universal.c

   1 /*    universal.c
   2  *
   3  *    Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   4  *    by Larry Wall and others
   5  *
   6  *    You may distribute under the terms of either the GNU General Public
   7  *    License or the Artistic License, as specified in the README file.
   8  *
   9  */
  10
  11 /*
  12  * "The roots of those mountains must be roots indeed; there must be
  13  * great secrets buried there which have not been discovered since the
  14  * beginning." --Gandalf, relating Gollum's story
  15  */
  16
  17 #include "EXTERN.h"
  18 #define PERL_IN_UNIVERSAL_C
  19 #include "perl.h"
  20
  21 #ifdef USE_PERLIO
  22 #include "perliol.h" /* For the PERLIO_F_XXX */
  23 #endif
  24
  25 /*
  26  * Contributed by Graham Barr  <Graham.Barr@tiuk.ti.com>
  27  * The main guts of traverse_isa was actually copied from gv_fetchmeth
  28  */
  29
  30 STATIC SV *
  31 S_isa_lookup(pTHX_ HV *stash, const char *name, HV* name_stash,
  32              int len, int level)
  33 {
  34     AV* av;
  35     GV* gv;
  36     GV** gvp;
  37     HV* hv = Nullhv;
  38     SV* subgen = Nullsv;
  39
  40     /* A stash/class can go by many names (ie. User == main::User), so
  41        we compare the stash itself just in case */
  42     if (name_stash && (stash == name_stash))
  43         return &PL_sv_yes;
  44
  45     if (strEQ(HvNAME(stash), name))
  46         return &PL_sv_yes;
  47
  48     if (strEQ(name, "UNIVERSAL"))
  49         return &PL_sv_yes;
  50
  51     if (level > 100)
  52         Perl_croak(aTHX_ "Recursive inheritance detected in package '%s'",
  53                    HvNAME(stash));
  54
  55     gvp = (GV**)hv_fetch(stash, "::ISA::CACHE::", 14, FALSE);
  56
  57     if (gvp && (gv = *gvp) != (GV*)&PL_sv_undef && (subgen = GvSV(gv))
  58         && (hv = GvHV(gv)))
  59     {
  60         if (SvIV(subgen) == (IV)PL_sub_generation) {
  61             SV* sv;
  62             SV** svp = (SV**)hv_fetch(hv, name, len, FALSE);
  63             if (svp && (sv = *svp) != (SV*)&PL_sv_undef) {
  64                 DEBUG_o( Perl_deb(aTHX_ "Using cached ISA %s for package %s\n",
  65                                   name, HvNAME(stash)) );
  66                 return sv;
  67             }
  68         }
  69         else {
  70             DEBUG_o( Perl_deb(aTHX_ "ISA Cache in package %s is stale\n",
  71                               HvNAME(stash)) );
  72             hv_clear(hv);
  73             sv_setiv(subgen, PL_sub_generation);
  74         }
  75     }
  76
  77     gvp = (GV**)hv_fetch(stash,"ISA",3,FALSE);
  78
  79     if (gvp && (gv = *gvp) != (GV*)&PL_sv_undef && (av = GvAV(gv))) {
  80         if (!hv || !subgen) {
  81             gvp = (GV**)hv_fetch(stash, "::ISA::CACHE::", 14, TRUE);
  82
  83             gv = *gvp;
  84
  85             if (SvTYPE(gv) != SVt_PVGV)
  86                 gv_init(gv, stash, "::ISA::CACHE::", 14, TRUE);
  87
  88             if (!hv)
  89                 hv = GvHVn(gv);
  90             if (!subgen) {
  91                 subgen = newSViv(PL_sub_generation);
  92                 GvSV(gv) = subgen;
  93             }
  94         }
  95         if (hv) {
  96             SV** svp = AvARRAY(av);
  97             /* NOTE: No support for tied ISA */
  98             I32 items = AvFILLp(av) + 1;
  99             while (items--) {
 100                 SV* sv = *svp++;
 101                 HV* basestash = gv_stashsv(sv, FALSE);
 102                 if (!basestash) {
 103                     if (ckWARN(WARN_MISC))
 104                         Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
 105                              "Can't locate package %"SVf" for @%s::ISA",
 106                             sv, HvNAME(stash));
 107                     continue;
 108                 }
 109                 if (&PL_sv_yes == isa_lookup(basestash, name, name_stash,
 110                                              len, level + 1)) {
 111                     (void)hv_store(hv,name,len,&PL_sv_yes,0);
 112                     return &PL_sv_yes;
 113                 }
 114             }
 115             (void)hv_store(hv,name,len,&PL_sv_no,0);
 116         }
 117     }
 118     return &PL_sv_no;
 119 }
 120
 121 /*
 122 =head1 SV Manipulation Functions
 123
 124 =for apidoc sv_derived_from
 125
 126 Returns a boolean indicating whether the SV is derived from the specified
 127 class.  This is the function that implements C<UNIVERSAL::isa>.  It works
 128 for class names as well as for objects.
 129
 130 =cut
 131 */
 132
 133 bool
 134 Perl_sv_derived_from(pTHX_ SV *sv, const char *name)
 135 {
 136     char *type;
 137     HV *stash;
 138     HV *name_stash;
 139
 140     stash = Nullhv;
 141     type = Nullch;
 142
 143     if (SvGMAGICAL(sv))
 144         mg_get(sv) ;
 145
 146     if (SvROK(sv)) {
 147         sv = SvRV(sv);
 148         type = sv_reftype(sv,0);
 149         if (SvOBJECT(sv))
 150             stash = SvSTASH(sv);
 151     }
 152     else {
 153         stash = gv_stashsv(sv, FALSE);
 154     }
 155
 156     name_stash = gv_stashpv(name, FALSE);
 157
 158     return (type && strEQ(type,name)) ||
 159             (stash && isa_lookup(stash, name, name_stash, strlen(name), 0)
 160              == &PL_sv_yes)
 161         ? TRUE
 162         : FALSE ;
 163 }
 164
 165 #include "XSUB.h"
 166
 167 void XS_UNIVERSAL_isa(pTHX_ CV *cv);
 168 void XS_UNIVERSAL_can(pTHX_ CV *cv);
 169 void XS_UNIVERSAL_VERSION(pTHX_ CV *cv);
 170 XS(XS_version_new);
 171 XS(XS_version_stringify);
 172 XS(XS_version_numify);
 173 XS(XS_version_vcmp);
 174 XS(XS_version_boolean);
 175 XS(XS_version_noop);
 176 XS(XS_version_is_alpha);
 177 XS(XS_version_qv);
 178 XS(XS_utf8_is_utf8);
 179 XS(XS_utf8_valid);
 180 XS(XS_utf8_encode);
 181 XS(XS_utf8_decode);
 182 XS(XS_utf8_upgrade);
 183 XS(XS_utf8_downgrade);
 184 XS(XS_utf8_unicode_to_native);
 185 XS(XS_utf8_native_to_unicode);
 186 XS(XS_Internals_SvREADONLY);
 187 XS(XS_Internals_SvREFCNT);
 188 XS(XS_Internals_hv_clear_placehold);
 189 XS(XS_PerlIO_get_layers);
 190 XS(XS_Regexp_DESTROY);
 191 XS(XS_Internals_hash_seed);
 192 XS(XS_Internals_rehash_seed);
 193 XS(XS_Internals_HvREHASH);
 194
 195 void
 196 Perl_boot_core_UNIVERSAL(pTHX)
 197 {
 198     char *file = __FILE__;
 199
 200     newXS("UNIVERSAL::isa",             XS_UNIVERSAL_isa,         file);
 201     newXS("UNIVERSAL::can",             XS_UNIVERSAL_can,         file);
 202     newXS("UNIVERSAL::VERSION",         XS_UNIVERSAL_VERSION,     file);
 203     {
 204         /* register the overloading (type 'A') magic */
 205         PL_amagic_generation++;
 206         /* Make it findable via fetchmethod */
 207         newXS("version::()", XS_version_noop, file);
 208         newXS("version::new", XS_version_new, file);
 209         newXS("version::(\"\"", XS_version_stringify, file);
 210         newXS("version::stringify", XS_version_stringify, file);
 211         newXS("version::(0+", XS_version_numify, file);
 212         newXS("version::numify", XS_version_numify, file);
 213         newXS("version::(cmp", XS_version_vcmp, file);
 214         newXS("version::(<=>", XS_version_vcmp, file);
 215         newXS("version::vcmp", XS_version_vcmp, file);
 216         newXS("version::(bool", XS_version_boolean, file);
 217         newXS("version::boolean", XS_version_boolean, file);
 218         newXS("version::(nomethod", XS_version_noop, file);
 219         newXS("version::noop", XS_version_noop, file);
 220         newXS("version::is_alpha", XS_version_is_alpha, file);
 221         newXS("version::qv", XS_version_qv, file);
 222     }
 223     newXS("utf8::is_utf8", XS_utf8_is_utf8, file);
 224     newXS("utf8::valid", XS_utf8_valid, file);
 225     newXS("utf8::encode", XS_utf8_encode, file);
 226     newXS("utf8::decode", XS_utf8_decode, file);
 227     newXS("utf8::upgrade", XS_utf8_upgrade, file);
 228     newXS("utf8::downgrade", XS_utf8_downgrade, file);
 229     newXS("utf8::native_to_unicode", XS_utf8_native_to_unicode, file);
 230     newXS("utf8::unicode_to_native", XS_utf8_unicode_to_native, file);
 231     newXSproto("Internals::SvREADONLY",XS_Internals_SvREADONLY, file, "\\[$%@];$");
 232     newXSproto("Internals::SvREFCNT",XS_Internals_SvREFCNT, file, "\\[$%@];$");
 233     newXSproto("Internals::hv_clear_placeholders",
 234                XS_Internals_hv_clear_placehold, file, "\\%");
 235     newXSproto("PerlIO::get_layers",
 236                XS_PerlIO_get_layers, file, "*;@");
 237     newXS("Regexp::DESTROY", XS_Regexp_DESTROY, file);
 238     newXSproto("Internals::hash_seed",XS_Internals_hash_seed, file, "");
 239     newXSproto("Internals::rehash_seed",XS_Internals_rehash_seed, file, "");
 240     newXSproto("Internals::HvREHASH", XS_Internals_HvREHASH, file, "\\%");
 241 }
 242
 243
 244 XS(XS_UNIVERSAL_isa)
 245 {
 246     dXSARGS;
 247     SV *sv;
 248     char *name;
 249     STRLEN n_a;
 250
 251     if (items != 2)
 252         Perl_croak(aTHX_ "Usage: UNIVERSAL::isa(reference, kind)");
 253
 254     sv = ST(0);
 255
 256     if (SvGMAGICAL(sv))
 257         mg_get(sv);
 258
 259     if (!SvOK(sv) || !(SvROK(sv) || (SvPOK(sv) && SvCUR(sv))
 260                 || (SvGMAGICAL(sv) && SvPOKp(sv) && SvCUR(sv))))
 261         XSRETURN_UNDEF;
 262
 263     name = (char *)SvPV(ST(1),n_a);
 264
 265     ST(0) = boolSV(sv_derived_from(sv, name));
 266     XSRETURN(1);
 267 }
 268
 269 XS(XS_UNIVERSAL_can)
 270 {
 271     dXSARGS;
 272     SV   *sv;
 273     char *name;
 274     SV   *rv;
 275     HV   *pkg = NULL;
 276     STRLEN n_a;
 277
 278     if (items != 2)
 279         Perl_croak(aTHX_ "Usage: UNIVERSAL::can(object-ref, method)");
 280
 281     sv = ST(0);
 282
 283     if (SvGMAGICAL(sv))
 284         mg_get(sv);
 285
 286     if (!SvOK(sv) || !(SvROK(sv) || (SvPOK(sv) && SvCUR(sv))
 287                 || (SvGMAGICAL(sv) && SvPOKp(sv) && SvCUR(sv))))
 288         XSRETURN_UNDEF;
 289
 290     name = (char *)SvPV(ST(1),n_a);
 291     rv = &PL_sv_undef;
 292
 293     if (SvROK(sv)) {
 294         sv = (SV*)SvRV(sv);
 295         if (SvOBJECT(sv))
 296             pkg = SvSTASH(sv);
 297     }
 298     else {
 299         pkg = gv_stashsv(sv, FALSE);
 300     }
 301
 302     if (pkg) {
 303         GV *gv = gv_fetchmethod_autoload(pkg, name, FALSE);
 304         if (gv && isGV(gv))
 305             rv = sv_2mortal(newRV((SV*)GvCV(gv)));
 306     }
 307
 308     ST(0) = rv;
 309     XSRETURN(1);
 310 }
 311
 312 XS(XS_UNIVERSAL_VERSION)
 313 {
 314     dXSARGS;
 315     HV *pkg;
 316     GV **gvp;
 317     GV *gv;
 318     SV *sv;
 319     char *undef;
 320
 321     if (SvROK(ST(0))) {
 322         sv = (SV*)SvRV(ST(0));
 323         if (!SvOBJECT(sv))
 324             Perl_croak(aTHX_ "Cannot find version of an unblessed reference");
 325         pkg = SvSTASH(sv);
 326     }
 327     else {
 328         pkg = gv_stashsv(ST(0), FALSE);
 329     }
 330
 331     gvp = pkg ? (GV**)hv_fetch(pkg,"VERSION",7,FALSE) : Null(GV**);
 332
 333     if (gvp && isGV(gv = *gvp) && SvOK(sv = GvSV(gv))) {
 334         SV *nsv = sv_newmortal();
 335         sv_setsv(nsv, sv);
 336         sv = nsv;
 337         if ( !sv_derived_from(sv, "version"))
 338             upg_version(sv);
 339         undef = Nullch;
 340     }
 341     else {
 342         sv = (SV*)&PL_sv_undef;
 343         undef = "(undef)";
 344     }
 345
 346     if (items > 1) {
 347         STRLEN len;
 348         SV *req = ST(1);
 349
 350         if (undef) {
 351              if (pkg)
 352                   Perl_croak(aTHX_
 353                              "%s does not define $%s::VERSION--version check failed",
 354                              HvNAME(pkg), HvNAME(pkg));
 355              else {
 356                   char *str = SvPVx(ST(0), len);
 357
 358                   Perl_croak(aTHX_
 359                              "%s defines neither package nor VERSION--version check failed", str);
 360              }
 361         }
 362
 363         if ( !sv_derived_from(req, "version")) {
 364             /* req may very well be R/O, so create a new object */
 365             SV *nsv = sv_newmortal();
 366             sv_setsv(nsv, req);
 367             req = nsv;
 368             upg_version(req);
 369         }
 370
 371         if ( vcmp( req, sv ) > 0 )
 372             Perl_croak(aTHX_
 373                 "%s version %"SVf" required--this is only version %"SVf,
 374                 HvNAME(pkg), req, sv);
 375     }
 376
 377     ST(0) = sv;
 378
 379     XSRETURN(1);
 380 }
 381
 382 XS(XS_version_new)
 383 {
 384     dXSARGS;
 385     if (items > 3)
 386         Perl_croak(aTHX_ "Usage: version::new(class, version)");
 387     SP -= items;
 388     {
 389         char *  class = (char *)SvPV_nolen(ST(0));
 390         SV *vs = ST(1);
 391         SV *rv;
 392         if (items == 3 )
 393         {
 394             vs = sv_newmortal();
 395             Perl_sv_setpvf(aTHX_ vs,"v%s",SvPV_nolen(ST(2)));
 396         }
 397
 398         rv = new_version(vs);
 399         if ( strcmp(class,"version") != 0 ) /* inherited new() */
 400             sv_bless(rv, gv_stashpv(class,TRUE));
 401
 402         PUSHs(sv_2mortal(rv));
 403         PUTBACK;
 404         return;
 405     }
 406 }
 407
 408 XS(XS_version_stringify)
 409 {
 410      dXSARGS;
 411      if (items < 1)
 412           Perl_croak(aTHX_ "Usage: version::stringify(lobj, ...)");
 413      SP -= items;
 414      {
 415           SV *  lobj;
 416
 417           if (sv_derived_from(ST(0), "version")) {
 418                SV *tmp = SvRV(ST(0));
 419                lobj = tmp;
 420           }
 421           else
 422                Perl_croak(aTHX_ "lobj is not of type version");
 423
 424           PUSHs(sv_2mortal(vstringify(lobj)));
 425
 426           PUTBACK;
 427           return;
 428      }
 429 }
 430
 431 XS(XS_version_numify)
 432 {
 433      dXSARGS;
 434      if (items < 1)
 435           Perl_croak(aTHX_ "Usage: version::numify(lobj, ...)");
 436      SP -= items;
 437      {
 438           SV *  lobj;
 439
 440           if (sv_derived_from(ST(0), "version")) {
 441                SV *tmp = SvRV(ST(0));
 442                lobj = tmp;
 443           }
 444           else
 445                Perl_croak(aTHX_ "lobj is not of type version");
 446
 447           PUSHs(sv_2mortal(vnumify(lobj)));
 448
 449           PUTBACK;
 450           return;
 451      }
 452 }
 453
 454 XS(XS_version_vcmp)
 455 {
 456      dXSARGS;
 457      if (items < 1)
 458           Perl_croak(aTHX_ "Usage: version::vcmp(lobj, ...)");
 459      SP -= items;
 460      {
 461           SV *  lobj;
 462
 463           if (sv_derived_from(ST(0), "version")) {
 464                SV *tmp = SvRV(ST(0));
 465                lobj = tmp;
 466           }
 467           else
 468                Perl_croak(aTHX_ "lobj is not of type version");
 469
 470           {
 471                SV       *rs;
 472                SV       *rvs;
 473                SV * robj = ST(1);
 474                IV        swap = (IV)SvIV(ST(2));
 475
 476                if ( ! sv_derived_from(robj, "version") )
 477                {
 478                     robj = new_version(robj);
 479                }
 480                rvs = SvRV(robj);
 481
 482                if ( swap )
 483                {
 484                     rs = newSViv(vcmp(rvs,lobj));
 485                }
 486                else
 487                {
 488                     rs = newSViv(vcmp(lobj,rvs));
 489                }
 490
 491                PUSHs(sv_2mortal(rs));
 492           }
 493
 494           PUTBACK;
 495           return;
 496      }
 497 }
 498
 499 XS(XS_version_boolean)
 500 {
 501      dXSARGS;
 502      if (items < 1)
 503           Perl_croak(aTHX_ "Usage: version::boolean(lobj, ...)");
 504      SP -= items;
 505      {
 506           SV *  lobj;
 507
 508           if (sv_derived_from(ST(0), "version")) {
 509                SV *tmp = SvRV(ST(0));
 510                lobj = tmp;
 511           }
 512           else
 513                Perl_croak(aTHX_ "lobj is not of type version");
 514
 515           {
 516                SV       *rs;
 517                rs = newSViv( vcmp(lobj,new_version(newSVpvn("0",1))) );
 518                PUSHs(sv_2mortal(rs));
 519           }
 520
 521           PUTBACK;
 522           return;
 523      }
 524 }
 525
 526 XS(XS_version_noop)
 527 {
 528      dXSARGS;
 529      if (items < 1)
 530           Perl_croak(aTHX_ "Usage: version::noop(lobj, ...)");
 531      {
 532           SV *  lobj;
 533
 534           if (sv_derived_from(ST(0), "version")) {
 535                SV *tmp = SvRV(ST(0));
 536                lobj = tmp;
 537           }
 538           else
 539                Perl_croak(aTHX_ "lobj is not of type version");
 540
 541           {
 542                Perl_croak(aTHX_ "operation not supported with version object");
 543           }
 544
 545      }
 546      XSRETURN_EMPTY;
 547 }
 548
 549 XS(XS_version_is_alpha)
 550 {
 551     dXSARGS;
 552     if (items != 1)
 553         Perl_croak(aTHX_ "Usage: version::is_alpha(lobj)");
 554     SP -= items;
 555     {
 556         SV *lobj;
 557
 558         if (sv_derived_from(ST(0), "version")) {
 559                 SV *tmp = SvRV(ST(0));
 560                 lobj = tmp;
 561         }
 562         else
 563                 Perl_croak(aTHX_ "lobj is not of type version");
 564 {
 565     I32 len = av_len((AV *)lobj);
 566     I32 digit = SvIVX(*av_fetch((AV *)lobj, len, 0));
 567     if ( digit < 0 )
 568         XSRETURN_YES;
 569     else
 570         XSRETURN_NO;
 571 }
 572         PUTBACK;
 573         return;
 574     }
 575 }
 576
 577 XS(XS_version_qv)
 578 {
 579     dXSARGS;
 580     if (items != 1)
 581         Perl_croak(aTHX_ "Usage: version::qv(ver)");
 582     SP -= items;
 583     {
 584         SV *    ver = ST(0);
 585         if ( !SvVOK(ver) ) /* only need to do with if not already v-string */
 586         {
 587             SV *vs = sv_newmortal();
 588             char *version;
 589             if ( SvNOK(ver) ) /* may get too much accuracy */
 590             {
 591                 char tbuf[64];
 592                 sprintf(tbuf,"%.9"NVgf, SvNVX(ver));
 593                 version = savepv(tbuf);
 594             }
 595             else
 596             {
 597                 version = savepv(SvPV_nolen(ver));
 598             }
 599             (void)scan_version(version,vs,TRUE);
 600             Safefree(version);
 601
 602             PUSHs(vs);
 603         }
 604         else
 605         {
 606             PUSHs(sv_2mortal(new_version(ver)));
 607         }
 608
 609         PUTBACK;
 610         return;
 611     }
 612 }
 613
 614 XS(XS_utf8_is_utf8)
 615 {
 616      dXSARGS;
 617      if (items != 1)
 618           Perl_croak(aTHX_ "Usage: utf8::is_utf8(sv)");
 619      {
 620           SV *  sv = ST(0);
 621           {
 622                if (SvUTF8(sv))
 623                     XSRETURN_YES;
 624                else
 625                     XSRETURN_NO;
 626           }
 627      }
 628      XSRETURN_EMPTY;
 629 }
 630
 631 XS(XS_utf8_valid)
 632 {
 633      dXSARGS;
 634      if (items != 1)
 635           Perl_croak(aTHX_ "Usage: utf8::valid(sv)");
 636      {
 637           SV *  sv = ST(0);
 638           {
 639                STRLEN len;
 640                char *s = SvPV(sv,len);
 641                if (!SvUTF8(sv) || is_utf8_string((U8*)s,len))
 642                     XSRETURN_YES;
 643                else
 644                     XSRETURN_NO;
 645           }
 646      }
 647      XSRETURN_EMPTY;
 648 }
 649
 650 XS(XS_utf8_encode)
 651 {
 652     dXSARGS;
 653     if (items != 1)
 654         Perl_croak(aTHX_ "Usage: utf8::encode(sv)");
 655     {
 656         SV *    sv = ST(0);
 657
 658         sv_utf8_encode(sv);
 659     }
 660     XSRETURN_EMPTY;
 661 }
 662
 663 XS(XS_utf8_decode)
 664 {
 665     dXSARGS;
 666     if (items != 1)
 667         Perl_croak(aTHX_ "Usage: utf8::decode(sv)");
 668     {
 669         SV *    sv = ST(0);
 670         bool    RETVAL;
 671
 672         RETVAL = sv_utf8_decode(sv);
 673         ST(0) = boolSV(RETVAL);
 674         sv_2mortal(ST(0));
 675     }
 676     XSRETURN(1);
 677 }
 678
 679 XS(XS_utf8_upgrade)
 680 {
 681     dXSARGS;
 682     if (items != 1)
 683         Perl_croak(aTHX_ "Usage: utf8::upgrade(sv)");
 684     {
 685         SV *    sv = ST(0);
 686         STRLEN  RETVAL;
 687         dXSTARG;
 688
 689         RETVAL = sv_utf8_upgrade(sv);
 690         XSprePUSH; PUSHi((IV)RETVAL);
 691     }
 692     XSRETURN(1);
 693 }
 694
 695 XS(XS_utf8_downgrade)
 696 {
 697     dXSARGS;
 698     if (items < 1 || items > 2)
 699         Perl_croak(aTHX_ "Usage: utf8::downgrade(sv, failok=0)");
 700     {
 701         SV *    sv = ST(0);
 702         bool    failok;
 703         bool    RETVAL;
 704
 705         if (items < 2)
 706             failok = 0;
 707         else {
 708             failok = (int)SvIV(ST(1));
 709         }
 710
 711         RETVAL = sv_utf8_downgrade(sv, failok);
 712         ST(0) = boolSV(RETVAL);
 713         sv_2mortal(ST(0));
 714     }
 715     XSRETURN(1);
 716 }
 717
 718 XS(XS_utf8_native_to_unicode)
 719 {
 720  dXSARGS;
 721  UV uv = SvUV(ST(0));
 722
 723  if (items > 1)
 724      Perl_croak(aTHX_ "Usage: utf8::native_to_unicode(sv)");
 725
 726  ST(0) = sv_2mortal(newSViv(NATIVE_TO_UNI(uv)));
 727  XSRETURN(1);
 728 }
 729
 730 XS(XS_utf8_unicode_to_native)
 731 {
 732  dXSARGS;
 733  UV uv = SvUV(ST(0));
 734
 735  if (items > 1)
 736      Perl_croak(aTHX_ "Usage: utf8::unicode_to_native(sv)");
 737
 738  ST(0) = sv_2mortal(newSViv(UNI_TO_NATIVE(uv)));
 739  XSRETURN(1);
 740 }
 741
 742 XS(XS_Internals_SvREADONLY)     /* This is dangerous stuff. */
 743 {
 744     dXSARGS;
 745     SV *sv = SvRV(ST(0));
 746     if (items == 1) {
 747          if (SvREADONLY(sv))
 748              XSRETURN_YES;
 749          else
 750              XSRETURN_NO;
 751     }
 752     else if (items == 2) {
 753         if (SvTRUE(ST(1))) {
 754             SvREADONLY_on(sv);
 755             XSRETURN_YES;
 756         }
 757         else {
 758             /* I hope you really know what you are doing. */
 759             SvREADONLY_off(sv);
 760             XSRETURN_NO;
 761         }
 762     }
 763     XSRETURN_UNDEF; /* Can't happen. */
 764 }
 765
 766 XS(XS_Internals_SvREFCNT)       /* This is dangerous stuff. */
 767 {
 768     dXSARGS;
 769     SV *sv = SvRV(ST(0));
 770     if (items == 1)
 771          XSRETURN_IV(SvREFCNT(sv) - 1); /* Minus the ref created for us. */
 772     else if (items == 2) {
 773          /* I hope you really know what you are doing. */
 774          SvREFCNT(sv) = SvIV(ST(1));
 775          XSRETURN_IV(SvREFCNT(sv));
 776     }
 777     XSRETURN_UNDEF; /* Can't happen. */
 778 }
 779
 780 XS(XS_Internals_hv_clear_placehold)
 781 {
 782     dXSARGS;
 783     HV *hv = (HV *) SvRV(ST(0));
 784     if (items != 1)
 785         Perl_croak(aTHX_ "Usage: UNIVERSAL::hv_clear_placeholders(hv)");
 786     hv_clear_placeholders(hv);
 787     XSRETURN(0);
 788 }
 789
 790 XS(XS_Regexp_DESTROY)
 791 {
 792
 793 }
 794
 795 XS(XS_PerlIO_get_layers)
 796 {
 797     dXSARGS;
 798     if (items < 1 || items % 2 == 0)
 799         Perl_croak(aTHX_ "Usage: PerlIO_get_layers(filehandle[,args])");
 800 #ifdef USE_PERLIO
 801     {
 802         SV *    sv;
 803         GV *    gv;
 804         IO *    io;
 805         bool    input = TRUE;
 806         bool    details = FALSE;
 807
 808         if (items > 1) {
 809              SV **svp;
 810
 811              for (svp = MARK + 2; svp <= SP; svp += 2) {
 812                   SV **varp = svp;
 813                   SV **valp = svp + 1;
 814                   STRLEN klen;
 815                   char *key = SvPV(*varp, klen);
 816
 817                   switch (*key) {
 818                   case 'i':
 819                        if (klen == 5 && memEQ(key, "input", 5)) {
 820                             input = SvTRUE(*valp);
 821                             break;
 822                        }
 823                        goto fail;
 824                   case 'o':
 825                        if (klen == 6 && memEQ(key, "output", 6)) {
 826                             input = !SvTRUE(*valp);
 827                             break;
 828                        }
 829                        goto fail;
 830                   case 'd':
 831                        if (klen == 7 && memEQ(key, "details", 7)) {
 832                             details = SvTRUE(*valp);
 833                             break;
 834                        }
 835                        goto fail;
 836                   default:
 837                   fail:
 838                        Perl_croak(aTHX_
 839                                   "get_layers: unknown argument '%s'",
 840                                   key);
 841                   }
 842              }
 843
 844              SP -= (items - 1);
 845         }
 846
 847         sv = POPs;
 848         gv = (GV*)sv;
 849
 850         if (!isGV(sv)) {
 851              if (SvROK(sv) && isGV(SvRV(sv)))
 852                   gv = (GV*)SvRV(sv);
 853              else
 854                   gv = gv_fetchpv(SvPVX(sv), FALSE, SVt_PVIO);
 855         }
 856
 857         if (gv && (io = GvIO(gv))) {
 858              dTARGET;
 859              AV* av = PerlIO_get_layers(aTHX_ input ?
 860                                         IoIFP(io) : IoOFP(io));
 861              I32 i;
 862              I32 last = av_len(av);
 863              I32 nitem = 0;
 864
 865              for (i = last; i >= 0; i -= 3) {
 866                   SV **namsvp;
 867                   SV **argsvp;
 868                   SV **flgsvp;
 869                   bool namok, argok, flgok;
 870
 871                   namsvp = av_fetch(av, i - 2, FALSE);
 872                   argsvp = av_fetch(av, i - 1, FALSE);
 873                   flgsvp = av_fetch(av, i,     FALSE);
 874
 875                   namok = namsvp && *namsvp && SvPOK(*namsvp);
 876                   argok = argsvp && *argsvp && SvPOK(*argsvp);
 877                   flgok = flgsvp && *flgsvp && SvIOK(*flgsvp);
 878
 879                   if (details) {
 880                        XPUSHs(namok ?
 881                              newSVpv(SvPVX(*namsvp), 0) : &PL_sv_undef);
 882                        XPUSHs(argok ?
 883                              newSVpv(SvPVX(*argsvp), 0) : &PL_sv_undef);
 884                        if (flgok)
 885                             XPUSHi(SvIVX(*flgsvp));
 886                        else
 887                             XPUSHs(&PL_sv_undef);
 888                        nitem += 3;
 889                   }
 890                   else {
 891                        if (namok && argok)
 892                             XPUSHs(Perl_newSVpvf(aTHX_ "%"SVf"(%"SVf")",
 893                                                *namsvp, *argsvp));
 894                        else if (namok)
 895                             XPUSHs(Perl_newSVpvf(aTHX_ "%"SVf, *namsvp));
 896                        else
 897                             XPUSHs(&PL_sv_undef);
 898                        nitem++;
 899                        if (flgok) {
 900                             IV flags = SvIVX(*flgsvp);
 901
 902                             if (flags & PERLIO_F_UTF8) {
 903                                  XPUSHs(newSVpvn("utf8", 4));
 904                                  nitem++;
 905                             }
 906                        }
 907                   }
 908              }
 909
 910              SvREFCNT_dec(av);
 911
 912              XSRETURN(nitem);
 913         }
 914     }
 915 #endif
 916
 917     XSRETURN(0);
 918 }
 919
 920 XS(XS_Internals_hash_seed)
 921 {
 922     /* Using dXSARGS would also have dITEM and dSP,
 923      * which define 2 unused local variables.  */
 924     dMARK; dAX;
 925     XSRETURN_UV(PERL_HASH_SEED);
 926 }
 927
 928 XS(XS_Internals_rehash_seed)
 929 {
 930     /* Using dXSARGS would also have dITEM and dSP,
 931      * which define 2 unused local variables.  */
 932     dMARK; dAX;
 933     XSRETURN_UV(PL_rehash_seed);
 934 }
 935
 936 XS(XS_Internals_HvREHASH)       /* Subject to change  */
 937 {
 938     dXSARGS;
 939     if (SvROK(ST(0))) {
 940         HV *hv = (HV *) SvRV(ST(0));
 941         if (items == 1 && SvTYPE(hv) == SVt_PVHV) {
 942             if (HvREHASH(hv))
 943                 XSRETURN_YES;
 944             else
 945                 XSRETURN_NO;
 946         }
 947     }
 948     Perl_croak(aTHX_ "Internals::HvREHASH $hashref");
 949 }