iconvdata/utf-7.c

   1 /* Conversion module for UTF-7.
   2    Copyright (C) 2000 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Bruno Haible <haible@clisp.cons.org>, 2000.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 /* UTF-7 is a legacy encoding used for transmitting Unicode within the
  22    ASCII character set, used primarily by mail agents.  New programs
  23    are encouraged to use UTF-8 instead.
  24
  25    UTF-7 is specified in RFC 2152 (and old RFC 1641, RFC 1642).  The
  26    original Base64 encoding is defined in RFC 2045.  */
  27
  28 #include <dlfcn.h>
  29 #include <gconv.h>
  30 #include <stdint.h>
  31 #include <stdlib.h>
  32
  33
  34 /* Define this to 1 if you want the so-called "optional direct" characters
  35       ! " # $ % & * ; < = > @ [ ] ^ _ ` { | }
  36    to be encoded. Define to 0 if you want them to be passed straight
  37    through, like the so-called "direct" characters.
  38    We set this to 1 because it's safer.
  39  */
  40 #define UTF7_ENCODE_OPTIONAL_CHARS 1
  41
  42
  43 /* The set of "direct characters":
  44    A-Z a-z 0-9 ' ( ) , - . / : ? space tab lf cr
  45 */
  46
  47 static const unsigned char direct_tab[128/8] =
  48   {
  49     0x00, 0x26, 0x00, 0x00, 0x81, 0xf3, 0xff, 0x87,
  50     0xfe, 0xff, 0xff, 0x07, 0xfe, 0xff, 0xff, 0x07
  51   };
  52
  53 static inline int
  54 isdirect (uint32_t ch)
  55 {
  56   return (ch < 128 && ((direct_tab[ch >> 3] >> (ch & 7)) & 1));
  57 }
  58
  59
  60 /* The set of "direct and optional direct characters":
  61    A-Z a-z 0-9 ' ( ) , - . / : ? space tab lf cr
  62    ! " # $ % & * ; < = > @ [ ] ^ _ ` { | }
  63 */
  64
  65 static const unsigned char xdirect_tab[128/8] =
  66   {
  67     0x00, 0x26, 0x00, 0x00, 0xff, 0xf7, 0xff, 0xff,
  68     0xff, 0xff, 0xff, 0xef, 0xff, 0xff, 0xff, 0x3f
  69   };
  70
  71 static inline int
  72 isxdirect (uint32_t ch)
  73 {
  74   return (ch < 128 && ((xdirect_tab[ch >> 3] >> (ch & 7)) & 1));
  75 }
  76
  77
  78 /* The set of "extended base64 characters":
  79    A-Z a-z 0-9 + / -
  80 */
  81
  82 static const unsigned char xbase64_tab[128/8] =
  83   {
  84     0x00, 0x00, 0x00, 0x00, 0x00, 0xa8, 0xff, 0x03,
  85     0xfe, 0xff, 0xff, 0x07, 0xfe, 0xff, 0xff, 0x07
  86   };
  87
  88 static inline int
  89 isxbase64 (uint32_t ch)
  90 {
  91   return (ch < 128 && ((xbase64_tab[ch >> 3] >> (ch & 7)) & 1));
  92 }
  93
  94
  95 /* Converts a value in the range 0..63 to a base64 encoded char.  */
  96 static inline unsigned char
  97 base64 (unsigned int i)
  98 {
  99   if (i < 26)
 100     return i + 'A';
 101   else if (i < 52)
 102     return i - 26 + 'a';
 103   else if (i < 62)
 104     return i - 52 + '0';
 105   else if (i == 62)
 106     return '+';
 107   else if (i == 63)
 108     return '/';
 109   else
 110     abort ();
 111 }
 112
 113
 114 /* Definitions used in the body of the `gconv' function.  */
 115 #define CHARSET_NAME            "UTF-7//"
 116 #define DEFINE_INIT             1
 117 #define DEFINE_FINI             1
 118 #define FROM_LOOP               from_utf7_loop
 119 #define TO_LOOP                 to_utf7_loop
 120 #define MIN_NEEDED_FROM         1
 121 #define MAX_NEEDED_FROM         6
 122 #define MIN_NEEDED_TO           4
 123 #define MAX_NEEDED_TO           4
 124 #define PREPARE_LOOP \
 125   mbstate_t saved_state;                                                      \
 126   mbstate_t *statep = data->__statep;
 127 #define EXTRA_LOOP_ARGS         , statep
 128
 129
 130 /* Since we might have to reset input pointer we must be able to save
 131    and restore the state.  */
 132 #define SAVE_RESET_STATE(Save) \
 133   if (Save)                                                                   \
 134     saved_state = *statep;                                                    \
 135   else                                                                        \
 136     *statep = saved_state
 137
 138
 139 /* First define the conversion function from UTF-7 to UCS4.
 140    The state is structured as follows:
 141      __count bit 2..0: zero
 142      __count bit 8..3: shift
 143      __wch: data
 144    Precise meaning:
 145      shift      data
 146        0         --          not inside base64 encoding
 147      1..32  XX..XX00..00     inside base64, (32 - shift) bits pending
 148    This state layout is simpler than relying on STORE_REST/UNPACK_BYTES.
 149
 150    When shift = 0, __wch needs to store at most one lookahead byte (see
 151    __GCONV_INCOMPLETE_INPUT below).
 152 */
 153 #define MIN_NEEDED_INPUT        MIN_NEEDED_FROM
 154 #define MAX_NEEDED_INPUT        MAX_NEEDED_FROM
 155 #define MIN_NEEDED_OUTPUT       MIN_NEEDED_TO
 156 #define MAX_NEEDED_OUTPUT       MAX_NEEDED_TO
 157 #define LOOPFCT                 FROM_LOOP
 158 #define BODY \
 159   {                                                                           \
 160     uint_fast8_t ch = *inptr;                                                 \
 161                                                                               \
 162     if ((statep->__count >> 3) == 0)                                          \
 163       {                                                                       \
 164         /* base64 encoding inactive.  */                                      \
 165         if (isxdirect (ch))                                                   \
 166           {                                                                   \
 167             inptr++;                                                          \
 168             put32 (outptr, ch);                                               \
 169             outptr += 4;                                                      \
 170           }                                                                   \
 171         else if (__builtin_expect (ch == '+', 1))                             \
 172           {                                                                   \
 173             if (__builtin_expect (inptr + 2 >= inend, 0))                     \
 174               {                                                               \
 175                 /* Not enough input available.  */                            \
 176                 result = __GCONV_INCOMPLETE_INPUT;                            \
 177                 break;                                                        \
 178               }                                                               \
 179             if (inptr[1] == '-')                                              \
 180               {                                                               \
 181                 inptr += 2;                                                   \
 182                 put32 (outptr, ch);                                           \
 183                 outptr += 4;                                                  \
 184               }                                                               \
 185             else                                                              \
 186               {                                                               \
 187                 /* Switch into base64 mode.  */                               \
 188                 inptr++;                                                      \
 189                 statep->__count = (32 << 3);                                  \
 190                 statep->__value.__wch = 0;                                    \
 191               }                                                               \
 192           }                                                                   \
 193         else                                                                  \
 194           {                                                                   \
 195             /* The input is invalid.  */                                      \
 196             if (! ignore_errors_p ())                                         \
 197               {                                                               \
 198                 result = __GCONV_ILLEGAL_INPUT;                               \
 199                 break;                                                        \
 200               }                                                               \
 201                                                                               \
 202             ++inptr;                                                          \
 203             ++*irreversible;                                                  \
 204           }                                                                   \
 205       }                                                                       \
 206     else                                                                      \
 207       {                                                                       \
 208         /* base64 encoding active.  */                                        \
 209         uint32_t i;                                                           \
 210         int shift;                                                            \
 211                                                                               \
 212         if (ch >= 'A' && ch <= 'Z')                                           \
 213           i = ch - 'A';                                                       \
 214         else if (ch >= 'a' && ch <= 'z')                                      \
 215           i = ch - 'a' + 26;                                                  \
 216         else if (ch >= '0' && ch <= '9')                                      \
 217           i = ch - '0' + 52;                                                  \
 218         else if (ch == '+')                                                   \
 219           i = 62;                                                             \
 220         else if (ch == '/')                                                   \
 221           i = 63;                                                             \
 222         else                                                                  \
 223           {                                                                   \
 224             /* Terminate base64 encoding.  */                                 \
 225                                                                               \
 226             /* If accumulated data is nonzero, the input is invalid.  */      \
 227             /* Also, partial UTF-16 characters are invalid.  */               \
 228             if (__builtin_expect (statep->__value.__wch != 0, 0)              \
 229                 || __builtin_expect ((statep->__count >> 3) <= 26, 0))        \
 230               {                                                               \
 231                 if (! ignore_errors_p ())                                     \
 232                   {                                                           \
 233                     result = __GCONV_ILLEGAL_INPUT;                           \
 234                     break;                                                    \
 235                   }                                                           \
 236                                                                               \
 237                 ++inptr;                                                      \
 238                 ++*irreversible;                                              \
 239                 statep->__count = 0;                                          \
 240                 continue;                                                     \
 241               }                                                               \
 242                                                                               \
 243             if (ch == '-')                                                    \
 244               inptr++;                                                        \
 245                                                                               \
 246             statep->__count = 0;                                              \
 247             continue;                                                         \
 248           }                                                                   \
 249                                                                               \
 250         /* Concatenate the base64 integer i to the accumulator.  */           \
 251         shift = (statep->__count >> 3);                                       \
 252         if (shift > 6)                                                        \
 253           {                                                                   \
 254             uint32_t wch;                                                     \
 255                                                                               \
 256             shift -= 6;                                                       \
 257             wch = statep->__value.__wch | (i << shift);                       \
 258                                                                               \
 259             if (shift <= 16 && shift > 10)                                    \
 260               {                                                               \
 261                 /* An UTF-16 character has just been completed.  */           \
 262                 uint32_t wc1 = wch >> 16;                                     \
 263                                                                               \
 264                 /* UTF-16: When we see a High Surrogate, we must also decode  \
 265                    the following Low Surrogate. */                            \
 266                 if (!(wc1 >= 0xd800 && wc1 < 0xdc00))                         \
 267                   {                                                           \
 268                     wch = wch << 16;                                          \
 269                     shift += 16;                                              \
 270                     put32 (outptr, wc1);                                      \
 271                     outptr += 4;                                              \
 272                   }                                                           \
 273               }                                                               \
 274             else if (shift <= 10 && shift > 4)                                \
 275               {                                                               \
 276                 /* After a High Surrogate, verify that the next 16 bit        \
 277                    indeed form a Low Surrogate.  */                           \
 278                 uint32_t wc2 = wch & 0xffff;                                  \
 279                                                                               \
 280                 if (! __builtin_expect (wc2 >= 0xdc00 && wc2 < 0xe000, 1))    \
 281                   {                                                           \
 282                     if (! ignore_errors_p ())                                 \
 283                       {                                                       \
 284                         result = __GCONV_ILLEGAL_INPUT;                       \
 285                         break;                                                \
 286                       }                                                       \
 287                                                                               \
 288                     ++inptr;                                                  \
 289                     ++*irreversible;                                          \
 290                     statep->__count = 0;                                      \
 291                     continue;                                                 \
 292                   }                                                           \
 293               }                                                               \
 294                                                                               \
 295             statep->__value.__wch = wch;                                      \
 296           }                                                                   \
 297         else                                                                  \
 298           {                                                                   \
 299             /* An UTF-16 surrogate pair has just been completed.  */          \
 300             uint32_t wc1 = (uint32_t) statep->__value.__wch >> 16;            \
 301             uint32_t wc2 = ((uint32_t) statep->__value.__wch & 0xffff)        \
 302                            | (i >> (6 - shift));                              \
 303                                                                               \
 304             statep->__value.__wch = (i << shift) << 26;                       \
 305             shift += 26;                                                      \
 306                                                                               \
 307             assert (wc1 >= 0xd800 && wc1 < 0xdc00);                           \
 308             assert (wc2 >= 0xdc00 && wc2 < 0xe000);                           \
 309             put32 (outptr,                                                    \
 310                    0x10000 + ((wc1 - 0xd800) << 10) + (wc2 - 0xdc00));        \
 311             outptr += 4;                                                      \
 312           }                                                                   \
 313                                                                               \
 314         statep->__count = shift << 3;                                         \
 315                                                                               \
 316         /* Now that we digested the input increment the input pointer.  */    \
 317         inptr++;                                                              \
 318       }                                                                       \
 319   }
 320 #define LOOP_NEED_FLAGS
 321 #define EXTRA_LOOP_DECLS        , mbstate_t *statep
 322 #include <iconv/loop.c>
 323
 324
 325 /* Next, define the conversion from UCS4 to UTF-7.
 326    The state is structured as follows:
 327      __count bit 2..0: zero
 328      __count bit 4..3: shift
 329      __count bit 8..5: data
 330    Precise meaning:
 331      shift      data
 332        0         0           not inside base64 encoding
 333        1         0           inside base64, no pending bits
 334        2       XX00          inside base64, 2 bits known for next byte
 335        3       XXXX          inside base64, 4 bits known for next byte
 336
 337    __count bit 2..0 and __wch are always zero, because this direction
 338    never returns __GCONV_INCOMPLETE_INPUT.
 339 */
 340 #define MIN_NEEDED_INPUT        MIN_NEEDED_TO
 341 #define MAX_NEEDED_INPUT        MAX_NEEDED_TO
 342 #define MIN_NEEDED_OUTPUT       MIN_NEEDED_FROM
 343 #define MAX_NEEDED_OUTPUT       MAX_NEEDED_FROM
 344 #define LOOPFCT                 TO_LOOP
 345 #define BODY \
 346   {                                                                           \
 347     uint32_t ch = get32 (inptr);                                              \
 348                                                                               \
 349     if ((statep->__count & 0x18) == 0)                                        \
 350       {                                                                       \
 351         /* base64 encoding inactive */                                        \
 352         if (UTF7_ENCODE_OPTIONAL_CHARS ? isdirect (ch) : isxdirect (ch))      \
 353           {                                                                   \
 354             *outptr++ = (unsigned char) ch;                                   \
 355           }                                                                   \
 356         else                                                                  \
 357           {                                                                   \
 358             size_t count;                                                     \
 359                                                                               \
 360             if (ch == '+')                                                    \
 361               count = 2;                                                      \
 362             else if (ch < 0x10000)                                            \
 363               count = 3;                                                      \
 364             else if (ch < 0x110000)                                           \
 365               count = 6;                                                      \
 366             else                                                              \
 367               STANDARD_ERR_HANDLER (4);                                       \
 368                                                                               \
 369             if (__builtin_expect (outptr + count > outend, 0))                \
 370               {                                                               \
 371                 result = __GCONV_FULL_OUTPUT;                                 \
 372                 break;                                                        \
 373               }                                                               \
 374                                                                               \
 375             *outptr++ = '+';                                                  \
 376             if (ch == '+')                                                    \
 377               *outptr++ = '-';                                                \
 378             else if (ch < 0x10000)                                            \
 379               {                                                               \
 380                 *outptr++ = base64 (ch >> 10);                                \
 381                 *outptr++ = base64 ((ch >> 4) & 0x3f);                        \
 382                 statep->__count = ((ch & 15) << 5) | (3 << 3);                \
 383               }                                                               \
 384             else if (ch < 0x110000)                                           \
 385               {                                                               \
 386                 uint32_t ch1 = 0xd800 + ((ch - 0x10000) >> 10);               \
 387                 uint32_t ch2 = 0xdc00 + ((ch - 0x10000) & 0x3ff);             \
 388                                                                               \
 389                 ch = (ch1 << 16) | ch2;                                       \
 390                 *outptr++ = base64 (ch >> 26);                                \
 391                 *outptr++ = base64 ((ch >> 20) & 0x3f);                       \
 392                 *outptr++ = base64 ((ch >> 14) & 0x3f);                       \
 393                 *outptr++ = base64 ((ch >> 8) & 0x3f);                        \
 394                 *outptr++ = base64 ((ch >> 2) & 0x3f);                        \
 395                 statep->__count = ((ch & 3) << 7) | (2 << 3);                 \
 396               }                                                               \
 397             else                                                              \
 398               abort ();                                                       \
 399           }                                                                   \
 400       }                                                                       \
 401     else                                                                      \
 402       {                                                                       \
 403         /* base64 encoding active */                                          \
 404         if (UTF7_ENCODE_OPTIONAL_CHARS ? isdirect (ch) : isxdirect (ch))      \
 405           {                                                                   \
 406             /* deactivate base64 encoding */                                  \
 407             size_t count;                                                     \
 408                                                                               \
 409             count = ((statep->__count & 0x18) >= 0x10) + isxbase64 (ch) + 1;  \
 410             if (__builtin_expect (outptr + count > outend, 0))                \
 411               {                                                               \
 412                 result = __GCONV_FULL_OUTPUT;                                 \
 413                 break;                                                        \
 414               }                                                               \
 415                                                                               \
 416             if ((statep->__count & 0x18) >= 0x10)                             \
 417               *outptr++ = base64 ((statep->__count >> 3) & ~3);               \
 418             if (isxbase64 (ch))                                               \
 419               *outptr++ = '-';                                                \
 420             *outptr++ = (unsigned char) ch;                                   \
 421             statep->__count = 0;                                              \
 422           }                                                                   \
 423         else                                                                  \
 424           {                                                                   \
 425             size_t count;                                                     \
 426                                                                               \
 427             if (ch < 0x10000)                                                 \
 428               count = ((statep->__count & 0x18) >= 0x10 ? 3 : 2);             \
 429             else if (ch < 0x110000)                                           \
 430               count = ((statep->__count & 0x18) >= 0x18 ? 6 : 5);             \
 431             else                                                              \
 432               STANDARD_ERR_HANDLER (4);                                       \
 433                                                                               \
 434             if (__builtin_expect (outptr + count > outend, 0))                \
 435               {                                                               \
 436                 result = __GCONV_FULL_OUTPUT;                                 \
 437                 break;                                                        \
 438               }                                                               \
 439                                                                               \
 440             if (ch < 0x10000)                                                 \
 441               {                                                               \
 442                 switch ((statep->__count >> 3) & 3)                           \
 443                   {                                                           \
 444                   case 1:                                                     \
 445                     *outptr++ = base64 (ch >> 10);                            \
 446                     *outptr++ = base64 ((ch >> 4) & 0x3f);                    \
 447                     statep->__count = ((ch & 15) << 5) | (3 << 3);            \
 448                     break;                                                    \
 449                   case 2:                                                     \
 450                     *outptr++ =                                               \
 451                       base64 (((statep->__count >> 3) & ~3) | (ch >> 12));    \
 452                     *outptr++ = base64 ((ch >> 6) & 0x3f);                    \
 453                     *outptr++ = base64 (ch & 0x3f);                           \
 454                     statep->__count = (1 << 3);                               \
 455                     break;                                                    \
 456                   case 3:                                                     \
 457                     *outptr++ =                                               \
 458                       base64 (((statep->__count >> 3) & ~3) | (ch >> 14));    \
 459                     *outptr++ = base64 ((ch >> 8) & 0x3f);                    \
 460                     *outptr++ = base64 ((ch >> 2) & 0x3f);                    \
 461                     statep->__count = ((ch & 3) << 7) | (2 << 3);             \
 462                     break;                                                    \
 463                   default:                                                    \
 464                     abort ();                                                 \
 465                   }                                                           \
 466               }                                                               \
 467             else if (ch < 0x110000)                                           \
 468               {                                                               \
 469                 uint32_t ch1 = 0xd800 + ((ch - 0x10000) >> 10);               \
 470                 uint32_t ch2 = 0xdc00 + ((ch - 0x10000) & 0x3ff);             \
 471                                                                               \
 472                 ch = (ch1 << 16) | ch2;                                       \
 473                 switch ((statep->__count >> 3) & 3)                           \
 474                   {                                                           \
 475                   case 1:                                                     \
 476                     *outptr++ = base64 (ch >> 26);                            \
 477                     *outptr++ = base64 ((ch >> 20) & 0x3f);                   \
 478                     *outptr++ = base64 ((ch >> 14) & 0x3f);                   \
 479                     *outptr++ = base64 ((ch >> 8) & 0x3f);                    \
 480                     *outptr++ = base64 ((ch >> 2) & 0x3f);                    \
 481                     statep->__count = ((ch & 3) << 7) | (2 << 3);             \
 482                     break;                                                    \
 483                   case 2:                                                     \
 484                     *outptr++ =                                               \
 485                       base64 (((statep->__count >> 3) & ~3) | (ch >> 28));    \
 486                     *outptr++ = base64 ((ch >> 22) & 0x3f);                   \
 487                     *outptr++ = base64 ((ch >> 16) & 0x3f);                   \
 488                     *outptr++ = base64 ((ch >> 10) & 0x3f);                   \
 489                     *outptr++ = base64 ((ch >> 4) & 0x3f);                    \
 490                     statep->__count = ((ch & 15) << 5) | (3 << 3);            \
 491                     break;                                                    \
 492                   case 3:                                                     \
 493                     *outptr++ =                                               \
 494                       base64 (((statep->__count >> 3) & ~3) | (ch >> 30));    \
 495                     *outptr++ = base64 ((ch >> 24) & 0x3f);                   \
 496                     *outptr++ = base64 ((ch >> 18) & 0x3f);                   \
 497                     *outptr++ = base64 ((ch >> 12) & 0x3f);                   \
 498                     *outptr++ = base64 ((ch >> 6) & 0x3f);                    \
 499                     *outptr++ = base64 (ch & 0x3f);                           \
 500                     statep->__count = (1 << 3);                               \
 501                     break;                                                    \
 502                   default:                                                    \
 503                     abort ();                                                 \
 504                   }                                                           \
 505               }                                                               \
 506             else                                                              \
 507               abort ();                                                       \
 508           }                                                                   \
 509       }                                                                       \
 510                                                                               \
 511     /* Now that we wrote the output increment the input pointer.  */          \
 512     inptr += 4;                                                               \
 513   }
 514 #define LOOP_NEED_FLAGS
 515 #define EXTRA_LOOP_DECLS        , mbstate_t *statep
 516 #include <iconv/loop.c>
 517
 518
 519 /* Since this is a stateful encoding we have to provide code which resets
 520    the output state to the initial state.  This has to be done during the
 521    flushing.  */
 522 #define EMIT_SHIFT_TO_INIT \
 523   if (FROM_DIRECTION)                                                         \
 524     /* Nothing to emit.  */                                                   \
 525     memset (data->__statep, '\0', sizeof (mbstate_t));                        \
 526   else                                                                        \
 527     {                                                                         \
 528       /* The "to UTF-7" direction.  Flush the remaining bits and terminate    \
 529          with a '-' byte.  This will guarantee correct decoding if more       \
 530          UTF-7 encoded text is added afterwards.  */                          \
 531       int state = data->__statep->__count;                                    \
 532                                                                               \
 533       if (state & 0x18)                                                       \
 534         {                                                                     \
 535           /* Deactivate base64 encoding.  */                                  \
 536           size_t count = ((state & 0x18) >= 0x10) + 1;                        \
 537                                                                               \
 538           if (__builtin_expect (outbuf + count > outend, 0))                  \
 539             /* We don't have enough room in the output buffer.  */            \
 540             status = __GCONV_FULL_OUTPUT;                                     \
 541           else                                                                \
 542             {                                                                 \
 543               /* Write out the shift sequence.  */                            \
 544               if ((state & 0x18) >= 0x10)                                     \
 545                 *outbuf++ = base64 ((state >> 3) & ~3);                       \
 546               *outbuf++ = '-';                                                \
 547                                                                               \
 548               data->__statep->__count = 0;                                    \
 549             }                                                                 \
 550         }                                                                     \
 551       else                                                                    \
 552         data->__statep->__count = 0;                                          \
 553     }
 554
 555
 556 /* Now define the toplevel functions.  */
 557 #include <iconv/skeleton.c>