quote.c

   1 /* quote.c      library routines for the Netwide Assembler
   2  *
   3  * The Netwide Assembler is copyright (C) 1996 Simon Tatham and
   4  * Julian Hall. All rights reserved. The software is
   5  * redistributable under the license given in the file "LICENSE"
   6  * distributed in the NASM archive.
   7  */
   8
   9 #include "compiler.h"
  10
  11 #include <assert.h>
  12 #include <stdlib.h>
  13
  14 #include "nasmlib.h"
  15 #include "quote.h"
  16
  17 #define numvalue(c)  ((c)>='a' ? (c)-'a'+10 : (c)>='A' ? (c)-'A'+10 : (c)-'0')
  18
  19 char *nasm_quote(char *str, size_t len)
  20 {
  21     char c, c1, *p, *q, *nstr, *ep;
  22     bool sq_ok, dq_ok;
  23     size_t qlen;
  24
  25     sq_ok = dq_ok = true;
  26     ep = str+len;
  27     qlen = 0;                   /* Length if we need `...` quotes */
  28     for (p = str; p < ep; p++) {
  29         c = *p;
  30         switch (c) {
  31         case '\'':
  32             sq_ok = false;
  33             qlen++;
  34             break;
  35         case '\"':
  36             dq_ok = false;
  37             qlen++;
  38             break;
  39         case '`':
  40         case '\\':
  41             qlen += 2;
  42             break;
  43         default:
  44             if (c < ' ' || c > '~') {
  45                 sq_ok = dq_ok = false;
  46                 switch (c) {
  47                 case '\a':
  48                 case '\b':
  49                 case '\t':
  50                 case '\n':
  51                 case '\v':
  52                 case '\f':
  53                 case '\r':
  54                 case 27:
  55                     qlen += 2;
  56                     break;
  57                 default:
  58                     c1 = (p+1 < ep) ? p[1] : 0;
  59                     if (c > 077 || (c1 >= '0' && c1 <= '7'))
  60                         qlen += 4; /* Must use the full form */
  61                     else if (c > 07)
  62                         qlen += 3;
  63                     else
  64                         qlen += 2;
  65                     break;
  66                 }
  67             } else {
  68                 qlen++;
  69             }
  70             break;
  71         }
  72     }
  73
  74     if (sq_ok || dq_ok) {
  75         /* Use '...' or "..." */
  76         nstr = nasm_malloc(len+3);
  77         nstr[0] = nstr[len+1] = sq_ok ? '\'' : '\"';
  78         nstr[len+2] = '\0';
  79         memcpy(nstr+1, str, len);
  80     } else {
  81         /* Need to use `...` quoted syntax */
  82         nstr = nasm_malloc(qlen+3);
  83         q = nstr;
  84         *q++ = '`';
  85         for (p = str; p < ep; p++) {
  86             c = *p;
  87             switch (c) {
  88             case '`':
  89             case '\\':
  90                 *q++ = '\\';
  91                 *q++ = c;
  92                 break;
  93             case 7:
  94                 *q++ = '\\';
  95                 *q++ = 'a';
  96                 break;
  97             case 8:
  98                 *q++ = '\\';
  99                 *q++ = 'b';
 100                 break;
 101             case 9:
 102                 *q++ = '\\';
 103                 *q++ = 't';
 104                 break;
 105             case 10:
 106                 *q++ = '\\';
 107                 *q++ = 'n';
 108                 break;
 109             case 11:
 110                 *q++ = '\\';
 111                 *q++ = 'v';
 112                 break;
 113             case 12:
 114                 *q++ = '\\';
 115                 *q++ = 'f';
 116                 break;
 117             case 13:
 118                 *q++ = '\\';
 119                 *q++ = 'r';
 120                 break;
 121             case 27:
 122                 *q++ = '\\';
 123                 *q++ = 'e';
 124                 break;
 125             default:
 126                 if (c < ' ' || c > '~') {
 127                     c1 = (p+1 < ep) ? p[1] : 0;
 128                     if (c1 >= '0' && c1 <= '7')
 129                         q += sprintf(q, "\\%03o", (unsigned char)c);
 130                     else
 131                         q += sprintf(q, "\\%o", (unsigned char)c);
 132                 } else {
 133                     *q++ = c;
 134                 }
 135                 break;
 136             }
 137         }
 138         *q++ = '`';
 139         *q++ = '\0';
 140         assert((size_t)(q-nstr) == qlen+3);
 141     }
 142     return nstr;
 143 }
 144
 145 static char *emit_utf8(char *q, int32_t v)
 146 {
 147     if (v < 0) {
 148         /* Impossible - do nothing */
 149     } else if (v <= 0x7f) {
 150         *q++ = v;
 151     } else if (v <= 0x000007ff) {
 152         *q++ = 0xc0 | (v >> 6);
 153         *q++ = 0x80 | (v & 63);
 154     } else if (v <= 0x0000ffff) {
 155         *q++ = 0xe0 | (v >> 12);
 156         *q++ = 0x80 | ((v >> 6) & 63);
 157         *q++ = 0x80 | (v & 63);
 158     } else if (v <= 0x001fffff) {
 159         *q++ = 0xf0 | (v >> 18);
 160         *q++ = 0x80 | ((v >> 12) & 63);
 161         *q++ = 0x80 | ((v >> 6) & 63);
 162         *q++ = 0x80 | (v & 63);
 163     } else if (v <= 0x03ffffff) {
 164         *q++ = 0xf8 | (v >> 24);
 165         *q++ = 0x80 | ((v >> 18) & 63);
 166         *q++ = 0x80 | ((v >> 12) & 63);
 167         *q++ = 0x80 | ((v >> 6) & 63);
 168         *q++ = 0x80 | (v & 63);
 169     } else {
 170         *q++ = 0xfc | (v >> 30);
 171         *q++ = 0x80 | ((v >> 24) & 63);
 172         *q++ = 0x80 | ((v >> 18) & 63);
 173         *q++ = 0x80 | ((v >> 12) & 63);
 174         *q++ = 0x80 | ((v >> 6) & 63);
 175         *q++ = 0x80 | (v & 63);
 176     }
 177     return q;
 178 }
 179
 180 /*
 181  * Do an *in-place* dequoting of the specified string, returning the
 182  * resulting length (which may be containing embedded nulls.)
 183  *
 184  * In-place replacement is possible since the unquoted length is always
 185  * shorter than or equal to the quoted length.
 186  *
 187  * *ep points to the final quote, or to the null if improperly quoted.
 188  */
 189 size_t nasm_unquote(char *str, char **ep)
 190 {
 191     char bq;
 192     char *p, *q;
 193     char *escp = NULL;
 194     char c;
 195     enum unq_state {
 196         st_start,
 197         st_backslash,
 198         st_hex,
 199         st_oct,
 200         st_ucs,
 201     } state;
 202     int ndig = 0;
 203     int32_t nval = 0;
 204
 205     p = q = str;
 206
 207     bq = *p++;
 208     if (!bq)
 209         return 0;
 210
 211     switch (bq) {
 212     case '\'':
 213     case '\"':
 214         /* '...' or "..." string */
 215         while ((c = *p) && c != bq) {
 216             p++;
 217             *q++ = c;
 218         }
 219         *q = '\0';
 220         break;
 221
 222     case '`':
 223         /* `...` string */
 224         state = st_start;
 225
 226         while ((c = *p)) {
 227             p++;
 228             switch (state) {
 229             case st_start:
 230                 switch (c) {
 231                 case '\\':
 232                     state = st_backslash;
 233                     break;
 234                 case '`':
 235                     p--;
 236                     goto out;
 237                 default:
 238                     *q++ = c;
 239                     break;
 240                 }
 241                 break;
 242
 243             case st_backslash:
 244                 state = st_start;
 245                 escp = p;       /* Beginning of argument sequence */
 246                 nval = 0;
 247                 switch (c) {
 248                 case 'a':
 249                     *q++ = 7;
 250                     break;
 251                 case 'b':
 252                     *q++ = 8;
 253                     break;
 254                 case 'e':
 255                     *q++ = 27;
 256                     break;
 257                 case 'f':
 258                     *q++ = 12;
 259                     break;
 260                 case 'n':
 261                     *q++ = 10;
 262                     break;
 263                 case 'r':
 264                     *q++ = 13;
 265                     break;
 266                 case 't':
 267                     *q++ = 9;
 268                     break;
 269                 case 'u':
 270                     state = st_ucs;
 271                     ndig = 4;
 272                     break;
 273                 case 'U':
 274                     state = st_ucs;
 275                     ndig = 8;
 276                     break;
 277                 case 'v':
 278                     *q++ = 11;
 279                     break;
 280                 case 'x':
 281                 case 'X':
 282                     state = st_hex;
 283                     ndig = 2;
 284                     break;
 285                 case '0':
 286                 case '1':
 287                 case '2':
 288                 case '3':
 289                 case '4':
 290                 case '5':
 291                 case '6':
 292                 case '7':
 293                     state = st_oct;
 294                     ndig = 2;   /* Up to two more digits */
 295                     nval = c - '0';
 296                     break;
 297                 default:
 298                     *q++ = c;
 299                     break;
 300                 }
 301                 break;
 302
 303             case st_oct:
 304                 if (c >= '0' && c <= '7') {
 305                     nval = (nval << 3) + (c - '0');
 306                     if (!--ndig) {
 307                         *q++ = nval;
 308                         state = st_start;
 309                     }
 310                 } else {
 311                     p--;        /* Process this character again */
 312                     *q++ = nval;
 313                     state = st_start;
 314                 }
 315                 break;
 316
 317             case st_hex:
 318                 if ((c >= '0' && c <= '9') ||
 319                     (c >= 'A' && c <= 'F') ||
 320                     (c >= 'a' && c <= 'f')) {
 321                     nval = (nval << 4) + numvalue(c);
 322                     if (--ndig) {
 323                         *q++ = nval;
 324                         state = st_start;
 325                     }
 326                 } else {
 327                     p--;        /* Process this character again */
 328                     *q++ = (p > escp) ? nval : escp[-1];
 329                     state = st_start;
 330                 }
 331                 break;
 332
 333             case st_ucs:
 334                 if ((c >= '0' && c <= '9') ||
 335                     (c >= 'A' && c <= 'F') ||
 336                     (c >= 'a' && c <= 'f')) {
 337                     nval = (nval << 4) + numvalue(c);
 338                     if (!--ndig) {
 339                         q = emit_utf8(q, nval);
 340                         state = st_start;
 341                     }
 342                 } else {
 343                     p--;        /* Process this character again */
 344                     if (p > escp)
 345                         q = emit_utf8(q, nval);
 346                     else
 347                         *q++ = escp[-1];
 348                     state = st_start;
 349                 }
 350                 break;
 351             }
 352         }
 353         switch (state) {
 354         case st_start:
 355         case st_backslash:
 356             break;
 357         case st_oct:
 358             *q++ = nval;
 359             break;
 360         case st_hex:
 361             *q++ = (p > escp) ? nval : escp[-1];
 362             break;
 363         case st_ucs:
 364             if (p > escp)
 365                 q = emit_utf8(q, nval);
 366             else
 367                 *q++ = escp[-1];
 368             break;
 369         }
 370     out:
 371         break;
 372
 373     default:
 374         /* Not a quoted string, just return the input... */
 375         p = q = strchr(str, '\0');
 376         break;
 377     }
 378
 379     if (ep)
 380         *ep = p;
 381     return q-str;
 382 }
 383
 384 /*
 385  * Find the end of a quoted string; returns the pointer to the terminating
 386  * character (either the ending quote or the null character, if unterminated.)
 387  */
 388 char *nasm_skip_string(char *str)
 389 {
 390     char bq;
 391     char *p;
 392     char c;
 393     enum unq_state {
 394         st_start,
 395         st_backslash,
 396     } state;
 397
 398     bq = str[0];
 399     if (bq == '\'' || bq == '\"') {
 400         /* '...' or "..." string */
 401         for (p = str+1; *p && *p != bq; p++)
 402             ;
 403         return p;
 404     } else if (bq == '`') {
 405         /* `...` string */
 406         p = str+1;
 407         state = st_start;
 408
 409         while ((c = *p++)) {
 410             switch (state) {
 411             case st_start:
 412                 switch (c) {
 413                 case '\\':
 414                     state = st_backslash;
 415                     break;
 416                 case '`':
 417                     return p-1; /* Found the end */
 418                 default:
 419                     break;
 420                 }
 421                 break;
 422
 423             case st_backslash:
 424                 /*
 425                  * Note: for the purpose of finding the end of the string,
 426                  * all successor states to st_backslash are functionally
 427                  * equivalent to st_start, since either a backslash or
 428                  * a backquote will force a return to the st_start state.
 429                  */
 430                 state = st_start;
 431                 break;
 432             }
 433         }
 434         return p;               /* Unterminated string... */
 435     } else {
 436         return str;             /* Not a string... */
 437     }
 438 }