release/src/router/libiconv/lib/utf7.h

   1 /*
   2  * Copyright (C) 1999-2001, 2008 Free Software Foundation, Inc.
   3  * This file is part of the GNU LIBICONV Library.
   4  *
   5  * The GNU LIBICONV Library is free software; you can redistribute it
   6  * and/or modify it under the terms of the GNU Library General Public
   7  * License as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * The GNU LIBICONV Library is distributed in the hope that it will be
  11  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Library General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Library General Public
  16  * License along with the GNU LIBICONV Library; see the file COPYING.LIB.
  17  * If not, write to the Free Software Foundation, Inc., 51 Franklin Street,
  18  * Fifth Floor, Boston, MA 02110-1301, USA.
  19  */
  20
  21 /*
  22  * UTF-7
  23  */
  24
  25 /* Specification: RFC 2152 (and old RFC 1641, RFC 1642) */
  26 /* The original Base64 encoding is defined in RFC 2045. */
  27
  28 /* Set of direct characters:
  29  *   A-Z a-z 0-9 ' ( ) , - . / : ? space tab lf cr
  30  */
  31 static const unsigned char direct_tab[128/8] = {
  32   0x00, 0x26, 0x00, 0x00, 0x81, 0xf3, 0xff, 0x87,
  33   0xfe, 0xff, 0xff, 0x07, 0xfe, 0xff, 0xff, 0x07,
  34 };
  35 #define isdirect(ch) ((ch) < 128 && ((direct_tab[(ch)>>3] >> (ch & 7)) & 1))
  36
  37 /* Set of direct and optional direct characters:
  38  *   A-Z a-z 0-9 ' ( ) , - . / : ? space tab lf cr
  39  *   ! " # $ % & * ; < = > @ [ ] ^ _ ` { | }
  40  */
  41 static const unsigned char xdirect_tab[128/8] = {
  42   0x00, 0x26, 0x00, 0x00, 0xff, 0xf7, 0xff, 0xff,
  43   0xff, 0xff, 0xff, 0xef, 0xff, 0xff, 0xff, 0x3f,
  44 };
  45 #define isxdirect(ch) ((ch) < 128 && ((xdirect_tab[(ch)>>3] >> (ch & 7)) & 1))
  46
  47 /* Set of base64 characters, extended:
  48  *   A-Z a-z 0-9 + / -
  49  */
  50 static const unsigned char xbase64_tab[128/8] = {
  51   0x00, 0x00, 0x00, 0x00, 0x00, 0xa8, 0xff, 0x03,
  52   0xfe, 0xff, 0xff, 0x07, 0xfe, 0xff, 0xff, 0x07,
  53 };
  54 #define isxbase64(ch) ((ch) < 128 && ((xbase64_tab[(ch)>>3] >> (ch & 7)) & 1))
  55
  56 /*
  57  * The state is structured as follows:
  58  * bit 1..0: shift
  59  * bit 7..2: data
  60  * Precise meaning:
  61  *   shift      data
  62  *     0         0           not inside base64 encoding
  63  *     1         0           inside base64, no pending bits
  64  *     2      XXXX00         inside base64, 4 bits remain from 2nd byte
  65  *     3      XX0000         inside base64, 2 bits remain from 3rd byte
  66  */
  67
  68 static int
  69 utf7_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
  70 {
  71   state_t state = conv->istate;
  72   int count = 0; /* number of input bytes already read */
  73   if (state & 3)
  74     goto active;
  75   else
  76     goto inactive;
  77
  78 inactive:
  79   {
  80     /* Here (state & 3) == 0 */
  81     if (n < count+1)
  82       goto none;
  83     {
  84       unsigned char c = *s;
  85       if (isxdirect(c)) {
  86         *pwc = (ucs4_t) c;
  87         conv->istate = state;
  88         return count+1;
  89       }
  90       if (c == '+') {
  91         if (n < count+2)
  92           goto none;
  93         if (s[1] == '-') {
  94           *pwc = (ucs4_t) '+';
  95           conv->istate = state;
  96           return count+2;
  97         }
  98         s++; count++;
  99         state = 1;
 100         goto active;
 101       }
 102       goto ilseq;
 103     }
 104   }
 105
 106 active:
 107   {
 108     /* base64 encoding active */
 109     unsigned int wc = 0;
 110     state_t base64state = state;
 111     unsigned int kmax = 2; /* number of payload bytes to read */
 112     unsigned int k = 0; /* number of payload bytes already read */
 113     unsigned int base64count = 0; /* number of base64 bytes already read */
 114     for (;;) {
 115       unsigned char c = *s;
 116       unsigned int i;
 117       if (c >= 'A' && c <= 'Z')
 118         i = c-'A';
 119       else if (c >= 'a' && c <= 'z')
 120         i = c-'a'+26;
 121       else if (c >= '0' && c <= '9')
 122         i = c-'0'+52;
 123       else if (c == '+')
 124         i = 62;
 125       else if (c == '/')
 126         i = 63;
 127       else {
 128         /* c terminates base64 encoding */
 129         if (base64state & -4)
 130           goto ilseq; /* data must be 0, otherwise illegal */
 131         if (base64count)
 132           goto ilseq; /* partial UTF-16 characters are invalid */
 133         if (c == '-') {
 134           s++; count++;
 135         }
 136         state = 0;
 137         goto inactive;
 138       }
 139       s++; base64count++;
 140       /* read 6 bits: 0 <= i < 64 */
 141       switch (base64state & 3) {
 142         case 1: /* inside base64, no pending bits */
 143           base64state = (i << 2) | 0; break;
 144         case 0: /* inside base64, 6 bits remain from 1st byte */
 145           wc = (wc << 8) | (base64state & -4) | (i >> 4); k++;
 146           base64state = ((i & 15) << 4) | 2; break;
 147         case 2: /* inside base64, 4 bits remain from 2nd byte */
 148           wc = (wc << 8) | (base64state & -4) | (i >> 2); k++;
 149           base64state = ((i & 3) << 6) | 3; break;
 150         case 3: /* inside base64, 2 bits remain from 3rd byte */
 151           wc = (wc << 8) | (base64state & -4) | i; k++;
 152           base64state = 1; break;
 153       }
 154       if (k == kmax) {
 155         /* UTF-16: When we see a High Surrogate, we must also decode
 156            the following Low Surrogate. */
 157         if (kmax == 2 && (wc >= 0xd800 && wc < 0xdc00))
 158           kmax = 4;
 159         else
 160           break;
 161       }
 162       if (n < count+base64count+1)
 163         goto none;
 164     }
 165     /* Here k = kmax > 0, hence base64count > 0. */
 166     if ((base64state & 3) == 0) abort();
 167     if (kmax == 4) {
 168       ucs4_t wc1 = wc >> 16;
 169       ucs4_t wc2 = wc & 0xffff;
 170       if (!(wc1 >= 0xd800 && wc1 < 0xdc00)) abort();
 171       if (!(wc2 >= 0xdc00 && wc2 < 0xe000)) goto ilseq;
 172       *pwc = 0x10000 + ((wc1 - 0xd800) << 10) + (wc2 - 0xdc00);
 173     } else {
 174       *pwc = wc;
 175     }
 176     conv->istate = base64state;
 177     return count+base64count;
 178   }
 179
 180 none:
 181   conv->istate = state;
 182   return RET_TOOFEW(count);
 183
 184 ilseq:
 185   conv->istate = state;
 186   return RET_SHIFT_ILSEQ(count);
 187 }
 188
 189 /*
 190  * The state is structured as follows:
 191  * bit 1..0: shift
 192  * bit 7..2: data
 193  * Precise meaning:
 194  *   shift      data
 195  *     0         0           not inside base64 encoding
 196  *     1         0           inside base64, no pending bits
 197  *     2       XX00          inside base64, 2 bits known for 2nd byte
 198  *     3       XXXX          inside base64, 4 bits known for 3rd byte
 199  */
 200
 201 /* Define this to 1 if you want the so-called "optional direct" characters
 202       ! " # $ % & * ; < = > @ [ ] ^ _ ` { | }
 203    to be encoded. Define to 0 if you want them to be passed straight through,
 204    like the so-called "direct" characters.
 205    We set this to 1 because it's safer.
 206  */
 207 #define UTF7_ENCODE_OPTIONAL_CHARS 1
 208
 209 static int
 210 utf7_wctomb (conv_t conv, unsigned char *r, ucs4_t iwc, int n)
 211 {
 212   state_t state = conv->ostate;
 213   unsigned int wc = iwc;
 214   int count = 0;
 215   if (state & 3)
 216     goto active;
 217
 218 /*inactive:*/
 219   {
 220     if (UTF7_ENCODE_OPTIONAL_CHARS ? isdirect(wc) : isxdirect(wc)) {
 221       r[0] = (unsigned char) wc;
 222       /*conv->ostate = state;*/
 223       return 1;
 224     } else {
 225       *r++ = '+';
 226       if (wc == '+') {
 227         if (n < 2)
 228           return RET_TOOSMALL;
 229         *r = '-';
 230         /*conv->ostate = state;*/
 231         return 2;
 232       }
 233       count = 1;
 234       state = 1;
 235       goto active;
 236     }
 237   }
 238
 239 active:
 240   {
 241     /* base64 encoding active */
 242     if (UTF7_ENCODE_OPTIONAL_CHARS ? isdirect(wc) : isxdirect(wc)) {
 243       /* deactivate base64 encoding */
 244       count += ((state & 3) >= 2 ? 1 : 0) + (isxbase64(wc) ? 1 : 0) + 1;
 245       if (n < count)
 246         return RET_TOOSMALL;
 247       if ((state & 3) >= 2) {
 248         unsigned int i = state & -4;
 249         unsigned char c;
 250         if (i < 26)
 251           c = i+'A';
 252         else if (i < 52)
 253           c = i-26+'a';
 254         else if (i < 62)
 255           c = i-52+'0';
 256         else if (i == 62)
 257           c = '+';
 258         else if (i == 63)
 259           c = '/';
 260         else
 261           abort();
 262         *r++ = c;
 263       }
 264       if (isxbase64(wc))
 265         *r++ = '-';
 266       state = 0;
 267       *r++ = (unsigned char) wc;
 268       conv->ostate = state;
 269       return count;
 270     } else {
 271       unsigned int k; /* number of payload bytes to write */
 272       if (wc < 0x10000) {
 273         k = 2;
 274         count += ((state & 3) >= 2 ? 3 : 2);
 275       } else if (wc < 0x110000) {
 276         unsigned int wc1 = 0xd800 + ((wc - 0x10000) >> 10);
 277         unsigned int wc2 = 0xdc00 + ((wc - 0x10000) & 0x3ff);
 278         wc = (wc1 << 16) | wc2;
 279         k = 4;
 280         count += ((state & 3) >= 3 ? 6 : 5);
 281       } else
 282         return RET_ILUNI;
 283       if (n < count)
 284         return RET_TOOSMALL;
 285       for (;;) {
 286         unsigned int i;
 287         unsigned char c;
 288         switch (state & 3) {
 289           case 0: /* inside base64, 6 bits known for 4th byte */
 290             c = (state & -4) >> 2; state = 1; break;
 291           case 1: /* inside base64, no pending bits */
 292             i = (wc >> (8 * --k)) & 0xff;
 293             c = i >> 2; state = ((i & 3) << 4) | 2; break;
 294           case 2: /* inside base64, 2 bits known for 2nd byte */
 295             i = (wc >> (8 * --k)) & 0xff;
 296             c = (state & -4) | (i >> 4); state = ((i & 15) << 2) | 3; break;
 297           case 3: /* inside base64, 4 bits known for 3rd byte */
 298             i = (wc >> (8 * --k)) & 0xff;
 299             c = (state & -4) | (i >> 6); state = ((i & 63) << 2) | 0; break;
 300           default: abort(); /* stupid gcc */
 301         }
 302         if (c < 26)
 303           c = c+'A';
 304         else if (c < 52)
 305           c = c-26+'a';
 306         else if (c < 62)
 307           c = c-52+'0';
 308         else if (c == 62)
 309           c = '+';
 310         else if (c == 63)
 311           c = '/';
 312         else
 313           abort();
 314         *r++ = c;
 315         if ((state & 3) && (k == 0))
 316           break;
 317       }
 318       conv->ostate = state;
 319       return count;
 320     }
 321   }
 322 }
 323
 324 static int
 325 utf7_reset (conv_t conv, unsigned char *r, int n)
 326 {
 327   state_t state = conv->ostate;
 328   if (state & 3) {
 329     /* deactivate base64 encoding */
 330     unsigned int count = ((state & 3) >= 2 ? 1 : 0) + 1;
 331     if (n < count)
 332       return RET_TOOSMALL;
 333     if ((state & 3) >= 2) {
 334       unsigned int i = state & -4;
 335       unsigned char c;
 336       if (i < 26)
 337         c = i+'A';
 338       else if (i < 52)
 339         c = i-26+'a';
 340       else if (i < 62)
 341         c = i-52+'0';
 342       else if (i == 62)
 343         c = '+';
 344       else if (i == 63)
 345         c = '/';
 346       else
 347         abort();
 348       *r++ = c;
 349     }
 350     *r++ = '-';
 351     /* conv->ostate = 0; will be done by the caller */
 352     return count;
 353   } else
 354     return 0;
 355 }