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