range.c

   1 /**********************************************************************
   2
   3   range.c -
   4
   5   $Author$
   6   created at: Thu Aug 19 17:46:47 JST 1993
   7
   8   Copyright (C) 1993-2007 Yukihiro Matsumoto
   9
  10 **********************************************************************/
  11
  12 #include "ruby/ruby.h"
  13 #include "ruby/encoding.h"
  14
  15 VALUE rb_cRange;
  16 static ID id_cmp, id_succ, id_beg, id_end, id_excl;
  17
  18 #define RANGE_BEG(r) (RSTRUCT(r)->as.ary[0])
  19 #define RANGE_END(r) (RSTRUCT(r)->as.ary[1])
  20 #define RANGE_EXCL(r) (RSTRUCT(r)->as.ary[2])
  21
  22 #define EXCL(r) RTEST(RANGE_EXCL(r))
  23 #define SET_EXCL(r,v) (RSTRUCT(r)->as.ary[2] = (v) ? Qtrue : Qfalse)
  24
  25 static VALUE
  26 range_failed(void)
  27 {
  28     rb_raise(rb_eArgError, "bad value for range");
  29     return Qnil;                /* dummy */
  30 }
  31
  32 static VALUE
  33 range_check(VALUE *args)
  34 {
  35     return rb_funcall(args[0], id_cmp, 1, args[1]);
  36 }
  37
  38 static void
  39 range_init(VALUE range, VALUE beg, VALUE end, int exclude_end)
  40 {
  41     VALUE args[2];
  42
  43     args[0] = beg;
  44     args[1] = end;
  45
  46     if (!FIXNUM_P(beg) || !FIXNUM_P(end)) {
  47         VALUE v;
  48
  49         v = rb_rescue(range_check, (VALUE)args, range_failed, 0);
  50         if (NIL_P(v))
  51             range_failed();
  52     }
  53
  54     SET_EXCL(range, exclude_end);
  55     RSTRUCT(range)->as.ary[0] = beg;
  56     RSTRUCT(range)->as.ary[1] = end;
  57 }
  58
  59 VALUE
  60 rb_range_new(VALUE beg, VALUE end, int exclude_end)
  61 {
  62     VALUE range = rb_obj_alloc(rb_cRange);
  63
  64     range_init(range, beg, end, exclude_end);
  65     return range;
  66 }
  67
  68 /*
  69  *  call-seq:
  70  *     Range.new(start, end, exclusive=false)    => range
  71  *
  72  *  Constructs a range using the given <i>start</i> and <i>end</i>. If the third
  73  *  parameter is omitted or is <code>false</code>, the <i>range</i> will include
  74  *  the end object; otherwise, it will be excluded.
  75  */
  76
  77 static VALUE
  78 range_initialize(int argc, VALUE *argv, VALUE range)
  79 {
  80     VALUE beg, end, flags;
  81
  82     rb_scan_args(argc, argv, "21", &beg, &end, &flags);
  83     /* Ranges are immutable, so that they should be initialized only once. */
  84     if (RANGE_EXCL(range) != Qnil) {
  85         rb_name_error(rb_intern("initialize"), "`initialize' called twice");
  86     }
  87     range_init(range, beg, end, RTEST(flags));
  88     return Qnil;
  89 }
  90
  91
  92 /*
  93  *  call-seq:
  94  *     rng.exclude_end?    => true or false
  95  *
  96  *  Returns <code>true</code> if <i>rng</i> excludes its end value.
  97  */
  98
  99 static VALUE
 100 range_exclude_end_p(VALUE range)
 101 {
 102     return EXCL(range) ? Qtrue : Qfalse;
 103 }
 104
 105
 106 /*
 107  *  call-seq:
 108  *     rng == obj    => true or false
 109  *
 110  *  Returns <code>true</code> only if <i>obj</i> is a Range, has equivalent
 111  *  beginning and end items (by comparing them with <code>==</code>), and has
 112  *  the same #exclude_end? setting as <i>rng</t>.
 113  *
 114  *    (0..2) == (0..2)            #=> true
 115  *    (0..2) == Range.new(0,2)    #=> true
 116  *    (0..2) == (0...2)           #=> false
 117  *
 118  */
 119
 120 static VALUE
 121 range_eq(VALUE range, VALUE obj)
 122 {
 123     if (range == obj)
 124         return Qtrue;
 125     if (!rb_obj_is_instance_of(obj, rb_obj_class(range)))
 126         return Qfalse;
 127
 128     if (!rb_equal(RANGE_BEG(range), RANGE_BEG(obj)))
 129         return Qfalse;
 130     if (!rb_equal(RANGE_END(range), RANGE_END(obj)))
 131         return Qfalse;
 132
 133     if (EXCL(range) != EXCL(obj))
 134         return Qfalse;
 135
 136     return Qtrue;
 137 }
 138
 139 static int
 140 r_lt(VALUE a, VALUE b)
 141 {
 142     VALUE r = rb_funcall(a, id_cmp, 1, b);
 143
 144     if (NIL_P(r))
 145         return Qfalse;
 146     if (rb_cmpint(r, a, b) < 0)
 147         return Qtrue;
 148     return Qfalse;
 149 }
 150
 151 static int
 152 r_le(VALUE a, VALUE b)
 153 {
 154     int c;
 155     VALUE r = rb_funcall(a, id_cmp, 1, b);
 156
 157     if (NIL_P(r))
 158         return Qfalse;
 159     c = rb_cmpint(r, a, b);
 160     if (c == 0)
 161         return INT2FIX(0);
 162     if (c < 0)
 163         return Qtrue;
 164     return Qfalse;
 165 }
 166
 167
 168 /*
 169  *  call-seq:
 170  *     rng.eql?(obj)    => true or false
 171  *
 172  *  Returns <code>true</code> only if <i>obj</i> is a Range, has equivalent
 173  *  beginning and end items (by comparing them with #eql?), and has the same
 174  *  #exclude_end? setting as <i>rng</i>.
 175  *
 176  *    (0..2) == (0..2)            #=> true
 177  *    (0..2) == Range.new(0,2)    #=> true
 178  *    (0..2) == (0...2)           #=> false
 179  *
 180  */
 181
 182 static VALUE
 183 range_eql(VALUE range, VALUE obj)
 184 {
 185     if (range == obj)
 186         return Qtrue;
 187     if (!rb_obj_is_instance_of(obj, rb_obj_class(range)))
 188         return Qfalse;
 189
 190     if (!rb_eql(RANGE_BEG(range), RANGE_BEG(obj)))
 191         return Qfalse;
 192     if (!rb_eql(RANGE_END(range), RANGE_END(obj)))
 193         return Qfalse;
 194
 195     if (EXCL(range) != EXCL(obj))
 196         return Qfalse;
 197
 198     return Qtrue;
 199 }
 200
 201 /*
 202  * call-seq:
 203  *   rng.hash    => fixnum
 204  *
 205  * Generate a hash value such that two ranges with the same start and
 206  * end points, and the same value for the "exclude end" flag, generate
 207  * the same hash value.
 208  */
 209
 210 static VALUE
 211 range_hash(VALUE range)
 212 {
 213     long hash = EXCL(range);
 214     VALUE v;
 215
 216     v = rb_hash(RANGE_BEG(range));
 217     hash ^= v << 1;
 218     v = rb_hash(RANGE_END(range));
 219     hash ^= v << 9;
 220     hash ^= EXCL(range) << 24;
 221
 222     return LONG2FIX(hash);
 223 }
 224
 225 static void
 226 range_each_func(VALUE range, VALUE (*func) (VALUE, void *), void *arg)
 227 {
 228     int c;
 229     VALUE b = RANGE_BEG(range);
 230     VALUE e = RANGE_END(range);
 231     VALUE v = b;
 232
 233     if (EXCL(range)) {
 234         while (r_lt(v, e)) {
 235             (*func) (v, arg);
 236             v = rb_funcall(v, id_succ, 0, 0);
 237         }
 238     }
 239     else {
 240         while (RTEST(c = r_le(v, e))) {
 241             (*func) (v, arg);
 242             if (c == INT2FIX(0))
 243                 break;
 244             v = rb_funcall(v, id_succ, 0, 0);
 245         }
 246     }
 247 }
 248
 249 static VALUE
 250 step_i(VALUE i, void *arg)
 251 {
 252     VALUE *iter = arg;
 253
 254     if (FIXNUM_P(iter[0])) {
 255         iter[0] -= INT2FIX(1) & ~FIXNUM_FLAG;
 256     }
 257     else {
 258         iter[0] = rb_funcall(iter[0], '-', 1, INT2FIX(1));
 259     }
 260     if (iter[0] == INT2FIX(0)) {
 261         rb_yield(i);
 262         iter[0] = iter[1];
 263     }
 264     return Qnil;
 265 }
 266
 267 /*
 268  *  call-seq:
 269  *     rng.step(n=1) {| obj | block }    => rng
 270  *
 271  *  Iterates over <i>rng</i>, passing each <i>n</i>th element to the block. If
 272  *  the range contains numbers, <i>n</i> is added for each iteration.  Otherwise
 273  *  <code>step</code> invokes <code>succ</code> to iterate through range
 274  *  elements. The following code uses class <code>Xs</code>, which is defined
 275  *  in the class-level documentation.
 276  *
 277  *     range = Xs.new(1)..Xs.new(10)
 278  *     range.step(2) {|x| puts x}
 279  *     range.step(3) {|x| puts x}
 280  *
 281  *  <em>produces:</em>
 282  *
 283  *      1 x
 284  *      3 xxx
 285  *      5 xxxxx
 286  *      7 xxxxxxx
 287  *      9 xxxxxxxxx
 288  *      1 x
 289  *      4 xxxx
 290  *      7 xxxxxxx
 291  *     10 xxxxxxxxxx
 292  */
 293
 294
 295 static VALUE
 296 range_step(int argc, VALUE *argv, VALUE range)
 297 {
 298     VALUE b, e, step, tmp;
 299
 300     RETURN_ENUMERATOR(range, argc, argv);
 301
 302     b = RANGE_BEG(range);
 303     e = RANGE_END(range);
 304     if (argc == 0) {
 305         step = INT2FIX(1);
 306     }
 307     else {
 308         rb_scan_args(argc, argv, "01", &step);
 309         if (!rb_obj_is_kind_of(step, rb_cNumeric)) {
 310             step = rb_to_int(step);
 311         }
 312         if (rb_funcall(step, '<', 1, INT2FIX(0))) {
 313             rb_raise(rb_eArgError, "step can't be negative");
 314         }
 315         else if (!rb_funcall(step, '>', 1, INT2FIX(0))) {
 316             rb_raise(rb_eArgError, "step can't be 0");
 317         }
 318     }
 319
 320     if (FIXNUM_P(b) && FIXNUM_P(e) && FIXNUM_P(step)) { /* fixnums are special */
 321         long end = FIX2LONG(e);
 322         long i, unit = FIX2LONG(step);
 323
 324         if (!EXCL(range))
 325             end += 1;
 326         i = FIX2LONG(b);
 327         while (i < end) {
 328             rb_yield(LONG2NUM(i));
 329             if (i + unit < i) break;
 330             i += unit;
 331         }
 332
 333     }
 334     else if (rb_obj_is_kind_of(b, rb_cNumeric) ||
 335              !NIL_P(rb_check_to_integer(b, "to_int")) ||
 336              !NIL_P(rb_check_to_integer(e, "to_int"))) {
 337         ID op = EXCL(range) ? '<' : rb_intern("<=");
 338
 339         while (RTEST(rb_funcall(b, op, 1, e))) {
 340             rb_yield(b);
 341             b = rb_funcall(b, '+', 1, step);
 342         }
 343     }
 344     else {
 345         tmp = rb_check_string_type(b);
 346
 347         if (!NIL_P(tmp)) {
 348             VALUE args[2], iter[2];
 349
 350             b = tmp;
 351             args[0] = e;
 352             args[1] = EXCL(range) ? Qtrue : Qfalse;
 353             iter[0] = INT2FIX(1);
 354             iter[1] = step;
 355             rb_block_call(b, rb_intern("upto"), 2, args, step_i, (VALUE)iter);
 356         }
 357         else {
 358             VALUE args[2];
 359
 360             if (!rb_respond_to(b, id_succ)) {
 361                 rb_raise(rb_eTypeError, "can't iterate from %s",
 362                          rb_obj_classname(b));
 363             }
 364             args[0] = INT2FIX(1);
 365             args[1] = step;
 366             range_each_func(range, step_i, args);
 367         }
 368     }
 369     return range;
 370 }
 371
 372 static VALUE
 373 each_i(VALUE v, void *arg)
 374 {
 375     rb_yield(v);
 376     return Qnil;
 377 }
 378
 379 /*
 380  *  call-seq:
 381  *     rng.each {| i | block } => rng
 382  *
 383  *  Iterates over the elements <i>rng</i>, passing each in turn to the
 384  *  block. You can only iterate if the start object of the range
 385  *  supports the +succ+ method (which means that you can't iterate over
 386  *  ranges of +Float+ objects).
 387  *
 388  *     (10..15).each do |n|
 389  *        print n, ' '
 390  *     end
 391  *
 392  *  <em>produces:</em>
 393  *
 394  *     10 11 12 13 14 15
 395  */
 396
 397 static VALUE
 398 range_each(VALUE range)
 399 {
 400     VALUE beg, end;
 401
 402     RETURN_ENUMERATOR(range, 0, 0);
 403
 404     beg = RANGE_BEG(range);
 405     end = RANGE_END(range);
 406
 407     if (!rb_respond_to(beg, id_succ)) {
 408         rb_raise(rb_eTypeError, "can't iterate from %s",
 409                  rb_obj_classname(beg));
 410     }
 411     if (FIXNUM_P(beg) && FIXNUM_P(end)) { /* fixnums are special */
 412         long lim = FIX2LONG(end);
 413         long i;
 414
 415         if (!EXCL(range))
 416             lim += 1;
 417         for (i = FIX2LONG(beg); i < lim; i++) {
 418             rb_yield(LONG2FIX(i));
 419         }
 420     }
 421     else if (TYPE(beg) == T_STRING) {
 422         VALUE args[2];
 423
 424         args[0] = end;
 425         args[1] = EXCL(range) ? Qtrue : Qfalse;
 426         rb_block_call(beg, rb_intern("upto"), 2, args, rb_yield, 0);
 427     }
 428     else {
 429         range_each_func(range, each_i, NULL);
 430     }
 431     return range;
 432 }
 433
 434 /*
 435  *  call-seq:
 436  *     rng.begin    => obj
 437  *
 438  *  Returns the first object in <i>rng</i>.
 439  */
 440
 441 static VALUE
 442 range_begin(VALUE range)
 443 {
 444     return RANGE_BEG(range);
 445 }
 446
 447
 448 /*
 449  *  call-seq:
 450  *     rng.end    => obj
 451  *
 452  *  Returns the object that defines the end of <i>rng</i>.
 453  *
 454  *     (1..10).end    #=> 10
 455  *     (1...10).end   #=> 10
 456  */
 457
 458
 459 static VALUE
 460 range_end(VALUE range)
 461 {
 462     return RANGE_END(range);
 463 }
 464
 465
 466 static VALUE
 467 first_i(VALUE i, VALUE *ary)
 468 {
 469     long n = NUM2LONG(ary[0]);
 470
 471     if (n <= 0) {
 472         rb_iter_break();
 473     }
 474     rb_ary_push(ary[1], i);
 475     n--;
 476     ary[0] = INT2NUM(n);
 477     return Qnil;
 478 }
 479
 480 /*
 481  *  call-seq:
 482  *     rng.first    => obj
 483  *     rng.first(n) => an_array
 484  *
 485  *  Returns the first object in <i>rng</i>, or the first +n+ elements.
 486  */
 487
 488 static VALUE
 489 range_first(int argc, VALUE *argv, VALUE range)
 490 {
 491     VALUE n, ary[2];
 492
 493     if (argc == 0) return RANGE_BEG(range);
 494
 495     rb_scan_args(argc, argv, "1", &n);
 496     ary[0] = n;
 497     ary[1] = rb_ary_new2(NUM2LONG(n));
 498     rb_block_call(range, rb_intern("each"), 0, 0, first_i, (VALUE)ary);
 499
 500     return ary[1];
 501 }
 502
 503
 504 /*
 505  *  call-seq:
 506  *     rng.last    => obj
 507  *     rng.last(n) => an_array
 508  *
 509  *  Returns the last object in <i>rng</i>, or the last +n+ elements.
 510  */
 511
 512 static VALUE
 513 range_last(int argc, VALUE *argv, VALUE range)
 514 {
 515     VALUE rb_ary_last(int, VALUE *, VALUE);
 516
 517     if (argc == 0) return RANGE_END(range);
 518     return rb_ary_last(argc, argv, rb_Array(range));
 519 }
 520
 521
 522 /*
 523  *  call-seq:
 524  *     rng.min                    => obj
 525  *     rng.min {| a,b | block }   => obj
 526  *
 527  *  Returns the minimum value in <i>rng</i>. The second uses
 528  *  the block to compare values.  Returns nil if the first
 529  *  value in range is larger than the last value.
 530  *
 531  */
 532
 533
 534 static VALUE
 535 range_min(VALUE range)
 536 {
 537     if (rb_block_given_p()) {
 538         return rb_call_super(0, 0);
 539     }
 540     else {
 541         VALUE b = RANGE_BEG(range);
 542         VALUE e = RANGE_END(range);
 543         int c = rb_cmpint(rb_funcall(b, id_cmp, 1, e), b, e);
 544
 545         if (c > 0 || (c == 0 && EXCL(range)))
 546             return Qnil;
 547         return b;
 548     }
 549 }
 550
 551 /*
 552  *  call-seq:
 553  *     rng.max                    => obj
 554  *     rng.max {| a,b | block }   => obj
 555  *
 556  *  Returns the maximum value in <i>rng</i>. The second uses
 557  *  the block to compare values.  Returns nil if the first
 558  *  value in range is larger than the last value.
 559  *
 560  */
 561
 562
 563 static VALUE
 564 range_max(VALUE range)
 565 {
 566     VALUE e = RANGE_END(range);
 567     int ip = FIXNUM_P(e) || rb_obj_is_kind_of(e, rb_cInteger);
 568
 569     if (rb_block_given_p() || (EXCL(range) && !ip)) {
 570         return rb_call_super(0, 0);
 571     }
 572     else {
 573         VALUE b = RANGE_BEG(range);
 574         int c = rb_cmpint(rb_funcall(b, id_cmp, 1, e), b, e);
 575
 576         if (c > 0)
 577             return Qnil;
 578         if (EXCL(range)) {
 579             if (c == 0) return Qnil;
 580             if (FIXNUM_P(e)) {
 581                 return LONG2NUM(FIX2LONG(e) - 1);
 582             }
 583             return rb_funcall(e, '-', 1, INT2FIX(1));
 584         }
 585         return e;
 586     }
 587 }
 588
 589 VALUE
 590 rb_range_beg_len(VALUE range, long *begp, long *lenp, long len, int err)
 591 {
 592     VALUE b, e;
 593     long beg, end, excl;
 594
 595     if (rb_obj_is_kind_of(range, rb_cRange)) {
 596         b = RANGE_BEG(range);
 597         e = RANGE_END(range);
 598         excl = EXCL(range);
 599     }
 600     else {
 601         if (!rb_respond_to(range, id_beg)) return Qfalse;
 602         if (!rb_respond_to(range, id_end)) return Qfalse;
 603         b = rb_funcall(range, id_beg, 0);
 604         e = rb_funcall(range, id_end, 0);
 605         excl = RTEST(rb_funcall(range, rb_intern("exclude_end?"), 0));
 606     }
 607     beg = NUM2LONG(b);
 608     end = NUM2LONG(e);
 609
 610     if (beg < 0) {
 611         beg += len;
 612         if (beg < 0)
 613             goto out_of_range;
 614     }
 615     if (err == 0 || err == 2) {
 616         if (beg > len)
 617             goto out_of_range;
 618         if (end > len)
 619             end = len;
 620     }
 621     if (end < 0)
 622         end += len;
 623     if (!excl)
 624         end++;                  /* include end point */
 625     len = end - beg;
 626     if (len < 0)
 627         len = 0;
 628
 629     *begp = beg;
 630     *lenp = len;
 631     return Qtrue;
 632
 633   out_of_range:
 634     if (err) {
 635         rb_raise(rb_eRangeError, "%ld..%s%ld out of range",
 636                  b, excl ? "." : "", e);
 637     }
 638     return Qnil;
 639 }
 640
 641 /*
 642  * call-seq:
 643  *   rng.to_s   => string
 644  *
 645  * Convert this range object to a printable form.
 646  */
 647
 648 static VALUE
 649 range_to_s(VALUE range)
 650 {
 651     VALUE str, str2;
 652
 653     str = rb_obj_as_string(RANGE_BEG(range));
 654     str2 = rb_obj_as_string(RANGE_END(range));
 655     str = rb_str_dup(str);
 656     rb_str_cat(str, "...", EXCL(range) ? 3 : 2);
 657     rb_str_append(str, str2);
 658     OBJ_INFECT(str, str2);
 659
 660     return str;
 661 }
 662
 663 /*
 664  * call-seq:
 665  *   rng.inspect  => string
 666  *
 667  * Convert this range object to a printable form (using
 668  * <code>inspect</code> to convert the start and end
 669  * objects).
 670  */
 671
 672
 673 static VALUE
 674 range_inspect(VALUE range)
 675 {
 676     VALUE str, str2;
 677
 678     str = rb_inspect(RANGE_BEG(range));
 679     str2 = rb_inspect(RANGE_END(range));
 680     str = rb_str_dup(str);
 681     rb_str_cat(str, "...", EXCL(range) ? 3 : 2);
 682     rb_str_append(str, str2);
 683     OBJ_INFECT(str, str2);
 684
 685     return str;
 686 }
 687
 688 /*
 689  *  call-seq:
 690  *     rng === obj       =>  true or false
 691  *
 692  *  Returns <code>true</code> if <i>obj</i> is an element of
 693  *  <i>rng</i>, <code>false</code> otherwise. Conveniently,
 694  *  <code>===</code> is the comparison operator used by
 695  *  <code>case</code> statements.
 696  *
 697  *     case 79
 698  *     when 1..50   then   print "low\n"
 699  *     when 51..75  then   print "medium\n"
 700  *     when 76..100 then   print "high\n"
 701  *     end
 702  *
 703  *  <em>produces:</em>
 704  *
 705  *     high
 706  */
 707
 708 static VALUE
 709 range_eqq(VALUE range, VALUE val)
 710 {
 711     return rb_funcall(range, rb_intern("include?"), 1, val);
 712 }
 713
 714
 715 /*
 716  *  call-seq:
 717  *     rng.member?(val)  =>  true or false
 718  *     rng.include?(val) =>  true or false
 719  *
 720  *  Returns <code>true</code> if <i>obj</i> is an element of
 721  *  <i>rng</i>, <code>false</code> otherwise.  If beg and end are
 722  *  numeric, comparison is done according magnitude of values.
 723  *
 724  *     ("a".."z").include?("g")  # => true
 725  *     ("a".."z").include?("A")  # => false
 726  */
 727
 728 static VALUE
 729 range_include(VALUE range, VALUE val)
 730 {
 731     VALUE beg = RANGE_BEG(range);
 732     VALUE end = RANGE_END(range);
 733     int nv = FIXNUM_P(beg) || FIXNUM_P(end) ||
 734              rb_obj_is_kind_of(beg, rb_cNumeric) ||
 735              rb_obj_is_kind_of(end, rb_cNumeric);
 736
 737     if (nv ||
 738         !NIL_P(rb_check_to_integer(beg, "to_int")) ||
 739         !NIL_P(rb_check_to_integer(end, "to_int"))) {
 740         if (r_le(beg, val)) {
 741             if (EXCL(range)) {
 742                 if (r_lt(val, end))
 743                     return Qtrue;
 744             }
 745             else {
 746                 if (r_le(val, end))
 747                     return Qtrue;
 748             }
 749         }
 750         return Qfalse;
 751     }
 752     else if (TYPE(beg) == T_STRING && TYPE(end) == T_STRING &&
 753              RSTRING_LEN(beg) == 1 && RSTRING_LEN(end) == 1) {
 754         if (NIL_P(val)) return Qfalse;
 755         if (TYPE(val) == T_STRING) {
 756             if (RSTRING_LEN(val) == 0 || RSTRING_LEN(val) > 1)
 757                 return Qfalse;
 758             else {
 759                 char b = RSTRING_PTR(beg)[0];
 760                 char e = RSTRING_PTR(end)[0];
 761                 char v = RSTRING_PTR(val)[0];
 762
 763                 if (ISASCII(b) && ISASCII(e) && ISASCII(v)) {
 764                     if (b <= v && v < e) return Qtrue;
 765                     if (!EXCL(range) && v == e) return Qtrue;
 766                     return Qfalse;
 767                 }
 768             }
 769         }
 770     }
 771     /* TODO: ruby_frame->this_func = rb_intern("include?"); */
 772     return rb_call_super(1, &val);
 773 }
 774
 775
 776 /*
 777  *  call-seq:
 778  *     rng.cover?(val)  =>  true or false
 779  *
 780  *  Returns <code>true</code> if <i>obj</i> is between beg and end,
 781  *  i.e <code>beg <= obj <= end</code> (or <i>end</i> exclusive when
 782  *  <code>exclude_end?</code> is true).
 783  *
 784  *     ("a".."z").cover?("c")    #=> true
 785  *     ("a".."z").cover?("5")    #=> false
 786  */
 787
 788 static VALUE
 789 range_cover(VALUE range, VALUE val)
 790 {
 791     VALUE beg, end;
 792
 793     beg = RANGE_BEG(range);
 794     end = RANGE_END(range);
 795     if (r_le(beg, val)) {
 796         if (EXCL(range)) {
 797             if (r_lt(val, end))
 798                 return Qtrue;
 799         }
 800         else {
 801             if (r_le(val, end))
 802                 return Qtrue;
 803         }
 804     }
 805     return Qfalse;
 806 }
 807
 808 static VALUE
 809 range_dumper(VALUE range)
 810 {
 811     VALUE v;
 812     NEWOBJ(m, struct RObject);
 813     OBJSETUP(m, rb_cObject, T_OBJECT);
 814
 815     v = (VALUE)m;
 816
 817     rb_ivar_set(v, id_excl, RANGE_EXCL(range));
 818     rb_ivar_set(v, id_beg, RANGE_BEG(range));
 819     rb_ivar_set(v, id_end, RANGE_END(range));
 820     return v;
 821 }
 822
 823 static VALUE
 824 range_loader(VALUE range, VALUE obj)
 825 {
 826     if (TYPE(obj) != T_OBJECT || RBASIC(obj)->klass != rb_cObject) {
 827         rb_raise(rb_eTypeError, "not a dumped range object");
 828     }
 829
 830     RSTRUCT(range)->as.ary[0] = rb_ivar_get(obj, id_beg);
 831     RSTRUCT(range)->as.ary[1] = rb_ivar_get(obj, id_end);
 832     RSTRUCT(range)->as.ary[2] = rb_ivar_get(obj, id_excl);
 833     return range;
 834 }
 835
 836 static VALUE
 837 range_alloc(VALUE klass)
 838 {
 839   /* rb_struct_alloc_noinit itself should not be used because
 840    * rb_marshal_define_compat uses equality of allocaiton function */
 841     return rb_struct_alloc_noinit(klass);
 842 }
 843
 844 /*  A <code>Range</code> represents an interval---a set of values with a
 845  *  start and an end. Ranges may be constructed using the
 846  *  <em>s</em><code>..</code><em>e</em> and
 847  *  <em>s</em><code>...</code><em>e</em> literals, or with
 848  *  <code>Range::new</code>. Ranges constructed using <code>..</code>
 849  *  run from the start to the end inclusively. Those created using
 850  *  <code>...</code> exclude the end value. When used as an iterator,
 851  *  ranges return each value in the sequence.
 852  *
 853  *     (-1..-5).to_a      #=> []
 854  *     (-5..-1).to_a      #=> [-5, -4, -3, -2, -1]
 855  *     ('a'..'e').to_a    #=> ["a", "b", "c", "d", "e"]
 856  *     ('a'...'e').to_a   #=> ["a", "b", "c", "d"]
 857  *
 858  *  Ranges can be constructed using objects of any type, as long as the
 859  *  objects can be compared using their <code><=></code> operator and
 860  *  they support the <code>succ</code> method to return the next object
 861  *  in sequence.
 862  *
 863  *     class Xs                # represent a string of 'x's
 864  *       include Comparable
 865  *       attr :length
 866  *       def initialize(n)
 867  *         @length = n
 868  *       end
 869  *       def succ
 870  *         Xs.new(@length + 1)
 871  *       end
 872  *       def <=>(other)
 873  *         @length <=> other.length
 874  *       end
 875  *       def to_s
 876  *         sprintf "%2d #{inspect}", @length
 877  *       end
 878  *       def inspect
 879  *         'x' * @length
 880  *       end
 881  *     end
 882  *
 883  *     r = Xs.new(3)..Xs.new(6)   #=> xxx..xxxxxx
 884  *     r.to_a                     #=> [xxx, xxxx, xxxxx, xxxxxx]
 885  *     r.member?(Xs.new(5))       #=> true
 886  *
 887  *  In the previous code example, class <code>Xs</code> includes the
 888  *  <code>Comparable</code> module. This is because
 889  *  <code>Enumerable#member?</code> checks for equality using
 890  *  <code>==</code>. Including <code>Comparable</code> ensures that the
 891  *  <code>==</code> method is defined in terms of the <code><=></code>
 892  *  method implemented in <code>Xs</code>.
 893  *
 894  */
 895
 896 void
 897 Init_Range(void)
 898 {
 899     id_cmp = rb_intern("<=>");
 900     id_succ = rb_intern("succ");
 901     id_beg = rb_intern("begin");
 902     id_end = rb_intern("end");
 903     id_excl = rb_intern("excl");
 904
 905     rb_cRange = rb_struct_define_without_accessor(
 906         "Range", rb_cObject, range_alloc,
 907         "begin", "end", "excl", NULL);
 908
 909     rb_include_module(rb_cRange, rb_mEnumerable);
 910     rb_marshal_define_compat(rb_cRange, rb_cObject, range_dumper, range_loader);
 911     rb_define_method(rb_cRange, "initialize", range_initialize, -1);
 912     rb_define_method(rb_cRange, "==", range_eq, 1);
 913     rb_define_method(rb_cRange, "===", range_eqq, 1);
 914     rb_define_method(rb_cRange, "eql?", range_eql, 1);
 915     rb_define_method(rb_cRange, "hash", range_hash, 0);
 916     rb_define_method(rb_cRange, "each", range_each, 0);
 917     rb_define_method(rb_cRange, "step", range_step, -1);
 918     rb_define_method(rb_cRange, "begin", range_begin, 0);
 919     rb_define_method(rb_cRange, "end", range_end, 0);
 920     rb_define_method(rb_cRange, "first", range_first, -1);
 921     rb_define_method(rb_cRange, "last", range_last, -1);
 922     rb_define_method(rb_cRange, "min", range_min, 0);
 923     rb_define_method(rb_cRange, "max", range_max, 0);
 924     rb_define_method(rb_cRange, "to_s", range_to_s, 0);
 925     rb_define_method(rb_cRange, "inspect", range_inspect, 0);
 926
 927     rb_define_method(rb_cRange, "exclude_end?", range_exclude_end_p, 0);
 928
 929     rb_define_method(rb_cRange, "member?", range_include, 1);
 930     rb_define_method(rb_cRange, "include?", range_include, 1);
 931     rb_define_method(rb_cRange, "cover?", range_cover, 1);
 932 }