re.c

   1 /**********************************************************************
   2
   3   re.c -
   4
   5   $Author$
   6   created at: Mon Aug  9 18:24:49 JST 1993
   7
   8   Copyright (C) 1993-2007 Yukihiro Matsumoto
   9
  10 **********************************************************************/
  11
  12 #include "ruby/ruby.h"
  13 #include "ruby/re.h"
  14 #include "ruby/encoding.h"
  15 #include "ruby/util.h"
  16 #include "regint.h"
  17 #include <ctype.h>
  18
  19 VALUE rb_eRegexpError;
  20
  21 typedef char onig_errmsg_buffer[ONIG_MAX_ERROR_MESSAGE_LEN];
  22
  23 #define BEG(no) regs->beg[no]
  24 #define END(no) regs->end[no]
  25
  26 #if 'a' == 97   /* it's ascii */
  27 static const char casetable[] = {
  28         '\000', '\001', '\002', '\003', '\004', '\005', '\006', '\007',
  29         '\010', '\011', '\012', '\013', '\014', '\015', '\016', '\017',
  30         '\020', '\021', '\022', '\023', '\024', '\025', '\026', '\027',
  31         '\030', '\031', '\032', '\033', '\034', '\035', '\036', '\037',
  32         /* ' '     '!'     '"'     '#'     '$'     '%'     '&'     ''' */
  33         '\040', '\041', '\042', '\043', '\044', '\045', '\046', '\047',
  34         /* '('     ')'     '*'     '+'     ','     '-'     '.'     '/' */
  35         '\050', '\051', '\052', '\053', '\054', '\055', '\056', '\057',
  36         /* '0'     '1'     '2'     '3'     '4'     '5'     '6'     '7' */
  37         '\060', '\061', '\062', '\063', '\064', '\065', '\066', '\067',
  38         /* '8'     '9'     ':'     ';'     '<'     '='     '>'     '?' */
  39         '\070', '\071', '\072', '\073', '\074', '\075', '\076', '\077',
  40         /* '@'     'A'     'B'     'C'     'D'     'E'     'F'     'G' */
  41         '\100', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
  42         /* 'H'     'I'     'J'     'K'     'L'     'M'     'N'     'O' */
  43         '\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
  44         /* 'P'     'Q'     'R'     'S'     'T'     'U'     'V'     'W' */
  45         '\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
  46         /* 'X'     'Y'     'Z'     '['     '\'     ']'     '^'     '_' */
  47         '\170', '\171', '\172', '\133', '\134', '\135', '\136', '\137',
  48         /* '`'     'a'     'b'     'c'     'd'     'e'     'f'     'g' */
  49         '\140', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
  50         /* 'h'     'i'     'j'     'k'     'l'     'm'     'n'     'o' */
  51         '\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
  52         /* 'p'     'q'     'r'     's'     't'     'u'     'v'     'w' */
  53         '\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
  54         /* 'x'     'y'     'z'     '{'     '|'     '}'     '~' */
  55         '\170', '\171', '\172', '\173', '\174', '\175', '\176', '\177',
  56         '\200', '\201', '\202', '\203', '\204', '\205', '\206', '\207',
  57         '\210', '\211', '\212', '\213', '\214', '\215', '\216', '\217',
  58         '\220', '\221', '\222', '\223', '\224', '\225', '\226', '\227',
  59         '\230', '\231', '\232', '\233', '\234', '\235', '\236', '\237',
  60         '\240', '\241', '\242', '\243', '\244', '\245', '\246', '\247',
  61         '\250', '\251', '\252', '\253', '\254', '\255', '\256', '\257',
  62         '\260', '\261', '\262', '\263', '\264', '\265', '\266', '\267',
  63         '\270', '\271', '\272', '\273', '\274', '\275', '\276', '\277',
  64         '\300', '\301', '\302', '\303', '\304', '\305', '\306', '\307',
  65         '\310', '\311', '\312', '\313', '\314', '\315', '\316', '\317',
  66         '\320', '\321', '\322', '\323', '\324', '\325', '\326', '\327',
  67         '\330', '\331', '\332', '\333', '\334', '\335', '\336', '\337',
  68         '\340', '\341', '\342', '\343', '\344', '\345', '\346', '\347',
  69         '\350', '\351', '\352', '\353', '\354', '\355', '\356', '\357',
  70         '\360', '\361', '\362', '\363', '\364', '\365', '\366', '\367',
  71         '\370', '\371', '\372', '\373', '\374', '\375', '\376', '\377',
  72 };
  73 #else
  74 # error >>> "You lose. You will need a translation table for your character set." <<<
  75 #endif
  76
  77 int
  78 rb_memcicmp(const void *x, const void *y, long len)
  79 {
  80     const unsigned char *p1 = x, *p2 = y;
  81     int tmp;
  82
  83     while (len--) {
  84         if ((tmp = casetable[(unsigned)*p1++] - casetable[(unsigned)*p2++]))
  85             return tmp;
  86     }
  87     return 0;
  88 }
  89
  90 #undef rb_memcmp
  91
  92 int
  93 rb_memcmp(const void *p1, const void *p2, long len)
  94 {
  95     return memcmp(p1, p2, len);
  96 }
  97
  98 static inline long
  99 rb_memsearch_ss(const unsigned char *xs, long m, const unsigned char *ys, long n)
 100 {
 101     const unsigned char *x = xs, *xe = xs + m;
 102     const unsigned char *y = ys, *ye = ys + n;
 103 #ifndef VALUE_MAX
 104 # if SIZEOF_VALUE == 8
 105 #  define VALUE_MAX 0xFFFFFFFFFFFFFFFFULL
 106 # elif SIZEOF_VALUE == 4
 107 #  define VALUE_MAX 0xFFFFFFFFUL
 108 # endif
 109 #endif
 110     VALUE hx, hy, mask = VALUE_MAX >> ((SIZEOF_VALUE - m) * CHAR_BIT);
 111
 112     if (m > SIZEOF_VALUE)
 113         rb_bug("!!too long pattern string!!");
 114
 115         /* Prepare hash value */
 116     for (hx = *x++, hy = *y++; x < xe; ++x, ++y) {
 117         hx <<= CHAR_BIT;
 118         hy <<= CHAR_BIT;
 119         hx |= *x;
 120         hy |= *y;
 121     }
 122     /* Searching */
 123     while (hx != hy) {
 124         if (y == ye)
 125             return -1;
 126         hy <<= CHAR_BIT;
 127         hy |= *y;
 128         hy &= mask;
 129         y++;
 130     }
 131     return y - ys - m;
 132 }
 133
 134 static inline long
 135 rb_memsearch_qs(const unsigned char *xs, long m, const unsigned char *ys, long n)
 136 {
 137     const unsigned char *x = xs, *xe = xs + m;
 138     const unsigned char *y = ys;
 139     VALUE i, qstable[256];
 140
 141     /* Preprocessing */
 142     for (i = 0; i < 256; ++i)
 143         qstable[i] = m + 1;
 144     for (; x < xe; ++x)
 145         qstable[*x] = xe - x;
 146     /* Searching */
 147     for (; y + m <= ys + n; y += *(qstable + y[m])) {
 148         if (*xs == *y && memcmp(xs, y, m) == 0)
 149             return y - ys;
 150     }
 151     return -1;
 152 }
 153
 154 static inline unsigned int
 155 rb_memsearch_qs_utf8_hash(const unsigned char *x)
 156 {
 157     register const unsigned int mix = 8353;
 158     register unsigned int h = *x;
 159     if (h < 0xC0) {
 160         return h + 256;
 161     }
 162     else if (h < 0xE0) {
 163         h *= mix;
 164         h += x[1];
 165     }
 166     else if (h < 0xF0) {
 167         h *= mix;
 168         h += x[1];
 169         h *= mix;
 170         h += x[2];
 171     }
 172     else if (h < 0xF5) {
 173         h *= mix;
 174         h += x[1];
 175         h *= mix;
 176         h += x[2];
 177         h *= mix;
 178         h += x[3];
 179     }
 180     else {
 181         return h + 256;
 182     }
 183     return (unsigned char)h;
 184 }
 185
 186 static inline long
 187 rb_memsearch_qs_utf8(const unsigned char *xs, long m, const unsigned char *ys, long n)
 188 {
 189     const unsigned char *x = xs, *xe = xs + m;
 190     const unsigned char *y = ys;
 191     VALUE i, qstable[512];
 192
 193     /* Preprocessing */
 194     for (i = 0; i < 512; ++i) {
 195         qstable[i] = m + 1;
 196     }
 197     for (; x < xe; ++x) {
 198         qstable[rb_memsearch_qs_utf8_hash(x)] = xe - x;
 199     }
 200     /* Searching */
 201     for (; y + m <= ys + n; y += qstable[rb_memsearch_qs_utf8_hash(y+m)]) {
 202         if (*xs == *y && memcmp(xs, y, m) == 0)
 203             return y - ys;
 204     }
 205     return -1;
 206 }
 207
 208 long
 209 rb_memsearch(const void *x0, long m, const void *y0, long n, rb_encoding *enc)
 210 {
 211     const unsigned char *x = x0, *y = y0;
 212
 213     if (m > n) return -1;
 214     else if (m == n) {
 215         return memcmp(x0, y0, m) == 0 ? 0 : -1;
 216     }
 217     else if (m < 1) {
 218         return 0;
 219     }
 220     else if (m == 1) {
 221         const unsigned char *ys = y, *ye = ys + n;
 222         for (; y < ye; ++y) {
 223             if (*x == *y)
 224                 return y - ys;
 225         }
 226         return -1;
 227     }
 228     else if (m <= SIZEOF_VALUE) {
 229         return rb_memsearch_ss(x0, m, y0, n);
 230     }
 231     else if (enc == rb_utf8_encoding()){
 232         return rb_memsearch_qs_utf8(x0, m, y0, n);
 233     }
 234     else {
 235         return rb_memsearch_qs(x0, m, y0, n);
 236     }
 237 }
 238
 239 #define REG_LITERAL FL_USER5
 240 #define REG_ENCODING_NONE FL_USER6
 241
 242 #define KCODE_FIXED FL_USER4
 243
 244 #define ARG_REG_OPTION_MASK \
 245     (ONIG_OPTION_IGNORECASE|ONIG_OPTION_MULTILINE|ONIG_OPTION_EXTEND)
 246 #define ARG_ENCODING_FIXED    16
 247 #define ARG_ENCODING_NONE     32
 248
 249 static int
 250 char_to_option(int c)
 251 {
 252     int val;
 253
 254     switch (c) {
 255       case 'i':
 256         val = ONIG_OPTION_IGNORECASE;
 257         break;
 258       case 'x':
 259         val = ONIG_OPTION_EXTEND;
 260         break;
 261       case 'm':
 262         val = ONIG_OPTION_MULTILINE;
 263         break;
 264       default:
 265         val = 0;
 266         break;
 267     }
 268     return val;
 269 }
 270
 271 static char *
 272 option_to_str(char str[4], int options)
 273 {
 274     char *p = str;
 275     if (options & ONIG_OPTION_MULTILINE) *p++ = 'm';
 276     if (options & ONIG_OPTION_IGNORECASE) *p++ = 'i';
 277     if (options & ONIG_OPTION_EXTEND) *p++ = 'x';
 278     *p = 0;
 279     return str;
 280 }
 281
 282 extern int
 283 rb_char_to_option_kcode(int c, int *option, int *kcode)
 284 {
 285     *option = 0;
 286
 287     switch (c) {
 288       case 'n':
 289         *kcode = -1;
 290         return (*option = ARG_ENCODING_NONE);
 291       case 'e':
 292         *kcode = rb_enc_find_index("EUC-JP");
 293         break;
 294       case 's':
 295         *kcode = rb_enc_find_index("Windows-31J");
 296         break;
 297       case 'u':
 298         *kcode = rb_enc_find_index("UTF-8");
 299         break;
 300       default:
 301         *kcode = -1;
 302         return (*option = char_to_option(c));
 303     }
 304     *option = ARG_ENCODING_FIXED;
 305     return 1;
 306 }
 307
 308 static void
 309 rb_reg_check(VALUE re)
 310 {
 311     if (!RREGEXP(re)->ptr || !RREGEXP_SRC(re) || !RREGEXP_SRC_PTR(re)) {
 312         rb_raise(rb_eTypeError, "uninitialized Regexp");
 313     }
 314 }
 315
 316 static void
 317 rb_reg_expr_str(VALUE str, const char *s, long len)
 318 {
 319     rb_encoding *enc = rb_enc_get(str);
 320     const char *p, *pend;
 321     int need_escape = 0;
 322     int c, clen;
 323
 324     p = s; pend = p + len;
 325     while (p<pend) {
 326         c = rb_enc_ascget(p, pend, &clen, enc);
 327         if (c == -1) {
 328             p += mbclen(p, pend, enc);
 329         }
 330         else if (c != '/' && rb_enc_isprint(c, enc)) {
 331             p += clen;
 332         }
 333         else {
 334             need_escape = 1;
 335             break;
 336         }
 337     }
 338     if (!need_escape) {
 339         rb_str_buf_cat(str, s, len);
 340     }
 341     else {
 342         p = s;
 343         while (p<pend) {
 344             c = rb_enc_ascget(p, pend, &clen, enc);
 345             if (c == '\\' && p+clen < pend) {
 346                 int n = clen + mbclen(p+clen, pend, enc);
 347                 rb_str_buf_cat(str, p, n);
 348                 p += n;
 349                 continue;
 350             }
 351             else if (c == '/') {
 352                 char c = '\\';
 353                 rb_str_buf_cat(str, &c, 1);
 354                 rb_str_buf_cat(str, p, clen);
 355             }
 356             else if (c == -1) {
 357                 int l = mbclen(p, pend, enc);
 358                 rb_str_buf_cat(str, p, l);
 359                 p += l;
 360                 continue;
 361             }
 362             else if (rb_enc_isprint(c, enc)) {
 363                 rb_str_buf_cat(str, p, clen);
 364             }
 365             else if (!rb_enc_isspace(c, enc)) {
 366                 char b[8];
 367
 368                 sprintf(b, "\\x%02X", c);
 369                 rb_str_buf_cat(str, b, 4);
 370             }
 371             else {
 372                 rb_str_buf_cat(str, p, clen);
 373             }
 374             p += clen;
 375         }
 376     }
 377 }
 378
 379 static VALUE
 380 rb_reg_desc(const char *s, long len, VALUE re)
 381 {
 382     VALUE str = rb_str_buf_new2("/");
 383
 384     rb_enc_copy(str, re);
 385     rb_reg_expr_str(str, s, len);
 386     rb_str_buf_cat2(str, "/");
 387     if (re) {
 388         char opts[4];
 389         rb_reg_check(re);
 390         if (*option_to_str(opts, RREGEXP(re)->ptr->options))
 391             rb_str_buf_cat2(str, opts);
 392     }
 393     OBJ_INFECT(str, re);
 394     return str;
 395 }
 396
 397
 398 /*
 399  *  call-seq:
 400  *      rxp.source   => str
 401  *
 402  *  Returns the original string of the pattern.
 403  *
 404  *      /ab+c/ix.source #=> "ab+c"
 405  *
 406  *  Note that escape sequences are retained as is.
 407  *
 408  *     /\x20\+/.source  #=> "\\x20\\+"
 409  *
 410  */
 411
 412 static VALUE
 413 rb_reg_source(VALUE re)
 414 {
 415     VALUE str;
 416
 417     rb_reg_check(re);
 418     str = rb_enc_str_new(RREGEXP_SRC_PTR(re),RREGEXP_SRC_LEN(re), rb_enc_get(re));
 419     if (OBJ_TAINTED(re)) OBJ_TAINT(str);
 420     return str;
 421 }
 422
 423 /*
 424  * call-seq:
 425  *    rxp.inspect   => string
 426  *
 427  * Produce a nicely formatted string-version of _rxp_. Perhaps surprisingly,
 428  * <code>#inspect</code> actually produces the more natural version of
 429  * the string than <code>#to_s</code>.
 430  *
 431  *      /ab+c/ix.inspect        #=> "/ab+c/ix"
 432  *
 433  */
 434
 435 static VALUE
 436 rb_reg_inspect(VALUE re)
 437 {
 438     rb_reg_check(re);
 439     return rb_reg_desc(RREGEXP_SRC_PTR(re), RREGEXP_SRC_LEN(re), re);
 440 }
 441
 442
 443 /*
 444  *  call-seq:
 445  *     rxp.to_s   => str
 446  *
 447  *  Returns a string containing the regular expression and its options (using the
 448  *  <code>(?opts:source)</code> notation. This string can be fed back in to
 449  *  <code>Regexp::new</code> to a regular expression with the same semantics as
 450  *  the original. (However, <code>Regexp#==</code> may not return true when
 451  *  comparing the two, as the source of the regular expression itself may
 452  *  differ, as the example shows).  <code>Regexp#inspect</code> produces a
 453  *  generally more readable version of <i>rxp</i>.
 454  *
 455  *      r1 = /ab+c/ix           #=> /ab+c/ix
 456  *      s1 = r1.to_s            #=> "(?ix-m:ab+c)"
 457  *      r2 = Regexp.new(s1)     #=> /(?ix-m:ab+c)/
 458  *      r1 == r2                #=> false
 459  *      r1.source               #=> "ab+c"
 460  *      r2.source               #=> "(?ix-m:ab+c)"
 461  */
 462
 463 static VALUE
 464 rb_reg_to_s(VALUE re)
 465 {
 466     int options, opt;
 467     const int embeddable = ONIG_OPTION_MULTILINE|ONIG_OPTION_IGNORECASE|ONIG_OPTION_EXTEND;
 468     long len;
 469     const UChar* ptr;
 470     VALUE str = rb_str_buf_new2("(?");
 471     char optbuf[5];
 472
 473     rb_reg_check(re);
 474
 475     rb_enc_copy(str, re);
 476     options = RREGEXP(re)->ptr->options;
 477     ptr = (UChar*)RREGEXP_SRC_PTR(re);
 478     len = RREGEXP_SRC_LEN(re);
 479   again:
 480     if (len >= 4 && ptr[0] == '(' && ptr[1] == '?') {
 481         int err = 1;
 482         ptr += 2;
 483         if ((len -= 2) > 0) {
 484             do {
 485                 opt = char_to_option((int )*ptr);
 486                 if (opt != 0) {
 487                     options |= opt;
 488                 }
 489                 else {
 490                     break;
 491                 }
 492                 ++ptr;
 493             } while (--len > 0);
 494         }
 495         if (len > 1 && *ptr == '-') {
 496             ++ptr;
 497             --len;
 498             do {
 499                 opt = char_to_option((int )*ptr);
 500                 if (opt != 0) {
 501                     options &= ~opt;
 502                 }
 503                 else {
 504                     break;
 505                 }
 506                 ++ptr;
 507             } while (--len > 0);
 508         }
 509         if (*ptr == ')') {
 510             --len;
 511             ++ptr;
 512             goto again;
 513         }
 514         if (*ptr == ':' && ptr[len-1] == ')') {
 515             int r;
 516             Regexp *rp;
 517             r = onig_alloc_init(&rp, ONIG_OPTION_DEFAULT,
 518                                 ONIGENC_CASE_FOLD_DEFAULT,
 519                                 rb_enc_get(re),
 520                                 OnigDefaultSyntax);
 521             if (r == 0) {
 522                  ++ptr;
 523                  len -= 2;
 524                  err = (onig_compile(rp, ptr, ptr + len, NULL) != 0);
 525             }
 526             onig_free(rp);
 527         }
 528         if (err) {
 529             options = RREGEXP(re)->ptr->options;
 530             ptr = (UChar*)RREGEXP_SRC_PTR(re);
 531             len = RREGEXP_SRC_LEN(re);
 532         }
 533     }
 534
 535     if (*option_to_str(optbuf, options)) rb_str_buf_cat2(str, optbuf);
 536
 537     if ((options & embeddable) != embeddable) {
 538         optbuf[0] = '-';
 539         option_to_str(optbuf + 1, ~options);
 540         rb_str_buf_cat2(str, optbuf);
 541     }
 542
 543     rb_str_buf_cat2(str, ":");
 544     rb_reg_expr_str(str, (char*)ptr, len);
 545     rb_str_buf_cat2(str, ")");
 546     rb_enc_copy(str, re);
 547
 548     OBJ_INFECT(str, re);
 549     return str;
 550 }
 551
 552 static void
 553 rb_reg_raise(const char *s, long len, const char *err, VALUE re)
 554 {
 555     VALUE desc = rb_reg_desc(s, len, re);
 556
 557     rb_raise(rb_eRegexpError, "%s: %s", err, RSTRING_PTR(desc));
 558 }
 559
 560 static VALUE
 561 rb_enc_reg_error_desc(const char *s, long len, rb_encoding *enc, int options, const char *err)
 562 {
 563     char opts[6];
 564     VALUE desc = rb_str_buf_new2(err);
 565
 566     rb_enc_associate(desc, enc);
 567     rb_str_buf_cat2(desc, ": /");
 568     rb_reg_expr_str(desc, s, len);
 569     opts[0] = '/';
 570     option_to_str(opts + 1, options);
 571     rb_str_buf_cat2(desc, opts);
 572     return rb_exc_new3(rb_eRegexpError, desc);
 573 }
 574
 575 static void
 576 rb_enc_reg_raise(const char *s, long len, rb_encoding *enc, int options, const char *err)
 577 {
 578     rb_exc_raise(rb_enc_reg_error_desc(s, len, enc, options, err));
 579 }
 580
 581 static VALUE
 582 rb_reg_error_desc(VALUE str, int options, const char *err)
 583 {
 584     return rb_enc_reg_error_desc(RSTRING_PTR(str), RSTRING_LEN(str),
 585                                  rb_enc_get(str), options, err);
 586 }
 587
 588 static void
 589 rb_reg_raise_str(VALUE str, int options, const char *err)
 590 {
 591     rb_exc_raise(rb_reg_error_desc(str, options, err));
 592 }
 593
 594
 595 /*
 596  *  call-seq:
 597  *     rxp.casefold?   => true or false
 598  *
 599  *  Returns the value of the case-insensitive flag.
 600  *
 601  *      /a/.casefold?           #=> false
 602  *      /a/i.casefold?          #=> true
 603  *      /(?i:a)/.casefold?      #=> false
 604  */
 605
 606 static VALUE
 607 rb_reg_casefold_p(VALUE re)
 608 {
 609     rb_reg_check(re);
 610     if (RREGEXP(re)->ptr->options & ONIG_OPTION_IGNORECASE) return Qtrue;
 611     return Qfalse;
 612 }
 613
 614
 615 /*
 616  *  call-seq:
 617  *     rxp.options   => fixnum
 618  *
 619  *  Returns the set of bits corresponding to the options used when creating this
 620  *  Regexp (see <code>Regexp::new</code> for details. Note that additional bits
 621  *  may be set in the returned options: these are used internally by the regular
 622  *  expression code. These extra bits are ignored if the options are passed to
 623  *  <code>Regexp::new</code>.
 624  *
 625  *     Regexp::IGNORECASE                  #=> 1
 626  *     Regexp::EXTENDED                    #=> 2
 627  *     Regexp::MULTILINE                   #=> 4
 628  *
 629  *     /cat/.options                       #=> 0
 630  *     /cat/ix.options                     #=> 3
 631  *     Regexp.new('cat', true).options     #=> 1
 632  *     /\xa1\xa2/e.options                 #=> 16
 633  *
 634  *     r = /cat/ix
 635  *     Regexp.new(r.source, r.options)     #=> /cat/ix
 636  */
 637
 638 static VALUE
 639 rb_reg_options_m(VALUE re)
 640 {
 641     int options = rb_reg_options(re);
 642     return INT2NUM(options);
 643 }
 644
 645 static int
 646 reg_names_iter(const OnigUChar *name, const OnigUChar *name_end,
 647           int back_num, int *back_refs, OnigRegex regex, void *arg)
 648 {
 649     VALUE ary = (VALUE)arg;
 650     rb_ary_push(ary, rb_str_new((const char *)name, name_end-name));
 651     return 0;
 652 }
 653
 654 /*
 655  * call-seq:
 656  *    rxp.names   => [name1, name2, ...]
 657  *
 658  * Returns a list of names of captures as an array of strings.
 659  *
 660  *     /(?<foo>.)(?<bar>.)(?<baz>.)/.names
 661  *     #=> ["foo", "bar", "baz"]
 662  *
 663  *     /(?<foo>.)(?<foo>.)/.names
 664  *     #=> ["foo"]
 665  *
 666  *     /(.)(.)/.names
 667  *     #=> []
 668  */
 669
 670 static VALUE
 671 rb_reg_names(VALUE re)
 672 {
 673     VALUE ary = rb_ary_new();
 674     rb_reg_check(re);
 675     onig_foreach_name(RREGEXP(re)->ptr, reg_names_iter, (void*)ary);
 676     return ary;
 677 }
 678
 679 static int
 680 reg_named_captures_iter(const OnigUChar *name, const OnigUChar *name_end,
 681           int back_num, int *back_refs, OnigRegex regex, void *arg)
 682 {
 683     VALUE hash = (VALUE)arg;
 684     VALUE ary = rb_ary_new2(back_num);
 685     int i;
 686
 687     for(i = 0; i < back_num; i++)
 688         rb_ary_store(ary, i, INT2NUM(back_refs[i]));
 689
 690     rb_hash_aset(hash, rb_str_new((const char*)name, name_end-name),ary);
 691
 692     return 0;
 693 }
 694
 695 /*
 696  * call-seq:
 697  *    rxp.named_captures  => hash
 698  *
 699  * Returns a hash representing information about named captures of <i>rxp</i>.
 700  *
 701  * A key of the hash is a name of the named captures.
 702  * A value of the hash is an array which is list of indexes of corresponding
 703  * named captures.
 704  *
 705  *    /(?<foo>.)(?<bar>.)/.named_captures
 706  *    #=> {"foo"=>[1], "bar"=>[2]}
 707  *
 708  *    /(?<foo>.)(?<foo>.)/.named_captures
 709  *    #=> {"foo"=>[1, 2]}
 710  *
 711  * If there are no named captures, an empty hash is returned.
 712  *
 713  *    /(.)(.)/.named_captures
 714  *    #=> {}
 715  */
 716
 717 static VALUE
 718 rb_reg_named_captures(VALUE re)
 719 {
 720     VALUE hash = rb_hash_new();
 721     rb_reg_check(re);
 722     onig_foreach_name(RREGEXP(re)->ptr, reg_named_captures_iter, (void*)hash);
 723     return hash;
 724 }
 725
 726 static Regexp*
 727 make_regexp(const char *s, long len, rb_encoding *enc, int flags, onig_errmsg_buffer err)
 728 {
 729     Regexp *rp;
 730     int r;
 731     OnigErrorInfo einfo;
 732
 733     /* Handle escaped characters first. */
 734
 735     /* Build a copy of the string (in dest) with the
 736        escaped characters translated,  and generate the regex
 737        from that.
 738     */
 739
 740     r = onig_alloc_init(&rp, flags, ONIGENC_CASE_FOLD_DEFAULT,
 741                         enc, OnigDefaultSyntax);
 742     if (r) {
 743         onig_error_code_to_str((UChar*)err, r);
 744         return 0;
 745     }
 746
 747     r = onig_compile(rp, (UChar*)s, (UChar*)(s + len), &einfo);
 748
 749     if (r != 0) {
 750         onig_free(rp);
 751         (void )onig_error_code_to_str((UChar*)err, r, &einfo);
 752         return 0;
 753     }
 754     return rp;
 755 }
 756
 757
 758 /*
 759  *  Document-class: MatchData
 760  *
 761  *  <code>MatchData</code> is the type of the special variable <code>$~</code>,
 762  *  and is the type of the object returned by <code>Regexp#match</code> and
 763  *  <code>Regexp.last_match</code>. It encapsulates all the results of a pattern
 764  *  match, results normally accessed through the special variables
 765  *  <code>$&</code>, <code>$'</code>, <code>$`</code>, <code>$1</code>,
 766  *  <code>$2</code>, and so on.
 767  *
 768  */
 769
 770 VALUE rb_cMatch;
 771
 772 static VALUE
 773 match_alloc(VALUE klass)
 774 {
 775     NEWOBJ(match, struct RMatch);
 776     OBJSETUP(match, klass, T_MATCH);
 777
 778     match->str = 0;
 779     match->rmatch = 0;
 780     match->regexp = 0;
 781     match->rmatch = ALLOC(struct rmatch);
 782     MEMZERO(match->rmatch, struct rmatch, 1);
 783
 784     return (VALUE)match;
 785 }
 786
 787 typedef struct {
 788     int byte_pos;
 789     int char_pos;
 790 } pair_t;
 791
 792 static int
 793 pair_byte_cmp(const void *pair1, const void *pair2)
 794 {
 795     return ((pair_t*)pair1)->byte_pos - ((pair_t*)pair2)->byte_pos;
 796 }
 797
 798 static void
 799 update_char_offset(VALUE match)
 800 {
 801     struct rmatch *rm = RMATCH(match)->rmatch;
 802     struct re_registers *regs;
 803     int num_regs;
 804     int i, num_pos, c;
 805     char *s, *p, *q, *e;
 806     rb_encoding *enc;
 807     pair_t *pairs;
 808
 809     if (rm->char_offset_updated)
 810         return;
 811
 812     regs = &rm->regs;
 813     num_regs = rm->regs.num_regs;
 814
 815     if (rm->char_offset_num_allocated < num_regs) {
 816         REALLOC_N(rm->char_offset, struct rmatch_offset, num_regs);
 817         rm->char_offset_num_allocated = num_regs;
 818     }
 819
 820     enc = rb_enc_get(RMATCH(match)->str);
 821     if (rb_enc_mbmaxlen(enc) == 1) {
 822         for (i = 0; i < num_regs; i++) {
 823             rm->char_offset[i].beg = BEG(i);
 824             rm->char_offset[i].end = END(i);
 825         }
 826         rm->char_offset_updated = 1;
 827         return;
 828     }
 829
 830     pairs = ALLOCA_N(pair_t, num_regs*2);
 831     num_pos = 0;
 832     for (i = 0; i < num_regs; i++) {
 833         if (BEG(i) < 0)
 834             continue;
 835         pairs[num_pos++].byte_pos = BEG(i);
 836         pairs[num_pos++].byte_pos = END(i);
 837     }
 838     qsort(pairs, num_pos, sizeof(pair_t), pair_byte_cmp);
 839
 840     s = p = RSTRING_PTR(RMATCH(match)->str);
 841     e = s + RSTRING_LEN(RMATCH(match)->str);
 842     c = 0;
 843     for (i = 0; i < num_pos; i++) {
 844         q = s + pairs[i].byte_pos;
 845         c += rb_enc_strlen(p, q, enc);
 846         pairs[i].char_pos = c;
 847         p = q;
 848     }
 849
 850     for (i = 0; i < num_regs; i++) {
 851         pair_t key, *found;
 852         if (BEG(i) < 0) {
 853             rm->char_offset[i].beg = -1;
 854             rm->char_offset[i].end = -1;
 855             continue;
 856         }
 857
 858         key.byte_pos = BEG(i);
 859         found = bsearch(&key, pairs, num_pos, sizeof(pair_t), pair_byte_cmp);
 860         rm->char_offset[i].beg = found->char_pos;
 861
 862         key.byte_pos = END(i);
 863         found = bsearch(&key, pairs, num_pos, sizeof(pair_t), pair_byte_cmp);
 864         rm->char_offset[i].end = found->char_pos;
 865     }
 866
 867     rm->char_offset_updated = 1;
 868 }
 869
 870 static void
 871 match_check(VALUE match)
 872 {
 873     if (!RMATCH(match)->regexp) {
 874         rb_raise(rb_eTypeError, "uninitialized Match");
 875     }
 876 }
 877
 878 /* :nodoc: */
 879 static VALUE
 880 match_init_copy(VALUE obj, VALUE orig)
 881 {
 882     struct rmatch *rm;
 883
 884     if (obj == orig) return obj;
 885
 886     if (!rb_obj_is_instance_of(orig, rb_obj_class(obj))) {
 887         rb_raise(rb_eTypeError, "wrong argument class");
 888     }
 889     RMATCH(obj)->str = RMATCH(orig)->str;
 890     RMATCH(obj)->regexp = RMATCH(orig)->regexp;
 891
 892     rm = RMATCH(obj)->rmatch;
 893     onig_region_copy(&rm->regs, RMATCH_REGS(orig));
 894
 895     if (!RMATCH(orig)->rmatch->char_offset_updated) {
 896         rm->char_offset_updated = 0;
 897     }
 898     else {
 899         if (rm->char_offset_num_allocated < rm->regs.num_regs) {
 900             REALLOC_N(rm->char_offset, struct rmatch_offset, rm->regs.num_regs);
 901             rm->char_offset_num_allocated = rm->regs.num_regs;
 902         }
 903         MEMCPY(rm->char_offset, RMATCH(orig)->rmatch->char_offset,
 904                struct rmatch_offset, rm->regs.num_regs);
 905         rm->char_offset_updated = 1;
 906     }
 907
 908     return obj;
 909 }
 910
 911
 912 /*
 913  * call-seq:
 914  *    mtch.regexp   => regexp
 915  *
 916  * Returns the regexp.
 917  *
 918  *     m = /a.*b/.match("abc")
 919  *     m.regexp #=> /a.*b/
 920  */
 921
 922 static VALUE
 923 match_regexp(VALUE match)
 924 {
 925     match_check(match);
 926     return RMATCH(match)->regexp;
 927 }
 928
 929 /*
 930  * call-seq:
 931  *    mtch.names   => [name1, name2, ...]
 932  *
 933  * Returns a list of names of captures as an array of strings.
 934  * It is same as mtch.regexp.names.
 935  *
 936  *     /(?<foo>.)(?<bar>.)(?<baz>.)/.match("hoge").names
 937  *     #=> ["foo", "bar", "baz"]
 938  *
 939  *     m = /(?<x>.)(?<y>.)?/.match("a") #=> #<MatchData "a" x:"a" y:nil>
 940  *     m.names                          #=> ["x", "y"]
 941  */
 942
 943 static VALUE
 944 match_names(VALUE match)
 945 {
 946     match_check(match);
 947     return rb_reg_names(RMATCH(match)->regexp);
 948 }
 949
 950 /*
 951  *  call-seq:
 952  *     mtch.length   => integer
 953  *     mtch.size     => integer
 954  *
 955  *  Returns the number of elements in the match array.
 956  *
 957  *     m = /(.)(.)(\d+)(\d)/.match("THX1138.")
 958  *     m.length   #=> 5
 959  *     m.size     #=> 5
 960  */
 961
 962 static VALUE
 963 match_size(VALUE match)
 964 {
 965     match_check(match);
 966     return INT2FIX(RMATCH_REGS(match)->num_regs);
 967 }
 968
 969 static int
 970 match_backref_number(VALUE match, VALUE backref)
 971 {
 972     const char *name;
 973     int num;
 974
 975     struct re_registers *regs = RMATCH_REGS(match);
 976     VALUE regexp = RMATCH(match)->regexp;
 977
 978     match_check(match);
 979     switch(TYPE(backref)) {
 980       default:
 981         return NUM2INT(backref);
 982
 983       case T_SYMBOL:
 984         name = rb_id2name(SYM2ID(backref));
 985         break;
 986
 987       case T_STRING:
 988         name = StringValueCStr(backref);
 989         break;
 990     }
 991
 992     num = onig_name_to_backref_number(RREGEXP(regexp)->ptr,
 993               (const unsigned char*)name,
 994               (const unsigned char*)name + strlen(name),
 995               regs);
 996
 997     if (num < 1) {
 998         rb_raise(rb_eIndexError, "undefined group name reference: %s", name);
 999     }
1000
1001     return num;
1002 }
1003
1004
1005 /*
1006  *  call-seq:
1007  *     mtch.offset(n)   => array
1008  *
1009  *  Returns a two-element array containing the beginning and ending offsets of
1010  *  the <em>n</em>th match.
1011  *  <em>n</em> can be a string or symbol to reference a named capture.
1012  *
1013  *     m = /(.)(.)(\d+)(\d)/.match("THX1138.")
1014  *     m.offset(0)      #=> [1, 7]
1015  *     m.offset(4)      #=> [6, 7]
1016  *
1017  *     m = /(?<foo>.)(.)(?<bar>.)/.match("hoge")
1018  *     p m.offset(:foo) #=> [0, 1]
1019  *     p m.offset(:bar) #=> [2, 3]
1020  *
1021  */
1022
1023 static VALUE
1024 match_offset(VALUE match, VALUE n)
1025 {
1026     int i = match_backref_number(match, n);
1027     struct re_registers *regs = RMATCH_REGS(match);
1028
1029     match_check(match);
1030     if (i < 0 || regs->num_regs <= i)
1031         rb_raise(rb_eIndexError, "index %d out of matches", i);
1032
1033     if (BEG(i) < 0)
1034         return rb_assoc_new(Qnil, Qnil);
1035
1036     update_char_offset(match);
1037     return rb_assoc_new(INT2FIX(RMATCH(match)->rmatch->char_offset[i].beg),
1038                         INT2FIX(RMATCH(match)->rmatch->char_offset[i].end));
1039 }
1040
1041
1042 /*
1043  *  call-seq:
1044  *     mtch.begin(n)   => integer
1045  *
1046  *  Returns the offset of the start of the <em>n</em>th element of the match
1047  *  array in the string.
1048  *  <em>n</em> can be a string or symbol to reference a named capture.
1049  *
1050  *     m = /(.)(.)(\d+)(\d)/.match("THX1138.")
1051  *     m.begin(0)       #=> 1
1052  *     m.begin(2)       #=> 2
1053  *
1054  *     m = /(?<foo>.)(.)(?<bar>.)/.match("hoge")
1055  *     p m.begin(:foo)  #=> 0
1056  *     p m.begin(:bar)  #=> 2
1057  */
1058
1059 static VALUE
1060 match_begin(VALUE match, VALUE n)
1061 {
1062     int i = match_backref_number(match, n);
1063     struct re_registers *regs = RMATCH_REGS(match);
1064
1065     match_check(match);
1066     if (i < 0 || regs->num_regs <= i)
1067         rb_raise(rb_eIndexError, "index %d out of matches", i);
1068
1069     if (BEG(i) < 0)
1070         return Qnil;
1071
1072     update_char_offset(match);
1073     return INT2FIX(RMATCH(match)->rmatch->char_offset[i].beg);
1074 }
1075
1076
1077 /*
1078  *  call-seq:
1079  *     mtch.end(n)   => integer
1080  *
1081  *  Returns the offset of the character immediately following the end of the
1082  *  <em>n</em>th element of the match array in the string.
1083  *  <em>n</em> can be a string or symbol to reference a named capture.
1084  *
1085  *     m = /(.)(.)(\d+)(\d)/.match("THX1138.")
1086  *     m.end(0)         #=> 7
1087  *     m.end(2)         #=> 3
1088  *
1089  *     m = /(?<foo>.)(.)(?<bar>.)/.match("hoge")
1090  *     p m.end(:foo)    #=> 1
1091  *     p m.end(:bar)    #=> 3
1092  */
1093
1094 static VALUE
1095 match_end(VALUE match, VALUE n)
1096 {
1097     int i = match_backref_number(match, n);
1098     struct re_registers *regs = RMATCH_REGS(match);
1099
1100     match_check(match);
1101     if (i < 0 || regs->num_regs <= i)
1102         rb_raise(rb_eIndexError, "index %d out of matches", i);
1103
1104     if (BEG(i) < 0)
1105         return Qnil;
1106
1107     update_char_offset(match);
1108     return INT2FIX(RMATCH(match)->rmatch->char_offset[i].end);
1109 }
1110
1111 #define MATCH_BUSY FL_USER2
1112
1113 void
1114 rb_match_busy(VALUE match)
1115 {
1116     FL_SET(match, MATCH_BUSY);
1117 }
1118
1119 /*
1120  *  call-seq:
1121  *     rxp.fixed_encoding?   => true or false
1122  *
1123  *  Returns false if rxp is applicable to
1124  *  a string with any ASCII compatible encoding.
1125  *  Returns true otherwise.
1126  *
1127  *      r = /a/
1128  *      r.fixed_encoding?                               #=> false
1129  *      r =~ "\u{6666} a"                               #=> 2
1130  *      r =~ "\xa1\xa2 a".force_encoding("euc-jp")      #=> 2
1131  *      r =~ "abc".force_encoding("euc-jp")             #=> 0
1132  *
1133  *      r = /a/u
1134  *      r.fixed_encoding?                               #=> true
1135  *      r.encoding                                      #=> #<Encoding:UTF-8>
1136  *      r =~ "\u{6666} a"                               #=> 2
1137  *      r =~ "\xa1\xa2".force_encoding("euc-jp")        #=> ArgumentError
1138  *      r =~ "abc".force_encoding("euc-jp")             #=> 0
1139  *
1140  *      r = /\u{6666}/
1141  *      r.fixed_encoding?                               #=> true
1142  *      r.encoding                                      #=> #<Encoding:UTF-8>
1143  *      r =~ "\u{6666} a"                               #=> 0
1144  *      r =~ "\xa1\xa2".force_encoding("euc-jp")        #=> ArgumentError
1145  *      r =~ "abc".force_encoding("euc-jp")             #=> nil
1146  */
1147
1148 static VALUE
1149 rb_reg_fixed_encoding_p(VALUE re)
1150 {
1151     if (FL_TEST(re, KCODE_FIXED))
1152         return Qtrue;
1153     else
1154         return Qfalse;
1155 }
1156
1157 static VALUE
1158 rb_reg_preprocess(const char *p, const char *end, rb_encoding *enc,
1159         rb_encoding **fixed_enc, onig_errmsg_buffer err);
1160
1161
1162 static void
1163 reg_enc_error(VALUE re, VALUE str)
1164 {
1165     rb_raise(rb_eArgError,
1166              "incompatible encoding regexp match (%s regexp with %s string)",
1167              rb_enc_name(RREGEXP(re)->ptr->enc),
1168              rb_enc_name(rb_enc_get(str)));
1169 }
1170
1171 static rb_encoding*
1172 rb_reg_prepare_enc(VALUE re, VALUE str, int warn)
1173 {
1174     rb_encoding *enc = 0;
1175
1176     if (rb_enc_str_coderange(str) == ENC_CODERANGE_BROKEN) {
1177         rb_raise(rb_eArgError,
1178             "broken %s string",
1179             rb_enc_name(rb_enc_get(str)));
1180     }
1181
1182     rb_reg_check(re);
1183     enc = rb_enc_get(str);
1184     if (!rb_enc_str_asciicompat_p(str)) {
1185         if (RREGEXP(re)->ptr->enc != enc) {
1186             reg_enc_error(re, str);
1187         }
1188     }
1189     else if (rb_reg_fixed_encoding_p(re)) {
1190         if (RREGEXP(re)->ptr->enc != enc &&
1191             (!rb_enc_asciicompat(RREGEXP(re)->ptr->enc) ||
1192              rb_enc_str_coderange(str) != ENC_CODERANGE_7BIT)) {
1193             reg_enc_error(re, str);
1194         }
1195         enc = RREGEXP(re)->ptr->enc;
1196     }
1197     if (warn && (RBASIC(re)->flags & REG_ENCODING_NONE) &&
1198         enc != rb_ascii8bit_encoding() &&
1199         rb_enc_str_coderange(str) != ENC_CODERANGE_7BIT) {
1200         rb_warn("regexp match /.../n against to %s string",
1201                 rb_enc_name(enc));
1202     }
1203     return enc;
1204 }
1205
1206 regex_t *
1207 rb_reg_prepare_re(VALUE re, VALUE str)
1208 {
1209     regex_t *reg = RREGEXP(re)->ptr;
1210     onig_errmsg_buffer err = "";
1211     int r;
1212     OnigErrorInfo einfo;
1213     const char *pattern;
1214     VALUE unescaped;
1215     rb_encoding *fixed_enc = 0;
1216     rb_encoding *enc = rb_reg_prepare_enc(re, str, 1);
1217
1218     if (reg->enc == enc) return reg;
1219
1220     rb_reg_check(re);
1221     reg = RREGEXP(re)->ptr;
1222     pattern = RREGEXP_SRC_PTR(re);
1223
1224     unescaped = rb_reg_preprocess(
1225         pattern, pattern + RREGEXP_SRC_LEN(re), enc,
1226         &fixed_enc, err);
1227
1228     if (unescaped == Qnil) {
1229         rb_raise(rb_eArgError, "regexp preprocess failed: %s", err);
1230     }
1231
1232     r = onig_new(&reg, (UChar* )RSTRING_PTR(unescaped),
1233                  (UChar* )(RSTRING_PTR(unescaped) + RSTRING_LEN(unescaped)),
1234                  reg->options, enc,
1235                  OnigDefaultSyntax, &einfo);
1236     if (r) {
1237         onig_error_code_to_str((UChar*)err, r, &einfo);
1238         rb_reg_raise(pattern, RREGEXP_SRC_LEN(re), err, re);
1239     }
1240
1241     RB_GC_GUARD(unescaped);
1242     return reg;
1243 }
1244
1245 int
1246 rb_reg_adjust_startpos(VALUE re, VALUE str, int pos, int reverse)
1247 {
1248     int range;
1249     rb_encoding *enc;
1250     UChar *p, *string;
1251
1252     enc = rb_reg_prepare_enc(re, str, 0);
1253
1254     if (reverse) {
1255         range = -pos;
1256     }
1257     else {
1258         range = RSTRING_LEN(str) - pos;
1259     }
1260
1261     if (pos > 0 && ONIGENC_MBC_MAXLEN(enc) != 1 && pos < RSTRING_LEN(str)) {
1262          string = (UChar*)RSTRING_PTR(str);
1263
1264          if (range > 0) {
1265               p = onigenc_get_right_adjust_char_head(enc, string, string + pos);
1266          }
1267          else {
1268               p = ONIGENC_LEFT_ADJUST_CHAR_HEAD(enc, string, string + pos);
1269          }
1270          return p - string;
1271     }
1272
1273     return pos;
1274 }
1275
1276 int
1277 rb_reg_search(VALUE re, VALUE str, int pos, int reverse)
1278 {
1279     int result;
1280     VALUE match;
1281     struct re_registers regi, *regs = &regi;
1282     char *range = RSTRING_PTR(str);
1283     regex_t *reg;
1284     int tmpreg;
1285
1286     if (pos > RSTRING_LEN(str) || pos < 0) {
1287         rb_backref_set(Qnil);
1288         return -1;
1289     }
1290
1291     reg = rb_reg_prepare_re(re, str);
1292     tmpreg = reg != RREGEXP(re)->ptr;
1293     if (!tmpreg) RREGEXP(re)->usecnt++;
1294
1295     match = rb_backref_get();
1296     if (!NIL_P(match)) {
1297         if (FL_TEST(match, MATCH_BUSY)) {
1298             match = Qnil;
1299         }
1300         else {
1301             regs = RMATCH_REGS(match);
1302         }
1303     }
1304     if (NIL_P(match)) {
1305         MEMZERO(regs, struct re_registers, 1);
1306     }
1307     if (!reverse) {
1308         range += RSTRING_LEN(str);
1309     }
1310     result = onig_search(reg,
1311                          (UChar*)(RSTRING_PTR(str)),
1312                          ((UChar*)(RSTRING_PTR(str)) + RSTRING_LEN(str)),
1313                          ((UChar*)(RSTRING_PTR(str)) + pos),
1314                          ((UChar*)range),
1315                          regs, ONIG_OPTION_NONE);
1316     if (!tmpreg) RREGEXP(re)->usecnt--;
1317     if (tmpreg) {
1318         if (RREGEXP(re)->usecnt) {
1319             onig_free(reg);
1320         }
1321         else {
1322             onig_free(RREGEXP(re)->ptr);
1323             RREGEXP(re)->ptr = reg;
1324         }
1325     }
1326     if (result < 0) {
1327         if (regs == &regi)
1328             onig_region_free(regs, 0);
1329         if (result == ONIG_MISMATCH) {
1330             rb_backref_set(Qnil);
1331             return result;
1332         }
1333         else {
1334             onig_errmsg_buffer err = "";
1335             onig_error_code_to_str((UChar*)err, result);
1336             rb_reg_raise(RREGEXP_SRC_PTR(re), RREGEXP_SRC_LEN(re), err, 0);
1337         }
1338     }
1339
1340     if (NIL_P(match)) {
1341         match = match_alloc(rb_cMatch);
1342         onig_region_copy(RMATCH_REGS(match), regs);
1343         onig_region_free(regs, 0);
1344     }
1345     else {
1346         if (rb_safe_level() >= 3)
1347             OBJ_TAINT(match);
1348         else
1349             FL_UNSET(match, FL_TAINT);
1350     }
1351
1352     RMATCH(match)->str = rb_str_new4(str);
1353     RMATCH(match)->regexp = re;
1354     RMATCH(match)->rmatch->char_offset_updated = 0;
1355     rb_backref_set(match);
1356
1357     OBJ_INFECT(match, re);
1358     OBJ_INFECT(match, str);
1359
1360     return result;
1361 }
1362
1363 VALUE
1364 rb_reg_nth_defined(int nth, VALUE match)
1365 {
1366     struct re_registers *regs;
1367     if (NIL_P(match)) return Qnil;
1368     match_check(match);
1369     regs = RMATCH_REGS(match);
1370     if (nth >= regs->num_regs) {
1371         return Qnil;
1372     }
1373     if (nth < 0) {
1374         nth += regs->num_regs;
1375         if (nth <= 0) return Qnil;
1376     }
1377     if (BEG(nth) == -1) return Qfalse;
1378     return Qtrue;
1379 }
1380
1381 VALUE
1382 rb_reg_nth_match(int nth, VALUE match)
1383 {
1384     VALUE str;
1385     long start, end, len;
1386     struct re_registers *regs;
1387
1388     if (NIL_P(match)) return Qnil;
1389     match_check(match);
1390     regs = RMATCH_REGS(match);
1391     if (nth >= regs->num_regs) {
1392         return Qnil;
1393     }
1394     if (nth < 0) {
1395         nth += regs->num_regs;
1396         if (nth <= 0) return Qnil;
1397     }
1398     start = BEG(nth);
1399     if (start == -1) return Qnil;
1400     end = END(nth);
1401     len = end - start;
1402     str = rb_str_subseq(RMATCH(match)->str, start, len);
1403     OBJ_INFECT(str, match);
1404     return str;
1405 }
1406
1407 VALUE
1408 rb_reg_last_match(VALUE match)
1409 {
1410     return rb_reg_nth_match(0, match);
1411 }
1412
1413
1414 /*
1415  *  call-seq:
1416  *     mtch.pre_match   => str
1417  *
1418  *  Returns the portion of the original string before the current match.
1419  *  Equivalent to the special variable <code>$`</code>.
1420  *
1421  *     m = /(.)(.)(\d+)(\d)/.match("THX1138.")
1422  *     m.pre_match   #=> "T"
1423  */
1424
1425 VALUE
1426 rb_reg_match_pre(VALUE match)
1427 {
1428     VALUE str;
1429     struct re_registers *regs;
1430
1431     if (NIL_P(match)) return Qnil;
1432     match_check(match);
1433     regs = RMATCH_REGS(match);
1434     if (BEG(0) == -1) return Qnil;
1435     str = rb_str_subseq(RMATCH(match)->str, 0, BEG(0));
1436     if (OBJ_TAINTED(match)) OBJ_TAINT(str);
1437     return str;
1438 }
1439
1440
1441 /*
1442  *  call-seq:
1443  *     mtch.post_match   => str
1444  *
1445  *  Returns the portion of the original string after the current match.
1446  *  Equivalent to the special variable <code>$'</code>.
1447  *
1448  *     m = /(.)(.)(\d+)(\d)/.match("THX1138: The Movie")
1449  *     m.post_match   #=> ": The Movie"
1450  */
1451
1452 VALUE
1453 rb_reg_match_post(VALUE match)
1454 {
1455     VALUE str;
1456     long pos;
1457     struct re_registers *regs;
1458
1459     if (NIL_P(match)) return Qnil;
1460     match_check(match);
1461     regs = RMATCH_REGS(match);
1462     if (BEG(0) == -1) return Qnil;
1463     str = RMATCH(match)->str;
1464     pos = END(0);
1465     str = rb_str_subseq(str, pos, RSTRING_LEN(str) - pos);
1466     if (OBJ_TAINTED(match)) OBJ_TAINT(str);
1467     return str;
1468 }
1469
1470 VALUE
1471 rb_reg_match_last(VALUE match)
1472 {
1473     int i;
1474     struct re_registers *regs;
1475
1476     if (NIL_P(match)) return Qnil;
1477     match_check(match);
1478     regs = RMATCH_REGS(match);
1479     if (BEG(0) == -1) return Qnil;
1480
1481     for (i=regs->num_regs-1; BEG(i) == -1 && i > 0; i--)
1482         ;
1483     if (i == 0) return Qnil;
1484     return rb_reg_nth_match(i, match);
1485 }
1486
1487 static VALUE
1488 last_match_getter(void)
1489 {
1490     return rb_reg_last_match(rb_backref_get());
1491 }
1492
1493 static VALUE
1494 prematch_getter(void)
1495 {
1496     return rb_reg_match_pre(rb_backref_get());
1497 }
1498
1499 static VALUE
1500 postmatch_getter(void)
1501 {
1502     return rb_reg_match_post(rb_backref_get());
1503 }
1504
1505 static VALUE
1506 last_paren_match_getter(void)
1507 {
1508     return rb_reg_match_last(rb_backref_get());
1509 }
1510
1511 static VALUE
1512 match_array(VALUE match, int start)
1513 {
1514     struct re_registers *regs = RMATCH_REGS(match);
1515     VALUE ary = rb_ary_new2(regs->num_regs);
1516     VALUE target = RMATCH(match)->str;
1517     int i;
1518     int taint = OBJ_TAINTED(match);
1519
1520     match_check(match);
1521     for (i=start; i<regs->num_regs; i++) {
1522         if (regs->beg[i] == -1) {
1523             rb_ary_push(ary, Qnil);
1524         }
1525         else {
1526             VALUE str = rb_str_subseq(target, regs->beg[i], regs->end[i]-regs->beg[i]);
1527             if (taint) OBJ_TAINT(str);
1528             rb_ary_push(ary, str);
1529         }
1530     }
1531     return ary;
1532 }
1533
1534
1535 /* [MG]:FIXME: I put parens around the /.../.match() in the first line of the
1536    second example to prevent the '*' followed by a '/' from ending the
1537    comment. */
1538
1539 /*
1540  *  call-seq:
1541  *     mtch.to_a   => anArray
1542  *
1543  *  Returns the array of matches.
1544  *
1545  *     m = /(.)(.)(\d+)(\d)/.match("THX1138.")
1546  *     m.to_a   #=> ["HX1138", "H", "X", "113", "8"]
1547  *
1548  *  Because <code>to_a</code> is called when expanding
1549  *  <code>*</code><em>variable</em>, there's a useful assignment
1550  *  shortcut for extracting matched fields. This is slightly slower than
1551  *  accessing the fields directly (as an intermediate array is
1552  *  generated).
1553  *
1554  *     all,f1,f2,f3 = *(/(.)(.)(\d+)(\d)/.match("THX1138."))
1555  *     all   #=> "HX1138"
1556  *     f1    #=> "H"
1557  *     f2    #=> "X"
1558  *     f3    #=> "113"
1559  */
1560
1561 static VALUE
1562 match_to_a(VALUE match)
1563 {
1564     return match_array(match, 0);
1565 }
1566
1567
1568 /*
1569  *  call-seq:
1570  *     mtch.captures   => array
1571  *
1572  *  Returns the array of captures; equivalent to <code>mtch.to_a[1..-1]</code>.
1573  *
1574  *     f1,f2,f3,f4 = /(.)(.)(\d+)(\d)/.match("THX1138.").captures
1575  *     f1    #=> "H"
1576  *     f2    #=> "X"
1577  *     f3    #=> "113"
1578  *     f4    #=> "8"
1579  */
1580 static VALUE
1581 match_captures(VALUE match)
1582 {
1583     return match_array(match, 1);
1584 }
1585
1586 static int
1587 name_to_backref_number(struct re_registers *regs, VALUE regexp, const char* name, const char* name_end)
1588 {
1589     int num;
1590
1591     num = onig_name_to_backref_number(RREGEXP(regexp)->ptr,
1592         (const unsigned char* )name, (const unsigned char* )name_end, regs);
1593     if (num >= 1) {
1594         return num;
1595     }
1596     else {
1597         VALUE s = rb_str_new(name, (long )(name_end - name));
1598         rb_raise(rb_eIndexError, "undefined group name reference: %s",
1599                                  StringValuePtr(s));
1600     }
1601 }
1602
1603 /*
1604  *  call-seq:
1605  *     mtch[i]               => str or nil
1606  *     mtch[start, length]   => array
1607  *     mtch[range]           => array
1608  *     mtch[name]            => str or nil
1609  *
1610  *  Match Reference---<code>MatchData</code> acts as an array, and may be
1611  *  accessed using the normal array indexing techniques.  <i>mtch</i>[0] is
1612  *  equivalent to the special variable <code>$&</code>, and returns the entire
1613  *  matched string.  <i>mtch</i>[1], <i>mtch</i>[2], and so on return the values
1614  *  of the matched backreferences (portions of the pattern between parentheses).
1615  *
1616  *     m = /(.)(.)(\d+)(\d)/.match("THX1138.")
1617  *     m          #=> #<MatchData "HX1138" 1:"H" 2:"X" 3:"113" 4:"8">
1618  *     m[0]       #=> "HX1138"
1619  *     m[1, 2]    #=> ["H", "X"]
1620  *     m[1..3]    #=> ["H", "X", "113"]
1621  *     m[-3, 2]   #=> ["X", "113"]
1622  *
1623  *     m = /(?<foo>a+)b/.match("ccaaab")
1624  *     m          #=> #<MatchData "aaab" foo:"aaa">
1625  *     m["foo"]   #=> "aaa"
1626  *     m[:foo]    #=> "aaa"
1627  */
1628
1629 static VALUE
1630 match_aref(int argc, VALUE *argv, VALUE match)
1631 {
1632     VALUE idx, rest;
1633
1634     match_check(match);
1635     rb_scan_args(argc, argv, "11", &idx, &rest);
1636
1637     if (NIL_P(rest)) {
1638       if (FIXNUM_P(idx)) {
1639         if (FIX2INT(idx) >= 0) {
1640           return rb_reg_nth_match(FIX2INT(idx), match);
1641         }
1642       }
1643       else {
1644         const char *p;
1645         int num;
1646
1647         switch (TYPE(idx)) {
1648           case T_SYMBOL:
1649             p = rb_id2name(SYM2ID(idx));
1650             goto name_to_backref;
1651             break;
1652           case T_STRING:
1653             p = StringValuePtr(idx);
1654
1655           name_to_backref:
1656             num = name_to_backref_number(RMATCH_REGS(match),
1657                        RMATCH(match)->regexp, p, p + strlen(p));
1658             return rb_reg_nth_match(num, match);
1659             break;
1660
1661           default:
1662             break;
1663         }
1664       }
1665     }
1666
1667     return rb_ary_aref(argc, argv, match_to_a(match));
1668 }
1669
1670 static VALUE
1671 match_entry(VALUE match, long n)
1672 {
1673     return rb_reg_nth_match(n, match);
1674 }
1675
1676
1677 /*
1678  *  call-seq:
1679  *
1680  *     mtch.values_at([index]*)   => array
1681  *
1682  *  Uses each <i>index</i> to access the matching values, returning an array of
1683  *  the corresponding matches.
1684  *
1685  *     m = /(.)(.)(\d+)(\d)/.match("THX1138: The Movie")
1686  *     m.to_a               #=> ["HX1138", "H", "X", "113", "8"]
1687  *     m.values_at(0, 2, -2)   #=> ["HX1138", "X", "113"]
1688  */
1689
1690 static VALUE
1691 match_values_at(int argc, VALUE *argv, VALUE match)
1692 {
1693     struct re_registers *regs = RMATCH_REGS(match);
1694     match_check(match);
1695     return rb_get_values_at(match, regs->num_regs, argc, argv, match_entry);
1696 }
1697
1698
1699 /*
1700  *  call-seq:
1701  *     mtch.to_s   => str
1702  *
1703  *  Returns the entire matched string.
1704  *
1705  *     m = /(.)(.)(\d+)(\d)/.match("THX1138.")
1706  *     m.to_s   #=> "HX1138"
1707  */
1708
1709 static VALUE
1710 match_to_s(VALUE match)
1711 {
1712     VALUE str = rb_reg_last_match(match);
1713
1714     match_check(match);
1715     if (NIL_P(str)) str = rb_str_new(0,0);
1716     if (OBJ_TAINTED(match)) OBJ_TAINT(str);
1717     if (OBJ_TAINTED(RMATCH(match)->str)) OBJ_TAINT(str);
1718     return str;
1719 }
1720
1721
1722 /*
1723  *  call-seq:
1724  *     mtch.string   => str
1725  *
1726  *  Returns a frozen copy of the string passed in to <code>match</code>.
1727  *
1728  *     m = /(.)(.)(\d+)(\d)/.match("THX1138.")
1729  *     m.string   #=> "THX1138."
1730  */
1731
1732 static VALUE
1733 match_string(VALUE match)
1734 {
1735     match_check(match);
1736     return RMATCH(match)->str;  /* str is frozen */
1737 }
1738
1739 struct backref_name_tag {
1740     const UChar *name;
1741     long len;
1742 };
1743
1744 static int
1745 match_inspect_name_iter(const OnigUChar *name, const OnigUChar *name_end,
1746           int back_num, int *back_refs, OnigRegex regex, void *arg0)
1747 {
1748     struct backref_name_tag *arg = (struct backref_name_tag *)arg0;
1749     int i;
1750
1751     for (i = 0; i < back_num; i++) {
1752         arg[back_refs[i]].name = name;
1753         arg[back_refs[i]].len = name_end - name;
1754     }
1755     return 0;
1756 }
1757
1758 /*
1759  * call-seq:
1760  *    mtch.inspect   => str
1761  *
1762  * Returns a printable version of <i>mtch</i>.
1763  *
1764  *     puts /.$/.match("foo").inspect
1765  *     #=> #<MatchData "o">
1766  *
1767  *     puts /(.)(.)(.)/.match("foo").inspect
1768  *     #=> #<MatchData "foo" 1:"f" 2:"o" 3:"o">
1769  *
1770  *     puts /(.)(.)?(.)/.match("fo").inspect
1771  *     #=> #<MatchData "fo" 1:"f" 2:nil 3:"o">
1772  *
1773  *     puts /(?<foo>.)(?<bar>.)(?<baz>.)/.match("hoge").inspect
1774  *     #=> #<MatchData "hog" foo:"h" bar:"o" baz:"g">
1775  *
1776  */
1777
1778 static VALUE
1779 match_inspect(VALUE match)
1780 {
1781     const char *cname = rb_obj_classname(match);
1782     VALUE str;
1783     int i;
1784     struct re_registers *regs = RMATCH_REGS(match);
1785     int num_regs = regs->num_regs;
1786     struct backref_name_tag *names;
1787     VALUE regexp = RMATCH(match)->regexp;
1788
1789     if (regexp == 0) {
1790         return rb_sprintf("#<%s:%p>", cname, (void*)match);
1791     }
1792
1793     names = ALLOCA_N(struct backref_name_tag, num_regs);
1794     MEMZERO(names, struct backref_name_tag, num_regs);
1795
1796     onig_foreach_name(RREGEXP(regexp)->ptr,
1797             match_inspect_name_iter, names);
1798
1799     str = rb_str_buf_new2("#<");
1800     rb_str_buf_cat2(str, cname);
1801
1802     for (i = 0; i < num_regs; i++) {
1803         VALUE v;
1804         rb_str_buf_cat2(str, " ");
1805         if (0 < i) {
1806             if (names[i].name)
1807                 rb_str_buf_cat(str, (const char *)names[i].name, names[i].len);
1808             else {
1809                 rb_str_catf(str, "%d", i);
1810             }
1811             rb_str_buf_cat2(str, ":");
1812         }
1813         v = rb_reg_nth_match(i, match);
1814         if (v == Qnil)
1815             rb_str_buf_cat2(str, "nil");
1816         else
1817             rb_str_buf_append(str, rb_str_inspect(v));
1818     }
1819     rb_str_buf_cat2(str, ">");
1820
1821     return str;
1822 }
1823
1824 VALUE rb_cRegexp;
1825
1826 static int
1827 read_escaped_byte(const char **pp, const char *end, onig_errmsg_buffer err)
1828 {
1829     const char *p = *pp;
1830     int code;
1831     int meta_prefix = 0, ctrl_prefix = 0;
1832     int len;
1833     int retbyte;
1834
1835     retbyte = -1;
1836     if (p == end || *p++ != '\\') {
1837         strcpy(err, "too short escaped multibyte character");
1838         return -1;
1839     }
1840
1841 again:
1842     if (p == end) {
1843         strcpy(err, "too short escape sequence");
1844         return -1;
1845     }
1846     switch (*p++) {
1847       case '\\': code = '\\'; break;
1848       case 'n': code = '\n'; break;
1849       case 't': code = '\t'; break;
1850       case 'r': code = '\r'; break;
1851       case 'f': code = '\f'; break;
1852       case 'v': code = '\013'; break;
1853       case 'a': code = '\007'; break;
1854       case 'e': code = '\033'; break;
1855
1856       /* \OOO */
1857       case '0': case '1': case '2': case '3':
1858       case '4': case '5': case '6': case '7':
1859         p--;
1860         code = ruby_scan_oct(p, end < p+3 ? end-p : 3, &len);
1861         p += len;
1862         break;
1863
1864       case 'x': /* \xHH */
1865         code = ruby_scan_hex(p, end < p+2 ? end-p : 2, &len);
1866         if (len < 1) {
1867             strcpy(err, "invalid hex escape");
1868             return -1;
1869         }
1870         p += len;
1871         break;
1872
1873       case 'M': /* \M-X, \M-\C-X, \M-\cX */
1874         if (meta_prefix) {
1875             strcpy(err, "duplicate meta escape");
1876             return -1;
1877         }
1878         meta_prefix = 1;
1879         if (p+1 < end && *p++ == '-' && (*p & 0x80) == 0) {
1880             if (*p == '\\') {
1881                 p++;
1882                 goto again;
1883             }
1884             else {
1885                 code = *p++;
1886                 break;
1887             }
1888         }
1889         strcpy(err, "too short meta escape");
1890         return -1;
1891
1892       case 'C': /* \C-X, \C-\M-X */
1893         if (p == end || *p++ != '-') {
1894             strcpy(err, "too short control escape");
1895             return -1;
1896         }
1897       case 'c': /* \cX, \c\M-X */
1898         if (ctrl_prefix) {
1899             strcpy(err, "duplicate control escape");
1900             return -1;
1901         }
1902         ctrl_prefix = 1;
1903         if (p < end && (*p & 0x80) == 0) {
1904             if (*p == '\\') {
1905                 p++;
1906                 goto again;
1907             }
1908             else {
1909                 code = *p++;
1910                 break;
1911             }
1912         }
1913         strcpy(err, "too short control escape");
1914         return -1;
1915
1916       default:
1917         strcpy(err, "unexpected escape sequence");
1918         return -1;
1919     }
1920     if (code < 0 || 0xff < code) {
1921         strcpy(err, "invalid escape code");
1922         return -1;
1923     }
1924
1925     if (ctrl_prefix)
1926         code &= 0x1f;
1927     if (meta_prefix)
1928         code |= 0x80;
1929
1930     *pp = p;
1931     return code;
1932 }
1933
1934 static int
1935 unescape_escaped_nonascii(const char **pp, const char *end, rb_encoding *enc,
1936         VALUE buf, rb_encoding **encp, onig_errmsg_buffer err)
1937 {
1938     const char *p = *pp;
1939     int chmaxlen = rb_enc_mbmaxlen(enc);
1940     char *chbuf = ALLOCA_N(char, chmaxlen);
1941     int chlen = 0;
1942     int byte;
1943     int l;
1944
1945     memset(chbuf, 0, chmaxlen);
1946
1947     byte = read_escaped_byte(&p, end, err);
1948     if (byte == -1) {
1949         return -1;
1950     }
1951
1952     chbuf[chlen++] = byte;
1953     while (chlen < chmaxlen &&
1954            MBCLEN_NEEDMORE_P(rb_enc_precise_mbclen(chbuf, chbuf+chlen, enc))) {
1955         byte = read_escaped_byte(&p, end, err);
1956         if (byte == -1) {
1957             return -1;
1958         }
1959         chbuf[chlen++] = byte;
1960     }
1961
1962     l = rb_enc_precise_mbclen(chbuf, chbuf+chlen, enc);
1963     if (MBCLEN_INVALID_P(l)) {
1964         strcpy(err, "invalid multibyte escape");
1965         return -1;
1966     }
1967     if (1 < chlen || (chbuf[0] & 0x80)) {
1968         rb_str_buf_cat(buf, chbuf, chlen);
1969
1970         if (*encp == 0)
1971             *encp = enc;
1972         else if (*encp != enc) {
1973             strcpy(err, "escaped non ASCII character in UTF-8 regexp");
1974             return -1;
1975         }
1976     }
1977     else {
1978         char escbuf[5];
1979         snprintf(escbuf, sizeof(escbuf), "\\x%02X", chbuf[0]&0xff);
1980         rb_str_buf_cat(buf, escbuf, 4);
1981     }
1982     *pp = p;
1983     return 0;
1984 }
1985
1986 static int
1987 check_unicode_range(unsigned long code, onig_errmsg_buffer err)
1988 {
1989     if ((0xd800 <= code && code <= 0xdfff) || /* Surrogates */
1990         0x10ffff < code) {
1991         strcpy(err, "invalid Unicode range");
1992         return -1;
1993     }
1994     return 0;
1995 }
1996
1997 static int
1998 append_utf8(unsigned long uv,
1999         VALUE buf, rb_encoding **encp, onig_errmsg_buffer err)
2000 {
2001     if (check_unicode_range(uv, err) != 0)
2002         return -1;
2003     if (uv < 0x80) {
2004         char escbuf[5];
2005         snprintf(escbuf, sizeof(escbuf), "\\x%02X", (int)uv);
2006         rb_str_buf_cat(buf, escbuf, 4);
2007     }
2008     else {
2009         int len;
2010         char utf8buf[6];
2011         len = rb_uv_to_utf8(utf8buf, uv);
2012         rb_str_buf_cat(buf, utf8buf, len);
2013
2014         if (*encp == 0)
2015             *encp = rb_utf8_encoding();
2016         else if (*encp != rb_utf8_encoding()) {
2017             strcpy(err, "UTF-8 character in non UTF-8 regexp");
2018             return -1;
2019         }
2020     }
2021     return 0;
2022 }
2023
2024 static int
2025 unescape_unicode_list(const char **pp, const char *end,
2026         VALUE buf, rb_encoding **encp, onig_errmsg_buffer err)
2027 {
2028     const char *p = *pp;
2029     int has_unicode = 0;
2030     unsigned long code;
2031     int len;
2032
2033     while (p < end && ISSPACE(*p)) p++;
2034
2035     while (1) {
2036         code = ruby_scan_hex(p, end-p, &len);
2037         if (len == 0)
2038             break;
2039         if (6 < len) { /* max 10FFFF */
2040             strcpy(err, "invalid Unicode range");
2041             return -1;
2042         }
2043         p += len;
2044         if (append_utf8(code, buf, encp, err) != 0)
2045             return -1;
2046         has_unicode = 1;
2047
2048         while (p < end && ISSPACE(*p)) p++;
2049     }
2050
2051     if (has_unicode == 0) {
2052         strcpy(err, "invalid Unicode list");
2053         return -1;
2054     }
2055
2056     *pp = p;
2057
2058     return 0;
2059 }
2060
2061 static int
2062 unescape_unicode_bmp(const char **pp, const char *end,
2063         VALUE buf, rb_encoding **encp, onig_errmsg_buffer err)
2064 {
2065     const char *p = *pp;
2066     int len;
2067     unsigned long code;
2068
2069     if (end < p+4) {
2070         strcpy(err, "invalid Unicode escape");
2071         return -1;
2072     }
2073     code = ruby_scan_hex(p, 4, &len);
2074     if (len != 4) {
2075         strcpy(err, "invalid Unicode escape");
2076         return -1;
2077     }
2078     if (append_utf8(code, buf, encp, err) != 0)
2079         return -1;
2080     *pp = p + 4;
2081     return 0;
2082 }
2083
2084 static int
2085 unescape_nonascii(const char *p, const char *end, rb_encoding *enc,
2086         VALUE buf, rb_encoding **encp, int *has_property,
2087         onig_errmsg_buffer err)
2088 {
2089     char c;
2090     char smallbuf[2];
2091
2092     while (p < end) {
2093         int chlen = rb_enc_precise_mbclen(p, end, enc);
2094         if (!MBCLEN_CHARFOUND_P(chlen)) {
2095             strcpy(err, "invalid multibyte character");
2096             return -1;
2097         }
2098         chlen = MBCLEN_CHARFOUND_LEN(chlen);
2099         if (1 < chlen || (*p & 0x80)) {
2100             rb_str_buf_cat(buf, p, chlen);
2101             p += chlen;
2102             if (*encp == 0)
2103                 *encp = enc;
2104             else if (*encp != enc) {
2105                 strcpy(err, "non ASCII character in UTF-8 regexp");
2106                 return -1;
2107             }
2108             continue;
2109         }
2110
2111         switch (c = *p++) {
2112           case '\\':
2113             if (p == end) {
2114                 strcpy(err, "too short escape sequence");
2115                 return -1;
2116             }
2117             switch (c = *p++) {
2118               case '1': case '2': case '3':
2119               case '4': case '5': case '6': case '7': /* \O, \OO, \OOO or backref */
2120                 {
2121                     int octlen;
2122                     if (ruby_scan_oct(p-1, end-(p-1), &octlen) <= 0177) {
2123                         /* backref or 7bit octal.
2124                            no need to unescape anyway.
2125                            re-escaping may break backref */
2126                         goto escape_asis;
2127                     }
2128                 }
2129                 /* xxx: How about more than 199 subexpressions? */
2130
2131               case '0': /* \0, \0O, \0OO */
2132
2133               case 'x': /* \xHH */
2134               case 'c': /* \cX, \c\M-X */
2135               case 'C': /* \C-X, \C-\M-X */
2136               case 'M': /* \M-X, \M-\C-X, \M-\cX */
2137                 p = p-2;
2138                 if (unescape_escaped_nonascii(&p, end, enc, buf, encp, err) != 0)
2139                     return -1;
2140                 break;
2141
2142               case 'u':
2143                 if (p == end) {
2144                     strcpy(err, "too short escape sequence");
2145                     return -1;
2146                 }
2147                 if (*p == '{') {
2148                     /* \u{H HH HHH HHHH HHHHH HHHHHH ...} */
2149                     p++;
2150                     if (unescape_unicode_list(&p, end, buf, encp, err) != 0)
2151                         return -1;
2152                     if (p == end || *p++ != '}') {
2153                         strcpy(err, "invalid Unicode list");
2154                         return -1;
2155                     }
2156                     break;
2157                 }
2158                 else {
2159                     /* \uHHHH */
2160                     if (unescape_unicode_bmp(&p, end, buf, encp, err) != 0)
2161                         return -1;
2162                     break;
2163                 }
2164
2165               case 'p': /* \p{Hiragana} */
2166                 if (!*encp) {
2167                     *has_property = 1;
2168                 }
2169                 goto escape_asis;
2170
2171               default: /* \n, \\, \d, \9, etc. */
2172 escape_asis:
2173                 smallbuf[0] = '\\';
2174                 smallbuf[1] = c;
2175                 rb_str_buf_cat(buf, smallbuf, 2);
2176                 break;
2177             }
2178             break;
2179
2180           default:
2181             rb_str_buf_cat(buf, &c, 1);
2182             break;
2183         }
2184     }
2185
2186     return 0;
2187 }
2188
2189 static VALUE
2190 rb_reg_preprocess(const char *p, const char *end, rb_encoding *enc,
2191         rb_encoding **fixed_enc, onig_errmsg_buffer err)
2192 {
2193     VALUE buf;
2194     int has_property = 0;
2195
2196     buf = rb_str_buf_new(0);
2197
2198     if (rb_enc_asciicompat(enc))
2199         *fixed_enc = 0;
2200     else {
2201         *fixed_enc = enc;
2202         rb_enc_associate(buf, enc);
2203     }
2204
2205     if (unescape_nonascii(p, end, enc, buf, fixed_enc, &has_property, err) != 0)
2206         return Qnil;
2207
2208     if (has_property && !*fixed_enc) {
2209         *fixed_enc = enc;
2210     }
2211
2212     if (*fixed_enc) {
2213         rb_enc_associate(buf, *fixed_enc);
2214     }
2215
2216     return buf;
2217 }
2218
2219 VALUE
2220 rb_reg_check_preprocess(VALUE str)
2221 {
2222     rb_encoding *fixed_enc = 0;
2223     onig_errmsg_buffer err = "";
2224     VALUE buf;
2225     char *p, *end;
2226     rb_encoding *enc;
2227
2228     StringValue(str);
2229     p = RSTRING_PTR(str);
2230     end = p + RSTRING_LEN(str);
2231     enc = rb_enc_get(str);
2232
2233     buf = rb_reg_preprocess(p, end, enc, &fixed_enc, err);
2234     RB_GC_GUARD(str);
2235
2236     if (buf == Qnil) {
2237         return rb_reg_error_desc(str, 0, err);
2238     }
2239     return Qnil;
2240 }
2241
2242 static VALUE
2243 rb_reg_preprocess_dregexp(VALUE ary)
2244 {
2245     rb_encoding *fixed_enc = 0;
2246     rb_encoding *regexp_enc = 0;
2247     onig_errmsg_buffer err = "";
2248     int i;
2249     VALUE result = 0;
2250     int argc = RARRAY_LEN(ary);
2251     VALUE *argv = RARRAY_PTR(ary);
2252
2253     if (argc == 0) {
2254         rb_raise(rb_eArgError, "no arguments given");
2255     }
2256
2257     for (i = 0; i < argc; i++) {
2258         VALUE str = argv[i];
2259         VALUE buf;
2260         char *p, *end;
2261         rb_encoding *src_enc;
2262
2263         StringValue(str);
2264         p = RSTRING_PTR(str);
2265         end = p + RSTRING_LEN(str);
2266         src_enc = rb_enc_get(str);
2267
2268         buf = rb_reg_preprocess(p, end, src_enc, &fixed_enc, err);
2269
2270         if (buf == Qnil)
2271             rb_raise(rb_eArgError, "%s", err);
2272
2273         if (fixed_enc != 0) {
2274             if (regexp_enc != 0 && regexp_enc != fixed_enc) {
2275                 rb_raise(rb_eArgError, "encoding mismatch in dynamic regexp : %s and %s",
2276                          rb_enc_name(regexp_enc), rb_enc_name(fixed_enc));
2277             }
2278             regexp_enc = fixed_enc;
2279         }
2280
2281         if (!result)
2282             result = rb_str_new3(str);
2283         else
2284             rb_str_buf_append(result, str);
2285     }
2286     if (regexp_enc) {
2287         rb_enc_associate(result, regexp_enc);
2288     }
2289
2290     return result;
2291 }
2292
2293 static int
2294 rb_reg_initialize(VALUE obj, const char *s, int len, rb_encoding *enc,
2295                   int options, onig_errmsg_buffer err)
2296 {
2297     struct RRegexp *re = RREGEXP(obj);
2298     VALUE unescaped;
2299     rb_encoding *fixed_enc = 0;
2300     rb_encoding *a_enc = rb_ascii8bit_encoding();
2301
2302     if (!OBJ_UNTRUSTED(obj) && rb_safe_level() >= 4)
2303         rb_raise(rb_eSecurityError, "Insecure: can't modify regexp");
2304     rb_check_frozen(obj);
2305     if (FL_TEST(obj, REG_LITERAL))
2306         rb_raise(rb_eSecurityError, "can't modify literal regexp");
2307     if (re->ptr)
2308         rb_raise(rb_eTypeError, "already initialized regexp");
2309     re->ptr = 0;
2310
2311     unescaped = rb_reg_preprocess(s, s+len, enc, &fixed_enc, err);
2312     if (unescaped == Qnil)
2313         return -1;
2314
2315     if (fixed_enc) {
2316         if ((fixed_enc != enc && (options & ARG_ENCODING_FIXED)) ||
2317             (fixed_enc != a_enc && (options & ARG_ENCODING_NONE))) {
2318             strcpy(err, "incompatible character encoding");
2319             return -1;
2320         }
2321         if (fixed_enc != a_enc) {
2322             options |= ARG_ENCODING_FIXED;
2323             enc = fixed_enc;
2324         }
2325     }
2326     else if (!(options & ARG_ENCODING_FIXED)) {
2327        enc = rb_usascii_encoding();
2328     }
2329
2330     rb_enc_associate((VALUE)re, enc);
2331     if ((options & ARG_ENCODING_FIXED) || fixed_enc) {
2332         re->basic.flags |= KCODE_FIXED;
2333     }
2334     if (options & ARG_ENCODING_NONE) {
2335         re->basic.flags |= REG_ENCODING_NONE;
2336     }
2337
2338     re->ptr = make_regexp(RSTRING_PTR(unescaped), RSTRING_LEN(unescaped), enc,
2339                           options & ARG_REG_OPTION_MASK, err);
2340     if (!re->ptr) return -1;
2341     re->src = rb_enc_str_new(s, len, enc);
2342     OBJ_FREEZE(re->src);
2343     RB_GC_GUARD(unescaped);
2344     return 0;
2345 }
2346
2347 static int
2348 rb_reg_initialize_str(VALUE obj, VALUE str, int options, onig_errmsg_buffer err)
2349 {
2350     int ret;
2351     rb_encoding *enc = rb_enc_get(str);
2352     if (options & ARG_ENCODING_NONE) {
2353         rb_encoding *ascii8bit = rb_ascii8bit_encoding();
2354         if (enc != ascii8bit) {
2355             if (rb_enc_str_coderange(str) != ENC_CODERANGE_7BIT) {
2356                 strcpy(err, "/.../n has a non escaped non ASCII character in non ASCII-8BIT script");
2357                 return -1;
2358             }
2359             enc = ascii8bit;
2360         }
2361     }
2362     ret = rb_reg_initialize(obj, RSTRING_PTR(str), RSTRING_LEN(str), enc,
2363                             options, err);
2364     RB_GC_GUARD(str);
2365     return ret;
2366 }
2367
2368 static VALUE
2369 rb_reg_s_alloc(VALUE klass)
2370 {
2371     NEWOBJ(re, struct RRegexp);
2372     OBJSETUP(re, klass, T_REGEXP);
2373
2374     re->ptr = 0;
2375     re->src = 0;
2376     re->usecnt = 0;
2377
2378     return (VALUE)re;
2379 }
2380
2381 VALUE
2382 rb_reg_new_str(VALUE s, int options)
2383 {
2384     VALUE re = rb_reg_s_alloc(rb_cRegexp);
2385     onig_errmsg_buffer err = "";
2386
2387     if (rb_reg_initialize_str(re, s, options, err) != 0) {
2388         rb_reg_raise_str(s, options, err);
2389     }
2390
2391     return re;
2392 }
2393
2394 VALUE
2395 rb_reg_new_ary(VALUE ary, int opt)
2396 {
2397     return rb_reg_new_str(rb_reg_preprocess_dregexp(ary), opt);
2398 }
2399
2400 VALUE
2401 rb_enc_reg_new(const char *s, long len, rb_encoding *enc, int options)
2402 {
2403     VALUE re = rb_reg_s_alloc(rb_cRegexp);
2404     onig_errmsg_buffer err = "";
2405
2406     if (rb_reg_initialize(re, s, len, enc, options, err) != 0) {
2407         rb_enc_reg_raise(s, len, enc, options, err);
2408     }
2409
2410     return re;
2411 }
2412
2413 VALUE
2414 rb_reg_new(const char *s, long len, int options)
2415 {
2416     return rb_enc_reg_new(s, len, rb_ascii8bit_encoding(), options);
2417 }
2418
2419 VALUE
2420 rb_reg_compile(VALUE str, int options)
2421 {
2422     VALUE re = rb_reg_s_alloc(rb_cRegexp);
2423     onig_errmsg_buffer err = "";
2424
2425     if (!str) str = rb_str_new(0,0);
2426     if (rb_reg_initialize_str(re, str, options, err) != 0) {
2427         rb_set_errinfo(rb_reg_error_desc(str, options, err));
2428         return Qnil;
2429     }
2430     FL_SET(re, REG_LITERAL);
2431     return re;
2432 }
2433
2434 static VALUE reg_cache;
2435
2436 VALUE
2437 rb_reg_regcomp(VALUE str)
2438 {
2439     volatile VALUE save_str = str;
2440     if (reg_cache && RREGEXP_SRC_LEN(reg_cache) == RSTRING_LEN(str)
2441         && ENCODING_GET(reg_cache) == ENCODING_GET(str)
2442         && memcmp(RREGEXP_SRC_PTR(reg_cache), RSTRING_PTR(str), RSTRING_LEN(str)) == 0)
2443         return reg_cache;
2444
2445     return reg_cache = rb_reg_new_str(save_str, 0);
2446 }
2447
2448 /*
2449  * call-seq:
2450  *   rxp.hash   => fixnum
2451  *
2452  * Produce a hash based on the text and options of this regular expression.
2453  */
2454
2455 static VALUE
2456 rb_reg_hash(VALUE re)
2457 {
2458     int hashval, len;
2459     char *p;
2460
2461     rb_reg_check(re);
2462     hashval = RREGEXP(re)->ptr->options;
2463     len = RREGEXP_SRC_LEN(re);
2464     p  = RREGEXP_SRC_PTR(re);
2465     while (len--) {
2466         hashval = hashval * 33 + *p++;
2467     }
2468     hashval = hashval + (hashval>>5);
2469
2470     return INT2FIX(hashval);
2471 }
2472
2473
2474 /*
2475  *  call-seq:
2476  *     rxp == other_rxp      => true or false
2477  *     rxp.eql?(other_rxp)   => true or false
2478  *
2479  *  Equality---Two regexps are equal if their patterns are identical, they have
2480  *  the same character set code, and their <code>casefold?</code> values are the
2481  *  same.
2482  *
2483  *     /abc/  == /abc/x   #=> false
2484  *     /abc/  == /abc/i   #=> false
2485  *     /abc/  == /abc/n   #=> false
2486  *     /abc/u == /abc/n   #=> false
2487  */
2488
2489 static VALUE
2490 rb_reg_equal(VALUE re1, VALUE re2)
2491 {
2492     if (re1 == re2) return Qtrue;
2493     if (TYPE(re2) != T_REGEXP) return Qfalse;
2494     rb_reg_check(re1); rb_reg_check(re2);
2495     if (FL_TEST(re1, KCODE_FIXED) != FL_TEST(re2, KCODE_FIXED)) return Qfalse;
2496     if (RREGEXP(re1)->ptr->options != RREGEXP(re2)->ptr->options) return Qfalse;
2497     if (RREGEXP_SRC_LEN(re1) != RREGEXP_SRC_LEN(re2)) return Qfalse;
2498     if (ENCODING_GET(re1) != ENCODING_GET(re2)) return Qfalse;
2499     if (memcmp(RREGEXP_SRC_PTR(re1), RREGEXP_SRC_PTR(re2), RREGEXP_SRC_LEN(re1)) == 0) {
2500         return Qtrue;
2501     }
2502     return Qfalse;
2503 }
2504
2505 static VALUE
2506 reg_operand(VALUE s, int check)
2507 {
2508     if (SYMBOL_P(s)) {
2509         return rb_sym_to_s(s);
2510     }
2511     else {
2512         VALUE tmp = rb_check_string_type(s);
2513         if (check && NIL_P(tmp)) {
2514             rb_raise(rb_eTypeError, "can't convert %s to String",
2515                      rb_obj_classname(s));
2516         }
2517         return tmp;
2518     }
2519 }
2520
2521 static long
2522 reg_match_pos(VALUE re, VALUE *strp, long pos)
2523 {
2524     VALUE str = *strp;
2525
2526     if (NIL_P(str)) {
2527         rb_backref_set(Qnil);
2528         return -1;
2529     }
2530     *strp = str = reg_operand(str, Qtrue);
2531     if (pos != 0) {
2532         if (pos < 0) {
2533             VALUE l = rb_str_length(str);
2534             pos += NUM2INT(l);
2535             if (pos < 0) {
2536                 return pos;
2537             }
2538         }
2539         pos = rb_reg_adjust_startpos(re, str, pos, 0);
2540     }
2541     return rb_reg_search(re, str, pos, 0);
2542 }
2543
2544 /*
2545  *  call-seq:
2546  *     rxp =~ str    => integer or nil
2547  *
2548  *  Match---Matches <i>rxp</i> against <i>str</i>.
2549  *
2550  *     /at/ =~ "input data"   #=> 7
2551  *     /ax/ =~ "input data"   #=> nil
2552  *
2553  *  If <code>=~</code> is used with a regexp literal with named captures,
2554  *  captured strings (or nil) is assigned to local variables named by
2555  *  the capture names.
2556  *
2557  *     /(?<lhs>\w+)\s*=\s*(?<rhs>\w+)/ =~ "  x = y  "
2558  *     p lhs    #=> "x"
2559  *     p rhs    #=> "y"
2560  *
2561  *  If it is not matched, nil is assigned for the variables.
2562  *
2563  *     /(?<lhs>\w+)\s*=\s*(?<rhs>\w+)/ =~ "  x = "
2564  *     p lhs    #=> nil
2565  *     p rhs    #=> nil
2566  *
2567  *  This assignment is implemented in the Ruby parser.
2568  *  So a regexp literal is required for the assignment.
2569  *  The assignment is not occur if the regexp is not a literal.
2570  *
2571  *     re = /(?<lhs>\w+)\s*=\s*(?<rhs>\w+)/
2572  *     re =~ "  x = "
2573  *     p lhs    # undefined local variable
2574  *     p rhs    # undefined local variable
2575  *
2576  *  A regexp interpolation, <code>#{}</code>, also disables
2577  *  the assignment.
2578  *
2579  *     rhs_pat = /(?<rhs>\w+)/
2580  *     /(?<lhs>\w+)\s*=\s*#{rhs_pat}/ =~ "x = y"
2581  *     p lhs    # undefined local variable
2582  *
2583  */
2584
2585 VALUE
2586 rb_reg_match(VALUE re, VALUE str)
2587 {
2588     long pos = reg_match_pos(re, &str, 0);
2589     if (pos < 0) return Qnil;
2590     pos = rb_str_sublen(str, pos);
2591     return LONG2FIX(pos);
2592 }
2593
2594 /*
2595  *  call-seq:
2596  *     rxp === str   => true or false
2597  *
2598  *  Case Equality---Synonym for <code>Regexp#=~</code> used in case statements.
2599  *
2600  *     a = "HELLO"
2601  *     case a
2602  *     when /^[a-z]*$/; print "Lower case\n"
2603  *     when /^[A-Z]*$/; print "Upper case\n"
2604  *     else;            print "Mixed case\n"
2605  *     end
2606  *
2607  *  <em>produces:</em>
2608  *
2609  *     Upper case
2610  */
2611
2612 VALUE
2613 rb_reg_eqq(VALUE re, VALUE str)
2614 {
2615     long start;
2616
2617     str = reg_operand(str, Qfalse);
2618     if (NIL_P(str)) {
2619         rb_backref_set(Qnil);
2620         return Qfalse;
2621     }
2622     start = rb_reg_search(re, str, 0, 0);
2623     if (start < 0) {
2624         return Qfalse;
2625     }
2626     return Qtrue;
2627 }
2628
2629
2630 /*
2631  *  call-seq:
2632  *     ~ rxp   => integer or nil
2633  *
2634  *  Match---Matches <i>rxp</i> against the contents of <code>$_</code>.
2635  *  Equivalent to <code><i>rxp</i> =~ $_</code>.
2636  *
2637  *     $_ = "input data"
2638  *     ~ /at/   #=> 7
2639  */
2640
2641 VALUE
2642 rb_reg_match2(VALUE re)
2643 {
2644     long start;
2645     VALUE line = rb_lastline_get();
2646
2647     if (TYPE(line) != T_STRING) {
2648         rb_backref_set(Qnil);
2649         return Qnil;
2650     }
2651
2652     start = rb_reg_search(re, line, 0, 0);
2653     if (start < 0) {
2654         return Qnil;
2655     }
2656     start = rb_str_sublen(line, start);
2657     return LONG2FIX(start);
2658 }
2659
2660
2661 /*
2662  *  call-seq:
2663  *     rxp.match(str)       => matchdata or nil
2664  *     rxp.match(str,pos)   => matchdata or nil
2665  *
2666  *  Returns a <code>MatchData</code> object describing the match, or
2667  *  <code>nil</code> if there was no match. This is equivalent to retrieving the
2668  *  value of the special variable <code>$~</code> following a normal match.
2669  *  If the second parameter is present, it specifies the position in the string
2670  *  to begin the search.
2671  *
2672  *     /(.)(.)(.)/.match("abc")[2]   #=> "b"
2673  *     /(.)(.)/.match("abc", 1)[2]   #=> "c"
2674  *
2675  *  If a block is given, invoke the block with MatchData if match succeed, so
2676  *  that you can write
2677  *
2678  *     pat.match(str) {|m| ...}
2679  *
2680  *  instead of
2681  *
2682  *     if m = pat.match(str)
2683  *       ...
2684  *     end
2685  *
2686  *  The return value is a value from block execution in this case.
2687  */
2688
2689 static VALUE
2690 rb_reg_match_m(int argc, VALUE *argv, VALUE re)
2691 {
2692     VALUE result, str, initpos;
2693     long pos;
2694
2695     if (rb_scan_args(argc, argv, "11", &str, &initpos) == 2) {
2696         pos = NUM2LONG(initpos);
2697     }
2698     else {
2699         pos = 0;
2700     }
2701
2702     pos = reg_match_pos(re, &str, pos);
2703     if (pos < 0) {
2704         rb_backref_set(Qnil);
2705         return Qnil;
2706     }
2707     result = rb_backref_get();
2708     rb_match_busy(result);
2709     if (!NIL_P(result) && rb_block_given_p()) {
2710         return rb_yield(result);
2711     }
2712     return result;
2713 }
2714
2715 /*
2716  * Document-method: compile
2717  *
2718  * Synonym for <code>Regexp.new</code>
2719  */
2720
2721
2722 /*
2723  *  call-seq:
2724  *     Regexp.new(string [, options])                => regexp
2725  *     Regexp.new(regexp)                            => regexp
2726  *     Regexp.compile(string [, options])            => regexp
2727  *     Regexp.compile(regexp)                        => regexp
2728  *
2729  *  Constructs a new regular expression from <i>pattern</i>, which can be either
2730  *  a <code>String</code> or a <code>Regexp</code> (in which case that regexp's
2731  *  options are propagated, and new options may not be specified (a change as of
2732  *  Ruby 1.8). If <i>options</i> is a <code>Fixnum</code>, it should be one or
2733  *  more of the constants <code>Regexp::EXTENDED</code>,
2734  *  <code>Regexp::IGNORECASE</code>, and <code>Regexp::MULTILINE</code>,
2735  *  <em>or</em>-ed together. Otherwise, if <i>options</i> is not
2736  *  <code>nil</code>, the regexp will be case insensitive.
2737  *
2738  *     r1 = Regexp.new('^a-z+:\\s+\w+')           #=> /^a-z+:\s+\w+/
2739  *     r2 = Regexp.new('cat', true)               #=> /cat/i
2740  *     r3 = Regexp.new('dog', Regexp::EXTENDED)   #=> /dog/x
2741  *     r4 = Regexp.new(r2)                        #=> /cat/i
2742  */
2743
2744 static VALUE
2745 rb_reg_initialize_m(int argc, VALUE *argv, VALUE self)
2746 {
2747     onig_errmsg_buffer err = "";
2748     int flags = 0;
2749     VALUE str;
2750     rb_encoding *enc;
2751     const char *ptr;
2752     long len;
2753
2754     if (argc == 0 || argc > 3) {
2755         rb_raise(rb_eArgError, "wrong number of arguments");
2756     }
2757     if (TYPE(argv[0]) == T_REGEXP) {
2758         VALUE re = argv[0];
2759
2760         if (argc > 1) {
2761             rb_warn("flags ignored");
2762         }
2763         rb_reg_check(re);
2764         flags = rb_reg_options(re);
2765         ptr = RREGEXP_SRC_PTR(re);
2766         len = RREGEXP_SRC_LEN(re);
2767         enc = rb_enc_get(re);
2768         if (rb_reg_initialize(self, ptr, len, enc, flags, err)) {
2769             str = rb_enc_str_new(ptr, len, enc);
2770             rb_reg_raise_str(str, flags, err);
2771         }
2772     }
2773     else {
2774         if (argc >= 2) {
2775             if (FIXNUM_P(argv[1])) flags = FIX2INT(argv[1]);
2776             else if (RTEST(argv[1])) flags = ONIG_OPTION_IGNORECASE;
2777         }
2778         enc = 0;
2779         if (argc == 3 && !NIL_P(argv[2])) {
2780             char *kcode = StringValuePtr(argv[2]);
2781             if (kcode[0] == 'n' || kcode[1] == 'N') {
2782                 enc = rb_ascii8bit_encoding();
2783                 flags |= ARG_ENCODING_FIXED;
2784             }
2785             else {
2786                 rb_warning("encoding option is obsolete - %s", kcode);
2787             }
2788         }
2789         str = argv[0];
2790         ptr = StringValuePtr(str);
2791         if (enc
2792             ? rb_reg_initialize(self, ptr, RSTRING_LEN(str), enc, flags, err)
2793             : rb_reg_initialize_str(self, str, flags, err)) {
2794             rb_reg_raise_str(str, flags, err);
2795         }
2796     }
2797     return self;
2798 }
2799
2800 VALUE
2801 rb_reg_quote(VALUE str)
2802 {
2803     rb_encoding *enc = rb_enc_get(str);
2804     char *s, *send, *t;
2805     VALUE tmp;
2806     int c, clen;
2807     int ascii_only = rb_enc_str_asciionly_p(str);
2808
2809     s = RSTRING_PTR(str);
2810     send = s + RSTRING_LEN(str);
2811     while (s < send) {
2812         c = rb_enc_ascget(s, send, &clen, enc);
2813         if (c == -1) {
2814             s += mbclen(s, send, enc);
2815             continue;
2816         }
2817         switch (c) {
2818           case '[': case ']': case '{': case '}':
2819           case '(': case ')': case '|': case '-':
2820           case '*': case '.': case '\\':
2821           case '?': case '+': case '^': case '$':
2822           case ' ': case '#':
2823           case '\t': case '\f': case '\v': case '\n': case '\r':
2824             goto meta_found;
2825         }
2826         s += clen;
2827     }
2828     tmp = rb_str_new3(str);
2829     if (ascii_only) {
2830         rb_enc_associate(tmp, rb_usascii_encoding());
2831     }
2832     return tmp;
2833
2834   meta_found:
2835     tmp = rb_str_new(0, RSTRING_LEN(str)*2);
2836     if (ascii_only) {
2837         rb_enc_associate(tmp, rb_usascii_encoding());
2838     }
2839     else {
2840         rb_enc_copy(tmp, str);
2841     }
2842     t = RSTRING_PTR(tmp);
2843     /* copy upto metacharacter */
2844     memcpy(t, RSTRING_PTR(str), s - RSTRING_PTR(str));
2845     t += s - RSTRING_PTR(str);
2846
2847     while (s < send) {
2848         c = rb_enc_ascget(s, send, &clen, enc);
2849         if (c == -1) {
2850             int n = mbclen(s, send, enc);
2851
2852             while (n--)
2853                 *t++ = *s++;
2854             continue;
2855         }
2856         s += clen;
2857         switch (c) {
2858           case '[': case ']': case '{': case '}':
2859           case '(': case ')': case '|': case '-':
2860           case '*': case '.': case '\\':
2861           case '?': case '+': case '^': case '$':
2862           case '#':
2863             *t++ = '\\';
2864             break;
2865           case ' ':
2866             *t++ = '\\';
2867             *t++ = ' ';
2868             continue;
2869           case '\t':
2870             *t++ = '\\';
2871             *t++ = 't';
2872             continue;
2873           case '\n':
2874             *t++ = '\\';
2875             *t++ = 'n';
2876             continue;
2877           case '\r':
2878             *t++ = '\\';
2879             *t++ = 'r';
2880             continue;
2881           case '\f':
2882             *t++ = '\\';
2883             *t++ = 'f';
2884             continue;
2885           case '\v':
2886             *t++ = '\\';
2887             *t++ = 'v';
2888             continue;
2889         }
2890         *t++ = c;
2891     }
2892     rb_str_resize(tmp, t - RSTRING_PTR(tmp));
2893     OBJ_INFECT(tmp, str);
2894     return tmp;
2895 }
2896
2897
2898 /*
2899  *  call-seq:
2900  *     Regexp.escape(str)   => string
2901  *     Regexp.quote(str)    => string
2902  *
2903  *  Escapes any characters that would have special meaning in a regular
2904  *  expression. Returns a new escaped string, or self if no characters are
2905  *  escaped.  For any string,
2906  *  <code>Regexp.new(Regexp.escape(<i>str</i>))=~<i>str</i></code> will be true.
2907  *
2908  *     Regexp.escape('\*?{}.')   #=> \\\*\?\{\}\.
2909  *
2910  */
2911
2912 static VALUE
2913 rb_reg_s_quote(VALUE c, VALUE str)
2914 {
2915     return rb_reg_quote(reg_operand(str, Qtrue));
2916 }
2917
2918 int
2919 rb_reg_options(VALUE re)
2920 {
2921     int options;
2922
2923     rb_reg_check(re);
2924     options = RREGEXP(re)->ptr->options & ARG_REG_OPTION_MASK;
2925     if (RBASIC(re)->flags & KCODE_FIXED) options |= ARG_ENCODING_FIXED;
2926     if (RBASIC(re)->flags & REG_ENCODING_NONE) options |= ARG_ENCODING_NONE;
2927     return options;
2928 }
2929
2930 VALUE
2931 rb_check_regexp_type(VALUE re)
2932 {
2933     return rb_check_convert_type(re, T_REGEXP, "Regexp", "to_regexp");
2934 }
2935
2936 /*
2937  *  call-seq:
2938  *     Regexp.try_convert(obj) -> re or nil
2939  *
2940  *  Try to convert <i>obj</i> into a Regexp, using to_regexp method.
2941  *  Returns converted regexp or nil if <i>obj</i> cannot be converted
2942  *  for any reason.
2943  *
2944  *     Regexp.try_convert(/re/)         #=> /re/
2945  *     Regexp.try_convert("re")         #=> nil
2946  *
2947  *     o = Object.new
2948  *     Regexp.try_convert(o)            #=> nil
2949  *     def o.to_regexp() /foo/ end
2950  *     Regexp.try_convert(o)            #=> /foo/
2951  *
2952  */
2953 static VALUE
2954 rb_reg_s_try_convert(VALUE dummy, VALUE re)
2955 {
2956     return rb_check_regexp_type(re);
2957 }
2958
2959 static VALUE
2960 rb_reg_s_union(VALUE self, VALUE args0)
2961 {
2962     long argc = RARRAY_LEN(args0);
2963
2964     if (argc == 0) {
2965         VALUE args[1];
2966         args[0] = rb_str_new2("(?!)");
2967         return rb_class_new_instance(1, args, rb_cRegexp);
2968     }
2969     else if (argc == 1) {
2970         VALUE arg = rb_ary_entry(args0, 0);
2971         VALUE re = rb_check_regexp_type(arg);
2972         if (!NIL_P(re))
2973             return re;
2974         else {
2975             VALUE quoted;
2976             quoted = rb_reg_s_quote(Qnil, arg);
2977             return rb_reg_new_str(quoted, 0);
2978         }
2979     }
2980     else {
2981         int i;
2982         VALUE source = rb_str_buf_new(0);
2983         rb_encoding *result_enc;
2984
2985         int has_asciionly = 0;
2986         rb_encoding *has_ascii_compat_fixed = 0;
2987         rb_encoding *has_ascii_incompat = 0;
2988
2989         for (i = 0; i < argc; i++) {
2990             volatile VALUE v;
2991             VALUE e = rb_ary_entry(args0, i);
2992
2993             if (0 < i)
2994                 rb_str_buf_cat_ascii(source, "|");
2995
2996             v = rb_check_regexp_type(e);
2997             if (!NIL_P(v)) {
2998                 rb_encoding *enc = rb_enc_get(v);
2999                 if (!rb_enc_asciicompat(enc)) {
3000                     if (!has_ascii_incompat)
3001                         has_ascii_incompat = enc;
3002                     else if (has_ascii_incompat != enc)
3003                         rb_raise(rb_eArgError, "incompatible encodings: %s and %s",
3004                             rb_enc_name(has_ascii_incompat), rb_enc_name(enc));
3005                 }
3006                 else if (rb_reg_fixed_encoding_p(v)) {
3007                     if (!has_ascii_compat_fixed)
3008                         has_ascii_compat_fixed = enc;
3009                     else if (has_ascii_compat_fixed != enc)
3010                         rb_raise(rb_eArgError, "incompatible encodings: %s and %s",
3011                             rb_enc_name(has_ascii_compat_fixed), rb_enc_name(enc));
3012                 }
3013                 else {
3014                     has_asciionly = 1;
3015                 }
3016                 v = rb_reg_to_s(v);
3017             }
3018             else {
3019                 rb_encoding *enc;
3020                 StringValue(e);
3021                 enc = rb_enc_get(e);
3022                 if (!rb_enc_str_asciicompat_p(e)) {
3023                     if (!has_ascii_incompat)
3024                         has_ascii_incompat = enc;
3025                     else if (has_ascii_incompat != enc)
3026                         rb_raise(rb_eArgError, "incompatible encodings: %s and %s",
3027                             rb_enc_name(has_ascii_incompat), rb_enc_name(enc));
3028                 }
3029                 else if (rb_enc_str_asciionly_p(e)) {
3030                     has_asciionly = 1;
3031                 }
3032                 else {
3033                     if (!has_ascii_compat_fixed)
3034                         has_ascii_compat_fixed = enc;
3035                     else if (has_ascii_compat_fixed != enc)
3036                         rb_raise(rb_eArgError, "incompatible encodings: %s and %s",
3037                             rb_enc_name(has_ascii_compat_fixed), rb_enc_name(enc));
3038                 }
3039                 v = rb_reg_s_quote(Qnil, e);
3040             }
3041             if (has_ascii_incompat) {
3042                 if (has_asciionly) {
3043                     rb_raise(rb_eArgError, "ASCII incompatible encoding: %s",
3044                         rb_enc_name(has_ascii_incompat));
3045                 }
3046                 if (has_ascii_compat_fixed) {
3047                     rb_raise(rb_eArgError, "incompatible encodings: %s and %s",
3048                         rb_enc_name(has_ascii_incompat), rb_enc_name(has_ascii_compat_fixed));
3049                 }
3050             }
3051
3052             if (i == 0) {
3053                 rb_enc_copy(source, v);
3054             }
3055             rb_str_append(source, v);
3056         }
3057
3058         if (has_ascii_incompat) {
3059             result_enc = has_ascii_incompat;
3060         }
3061         else if (has_ascii_compat_fixed) {
3062             result_enc = has_ascii_compat_fixed;
3063         }
3064         else {
3065             result_enc = rb_ascii8bit_encoding();
3066         }
3067
3068         rb_enc_associate(source, result_enc);
3069         return rb_class_new_instance(1, &source, rb_cRegexp);
3070     }
3071 }
3072
3073 /*
3074  *  call-seq:
3075  *     Regexp.union(pat1, pat2, ...)            => new_regexp
3076  *     Regexp.union(pats_ary)                   => new_regexp
3077  *
3078  *  Return a <code>Regexp</code> object that is the union of the given
3079  *  <em>pattern</em>s, i.e., will match any of its parts. The <em>pattern</em>s
3080  *  can be Regexp objects, in which case their options will be preserved, or
3081  *  Strings. If no patterns are given, returns <code>/(?!)/</code>.
3082  *
3083  *     Regexp.union                         #=> /(?!)/
3084  *     Regexp.union("penzance")             #=> /penzance/
3085  *     Regexp.union("a+b*c")                #=> /a\+b\*c/
3086  *     Regexp.union("skiing", "sledding")   #=> /skiing|sledding/
3087  *     Regexp.union(["skiing", "sledding"]) #=> /skiing|sledding/
3088  *     Regexp.union(/dogs/, /cats/i)        #=> /(?-mix:dogs)|(?i-mx:cats)/
3089  */
3090 static VALUE
3091 rb_reg_s_union_m(VALUE self, VALUE args)
3092 {
3093     VALUE v;
3094     if (RARRAY_LEN(args) == 1 &&
3095         !NIL_P(v = rb_check_array_type(rb_ary_entry(args, 0)))) {
3096         return rb_reg_s_union(self, v);
3097     }
3098     return rb_reg_s_union(self, args);
3099 }
3100
3101 /* :nodoc: */
3102 static VALUE
3103 rb_reg_init_copy(VALUE copy, VALUE re)
3104 {
3105     onig_errmsg_buffer err = "";
3106     const char *s;
3107     long len;
3108
3109     if (copy == re) return copy;
3110     rb_check_frozen(copy);
3111     /* need better argument type check */
3112     if (!rb_obj_is_instance_of(re, rb_obj_class(copy))) {
3113         rb_raise(rb_eTypeError, "wrong argument type");
3114     }
3115     rb_reg_check(re);
3116     s = RREGEXP_SRC_PTR(re);
3117     len = RREGEXP_SRC_LEN(re);
3118     if (rb_reg_initialize(copy, s, len, rb_enc_get(re), rb_reg_options(re), err) != 0) {
3119         rb_reg_raise(s, len, err, re);
3120     }
3121     return copy;
3122 }
3123
3124 VALUE
3125 rb_reg_regsub(VALUE str, VALUE src, struct re_registers *regs, VALUE regexp)
3126 {
3127     VALUE val = 0;
3128     char *p, *s, *e;
3129     int no, clen;
3130     rb_encoding *str_enc = rb_enc_get(str);
3131     rb_encoding *src_enc = rb_enc_get(src);
3132     int acompat = rb_enc_asciicompat(str_enc);
3133 #define ASCGET(s,e,cl) (acompat ? (*cl=1,s[0]) : rb_enc_ascget(s, e, cl, str_enc))
3134
3135     p = s = RSTRING_PTR(str);
3136     e = s + RSTRING_LEN(str);
3137
3138     while (s < e) {
3139         int c = ASCGET(s, e, &clen);
3140         char *ss;
3141
3142         if (c == -1) {
3143             s += mbclen(s, e, str_enc);
3144             continue;
3145         }
3146         ss = s;
3147         s += clen;
3148
3149         if (c != '\\' || s == e) continue;
3150
3151         if (!val) {
3152             val = rb_str_buf_new(ss-p);
3153         }
3154         rb_enc_str_buf_cat(val, p, ss-p, str_enc);
3155
3156         c = ASCGET(s, e, &clen);
3157         if (c == -1) {
3158             s += mbclen(s, e, str_enc);
3159             rb_enc_str_buf_cat(val, ss, s-ss, str_enc);
3160             p = s;
3161             continue;
3162         }
3163         s += clen;
3164
3165         p = s;
3166         switch (c) {
3167           case '1': case '2': case '3': case '4':
3168           case '5': case '6': case '7': case '8': case '9':
3169             if (onig_noname_group_capture_is_active(RREGEXP(regexp)->ptr)) {
3170                 no = c - '0';
3171             }
3172             else {
3173                 continue;
3174             }
3175             break;
3176
3177           case 'k':
3178             if (s < e && ASCGET(s, e, &clen) == '<') {
3179                 char *name, *name_end;
3180
3181                 name_end = name = s + clen;
3182                 while (name_end < e) {
3183                     c = ASCGET(name_end, e, &clen);
3184                     if (c == '>') break;
3185                     name_end += c == -1 ? mbclen(name_end, e, str_enc) : clen;
3186                 }
3187                 if (name_end < e) {
3188                     no = name_to_backref_number(regs, regexp, name, name_end);
3189                     p = s = name_end + clen;
3190                     break;
3191                 }
3192                 else {
3193                     rb_raise(rb_eRuntimeError, "invalid group name reference format");
3194                 }
3195             }
3196
3197             rb_enc_str_buf_cat(val, ss, s-ss, str_enc);
3198             continue;
3199
3200           case '0':
3201           case '&':
3202             no = 0;
3203             break;
3204
3205           case '`':
3206             rb_enc_str_buf_cat(val, RSTRING_PTR(src), BEG(0), src_enc);
3207             continue;
3208
3209           case '\'':
3210             rb_enc_str_buf_cat(val, RSTRING_PTR(src)+END(0), RSTRING_LEN(src)-END(0), src_enc);
3211             continue;
3212
3213           case '+':
3214             no = regs->num_regs-1;
3215             while (BEG(no) == -1 && no > 0) no--;
3216             if (no == 0) continue;
3217             break;
3218
3219           case '\\':
3220             rb_enc_str_buf_cat(val, s-clen, clen, str_enc);
3221             continue;
3222
3223           default:
3224             rb_enc_str_buf_cat(val, ss, s-ss, str_enc);
3225             continue;
3226         }
3227
3228         if (no >= 0) {
3229             if (no >= regs->num_regs) continue;
3230             if (BEG(no) == -1) continue;
3231             rb_enc_str_buf_cat(val, RSTRING_PTR(src)+BEG(no), END(no)-BEG(no), src_enc);
3232         }
3233     }
3234
3235     if (!val) return str;
3236     if (p < e) {
3237         rb_enc_str_buf_cat(val, p, e-p, str_enc);
3238     }
3239
3240     return val;
3241 }
3242
3243 static VALUE
3244 kcode_getter(void)
3245 {
3246     rb_warn("variable $KCODE is no longer effective");
3247     return Qnil;
3248 }
3249
3250 static void
3251 kcode_setter(VALUE val, ID id)
3252 {
3253     rb_warn("variable $KCODE is no longer effective; ignored");
3254 }
3255
3256 static VALUE
3257 ignorecase_getter(void)
3258 {
3259     rb_warn("variable $= is no longer effective");
3260     return Qfalse;
3261 }
3262
3263 static void
3264 ignorecase_setter(VALUE val, ID id)
3265 {
3266     rb_warn("variable $= is no longer effective; ignored");
3267 }
3268
3269 static VALUE
3270 match_getter(void)
3271 {
3272     VALUE match = rb_backref_get();
3273
3274     if (NIL_P(match)) return Qnil;
3275     rb_match_busy(match);
3276     return match;
3277 }
3278
3279 static void
3280 match_setter(VALUE val)
3281 {
3282     if (!NIL_P(val)) {
3283         Check_Type(val, T_MATCH);
3284     }
3285     rb_backref_set(val);
3286 }
3287
3288 /*
3289  *  call-seq:
3290  *     Regexp.last_match           => matchdata
3291  *     Regexp.last_match(n)        => str
3292  *
3293  *  The first form returns the <code>MatchData</code> object generated by the
3294  *  last successful pattern match. Equivalent to reading the global variable
3295  *  <code>$~</code>. The second form returns the <i>n</i>th field in this
3296  *  <code>MatchData</code> object.
3297  *  <em>n</em> can be a string or symbol to reference a named capture.
3298  *
3299  *     /c(.)t/ =~ 'cat'        #=> 0
3300  *     Regexp.last_match       #=> #<MatchData "cat" 1:"a">
3301  *     Regexp.last_match(0)    #=> "cat"
3302  *     Regexp.last_match(1)    #=> "a"
3303  *     Regexp.last_match(2)    #=> nil
3304  *
3305  *     /(?<lhs>\w+)\s*=\s*(?<rhs>\w+)/ =~ "var = val"
3306  *     Regexp.last_match       #=> #<MatchData "var = val" lhs:"var" rhs:"val">
3307  *     Regexp.last_match(:lhs) #=> "var"
3308  *     Regexp.last_match(:rhs) #=> "val"
3309  */
3310
3311 static VALUE
3312 rb_reg_s_last_match(int argc, VALUE *argv)
3313 {
3314     VALUE nth;
3315
3316     if (argc > 0 && rb_scan_args(argc, argv, "01", &nth) == 1) {
3317         VALUE match = rb_backref_get();
3318         int n;
3319         if (NIL_P(match)) return Qnil;
3320         n = match_backref_number(match, nth);
3321         return rb_reg_nth_match(n, match);
3322     }
3323     return match_getter();
3324 }
3325
3326 static void
3327 re_warn(const char *s)
3328 {
3329     rb_warn("%s", s);
3330 }
3331
3332 /*
3333  *  Document-class: Regexp
3334  *
3335  *  A <code>Regexp</code> holds a regular expression, used to match a pattern
3336  *  against strings. Regexps are created using the <code>/.../</code> and
3337  *  <code>%r{...}</code> literals, and by the <code>Regexp::new</code>
3338  *  constructor.
3339  *
3340  */
3341
3342 void
3343 Init_Regexp(void)
3344 {
3345     rb_eRegexpError = rb_define_class("RegexpError", rb_eStandardError);
3346
3347     onigenc_set_default_caseconv_table((UChar*)casetable);
3348     onigenc_set_default_encoding(ONIG_ENCODING_ASCII);
3349     onig_set_warn_func(re_warn);
3350     onig_set_verb_warn_func(re_warn);
3351
3352     rb_define_virtual_variable("$~", match_getter, match_setter);
3353     rb_define_virtual_variable("$&", last_match_getter, 0);
3354     rb_define_virtual_variable("$`", prematch_getter, 0);
3355     rb_define_virtual_variable("$'", postmatch_getter, 0);
3356     rb_define_virtual_variable("$+", last_paren_match_getter, 0);
3357
3358     rb_define_virtual_variable("$=", ignorecase_getter, ignorecase_setter);
3359     rb_define_virtual_variable("$KCODE", kcode_getter, kcode_setter);
3360     rb_define_virtual_variable("$-K", kcode_getter, kcode_setter);
3361
3362     rb_cRegexp = rb_define_class("Regexp", rb_cObject);
3363     rb_define_alloc_func(rb_cRegexp, rb_reg_s_alloc);
3364     rb_define_singleton_method(rb_cRegexp, "compile", rb_class_new_instance, -1);
3365     rb_define_singleton_method(rb_cRegexp, "quote", rb_reg_s_quote, 1);
3366     rb_define_singleton_method(rb_cRegexp, "escape", rb_reg_s_quote, 1);
3367     rb_define_singleton_method(rb_cRegexp, "union", rb_reg_s_union_m, -2);
3368     rb_define_singleton_method(rb_cRegexp, "last_match", rb_reg_s_last_match, -1);
3369     rb_define_singleton_method(rb_cRegexp, "try_convert", rb_reg_s_try_convert, 1);
3370
3371     rb_define_method(rb_cRegexp, "initialize", rb_reg_initialize_m, -1);
3372     rb_define_method(rb_cRegexp, "initialize_copy", rb_reg_init_copy, 1);
3373     rb_define_method(rb_cRegexp, "hash", rb_reg_hash, 0);
3374     rb_define_method(rb_cRegexp, "eql?", rb_reg_equal, 1);
3375     rb_define_method(rb_cRegexp, "==", rb_reg_equal, 1);
3376     rb_define_method(rb_cRegexp, "=~", rb_reg_match, 1);
3377     rb_define_method(rb_cRegexp, "===", rb_reg_eqq, 1);
3378     rb_define_method(rb_cRegexp, "~", rb_reg_match2, 0);
3379     rb_define_method(rb_cRegexp, "match", rb_reg_match_m, -1);
3380     rb_define_method(rb_cRegexp, "to_s", rb_reg_to_s, 0);
3381     rb_define_method(rb_cRegexp, "inspect", rb_reg_inspect, 0);
3382     rb_define_method(rb_cRegexp, "source", rb_reg_source, 0);
3383     rb_define_method(rb_cRegexp, "casefold?", rb_reg_casefold_p, 0);
3384     rb_define_method(rb_cRegexp, "options", rb_reg_options_m, 0);
3385     rb_define_method(rb_cRegexp, "encoding", rb_obj_encoding, 0); /* in encoding.c */
3386     rb_define_method(rb_cRegexp, "fixed_encoding?", rb_reg_fixed_encoding_p, 0);
3387     rb_define_method(rb_cRegexp, "names", rb_reg_names, 0);
3388     rb_define_method(rb_cRegexp, "named_captures", rb_reg_named_captures, 0);
3389
3390     rb_define_const(rb_cRegexp, "IGNORECASE", INT2FIX(ONIG_OPTION_IGNORECASE));
3391     rb_define_const(rb_cRegexp, "EXTENDED", INT2FIX(ONIG_OPTION_EXTEND));
3392     rb_define_const(rb_cRegexp, "MULTILINE", INT2FIX(ONIG_OPTION_MULTILINE));
3393
3394     rb_global_variable(&reg_cache);
3395
3396     rb_cMatch  = rb_define_class("MatchData", rb_cObject);
3397     rb_define_alloc_func(rb_cMatch, match_alloc);
3398     rb_undef_method(CLASS_OF(rb_cMatch), "new");
3399
3400     rb_define_method(rb_cMatch, "initialize_copy", match_init_copy, 1);
3401     rb_define_method(rb_cMatch, "regexp", match_regexp, 0);
3402     rb_define_method(rb_cMatch, "names", match_names, 0);
3403     rb_define_method(rb_cMatch, "size", match_size, 0);
3404     rb_define_method(rb_cMatch, "length", match_size, 0);
3405     rb_define_method(rb_cMatch, "offset", match_offset, 1);
3406     rb_define_method(rb_cMatch, "begin", match_begin, 1);
3407     rb_define_method(rb_cMatch, "end", match_end, 1);
3408     rb_define_method(rb_cMatch, "to_a", match_to_a, 0);
3409     rb_define_method(rb_cMatch, "[]", match_aref, -1);
3410     rb_define_method(rb_cMatch, "captures", match_captures, 0);
3411     rb_define_method(rb_cMatch, "values_at", match_values_at, -1);
3412     rb_define_method(rb_cMatch, "pre_match", rb_reg_match_pre, 0);
3413     rb_define_method(rb_cMatch, "post_match", rb_reg_match_post, 0);
3414     rb_define_method(rb_cMatch, "to_s", match_to_s, 0);
3415     rb_define_method(rb_cMatch, "inspect", match_inspect, 0);
3416     rb_define_method(rb_cMatch, "string", match_string, 0);
3417 }