3 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
4 * 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Larry Wall and others
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.
12 * I sit beside the fire and think
13 * of all that I have seen.
16 * [p.278 of _The Lord of the Rings_, II/iii: "The Ring Goes South"]
20 =head1 Hash Manipulation Functions
22 A HV structure represents a Perl hash. It consists mainly of an array
23 of pointers, each of which points to a linked list of HE structures. The
24 array is indexed by the hash function of the key, so each linked list
25 represents all the hash entries with the same hash value. Each HE contains
26 a pointer to the actual value, plus a pointer to a HEK structure which
27 holds the key and hash value.
35 #define PERL_HASH_INTERNAL_ACCESS
38 #define HV_MAX_LENGTH_BEFORE_SPLIT 14
40 static const char S_strtab_error[]
41 = "Cannot modify shared string table in hv_%s";
47 /* We could generate this at compile time via (another) auxiliary C
49 const size_t arena_size = Perl_malloc_good_size(PERL_ARENA_SIZE);
50 HE* he = (HE*) Perl_get_arena(aTHX_ arena_size, HE_SVSLOT);
51 HE * const heend = &he[arena_size / sizeof(HE) - 1];
53 PL_body_roots[HE_SVSLOT] = he;
55 HeNEXT(he) = (HE*)(he + 1);
63 #define new_HE() (HE*)safemalloc(sizeof(HE))
64 #define del_HE(p) safefree((char*)p)
73 void ** const root = &PL_body_roots[HE_SVSLOT];
83 #define new_HE() new_he()
86 HeNEXT(p) = (HE*)(PL_body_roots[HE_SVSLOT]); \
87 PL_body_roots[HE_SVSLOT] = p; \
95 S_save_hek_flags(const char *str, I32 len, U32 hash, int flags)
97 const int flags_masked = flags & HVhek_MASK;
101 PERL_ARGS_ASSERT_SAVE_HEK_FLAGS;
103 Newx(k, HEK_BASESIZE + len + 2, char);
105 Copy(str, HEK_KEY(hek), len, char);
106 HEK_KEY(hek)[len] = 0;
108 HEK_HASH(hek) = hash;
109 HEK_FLAGS(hek) = (unsigned char)flags_masked | HVhek_UNSHARED;
111 if (flags & HVhek_FREEKEY)
116 /* free the pool of temporary HE/HEK pairs returned by hv_fetch_ent
120 Perl_free_tied_hv_pool(pTHX)
123 HE *he = PL_hv_fetch_ent_mh;
126 Safefree(HeKEY_hek(he));
130 PL_hv_fetch_ent_mh = NULL;
133 #if defined(USE_ITHREADS)
135 Perl_hek_dup(pTHX_ HEK *source, CLONE_PARAMS* param)
137 HEK *shared = (HEK*)ptr_table_fetch(PL_ptr_table, source);
139 PERL_ARGS_ASSERT_HEK_DUP;
140 PERL_UNUSED_ARG(param);
143 /* We already shared this hash key. */
144 (void)share_hek_hek(shared);
148 = share_hek_flags(HEK_KEY(source), HEK_LEN(source),
149 HEK_HASH(source), HEK_FLAGS(source));
150 ptr_table_store(PL_ptr_table, source, shared);
156 Perl_he_dup(pTHX_ const HE *e, bool shared, CLONE_PARAMS* param)
160 PERL_ARGS_ASSERT_HE_DUP;
164 /* look for it in the table first */
165 ret = (HE*)ptr_table_fetch(PL_ptr_table, e);
169 /* create anew and remember what it is */
171 ptr_table_store(PL_ptr_table, e, ret);
173 HeNEXT(ret) = he_dup(HeNEXT(e),shared, param);
174 if (HeKLEN(e) == HEf_SVKEY) {
176 Newx(k, HEK_BASESIZE + sizeof(const SV *), char);
177 HeKEY_hek(ret) = (HEK*)k;
178 HeKEY_sv(ret) = SvREFCNT_inc(sv_dup(HeKEY_sv(e), param));
181 /* This is hek_dup inlined, which seems to be important for speed
183 HEK * const source = HeKEY_hek(e);
184 HEK *shared = (HEK*)ptr_table_fetch(PL_ptr_table, source);
187 /* We already shared this hash key. */
188 (void)share_hek_hek(shared);
192 = share_hek_flags(HEK_KEY(source), HEK_LEN(source),
193 HEK_HASH(source), HEK_FLAGS(source));
194 ptr_table_store(PL_ptr_table, source, shared);
196 HeKEY_hek(ret) = shared;
199 HeKEY_hek(ret) = save_hek_flags(HeKEY(e), HeKLEN(e), HeHASH(e),
201 HeVAL(ret) = SvREFCNT_inc(sv_dup(HeVAL(e), param));
204 #endif /* USE_ITHREADS */
207 S_hv_notallowed(pTHX_ int flags, const char *key, I32 klen,
210 SV * const sv = sv_newmortal();
212 PERL_ARGS_ASSERT_HV_NOTALLOWED;
214 if (!(flags & HVhek_FREEKEY)) {
215 sv_setpvn(sv, key, klen);
218 /* Need to free saved eventually assign to mortal SV */
219 /* XXX is this line an error ???: SV *sv = sv_newmortal(); */
220 sv_usepvn(sv, (char *) key, klen);
222 if (flags & HVhek_UTF8) {
225 Perl_croak(aTHX_ msg, SVfARG(sv));
228 /* (klen == HEf_SVKEY) is special for MAGICAL hv entries, meaning key slot
234 Stores an SV in a hash. The hash key is specified as C<key> and C<klen> is
235 the length of the key. The C<hash> parameter is the precomputed hash
236 value; if it is zero then Perl will compute it. The return value will be
237 NULL if the operation failed or if the value did not need to be actually
238 stored within the hash (as in the case of tied hashes). Otherwise it can
239 be dereferenced to get the original C<SV*>. Note that the caller is
240 responsible for suitably incrementing the reference count of C<val> before
241 the call, and decrementing it if the function returned NULL. Effectively
242 a successful hv_store takes ownership of one reference to C<val>. This is
243 usually what you want; a newly created SV has a reference count of one, so
244 if all your code does is create SVs then store them in a hash, hv_store
245 will own the only reference to the new SV, and your code doesn't need to do
246 anything further to tidy up. hv_store is not implemented as a call to
247 hv_store_ent, and does not create a temporary SV for the key, so if your
248 key data is not already in SV form then use hv_store in preference to
251 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
252 information on how to use this function on tied hashes.
254 =for apidoc hv_store_ent
256 Stores C<val> in a hash. The hash key is specified as C<key>. The C<hash>
257 parameter is the precomputed hash value; if it is zero then Perl will
258 compute it. The return value is the new hash entry so created. It will be
259 NULL if the operation failed or if the value did not need to be actually
260 stored within the hash (as in the case of tied hashes). Otherwise the
261 contents of the return value can be accessed using the C<He?> macros
262 described here. Note that the caller is responsible for suitably
263 incrementing the reference count of C<val> before the call, and
264 decrementing it if the function returned NULL. Effectively a successful
265 hv_store_ent takes ownership of one reference to C<val>. This is
266 usually what you want; a newly created SV has a reference count of one, so
267 if all your code does is create SVs then store them in a hash, hv_store
268 will own the only reference to the new SV, and your code doesn't need to do
269 anything further to tidy up. Note that hv_store_ent only reads the C<key>;
270 unlike C<val> it does not take ownership of it, so maintaining the correct
271 reference count on C<key> is entirely the caller's responsibility. hv_store
272 is not implemented as a call to hv_store_ent, and does not create a temporary
273 SV for the key, so if your key data is not already in SV form then use
274 hv_store in preference to hv_store_ent.
276 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
277 information on how to use this function on tied hashes.
279 =for apidoc hv_exists
281 Returns a boolean indicating whether the specified hash key exists. The
282 C<klen> is the length of the key.
286 Returns the SV which corresponds to the specified key in the hash. The
287 C<klen> is the length of the key. If C<lval> is set then the fetch will be
288 part of a store. Check that the return value is non-null before
289 dereferencing it to an C<SV*>.
291 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
292 information on how to use this function on tied hashes.
294 =for apidoc hv_exists_ent
296 Returns a boolean indicating whether the specified hash key exists. C<hash>
297 can be a valid precomputed hash value, or 0 to ask for it to be
303 /* returns an HE * structure with the all fields set */
304 /* note that hent_val will be a mortal sv for MAGICAL hashes */
306 =for apidoc hv_fetch_ent
308 Returns the hash entry which corresponds to the specified key in the hash.
309 C<hash> must be a valid precomputed hash number for the given C<key>, or 0
310 if you want the function to compute it. IF C<lval> is set then the fetch
311 will be part of a store. Make sure the return value is non-null before
312 accessing it. The return value when C<tb> is a tied hash is a pointer to a
313 static location, so be sure to make a copy of the structure if you need to
316 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
317 information on how to use this function on tied hashes.
322 /* Common code for hv_delete()/hv_exists()/hv_fetch()/hv_store() */
324 Perl_hv_common_key_len(pTHX_ HV *hv, const char *key, I32 klen_i32,
325 const int action, SV *val, const U32 hash)
330 PERL_ARGS_ASSERT_HV_COMMON_KEY_LEN;
339 return hv_common(hv, NULL, key, klen, flags, action, val, hash);
343 Perl_hv_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
344 int flags, int action, SV *val, register U32 hash)
353 const int return_svp = action & HV_FETCH_JUST_SV;
357 if (SvTYPE(hv) == SVTYPEMASK)
360 assert(SvTYPE(hv) == SVt_PVHV);
362 if (SvSMAGICAL(hv) && SvGMAGICAL(hv) && !(action & HV_DISABLE_UVAR_XKEY)) {
364 if ((mg = mg_find((const SV *)hv, PERL_MAGIC_uvar))) {
365 struct ufuncs * const uf = (struct ufuncs *)mg->mg_ptr;
366 if (uf->uf_set == NULL) {
367 SV* obj = mg->mg_obj;
370 keysv = newSVpvn_flags(key, klen, SVs_TEMP |
371 ((flags & HVhek_UTF8)
375 mg->mg_obj = keysv; /* pass key */
376 uf->uf_index = action; /* pass action */
377 magic_getuvar(MUTABLE_SV(hv), mg);
378 keysv = mg->mg_obj; /* may have changed */
381 /* If the key may have changed, then we need to invalidate
382 any passed-in computed hash value. */
388 if (flags & HVhek_FREEKEY)
390 key = SvPV_const(keysv, klen);
392 is_utf8 = (SvUTF8(keysv) != 0);
394 is_utf8 = ((flags & HVhek_UTF8) ? TRUE : FALSE);
397 if (action & HV_DELETE) {
398 return (void *) hv_delete_common(hv, keysv, key, klen,
399 flags | (is_utf8 ? HVhek_UTF8 : 0),
403 xhv = (XPVHV*)SvANY(hv);
405 if (SvRMAGICAL(hv) && !(action & (HV_FETCH_ISSTORE|HV_FETCH_ISEXISTS))) {
406 if (mg_find((const SV *)hv, PERL_MAGIC_tied)
407 || SvGMAGICAL((const SV *)hv))
409 /* FIXME should be able to skimp on the HE/HEK here when
410 HV_FETCH_JUST_SV is true. */
412 keysv = newSVpvn_utf8(key, klen, is_utf8);
414 keysv = newSVsv(keysv);
417 mg_copy(MUTABLE_SV(hv), sv, (char *)keysv, HEf_SVKEY);
419 /* grab a fake HE/HEK pair from the pool or make a new one */
420 entry = PL_hv_fetch_ent_mh;
422 PL_hv_fetch_ent_mh = HeNEXT(entry);
426 Newx(k, HEK_BASESIZE + sizeof(const SV *), char);
427 HeKEY_hek(entry) = (HEK*)k;
429 HeNEXT(entry) = NULL;
430 HeSVKEY_set(entry, keysv);
432 sv_upgrade(sv, SVt_PVLV);
434 /* so we can free entry when freeing sv */
435 LvTARG(sv) = MUTABLE_SV(entry);
437 /* XXX remove at some point? */
438 if (flags & HVhek_FREEKEY)
442 return entry ? (void *) &HeVAL(entry) : NULL;
444 return (void *) entry;
446 #ifdef ENV_IS_CASELESS
447 else if (mg_find((const SV *)hv, PERL_MAGIC_env)) {
449 for (i = 0; i < klen; ++i)
450 if (isLOWER(key[i])) {
451 /* Would be nice if we had a routine to do the
452 copy and upercase in a single pass through. */
453 const char * const nkey = strupr(savepvn(key,klen));
454 /* Note that this fetch is for nkey (the uppercased
455 key) whereas the store is for key (the original) */
456 void *result = hv_common(hv, NULL, nkey, klen,
457 HVhek_FREEKEY, /* free nkey */
458 0 /* non-LVAL fetch */
459 | HV_DISABLE_UVAR_XKEY
462 0 /* compute hash */);
463 if (!result && (action & HV_FETCH_LVALUE)) {
464 /* This call will free key if necessary.
465 Do it this way to encourage compiler to tail
467 result = hv_common(hv, keysv, key, klen, flags,
469 | HV_DISABLE_UVAR_XKEY
473 if (flags & HVhek_FREEKEY)
481 else if (SvRMAGICAL(hv) && (action & HV_FETCH_ISEXISTS)) {
482 if (mg_find((const SV *)hv, PERL_MAGIC_tied)
483 || SvGMAGICAL((const SV *)hv)) {
484 /* I don't understand why hv_exists_ent has svret and sv,
485 whereas hv_exists only had one. */
486 SV * const svret = sv_newmortal();
489 if (keysv || is_utf8) {
491 keysv = newSVpvn_utf8(key, klen, TRUE);
493 keysv = newSVsv(keysv);
495 mg_copy(MUTABLE_SV(hv), sv, (char *)sv_2mortal(keysv), HEf_SVKEY);
497 mg_copy(MUTABLE_SV(hv), sv, key, klen);
499 if (flags & HVhek_FREEKEY)
501 magic_existspack(svret, mg_find(sv, PERL_MAGIC_tiedelem));
502 /* This cast somewhat evil, but I'm merely using NULL/
503 not NULL to return the boolean exists.
504 And I know hv is not NULL. */
505 return SvTRUE(svret) ? (void *)hv : NULL;
507 #ifdef ENV_IS_CASELESS
508 else if (mg_find((const SV *)hv, PERL_MAGIC_env)) {
509 /* XXX This code isn't UTF8 clean. */
510 char * const keysave = (char * const)key;
511 /* Will need to free this, so set FREEKEY flag. */
512 key = savepvn(key,klen);
513 key = (const char*)strupr((char*)key);
518 if (flags & HVhek_FREEKEY) {
521 flags |= HVhek_FREEKEY;
525 else if (action & HV_FETCH_ISSTORE) {
528 hv_magic_check (hv, &needs_copy, &needs_store);
530 const bool save_taint = PL_tainted;
531 if (keysv || is_utf8) {
533 keysv = newSVpvn_utf8(key, klen, TRUE);
536 PL_tainted = SvTAINTED(keysv);
537 keysv = sv_2mortal(newSVsv(keysv));
538 mg_copy(MUTABLE_SV(hv), val, (char*)keysv, HEf_SVKEY);
540 mg_copy(MUTABLE_SV(hv), val, key, klen);
543 TAINT_IF(save_taint);
545 if (flags & HVhek_FREEKEY)
549 #ifdef ENV_IS_CASELESS
550 else if (mg_find((const SV *)hv, PERL_MAGIC_env)) {
551 /* XXX This code isn't UTF8 clean. */
552 const char *keysave = key;
553 /* Will need to free this, so set FREEKEY flag. */
554 key = savepvn(key,klen);
555 key = (const char*)strupr((char*)key);
560 if (flags & HVhek_FREEKEY) {
563 flags |= HVhek_FREEKEY;
571 if ((action & (HV_FETCH_LVALUE | HV_FETCH_ISSTORE))
572 #ifdef DYNAMIC_ENV_FETCH /* if it's an %ENV lookup, we may get it on the fly */
573 || (SvRMAGICAL((const SV *)hv)
574 && mg_find((const SV *)hv, PERL_MAGIC_env))
579 PERL_HV_ARRAY_ALLOC_BYTES(xhv->xhv_max+1 /* HvMAX(hv)+1 */),
581 HvARRAY(hv) = (HE**)array;
583 #ifdef DYNAMIC_ENV_FETCH
584 else if (action & HV_FETCH_ISEXISTS) {
585 /* for an %ENV exists, if we do an insert it's by a recursive
586 store call, so avoid creating HvARRAY(hv) right now. */
590 /* XXX remove at some point? */
591 if (flags & HVhek_FREEKEY)
599 char * const keysave = (char *)key;
600 key = (char*)bytes_from_utf8((U8*)key, &klen, &is_utf8);
604 flags &= ~HVhek_UTF8;
605 if (key != keysave) {
606 if (flags & HVhek_FREEKEY)
608 flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
609 /* If the caller calculated a hash, it was on the sequence of
610 octets that are the UTF-8 form. We've now changed the sequence
611 of octets stored to that of the equivalent byte representation,
612 so the hash we need is different. */
618 PERL_HASH_INTERNAL(hash, key, klen);
619 /* We don't have a pointer to the hv, so we have to replicate the
620 flag into every HEK, so that hv_iterkeysv can see it. */
621 /* And yes, you do need this even though you are not "storing" because
622 you can flip the flags below if doing an lval lookup. (And that
623 was put in to give the semantics Andreas was expecting.) */
624 flags |= HVhek_REHASH;
626 if (keysv && (SvIsCOW_shared_hash(keysv))) {
627 hash = SvSHARED_HASH(keysv);
629 PERL_HASH(hash, key, klen);
633 masked_flags = (flags & HVhek_MASK);
635 #ifdef DYNAMIC_ENV_FETCH
636 if (!HvARRAY(hv)) entry = NULL;
640 entry = (HvARRAY(hv))[hash & (I32) HvMAX(hv)];
642 for (; entry; entry = HeNEXT(entry)) {
643 if (HeHASH(entry) != hash) /* strings can't be equal */
645 if (HeKLEN(entry) != (I32)klen)
647 if (HeKEY(entry) != key && memNE(HeKEY(entry),key,klen)) /* is this it? */
649 if ((HeKFLAGS(entry) ^ masked_flags) & HVhek_UTF8)
652 if (action & (HV_FETCH_LVALUE|HV_FETCH_ISSTORE)) {
653 if (HeKFLAGS(entry) != masked_flags) {
654 /* We match if HVhek_UTF8 bit in our flags and hash key's
655 match. But if entry was set previously with HVhek_WASUTF8
656 and key now doesn't (or vice versa) then we should change
657 the key's flag, as this is assignment. */
658 if (HvSHAREKEYS(hv)) {
659 /* Need to swap the key we have for a key with the flags we
660 need. As keys are shared we can't just write to the
661 flag, so we share the new one, unshare the old one. */
662 HEK * const new_hek = share_hek_flags(key, klen, hash,
664 unshare_hek (HeKEY_hek(entry));
665 HeKEY_hek(entry) = new_hek;
667 else if (hv == PL_strtab) {
668 /* PL_strtab is usually the only hash without HvSHAREKEYS,
669 so putting this test here is cheap */
670 if (flags & HVhek_FREEKEY)
672 Perl_croak(aTHX_ S_strtab_error,
673 action & HV_FETCH_LVALUE ? "fetch" : "store");
676 HeKFLAGS(entry) = masked_flags;
677 if (masked_flags & HVhek_ENABLEHVKFLAGS)
680 if (HeVAL(entry) == &PL_sv_placeholder) {
681 /* yes, can store into placeholder slot */
682 if (action & HV_FETCH_LVALUE) {
684 /* This preserves behaviour with the old hv_fetch
685 implementation which at this point would bail out
686 with a break; (at "if we find a placeholder, we
687 pretend we haven't found anything")
689 That break mean that if a placeholder were found, it
690 caused a call into hv_store, which in turn would
691 check magic, and if there is no magic end up pretty
692 much back at this point (in hv_store's code). */
695 /* LVAL fetch which actaully needs a store. */
697 HvPLACEHOLDERS(hv)--;
700 if (val != &PL_sv_placeholder)
701 HvPLACEHOLDERS(hv)--;
704 } else if (action & HV_FETCH_ISSTORE) {
705 SvREFCNT_dec(HeVAL(entry));
708 } else if (HeVAL(entry) == &PL_sv_placeholder) {
709 /* if we find a placeholder, we pretend we haven't found
713 if (flags & HVhek_FREEKEY)
716 return entry ? (void *) &HeVAL(entry) : NULL;
720 #ifdef DYNAMIC_ENV_FETCH /* %ENV lookup? If so, try to fetch the value now */
721 if (!(action & HV_FETCH_ISSTORE)
722 && SvRMAGICAL((const SV *)hv)
723 && mg_find((const SV *)hv, PERL_MAGIC_env)) {
725 const char * const env = PerlEnv_ENVgetenv_len(key,&len);
727 sv = newSVpvn(env,len);
729 return hv_common(hv, keysv, key, klen, flags,
730 HV_FETCH_ISSTORE|HV_DISABLE_UVAR_XKEY|return_svp,
736 if (!entry && SvREADONLY(hv) && !(action & HV_FETCH_ISEXISTS)) {
737 hv_notallowed(flags, key, klen,
738 "Attempt to access disallowed key '%"SVf"' in"
739 " a restricted hash");
741 if (!(action & (HV_FETCH_LVALUE|HV_FETCH_ISSTORE))) {
742 /* Not doing some form of store, so return failure. */
743 if (flags & HVhek_FREEKEY)
747 if (action & HV_FETCH_LVALUE) {
750 /* At this point the old hv_fetch code would call to hv_store,
751 which in turn might do some tied magic. So we need to make that
752 magic check happen. */
753 /* gonna assign to this, so it better be there */
754 /* If a fetch-as-store fails on the fetch, then the action is to
755 recurse once into "hv_store". If we didn't do this, then that
756 recursive call would call the key conversion routine again.
757 However, as we replace the original key with the converted
758 key, this would result in a double conversion, which would show
759 up as a bug if the conversion routine is not idempotent. */
760 return hv_common(hv, keysv, key, klen, flags,
761 HV_FETCH_ISSTORE|HV_DISABLE_UVAR_XKEY|return_svp,
763 /* XXX Surely that could leak if the fetch-was-store fails?
764 Just like the hv_fetch. */
768 /* Welcome to hv_store... */
771 /* Not sure if we can get here. I think the only case of oentry being
772 NULL is for %ENV with dynamic env fetch. But that should disappear
773 with magic in the previous code. */
776 PERL_HV_ARRAY_ALLOC_BYTES(xhv->xhv_max+1 /* HvMAX(hv)+1 */),
778 HvARRAY(hv) = (HE**)array;
781 oentry = &(HvARRAY(hv))[hash & (I32) xhv->xhv_max];
784 /* share_hek_flags will do the free for us. This might be considered
787 HeKEY_hek(entry) = share_hek_flags(key, klen, hash, flags);
788 else if (hv == PL_strtab) {
789 /* PL_strtab is usually the only hash without HvSHAREKEYS, so putting
790 this test here is cheap */
791 if (flags & HVhek_FREEKEY)
793 Perl_croak(aTHX_ S_strtab_error,
794 action & HV_FETCH_LVALUE ? "fetch" : "store");
796 else /* gotta do the real thing */
797 HeKEY_hek(entry) = save_hek_flags(key, klen, hash, flags);
799 HeNEXT(entry) = *oentry;
802 if (val == &PL_sv_placeholder)
803 HvPLACEHOLDERS(hv)++;
804 if (masked_flags & HVhek_ENABLEHVKFLAGS)
808 const HE *counter = HeNEXT(entry);
810 xhv->xhv_keys++; /* HvTOTALKEYS(hv)++ */
811 if (!counter) { /* initial entry? */
812 xhv->xhv_fill++; /* HvFILL(hv)++ */
813 } else if (xhv->xhv_keys > (IV)xhv->xhv_max) {
815 } else if(!HvREHASH(hv)) {
818 while ((counter = HeNEXT(counter)))
821 if (n_links > HV_MAX_LENGTH_BEFORE_SPLIT) {
822 /* Use only the old HvKEYS(hv) > HvMAX(hv) condition to limit
823 bucket splits on a rehashed hash, as we're not going to
824 split it again, and if someone is lucky (evil) enough to
825 get all the keys in one list they could exhaust our memory
826 as we repeatedly double the number of buckets on every
827 entry. Linear search feels a less worse thing to do. */
834 return entry ? (void *) &HeVAL(entry) : NULL;
836 return (void *) entry;
840 S_hv_magic_check(HV *hv, bool *needs_copy, bool *needs_store)
842 const MAGIC *mg = SvMAGIC(hv);
844 PERL_ARGS_ASSERT_HV_MAGIC_CHECK;
849 if (isUPPER(mg->mg_type)) {
851 if (mg->mg_type == PERL_MAGIC_tied) {
852 *needs_store = FALSE;
853 return; /* We've set all there is to set. */
856 mg = mg->mg_moremagic;
861 =for apidoc hv_scalar
863 Evaluates the hash in scalar context and returns the result. Handles magic when the hash is tied.
869 Perl_hv_scalar(pTHX_ HV *hv)
873 PERL_ARGS_ASSERT_HV_SCALAR;
875 if (SvRMAGICAL(hv)) {
876 MAGIC * const mg = mg_find((const SV *)hv, PERL_MAGIC_tied);
878 return magic_scalarpack(hv, mg);
882 if (HvFILL((const HV *)hv))
883 Perl_sv_setpvf(aTHX_ sv, "%ld/%ld",
884 (long)HvFILL(hv), (long)HvMAX(hv) + 1);
892 =for apidoc hv_delete
894 Deletes a key/value pair in the hash. The value SV is removed from the
895 hash and returned to the caller. The C<klen> is the length of the key.
896 The C<flags> value will normally be zero; if set to G_DISCARD then NULL
899 =for apidoc hv_delete_ent
901 Deletes a key/value pair in the hash. The value SV is removed from the
902 hash and returned to the caller. The C<flags> value will normally be zero;
903 if set to G_DISCARD then NULL will be returned. C<hash> can be a valid
904 precomputed hash value, or 0 to ask for it to be computed.
910 S_hv_delete_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
911 int k_flags, I32 d_flags, U32 hash)
916 register HE **oentry;
917 HE *const *first_entry;
918 bool is_utf8 = (k_flags & HVhek_UTF8) ? TRUE : FALSE;
921 if (SvRMAGICAL(hv)) {
924 hv_magic_check (hv, &needs_copy, &needs_store);
928 entry = (HE *) hv_common(hv, keysv, key, klen,
929 k_flags & ~HVhek_FREEKEY,
930 HV_FETCH_LVALUE|HV_DISABLE_UVAR_XKEY,
932 sv = entry ? HeVAL(entry) : NULL;
938 if (mg_find(sv, PERL_MAGIC_tiedelem)) {
939 /* No longer an element */
940 sv_unmagic(sv, PERL_MAGIC_tiedelem);
943 return NULL; /* element cannot be deleted */
945 #ifdef ENV_IS_CASELESS
946 else if (mg_find((const SV *)hv, PERL_MAGIC_env)) {
947 /* XXX This code isn't UTF8 clean. */
948 keysv = newSVpvn_flags(key, klen, SVs_TEMP);
949 if (k_flags & HVhek_FREEKEY) {
952 key = strupr(SvPVX(keysv));
961 xhv = (XPVHV*)SvANY(hv);
966 const char * const keysave = key;
967 key = (char*)bytes_from_utf8((U8*)key, &klen, &is_utf8);
970 k_flags |= HVhek_UTF8;
972 k_flags &= ~HVhek_UTF8;
973 if (key != keysave) {
974 if (k_flags & HVhek_FREEKEY) {
975 /* This shouldn't happen if our caller does what we expect,
976 but strictly the API allows it. */
979 k_flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
981 HvHASKFLAGS_on(MUTABLE_SV(hv));
985 PERL_HASH_INTERNAL(hash, key, klen);
987 if (keysv && (SvIsCOW_shared_hash(keysv))) {
988 hash = SvSHARED_HASH(keysv);
990 PERL_HASH(hash, key, klen);
994 masked_flags = (k_flags & HVhek_MASK);
996 first_entry = oentry = &(HvARRAY(hv))[hash & (I32) HvMAX(hv)];
998 for (; entry; oentry = &HeNEXT(entry), entry = *oentry) {
1000 if (HeHASH(entry) != hash) /* strings can't be equal */
1002 if (HeKLEN(entry) != (I32)klen)
1004 if (HeKEY(entry) != key && memNE(HeKEY(entry),key,klen)) /* is this it? */
1006 if ((HeKFLAGS(entry) ^ masked_flags) & HVhek_UTF8)
1009 if (hv == PL_strtab) {
1010 if (k_flags & HVhek_FREEKEY)
1012 Perl_croak(aTHX_ S_strtab_error, "delete");
1015 /* if placeholder is here, it's already been deleted.... */
1016 if (HeVAL(entry) == &PL_sv_placeholder) {
1017 if (k_flags & HVhek_FREEKEY)
1021 if (SvREADONLY(hv) && HeVAL(entry) && SvREADONLY(HeVAL(entry))) {
1022 hv_notallowed(k_flags, key, klen,
1023 "Attempt to delete readonly key '%"SVf"' from"
1024 " a restricted hash");
1026 if (k_flags & HVhek_FREEKEY)
1029 if (d_flags & G_DISCARD)
1032 sv = sv_2mortal(HeVAL(entry));
1033 HeVAL(entry) = &PL_sv_placeholder;
1037 * If a restricted hash, rather than really deleting the entry, put
1038 * a placeholder there. This marks the key as being "approved", so
1039 * we can still access via not-really-existing key without raising
1042 if (SvREADONLY(hv)) {
1043 SvREFCNT_dec(HeVAL(entry));
1044 HeVAL(entry) = &PL_sv_placeholder;
1045 /* We'll be saving this slot, so the number of allocated keys
1046 * doesn't go down, but the number placeholders goes up */
1047 HvPLACEHOLDERS(hv)++;
1049 *oentry = HeNEXT(entry);
1051 xhv->xhv_fill--; /* HvFILL(hv)-- */
1053 if (SvOOK(hv) && entry == HvAUX(hv)->xhv_eiter /* HvEITER(hv) */)
1056 hv_free_ent(hv, entry);
1057 xhv->xhv_keys--; /* HvTOTALKEYS(hv)-- */
1058 if (xhv->xhv_keys == 0)
1059 HvHASKFLAGS_off(hv);
1063 if (SvREADONLY(hv)) {
1064 hv_notallowed(k_flags, key, klen,
1065 "Attempt to delete disallowed key '%"SVf"' from"
1066 " a restricted hash");
1069 if (k_flags & HVhek_FREEKEY)
1075 S_hsplit(pTHX_ HV *hv)
1078 register XPVHV* const xhv = (XPVHV*)SvANY(hv);
1079 const I32 oldsize = (I32) xhv->xhv_max+1; /* HvMAX(hv)+1 (sick) */
1080 register I32 newsize = oldsize * 2;
1082 char *a = (char*) HvARRAY(hv);
1084 register HE **oentry;
1085 int longest_chain = 0;
1088 PERL_ARGS_ASSERT_HSPLIT;
1090 /*PerlIO_printf(PerlIO_stderr(), "hsplit called for %p which had %d\n",
1091 (void*)hv, (int) oldsize);*/
1093 if (HvPLACEHOLDERS_get(hv) && !SvREADONLY(hv)) {
1094 /* Can make this clear any placeholders first for non-restricted hashes,
1095 even though Storable rebuilds restricted hashes by putting in all the
1096 placeholders (first) before turning on the readonly flag, because
1097 Storable always pre-splits the hash. */
1098 hv_clear_placeholders(hv);
1102 #if defined(STRANGE_MALLOC) || defined(MYMALLOC)
1103 Renew(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1104 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1110 Move(&a[oldsize * sizeof(HE*)], &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1113 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1114 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1119 Copy(HvARRAY(hv), a, oldsize * sizeof(HE*), char);
1121 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1123 if (oldsize >= 64) {
1124 offer_nice_chunk(HvARRAY(hv),
1125 PERL_HV_ARRAY_ALLOC_BYTES(oldsize)
1126 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0));
1129 Safefree(HvARRAY(hv));
1133 Zero(&a[oldsize * sizeof(HE*)], (newsize-oldsize) * sizeof(HE*), char); /* zero 2nd half*/
1134 xhv->xhv_max = --newsize; /* HvMAX(hv) = --newsize */
1135 HvARRAY(hv) = (HE**) a;
1138 for (i=0; i<oldsize; i++,aep++) {
1139 int left_length = 0;
1140 int right_length = 0;
1144 if (!*aep) /* non-existent */
1147 for (oentry = aep, entry = *aep; entry; entry = *oentry) {
1148 if ((HeHASH(entry) & newsize) != (U32)i) {
1149 *oentry = HeNEXT(entry);
1150 HeNEXT(entry) = *bep;
1152 xhv->xhv_fill++; /* HvFILL(hv)++ */
1158 oentry = &HeNEXT(entry);
1162 if (!*aep) /* everything moved */
1163 xhv->xhv_fill--; /* HvFILL(hv)-- */
1164 /* I think we don't actually need to keep track of the longest length,
1165 merely flag if anything is too long. But for the moment while
1166 developing this code I'll track it. */
1167 if (left_length > longest_chain)
1168 longest_chain = left_length;
1169 if (right_length > longest_chain)
1170 longest_chain = right_length;
1174 /* Pick your policy for "hashing isn't working" here: */
1175 if (longest_chain <= HV_MAX_LENGTH_BEFORE_SPLIT /* split worked? */
1180 if (hv == PL_strtab) {
1181 /* Urg. Someone is doing something nasty to the string table.
1186 /* Awooga. Awooga. Pathological data. */
1187 /*PerlIO_printf(PerlIO_stderr(), "%p %d of %d with %d/%d buckets\n", (void*)hv,
1188 longest_chain, HvTOTALKEYS(hv), HvFILL(hv), 1+HvMAX(hv));*/
1191 Newxz(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1192 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1194 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1197 was_shared = HvSHAREKEYS(hv);
1200 HvSHAREKEYS_off(hv);
1205 for (i=0; i<newsize; i++,aep++) {
1206 register HE *entry = *aep;
1208 /* We're going to trash this HE's next pointer when we chain it
1209 into the new hash below, so store where we go next. */
1210 HE * const next = HeNEXT(entry);
1215 PERL_HASH_INTERNAL(hash, HeKEY(entry), HeKLEN(entry));
1220 = save_hek_flags(HeKEY(entry), HeKLEN(entry),
1221 hash, HeKFLAGS(entry));
1222 unshare_hek (HeKEY_hek(entry));
1223 HeKEY_hek(entry) = new_hek;
1225 /* Not shared, so simply write the new hash in. */
1226 HeHASH(entry) = hash;
1228 /*PerlIO_printf(PerlIO_stderr(), "%d ", HeKFLAGS(entry));*/
1229 HEK_REHASH_on(HeKEY_hek(entry));
1230 /*PerlIO_printf(PerlIO_stderr(), "%d\n", HeKFLAGS(entry));*/
1232 /* Copy oentry to the correct new chain. */
1233 bep = ((HE**)a) + (hash & (I32) xhv->xhv_max);
1235 xhv->xhv_fill++; /* HvFILL(hv)++ */
1236 HeNEXT(entry) = *bep;
1242 Safefree (HvARRAY(hv));
1243 HvARRAY(hv) = (HE **)a;
1247 Perl_hv_ksplit(pTHX_ HV *hv, IV newmax)
1250 register XPVHV* xhv = (XPVHV*)SvANY(hv);
1251 const I32 oldsize = (I32) xhv->xhv_max+1; /* HvMAX(hv)+1 (sick) */
1252 register I32 newsize;
1257 register HE **oentry;
1259 PERL_ARGS_ASSERT_HV_KSPLIT;
1261 newsize = (I32) newmax; /* possible truncation here */
1262 if (newsize != newmax || newmax <= oldsize)
1264 while ((newsize & (1 + ~newsize)) != newsize) {
1265 newsize &= ~(newsize & (1 + ~newsize)); /* get proper power of 2 */
1267 if (newsize < newmax)
1269 if (newsize < newmax)
1270 return; /* overflow detection */
1272 a = (char *) HvARRAY(hv);
1275 #if defined(STRANGE_MALLOC) || defined(MYMALLOC)
1276 Renew(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1277 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1283 Copy(&a[oldsize * sizeof(HE*)], &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1286 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1287 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1292 Copy(HvARRAY(hv), a, oldsize * sizeof(HE*), char);
1294 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1296 if (oldsize >= 64) {
1297 offer_nice_chunk(HvARRAY(hv),
1298 PERL_HV_ARRAY_ALLOC_BYTES(oldsize)
1299 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0));
1302 Safefree(HvARRAY(hv));
1305 Zero(&a[oldsize * sizeof(HE*)], (newsize-oldsize) * sizeof(HE*), char); /* zero 2nd half*/
1308 Newxz(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize), char);
1310 xhv->xhv_max = --newsize; /* HvMAX(hv) = --newsize */
1311 HvARRAY(hv) = (HE **) a;
1312 if (!xhv->xhv_fill /* !HvFILL(hv) */) /* skip rest if no entries */
1316 for (i=0; i<oldsize; i++,aep++) {
1317 if (!*aep) /* non-existent */
1319 for (oentry = aep, entry = *aep; entry; entry = *oentry) {
1320 register I32 j = (HeHASH(entry) & newsize);
1324 *oentry = HeNEXT(entry);
1325 if (!(HeNEXT(entry) = aep[j]))
1326 xhv->xhv_fill++; /* HvFILL(hv)++ */
1331 oentry = &HeNEXT(entry);
1333 if (!*aep) /* everything moved */
1334 xhv->xhv_fill--; /* HvFILL(hv)-- */
1339 Perl_newHVhv(pTHX_ HV *ohv)
1341 HV * const hv = newHV();
1342 STRLEN hv_max, hv_fill;
1344 if (!ohv || (hv_fill = HvFILL(ohv)) == 0)
1346 hv_max = HvMAX(ohv);
1348 if (!SvMAGICAL((const SV *)ohv)) {
1349 /* It's an ordinary hash, so copy it fast. AMS 20010804 */
1351 const bool shared = !!HvSHAREKEYS(ohv);
1352 HE **ents, ** const oents = (HE **)HvARRAY(ohv);
1354 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(hv_max+1), char);
1357 /* In each bucket... */
1358 for (i = 0; i <= hv_max; i++) {
1360 HE *oent = oents[i];
1367 /* Copy the linked list of entries. */
1368 for (; oent; oent = HeNEXT(oent)) {
1369 const U32 hash = HeHASH(oent);
1370 const char * const key = HeKEY(oent);
1371 const STRLEN len = HeKLEN(oent);
1372 const int flags = HeKFLAGS(oent);
1373 HE * const ent = new_HE();
1375 HeVAL(ent) = newSVsv(HeVAL(oent));
1377 = shared ? share_hek_flags(key, len, hash, flags)
1378 : save_hek_flags(key, len, hash, flags);
1389 HvFILL(hv) = hv_fill;
1390 HvTOTALKEYS(hv) = HvTOTALKEYS(ohv);
1394 /* Iterate over ohv, copying keys and values one at a time. */
1396 const I32 riter = HvRITER_get(ohv);
1397 HE * const eiter = HvEITER_get(ohv);
1399 /* Can we use fewer buckets? (hv_max is always 2^n-1) */
1400 while (hv_max && hv_max + 1 >= hv_fill * 2)
1401 hv_max = hv_max / 2;
1405 while ((entry = hv_iternext_flags(ohv, 0))) {
1406 (void)hv_store_flags(hv, HeKEY(entry), HeKLEN(entry),
1407 newSVsv(HeVAL(entry)), HeHASH(entry),
1410 HvRITER_set(ohv, riter);
1411 HvEITER_set(ohv, eiter);
1417 /* A rather specialised version of newHVhv for copying %^H, ensuring all the
1418 magic stays on it. */
1420 Perl_hv_copy_hints_hv(pTHX_ HV *const ohv)
1422 HV * const hv = newHV();
1425 if (ohv && (hv_fill = HvFILL(ohv))) {
1426 STRLEN hv_max = HvMAX(ohv);
1428 const I32 riter = HvRITER_get(ohv);
1429 HE * const eiter = HvEITER_get(ohv);
1431 while (hv_max && hv_max + 1 >= hv_fill * 2)
1432 hv_max = hv_max / 2;
1436 while ((entry = hv_iternext_flags(ohv, 0))) {
1437 SV *const sv = newSVsv(HeVAL(entry));
1438 sv_magic(sv, NULL, PERL_MAGIC_hintselem,
1439 (char *)newSVhek (HeKEY_hek(entry)), HEf_SVKEY);
1440 (void)hv_store_flags(hv, HeKEY(entry), HeKLEN(entry),
1441 sv, HeHASH(entry), HeKFLAGS(entry));
1443 HvRITER_set(ohv, riter);
1444 HvEITER_set(ohv, eiter);
1446 hv_magic(hv, NULL, PERL_MAGIC_hints);
1451 Perl_hv_free_ent(pTHX_ HV *hv, register HE *entry)
1456 PERL_ARGS_ASSERT_HV_FREE_ENT;
1461 if (val && isGV(val) && isGV_with_GP(val) && GvCVu(val) && HvNAME_get(hv))
1462 mro_method_changed_in(hv); /* deletion of method from stash */
1464 if (HeKLEN(entry) == HEf_SVKEY) {
1465 SvREFCNT_dec(HeKEY_sv(entry));
1466 Safefree(HeKEY_hek(entry));
1468 else if (HvSHAREKEYS(hv))
1469 unshare_hek(HeKEY_hek(entry));
1471 Safefree(HeKEY_hek(entry));
1476 Perl_hv_delayfree_ent(pTHX_ HV *hv, register HE *entry)
1480 PERL_ARGS_ASSERT_HV_DELAYFREE_ENT;
1484 /* SvREFCNT_inc to counter the SvREFCNT_dec in hv_free_ent */
1485 sv_2mortal(SvREFCNT_inc(HeVAL(entry))); /* free between statements */
1486 if (HeKLEN(entry) == HEf_SVKEY) {
1487 sv_2mortal(SvREFCNT_inc(HeKEY_sv(entry)));
1489 hv_free_ent(hv, entry);
1493 =for apidoc hv_clear
1495 Clears a hash, making it empty.
1501 Perl_hv_clear(pTHX_ HV *hv)
1504 register XPVHV* xhv;
1508 DEBUG_A(Perl_hv_assert(aTHX_ hv));
1510 xhv = (XPVHV*)SvANY(hv);
1512 if (SvREADONLY(hv) && HvARRAY(hv) != NULL) {
1513 /* restricted hash: convert all keys to placeholders */
1515 for (i = 0; i <= xhv->xhv_max; i++) {
1516 HE *entry = (HvARRAY(hv))[i];
1517 for (; entry; entry = HeNEXT(entry)) {
1518 /* not already placeholder */
1519 if (HeVAL(entry) != &PL_sv_placeholder) {
1520 if (HeVAL(entry) && SvREADONLY(HeVAL(entry))) {
1521 SV* const keysv = hv_iterkeysv(entry);
1523 "Attempt to delete readonly key '%"SVf"' from a restricted hash",
1526 SvREFCNT_dec(HeVAL(entry));
1527 HeVAL(entry) = &PL_sv_placeholder;
1528 HvPLACEHOLDERS(hv)++;
1536 HvPLACEHOLDERS_set(hv, 0);
1538 Zero(HvARRAY(hv), xhv->xhv_max+1 /* HvMAX(hv)+1 */, HE*);
1541 mg_clear(MUTABLE_SV(hv));
1543 HvHASKFLAGS_off(hv);
1548 mro_isa_changed_in(hv);
1549 HvEITER_set(hv, NULL);
1554 =for apidoc hv_clear_placeholders
1556 Clears any placeholders from a hash. If a restricted hash has any of its keys
1557 marked as readonly and the key is subsequently deleted, the key is not actually
1558 deleted but is marked by assigning it a value of &PL_sv_placeholder. This tags
1559 it so it will be ignored by future operations such as iterating over the hash,
1560 but will still allow the hash to have a value reassigned to the key at some
1561 future point. This function clears any such placeholder keys from the hash.
1562 See Hash::Util::lock_keys() for an example of its use.
1568 Perl_hv_clear_placeholders(pTHX_ HV *hv)
1571 const U32 items = (U32)HvPLACEHOLDERS_get(hv);
1573 PERL_ARGS_ASSERT_HV_CLEAR_PLACEHOLDERS;
1576 clear_placeholders(hv, items);
1580 S_clear_placeholders(pTHX_ HV *hv, U32 items)
1585 PERL_ARGS_ASSERT_CLEAR_PLACEHOLDERS;
1592 /* Loop down the linked list heads */
1594 HE **oentry = &(HvARRAY(hv))[i];
1597 while ((entry = *oentry)) {
1598 if (HeVAL(entry) == &PL_sv_placeholder) {
1599 *oentry = HeNEXT(entry);
1600 if (first && !*oentry)
1601 HvFILL(hv)--; /* This linked list is now empty. */
1602 if (entry == HvEITER_get(hv))
1605 hv_free_ent(hv, entry);
1609 HvTOTALKEYS(hv) -= (IV)HvPLACEHOLDERS_get(hv);
1610 if (HvKEYS(hv) == 0)
1611 HvHASKFLAGS_off(hv);
1612 HvPLACEHOLDERS_set(hv, 0);
1616 oentry = &HeNEXT(entry);
1621 /* You can't get here, hence assertion should always fail. */
1622 assert (items == 0);
1627 S_hfreeentries(pTHX_ HV *hv)
1629 /* This is the array that we're going to restore */
1630 HE **const orig_array = HvARRAY(hv);
1634 PERL_ARGS_ASSERT_HFREEENTRIES;
1640 /* If the hash is actually a symbol table with a name, look after the
1642 struct xpvhv_aux *iter = HvAUX(hv);
1644 name = iter->xhv_name;
1645 iter->xhv_name = NULL;
1650 /* orig_array remains unchanged throughout the loop. If after freeing all
1651 the entries it turns out that one of the little blighters has triggered
1652 an action that has caused HvARRAY to be re-allocated, then we set
1653 array to the new HvARRAY, and try again. */
1656 /* This is the one we're going to try to empty. First time round
1657 it's the original array. (Hopefully there will only be 1 time
1659 HE ** const array = HvARRAY(hv);
1662 /* Because we have taken xhv_name out, the only allocated pointer
1663 in the aux structure that might exist is the backreference array.
1668 struct mro_meta *meta;
1669 struct xpvhv_aux *iter = HvAUX(hv);
1670 /* If there are weak references to this HV, we need to avoid
1671 freeing them up here. In particular we need to keep the AV
1672 visible as what we're deleting might well have weak references
1673 back to this HV, so the for loop below may well trigger
1674 the removal of backreferences from this array. */
1676 if (iter->xhv_backreferences) {
1677 /* So donate them to regular backref magic to keep them safe.
1678 The sv_magic will increase the reference count of the AV,
1679 so we need to drop it first. */
1680 SvREFCNT_dec(iter->xhv_backreferences);
1681 if (AvFILLp(iter->xhv_backreferences) == -1) {
1682 /* Turns out that the array is empty. Just free it. */
1683 SvREFCNT_dec(iter->xhv_backreferences);
1686 sv_magic(MUTABLE_SV(hv),
1687 MUTABLE_SV(iter->xhv_backreferences),
1688 PERL_MAGIC_backref, NULL, 0);
1690 iter->xhv_backreferences = NULL;
1693 entry = iter->xhv_eiter; /* HvEITER(hv) */
1694 if (entry && HvLAZYDEL(hv)) { /* was deleted earlier? */
1696 hv_free_ent(hv, entry);
1698 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1699 iter->xhv_eiter = NULL; /* HvEITER(hv) = NULL */
1701 if((meta = iter->xhv_mro_meta)) {
1702 if (meta->mro_linear_all) {
1703 SvREFCNT_dec(MUTABLE_SV(meta->mro_linear_all));
1704 meta->mro_linear_all = NULL;
1705 /* This is just acting as a shortcut pointer. */
1706 meta->mro_linear_current = NULL;
1707 } else if (meta->mro_linear_current) {
1708 /* Only the current MRO is stored, so this owns the data.
1710 SvREFCNT_dec(meta->mro_linear_current);
1711 meta->mro_linear_current = NULL;
1713 if(meta->mro_nextmethod) SvREFCNT_dec(meta->mro_nextmethod);
1714 SvREFCNT_dec(meta->isa);
1716 iter->xhv_mro_meta = NULL;
1719 /* There are now no allocated pointers in the aux structure. */
1721 SvFLAGS(hv) &= ~SVf_OOK; /* Goodbye, aux structure. */
1722 /* What aux structure? */
1725 /* make everyone else think the array is empty, so that the destructors
1726 * called for freed entries can't recusively mess with us */
1729 ((XPVHV*) SvANY(hv))->xhv_keys = 0;
1733 /* Loop down the linked list heads */
1734 HE *entry = array[i];
1737 register HE * const oentry = entry;
1738 entry = HeNEXT(entry);
1739 hv_free_ent(hv, oentry);
1743 /* As there are no allocated pointers in the aux structure, it's now
1744 safe to free the array we just cleaned up, if it's not the one we're
1745 going to put back. */
1746 if (array != orig_array) {
1751 /* Good. No-one added anything this time round. */
1756 /* Someone attempted to iterate or set the hash name while we had
1757 the array set to 0. We'll catch backferences on the next time
1758 round the while loop. */
1759 assert(HvARRAY(hv));
1761 if (HvAUX(hv)->xhv_name) {
1762 unshare_hek_or_pvn(HvAUX(hv)->xhv_name, 0, 0, 0);
1766 if (--attempts == 0) {
1767 Perl_die(aTHX_ "panic: hfreeentries failed to free hash - something is repeatedly re-creating entries");
1771 HvARRAY(hv) = orig_array;
1773 /* If the hash was actually a symbol table, put the name back. */
1775 /* We have restored the original array. If name is non-NULL, then
1776 the original array had an aux structure at the end. So this is
1778 SvFLAGS(hv) |= SVf_OOK;
1779 HvAUX(hv)->xhv_name = name;
1784 =for apidoc hv_undef
1792 Perl_hv_undef(pTHX_ HV *hv)
1795 register XPVHV* xhv;
1800 DEBUG_A(Perl_hv_assert(aTHX_ hv));
1801 xhv = (XPVHV*)SvANY(hv);
1803 if ((name = HvNAME_get(hv)) && !PL_dirty)
1804 mro_isa_changed_in(hv);
1809 (void)hv_delete(PL_stashcache, name, HvNAMELEN_get(hv), G_DISCARD);
1810 hv_name_set(hv, NULL, 0, 0);
1812 SvFLAGS(hv) &= ~SVf_OOK;
1813 Safefree(HvARRAY(hv));
1814 xhv->xhv_max = 7; /* HvMAX(hv) = 7 (it's a normal hash) */
1816 HvPLACEHOLDERS_set(hv, 0);
1819 mg_clear(MUTABLE_SV(hv));
1822 static struct xpvhv_aux*
1823 S_hv_auxinit(HV *hv) {
1824 struct xpvhv_aux *iter;
1827 PERL_ARGS_ASSERT_HV_AUXINIT;
1830 Newxz(array, PERL_HV_ARRAY_ALLOC_BYTES(HvMAX(hv) + 1)
1831 + sizeof(struct xpvhv_aux), char);
1833 array = (char *) HvARRAY(hv);
1834 Renew(array, PERL_HV_ARRAY_ALLOC_BYTES(HvMAX(hv) + 1)
1835 + sizeof(struct xpvhv_aux), char);
1837 HvARRAY(hv) = (HE**) array;
1838 /* SvOOK_on(hv) attacks the IV flags. */
1839 SvFLAGS(hv) |= SVf_OOK;
1842 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1843 iter->xhv_eiter = NULL; /* HvEITER(hv) = NULL */
1845 iter->xhv_backreferences = 0;
1846 iter->xhv_mro_meta = NULL;
1851 =for apidoc hv_iterinit
1853 Prepares a starting point to traverse a hash table. Returns the number of
1854 keys in the hash (i.e. the same as C<HvKEYS(tb)>). The return value is
1855 currently only meaningful for hashes without tie magic.
1857 NOTE: Before version 5.004_65, C<hv_iterinit> used to return the number of
1858 hash buckets that happen to be in use. If you still need that esoteric
1859 value, you can get it through the macro C<HvFILL(tb)>.
1866 Perl_hv_iterinit(pTHX_ HV *hv)
1868 PERL_ARGS_ASSERT_HV_ITERINIT;
1870 /* FIXME: Are we not NULL, or do we croak? Place bets now! */
1873 Perl_croak(aTHX_ "Bad hash");
1876 struct xpvhv_aux * const iter = HvAUX(hv);
1877 HE * const entry = iter->xhv_eiter; /* HvEITER(hv) */
1878 if (entry && HvLAZYDEL(hv)) { /* was deleted earlier? */
1880 hv_free_ent(hv, entry);
1882 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1883 iter->xhv_eiter = NULL; /* HvEITER(hv) = NULL */
1888 /* used to be xhv->xhv_fill before 5.004_65 */
1889 return HvTOTALKEYS(hv);
1893 Perl_hv_riter_p(pTHX_ HV *hv) {
1894 struct xpvhv_aux *iter;
1896 PERL_ARGS_ASSERT_HV_RITER_P;
1899 Perl_croak(aTHX_ "Bad hash");
1901 iter = SvOOK(hv) ? HvAUX(hv) : hv_auxinit(hv);
1902 return &(iter->xhv_riter);
1906 Perl_hv_eiter_p(pTHX_ HV *hv) {
1907 struct xpvhv_aux *iter;
1909 PERL_ARGS_ASSERT_HV_EITER_P;
1912 Perl_croak(aTHX_ "Bad hash");
1914 iter = SvOOK(hv) ? HvAUX(hv) : hv_auxinit(hv);
1915 return &(iter->xhv_eiter);
1919 Perl_hv_riter_set(pTHX_ HV *hv, I32 riter) {
1920 struct xpvhv_aux *iter;
1922 PERL_ARGS_ASSERT_HV_RITER_SET;
1925 Perl_croak(aTHX_ "Bad hash");
1933 iter = hv_auxinit(hv);
1935 iter->xhv_riter = riter;
1939 Perl_hv_eiter_set(pTHX_ HV *hv, HE *eiter) {
1940 struct xpvhv_aux *iter;
1942 PERL_ARGS_ASSERT_HV_EITER_SET;
1945 Perl_croak(aTHX_ "Bad hash");
1950 /* 0 is the default so don't go malloc()ing a new structure just to
1955 iter = hv_auxinit(hv);
1957 iter->xhv_eiter = eiter;
1961 Perl_hv_name_set(pTHX_ HV *hv, const char *name, U32 len, U32 flags)
1964 struct xpvhv_aux *iter;
1967 PERL_ARGS_ASSERT_HV_NAME_SET;
1968 PERL_UNUSED_ARG(flags);
1971 Perl_croak(aTHX_ "panic: hv name too long (%"UVuf")", (UV) len);
1975 if (iter->xhv_name) {
1976 unshare_hek_or_pvn(iter->xhv_name, 0, 0, 0);
1982 iter = hv_auxinit(hv);
1984 PERL_HASH(hash, name, len);
1985 iter->xhv_name = name ? share_hek(name, len, hash) : NULL;
1989 Perl_hv_backreferences_p(pTHX_ HV *hv) {
1990 struct xpvhv_aux * const iter = SvOOK(hv) ? HvAUX(hv) : hv_auxinit(hv);
1992 PERL_ARGS_ASSERT_HV_BACKREFERENCES_P;
1993 PERL_UNUSED_CONTEXT;
1995 return &(iter->xhv_backreferences);
1999 Perl_hv_kill_backrefs(pTHX_ HV *hv) {
2002 PERL_ARGS_ASSERT_HV_KILL_BACKREFS;
2007 av = HvAUX(hv)->xhv_backreferences;
2010 HvAUX(hv)->xhv_backreferences = 0;
2011 Perl_sv_kill_backrefs(aTHX_ MUTABLE_SV(hv), av);
2017 hv_iternext is implemented as a macro in hv.h
2019 =for apidoc hv_iternext
2021 Returns entries from a hash iterator. See C<hv_iterinit>.
2023 You may call C<hv_delete> or C<hv_delete_ent> on the hash entry that the
2024 iterator currently points to, without losing your place or invalidating your
2025 iterator. Note that in this case the current entry is deleted from the hash
2026 with your iterator holding the last reference to it. Your iterator is flagged
2027 to free the entry on the next call to C<hv_iternext>, so you must not discard
2028 your iterator immediately else the entry will leak - call C<hv_iternext> to
2029 trigger the resource deallocation.
2031 =for apidoc hv_iternext_flags
2033 Returns entries from a hash iterator. See C<hv_iterinit> and C<hv_iternext>.
2034 The C<flags> value will normally be zero; if HV_ITERNEXT_WANTPLACEHOLDERS is
2035 set the placeholders keys (for restricted hashes) will be returned in addition
2036 to normal keys. By default placeholders are automatically skipped over.
2037 Currently a placeholder is implemented with a value that is
2038 C<&Perl_sv_placeholder>. Note that the implementation of placeholders and
2039 restricted hashes may change, and the implementation currently is
2040 insufficiently abstracted for any change to be tidy.
2046 Perl_hv_iternext_flags(pTHX_ HV *hv, I32 flags)
2049 register XPVHV* xhv;
2053 struct xpvhv_aux *iter;
2055 PERL_ARGS_ASSERT_HV_ITERNEXT_FLAGS;
2058 Perl_croak(aTHX_ "Bad hash");
2060 xhv = (XPVHV*)SvANY(hv);
2063 /* Too many things (well, pp_each at least) merrily assume that you can
2064 call iv_iternext without calling hv_iterinit, so we'll have to deal
2070 oldentry = entry = iter->xhv_eiter; /* HvEITER(hv) */
2071 if (SvMAGICAL(hv) && SvRMAGICAL(hv)) {
2072 if ( ( mg = mg_find((const SV *)hv, PERL_MAGIC_tied) ) ) {
2073 SV * const key = sv_newmortal();
2075 sv_setsv(key, HeSVKEY_force(entry));
2076 SvREFCNT_dec(HeSVKEY(entry)); /* get rid of previous key */
2082 /* one HE per MAGICAL hash */
2083 iter->xhv_eiter = entry = new_HE(); /* HvEITER(hv) = new_HE() */
2085 Newxz(k, HEK_BASESIZE + sizeof(const SV *), char);
2087 HeKEY_hek(entry) = hek;
2088 HeKLEN(entry) = HEf_SVKEY;
2090 magic_nextpack(MUTABLE_SV(hv),mg,key);
2092 /* force key to stay around until next time */
2093 HeSVKEY_set(entry, SvREFCNT_inc_simple_NN(key));
2094 return entry; /* beware, hent_val is not set */
2097 SvREFCNT_dec(HeVAL(entry));
2098 Safefree(HeKEY_hek(entry));
2100 iter->xhv_eiter = NULL; /* HvEITER(hv) = NULL */
2104 #if defined(DYNAMIC_ENV_FETCH) && !defined(__riscos__) /* set up %ENV for iteration */
2105 if (!entry && SvRMAGICAL((const SV *)hv)
2106 && mg_find((const SV *)hv, PERL_MAGIC_env)) {
2109 /* The prime_env_iter() on VMS just loaded up new hash values
2110 * so the iteration count needs to be reset back to the beginning
2114 oldentry = entry = iter->xhv_eiter; /* HvEITER(hv) */
2119 /* hv_iterint now ensures this. */
2120 assert (HvARRAY(hv));
2122 /* At start of hash, entry is NULL. */
2125 entry = HeNEXT(entry);
2126 if (!(flags & HV_ITERNEXT_WANTPLACEHOLDERS)) {
2128 * Skip past any placeholders -- don't want to include them in
2131 while (entry && HeVAL(entry) == &PL_sv_placeholder) {
2132 entry = HeNEXT(entry);
2137 /* OK. Come to the end of the current list. Grab the next one. */
2139 iter->xhv_riter++; /* HvRITER(hv)++ */
2140 if (iter->xhv_riter > (I32)xhv->xhv_max /* HvRITER(hv) > HvMAX(hv) */) {
2141 /* There is no next one. End of the hash. */
2142 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
2145 entry = (HvARRAY(hv))[iter->xhv_riter];
2147 if (!(flags & HV_ITERNEXT_WANTPLACEHOLDERS)) {
2148 /* If we have an entry, but it's a placeholder, don't count it.
2150 while (entry && HeVAL(entry) == &PL_sv_placeholder)
2151 entry = HeNEXT(entry);
2153 /* Will loop again if this linked list starts NULL
2154 (for HV_ITERNEXT_WANTPLACEHOLDERS)
2155 or if we run through it and find only placeholders. */
2158 if (oldentry && HvLAZYDEL(hv)) { /* was deleted earlier? */
2160 hv_free_ent(hv, oldentry);
2163 /*if (HvREHASH(hv) && entry && !HeKREHASH(entry))
2164 PerlIO_printf(PerlIO_stderr(), "Awooga %p %p\n", (void*)hv, (void*)entry);*/
2166 iter->xhv_eiter = entry; /* HvEITER(hv) = entry */
2171 =for apidoc hv_iterkey
2173 Returns the key from the current position of the hash iterator. See
2180 Perl_hv_iterkey(pTHX_ register HE *entry, I32 *retlen)
2182 PERL_ARGS_ASSERT_HV_ITERKEY;
2184 if (HeKLEN(entry) == HEf_SVKEY) {
2186 char * const p = SvPV(HeKEY_sv(entry), len);
2191 *retlen = HeKLEN(entry);
2192 return HeKEY(entry);
2196 /* unlike hv_iterval(), this always returns a mortal copy of the key */
2198 =for apidoc hv_iterkeysv
2200 Returns the key as an C<SV*> from the current position of the hash
2201 iterator. The return value will always be a mortal copy of the key. Also
2208 Perl_hv_iterkeysv(pTHX_ register HE *entry)
2210 PERL_ARGS_ASSERT_HV_ITERKEYSV;
2212 return sv_2mortal(newSVhek(HeKEY_hek(entry)));
2216 =for apidoc hv_iterval
2218 Returns the value from the current position of the hash iterator. See
2225 Perl_hv_iterval(pTHX_ HV *hv, register HE *entry)
2227 PERL_ARGS_ASSERT_HV_ITERVAL;
2229 if (SvRMAGICAL(hv)) {
2230 if (mg_find((const SV *)hv, PERL_MAGIC_tied)) {
2231 SV* const sv = sv_newmortal();
2232 if (HeKLEN(entry) == HEf_SVKEY)
2233 mg_copy(MUTABLE_SV(hv), sv, (char*)HeKEY_sv(entry), HEf_SVKEY);
2235 mg_copy(MUTABLE_SV(hv), sv, HeKEY(entry), HeKLEN(entry));
2239 return HeVAL(entry);
2243 =for apidoc hv_iternextsv
2245 Performs an C<hv_iternext>, C<hv_iterkey>, and C<hv_iterval> in one
2252 Perl_hv_iternextsv(pTHX_ HV *hv, char **key, I32 *retlen)
2254 HE * const he = hv_iternext_flags(hv, 0);
2256 PERL_ARGS_ASSERT_HV_ITERNEXTSV;
2260 *key = hv_iterkey(he, retlen);
2261 return hv_iterval(hv, he);
2268 =for apidoc hv_magic
2270 Adds magic to a hash. See C<sv_magic>.
2275 /* possibly free a shared string if no one has access to it
2276 * len and hash must both be valid for str.
2279 Perl_unsharepvn(pTHX_ const char *str, I32 len, U32 hash)
2281 unshare_hek_or_pvn (NULL, str, len, hash);
2286 Perl_unshare_hek(pTHX_ HEK *hek)
2289 unshare_hek_or_pvn(hek, NULL, 0, 0);
2292 /* possibly free a shared string if no one has access to it
2293 hek if non-NULL takes priority over the other 3, else str, len and hash
2294 are used. If so, len and hash must both be valid for str.
2297 S_unshare_hek_or_pvn(pTHX_ const HEK *hek, const char *str, I32 len, U32 hash)
2300 register XPVHV* xhv;
2302 register HE **oentry;
2304 bool is_utf8 = FALSE;
2306 const char * const save = str;
2307 struct shared_he *he = NULL;
2310 /* Find the shared he which is just before us in memory. */
2311 he = (struct shared_he *)(((char *)hek)
2312 - STRUCT_OFFSET(struct shared_he,
2315 /* Assert that the caller passed us a genuine (or at least consistent)
2317 assert (he->shared_he_he.hent_hek == hek);
2320 if (he->shared_he_he.he_valu.hent_refcount - 1) {
2321 --he->shared_he_he.he_valu.hent_refcount;
2322 UNLOCK_STRTAB_MUTEX;
2325 UNLOCK_STRTAB_MUTEX;
2327 hash = HEK_HASH(hek);
2328 } else if (len < 0) {
2329 STRLEN tmplen = -len;
2331 /* See the note in hv_fetch(). --jhi */
2332 str = (char*)bytes_from_utf8((U8*)str, &tmplen, &is_utf8);
2335 k_flags = HVhek_UTF8;
2337 k_flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
2340 /* what follows was the moral equivalent of:
2341 if ((Svp = hv_fetch(PL_strtab, tmpsv, FALSE, hash))) {
2343 hv_delete(PL_strtab, str, len, G_DISCARD, hash);
2345 xhv = (XPVHV*)SvANY(PL_strtab);
2346 /* assert(xhv_array != 0) */
2348 first = oentry = &(HvARRAY(PL_strtab))[hash & (I32) HvMAX(PL_strtab)];
2350 const HE *const he_he = &(he->shared_he_he);
2351 for (entry = *oentry; entry; oentry = &HeNEXT(entry), entry = *oentry) {
2356 const int flags_masked = k_flags & HVhek_MASK;
2357 for (entry = *oentry; entry; oentry = &HeNEXT(entry), entry = *oentry) {
2358 if (HeHASH(entry) != hash) /* strings can't be equal */
2360 if (HeKLEN(entry) != len)
2362 if (HeKEY(entry) != str && memNE(HeKEY(entry),str,len)) /* is this it? */
2364 if (HeKFLAGS(entry) != flags_masked)
2371 if (--entry->he_valu.hent_refcount == 0) {
2372 *oentry = HeNEXT(entry);
2374 /* There are now no entries in our slot. */
2375 xhv->xhv_fill--; /* HvFILL(hv)-- */
2378 xhv->xhv_keys--; /* HvTOTALKEYS(hv)-- */
2382 UNLOCK_STRTAB_MUTEX;
2383 if (!entry && ckWARN_d(WARN_INTERNAL))
2384 Perl_warner(aTHX_ packWARN(WARN_INTERNAL),
2385 "Attempt to free non-existent shared string '%s'%s"
2387 hek ? HEK_KEY(hek) : str,
2388 ((k_flags & HVhek_UTF8) ? " (utf8)" : "") pTHX__VALUE);
2389 if (k_flags & HVhek_FREEKEY)
2393 /* get a (constant) string ptr from the global string table
2394 * string will get added if it is not already there.
2395 * len and hash must both be valid for str.
2398 Perl_share_hek(pTHX_ const char *str, I32 len, register U32 hash)
2400 bool is_utf8 = FALSE;
2402 const char * const save = str;
2404 PERL_ARGS_ASSERT_SHARE_HEK;
2407 STRLEN tmplen = -len;
2409 /* See the note in hv_fetch(). --jhi */
2410 str = (char*)bytes_from_utf8((U8*)str, &tmplen, &is_utf8);
2412 /* If we were able to downgrade here, then than means that we were passed
2413 in a key which only had chars 0-255, but was utf8 encoded. */
2416 /* If we found we were able to downgrade the string to bytes, then
2417 we should flag that it needs upgrading on keys or each. Also flag
2418 that we need share_hek_flags to free the string. */
2420 flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
2423 return share_hek_flags (str, len, hash, flags);
2427 S_share_hek_flags(pTHX_ const char *str, I32 len, register U32 hash, int flags)
2431 const int flags_masked = flags & HVhek_MASK;
2432 const U32 hindex = hash & (I32) HvMAX(PL_strtab);
2433 register XPVHV * const xhv = (XPVHV*)SvANY(PL_strtab);
2435 PERL_ARGS_ASSERT_SHARE_HEK_FLAGS;
2437 /* what follows is the moral equivalent of:
2439 if (!(Svp = hv_fetch(PL_strtab, str, len, FALSE)))
2440 hv_store(PL_strtab, str, len, NULL, hash);
2442 Can't rehash the shared string table, so not sure if it's worth
2443 counting the number of entries in the linked list
2446 /* assert(xhv_array != 0) */
2448 entry = (HvARRAY(PL_strtab))[hindex];
2449 for (;entry; entry = HeNEXT(entry)) {
2450 if (HeHASH(entry) != hash) /* strings can't be equal */
2452 if (HeKLEN(entry) != len)
2454 if (HeKEY(entry) != str && memNE(HeKEY(entry),str,len)) /* is this it? */
2456 if (HeKFLAGS(entry) != flags_masked)
2462 /* What used to be head of the list.
2463 If this is NULL, then we're the first entry for this slot, which
2464 means we need to increate fill. */
2465 struct shared_he *new_entry;
2468 HE **const head = &HvARRAY(PL_strtab)[hindex];
2469 HE *const next = *head;
2471 /* We don't actually store a HE from the arena and a regular HEK.
2472 Instead we allocate one chunk of memory big enough for both,
2473 and put the HEK straight after the HE. This way we can find the
2474 HEK directly from the HE.
2477 Newx(k, STRUCT_OFFSET(struct shared_he,
2478 shared_he_hek.hek_key[0]) + len + 2, char);
2479 new_entry = (struct shared_he *)k;
2480 entry = &(new_entry->shared_he_he);
2481 hek = &(new_entry->shared_he_hek);
2483 Copy(str, HEK_KEY(hek), len, char);
2484 HEK_KEY(hek)[len] = 0;
2486 HEK_HASH(hek) = hash;
2487 HEK_FLAGS(hek) = (unsigned char)flags_masked;
2489 /* Still "point" to the HEK, so that other code need not know what
2491 HeKEY_hek(entry) = hek;
2492 entry->he_valu.hent_refcount = 0;
2493 HeNEXT(entry) = next;
2496 xhv->xhv_keys++; /* HvTOTALKEYS(hv)++ */
2497 if (!next) { /* initial entry? */
2498 xhv->xhv_fill++; /* HvFILL(hv)++ */
2499 } else if (xhv->xhv_keys > (IV)xhv->xhv_max /* HvKEYS(hv) > HvMAX(hv) */) {
2504 ++entry->he_valu.hent_refcount;
2505 UNLOCK_STRTAB_MUTEX;
2507 if (flags & HVhek_FREEKEY)
2510 return HeKEY_hek(entry);
2514 Perl_hv_placeholders_p(pTHX_ HV *hv)
2517 MAGIC *mg = mg_find((const SV *)hv, PERL_MAGIC_rhash);
2519 PERL_ARGS_ASSERT_HV_PLACEHOLDERS_P;
2522 mg = sv_magicext(MUTABLE_SV(hv), 0, PERL_MAGIC_rhash, 0, 0, 0);
2525 Perl_die(aTHX_ "panic: hv_placeholders_p");
2528 return &(mg->mg_len);
2533 Perl_hv_placeholders_get(pTHX_ const HV *hv)
2536 MAGIC * const mg = mg_find((const SV *)hv, PERL_MAGIC_rhash);
2538 PERL_ARGS_ASSERT_HV_PLACEHOLDERS_GET;
2540 return mg ? mg->mg_len : 0;
2544 Perl_hv_placeholders_set(pTHX_ HV *hv, I32 ph)
2547 MAGIC * const mg = mg_find((const SV *)hv, PERL_MAGIC_rhash);
2549 PERL_ARGS_ASSERT_HV_PLACEHOLDERS_SET;
2554 if (!sv_magicext(MUTABLE_SV(hv), 0, PERL_MAGIC_rhash, 0, 0, ph))
2555 Perl_die(aTHX_ "panic: hv_placeholders_set");
2557 /* else we don't need to add magic to record 0 placeholders. */
2561 S_refcounted_he_value(pTHX_ const struct refcounted_he *he)
2566 PERL_ARGS_ASSERT_REFCOUNTED_HE_VALUE;
2568 switch(he->refcounted_he_data[0] & HVrhek_typemask) {
2573 value = &PL_sv_placeholder;
2576 value = newSViv(he->refcounted_he_val.refcounted_he_u_iv);
2579 value = newSVuv(he->refcounted_he_val.refcounted_he_u_uv);
2582 case HVrhek_PV_UTF8:
2583 /* Create a string SV that directly points to the bytes in our
2585 value = newSV_type(SVt_PV);
2586 SvPV_set(value, (char *) he->refcounted_he_data + 1);
2587 SvCUR_set(value, he->refcounted_he_val.refcounted_he_u_len);
2588 /* This stops anything trying to free it */
2589 SvLEN_set(value, 0);
2591 SvREADONLY_on(value);
2592 if ((he->refcounted_he_data[0] & HVrhek_typemask) == HVrhek_PV_UTF8)
2596 Perl_croak(aTHX_ "panic: refcounted_he_value bad flags %x",
2597 he->refcounted_he_data[0]);
2603 =for apidoc refcounted_he_chain_2hv
2605 Generates and returns a C<HV *> by walking up the tree starting at the passed
2606 in C<struct refcounted_he *>.
2611 Perl_refcounted_he_chain_2hv(pTHX_ const struct refcounted_he *chain)
2615 U32 placeholders = 0;
2616 /* We could chase the chain once to get an idea of the number of keys,
2617 and call ksplit. But for now we'll make a potentially inefficient
2618 hash with only 8 entries in its array. */
2619 const U32 max = HvMAX(hv);
2623 Newxz(array, PERL_HV_ARRAY_ALLOC_BYTES(max + 1), char);
2624 HvARRAY(hv) = (HE**)array;
2629 U32 hash = chain->refcounted_he_hash;
2631 U32 hash = HEK_HASH(chain->refcounted_he_hek);
2633 HE **oentry = &((HvARRAY(hv))[hash & max]);
2634 HE *entry = *oentry;
2637 for (; entry; entry = HeNEXT(entry)) {
2638 if (HeHASH(entry) == hash) {
2639 /* We might have a duplicate key here. If so, entry is older
2640 than the key we've already put in the hash, so if they are
2641 the same, skip adding entry. */
2643 const STRLEN klen = HeKLEN(entry);
2644 const char *const key = HeKEY(entry);
2645 if (klen == chain->refcounted_he_keylen
2646 && (!!HeKUTF8(entry)
2647 == !!(chain->refcounted_he_data[0] & HVhek_UTF8))
2648 && memEQ(key, REF_HE_KEY(chain), klen))
2651 if (HeKEY_hek(entry) == chain->refcounted_he_hek)
2653 if (HeKLEN(entry) == HEK_LEN(chain->refcounted_he_hek)
2654 && HeKUTF8(entry) == HEK_UTF8(chain->refcounted_he_hek)
2655 && memEQ(HeKEY(entry), HEK_KEY(chain->refcounted_he_hek),
2666 = share_hek_flags(REF_HE_KEY(chain),
2667 chain->refcounted_he_keylen,
2668 chain->refcounted_he_hash,
2669 (chain->refcounted_he_data[0]
2670 & (HVhek_UTF8|HVhek_WASUTF8)));
2672 HeKEY_hek(entry) = share_hek_hek(chain->refcounted_he_hek);
2674 value = refcounted_he_value(chain);
2675 if (value == &PL_sv_placeholder)
2677 HeVAL(entry) = value;
2679 /* Link it into the chain. */
2680 HeNEXT(entry) = *oentry;
2681 if (!HeNEXT(entry)) {
2682 /* initial entry. */
2690 chain = chain->refcounted_he_next;
2694 clear_placeholders(hv, placeholders);
2695 HvTOTALKEYS(hv) -= placeholders;
2698 /* We could check in the loop to see if we encounter any keys with key
2699 flags, but it's probably not worth it, as this per-hash flag is only
2700 really meant as an optimisation for things like Storable. */
2702 DEBUG_A(Perl_hv_assert(aTHX_ hv));
2708 Perl_refcounted_he_fetch(pTHX_ const struct refcounted_he *chain, SV *keysv,
2709 const char *key, STRLEN klen, int flags, U32 hash)
2712 /* Just to be awkward, if you're using this interface the UTF-8-or-not-ness
2713 of your key has to exactly match that which is stored. */
2714 SV *value = &PL_sv_placeholder;
2717 /* No point in doing any of this if there's nothing to find. */
2721 if (flags & HVhek_FREEKEY)
2723 key = SvPV_const(keysv, klen);
2725 is_utf8 = (SvUTF8(keysv) != 0);
2727 is_utf8 = ((flags & HVhek_UTF8) ? TRUE : FALSE);
2731 if (keysv && (SvIsCOW_shared_hash(keysv))) {
2732 hash = SvSHARED_HASH(keysv);
2734 PERL_HASH(hash, key, klen);
2738 for (; chain; chain = chain->refcounted_he_next) {
2740 if (hash != chain->refcounted_he_hash)
2742 if (klen != chain->refcounted_he_keylen)
2744 if (memNE(REF_HE_KEY(chain),key,klen))
2746 if (!!is_utf8 != !!(chain->refcounted_he_data[0] & HVhek_UTF8))
2749 if (hash != HEK_HASH(chain->refcounted_he_hek))
2751 if (klen != (STRLEN)HEK_LEN(chain->refcounted_he_hek))
2753 if (memNE(HEK_KEY(chain->refcounted_he_hek),key,klen))
2755 if (!!is_utf8 != !!HEK_UTF8(chain->refcounted_he_hek))
2759 value = sv_2mortal(refcounted_he_value(chain));
2764 if (flags & HVhek_FREEKEY)
2771 =for apidoc refcounted_he_new
2773 Creates a new C<struct refcounted_he>. As S<key> is copied, and value is
2774 stored in a compact form, all references remain the property of the caller.
2775 The C<struct refcounted_he> is returned with a reference count of 1.
2780 struct refcounted_he *
2781 Perl_refcounted_he_new(pTHX_ struct refcounted_he *const parent,
2782 SV *const key, SV *const value) {
2785 const char *key_p = SvPV_const(key, key_len);
2786 STRLEN value_len = 0;
2787 const char *value_p = NULL;
2790 bool is_utf8 = SvUTF8(key) ? TRUE : FALSE;
2793 value_type = HVrhek_PV;
2794 } else if (SvIOK(value)) {
2795 value_type = SvUOK((const SV *)value) ? HVrhek_UV : HVrhek_IV;
2796 } else if (value == &PL_sv_placeholder) {
2797 value_type = HVrhek_delete;
2798 } else if (!SvOK(value)) {
2799 value_type = HVrhek_undef;
2801 value_type = HVrhek_PV;
2804 if (value_type == HVrhek_PV) {
2805 /* Do it this way so that the SvUTF8() test is after the SvPV, in case
2806 the value is overloaded, and doesn't yet have the UTF-8flag set. */
2807 value_p = SvPV_const(value, value_len);
2809 value_type = HVrhek_PV_UTF8;
2814 /* Hash keys are always stored normalised to (yes) ISO-8859-1.
2815 As we're going to be building hash keys from this value in future,
2816 normalise it now. */
2817 key_p = (char*)bytes_from_utf8((const U8*)key_p, &key_len, &is_utf8);
2818 flags |= is_utf8 ? HVhek_UTF8 : HVhek_WASUTF8;
2821 return refcounted_he_new_common(parent, key_p, key_len, flags, value_type,
2822 ((value_type == HVrhek_PV
2823 || value_type == HVrhek_PV_UTF8) ?
2824 (void *)value_p : (void *)value),
2828 static struct refcounted_he *
2829 S_refcounted_he_new_common(pTHX_ struct refcounted_he *const parent,
2830 const char *const key_p, const STRLEN key_len,
2831 const char flags, char value_type,
2832 const void *value, const STRLEN value_len) {
2834 struct refcounted_he *he;
2836 const bool is_pv = value_type == HVrhek_PV || value_type == HVrhek_PV_UTF8;
2837 STRLEN key_offset = is_pv ? value_len + 2 : 1;
2839 PERL_ARGS_ASSERT_REFCOUNTED_HE_NEW_COMMON;
2842 he = (struct refcounted_he*)
2843 PerlMemShared_malloc(sizeof(struct refcounted_he) - 1
2847 he = (struct refcounted_he*)
2848 PerlMemShared_malloc(sizeof(struct refcounted_he) - 1
2852 he->refcounted_he_next = parent;
2855 Copy((char *)value, he->refcounted_he_data + 1, value_len + 1, char);
2856 he->refcounted_he_val.refcounted_he_u_len = value_len;
2857 } else if (value_type == HVrhek_IV) {
2858 he->refcounted_he_val.refcounted_he_u_iv = SvIVX((const SV *)value);
2859 } else if (value_type == HVrhek_UV) {
2860 he->refcounted_he_val.refcounted_he_u_uv = SvUVX((const SV *)value);
2863 PERL_HASH(hash, key_p, key_len);
2866 he->refcounted_he_hash = hash;
2867 he->refcounted_he_keylen = key_len;
2868 Copy(key_p, he->refcounted_he_data + key_offset, key_len, char);
2870 he->refcounted_he_hek = share_hek_flags(key_p, key_len, hash, flags);
2873 if (flags & HVhek_WASUTF8) {
2874 /* If it was downgraded from UTF-8, then the pointer returned from
2875 bytes_from_utf8 is an allocated pointer that we must free. */
2879 he->refcounted_he_data[0] = flags;
2880 he->refcounted_he_refcnt = 1;
2886 =for apidoc refcounted_he_free
2888 Decrements the reference count of the passed in C<struct refcounted_he *>
2889 by one. If the reference count reaches zero the structure's memory is freed,
2890 and C<refcounted_he_free> iterates onto the parent node.
2896 Perl_refcounted_he_free(pTHX_ struct refcounted_he *he) {
2898 PERL_UNUSED_CONTEXT;
2901 struct refcounted_he *copy;
2905 new_count = --he->refcounted_he_refcnt;
2906 HINTS_REFCNT_UNLOCK;
2912 #ifndef USE_ITHREADS
2913 unshare_hek_or_pvn (he->refcounted_he_hek, 0, 0, 0);
2916 he = he->refcounted_he_next;
2917 PerlMemShared_free(copy);
2922 Perl_fetch_cop_label(pTHX_ struct refcounted_he *const chain, STRLEN *len,
2927 if (chain->refcounted_he_keylen != 1)
2929 if (*REF_HE_KEY(chain) != ':')
2932 if ((STRLEN)HEK_LEN(chain->refcounted_he_hek) != 1)
2934 if (*HEK_KEY(chain->refcounted_he_hek) != ':')
2937 /* Stop anyone trying to really mess us up by adding their own value for
2939 if ((chain->refcounted_he_data[0] & HVrhek_typemask) != HVrhek_PV
2940 && (chain->refcounted_he_data[0] & HVrhek_typemask) != HVrhek_PV_UTF8)
2944 *len = chain->refcounted_he_val.refcounted_he_u_len;
2946 *flags = ((chain->refcounted_he_data[0] & HVrhek_typemask)
2947 == HVrhek_PV_UTF8) ? SVf_UTF8 : 0;
2949 return chain->refcounted_he_data + 1;
2952 /* As newSTATEOP currently gets passed plain char* labels, we will only provide
2953 that interface. Once it works out how to pass in length and UTF-8 ness, this
2954 function will need superseding. */
2955 struct refcounted_he *
2956 Perl_store_cop_label(pTHX_ struct refcounted_he *const chain, const char *label)
2958 PERL_ARGS_ASSERT_STORE_COP_LABEL;
2960 return refcounted_he_new_common(chain, ":", 1, HVrhek_PV, HVrhek_PV,
2961 label, strlen(label));
2965 =for apidoc hv_assert
2967 Check that a hash is in an internally consistent state.
2975 Perl_hv_assert(pTHX_ HV *hv)
2980 int placeholders = 0;
2983 const I32 riter = HvRITER_get(hv);
2984 HE *eiter = HvEITER_get(hv);
2986 PERL_ARGS_ASSERT_HV_ASSERT;
2988 (void)hv_iterinit(hv);
2990 while ((entry = hv_iternext_flags(hv, HV_ITERNEXT_WANTPLACEHOLDERS))) {
2991 /* sanity check the values */
2992 if (HeVAL(entry) == &PL_sv_placeholder)
2996 /* sanity check the keys */
2997 if (HeSVKEY(entry)) {
2998 NOOP; /* Don't know what to check on SV keys. */
2999 } else if (HeKUTF8(entry)) {
3001 if (HeKWASUTF8(entry)) {
3002 PerlIO_printf(Perl_debug_log,
3003 "hash key has both WASUTF8 and UTF8: '%.*s'\n",
3004 (int) HeKLEN(entry), HeKEY(entry));
3007 } else if (HeKWASUTF8(entry))
3010 if (!SvTIED_mg((const SV *)hv, PERL_MAGIC_tied)) {
3011 static const char bad_count[] = "Count %d %s(s), but hash reports %d\n";
3012 const int nhashkeys = HvUSEDKEYS(hv);
3013 const int nhashplaceholders = HvPLACEHOLDERS_get(hv);
3015 if (nhashkeys != real) {
3016 PerlIO_printf(Perl_debug_log, bad_count, real, "keys", nhashkeys );
3019 if (nhashplaceholders != placeholders) {
3020 PerlIO_printf(Perl_debug_log, bad_count, placeholders, "placeholder", nhashplaceholders );
3024 if (withflags && ! HvHASKFLAGS(hv)) {
3025 PerlIO_printf(Perl_debug_log,
3026 "Hash has HASKFLAGS off but I count %d key(s) with flags\n",
3031 sv_dump(MUTABLE_SV(hv));
3033 HvRITER_set(hv, riter); /* Restore hash iterator state */
3034 HvEITER_set(hv, eiter);
3041 * c-indentation-style: bsd
3043 * indent-tabs-mode: t
3046 * ex: set ts=8 sts=4 sw=4 noet: