universal.c

   1 /*    universal.c
   2  *
   3  *    Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   4  *    2005, 2006, 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 bool
  35 S_isa_lookup(pTHX_ HV *stash, const char *name, HV* name_stash,
  36              int len, int level)
  37 {
  38     dVAR;
  39     AV* av;
  40     GV* gv;
  41     GV** gvp;
  42     HV* hv = NULL;
  43     SV* subgen = NULL;
  44     const char *hvname;
  45
  46     /* A stash/class can go by many names (ie. User == main::User), so
  47        we compare the stash itself just in case */
  48     if (name_stash && (stash == name_stash))
  49         return TRUE;
  50
  51     hvname = HvNAME_get(stash);
  52
  53     if (strEQ(hvname, name))
  54         return TRUE;
  55
  56     if (strEQ(name, "UNIVERSAL"))
  57         return TRUE;
  58
  59     if (level > 100)
  60         Perl_croak(aTHX_ "Recursive inheritance detected in package '%s'",
  61                    hvname);
  62
  63     gvp = (GV**)hv_fetchs(stash, "::ISA::CACHE::", FALSE);
  64
  65     if (gvp && (gv = *gvp) != (GV*)&PL_sv_undef && (subgen = GvSV(gv))
  66         && (hv = GvHV(gv)))
  67     {
  68         if (SvIV(subgen) == (IV)PL_sub_generation) {
  69             SV* sv;
  70             SV** const svp = (SV**)hv_fetch(hv, name, len, FALSE);
  71             if (svp && (sv = *svp) != (SV*)&PL_sv_undef) {
  72                 DEBUG_o( Perl_deb(aTHX_ "Using cached ISA %s for package %s\n",
  73                                   name, hvname) );
  74                 return (sv == &PL_sv_yes);
  75             }
  76         }
  77         else {
  78             DEBUG_o( Perl_deb(aTHX_ "ISA Cache in package %s is stale\n",
  79                               hvname) );
  80             hv_clear(hv);
  81             sv_setiv(subgen, PL_sub_generation);
  82         }
  83     }
  84
  85     gvp = (GV**)hv_fetchs(stash, "ISA", FALSE);
  86
  87     if (gvp && (gv = *gvp) != (GV*)&PL_sv_undef && (av = GvAV(gv))) {
  88         if (!hv || !subgen) {
  89             gvp = (GV**)hv_fetchs(stash, "::ISA::CACHE::", TRUE);
  90
  91             gv = *gvp;
  92
  93             if (SvTYPE(gv) != SVt_PVGV)
  94                 gv_init(gv, stash, "::ISA::CACHE::", 14, TRUE);
  95
  96             if (!hv)
  97                 hv = GvHVn(gv);
  98             if (!subgen) {
  99                 subgen = newSViv(PL_sub_generation);
 100                 GvSV(gv) = subgen;
 101             }
 102         }
 103         if (hv) {
 104             SV** svp = AvARRAY(av);
 105             /* NOTE: No support for tied ISA */
 106             I32 items = AvFILLp(av) + 1;
 107             while (items--) {
 108                 SV* const sv = *svp++;
 109                 HV* const basestash = gv_stashsv(sv, FALSE);
 110                 if (!basestash) {
 111                     if (ckWARN(WARN_MISC))
 112                         Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
 113                                     "Can't locate package %"SVf" for @%s::ISA",
 114                                     (void*)sv, hvname);
 115                     continue;
 116                 }
 117                 if (isa_lookup(basestash, name, name_stash, len, level + 1)) {
 118                     (void)hv_store(hv,name,len,&PL_sv_yes,0);
 119                     return TRUE;
 120                 }
 121             }
 122             (void)hv_store(hv,name,len,&PL_sv_no,0);
 123         }
 124     }
 125     return FALSE;
 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 class
 134 I<at the C level>.  To check derivation at the Perl level, call C<isa()> as a
 135 normal Perl method.
 136
 137 =cut
 138 */
 139
 140 bool
 141 Perl_sv_derived_from(pTHX_ SV *sv, const char *name)
 142 {
 143     dVAR;
 144     HV *stash;
 145
 146     SvGETMAGIC(sv);
 147
 148     if (SvROK(sv)) {
 149         const char *type;
 150         sv = SvRV(sv);
 151         type = sv_reftype(sv,0);
 152         if (type && strEQ(type,name))
 153             return TRUE;
 154         stash = SvOBJECT(sv) ? SvSTASH(sv) : NULL;
 155     }
 156     else {
 157         stash = gv_stashsv(sv, FALSE);
 158     }
 159
 160     if (stash) {
 161         HV * const name_stash = gv_stashpv(name, FALSE);
 162         return isa_lookup(stash, name, name_stash, strlen(name), 0);
 163     }
 164     else
 165         return FALSE;
 166
 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 XS(XS_Internals_inc_sub_generation);
 204
 205 void
 206 Perl_boot_core_UNIVERSAL(pTHX)
 207 {
 208     dVAR;
 209     static const char file[] = __FILE__;
 210
 211     newXS("UNIVERSAL::isa",             XS_UNIVERSAL_isa,         file);
 212     newXS("UNIVERSAL::can",             XS_UNIVERSAL_can,         file);
 213     newXS("UNIVERSAL::VERSION",         XS_UNIVERSAL_VERSION,     file);
 214     {
 215         /* register the overloading (type 'A') magic */
 216         PL_amagic_generation++;
 217         /* Make it findable via fetchmethod */
 218         newXS("version::()", XS_version_noop, file);
 219         newXS("version::new", XS_version_new, file);
 220         newXS("version::(\"\"", XS_version_stringify, file);
 221         newXS("version::stringify", XS_version_stringify, file);
 222         newXS("version::(0+", XS_version_numify, file);
 223         newXS("version::numify", XS_version_numify, file);
 224         newXS("version::normal", XS_version_normal, file);
 225         newXS("version::(cmp", XS_version_vcmp, file);
 226         newXS("version::(<=>", XS_version_vcmp, file);
 227         newXS("version::vcmp", XS_version_vcmp, file);
 228         newXS("version::(bool", XS_version_boolean, file);
 229         newXS("version::boolean", XS_version_boolean, file);
 230         newXS("version::(nomethod", XS_version_noop, file);
 231         newXS("version::noop", XS_version_noop, file);
 232         newXS("version::is_alpha", XS_version_is_alpha, file);
 233         newXS("version::qv", XS_version_qv, file);
 234     }
 235     newXS("utf8::is_utf8", XS_utf8_is_utf8, file);
 236     newXS("utf8::valid", XS_utf8_valid, file);
 237     newXS("utf8::encode", XS_utf8_encode, file);
 238     newXS("utf8::decode", XS_utf8_decode, file);
 239     newXS("utf8::upgrade", XS_utf8_upgrade, file);
 240     newXS("utf8::downgrade", XS_utf8_downgrade, file);
 241     newXS("utf8::native_to_unicode", XS_utf8_native_to_unicode, file);
 242     newXS("utf8::unicode_to_native", XS_utf8_unicode_to_native, file);
 243     newXSproto("Internals::SvREADONLY",XS_Internals_SvREADONLY, file, "\\[$%@];$");
 244     newXSproto("Internals::SvREFCNT",XS_Internals_SvREFCNT, file, "\\[$%@];$");
 245     newXSproto("Internals::hv_clear_placeholders",
 246                XS_Internals_hv_clear_placehold, file, "\\%");
 247     newXSproto("PerlIO::get_layers",
 248                XS_PerlIO_get_layers, file, "*;@");
 249     newXS("Regexp::DESTROY", XS_Regexp_DESTROY, file);
 250     newXSproto("Internals::hash_seed",XS_Internals_hash_seed, file, "");
 251     newXSproto("Internals::rehash_seed",XS_Internals_rehash_seed, file, "");
 252     newXSproto("Internals::HvREHASH", XS_Internals_HvREHASH, file, "\\%");
 253     newXSproto("Internals::inc_sub_generation",XS_Internals_inc_sub_generation,
 254                file, "");
 255 }
 256
 257
 258 XS(XS_UNIVERSAL_isa)
 259 {
 260     dVAR;
 261     dXSARGS;
 262
 263     if (items != 2)
 264         Perl_croak(aTHX_ "Usage: UNIVERSAL::isa(reference, kind)");
 265     else {
 266         SV * const sv = ST(0);
 267         const char *name;
 268
 269         SvGETMAGIC(sv);
 270
 271         if (!SvOK(sv) || !(SvROK(sv) || (SvPOK(sv) && SvCUR(sv))
 272                     || (SvGMAGICAL(sv) && SvPOKp(sv) && SvCUR(sv))))
 273             XSRETURN_UNDEF;
 274
 275         name = SvPV_nolen_const(ST(1));
 276
 277         ST(0) = boolSV(sv_derived_from(sv, name));
 278         XSRETURN(1);
 279     }
 280 }
 281
 282 XS(XS_UNIVERSAL_can)
 283 {
 284     dVAR;
 285     dXSARGS;
 286     SV   *sv;
 287     const char *name;
 288     SV   *rv;
 289     HV   *pkg = NULL;
 290
 291     if (items != 2)
 292         Perl_croak(aTHX_ "Usage: UNIVERSAL::can(object-ref, method)");
 293
 294     sv = ST(0);
 295
 296     SvGETMAGIC(sv);
 297
 298     if (!SvOK(sv) || !(SvROK(sv) || (SvPOK(sv) && SvCUR(sv))
 299                 || (SvGMAGICAL(sv) && SvPOKp(sv) && SvCUR(sv))))
 300         XSRETURN_UNDEF;
 301
 302     name = SvPV_nolen_const(ST(1));
 303     rv = &PL_sv_undef;
 304
 305     if (SvROK(sv)) {
 306         sv = (SV*)SvRV(sv);
 307         if (SvOBJECT(sv))
 308             pkg = SvSTASH(sv);
 309     }
 310     else {
 311         pkg = gv_stashsv(sv, FALSE);
 312     }
 313
 314     if (pkg) {
 315         GV * const gv = gv_fetchmethod_autoload(pkg, name, FALSE);
 316         if (gv && isGV(gv))
 317             rv = sv_2mortal(newRV((SV*)GvCV(gv)));
 318     }
 319
 320     ST(0) = rv;
 321     XSRETURN(1);
 322 }
 323
 324 XS(XS_UNIVERSAL_VERSION)
 325 {
 326     dVAR;
 327     dXSARGS;
 328     HV *pkg;
 329     GV **gvp;
 330     GV *gv;
 331     SV *sv;
 332     const char *undef;
 333
 334     if (SvROK(ST(0))) {
 335         sv = (SV*)SvRV(ST(0));
 336         if (!SvOBJECT(sv))
 337             Perl_croak(aTHX_ "Cannot find version of an unblessed reference");
 338         pkg = SvSTASH(sv);
 339     }
 340     else {
 341         pkg = gv_stashsv(ST(0), FALSE);
 342     }
 343
 344     gvp = pkg ? (GV**)hv_fetchs(pkg, "VERSION", FALSE) : NULL;
 345
 346     if (gvp && isGV(gv = *gvp) && (sv = GvSV(gv)) && SvOK(sv)) {
 347         SV * const nsv = sv_newmortal();
 348         sv_setsv(nsv, sv);
 349         sv = nsv;
 350         if ( !sv_derived_from(sv, "version"))
 351             upg_version(sv);
 352         undef = NULL;
 353     }
 354     else {
 355         sv = (SV*)&PL_sv_undef;
 356         undef = "(undef)";
 357     }
 358
 359     if (items > 1) {
 360         SV *req = ST(1);
 361
 362         if (undef) {
 363             if (pkg) {
 364                 const char * const name = HvNAME_get(pkg);
 365                 Perl_croak(aTHX_
 366                            "%s does not define $%s::VERSION--version check failed",
 367                            name, name);
 368             } else {
 369                 Perl_croak(aTHX_
 370                              "%s defines neither package nor VERSION--version check failed",
 371                              SvPVx_nolen_const(ST(0)) );
 372              }
 373         }
 374
 375         if ( !sv_derived_from(req, "version")) {
 376             /* req may very well be R/O, so create a new object */
 377             SV * const nsv = sv_newmortal();
 378             sv_setsv(nsv, req);
 379             req = nsv;
 380             upg_version(req);
 381         }
 382
 383         if ( vcmp( req, sv ) > 0 )
 384             Perl_croak(aTHX_ "%s version %"SVf" (%"SVf") required--"
 385                        "this is only version %"SVf" (%"SVf")", HvNAME_get(pkg),
 386                        (void*)vnumify(req),
 387                        (void*)vnormal(req),
 388                        (void*)vnumify(sv),
 389                        (void*)vnormal(sv));
 390     }
 391
 392     if ( SvOK(sv) && sv_derived_from(sv, "version") ) {
 393         ST(0) = vnumify(sv);
 394     } else {
 395         ST(0) = sv;
 396     }
 397
 398     XSRETURN(1);
 399 }
 400
 401 XS(XS_version_new)
 402 {
 403     dVAR;
 404     dXSARGS;
 405     if (items > 3)
 406         Perl_croak(aTHX_ "Usage: version::new(class, version)");
 407     SP -= items;
 408     {
 409         SV *vs = ST(1);
 410         SV *rv;
 411         const char * const classname =
 412             sv_isobject(ST(0)) /* get the class if called as an object method */
 413                 ? HvNAME(SvSTASH(SvRV(ST(0))))
 414                 : (char *)SvPV_nolen(ST(0));
 415
 416         if ( items == 1 ) {
 417             /* no parameter provided */
 418             if ( sv_isobject(ST(0)) ) {
 419                 /* copy existing object */
 420                 vs = ST(0);
 421             }
 422             else {
 423                 /* create empty object */
 424                 vs = sv_newmortal();
 425                 sv_setpvn(vs,"",0);
 426             }
 427         }
 428         else if ( items == 3 ) {
 429             vs = sv_newmortal();
 430             Perl_sv_setpvf(aTHX_ vs,"v%s",SvPV_nolen_const(ST(2)));
 431         }
 432
 433         rv = new_version(vs);
 434         if ( strcmp(classname,"version") != 0 ) /* inherited new() */
 435             sv_bless(rv, gv_stashpv(classname,TRUE));
 436
 437         PUSHs(sv_2mortal(rv));
 438         PUTBACK;
 439         return;
 440     }
 441 }
 442
 443 XS(XS_version_stringify)
 444 {
 445      dVAR;
 446      dXSARGS;
 447      if (items < 1)
 448           Perl_croak(aTHX_ "Usage: version::stringify(lobj, ...)");
 449      SP -= items;
 450      {
 451           SV *  lobj;
 452
 453           if (sv_derived_from(ST(0), "version")) {
 454                lobj = SvRV(ST(0));
 455           }
 456           else
 457                Perl_croak(aTHX_ "lobj is not of type version");
 458
 459           PUSHs(sv_2mortal(vstringify(lobj)));
 460
 461           PUTBACK;
 462           return;
 463      }
 464 }
 465
 466 XS(XS_version_numify)
 467 {
 468      dVAR;
 469      dXSARGS;
 470      if (items < 1)
 471           Perl_croak(aTHX_ "Usage: version::numify(lobj, ...)");
 472      SP -= items;
 473      {
 474           SV *  lobj;
 475
 476           if (sv_derived_from(ST(0), "version")) {
 477                lobj = SvRV(ST(0));
 478           }
 479           else
 480                Perl_croak(aTHX_ "lobj is not of type version");
 481
 482           PUSHs(sv_2mortal(vnumify(lobj)));
 483
 484           PUTBACK;
 485           return;
 486      }
 487 }
 488
 489 XS(XS_version_normal)
 490 {
 491      dVAR;
 492      dXSARGS;
 493      if (items < 1)
 494           Perl_croak(aTHX_ "Usage: version::normal(lobj, ...)");
 495      SP -= items;
 496      {
 497           SV *  lobj;
 498
 499           if (sv_derived_from(ST(0), "version")) {
 500                lobj = SvRV(ST(0));
 501           }
 502           else
 503                Perl_croak(aTHX_ "lobj is not of type version");
 504
 505           PUSHs(sv_2mortal(vnormal(lobj)));
 506
 507           PUTBACK;
 508           return;
 509      }
 510 }
 511
 512 XS(XS_version_vcmp)
 513 {
 514      dVAR;
 515      dXSARGS;
 516      if (items < 1)
 517           Perl_croak(aTHX_ "Usage: version::vcmp(lobj, ...)");
 518      SP -= items;
 519      {
 520           SV *  lobj;
 521
 522           if (sv_derived_from(ST(0), "version")) {
 523                lobj = SvRV(ST(0));
 524           }
 525           else
 526                Perl_croak(aTHX_ "lobj is not of type version");
 527
 528           {
 529                SV       *rs;
 530                SV       *rvs;
 531                SV * robj = ST(1);
 532                const IV  swap = (IV)SvIV(ST(2));
 533
 534                if ( ! sv_derived_from(robj, "version") )
 535                {
 536                     robj = new_version(robj);
 537                }
 538                rvs = SvRV(robj);
 539
 540                if ( swap )
 541                {
 542                     rs = newSViv(vcmp(rvs,lobj));
 543                }
 544                else
 545                {
 546                     rs = newSViv(vcmp(lobj,rvs));
 547                }
 548
 549                PUSHs(sv_2mortal(rs));
 550           }
 551
 552           PUTBACK;
 553           return;
 554      }
 555 }
 556
 557 XS(XS_version_boolean)
 558 {
 559     dVAR;
 560     dXSARGS;
 561     if (items < 1)
 562         Perl_croak(aTHX_ "Usage: version::boolean(lobj, ...)");
 563     SP -= items;
 564     if (sv_derived_from(ST(0), "version")) {
 565         SV * const lobj = SvRV(ST(0));
 566         SV * const rs = newSViv( vcmp(lobj,new_version(newSVpvs("0"))) );
 567         PUSHs(sv_2mortal(rs));
 568         PUTBACK;
 569         return;
 570     }
 571     else
 572         Perl_croak(aTHX_ "lobj is not of type version");
 573 }
 574
 575 XS(XS_version_noop)
 576 {
 577     dVAR;
 578     dXSARGS;
 579     if (items < 1)
 580         Perl_croak(aTHX_ "Usage: version::noop(lobj, ...)");
 581     if (sv_derived_from(ST(0), "version"))
 582         Perl_croak(aTHX_ "operation not supported with version object");
 583     else
 584         Perl_croak(aTHX_ "lobj is not of type version");
 585 #ifndef HASATTRIBUTE_NORETURN
 586     XSRETURN_EMPTY;
 587 #endif
 588 }
 589
 590 XS(XS_version_is_alpha)
 591 {
 592     dVAR;
 593     dXSARGS;
 594     if (items != 1)
 595         Perl_croak(aTHX_ "Usage: version::is_alpha(lobj)");
 596     SP -= items;
 597     if (sv_derived_from(ST(0), "version")) {
 598         SV * const lobj = ST(0);
 599         if ( hv_exists((HV*)SvRV(lobj), "alpha", 5 ) )
 600             XSRETURN_YES;
 601         else
 602             XSRETURN_NO;
 603         PUTBACK;
 604         return;
 605     }
 606     else
 607         Perl_croak(aTHX_ "lobj is not of type version");
 608 }
 609
 610 XS(XS_version_qv)
 611 {
 612     dVAR;
 613     dXSARGS;
 614     if (items != 1)
 615         Perl_croak(aTHX_ "Usage: version::qv(ver)");
 616     SP -= items;
 617     {
 618         SV *    ver = ST(0);
 619         if ( !SvVOK(ver) ) { /* only need to do with if not already v-string */
 620             SV * const vs = sv_newmortal();
 621             char *version;
 622             if ( SvNOK(ver) ) /* may get too much accuracy */
 623             {
 624                 char tbuf[64];
 625                 const STRLEN len = my_snprintf(tbuf, sizeof(tbuf), "%.9"NVgf, SvNVX(ver));
 626                 version = savepvn(tbuf, len);
 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      dVAR;
 650      dXSARGS;
 651      if (items != 1)
 652           Perl_croak(aTHX_ "Usage: utf8::is_utf8(sv)");
 653      else {
 654         const SV * const sv = ST(0);
 655             if (SvUTF8(sv))
 656                 XSRETURN_YES;
 657             else
 658                 XSRETURN_NO;
 659      }
 660      XSRETURN_EMPTY;
 661 }
 662
 663 XS(XS_utf8_valid)
 664 {
 665      dVAR;
 666      dXSARGS;
 667      if (items != 1)
 668           Perl_croak(aTHX_ "Usage: utf8::valid(sv)");
 669     else {
 670         SV * const sv = ST(0);
 671         STRLEN len;
 672         const char * const s = SvPV_const(sv,len);
 673         if (!SvUTF8(sv) || is_utf8_string((const U8*)s,len))
 674             XSRETURN_YES;
 675         else
 676             XSRETURN_NO;
 677     }
 678      XSRETURN_EMPTY;
 679 }
 680
 681 XS(XS_utf8_encode)
 682 {
 683     dVAR;
 684     dXSARGS;
 685     if (items != 1)
 686         Perl_croak(aTHX_ "Usage: utf8::encode(sv)");
 687     sv_utf8_encode(ST(0));
 688     XSRETURN_EMPTY;
 689 }
 690
 691 XS(XS_utf8_decode)
 692 {
 693     dVAR;
 694     dXSARGS;
 695     if (items != 1)
 696         Perl_croak(aTHX_ "Usage: utf8::decode(sv)");
 697     else {
 698         SV * const sv = ST(0);
 699         const bool RETVAL = sv_utf8_decode(sv);
 700         ST(0) = boolSV(RETVAL);
 701         sv_2mortal(ST(0));
 702     }
 703     XSRETURN(1);
 704 }
 705
 706 XS(XS_utf8_upgrade)
 707 {
 708     dVAR;
 709     dXSARGS;
 710     if (items != 1)
 711         Perl_croak(aTHX_ "Usage: utf8::upgrade(sv)");
 712     else {
 713         SV * const sv = ST(0);
 714         STRLEN  RETVAL;
 715         dXSTARG;
 716
 717         RETVAL = sv_utf8_upgrade(sv);
 718         XSprePUSH; PUSHi((IV)RETVAL);
 719     }
 720     XSRETURN(1);
 721 }
 722
 723 XS(XS_utf8_downgrade)
 724 {
 725     dVAR;
 726     dXSARGS;
 727     if (items < 1 || items > 2)
 728         Perl_croak(aTHX_ "Usage: utf8::downgrade(sv, failok=0)");
 729     else {
 730         SV * const sv = ST(0);
 731         const bool failok = (items < 2) ? 0 : (int)SvIV(ST(1));
 732         const bool RETVAL = sv_utf8_downgrade(sv, failok);
 733
 734         ST(0) = boolSV(RETVAL);
 735         sv_2mortal(ST(0));
 736     }
 737     XSRETURN(1);
 738 }
 739
 740 XS(XS_utf8_native_to_unicode)
 741 {
 742  dVAR;
 743  dXSARGS;
 744  const UV uv = SvUV(ST(0));
 745
 746  if (items > 1)
 747      Perl_croak(aTHX_ "Usage: utf8::native_to_unicode(sv)");
 748
 749  ST(0) = sv_2mortal(newSViv(NATIVE_TO_UNI(uv)));
 750  XSRETURN(1);
 751 }
 752
 753 XS(XS_utf8_unicode_to_native)
 754 {
 755  dVAR;
 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     dVAR;
 769     dXSARGS;
 770     SV * const sv = SvRV(ST(0));
 771
 772     if (items == 1) {
 773          if (SvREADONLY(sv))
 774              XSRETURN_YES;
 775          else
 776              XSRETURN_NO;
 777     }
 778     else if (items == 2) {
 779         if (SvTRUE(ST(1))) {
 780             SvREADONLY_on(sv);
 781             XSRETURN_YES;
 782         }
 783         else {
 784             /* I hope you really know what you are doing. */
 785             SvREADONLY_off(sv);
 786             XSRETURN_NO;
 787         }
 788     }
 789     XSRETURN_UNDEF; /* Can't happen. */
 790 }
 791
 792 XS(XS_Internals_SvREFCNT)       /* This is dangerous stuff. */
 793 {
 794     dVAR;
 795     dXSARGS;
 796     SV * const sv = SvRV(ST(0));
 797
 798     if (items == 1)
 799          XSRETURN_IV(SvREFCNT(sv) - 1); /* Minus the ref created for us. */
 800     else if (items == 2) {
 801          /* I hope you really know what you are doing. */
 802          SvREFCNT(sv) = SvIV(ST(1));
 803          XSRETURN_IV(SvREFCNT(sv));
 804     }
 805     XSRETURN_UNDEF; /* Can't happen. */
 806 }
 807
 808 XS(XS_Internals_hv_clear_placehold)
 809 {
 810     dVAR;
 811     dXSARGS;
 812
 813     if (items != 1)
 814         Perl_croak(aTHX_ "Usage: UNIVERSAL::hv_clear_placeholders(hv)");
 815     else {
 816         HV * const hv = (HV *) SvRV(ST(0));
 817         hv_clear_placeholders(hv);
 818         XSRETURN(0);
 819     }
 820 }
 821
 822 XS(XS_Regexp_DESTROY)
 823 {
 824     PERL_UNUSED_CONTEXT;
 825     PERL_UNUSED_ARG(cv);
 826 }
 827
 828 XS(XS_PerlIO_get_layers)
 829 {
 830     dVAR;
 831     dXSARGS;
 832     if (items < 1 || items % 2 == 0)
 833         Perl_croak(aTHX_ "Usage: PerlIO_get_layers(filehandle[,args])");
 834 #ifdef USE_PERLIO
 835     {
 836         SV *    sv;
 837         GV *    gv;
 838         IO *    io;
 839         bool    input = TRUE;
 840         bool    details = FALSE;
 841
 842         if (items > 1) {
 843              SV * const *svp;
 844              for (svp = MARK + 2; svp <= SP; svp += 2) {
 845                   SV * const * const varp = svp;
 846                   SV * const * const valp = svp + 1;
 847                   STRLEN klen;
 848                   const char * const key = SvPV_const(*varp, klen);
 849
 850                   switch (*key) {
 851                   case 'i':
 852                        if (klen == 5 && memEQ(key, "input", 5)) {
 853                             input = SvTRUE(*valp);
 854                             break;
 855                        }
 856                        goto fail;
 857                   case 'o':
 858                        if (klen == 6 && memEQ(key, "output", 6)) {
 859                             input = !SvTRUE(*valp);
 860                             break;
 861                        }
 862                        goto fail;
 863                   case 'd':
 864                        if (klen == 7 && memEQ(key, "details", 7)) {
 865                             details = SvTRUE(*valp);
 866                             break;
 867                        }
 868                        goto fail;
 869                   default:
 870                   fail:
 871                        Perl_croak(aTHX_
 872                                   "get_layers: unknown argument '%s'",
 873                                   key);
 874                   }
 875              }
 876
 877              SP -= (items - 1);
 878         }
 879
 880         sv = POPs;
 881         gv = (GV*)sv;
 882
 883         if (!isGV(sv)) {
 884              if (SvROK(sv) && isGV(SvRV(sv)))
 885                   gv = (GV*)SvRV(sv);
 886              else if (SvPOKp(sv))
 887                   gv = gv_fetchsv(sv, 0, SVt_PVIO);
 888         }
 889
 890         if (gv && (io = GvIO(gv))) {
 891              dTARGET;
 892              AV* const av = PerlIO_get_layers(aTHX_ input ?
 893                                         IoIFP(io) : IoOFP(io));
 894              I32 i;
 895              const I32 last = av_len(av);
 896              I32 nitem = 0;
 897
 898              for (i = last; i >= 0; i -= 3) {
 899                   SV * const * const namsvp = av_fetch(av, i - 2, FALSE);
 900                   SV * const * const argsvp = av_fetch(av, i - 1, FALSE);
 901                   SV * const * const flgsvp = av_fetch(av, i,     FALSE);
 902
 903                   const bool namok = namsvp && *namsvp && SvPOK(*namsvp);
 904                   const bool argok = argsvp && *argsvp && SvPOK(*argsvp);
 905                   const bool flgok = flgsvp && *flgsvp && SvIOK(*flgsvp);
 906
 907                   if (details) {
 908                        XPUSHs(namok
 909                               ? newSVpvn(SvPVX_const(*namsvp), SvCUR(*namsvp))
 910                               : &PL_sv_undef);
 911                        XPUSHs(argok
 912                               ? newSVpvn(SvPVX_const(*argsvp), SvCUR(*argsvp))
 913                               : &PL_sv_undef);
 914                        if (flgok)
 915                             XPUSHi(SvIVX(*flgsvp));
 916                        else
 917                             XPUSHs(&PL_sv_undef);
 918                        nitem += 3;
 919                   }
 920                   else {
 921                        if (namok && argok)
 922                             XPUSHs(Perl_newSVpvf(aTHX_ "%"SVf"(%"SVf")",
 923                                                  (void*)*namsvp,
 924                                                  (void*)*argsvp));
 925                        else if (namok)
 926                             XPUSHs(Perl_newSVpvf(aTHX_ "%"SVf,
 927                                                  (void*)*namsvp));
 928                        else
 929                             XPUSHs(&PL_sv_undef);
 930                        nitem++;
 931                        if (flgok) {
 932                             const IV flags = SvIVX(*flgsvp);
 933
 934                             if (flags & PERLIO_F_UTF8) {
 935                                  XPUSHs(newSVpvs("utf8"));
 936                                  nitem++;
 937                             }
 938                        }
 939                   }
 940              }
 941
 942              SvREFCNT_dec(av);
 943
 944              XSRETURN(nitem);
 945         }
 946     }
 947 #endif
 948
 949     XSRETURN(0);
 950 }
 951
 952 XS(XS_Internals_hash_seed)
 953 {
 954     dVAR;
 955     /* Using dXSARGS would also have dITEM and dSP,
 956      * which define 2 unused local variables.  */
 957     dAXMARK;
 958     PERL_UNUSED_ARG(cv);
 959     PERL_UNUSED_VAR(mark);
 960     XSRETURN_UV(PERL_HASH_SEED);
 961 }
 962
 963 XS(XS_Internals_rehash_seed)
 964 {
 965     dVAR;
 966     /* Using dXSARGS would also have dITEM and dSP,
 967      * which define 2 unused local variables.  */
 968     dAXMARK;
 969     PERL_UNUSED_ARG(cv);
 970     PERL_UNUSED_VAR(mark);
 971     XSRETURN_UV(PL_rehash_seed);
 972 }
 973
 974 XS(XS_Internals_HvREHASH)       /* Subject to change  */
 975 {
 976     dVAR;
 977     dXSARGS;
 978     if (SvROK(ST(0))) {
 979         const HV * const hv = (HV *) SvRV(ST(0));
 980         if (items == 1 && SvTYPE(hv) == SVt_PVHV) {
 981             if (HvREHASH(hv))
 982                 XSRETURN_YES;
 983             else
 984                 XSRETURN_NO;
 985         }
 986     }
 987     Perl_croak(aTHX_ "Internals::HvREHASH $hashref");
 988 }
 989
 990 XS(XS_Internals_inc_sub_generation)
 991 {
 992     dVAR;
 993     /* Using dXSARGS would also have dITEM and dSP,
 994      * which define 2 unused local variables.  */
 995     dAXMARK;
 996     PERL_UNUSED_ARG(cv);
 997     PERL_UNUSED_VAR(mark);
 998     ++PL_sub_generation;
 999     XSRETURN_EMPTY;
1000 }
1001
1002 /*
1003  * Local variables:
1004  * c-indentation-style: bsd
1005  * c-basic-offset: 4
1006  * indent-tabs-mode: t
1007  * End:
1008  *
1009  * ex: set ts=8 sts=4 sw=4 noet:
1010  */