universal.c

   1 /*    universal.c
   2  *
   3  *    Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   4  *    2005, 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 /* This file contains the code that implements the functions in Perl's
  18  * UNIVERSAL package, such as UNIVERSAL->can().
  19  */
  20
  21 #include "EXTERN.h"
  22 #define PERL_IN_UNIVERSAL_C
  23 #include "perl.h"
  24
  25 #ifdef USE_PERLIO
  26 #include "perliol.h" /* For the PERLIO_F_XXX */
  27 #endif
  28
  29 /*
  30  * Contributed by Graham Barr  <Graham.Barr@tiuk.ti.com>
  31  * The main guts of traverse_isa was actually copied from gv_fetchmeth
  32  */
  33
  34 STATIC SV *
  35 S_isa_lookup(pTHX_ HV *stash, const char *name, HV* name_stash,
  36              int len, int level)
  37 {
  38     AV* av;
  39     GV* gv;
  40     GV** gvp;
  41     HV* hv = Nullhv;
  42     SV* subgen = Nullsv;
  43     const char *hvname;
  44
  45     /* A stash/class can go by many names (ie. User == main::User), so
  46        we compare the stash itself just in case */
  47     if (name_stash && (stash == name_stash))
  48         return &PL_sv_yes;
  49
  50     hvname = HvNAME_get(stash);
  51
  52     if (strEQ(hvname, name))
  53         return &PL_sv_yes;
  54
  55     if (strEQ(name, "UNIVERSAL"))
  56         return &PL_sv_yes;
  57
  58     if (level > 100)
  59         Perl_croak(aTHX_ "Recursive inheritance detected in package '%s'",
  60                    hvname);
  61
  62     gvp = (GV**)hv_fetch(stash, "::ISA::CACHE::", 14, FALSE);
  63
  64     if (gvp && (gv = *gvp) != (GV*)&PL_sv_undef && (subgen = GvSV(gv))
  65         && (hv = GvHV(gv)))
  66     {
  67         if (SvIV(subgen) == (IV)PL_sub_generation) {
  68             SV* sv;
  69             SV** svp = (SV**)hv_fetch(hv, name, len, FALSE);
  70             if (svp && (sv = *svp) != (SV*)&PL_sv_undef) {
  71                 DEBUG_o( Perl_deb(aTHX_ "Using cached ISA %s for package %s\n",
  72                                   name, hvname) );
  73                 return sv;
  74             }
  75         }
  76         else {
  77             DEBUG_o( Perl_deb(aTHX_ "ISA Cache in package %s is stale\n",
  78                               hvname) );
  79             hv_clear(hv);
  80             sv_setiv(subgen, PL_sub_generation);
  81         }
  82     }
  83
  84     gvp = (GV**)hv_fetch(stash,"ISA",3,FALSE);
  85
  86     if (gvp && (gv = *gvp) != (GV*)&PL_sv_undef && (av = GvAV(gv))) {
  87         if (!hv || !subgen) {
  88             gvp = (GV**)hv_fetch(stash, "::ISA::CACHE::", 14, TRUE);
  89
  90             gv = *gvp;
  91
  92             if (SvTYPE(gv) != SVt_PVGV)
  93                 gv_init(gv, stash, "::ISA::CACHE::", 14, TRUE);
  94
  95             if (!hv)
  96                 hv = GvHVn(gv);
  97             if (!subgen) {
  98                 subgen = newSViv(PL_sub_generation);
  99                 GvSV(gv) = subgen;
 100             }
 101         }
 102         if (hv) {
 103             SV** svp = AvARRAY(av);
 104             /* NOTE: No support for tied ISA */
 105             I32 items = AvFILLp(av) + 1;
 106             while (items--) {
 107                 SV* sv = *svp++;
 108                 HV* basestash = gv_stashsv(sv, FALSE);
 109                 if (!basestash) {
 110                     if (ckWARN(WARN_MISC))
 111                         Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
 112                                     "Can't locate package %"SVf" for @%s::ISA",
 113                                     sv, hvname);
 114                     continue;
 115                 }
 116                 if (&PL_sv_yes == isa_lookup(basestash, name, name_stash,
 117                                              len, level + 1)) {
 118                     (void)hv_store(hv,name,len,&PL_sv_yes,0);
 119                     return &PL_sv_yes;
 120                 }
 121             }
 122             (void)hv_store(hv,name,len,&PL_sv_no,0);
 123         }
 124     }
 125     return &PL_sv_no;
 126 }
 127
 128 /*
 129 =head1 SV Manipulation Functions
 130
 131 =for apidoc sv_derived_from
 132
 133 Returns a boolean indicating whether the SV is derived from the specified
 134 class.  This is the function that implements C<UNIVERSAL::isa>.  It works
 135 for class names as well as for objects.
 136
 137 =cut
 138 */
 139
 140 bool
 141 Perl_sv_derived_from(pTHX_ SV *sv, const char *name)
 142 {
 143     const char *type = Nullch;
 144     HV *stash = Nullhv;
 145     HV *name_stash;
 146
 147     SvGETMAGIC(sv);
 148
 149     if (SvROK(sv)) {
 150         sv = SvRV(sv);
 151         type = sv_reftype(sv,0);
 152         if (SvOBJECT(sv))
 153             stash = SvSTASH(sv);
 154     }
 155     else {
 156         stash = gv_stashsv(sv, FALSE);
 157     }
 158
 159     name_stash = gv_stashpv(name, FALSE);
 160
 161     return (type && strEQ(type,name)) ||
 162             (stash && isa_lookup(stash, name, name_stash, strlen(name), 0)
 163              == &PL_sv_yes)
 164         ? TRUE
 165         : FALSE ;
 166 }
 167
 168 #include "XSUB.h"
 169
 170 PERL_XS_EXPORT_C void XS_UNIVERSAL_isa(pTHX_ CV *cv);
 171 PERL_XS_EXPORT_C void XS_UNIVERSAL_can(pTHX_ CV *cv);
 172 PERL_XS_EXPORT_C void XS_UNIVERSAL_VERSION(pTHX_ CV *cv);
 173 XS(XS_version_new);
 174 XS(XS_version_stringify);
 175 XS(XS_version_numify);
 176 XS(XS_version_normal);
 177 XS(XS_version_vcmp);
 178 XS(XS_version_boolean);
 179 #ifdef HASATTRIBUTE_NORETURN
 180 XS(XS_version_noop) __attribute__noreturn__;
 181 #else
 182 XS(XS_version_noop);
 183 #endif
 184 XS(XS_version_is_alpha);
 185 XS(XS_version_qv);
 186 XS(XS_utf8_is_utf8);
 187 XS(XS_utf8_valid);
 188 XS(XS_utf8_encode);
 189 XS(XS_utf8_decode);
 190 XS(XS_utf8_upgrade);
 191 XS(XS_utf8_downgrade);
 192 XS(XS_utf8_unicode_to_native);
 193 XS(XS_utf8_native_to_unicode);
 194 XS(XS_Internals_SvREADONLY);
 195 XS(XS_Internals_SvREFCNT);
 196 XS(XS_Internals_hv_clear_placehold);
 197 XS(XS_PerlIO_get_layers);
 198 XS(XS_Regexp_DESTROY);
 199 XS(XS_Internals_hash_seed);
 200 XS(XS_Internals_rehash_seed);
 201 XS(XS_Internals_HvREHASH);
 202
 203 void
 204 Perl_boot_core_UNIVERSAL(pTHX)
 205 {
 206     const char file[] = __FILE__;
 207
 208     newXS("UNIVERSAL::isa",             XS_UNIVERSAL_isa,         file);
 209     newXS("UNIVERSAL::can",             XS_UNIVERSAL_can,         file);
 210     newXS("UNIVERSAL::VERSION",         XS_UNIVERSAL_VERSION,     file);
 211     {
 212         /* register the overloading (type 'A') magic */
 213         PL_amagic_generation++;
 214         /* Make it findable via fetchmethod */
 215         newXS("version::()", XS_version_noop, file);
 216         newXS("version::new", XS_version_new, file);
 217         newXS("version::(\"\"", XS_version_stringify, file);
 218         newXS("version::stringify", XS_version_stringify, file);
 219         newXS("version::(0+", XS_version_numify, file);
 220         newXS("version::numify", XS_version_numify, file);
 221         newXS("version::normal", XS_version_normal, file);
 222         newXS("version::(cmp", XS_version_vcmp, file);
 223         newXS("version::(<=>", XS_version_vcmp, file);
 224         newXS("version::vcmp", XS_version_vcmp, file);
 225         newXS("version::(bool", XS_version_boolean, file);
 226         newXS("version::boolean", XS_version_boolean, file);
 227         newXS("version::(nomethod", XS_version_noop, file);
 228         newXS("version::noop", XS_version_noop, file);
 229         newXS("version::is_alpha", XS_version_is_alpha, file);
 230         newXS("version::qv", XS_version_qv, file);
 231     }
 232     newXS("utf8::is_utf8", XS_utf8_is_utf8, file);
 233     newXS("utf8::valid", XS_utf8_valid, file);
 234     newXS("utf8::encode", XS_utf8_encode, file);
 235     newXS("utf8::decode", XS_utf8_decode, file);
 236     newXS("utf8::upgrade", XS_utf8_upgrade, file);
 237     newXS("utf8::downgrade", XS_utf8_downgrade, file);
 238     newXS("utf8::native_to_unicode", XS_utf8_native_to_unicode, file);
 239     newXS("utf8::unicode_to_native", XS_utf8_unicode_to_native, file);
 240     newXSproto("Internals::SvREADONLY",XS_Internals_SvREADONLY, file, "\\[$%@];$");
 241     newXSproto("Internals::SvREFCNT",XS_Internals_SvREFCNT, file, "\\[$%@];$");
 242     newXSproto("Internals::hv_clear_placeholders",
 243                XS_Internals_hv_clear_placehold, file, "\\%");
 244     newXSproto("PerlIO::get_layers",
 245                XS_PerlIO_get_layers, file, "*;@");
 246     newXS("Regexp::DESTROY", XS_Regexp_DESTROY, file);
 247     newXSproto("Internals::hash_seed",XS_Internals_hash_seed, file, "");
 248     newXSproto("Internals::rehash_seed",XS_Internals_rehash_seed, file, "");
 249     newXSproto("Internals::HvREHASH", XS_Internals_HvREHASH, file, "\\%");
 250 }
 251
 252
 253 XS(XS_UNIVERSAL_isa)
 254 {
 255     dXSARGS;
 256     SV *sv;
 257     const char *name;
 258
 259     if (items != 2)
 260         Perl_croak(aTHX_ "Usage: UNIVERSAL::isa(reference, kind)");
 261
 262     sv = ST(0);
 263
 264     SvGETMAGIC(sv);
 265
 266     if (!SvOK(sv) || !(SvROK(sv) || (SvPOK(sv) && SvCUR(sv))
 267                 || (SvGMAGICAL(sv) && SvPOKp(sv) && SvCUR(sv))))
 268         XSRETURN_UNDEF;
 269
 270     name = SvPV_nolen_const(ST(1));
 271
 272     ST(0) = boolSV(sv_derived_from(sv, name));
 273     XSRETURN(1);
 274 }
 275
 276 XS(XS_UNIVERSAL_can)
 277 {
 278     dXSARGS;
 279     SV   *sv;
 280     const char *name;
 281     SV   *rv;
 282     HV   *pkg = NULL;
 283
 284     if (items != 2)
 285         Perl_croak(aTHX_ "Usage: UNIVERSAL::can(object-ref, method)");
 286
 287     sv = ST(0);
 288
 289     SvGETMAGIC(sv);
 290
 291     if (!SvOK(sv) || !(SvROK(sv) || (SvPOK(sv) && SvCUR(sv))
 292                 || (SvGMAGICAL(sv) && SvPOKp(sv) && SvCUR(sv))))
 293         XSRETURN_UNDEF;
 294
 295     name = SvPV_nolen_const(ST(1));
 296     rv = &PL_sv_undef;
 297
 298     if (SvROK(sv)) {
 299         sv = (SV*)SvRV(sv);
 300         if (SvOBJECT(sv))
 301             pkg = SvSTASH(sv);
 302     }
 303     else {
 304         pkg = gv_stashsv(sv, FALSE);
 305     }
 306
 307     if (pkg) {
 308         GV *gv = gv_fetchmethod_autoload(pkg, name, FALSE);
 309         if (gv && isGV(gv))
 310             rv = sv_2mortal(newRV((SV*)GvCV(gv)));
 311     }
 312
 313     ST(0) = rv;
 314     XSRETURN(1);
 315 }
 316
 317 XS(XS_UNIVERSAL_VERSION)
 318 {
 319     dXSARGS;
 320     HV *pkg;
 321     GV **gvp;
 322     GV *gv;
 323     SV *sv;
 324     const char *undef;
 325
 326     if (SvROK(ST(0))) {
 327         sv = (SV*)SvRV(ST(0));
 328         if (!SvOBJECT(sv))
 329             Perl_croak(aTHX_ "Cannot find version of an unblessed reference");
 330         pkg = SvSTASH(sv);
 331     }
 332     else {
 333         pkg = gv_stashsv(ST(0), FALSE);
 334     }
 335
 336     gvp = pkg ? (GV**)hv_fetch(pkg,"VERSION",7,FALSE) : Null(GV**);
 337
 338     if (gvp && isGV(gv = *gvp) && (sv = GvSV(gv)) && SvOK(sv)) {
 339         SV *nsv = sv_newmortal();
 340         sv_setsv(nsv, sv);
 341         sv = nsv;
 342         if ( !sv_derived_from(sv, "version"))
 343             upg_version(sv);
 344         undef = Nullch;
 345     }
 346     else {
 347         sv = (SV*)&PL_sv_undef;
 348         undef = "(undef)";
 349     }
 350
 351     if (items > 1) {
 352         SV *req = ST(1);
 353
 354         if (undef) {
 355             if (pkg) {
 356                 const char *name = HvNAME_get(pkg);
 357                 Perl_croak(aTHX_
 358                            "%s does not define $%s::VERSION--version check failed",
 359                            name, name);
 360             } else {
 361                 Perl_croak(aTHX_
 362                              "%s defines neither package nor VERSION--version check failed",
 363                              SvPVx_nolen_const(ST(0)) );
 364              }
 365         }
 366
 367         if ( !sv_derived_from(req, "version")) {
 368             /* req may very well be R/O, so create a new object */
 369             SV *nsv = sv_newmortal();
 370             sv_setsv(nsv, req);
 371             req = nsv;
 372             upg_version(req);
 373         }
 374
 375         if ( vcmp( req, sv ) > 0 )
 376             Perl_croak(aTHX_ "%s version %"SVf" (%"SVf") required--"
 377                     "this is only version %"SVf" (%"SVf")", HvNAME_get(pkg),
 378                     vnumify(req),vnormal(req),vnumify(sv),vnormal(sv));
 379     }
 380
 381     if ( SvOK(sv) && sv_derived_from(sv, "version") ) {
 382         ST(0) = vnumify(sv);
 383     } else {
 384         ST(0) = sv;
 385     }
 386
 387     XSRETURN(1);
 388 }
 389
 390 XS(XS_version_new)
 391 {
 392     dXSARGS;
 393     if (items > 3)
 394         Perl_croak(aTHX_ "Usage: version::new(class, version)");
 395     SP -= items;
 396     {
 397         SV *vs = ST(1);
 398         SV *rv;
 399         const char *classname;
 400
 401         /* get the class if called as an object method */
 402         if ( sv_isobject(ST(0)) ) {
 403             classname = HvNAME(SvSTASH(SvRV(ST(0))));
 404         }
 405         else {
 406             classname = (char *)SvPV_nolen(ST(0));
 407         }
 408
 409         if ( items == 1 ) {
 410             /* no parameter provided */
 411             if ( sv_isobject(ST(0)) ) {
 412                 /* copy existing object */
 413                 vs = ST(0);
 414             }
 415             else {
 416                 /* create empty object */
 417                 vs = sv_newmortal();
 418                 sv_setpvn(vs,"",0);
 419             }
 420         }
 421         else if ( items == 3 ) {
 422             vs = sv_newmortal();
 423             Perl_sv_setpvf(aTHX_ vs,"v%s",SvPV_nolen_const(ST(2)));
 424         }
 425
 426         rv = new_version(vs);
 427         if ( strcmp(classname,"version") != 0 ) /* inherited new() */
 428             sv_bless(rv, gv_stashpv(classname,TRUE));
 429
 430         PUSHs(sv_2mortal(rv));
 431         PUTBACK;
 432         return;
 433     }
 434 }
 435
 436 XS(XS_version_stringify)
 437 {
 438      dXSARGS;
 439      if (items < 1)
 440           Perl_croak(aTHX_ "Usage: version::stringify(lobj, ...)");
 441      SP -= items;
 442      {
 443           SV *  lobj = Nullsv;
 444
 445           if (sv_derived_from(ST(0), "version")) {
 446                lobj = SvRV(ST(0));
 447           }
 448           else
 449                Perl_croak(aTHX_ "lobj is not of type version");
 450
 451           PUSHs(sv_2mortal(vstringify(lobj)));
 452
 453           PUTBACK;
 454           return;
 455      }
 456 }
 457
 458 XS(XS_version_numify)
 459 {
 460      dXSARGS;
 461      if (items < 1)
 462           Perl_croak(aTHX_ "Usage: version::numify(lobj, ...)");
 463      SP -= items;
 464      {
 465           SV *  lobj = Nullsv;
 466
 467           if (sv_derived_from(ST(0), "version")) {
 468                lobj = SvRV(ST(0));
 469           }
 470           else
 471                Perl_croak(aTHX_ "lobj is not of type version");
 472
 473           PUSHs(sv_2mortal(vnumify(lobj)));
 474
 475           PUTBACK;
 476           return;
 477      }
 478 }
 479
 480 XS(XS_version_normal)
 481 {
 482      dXSARGS;
 483      if (items < 1)
 484           Perl_croak(aTHX_ "Usage: version::normal(lobj, ...)");
 485      SP -= items;
 486      {
 487           SV *  lobj = Nullsv;
 488
 489           if (sv_derived_from(ST(0), "version")) {
 490                lobj = SvRV(ST(0));
 491           }
 492           else
 493                Perl_croak(aTHX_ "lobj is not of type version");
 494
 495           PUSHs(sv_2mortal(vnormal(lobj)));
 496
 497           PUTBACK;
 498           return;
 499      }
 500 }
 501
 502 XS(XS_version_vcmp)
 503 {
 504      dXSARGS;
 505      if (items < 1)
 506           Perl_croak(aTHX_ "Usage: version::vcmp(lobj, ...)");
 507      SP -= items;
 508      {
 509           SV *  lobj = Nullsv;
 510
 511           if (sv_derived_from(ST(0), "version")) {
 512                lobj = SvRV(ST(0));
 513           }
 514           else
 515                Perl_croak(aTHX_ "lobj is not of type version");
 516
 517           {
 518                SV       *rs;
 519                SV       *rvs;
 520                SV * robj = ST(1);
 521                IV        swap = (IV)SvIV(ST(2));
 522
 523                if ( ! sv_derived_from(robj, "version") )
 524                {
 525                     robj = new_version(robj);
 526                }
 527                rvs = SvRV(robj);
 528
 529                if ( swap )
 530                {
 531                     rs = newSViv(vcmp(rvs,lobj));
 532                }
 533                else
 534                {
 535                     rs = newSViv(vcmp(lobj,rvs));
 536                }
 537
 538                PUSHs(sv_2mortal(rs));
 539           }
 540
 541           PUTBACK;
 542           return;
 543      }
 544 }
 545
 546 XS(XS_version_boolean)
 547 {
 548      dXSARGS;
 549      if (items < 1)
 550           Perl_croak(aTHX_ "Usage: version::boolean(lobj, ...)");
 551      SP -= items;
 552      {
 553           SV *  lobj = Nullsv;
 554
 555           if (sv_derived_from(ST(0), "version")) {
 556                lobj = SvRV(ST(0));
 557           }
 558           else
 559                Perl_croak(aTHX_ "lobj is not of type version");
 560
 561           {
 562                SV       *rs;
 563                rs = newSViv( vcmp(lobj,new_version(newSVpvn("0",1))) );
 564                PUSHs(sv_2mortal(rs));
 565           }
 566
 567           PUTBACK;
 568           return;
 569      }
 570 }
 571
 572 XS(XS_version_noop)
 573 {
 574     dXSARGS;
 575     if (items < 1)
 576         Perl_croak(aTHX_ "Usage: version::noop(lobj, ...)");
 577     if (sv_derived_from(ST(0), "version"))
 578         Perl_croak(aTHX_ "operation not supported with version object");
 579     else
 580         Perl_croak(aTHX_ "lobj is not of type version");
 581 #ifndef HASATTRIBUTE_NORETURN
 582     XSRETURN_EMPTY;
 583 #endif
 584 }
 585
 586 XS(XS_version_is_alpha)
 587 {
 588     dXSARGS;
 589     if (items != 1)
 590         Perl_croak(aTHX_ "Usage: version::is_alpha(lobj)");
 591     SP -= items;
 592     {
 593         SV * lobj = Nullsv;
 594
 595         if (sv_derived_from(ST(0), "version"))
 596                 lobj = ST(0);
 597         else
 598                 Perl_croak(aTHX_ "lobj is not of type version");
 599 {
 600     if ( hv_exists((HV*)SvRV(lobj), "alpha", 5 ) )
 601         XSRETURN_YES;
 602     else
 603         XSRETURN_NO;
 604 }
 605         PUTBACK;
 606         return;
 607     }
 608 }
 609
 610 XS(XS_version_qv)
 611 {
 612     dXSARGS;
 613     if (items != 1)
 614         Perl_croak(aTHX_ "Usage: version::qv(ver)");
 615     SP -= items;
 616     {
 617         SV *    ver = ST(0);
 618         if ( !SvVOK(ver) ) /* only need to do with if not already v-string */
 619         {
 620             SV *vs = sv_newmortal();
 621             char *version;
 622             if ( SvNOK(ver) ) /* may get too much accuracy */
 623             {
 624                 char tbuf[64];
 625                 sprintf(tbuf,"%.9"NVgf, SvNVX(ver));
 626                 version = savepv(tbuf);
 627             }
 628             else
 629             {
 630                 version = savesvpv(ver);
 631             }
 632             (void)scan_version(version,vs,TRUE);
 633             Safefree(version);
 634
 635             PUSHs(vs);
 636         }
 637         else
 638         {
 639             PUSHs(sv_2mortal(new_version(ver)));
 640         }
 641
 642         PUTBACK;
 643         return;
 644     }
 645 }
 646
 647 XS(XS_utf8_is_utf8)
 648 {
 649      dXSARGS;
 650      if (items != 1)
 651           Perl_croak(aTHX_ "Usage: utf8::is_utf8(sv)");
 652      {
 653           const SV *sv = ST(0);
 654           {
 655                if (SvUTF8(sv))
 656                     XSRETURN_YES;
 657                else
 658                     XSRETURN_NO;
 659           }
 660      }
 661      XSRETURN_EMPTY;
 662 }
 663
 664 XS(XS_utf8_valid)
 665 {
 666      dXSARGS;
 667      if (items != 1)
 668           Perl_croak(aTHX_ "Usage: utf8::valid(sv)");
 669      {
 670           SV *  sv = ST(0);
 671           {
 672                STRLEN len;
 673                const char *s = SvPV_const(sv,len);
 674                if (!SvUTF8(sv) || is_utf8_string((const U8*)s,len))
 675                     XSRETURN_YES;
 676                else
 677                     XSRETURN_NO;
 678           }
 679      }
 680      XSRETURN_EMPTY;
 681 }
 682
 683 XS(XS_utf8_encode)
 684 {
 685     dXSARGS;
 686     if (items != 1)
 687         Perl_croak(aTHX_ "Usage: utf8::encode(sv)");
 688     {
 689         SV *    sv = ST(0);
 690
 691         sv_utf8_encode(sv);
 692     }
 693     XSRETURN_EMPTY;
 694 }
 695
 696 XS(XS_utf8_decode)
 697 {
 698     dXSARGS;
 699     if (items != 1)
 700         Perl_croak(aTHX_ "Usage: utf8::decode(sv)");
 701     {
 702         SV *    sv = ST(0);
 703         const bool RETVAL = sv_utf8_decode(sv);
 704         ST(0) = boolSV(RETVAL);
 705         sv_2mortal(ST(0));
 706     }
 707     XSRETURN(1);
 708 }
 709
 710 XS(XS_utf8_upgrade)
 711 {
 712     dXSARGS;
 713     if (items != 1)
 714         Perl_croak(aTHX_ "Usage: utf8::upgrade(sv)");
 715     {
 716         SV *    sv = ST(0);
 717         STRLEN  RETVAL;
 718         dXSTARG;
 719
 720         RETVAL = sv_utf8_upgrade(sv);
 721         XSprePUSH; PUSHi((IV)RETVAL);
 722     }
 723     XSRETURN(1);
 724 }
 725
 726 XS(XS_utf8_downgrade)
 727 {
 728     dXSARGS;
 729     if (items < 1 || items > 2)
 730         Perl_croak(aTHX_ "Usage: utf8::downgrade(sv, failok=0)");
 731     {
 732         SV *    sv = ST(0);
 733         const bool failok = (items < 2) ? 0 : (int)SvIV(ST(1));
 734         const bool RETVAL = sv_utf8_downgrade(sv, failok);
 735
 736         ST(0) = boolSV(RETVAL);
 737         sv_2mortal(ST(0));
 738     }
 739     XSRETURN(1);
 740 }
 741
 742 XS(XS_utf8_native_to_unicode)
 743 {
 744  dXSARGS;
 745  const UV uv = SvUV(ST(0));
 746
 747  if (items > 1)
 748      Perl_croak(aTHX_ "Usage: utf8::native_to_unicode(sv)");
 749
 750  ST(0) = sv_2mortal(newSViv(NATIVE_TO_UNI(uv)));
 751  XSRETURN(1);
 752 }
 753
 754 XS(XS_utf8_unicode_to_native)
 755 {
 756  dXSARGS;
 757  const UV uv = SvUV(ST(0));
 758
 759  if (items > 1)
 760      Perl_croak(aTHX_ "Usage: utf8::unicode_to_native(sv)");
 761
 762  ST(0) = sv_2mortal(newSViv(UNI_TO_NATIVE(uv)));
 763  XSRETURN(1);
 764 }
 765
 766 XS(XS_Internals_SvREADONLY)     /* This is dangerous stuff. */
 767 {
 768     dXSARGS;
 769     SV *sv = SvRV(ST(0));
 770
 771     if (items == 1) {
 772          if (SvREADONLY(sv))
 773              XSRETURN_YES;
 774          else
 775              XSRETURN_NO;
 776     }
 777     else if (items == 2) {
 778         if (SvTRUE(ST(1))) {
 779             SvREADONLY_on(sv);
 780             XSRETURN_YES;
 781         }
 782         else {
 783             /* I hope you really know what you are doing. */
 784             SvREADONLY_off(sv);
 785             XSRETURN_NO;
 786         }
 787     }
 788     XSRETURN_UNDEF; /* Can't happen. */
 789 }
 790
 791 XS(XS_Internals_SvREFCNT)       /* This is dangerous stuff. */
 792 {
 793     dXSARGS;
 794     SV *sv = SvRV(ST(0));
 795
 796     if (items == 1)
 797          XSRETURN_IV(SvREFCNT(sv) - 1); /* Minus the ref created for us. */
 798     else if (items == 2) {
 799          /* I hope you really know what you are doing. */
 800          SvREFCNT(sv) = SvIV(ST(1));
 801          XSRETURN_IV(SvREFCNT(sv));
 802     }
 803     XSRETURN_UNDEF; /* Can't happen. */
 804 }
 805
 806 XS(XS_Internals_hv_clear_placehold)
 807 {
 808     dXSARGS;
 809     HV *hv = (HV *) SvRV(ST(0));
 810
 811     if (items != 1)
 812         Perl_croak(aTHX_ "Usage: UNIVERSAL::hv_clear_placeholders(hv)");
 813     hv_clear_placeholders(hv);
 814     XSRETURN(0);
 815 }
 816
 817 XS(XS_Regexp_DESTROY)
 818 {
 819     PERL_UNUSED_ARG(cv);
 820 }
 821
 822 XS(XS_PerlIO_get_layers)
 823 {
 824     dXSARGS;
 825     if (items < 1 || items % 2 == 0)
 826         Perl_croak(aTHX_ "Usage: PerlIO_get_layers(filehandle[,args])");
 827 #ifdef USE_PERLIO
 828     {
 829         SV *    sv;
 830         GV *    gv;
 831         IO *    io;
 832         bool    input = TRUE;
 833         bool    details = FALSE;
 834
 835         if (items > 1) {
 836              SV **svp;
 837
 838              for (svp = MARK + 2; svp <= SP; svp += 2) {
 839                   SV **varp = svp;
 840                   SV **valp = svp + 1;
 841                   STRLEN klen;
 842                   const char *key = SvPV_const(*varp, klen);
 843
 844                   switch (*key) {
 845                   case 'i':
 846                        if (klen == 5 && memEQ(key, "input", 5)) {
 847                             input = SvTRUE(*valp);
 848                             break;
 849                        }
 850                        goto fail;
 851                   case 'o':
 852                        if (klen == 6 && memEQ(key, "output", 6)) {
 853                             input = !SvTRUE(*valp);
 854                             break;
 855                        }
 856                        goto fail;
 857                   case 'd':
 858                        if (klen == 7 && memEQ(key, "details", 7)) {
 859                             details = SvTRUE(*valp);
 860                             break;
 861                        }
 862                        goto fail;
 863                   default:
 864                   fail:
 865                        Perl_croak(aTHX_
 866                                   "get_layers: unknown argument '%s'",
 867                                   key);
 868                   }
 869              }
 870
 871              SP -= (items - 1);
 872         }
 873
 874         sv = POPs;
 875         gv = (GV*)sv;
 876
 877         if (!isGV(sv)) {
 878              if (SvROK(sv) && isGV(SvRV(sv)))
 879                   gv = (GV*)SvRV(sv);
 880              else
 881                   gv = gv_fetchsv(sv, FALSE, SVt_PVIO);
 882         }
 883
 884         if (gv && (io = GvIO(gv))) {
 885              dTARGET;
 886              AV* av = PerlIO_get_layers(aTHX_ input ?
 887                                         IoIFP(io) : IoOFP(io));
 888              I32 i;
 889              I32 last = av_len(av);
 890              I32 nitem = 0;
 891
 892              for (i = last; i >= 0; i -= 3) {
 893                   SV **namsvp;
 894                   SV **argsvp;
 895                   SV **flgsvp;
 896                   bool namok, argok, flgok;
 897
 898                   namsvp = av_fetch(av, i - 2, FALSE);
 899                   argsvp = av_fetch(av, i - 1, FALSE);
 900                   flgsvp = av_fetch(av, i,     FALSE);
 901
 902                   namok = namsvp && *namsvp && SvPOK(*namsvp);
 903                   argok = argsvp && *argsvp && SvPOK(*argsvp);
 904                   flgok = flgsvp && *flgsvp && SvIOK(*flgsvp);
 905
 906                   if (details) {
 907                        XPUSHs(namok
 908                               ? newSVpvn(SvPVX_const(*namsvp), SvCUR(*namsvp))
 909                               : &PL_sv_undef);
 910                        XPUSHs(argok
 911                               ? newSVpvn(SvPVX_const(*argsvp), SvCUR(*argsvp))
 912                               : &PL_sv_undef);
 913                        if (flgok)
 914                             XPUSHi(SvIVX(*flgsvp));
 915                        else
 916                             XPUSHs(&PL_sv_undef);
 917                        nitem += 3;
 918                   }
 919                   else {
 920                        if (namok && argok)
 921                             XPUSHs(Perl_newSVpvf(aTHX_ "%"SVf"(%"SVf")",
 922                                                *namsvp, *argsvp));
 923                        else if (namok)
 924                             XPUSHs(Perl_newSVpvf(aTHX_ "%"SVf, *namsvp));
 925                        else
 926                             XPUSHs(&PL_sv_undef);
 927                        nitem++;
 928                        if (flgok) {
 929                             IV flags = SvIVX(*flgsvp);
 930
 931                             if (flags & PERLIO_F_UTF8) {
 932                                  XPUSHs(newSVpvn("utf8", 4));
 933                                  nitem++;
 934                             }
 935                        }
 936                   }
 937              }
 938
 939              SvREFCNT_dec(av);
 940
 941              XSRETURN(nitem);
 942         }
 943     }
 944 #endif
 945
 946     XSRETURN(0);
 947 }
 948
 949 XS(XS_Internals_hash_seed)
 950 {
 951     /* Using dXSARGS would also have dITEM and dSP,
 952      * which define 2 unused local variables.  */
 953     dAXMARK;
 954     PERL_UNUSED_ARG(cv);
 955     PERL_UNUSED_VAR(mark);
 956     XSRETURN_UV(PERL_HASH_SEED);
 957 }
 958
 959 XS(XS_Internals_rehash_seed)
 960 {
 961     /* Using dXSARGS would also have dITEM and dSP,
 962      * which define 2 unused local variables.  */
 963     dAXMARK;
 964     PERL_UNUSED_ARG(cv);
 965     PERL_UNUSED_VAR(mark);
 966     XSRETURN_UV(PL_rehash_seed);
 967 }
 968
 969 XS(XS_Internals_HvREHASH)       /* Subject to change  */
 970 {
 971     dXSARGS;
 972     if (SvROK(ST(0))) {
 973         const HV *hv = (HV *) SvRV(ST(0));
 974         if (items == 1 && SvTYPE(hv) == SVt_PVHV) {
 975             if (HvREHASH(hv))
 976                 XSRETURN_YES;
 977             else
 978                 XSRETURN_NO;
 979         }
 980     }
 981     Perl_croak(aTHX_ "Internals::HvREHASH $hashref");
 982 }
 983
 984 /*
 985  * Local variables:
 986  * c-indentation-style: bsd
 987  * c-basic-offset: 4
 988  * indent-tabs-mode: t
 989  * End:
 990  *
 991  * ex: set ts=8 sts=4 sw=4 noet:
 992  */