3 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
4 * 2000, 2001, 2002, 2003, 2004, 2005, 2006, 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 of all that I have seen." --Bilbo
16 =head1 Hash Manipulation Functions
18 A HV structure represents a Perl hash. It consists mainly of an array
19 of pointers, each of which points to a linked list of HE structures. The
20 array is indexed by the hash function of the key, so each linked list
21 represents all the hash entries with the same hash value. Each HE contains
22 a pointer to the actual value, plus a pointer to a HEK structure which
23 holds the key and hash value.
31 #define PERL_HASH_INTERNAL_ACCESS
34 #define HV_MAX_LENGTH_BEFORE_SPLIT 14
36 static const char S_strtab_error[]
37 = "Cannot modify shared string table in hv_%s";
46 he = (HE*) Perl_get_arena(aTHX_ PERL_ARENA_SIZE);
48 heend = &he[PERL_ARENA_SIZE / sizeof(HE) - 1];
49 PL_body_roots[HE_SVSLOT] = ++he;
51 HeNEXT(he) = (HE*)(he + 1);
59 #define new_HE() (HE*)safemalloc(sizeof(HE))
60 #define del_HE(p) safefree((char*)p)
69 void ** const root = &PL_body_roots[HE_SVSLOT];
80 #define new_HE() new_he()
84 HeNEXT(p) = (HE*)(PL_body_roots[HE_SVSLOT]); \
85 PL_body_roots[HE_SVSLOT] = p; \
94 S_save_hek_flags(const char *str, I32 len, U32 hash, int flags)
96 const int flags_masked = flags & HVhek_MASK;
100 Newx(k, HEK_BASESIZE + len + 2, char);
102 Copy(str, HEK_KEY(hek), len, char);
103 HEK_KEY(hek)[len] = 0;
105 HEK_HASH(hek) = hash;
106 HEK_FLAGS(hek) = (unsigned char)flags_masked;
108 if (flags & HVhek_FREEKEY)
113 /* free the pool of temporary HE/HEK pairs returned by hv_fetch_ent
117 Perl_free_tied_hv_pool(pTHX)
120 HE *he = PL_hv_fetch_ent_mh;
123 Safefree(HeKEY_hek(he));
127 PL_hv_fetch_ent_mh = Nullhe;
130 #if defined(USE_ITHREADS)
132 Perl_hek_dup(pTHX_ HEK *source, CLONE_PARAMS* param)
134 HEK *shared = (HEK*)ptr_table_fetch(PL_ptr_table, source);
136 PERL_UNUSED_ARG(param);
139 /* We already shared this hash key. */
140 (void)share_hek_hek(shared);
144 = share_hek_flags(HEK_KEY(source), HEK_LEN(source),
145 HEK_HASH(source), HEK_FLAGS(source));
146 ptr_table_store(PL_ptr_table, source, shared);
152 Perl_he_dup(pTHX_ const HE *e, bool shared, CLONE_PARAMS* param)
158 /* look for it in the table first */
159 ret = (HE*)ptr_table_fetch(PL_ptr_table, e);
163 /* create anew and remember what it is */
165 ptr_table_store(PL_ptr_table, e, ret);
167 HeNEXT(ret) = he_dup(HeNEXT(e),shared, param);
168 if (HeKLEN(e) == HEf_SVKEY) {
170 Newx(k, HEK_BASESIZE + sizeof(SV*), char);
171 HeKEY_hek(ret) = (HEK*)k;
172 HeKEY_sv(ret) = SvREFCNT_inc(sv_dup(HeKEY_sv(e), param));
175 /* This is hek_dup inlined, which seems to be important for speed
177 HEK * const source = HeKEY_hek(e);
178 HEK *shared = (HEK*)ptr_table_fetch(PL_ptr_table, source);
181 /* We already shared this hash key. */
182 (void)share_hek_hek(shared);
186 = share_hek_flags(HEK_KEY(source), HEK_LEN(source),
187 HEK_HASH(source), HEK_FLAGS(source));
188 ptr_table_store(PL_ptr_table, source, shared);
190 HeKEY_hek(ret) = shared;
193 HeKEY_hek(ret) = save_hek_flags(HeKEY(e), HeKLEN(e), HeHASH(e),
195 HeVAL(ret) = SvREFCNT_inc(sv_dup(HeVAL(e), param));
198 #endif /* USE_ITHREADS */
201 S_hv_notallowed(pTHX_ int flags, const char *key, I32 klen,
204 SV * const sv = sv_newmortal();
205 if (!(flags & HVhek_FREEKEY)) {
206 sv_setpvn(sv, key, klen);
209 /* Need to free saved eventually assign to mortal SV */
210 /* XXX is this line an error ???: SV *sv = sv_newmortal(); */
211 sv_usepvn(sv, (char *) key, klen);
213 if (flags & HVhek_UTF8) {
216 Perl_croak(aTHX_ msg, sv);
219 /* (klen == HEf_SVKEY) is special for MAGICAL hv entries, meaning key slot
222 #define HV_FETCH_ISSTORE 0x01
223 #define HV_FETCH_ISEXISTS 0x02
224 #define HV_FETCH_LVALUE 0x04
225 #define HV_FETCH_JUST_SV 0x08
230 Stores an SV in a hash. The hash key is specified as C<key> and C<klen> is
231 the length of the key. The C<hash> parameter is the precomputed hash
232 value; if it is zero then Perl will compute it. The return value will be
233 NULL if the operation failed or if the value did not need to be actually
234 stored within the hash (as in the case of tied hashes). Otherwise it can
235 be dereferenced to get the original C<SV*>. Note that the caller is
236 responsible for suitably incrementing the reference count of C<val> before
237 the call, and decrementing it if the function returned NULL. Effectively
238 a successful hv_store takes ownership of one reference to C<val>. This is
239 usually what you want; a newly created SV has a reference count of one, so
240 if all your code does is create SVs then store them in a hash, hv_store
241 will own the only reference to the new SV, and your code doesn't need to do
242 anything further to tidy up. hv_store is not implemented as a call to
243 hv_store_ent, and does not create a temporary SV for the key, so if your
244 key data is not already in SV form then use hv_store in preference to
247 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
248 information on how to use this function on tied hashes.
254 Perl_hv_store(pTHX_ HV *hv, const char *key, I32 klen_i32, SV *val, U32 hash)
267 hek = hv_fetch_common (hv, NULL, key, klen, flags,
268 (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), val, hash);
269 return hek ? &HeVAL(hek) : NULL;
272 /* XXX This looks like an ideal candidate to inline */
274 Perl_hv_store_flags(pTHX_ HV *hv, const char *key, I32 klen, SV *val,
275 register U32 hash, int flags)
277 HE * const hek = hv_fetch_common (hv, NULL, key, klen, flags,
278 (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), val, hash);
279 return hek ? &HeVAL(hek) : NULL;
283 =for apidoc hv_store_ent
285 Stores C<val> in a hash. The hash key is specified as C<key>. The C<hash>
286 parameter is the precomputed hash value; if it is zero then Perl will
287 compute it. The return value is the new hash entry so created. It will be
288 NULL if the operation failed or if the value did not need to be actually
289 stored within the hash (as in the case of tied hashes). Otherwise the
290 contents of the return value can be accessed using the C<He?> macros
291 described here. Note that the caller is responsible for suitably
292 incrementing the reference count of C<val> before the call, and
293 decrementing it if the function returned NULL. Effectively a successful
294 hv_store_ent takes ownership of one reference to C<val>. This is
295 usually what you want; a newly created SV has a reference count of one, so
296 if all your code does is create SVs then store them in a hash, hv_store
297 will own the only reference to the new SV, and your code doesn't need to do
298 anything further to tidy up. Note that hv_store_ent only reads the C<key>;
299 unlike C<val> it does not take ownership of it, so maintaining the correct
300 reference count on C<key> is entirely the caller's responsibility. hv_store
301 is not implemented as a call to hv_store_ent, and does not create a temporary
302 SV for the key, so if your key data is not already in SV form then use
303 hv_store in preference to hv_store_ent.
305 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
306 information on how to use this function on tied hashes.
311 /* XXX This looks like an ideal candidate to inline */
313 Perl_hv_store_ent(pTHX_ HV *hv, SV *keysv, SV *val, U32 hash)
315 return hv_fetch_common(hv, keysv, NULL, 0, 0, HV_FETCH_ISSTORE, val, hash);
319 =for apidoc hv_exists
321 Returns a boolean indicating whether the specified hash key exists. The
322 C<klen> is the length of the key.
328 Perl_hv_exists(pTHX_ HV *hv, const char *key, I32 klen_i32)
340 return hv_fetch_common(hv, NULL, key, klen, flags, HV_FETCH_ISEXISTS, 0, 0)
347 Returns the SV which corresponds to the specified key in the hash. The
348 C<klen> is the length of the key. If C<lval> is set then the fetch will be
349 part of a store. Check that the return value is non-null before
350 dereferencing it to an C<SV*>.
352 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
353 information on how to use this function on tied hashes.
359 Perl_hv_fetch(pTHX_ HV *hv, const char *key, I32 klen_i32, I32 lval)
372 hek = hv_fetch_common (hv, NULL, key, klen, flags,
373 lval ? (HV_FETCH_JUST_SV | HV_FETCH_LVALUE) : HV_FETCH_JUST_SV,
375 return hek ? &HeVAL(hek) : NULL;
379 =for apidoc hv_exists_ent
381 Returns a boolean indicating whether the specified hash key exists. C<hash>
382 can be a valid precomputed hash value, or 0 to ask for it to be
388 /* XXX This looks like an ideal candidate to inline */
390 Perl_hv_exists_ent(pTHX_ HV *hv, SV *keysv, U32 hash)
392 return hv_fetch_common(hv, keysv, NULL, 0, 0, HV_FETCH_ISEXISTS, 0, hash)
396 /* returns an HE * structure with the all fields set */
397 /* note that hent_val will be a mortal sv for MAGICAL hashes */
399 =for apidoc hv_fetch_ent
401 Returns the hash entry which corresponds to the specified key in the hash.
402 C<hash> must be a valid precomputed hash number for the given C<key>, or 0
403 if you want the function to compute it. IF C<lval> is set then the fetch
404 will be part of a store. Make sure the return value is non-null before
405 accessing it. The return value when C<tb> is a tied hash is a pointer to a
406 static location, so be sure to make a copy of the structure if you need to
409 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
410 information on how to use this function on tied hashes.
416 Perl_hv_fetch_ent(pTHX_ HV *hv, SV *keysv, I32 lval, register U32 hash)
418 return hv_fetch_common(hv, keysv, NULL, 0, 0,
419 (lval ? HV_FETCH_LVALUE : 0), NULL, hash);
423 S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
424 int flags, int action, SV *val, register U32 hash)
438 if (flags & HVhek_FREEKEY)
440 key = SvPV_const(keysv, klen);
442 is_utf8 = (SvUTF8(keysv) != 0);
444 is_utf8 = ((flags & HVhek_UTF8) ? TRUE : FALSE);
447 xhv = (XPVHV*)SvANY(hv);
449 if (SvRMAGICAL(hv) && !(action & (HV_FETCH_ISSTORE|HV_FETCH_ISEXISTS))) {
450 if (mg_find((SV*)hv, PERL_MAGIC_tied) || SvGMAGICAL((SV*)hv)) {
453 /* XXX should be able to skimp on the HE/HEK here when
454 HV_FETCH_JUST_SV is true. */
457 keysv = newSVpvn(key, klen);
462 keysv = newSVsv(keysv);
464 mg_copy((SV*)hv, sv, (char *)keysv, HEf_SVKEY);
466 /* grab a fake HE/HEK pair from the pool or make a new one */
467 entry = PL_hv_fetch_ent_mh;
469 PL_hv_fetch_ent_mh = HeNEXT(entry);
473 Newx(k, HEK_BASESIZE + sizeof(SV*), char);
474 HeKEY_hek(entry) = (HEK*)k;
476 HeNEXT(entry) = Nullhe;
477 HeSVKEY_set(entry, keysv);
479 sv_upgrade(sv, SVt_PVLV);
481 /* so we can free entry when freeing sv */
482 LvTARG(sv) = (SV*)entry;
484 /* XXX remove at some point? */
485 if (flags & HVhek_FREEKEY)
490 #ifdef ENV_IS_CASELESS
491 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
493 for (i = 0; i < klen; ++i)
494 if (isLOWER(key[i])) {
495 /* Would be nice if we had a routine to do the
496 copy and upercase in a single pass through. */
497 const char * const nkey = strupr(savepvn(key,klen));
498 /* Note that this fetch is for nkey (the uppercased
499 key) whereas the store is for key (the original) */
500 entry = hv_fetch_common(hv, NULL, nkey, klen,
501 HVhek_FREEKEY, /* free nkey */
502 0 /* non-LVAL fetch */,
504 0 /* compute hash */);
505 if (!entry && (action & HV_FETCH_LVALUE)) {
506 /* This call will free key if necessary.
507 Do it this way to encourage compiler to tail
509 entry = hv_fetch_common(hv, keysv, key, klen,
510 flags, HV_FETCH_ISSTORE,
513 if (flags & HVhek_FREEKEY)
521 else if (SvRMAGICAL(hv) && (action & HV_FETCH_ISEXISTS)) {
522 if (mg_find((SV*)hv, PERL_MAGIC_tied) || SvGMAGICAL((SV*)hv)) {
523 /* I don't understand why hv_exists_ent has svret and sv,
524 whereas hv_exists only had one. */
525 SV * const svret = sv_newmortal();
528 if (keysv || is_utf8) {
530 keysv = newSVpvn(key, klen);
533 keysv = newSVsv(keysv);
535 mg_copy((SV*)hv, sv, (char *)sv_2mortal(keysv), HEf_SVKEY);
537 mg_copy((SV*)hv, sv, key, klen);
539 if (flags & HVhek_FREEKEY)
541 magic_existspack(svret, mg_find(sv, PERL_MAGIC_tiedelem));
542 /* This cast somewhat evil, but I'm merely using NULL/
543 not NULL to return the boolean exists.
544 And I know hv is not NULL. */
545 return SvTRUE(svret) ? (HE *)hv : NULL;
547 #ifdef ENV_IS_CASELESS
548 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
549 /* XXX This code isn't UTF8 clean. */
550 char * const keysave = (char * const)key;
551 /* Will need to free this, so set FREEKEY flag. */
552 key = savepvn(key,klen);
553 key = (const char*)strupr((char*)key);
558 if (flags & HVhek_FREEKEY) {
561 flags |= HVhek_FREEKEY;
565 else if (action & HV_FETCH_ISSTORE) {
568 hv_magic_check (hv, &needs_copy, &needs_store);
570 const bool save_taint = PL_tainted;
571 if (keysv || is_utf8) {
573 keysv = newSVpvn(key, klen);
577 PL_tainted = SvTAINTED(keysv);
578 keysv = sv_2mortal(newSVsv(keysv));
579 mg_copy((SV*)hv, val, (char*)keysv, HEf_SVKEY);
581 mg_copy((SV*)hv, val, key, klen);
584 TAINT_IF(save_taint);
585 if (!HvARRAY(hv) && !needs_store) {
586 if (flags & HVhek_FREEKEY)
590 #ifdef ENV_IS_CASELESS
591 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
592 /* XXX This code isn't UTF8 clean. */
593 const char *keysave = key;
594 /* Will need to free this, so set FREEKEY flag. */
595 key = savepvn(key,klen);
596 key = (const char*)strupr((char*)key);
601 if (flags & HVhek_FREEKEY) {
604 flags |= HVhek_FREEKEY;
612 if ((action & (HV_FETCH_LVALUE | HV_FETCH_ISSTORE))
613 #ifdef DYNAMIC_ENV_FETCH /* if it's an %ENV lookup, we may get it on the fly */
614 || (SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env))
619 PERL_HV_ARRAY_ALLOC_BYTES(xhv->xhv_max+1 /* HvMAX(hv)+1 */),
621 HvARRAY(hv) = (HE**)array;
623 #ifdef DYNAMIC_ENV_FETCH
624 else if (action & HV_FETCH_ISEXISTS) {
625 /* for an %ENV exists, if we do an insert it's by a recursive
626 store call, so avoid creating HvARRAY(hv) right now. */
630 /* XXX remove at some point? */
631 if (flags & HVhek_FREEKEY)
639 char * const keysave = (char *)key;
640 key = (char*)bytes_from_utf8((U8*)key, &klen, &is_utf8);
644 flags &= ~HVhek_UTF8;
645 if (key != keysave) {
646 if (flags & HVhek_FREEKEY)
648 flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
653 PERL_HASH_INTERNAL(hash, key, klen);
654 /* We don't have a pointer to the hv, so we have to replicate the
655 flag into every HEK, so that hv_iterkeysv can see it. */
656 /* And yes, you do need this even though you are not "storing" because
657 you can flip the flags below if doing an lval lookup. (And that
658 was put in to give the semantics Andreas was expecting.) */
659 flags |= HVhek_REHASH;
661 if (keysv && (SvIsCOW_shared_hash(keysv))) {
662 hash = SvSHARED_HASH(keysv);
664 PERL_HASH(hash, key, klen);
668 masked_flags = (flags & HVhek_MASK);
670 #ifdef DYNAMIC_ENV_FETCH
671 if (!HvARRAY(hv)) entry = Null(HE*);
675 entry = (HvARRAY(hv))[hash & (I32) HvMAX(hv)];
677 for (; entry; entry = HeNEXT(entry)) {
678 if (HeHASH(entry) != hash) /* strings can't be equal */
680 if (HeKLEN(entry) != (I32)klen)
682 if (HeKEY(entry) != key && memNE(HeKEY(entry),key,klen)) /* is this it? */
684 if ((HeKFLAGS(entry) ^ masked_flags) & HVhek_UTF8)
687 if (action & (HV_FETCH_LVALUE|HV_FETCH_ISSTORE)) {
688 if (HeKFLAGS(entry) != masked_flags) {
689 /* We match if HVhek_UTF8 bit in our flags and hash key's
690 match. But if entry was set previously with HVhek_WASUTF8
691 and key now doesn't (or vice versa) then we should change
692 the key's flag, as this is assignment. */
693 if (HvSHAREKEYS(hv)) {
694 /* Need to swap the key we have for a key with the flags we
695 need. As keys are shared we can't just write to the
696 flag, so we share the new one, unshare the old one. */
697 HEK * const new_hek = share_hek_flags(key, klen, hash,
699 unshare_hek (HeKEY_hek(entry));
700 HeKEY_hek(entry) = new_hek;
702 else if (hv == PL_strtab) {
703 /* PL_strtab is usually the only hash without HvSHAREKEYS,
704 so putting this test here is cheap */
705 if (flags & HVhek_FREEKEY)
707 Perl_croak(aTHX_ S_strtab_error,
708 action & HV_FETCH_LVALUE ? "fetch" : "store");
711 HeKFLAGS(entry) = masked_flags;
712 if (masked_flags & HVhek_ENABLEHVKFLAGS)
715 if (HeVAL(entry) == &PL_sv_placeholder) {
716 /* yes, can store into placeholder slot */
717 if (action & HV_FETCH_LVALUE) {
719 /* This preserves behaviour with the old hv_fetch
720 implementation which at this point would bail out
721 with a break; (at "if we find a placeholder, we
722 pretend we haven't found anything")
724 That break mean that if a placeholder were found, it
725 caused a call into hv_store, which in turn would
726 check magic, and if there is no magic end up pretty
727 much back at this point (in hv_store's code). */
730 /* LVAL fetch which actaully needs a store. */
732 HvPLACEHOLDERS(hv)--;
735 if (val != &PL_sv_placeholder)
736 HvPLACEHOLDERS(hv)--;
739 } else if (action & HV_FETCH_ISSTORE) {
740 SvREFCNT_dec(HeVAL(entry));
743 } else if (HeVAL(entry) == &PL_sv_placeholder) {
744 /* if we find a placeholder, we pretend we haven't found
748 if (flags & HVhek_FREEKEY)
752 #ifdef DYNAMIC_ENV_FETCH /* %ENV lookup? If so, try to fetch the value now */
753 if (!(action & HV_FETCH_ISSTORE)
754 && SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env)) {
756 const char * const env = PerlEnv_ENVgetenv_len(key,&len);
758 sv = newSVpvn(env,len);
760 return hv_fetch_common(hv,keysv,key,klen,flags,HV_FETCH_ISSTORE,sv,
766 if (!entry && SvREADONLY(hv) && !(action & HV_FETCH_ISEXISTS)) {
767 hv_notallowed(flags, key, klen,
768 "Attempt to access disallowed key '%"SVf"' in"
769 " a restricted hash");
771 if (!(action & (HV_FETCH_LVALUE|HV_FETCH_ISSTORE))) {
772 /* Not doing some form of store, so return failure. */
773 if (flags & HVhek_FREEKEY)
777 if (action & HV_FETCH_LVALUE) {
780 /* At this point the old hv_fetch code would call to hv_store,
781 which in turn might do some tied magic. So we need to make that
782 magic check happen. */
783 /* gonna assign to this, so it better be there */
784 return hv_fetch_common(hv, keysv, key, klen, flags,
785 HV_FETCH_ISSTORE, val, hash);
786 /* XXX Surely that could leak if the fetch-was-store fails?
787 Just like the hv_fetch. */
791 /* Welcome to hv_store... */
794 /* Not sure if we can get here. I think the only case of oentry being
795 NULL is for %ENV with dynamic env fetch. But that should disappear
796 with magic in the previous code. */
799 PERL_HV_ARRAY_ALLOC_BYTES(xhv->xhv_max+1 /* HvMAX(hv)+1 */),
801 HvARRAY(hv) = (HE**)array;
804 oentry = &(HvARRAY(hv))[hash & (I32) xhv->xhv_max];
807 /* share_hek_flags will do the free for us. This might be considered
810 HeKEY_hek(entry) = share_hek_flags(key, klen, hash, flags);
811 else if (hv == PL_strtab) {
812 /* PL_strtab is usually the only hash without HvSHAREKEYS, so putting
813 this test here is cheap */
814 if (flags & HVhek_FREEKEY)
816 Perl_croak(aTHX_ S_strtab_error,
817 action & HV_FETCH_LVALUE ? "fetch" : "store");
819 else /* gotta do the real thing */
820 HeKEY_hek(entry) = save_hek_flags(key, klen, hash, flags);
822 HeNEXT(entry) = *oentry;
825 if (val == &PL_sv_placeholder)
826 HvPLACEHOLDERS(hv)++;
827 if (masked_flags & HVhek_ENABLEHVKFLAGS)
831 const HE *counter = HeNEXT(entry);
833 xhv->xhv_keys++; /* HvKEYS(hv)++ */
834 if (!counter) { /* initial entry? */
835 xhv->xhv_fill++; /* HvFILL(hv)++ */
836 } else if (xhv->xhv_keys > (IV)xhv->xhv_max) {
838 } else if(!HvREHASH(hv)) {
841 while ((counter = HeNEXT(counter)))
844 if (n_links > HV_MAX_LENGTH_BEFORE_SPLIT) {
845 /* Use only the old HvKEYS(hv) > HvMAX(hv) condition to limit
846 bucket splits on a rehashed hash, as we're not going to
847 split it again, and if someone is lucky (evil) enough to
848 get all the keys in one list they could exhaust our memory
849 as we repeatedly double the number of buckets on every
850 entry. Linear search feels a less worse thing to do. */
860 S_hv_magic_check(HV *hv, bool *needs_copy, bool *needs_store)
862 const MAGIC *mg = SvMAGIC(hv);
866 if (isUPPER(mg->mg_type)) {
868 if (mg->mg_type == PERL_MAGIC_tied) {
869 *needs_store = FALSE;
870 return; /* We've set all there is to set. */
873 mg = mg->mg_moremagic;
878 =for apidoc hv_scalar
880 Evaluates the hash in scalar context and returns the result. Handles magic when the hash is tied.
886 Perl_hv_scalar(pTHX_ HV *hv)
890 if (SvRMAGICAL(hv)) {
891 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_tied);
893 return magic_scalarpack(hv, mg);
898 Perl_sv_setpvf(aTHX_ sv, "%ld/%ld",
899 (long)HvFILL(hv), (long)HvMAX(hv) + 1);
907 =for apidoc hv_delete
909 Deletes a key/value pair in the hash. The value SV is removed from the
910 hash and returned to the caller. The C<klen> is the length of the key.
911 The C<flags> value will normally be zero; if set to G_DISCARD then NULL
918 Perl_hv_delete(pTHX_ HV *hv, const char *key, I32 klen_i32, I32 flags)
925 k_flags = HVhek_UTF8;
930 return hv_delete_common(hv, NULL, key, klen, k_flags, flags, 0);
934 =for apidoc hv_delete_ent
936 Deletes a key/value pair in the hash. The value SV is removed from the
937 hash and returned to the caller. The C<flags> value will normally be zero;
938 if set to G_DISCARD then NULL will be returned. C<hash> can be a valid
939 precomputed hash value, or 0 to ask for it to be computed.
944 /* XXX This looks like an ideal candidate to inline */
946 Perl_hv_delete_ent(pTHX_ HV *hv, SV *keysv, I32 flags, U32 hash)
948 return hv_delete_common(hv, keysv, NULL, 0, 0, flags, hash);
952 S_hv_delete_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
953 int k_flags, I32 d_flags, U32 hash)
958 register HE **oentry;
959 HE *const *first_entry;
967 if (k_flags & HVhek_FREEKEY)
969 key = SvPV_const(keysv, klen);
971 is_utf8 = (SvUTF8(keysv) != 0);
973 is_utf8 = ((k_flags & HVhek_UTF8) ? TRUE : FALSE);
976 if (SvRMAGICAL(hv)) {
979 hv_magic_check (hv, &needs_copy, &needs_store);
983 entry = hv_fetch_common(hv, keysv, key, klen,
984 k_flags & ~HVhek_FREEKEY, HV_FETCH_LVALUE,
986 sv = entry ? HeVAL(entry) : NULL;
992 if (mg_find(sv, PERL_MAGIC_tiedelem)) {
993 /* No longer an element */
994 sv_unmagic(sv, PERL_MAGIC_tiedelem);
997 return NULL; /* element cannot be deleted */
999 #ifdef ENV_IS_CASELESS
1000 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
1001 /* XXX This code isn't UTF8 clean. */
1002 keysv = sv_2mortal(newSVpvn(key,klen));
1003 if (k_flags & HVhek_FREEKEY) {
1006 key = strupr(SvPVX(keysv));
1015 xhv = (XPVHV*)SvANY(hv);
1020 const char * const keysave = key;
1021 key = (char*)bytes_from_utf8((U8*)key, &klen, &is_utf8);
1024 k_flags |= HVhek_UTF8;
1026 k_flags &= ~HVhek_UTF8;
1027 if (key != keysave) {
1028 if (k_flags & HVhek_FREEKEY) {
1029 /* This shouldn't happen if our caller does what we expect,
1030 but strictly the API allows it. */
1033 k_flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
1035 HvHASKFLAGS_on((SV*)hv);
1039 PERL_HASH_INTERNAL(hash, key, klen);
1041 if (keysv && (SvIsCOW_shared_hash(keysv))) {
1042 hash = SvSHARED_HASH(keysv);
1044 PERL_HASH(hash, key, klen);
1048 masked_flags = (k_flags & HVhek_MASK);
1050 first_entry = oentry = &(HvARRAY(hv))[hash & (I32) HvMAX(hv)];
1052 for (; entry; oentry = &HeNEXT(entry), entry = *oentry) {
1054 if (HeHASH(entry) != hash) /* strings can't be equal */
1056 if (HeKLEN(entry) != (I32)klen)
1058 if (HeKEY(entry) != key && memNE(HeKEY(entry),key,klen)) /* is this it? */
1060 if ((HeKFLAGS(entry) ^ masked_flags) & HVhek_UTF8)
1063 if (hv == PL_strtab) {
1064 if (k_flags & HVhek_FREEKEY)
1066 Perl_croak(aTHX_ S_strtab_error, "delete");
1069 /* if placeholder is here, it's already been deleted.... */
1070 if (HeVAL(entry) == &PL_sv_placeholder) {
1071 if (k_flags & HVhek_FREEKEY)
1075 if (SvREADONLY(hv) && HeVAL(entry) && SvREADONLY(HeVAL(entry))) {
1076 S_hv_notallowed(aTHX_ k_flags, key, klen,
1077 "Attempt to delete readonly key '%"SVf"' from"
1078 " a restricted hash");
1080 if (k_flags & HVhek_FREEKEY)
1083 if (d_flags & G_DISCARD)
1086 sv = sv_2mortal(HeVAL(entry));
1087 HeVAL(entry) = &PL_sv_placeholder;
1091 * If a restricted hash, rather than really deleting the entry, put
1092 * a placeholder there. This marks the key as being "approved", so
1093 * we can still access via not-really-existing key without raising
1096 if (SvREADONLY(hv)) {
1097 SvREFCNT_dec(HeVAL(entry));
1098 HeVAL(entry) = &PL_sv_placeholder;
1099 /* We'll be saving this slot, so the number of allocated keys
1100 * doesn't go down, but the number placeholders goes up */
1101 HvPLACEHOLDERS(hv)++;
1103 *oentry = HeNEXT(entry);
1105 xhv->xhv_fill--; /* HvFILL(hv)-- */
1107 if (SvOOK(hv) && entry == HvAUX(hv)->xhv_eiter /* HvEITER(hv) */)
1110 hv_free_ent(hv, entry);
1111 xhv->xhv_keys--; /* HvKEYS(hv)-- */
1112 if (xhv->xhv_keys == 0)
1113 HvHASKFLAGS_off(hv);
1117 if (SvREADONLY(hv)) {
1118 S_hv_notallowed(aTHX_ k_flags, key, klen,
1119 "Attempt to delete disallowed key '%"SVf"' from"
1120 " a restricted hash");
1123 if (k_flags & HVhek_FREEKEY)
1129 S_hsplit(pTHX_ HV *hv)
1132 register XPVHV* xhv = (XPVHV*)SvANY(hv);
1133 const I32 oldsize = (I32) xhv->xhv_max+1; /* HvMAX(hv)+1 (sick) */
1134 register I32 newsize = oldsize * 2;
1136 char *a = (char*) HvARRAY(hv);
1138 register HE **oentry;
1139 int longest_chain = 0;
1142 /*PerlIO_printf(PerlIO_stderr(), "hsplit called for %p which had %d\n",
1143 hv, (int) oldsize);*/
1145 if (HvPLACEHOLDERS_get(hv) && !SvREADONLY(hv)) {
1146 /* Can make this clear any placeholders first for non-restricted hashes,
1147 even though Storable rebuilds restricted hashes by putting in all the
1148 placeholders (first) before turning on the readonly flag, because
1149 Storable always pre-splits the hash. */
1150 hv_clear_placeholders(hv);
1154 #if defined(STRANGE_MALLOC) || defined(MYMALLOC)
1155 Renew(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1156 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1162 Copy(&a[oldsize * sizeof(HE*)], &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1165 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1166 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1171 Copy(HvARRAY(hv), a, oldsize * sizeof(HE*), char);
1173 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1175 if (oldsize >= 64) {
1176 offer_nice_chunk(HvARRAY(hv),
1177 PERL_HV_ARRAY_ALLOC_BYTES(oldsize)
1178 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0));
1181 Safefree(HvARRAY(hv));
1185 Zero(&a[oldsize * sizeof(HE*)], (newsize-oldsize) * sizeof(HE*), char); /* zero 2nd half*/
1186 xhv->xhv_max = --newsize; /* HvMAX(hv) = --newsize */
1187 HvARRAY(hv) = (HE**) a;
1190 for (i=0; i<oldsize; i++,aep++) {
1191 int left_length = 0;
1192 int right_length = 0;
1196 if (!*aep) /* non-existent */
1199 for (oentry = aep, entry = *aep; entry; entry = *oentry) {
1200 if ((HeHASH(entry) & newsize) != (U32)i) {
1201 *oentry = HeNEXT(entry);
1202 HeNEXT(entry) = *bep;
1204 xhv->xhv_fill++; /* HvFILL(hv)++ */
1210 oentry = &HeNEXT(entry);
1214 if (!*aep) /* everything moved */
1215 xhv->xhv_fill--; /* HvFILL(hv)-- */
1216 /* I think we don't actually need to keep track of the longest length,
1217 merely flag if anything is too long. But for the moment while
1218 developing this code I'll track it. */
1219 if (left_length > longest_chain)
1220 longest_chain = left_length;
1221 if (right_length > longest_chain)
1222 longest_chain = right_length;
1226 /* Pick your policy for "hashing isn't working" here: */
1227 if (longest_chain <= HV_MAX_LENGTH_BEFORE_SPLIT /* split worked? */
1232 if (hv == PL_strtab) {
1233 /* Urg. Someone is doing something nasty to the string table.
1238 /* Awooga. Awooga. Pathological data. */
1239 /*PerlIO_printf(PerlIO_stderr(), "%p %d of %d with %d/%d buckets\n", hv,
1240 longest_chain, HvTOTALKEYS(hv), HvFILL(hv), 1+HvMAX(hv));*/
1243 Newxz(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1244 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1246 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1249 was_shared = HvSHAREKEYS(hv);
1252 HvSHAREKEYS_off(hv);
1257 for (i=0; i<newsize; i++,aep++) {
1258 register HE *entry = *aep;
1260 /* We're going to trash this HE's next pointer when we chain it
1261 into the new hash below, so store where we go next. */
1262 HE * const next = HeNEXT(entry);
1267 PERL_HASH_INTERNAL(hash, HeKEY(entry), HeKLEN(entry));
1272 = save_hek_flags(HeKEY(entry), HeKLEN(entry),
1273 hash, HeKFLAGS(entry));
1274 unshare_hek (HeKEY_hek(entry));
1275 HeKEY_hek(entry) = new_hek;
1277 /* Not shared, so simply write the new hash in. */
1278 HeHASH(entry) = hash;
1280 /*PerlIO_printf(PerlIO_stderr(), "%d ", HeKFLAGS(entry));*/
1281 HEK_REHASH_on(HeKEY_hek(entry));
1282 /*PerlIO_printf(PerlIO_stderr(), "%d\n", HeKFLAGS(entry));*/
1284 /* Copy oentry to the correct new chain. */
1285 bep = ((HE**)a) + (hash & (I32) xhv->xhv_max);
1287 xhv->xhv_fill++; /* HvFILL(hv)++ */
1288 HeNEXT(entry) = *bep;
1294 Safefree (HvARRAY(hv));
1295 HvARRAY(hv) = (HE **)a;
1299 Perl_hv_ksplit(pTHX_ HV *hv, IV newmax)
1302 register XPVHV* xhv = (XPVHV*)SvANY(hv);
1303 const I32 oldsize = (I32) xhv->xhv_max+1; /* HvMAX(hv)+1 (sick) */
1304 register I32 newsize;
1309 register HE **oentry;
1311 newsize = (I32) newmax; /* possible truncation here */
1312 if (newsize != newmax || newmax <= oldsize)
1314 while ((newsize & (1 + ~newsize)) != newsize) {
1315 newsize &= ~(newsize & (1 + ~newsize)); /* get proper power of 2 */
1317 if (newsize < newmax)
1319 if (newsize < newmax)
1320 return; /* overflow detection */
1322 a = (char *) HvARRAY(hv);
1325 #if defined(STRANGE_MALLOC) || defined(MYMALLOC)
1326 Renew(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1327 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1333 Copy(&a[oldsize * sizeof(HE*)], &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1336 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1337 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1342 Copy(HvARRAY(hv), a, oldsize * sizeof(HE*), char);
1344 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1346 if (oldsize >= 64) {
1347 offer_nice_chunk(HvARRAY(hv),
1348 PERL_HV_ARRAY_ALLOC_BYTES(oldsize)
1349 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0));
1352 Safefree(HvARRAY(hv));
1355 Zero(&a[oldsize * sizeof(HE*)], (newsize-oldsize) * sizeof(HE*), char); /* zero 2nd half*/
1358 Newxz(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize), char);
1360 xhv->xhv_max = --newsize; /* HvMAX(hv) = --newsize */
1361 HvARRAY(hv) = (HE **) a;
1362 if (!xhv->xhv_fill /* !HvFILL(hv) */) /* skip rest if no entries */
1366 for (i=0; i<oldsize; i++,aep++) {
1367 if (!*aep) /* non-existent */
1369 for (oentry = aep, entry = *aep; entry; entry = *oentry) {
1370 register I32 j = (HeHASH(entry) & newsize);
1374 *oentry = HeNEXT(entry);
1375 if (!(HeNEXT(entry) = aep[j]))
1376 xhv->xhv_fill++; /* HvFILL(hv)++ */
1381 oentry = &HeNEXT(entry);
1383 if (!*aep) /* everything moved */
1384 xhv->xhv_fill--; /* HvFILL(hv)-- */
1391 Creates a new HV. The reference count is set to 1.
1399 register XPVHV* xhv;
1400 HV * const hv = (HV*)newSV(0);
1402 sv_upgrade((SV *)hv, SVt_PVHV);
1403 xhv = (XPVHV*)SvANY(hv);
1406 #ifndef NODEFAULT_SHAREKEYS
1407 HvSHAREKEYS_on(hv); /* key-sharing on by default */
1410 xhv->xhv_max = 7; /* HvMAX(hv) = 7 (start with 8 buckets) */
1411 xhv->xhv_fill = 0; /* HvFILL(hv) = 0 */
1416 Perl_newHVhv(pTHX_ HV *ohv)
1418 HV * const hv = newHV();
1419 STRLEN hv_max, hv_fill;
1421 if (!ohv || (hv_fill = HvFILL(ohv)) == 0)
1423 hv_max = HvMAX(ohv);
1425 if (!SvMAGICAL((SV *)ohv)) {
1426 /* It's an ordinary hash, so copy it fast. AMS 20010804 */
1428 const bool shared = !!HvSHAREKEYS(ohv);
1429 HE **ents, ** const oents = (HE **)HvARRAY(ohv);
1431 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(hv_max+1), char);
1434 /* In each bucket... */
1435 for (i = 0; i <= hv_max; i++) {
1437 HE *oent = oents[i];
1444 /* Copy the linked list of entries. */
1445 for (; oent; oent = HeNEXT(oent)) {
1446 const U32 hash = HeHASH(oent);
1447 const char * const key = HeKEY(oent);
1448 const STRLEN len = HeKLEN(oent);
1449 const int flags = HeKFLAGS(oent);
1450 HE * const ent = new_HE();
1452 HeVAL(ent) = newSVsv(HeVAL(oent));
1454 = shared ? share_hek_flags(key, len, hash, flags)
1455 : save_hek_flags(key, len, hash, flags);
1466 HvFILL(hv) = hv_fill;
1467 HvTOTALKEYS(hv) = HvTOTALKEYS(ohv);
1471 /* Iterate over ohv, copying keys and values one at a time. */
1473 const I32 riter = HvRITER_get(ohv);
1474 HE * const eiter = HvEITER_get(ohv);
1476 /* Can we use fewer buckets? (hv_max is always 2^n-1) */
1477 while (hv_max && hv_max + 1 >= hv_fill * 2)
1478 hv_max = hv_max / 2;
1482 while ((entry = hv_iternext_flags(ohv, 0))) {
1483 hv_store_flags(hv, HeKEY(entry), HeKLEN(entry),
1484 newSVsv(HeVAL(entry)), HeHASH(entry),
1487 HvRITER_set(ohv, riter);
1488 HvEITER_set(ohv, eiter);
1495 Perl_hv_free_ent(pTHX_ HV *hv, register HE *entry)
1503 if (val && isGV(val) && GvCVu(val) && HvNAME_get(hv))
1504 PL_sub_generation++; /* may be deletion of method from stash */
1506 if (HeKLEN(entry) == HEf_SVKEY) {
1507 SvREFCNT_dec(HeKEY_sv(entry));
1508 Safefree(HeKEY_hek(entry));
1510 else if (HvSHAREKEYS(hv))
1511 unshare_hek(HeKEY_hek(entry));
1513 Safefree(HeKEY_hek(entry));
1518 Perl_hv_delayfree_ent(pTHX_ HV *hv, register HE *entry)
1523 /* SvREFCNT_inc to counter the SvREFCNT_dec in hv_free_ent */
1524 sv_2mortal(SvREFCNT_inc(HeVAL(entry))); /* free between statements */
1525 if (HeKLEN(entry) == HEf_SVKEY) {
1526 sv_2mortal(SvREFCNT_inc(HeKEY_sv(entry)));
1528 hv_free_ent(hv, entry);
1532 =for apidoc hv_clear
1534 Clears a hash, making it empty.
1540 Perl_hv_clear(pTHX_ HV *hv)
1543 register XPVHV* xhv;
1547 DEBUG_A(Perl_hv_assert(aTHX_ hv));
1549 xhv = (XPVHV*)SvANY(hv);
1551 if (SvREADONLY(hv) && HvARRAY(hv) != NULL) {
1552 /* restricted hash: convert all keys to placeholders */
1554 for (i = 0; i <= xhv->xhv_max; i++) {
1555 HE *entry = (HvARRAY(hv))[i];
1556 for (; entry; entry = HeNEXT(entry)) {
1557 /* not already placeholder */
1558 if (HeVAL(entry) != &PL_sv_placeholder) {
1559 if (HeVAL(entry) && SvREADONLY(HeVAL(entry))) {
1560 SV* const keysv = hv_iterkeysv(entry);
1562 "Attempt to delete readonly key '%"SVf"' from a restricted hash",
1565 SvREFCNT_dec(HeVAL(entry));
1566 HeVAL(entry) = &PL_sv_placeholder;
1567 HvPLACEHOLDERS(hv)++;
1575 HvPLACEHOLDERS_set(hv, 0);
1577 (void)memzero(HvARRAY(hv),
1578 (xhv->xhv_max+1 /* HvMAX(hv)+1 */) * sizeof(HE*));
1583 HvHASKFLAGS_off(hv);
1587 HvEITER_set(hv, NULL);
1592 =for apidoc hv_clear_placeholders
1594 Clears any placeholders from a hash. If a restricted hash has any of its keys
1595 marked as readonly and the key is subsequently deleted, the key is not actually
1596 deleted but is marked by assigning it a value of &PL_sv_placeholder. This tags
1597 it so it will be ignored by future operations such as iterating over the hash,
1598 but will still allow the hash to have a value reassigned to the key at some
1599 future point. This function clears any such placeholder keys from the hash.
1600 See Hash::Util::lock_keys() for an example of its use.
1606 Perl_hv_clear_placeholders(pTHX_ HV *hv)
1609 I32 items = (I32)HvPLACEHOLDERS_get(hv);
1617 /* Loop down the linked list heads */
1619 HE **oentry = &(HvARRAY(hv))[i];
1622 while ((entry = *oentry)) {
1623 if (HeVAL(entry) == &PL_sv_placeholder) {
1624 *oentry = HeNEXT(entry);
1625 if (first && !*oentry)
1626 HvFILL(hv)--; /* This linked list is now empty. */
1627 if (entry == HvEITER_get(hv))
1630 hv_free_ent(hv, entry);
1634 HvTOTALKEYS(hv) -= (IV)HvPLACEHOLDERS_get(hv);
1635 if (HvKEYS(hv) == 0)
1636 HvHASKFLAGS_off(hv);
1637 HvPLACEHOLDERS_set(hv, 0);
1641 oentry = &HeNEXT(entry);
1646 /* You can't get here, hence assertion should always fail. */
1647 assert (items == 0);
1652 S_hfreeentries(pTHX_ HV *hv)
1654 /* This is the array that we're going to restore */
1663 /* If the hash is actually a symbol table with a name, look after the
1665 struct xpvhv_aux *iter = HvAUX(hv);
1667 name = iter->xhv_name;
1668 iter->xhv_name = NULL;
1673 orig_array = HvARRAY(hv);
1674 /* orig_array remains unchanged throughout the loop. If after freeing all
1675 the entries it turns out that one of the little blighters has triggered
1676 an action that has caused HvARRAY to be re-allocated, then we set
1677 array to the new HvARRAY, and try again. */
1680 /* This is the one we're going to try to empty. First time round
1681 it's the original array. (Hopefully there will only be 1 time
1683 HE ** const array = HvARRAY(hv);
1686 /* Because we have taken xhv_name out, the only allocated pointer
1687 in the aux structure that might exist is the backreference array.
1692 struct xpvhv_aux *iter = HvAUX(hv);
1693 /* If there are weak references to this HV, we need to avoid
1694 freeing them up here. In particular we need to keep the AV
1695 visible as what we're deleting might well have weak references
1696 back to this HV, so the for loop below may well trigger
1697 the removal of backreferences from this array. */
1699 if (iter->xhv_backreferences) {
1700 /* So donate them to regular backref magic to keep them safe.
1701 The sv_magic will increase the reference count of the AV,
1702 so we need to drop it first. */
1703 SvREFCNT_dec(iter->xhv_backreferences);
1704 if (AvFILLp(iter->xhv_backreferences) == -1) {
1705 /* Turns out that the array is empty. Just free it. */
1706 SvREFCNT_dec(iter->xhv_backreferences);
1709 sv_magic((SV*)hv, (SV*)iter->xhv_backreferences,
1710 PERL_MAGIC_backref, NULL, 0);
1712 iter->xhv_backreferences = NULL;
1715 entry = iter->xhv_eiter; /* HvEITER(hv) */
1716 if (entry && HvLAZYDEL(hv)) { /* was deleted earlier? */
1718 hv_free_ent(hv, entry);
1720 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1721 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1723 /* There are now no allocated pointers in the aux structure. */
1725 SvFLAGS(hv) &= ~SVf_OOK; /* Goodbye, aux structure. */
1726 /* What aux structure? */
1729 /* make everyone else think the array is empty, so that the destructors
1730 * called for freed entries can't recusively mess with us */
1733 ((XPVHV*) SvANY(hv))->xhv_keys = 0;
1737 /* Loop down the linked list heads */
1738 HE *entry = array[i];
1741 register HE * const oentry = entry;
1742 entry = HeNEXT(entry);
1743 hv_free_ent(hv, oentry);
1747 /* As there are no allocated pointers in the aux structure, it's now
1748 safe to free the array we just cleaned up, if it's not the one we're
1749 going to put back. */
1750 if (array != orig_array) {
1755 /* Good. No-one added anything this time round. */
1760 /* Someone attempted to iterate or set the hash name while we had
1761 the array set to 0. We'll catch backferences on the next time
1762 round the while loop. */
1763 assert(HvARRAY(hv));
1765 if (HvAUX(hv)->xhv_name) {
1766 unshare_hek_or_pvn(HvAUX(hv)->xhv_name, 0, 0, 0);
1770 if (--attempts == 0) {
1771 Perl_die(aTHX_ "panic: hfreeentries failed to free hash - something is repeatedly re-creating entries");
1775 HvARRAY(hv) = orig_array;
1777 /* If the hash was actually a symbol table, put the name back. */
1779 /* We have restored the original array. If name is non-NULL, then
1780 the original array had an aux structure at the end. So this is
1782 SvFLAGS(hv) |= SVf_OOK;
1783 HvAUX(hv)->xhv_name = name;
1788 =for apidoc hv_undef
1796 Perl_hv_undef(pTHX_ HV *hv)
1799 register XPVHV* xhv;
1804 DEBUG_A(Perl_hv_assert(aTHX_ hv));
1805 xhv = (XPVHV*)SvANY(hv);
1807 if ((name = HvNAME_get(hv))) {
1809 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);
1822 static struct xpvhv_aux*
1823 S_hv_auxinit(HV *hv) {
1824 struct xpvhv_aux *iter;
1828 Newxz(array, PERL_HV_ARRAY_ALLOC_BYTES(HvMAX(hv) + 1)
1829 + sizeof(struct xpvhv_aux), char);
1831 array = (char *) HvARRAY(hv);
1832 Renew(array, PERL_HV_ARRAY_ALLOC_BYTES(HvMAX(hv) + 1)
1833 + sizeof(struct xpvhv_aux), char);
1835 HvARRAY(hv) = (HE**) array;
1836 /* SvOOK_on(hv) attacks the IV flags. */
1837 SvFLAGS(hv) |= SVf_OOK;
1840 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1841 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1843 iter->xhv_backreferences = 0;
1848 =for apidoc hv_iterinit
1850 Prepares a starting point to traverse a hash table. Returns the number of
1851 keys in the hash (i.e. the same as C<HvKEYS(tb)>). The return value is
1852 currently only meaningful for hashes without tie magic.
1854 NOTE: Before version 5.004_65, C<hv_iterinit> used to return the number of
1855 hash buckets that happen to be in use. If you still need that esoteric
1856 value, you can get it through the macro C<HvFILL(tb)>.
1863 Perl_hv_iterinit(pTHX_ HV *hv)
1866 Perl_croak(aTHX_ "Bad hash");
1869 struct xpvhv_aux * const iter = HvAUX(hv);
1870 HE * const entry = iter->xhv_eiter; /* HvEITER(hv) */
1871 if (entry && HvLAZYDEL(hv)) { /* was deleted earlier? */
1873 hv_free_ent(hv, entry);
1875 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1876 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1881 /* used to be xhv->xhv_fill before 5.004_65 */
1882 return HvTOTALKEYS(hv);
1886 Perl_hv_riter_p(pTHX_ HV *hv) {
1887 struct xpvhv_aux *iter;
1890 Perl_croak(aTHX_ "Bad hash");
1892 iter = SvOOK(hv) ? HvAUX(hv) : hv_auxinit(hv);
1893 return &(iter->xhv_riter);
1897 Perl_hv_eiter_p(pTHX_ HV *hv) {
1898 struct xpvhv_aux *iter;
1901 Perl_croak(aTHX_ "Bad hash");
1903 iter = SvOOK(hv) ? HvAUX(hv) : hv_auxinit(hv);
1904 return &(iter->xhv_eiter);
1908 Perl_hv_riter_set(pTHX_ HV *hv, I32 riter) {
1909 struct xpvhv_aux *iter;
1912 Perl_croak(aTHX_ "Bad hash");
1920 iter = hv_auxinit(hv);
1922 iter->xhv_riter = riter;
1926 Perl_hv_eiter_set(pTHX_ HV *hv, HE *eiter) {
1927 struct xpvhv_aux *iter;
1930 Perl_croak(aTHX_ "Bad hash");
1935 /* 0 is the default so don't go malloc()ing a new structure just to
1940 iter = hv_auxinit(hv);
1942 iter->xhv_eiter = eiter;
1946 Perl_hv_name_set(pTHX_ HV *hv, const char *name, I32 len, int flags)
1949 struct xpvhv_aux *iter;
1952 PERL_UNUSED_ARG(flags);
1956 if (iter->xhv_name) {
1957 unshare_hek_or_pvn(iter->xhv_name, 0, 0, 0);
1963 iter = hv_auxinit(hv);
1965 PERL_HASH(hash, name, len);
1966 iter->xhv_name = name ? share_hek(name, len, hash) : 0;
1970 Perl_hv_backreferences_p(pTHX_ HV *hv) {
1971 struct xpvhv_aux * const iter = SvOOK(hv) ? HvAUX(hv) : hv_auxinit(hv);
1972 return &(iter->xhv_backreferences);
1976 Perl_hv_kill_backrefs(pTHX_ HV *hv) {
1982 av = HvAUX(hv)->xhv_backreferences;
1985 HvAUX(hv)->xhv_backreferences = 0;
1986 Perl_sv_kill_backrefs(aTHX_ (SV*) hv, av);
1991 hv_iternext is implemented as a macro in hv.h
1993 =for apidoc hv_iternext
1995 Returns entries from a hash iterator. See C<hv_iterinit>.
1997 You may call C<hv_delete> or C<hv_delete_ent> on the hash entry that the
1998 iterator currently points to, without losing your place or invalidating your
1999 iterator. Note that in this case the current entry is deleted from the hash
2000 with your iterator holding the last reference to it. Your iterator is flagged
2001 to free the entry on the next call to C<hv_iternext>, so you must not discard
2002 your iterator immediately else the entry will leak - call C<hv_iternext> to
2003 trigger the resource deallocation.
2005 =for apidoc hv_iternext_flags
2007 Returns entries from a hash iterator. See C<hv_iterinit> and C<hv_iternext>.
2008 The C<flags> value will normally be zero; if HV_ITERNEXT_WANTPLACEHOLDERS is
2009 set the placeholders keys (for restricted hashes) will be returned in addition
2010 to normal keys. By default placeholders are automatically skipped over.
2011 Currently a placeholder is implemented with a value that is
2012 C<&Perl_sv_placeholder>. Note that the implementation of placeholders and
2013 restricted hashes may change, and the implementation currently is
2014 insufficiently abstracted for any change to be tidy.
2020 Perl_hv_iternext_flags(pTHX_ HV *hv, I32 flags)
2023 register XPVHV* xhv;
2027 struct xpvhv_aux *iter;
2030 Perl_croak(aTHX_ "Bad hash");
2031 xhv = (XPVHV*)SvANY(hv);
2034 /* Too many things (well, pp_each at least) merrily assume that you can
2035 call iv_iternext without calling hv_iterinit, so we'll have to deal
2041 oldentry = entry = iter->xhv_eiter; /* HvEITER(hv) */
2043 if ((mg = SvTIED_mg((SV*)hv, PERL_MAGIC_tied))) {
2044 SV * const key = sv_newmortal();
2046 sv_setsv(key, HeSVKEY_force(entry));
2047 SvREFCNT_dec(HeSVKEY(entry)); /* get rid of previous key */
2053 /* one HE per MAGICAL hash */
2054 iter->xhv_eiter = entry = new_HE(); /* HvEITER(hv) = new_HE() */
2056 Newxz(k, HEK_BASESIZE + sizeof(SV*), char);
2058 HeKEY_hek(entry) = hek;
2059 HeKLEN(entry) = HEf_SVKEY;
2061 magic_nextpack((SV*) hv,mg,key);
2063 /* force key to stay around until next time */
2064 HeSVKEY_set(entry, SvREFCNT_inc(key));
2065 return entry; /* beware, hent_val is not set */
2068 SvREFCNT_dec(HeVAL(entry));
2069 Safefree(HeKEY_hek(entry));
2071 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
2074 #ifdef DYNAMIC_ENV_FETCH /* set up %ENV for iteration */
2075 if (!entry && SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env)) {
2078 /* The prime_env_iter() on VMS just loaded up new hash values
2079 * so the iteration count needs to be reset back to the beginning
2083 oldentry = entry = iter->xhv_eiter; /* HvEITER(hv) */
2088 /* hv_iterint now ensures this. */
2089 assert (HvARRAY(hv));
2091 /* At start of hash, entry is NULL. */
2094 entry = HeNEXT(entry);
2095 if (!(flags & HV_ITERNEXT_WANTPLACEHOLDERS)) {
2097 * Skip past any placeholders -- don't want to include them in
2100 while (entry && HeVAL(entry) == &PL_sv_placeholder) {
2101 entry = HeNEXT(entry);
2106 /* OK. Come to the end of the current list. Grab the next one. */
2108 iter->xhv_riter++; /* HvRITER(hv)++ */
2109 if (iter->xhv_riter > (I32)xhv->xhv_max /* HvRITER(hv) > HvMAX(hv) */) {
2110 /* There is no next one. End of the hash. */
2111 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
2114 entry = (HvARRAY(hv))[iter->xhv_riter];
2116 if (!(flags & HV_ITERNEXT_WANTPLACEHOLDERS)) {
2117 /* If we have an entry, but it's a placeholder, don't count it.
2119 while (entry && HeVAL(entry) == &PL_sv_placeholder)
2120 entry = HeNEXT(entry);
2122 /* Will loop again if this linked list starts NULL
2123 (for HV_ITERNEXT_WANTPLACEHOLDERS)
2124 or if we run through it and find only placeholders. */
2127 if (oldentry && HvLAZYDEL(hv)) { /* was deleted earlier? */
2129 hv_free_ent(hv, oldentry);
2132 /*if (HvREHASH(hv) && entry && !HeKREHASH(entry))
2133 PerlIO_printf(PerlIO_stderr(), "Awooga %p %p\n", hv, entry);*/
2135 iter->xhv_eiter = entry; /* HvEITER(hv) = entry */
2140 =for apidoc hv_iterkey
2142 Returns the key from the current position of the hash iterator. See
2149 Perl_hv_iterkey(pTHX_ register HE *entry, I32 *retlen)
2151 if (HeKLEN(entry) == HEf_SVKEY) {
2153 char * const p = SvPV(HeKEY_sv(entry), len);
2158 *retlen = HeKLEN(entry);
2159 return HeKEY(entry);
2163 /* unlike hv_iterval(), this always returns a mortal copy of the key */
2165 =for apidoc hv_iterkeysv
2167 Returns the key as an C<SV*> from the current position of the hash
2168 iterator. The return value will always be a mortal copy of the key. Also
2175 Perl_hv_iterkeysv(pTHX_ register HE *entry)
2177 return sv_2mortal(newSVhek(HeKEY_hek(entry)));
2181 =for apidoc hv_iterval
2183 Returns the value from the current position of the hash iterator. See
2190 Perl_hv_iterval(pTHX_ HV *hv, register HE *entry)
2192 if (SvRMAGICAL(hv)) {
2193 if (mg_find((SV*)hv, PERL_MAGIC_tied)) {
2194 SV* const sv = sv_newmortal();
2195 if (HeKLEN(entry) == HEf_SVKEY)
2196 mg_copy((SV*)hv, sv, (char*)HeKEY_sv(entry), HEf_SVKEY);
2198 mg_copy((SV*)hv, sv, HeKEY(entry), HeKLEN(entry));
2202 return HeVAL(entry);
2206 =for apidoc hv_iternextsv
2208 Performs an C<hv_iternext>, C<hv_iterkey>, and C<hv_iterval> in one
2215 Perl_hv_iternextsv(pTHX_ HV *hv, char **key, I32 *retlen)
2217 HE * const he = hv_iternext_flags(hv, 0);
2221 *key = hv_iterkey(he, retlen);
2222 return hv_iterval(hv, he);
2229 =for apidoc hv_magic
2231 Adds magic to a hash. See C<sv_magic>.
2236 /* possibly free a shared string if no one has access to it
2237 * len and hash must both be valid for str.
2240 Perl_unsharepvn(pTHX_ const char *str, I32 len, U32 hash)
2242 unshare_hek_or_pvn (NULL, str, len, hash);
2247 Perl_unshare_hek(pTHX_ HEK *hek)
2249 unshare_hek_or_pvn(hek, NULL, 0, 0);
2252 /* possibly free a shared string if no one has access to it
2253 hek if non-NULL takes priority over the other 3, else str, len and hash
2254 are used. If so, len and hash must both be valid for str.
2257 S_unshare_hek_or_pvn(pTHX_ const HEK *hek, const char *str, I32 len, U32 hash)
2260 register XPVHV* xhv;
2262 register HE **oentry;
2265 bool is_utf8 = FALSE;
2267 const char * const save = str;
2268 struct shared_he *he = NULL;
2271 /* Find the shared he which is just before us in memory. */
2272 he = (struct shared_he *)(((char *)hek)
2273 - STRUCT_OFFSET(struct shared_he,
2276 /* Assert that the caller passed us a genuine (or at least consistent)
2278 assert (he->shared_he_he.hent_hek == hek);
2281 if (he->shared_he_he.he_valu.hent_refcount - 1) {
2282 --he->shared_he_he.he_valu.hent_refcount;
2283 UNLOCK_STRTAB_MUTEX;
2286 UNLOCK_STRTAB_MUTEX;
2288 hash = HEK_HASH(hek);
2289 } else if (len < 0) {
2290 STRLEN tmplen = -len;
2292 /* See the note in hv_fetch(). --jhi */
2293 str = (char*)bytes_from_utf8((U8*)str, &tmplen, &is_utf8);
2296 k_flags = HVhek_UTF8;
2298 k_flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
2301 /* what follows was the moral equivalent of:
2302 if ((Svp = hv_fetch(PL_strtab, tmpsv, FALSE, hash))) {
2304 hv_delete(PL_strtab, str, len, G_DISCARD, hash);
2306 xhv = (XPVHV*)SvANY(PL_strtab);
2307 /* assert(xhv_array != 0) */
2309 first = oentry = &(HvARRAY(PL_strtab))[hash & (I32) HvMAX(PL_strtab)];
2311 const HE *const he_he = &(he->shared_he_he);
2312 for (entry = *oentry; entry; oentry = &HeNEXT(entry), entry = *oentry) {
2319 const int flags_masked = k_flags & HVhek_MASK;
2320 for (entry = *oentry; entry; oentry = &HeNEXT(entry), entry = *oentry) {
2321 if (HeHASH(entry) != hash) /* strings can't be equal */
2323 if (HeKLEN(entry) != len)
2325 if (HeKEY(entry) != str && memNE(HeKEY(entry),str,len)) /* is this it? */
2327 if (HeKFLAGS(entry) != flags_masked)
2335 if (--he->shared_he_he.he_valu.hent_refcount == 0) {
2336 *oentry = HeNEXT(entry);
2338 /* There are now no entries in our slot. */
2339 xhv->xhv_fill--; /* HvFILL(hv)-- */
2342 xhv->xhv_keys--; /* HvKEYS(hv)-- */
2346 UNLOCK_STRTAB_MUTEX;
2347 if (!found && ckWARN_d(WARN_INTERNAL))
2348 Perl_warner(aTHX_ packWARN(WARN_INTERNAL),
2349 "Attempt to free non-existent shared string '%s'%s"
2351 hek ? HEK_KEY(hek) : str,
2352 ((k_flags & HVhek_UTF8) ? " (utf8)" : "") pTHX__VALUE);
2353 if (k_flags & HVhek_FREEKEY)
2357 /* get a (constant) string ptr from the global string table
2358 * string will get added if it is not already there.
2359 * len and hash must both be valid for str.
2362 Perl_share_hek(pTHX_ const char *str, I32 len, register U32 hash)
2364 bool is_utf8 = FALSE;
2366 const char * const save = str;
2369 STRLEN tmplen = -len;
2371 /* See the note in hv_fetch(). --jhi */
2372 str = (char*)bytes_from_utf8((U8*)str, &tmplen, &is_utf8);
2374 /* If we were able to downgrade here, then than means that we were passed
2375 in a key which only had chars 0-255, but was utf8 encoded. */
2378 /* If we found we were able to downgrade the string to bytes, then
2379 we should flag that it needs upgrading on keys or each. Also flag
2380 that we need share_hek_flags to free the string. */
2382 flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
2385 return share_hek_flags (str, len, hash, flags);
2389 S_share_hek_flags(pTHX_ const char *str, I32 len, register U32 hash, int flags)
2393 const int flags_masked = flags & HVhek_MASK;
2394 const U32 hindex = hash & (I32) HvMAX(PL_strtab);
2396 /* what follows is the moral equivalent of:
2398 if (!(Svp = hv_fetch(PL_strtab, str, len, FALSE)))
2399 hv_store(PL_strtab, str, len, NULL, hash);
2401 Can't rehash the shared string table, so not sure if it's worth
2402 counting the number of entries in the linked list
2404 register XPVHV * const xhv = (XPVHV*)SvANY(PL_strtab);
2405 /* assert(xhv_array != 0) */
2407 entry = (HvARRAY(PL_strtab))[hindex];
2408 for (;entry; entry = HeNEXT(entry)) {
2409 if (HeHASH(entry) != hash) /* strings can't be equal */
2411 if (HeKLEN(entry) != len)
2413 if (HeKEY(entry) != str && memNE(HeKEY(entry),str,len)) /* is this it? */
2415 if (HeKFLAGS(entry) != flags_masked)
2421 /* What used to be head of the list.
2422 If this is NULL, then we're the first entry for this slot, which
2423 means we need to increate fill. */
2424 struct shared_he *new_entry;
2427 HE **const head = &HvARRAY(PL_strtab)[hindex];
2428 HE *const next = *head;
2430 /* We don't actually store a HE from the arena and a regular HEK.
2431 Instead we allocate one chunk of memory big enough for both,
2432 and put the HEK straight after the HE. This way we can find the
2433 HEK directly from the HE.
2436 Newx(k, STRUCT_OFFSET(struct shared_he,
2437 shared_he_hek.hek_key[0]) + len + 2, char);
2438 new_entry = (struct shared_he *)k;
2439 entry = &(new_entry->shared_he_he);
2440 hek = &(new_entry->shared_he_hek);
2442 Copy(str, HEK_KEY(hek), len, char);
2443 HEK_KEY(hek)[len] = 0;
2445 HEK_HASH(hek) = hash;
2446 HEK_FLAGS(hek) = (unsigned char)flags_masked;
2448 /* Still "point" to the HEK, so that other code need not know what
2450 HeKEY_hek(entry) = hek;
2451 entry->he_valu.hent_refcount = 0;
2452 HeNEXT(entry) = next;
2455 xhv->xhv_keys++; /* HvKEYS(hv)++ */
2456 if (!next) { /* initial entry? */
2457 xhv->xhv_fill++; /* HvFILL(hv)++ */
2458 } else if (xhv->xhv_keys > (IV)xhv->xhv_max /* HvKEYS(hv) > HvMAX(hv) */) {
2463 ++entry->he_valu.hent_refcount;
2464 UNLOCK_STRTAB_MUTEX;
2466 if (flags & HVhek_FREEKEY)
2469 return HeKEY_hek(entry);
2473 Perl_hv_placeholders_p(pTHX_ HV *hv)
2476 MAGIC *mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2479 mg = sv_magicext((SV*)hv, 0, PERL_MAGIC_rhash, 0, 0, 0);
2482 Perl_die(aTHX_ "panic: hv_placeholders_p");
2485 return &(mg->mg_len);
2490 Perl_hv_placeholders_get(pTHX_ HV *hv)
2493 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2495 return mg ? mg->mg_len : 0;
2499 Perl_hv_placeholders_set(pTHX_ HV *hv, I32 ph)
2502 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2507 if (!sv_magicext((SV*)hv, 0, PERL_MAGIC_rhash, 0, 0, ph))
2508 Perl_die(aTHX_ "panic: hv_placeholders_set");
2510 /* else we don't need to add magic to record 0 placeholders. */
2514 =for apidoc hv_assert
2516 Check that a hash is in an internally consistent state.
2522 Perl_hv_assert(pTHX_ HV *hv)
2527 int placeholders = 0;
2530 const I32 riter = HvRITER_get(hv);
2531 HE *eiter = HvEITER_get(hv);
2533 (void)hv_iterinit(hv);
2535 while ((entry = hv_iternext_flags(hv, HV_ITERNEXT_WANTPLACEHOLDERS))) {
2536 /* sanity check the values */
2537 if (HeVAL(entry) == &PL_sv_placeholder) {
2542 /* sanity check the keys */
2543 if (HeSVKEY(entry)) {
2544 /*EMPTY*/ /* Don't know what to check on SV keys. */
2545 } else if (HeKUTF8(entry)) {
2547 if (HeKWASUTF8(entry)) {
2548 PerlIO_printf(Perl_debug_log,
2549 "hash key has both WASUFT8 and UTF8: '%.*s'\n",
2550 (int) HeKLEN(entry), HeKEY(entry));
2553 } else if (HeKWASUTF8(entry)) {
2557 if (!SvTIED_mg((SV*)hv, PERL_MAGIC_tied)) {
2558 if (HvUSEDKEYS(hv) != real) {
2559 PerlIO_printf(Perl_debug_log, "Count %d key(s), but hash reports %d\n",
2560 (int) real, (int) HvUSEDKEYS(hv));
2563 if (HvPLACEHOLDERS_get(hv) != placeholders) {
2564 PerlIO_printf(Perl_debug_log,
2565 "Count %d placeholder(s), but hash reports %d\n",
2566 (int) placeholders, (int) HvPLACEHOLDERS_get(hv));
2570 if (withflags && ! HvHASKFLAGS(hv)) {
2571 PerlIO_printf(Perl_debug_log,
2572 "Hash has HASKFLAGS off but I count %d key(s) with flags\n",
2579 HvRITER_set(hv, riter); /* Restore hash iterator state */
2580 HvEITER_set(hv, eiter);
2585 * c-indentation-style: bsd
2587 * indent-tabs-mode: t
2590 * ex: set ts=8 sts=4 sw=4 noet: