748                         if (out_left < 3) {
 749                                 errno = E2BIG;
 750                                 goto error;
 751                         }
 752                         c[0] = 0xe0 | (codepoint >> 12);
 753                         c[1] = 0x80 | ((codepoint >> 6) & 0x3f);
 754                         c[2] = 0x80 | (codepoint & 0x3f);
 755
 756                         in_left  -= 2;
 757                         out_left -= 3;
 758                         uc  += 2;
 759                         c   += 3;
 760                         continue;
 761                 }
 762
 763                 /* its the first part of a 4 byte sequence */
 764                 if (in_left < 4) {
 765                         errno = EINVAL;
 766                         goto error;
 767                 }
 768                 if ((uc[3] & 0xfc) != 0xdc) {
 769                         errno = EILSEQ;
 770                         goto error;
 771                 }
 772                 codepoint = 0x10000 + (uc[2] | ((uc[3] & 0x3)<<8) |
 773                                        (uc[0]<<10) | ((uc[1] & 0x3)<<18));
 774
 775                 if (out_left < 4) {
 776                         errno = E2BIG;
 777                         goto error;
 778                 }
 779                 c[0] = 0xf0 | (codepoint >> 18);
 780                 c[1] = 0x80 | ((codepoint >> 12) & 0x3f);
 781                 c[2] = 0x80 | ((codepoint >> 6) & 0x3f);
 782                 c[3] = 0x80 | (codepoint & 0x3f);
 783
 784                 in_left  -= 4;
 785                 out_left -= 4;
 786                 uc       += 4;
 787                 c        += 4;
 788         }
 789
 790         if (in_left == 1) {
 791                 errno = EINVAL;
 792                 goto error;
 793         }
 794
 795         if (in_left > 1) {
 796                 errno = E2BIG;
 797                 goto error;
 798         }
 799
 800         *inbytesleft = in_left;
 801         *outbytesleft = out_left;
 802         *inbuf  = (const char *)uc;
 803         *outbuf = (char *)c;
 804
 805         return 0;
 806
 807 error:
 808         *inbytesleft = in_left;
 809         *outbytesleft = out_left;
 810         *inbuf  = (const char *)uc;
 811         *outbuf = (char *)c;
 812         return -1;
 813 }
 814
 815
 816 /*
 817   this takes a UTF16 munged sequence, modifies it according to the
 818   string2key rules, and produces a UTF16 sequence
 819
 820 The rules are:
 821
 822     1) any 0x0000 characters are mapped to 0x0001
 823
 824     2) convert any instance of 0xD800 - 0xDBFF (high surrogate)
 825        without an immediately following 0xDC00 - 0x0xDFFF (low surrogate) to
 826        U+FFFD (OBJECT REPLACEMENT CHARACTER).
 827
 828     3) the same for any low surrogate that was not preceded by a high surrogate.
 829
 830  */
 831 static size_t utf16_munged_pull(void *cd, const char **inbuf, size_t *inbytesleft,
 832                                char **outbuf, size_t *outbytesleft)
 833 {
 834         size_t in_left=*inbytesleft, out_left=*outbytesleft;
 835         uint8_t *c = (uint8_t *)*outbuf;
 836         const uint8_t *uc = (const uint8_t *)*inbuf;
 837
 838         while (in_left >= 2 && out_left >= 2) {
 839                 unsigned int codepoint = uc[0] | (uc[1]<<8);
 840
 841                 if (codepoint == 0) {
 842                         codepoint = 1;
 843                 }
 844
 845                 if ((codepoint & 0xfc00) == 0xd800) {
 846                         /* a high surrogate */
 847                         unsigned int codepoint2;
 848                         if (in_left < 4) {
 849                                 codepoint = 0xfffd;
 850                                 goto codepoint16;
 851                         }
 852                         codepoint2 = uc[2] | (uc[3]<<8);
 853                         if ((codepoint2 & 0xfc00) != 0xdc00) {
 854                                 /* high surrogate not followed by low
 855                                    surrogate: convert to 0xfffd */
 856                                 codepoint = 0xfffd;
 857                                 goto codepoint16;
 858                         }
 859                         if (out_left < 4) {
 860                                 errno = E2BIG;
 861                                 goto error;
 862                         }
 863                         memcpy(c, uc, 4);
 864                         in_left  -= 4;
 865                         out_left -= 4;
 866                         uc       += 4;
 867                         c        += 4;
 868                         continue;
 869                 }
 870
 871                 if ((codepoint & 0xfc00) == 0xdc00) {
 872                         /* low surrogate not preceded by high
 873                            surrogate: convert to 0xfffd */
 874                         codepoint = 0xfffd;
 875                 }
 876
 877         codepoint16:
 878                 c[0] = codepoint & 0xFF;
 879                 c[1] = (codepoint>>8) & 0xFF;
 880
 881                 in_left  -= 2;
 882                 out_left -= 2;
 883                 uc  += 2;
 884                 c   += 2;
 885                 continue;
 886         }
 887
 888         if (in_left == 1) {
 889                 errno = EINVAL;
 890                 goto error;
 891         }
 892
 893         if (in_left > 1) {
 894                 errno = E2BIG;
 895                 goto error;
 896         }
 897
 898         *inbytesleft = in_left;
 899         *outbytesleft = out_left;
 900         *inbuf  = (const char *)uc;
 901         *outbuf = (char *)c;
 902
 903         return 0;
 904
 905 error:
 906         *inbytesleft = in_left;
 907         *outbytesleft = out_left;
 908         *inbuf  = (const char *)uc;
 909         *outbuf = (char *)c;
 910         return -1;
 911 }
 912
 913
 914