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";
45 Newx(he, PERL_ARENA_SIZE/sizeof(HE), HE);
46 HeNEXT(he) = (HE*) PL_body_arenaroots[HE_SVSLOT];
47 PL_body_arenaroots[HE_SVSLOT] = he;
49 heend = &he[PERL_ARENA_SIZE / sizeof(HE) - 1];
50 PL_body_roots[HE_SVSLOT] = ++he;
52 HeNEXT(he) = (HE*)(he + 1);
60 #define new_HE() (HE*)safemalloc(sizeof(HE))
61 #define del_HE(p) safefree((char*)p)
70 void ** const root = &PL_body_roots[HE_SVSLOT];
81 #define new_HE() new_he()
85 HeNEXT(p) = (HE*)(PL_body_roots[HE_SVSLOT]); \
86 PL_body_roots[HE_SVSLOT] = p; \
95 S_save_hek_flags(pTHX_ const char *str, I32 len, U32 hash, int flags)
97 const int flags_masked = flags & HVhek_MASK;
101 Newx(k, HEK_BASESIZE + len + 2, char);
103 Copy(str, HEK_KEY(hek), len, char);
104 HEK_KEY(hek)[len] = 0;
106 HEK_HASH(hek) = hash;
107 HEK_FLAGS(hek) = (unsigned char)flags_masked;
109 if (flags & HVhek_FREEKEY)
114 /* free the pool of temporary HE/HEK pairs returned by hv_fetch_ent
118 Perl_free_tied_hv_pool(pTHX)
121 HE *he = PL_hv_fetch_ent_mh;
124 Safefree(HeKEY_hek(he));
128 PL_hv_fetch_ent_mh = Nullhe;
131 #if defined(USE_ITHREADS)
133 Perl_hek_dup(pTHX_ HEK *source, CLONE_PARAMS* param)
135 HEK *shared = (HEK*)ptr_table_fetch(PL_ptr_table, source);
137 PERL_UNUSED_ARG(param);
140 /* We already shared this hash key. */
141 (void)share_hek_hek(shared);
145 = share_hek_flags(HEK_KEY(source), HEK_LEN(source),
146 HEK_HASH(source), HEK_FLAGS(source));
147 ptr_table_store(PL_ptr_table, source, shared);
153 Perl_he_dup(pTHX_ const HE *e, bool shared, CLONE_PARAMS* param)
159 /* look for it in the table first */
160 ret = (HE*)ptr_table_fetch(PL_ptr_table, e);
164 /* create anew and remember what it is */
166 ptr_table_store(PL_ptr_table, e, ret);
168 HeNEXT(ret) = he_dup(HeNEXT(e),shared, param);
169 if (HeKLEN(e) == HEf_SVKEY) {
171 Newx(k, HEK_BASESIZE + sizeof(SV*), char);
172 HeKEY_hek(ret) = (HEK*)k;
173 HeKEY_sv(ret) = SvREFCNT_inc(sv_dup(HeKEY_sv(e), param));
176 /* This is hek_dup inlined, which seems to be important for speed
178 HEK * const source = HeKEY_hek(e);
179 HEK *shared = (HEK*)ptr_table_fetch(PL_ptr_table, source);
182 /* We already shared this hash key. */
183 (void)share_hek_hek(shared);
187 = share_hek_flags(HEK_KEY(source), HEK_LEN(source),
188 HEK_HASH(source), HEK_FLAGS(source));
189 ptr_table_store(PL_ptr_table, source, shared);
191 HeKEY_hek(ret) = shared;
194 HeKEY_hek(ret) = save_hek_flags(HeKEY(e), HeKLEN(e), HeHASH(e),
196 HeVAL(ret) = SvREFCNT_inc(sv_dup(HeVAL(e), param));
199 #endif /* USE_ITHREADS */
202 S_hv_notallowed(pTHX_ int flags, const char *key, I32 klen,
205 SV * const sv = sv_newmortal();
206 if (!(flags & HVhek_FREEKEY)) {
207 sv_setpvn(sv, key, klen);
210 /* Need to free saved eventually assign to mortal SV */
211 /* XXX is this line an error ???: SV *sv = sv_newmortal(); */
212 sv_usepvn(sv, (char *) key, klen);
214 if (flags & HVhek_UTF8) {
217 Perl_croak(aTHX_ msg, sv);
220 /* (klen == HEf_SVKEY) is special for MAGICAL hv entries, meaning key slot
223 #define HV_FETCH_ISSTORE 0x01
224 #define HV_FETCH_ISEXISTS 0x02
225 #define HV_FETCH_LVALUE 0x04
226 #define HV_FETCH_JUST_SV 0x08
231 Stores an SV in a hash. The hash key is specified as C<key> and C<klen> is
232 the length of the key. The C<hash> parameter is the precomputed hash
233 value; if it is zero then Perl will compute it. The return value will be
234 NULL if the operation failed or if the value did not need to be actually
235 stored within the hash (as in the case of tied hashes). Otherwise it can
236 be dereferenced to get the original C<SV*>. Note that the caller is
237 responsible for suitably incrementing the reference count of C<val> before
238 the call, and decrementing it if the function returned NULL. Effectively
239 a successful hv_store takes ownership of one reference to C<val>. This is
240 usually what you want; a newly created SV has a reference count of one, so
241 if all your code does is create SVs then store them in a hash, hv_store
242 will own the only reference to the new SV, and your code doesn't need to do
243 anything further to tidy up. hv_store is not implemented as a call to
244 hv_store_ent, and does not create a temporary SV for the key, so if your
245 key data is not already in SV form then use hv_store in preference to
248 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
249 information on how to use this function on tied hashes.
255 Perl_hv_store(pTHX_ HV *hv, const char *key, I32 klen_i32, SV *val, U32 hash)
268 hek = hv_fetch_common (hv, NULL, key, klen, flags,
269 (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), val, hash);
270 return hek ? &HeVAL(hek) : NULL;
273 /* XXX This looks like an ideal candidate to inline */
275 Perl_hv_store_flags(pTHX_ HV *hv, const char *key, I32 klen, SV *val,
276 register U32 hash, int flags)
278 HE * const hek = hv_fetch_common (hv, NULL, key, klen, flags,
279 (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), val, hash);
280 return hek ? &HeVAL(hek) : NULL;
284 =for apidoc hv_store_ent
286 Stores C<val> in a hash. The hash key is specified as C<key>. The C<hash>
287 parameter is the precomputed hash value; if it is zero then Perl will
288 compute it. The return value is the new hash entry so created. It will be
289 NULL if the operation failed or if the value did not need to be actually
290 stored within the hash (as in the case of tied hashes). Otherwise the
291 contents of the return value can be accessed using the C<He?> macros
292 described here. Note that the caller is responsible for suitably
293 incrementing the reference count of C<val> before the call, and
294 decrementing it if the function returned NULL. Effectively a successful
295 hv_store_ent takes ownership of one reference to C<val>. This is
296 usually what you want; a newly created SV has a reference count of one, so
297 if all your code does is create SVs then store them in a hash, hv_store
298 will own the only reference to the new SV, and your code doesn't need to do
299 anything further to tidy up. Note that hv_store_ent only reads the C<key>;
300 unlike C<val> it does not take ownership of it, so maintaining the correct
301 reference count on C<key> is entirely the caller's responsibility. hv_store
302 is not implemented as a call to hv_store_ent, and does not create a temporary
303 SV for the key, so if your key data is not already in SV form then use
304 hv_store in preference to hv_store_ent.
306 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
307 information on how to use this function on tied hashes.
312 /* XXX This looks like an ideal candidate to inline */
314 Perl_hv_store_ent(pTHX_ HV *hv, SV *keysv, SV *val, U32 hash)
316 return hv_fetch_common(hv, keysv, NULL, 0, 0, HV_FETCH_ISSTORE, val, hash);
320 =for apidoc hv_exists
322 Returns a boolean indicating whether the specified hash key exists. The
323 C<klen> is the length of the key.
329 Perl_hv_exists(pTHX_ HV *hv, const char *key, I32 klen_i32)
341 return hv_fetch_common(hv, NULL, key, klen, flags, HV_FETCH_ISEXISTS, 0, 0)
348 Returns the SV which corresponds to the specified key in the hash. The
349 C<klen> is the length of the key. If C<lval> is set then the fetch will be
350 part of a store. Check that the return value is non-null before
351 dereferencing it to an C<SV*>.
353 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
354 information on how to use this function on tied hashes.
360 Perl_hv_fetch(pTHX_ HV *hv, const char *key, I32 klen_i32, I32 lval)
373 hek = hv_fetch_common (hv, NULL, key, klen, flags,
374 lval ? (HV_FETCH_JUST_SV | HV_FETCH_LVALUE) : HV_FETCH_JUST_SV,
376 return hek ? &HeVAL(hek) : NULL;
380 =for apidoc hv_exists_ent
382 Returns a boolean indicating whether the specified hash key exists. C<hash>
383 can be a valid precomputed hash value, or 0 to ask for it to be
389 /* XXX This looks like an ideal candidate to inline */
391 Perl_hv_exists_ent(pTHX_ HV *hv, SV *keysv, U32 hash)
393 return hv_fetch_common(hv, keysv, NULL, 0, 0, HV_FETCH_ISEXISTS, 0, hash)
397 /* returns an HE * structure with the all fields set */
398 /* note that hent_val will be a mortal sv for MAGICAL hashes */
400 =for apidoc hv_fetch_ent
402 Returns the hash entry which corresponds to the specified key in the hash.
403 C<hash> must be a valid precomputed hash number for the given C<key>, or 0
404 if you want the function to compute it. IF C<lval> is set then the fetch
405 will be part of a store. Make sure the return value is non-null before
406 accessing it. The return value when C<tb> is a tied hash is a pointer to a
407 static location, so be sure to make a copy of the structure if you need to
410 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
411 information on how to use this function on tied hashes.
417 Perl_hv_fetch_ent(pTHX_ HV *hv, SV *keysv, I32 lval, register U32 hash)
419 return hv_fetch_common(hv, keysv, NULL, 0, 0,
420 (lval ? HV_FETCH_LVALUE : 0), Nullsv, hash);
424 S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
425 int flags, int action, SV *val, register U32 hash)
439 if (flags & HVhek_FREEKEY)
441 key = SvPV_const(keysv, klen);
443 is_utf8 = (SvUTF8(keysv) != 0);
445 is_utf8 = ((flags & HVhek_UTF8) ? TRUE : FALSE);
448 xhv = (XPVHV*)SvANY(hv);
450 if (SvRMAGICAL(hv) && !(action & (HV_FETCH_ISSTORE|HV_FETCH_ISEXISTS)))
452 if (mg_find((SV*)hv, PERL_MAGIC_tied) || SvGMAGICAL((SV*)hv)) {
455 /* XXX should be able to skimp on the HE/HEK here when
456 HV_FETCH_JUST_SV is true. */
459 keysv = newSVpvn(key, klen);
464 keysv = newSVsv(keysv);
466 mg_copy((SV*)hv, sv, (char *)keysv, HEf_SVKEY);
468 /* grab a fake HE/HEK pair from the pool or make a new one */
469 entry = PL_hv_fetch_ent_mh;
471 PL_hv_fetch_ent_mh = HeNEXT(entry);
475 Newx(k, HEK_BASESIZE + sizeof(SV*), char);
476 HeKEY_hek(entry) = (HEK*)k;
478 HeNEXT(entry) = Nullhe;
479 HeSVKEY_set(entry, keysv);
481 sv_upgrade(sv, SVt_PVLV);
483 /* so we can free entry when freeing sv */
484 LvTARG(sv) = (SV*)entry;
486 /* XXX remove at some point? */
487 if (flags & HVhek_FREEKEY)
492 #ifdef ENV_IS_CASELESS
493 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
495 for (i = 0; i < klen; ++i)
496 if (isLOWER(key[i])) {
497 /* Would be nice if we had a routine to do the
498 copy and upercase in a single pass through. */
499 const char * const nkey = strupr(savepvn(key,klen));
500 /* Note that this fetch is for nkey (the uppercased
501 key) whereas the store is for key (the original) */
502 entry = hv_fetch_common(hv, Nullsv, nkey, klen,
503 HVhek_FREEKEY, /* free nkey */
504 0 /* non-LVAL fetch */,
505 Nullsv /* no value */,
506 0 /* compute hash */);
507 if (!entry && (action & HV_FETCH_LVALUE)) {
508 /* This call will free key if necessary.
509 Do it this way to encourage compiler to tail
511 entry = hv_fetch_common(hv, keysv, key, klen,
512 flags, HV_FETCH_ISSTORE,
515 if (flags & HVhek_FREEKEY)
523 else if (SvRMAGICAL(hv) && (action & HV_FETCH_ISEXISTS)) {
524 if (mg_find((SV*)hv, PERL_MAGIC_tied) || SvGMAGICAL((SV*)hv)) {
525 /* I don't understand why hv_exists_ent has svret and sv,
526 whereas hv_exists only had one. */
527 SV * const svret = sv_newmortal();
530 if (keysv || is_utf8) {
532 keysv = newSVpvn(key, klen);
535 keysv = newSVsv(keysv);
537 mg_copy((SV*)hv, sv, (char *)sv_2mortal(keysv), HEf_SVKEY);
539 mg_copy((SV*)hv, sv, key, klen);
541 if (flags & HVhek_FREEKEY)
543 magic_existspack(svret, mg_find(sv, PERL_MAGIC_tiedelem));
544 /* This cast somewhat evil, but I'm merely using NULL/
545 not NULL to return the boolean exists.
546 And I know hv is not NULL. */
547 return SvTRUE(svret) ? (HE *)hv : NULL;
549 #ifdef ENV_IS_CASELESS
550 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
551 /* XXX This code isn't UTF8 clean. */
552 char * const keysave = (char * const)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;
567 else if (action & HV_FETCH_ISSTORE) {
570 hv_magic_check (hv, &needs_copy, &needs_store);
572 const bool save_taint = PL_tainted;
573 if (keysv || is_utf8) {
575 keysv = newSVpvn(key, klen);
579 PL_tainted = SvTAINTED(keysv);
580 keysv = sv_2mortal(newSVsv(keysv));
581 mg_copy((SV*)hv, val, (char*)keysv, HEf_SVKEY);
583 mg_copy((SV*)hv, val, key, klen);
586 TAINT_IF(save_taint);
587 if (!HvARRAY(hv) && !needs_store) {
588 if (flags & HVhek_FREEKEY)
592 #ifdef ENV_IS_CASELESS
593 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
594 /* XXX This code isn't UTF8 clean. */
595 const char *keysave = key;
596 /* Will need to free this, so set FREEKEY flag. */
597 key = savepvn(key,klen);
598 key = (const char*)strupr((char*)key);
603 if (flags & HVhek_FREEKEY) {
606 flags |= HVhek_FREEKEY;
614 if ((action & (HV_FETCH_LVALUE | HV_FETCH_ISSTORE))
615 #ifdef DYNAMIC_ENV_FETCH /* if it's an %ENV lookup, we may get it on the fly */
616 || (SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env))
621 PERL_HV_ARRAY_ALLOC_BYTES(xhv->xhv_max+1 /* HvMAX(hv)+1 */),
623 HvARRAY(hv) = (HE**)array;
625 #ifdef DYNAMIC_ENV_FETCH
626 else if (action & HV_FETCH_ISEXISTS) {
627 /* for an %ENV exists, if we do an insert it's by a recursive
628 store call, so avoid creating HvARRAY(hv) right now. */
632 /* XXX remove at some point? */
633 if (flags & HVhek_FREEKEY)
641 char * const keysave = (char * const)key;
642 key = (char*)bytes_from_utf8((U8*)key, &klen, &is_utf8);
646 flags &= ~HVhek_UTF8;
647 if (key != keysave) {
648 if (flags & HVhek_FREEKEY)
650 flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
655 PERL_HASH_INTERNAL(hash, key, klen);
656 /* We don't have a pointer to the hv, so we have to replicate the
657 flag into every HEK, so that hv_iterkeysv can see it. */
658 /* And yes, you do need this even though you are not "storing" because
659 you can flip the flags below if doing an lval lookup. (And that
660 was put in to give the semantics Andreas was expecting.) */
661 flags |= HVhek_REHASH;
663 if (keysv && (SvIsCOW_shared_hash(keysv))) {
664 hash = SvSHARED_HASH(keysv);
666 PERL_HASH(hash, key, klen);
670 masked_flags = (flags & HVhek_MASK);
672 #ifdef DYNAMIC_ENV_FETCH
673 if (!HvARRAY(hv)) entry = Null(HE*);
677 entry = (HvARRAY(hv))[hash & (I32) HvMAX(hv)];
679 for (; entry; entry = HeNEXT(entry)) {
680 if (HeHASH(entry) != hash) /* strings can't be equal */
682 if (HeKLEN(entry) != (I32)klen)
684 if (HeKEY(entry) != key && memNE(HeKEY(entry),key,klen)) /* is this it? */
686 if ((HeKFLAGS(entry) ^ masked_flags) & HVhek_UTF8)
689 if (action & (HV_FETCH_LVALUE|HV_FETCH_ISSTORE)) {
690 if (HeKFLAGS(entry) != masked_flags) {
691 /* We match if HVhek_UTF8 bit in our flags and hash key's
692 match. But if entry was set previously with HVhek_WASUTF8
693 and key now doesn't (or vice versa) then we should change
694 the key's flag, as this is assignment. */
695 if (HvSHAREKEYS(hv)) {
696 /* Need to swap the key we have for a key with the flags we
697 need. As keys are shared we can't just write to the
698 flag, so we share the new one, unshare the old one. */
699 HEK *new_hek = share_hek_flags(key, klen, hash,
701 unshare_hek (HeKEY_hek(entry));
702 HeKEY_hek(entry) = new_hek;
704 else if (hv == PL_strtab) {
705 /* PL_strtab is usually the only hash without HvSHAREKEYS,
706 so putting this test here is cheap */
707 if (flags & HVhek_FREEKEY)
709 Perl_croak(aTHX_ S_strtab_error,
710 action & HV_FETCH_LVALUE ? "fetch" : "store");
713 HeKFLAGS(entry) = masked_flags;
714 if (masked_flags & HVhek_ENABLEHVKFLAGS)
717 if (HeVAL(entry) == &PL_sv_placeholder) {
718 /* yes, can store into placeholder slot */
719 if (action & HV_FETCH_LVALUE) {
721 /* This preserves behaviour with the old hv_fetch
722 implementation which at this point would bail out
723 with a break; (at "if we find a placeholder, we
724 pretend we haven't found anything")
726 That break mean that if a placeholder were found, it
727 caused a call into hv_store, which in turn would
728 check magic, and if there is no magic end up pretty
729 much back at this point (in hv_store's code). */
732 /* LVAL fetch which actaully needs a store. */
734 HvPLACEHOLDERS(hv)--;
737 if (val != &PL_sv_placeholder)
738 HvPLACEHOLDERS(hv)--;
741 } else if (action & HV_FETCH_ISSTORE) {
742 SvREFCNT_dec(HeVAL(entry));
745 } else if (HeVAL(entry) == &PL_sv_placeholder) {
746 /* if we find a placeholder, we pretend we haven't found
750 if (flags & HVhek_FREEKEY)
754 #ifdef DYNAMIC_ENV_FETCH /* %ENV lookup? If so, try to fetch the value now */
755 if (!(action & HV_FETCH_ISSTORE)
756 && SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env)) {
758 const char * const env = PerlEnv_ENVgetenv_len(key,&len);
760 sv = newSVpvn(env,len);
762 return hv_fetch_common(hv,keysv,key,klen,flags,HV_FETCH_ISSTORE,sv,
768 if (!entry && SvREADONLY(hv) && !(action & HV_FETCH_ISEXISTS)) {
769 hv_notallowed(flags, key, klen,
770 "Attempt to access disallowed key '%"SVf"' in"
771 " a restricted hash");
773 if (!(action & (HV_FETCH_LVALUE|HV_FETCH_ISSTORE))) {
774 /* Not doing some form of store, so return failure. */
775 if (flags & HVhek_FREEKEY)
779 if (action & HV_FETCH_LVALUE) {
782 /* At this point the old hv_fetch code would call to hv_store,
783 which in turn might do some tied magic. So we need to make that
784 magic check happen. */
785 /* gonna assign to this, so it better be there */
786 return hv_fetch_common(hv, keysv, key, klen, flags,
787 HV_FETCH_ISSTORE, val, hash);
788 /* XXX Surely that could leak if the fetch-was-store fails?
789 Just like the hv_fetch. */
793 /* Welcome to hv_store... */
796 /* Not sure if we can get here. I think the only case of oentry being
797 NULL is for %ENV with dynamic env fetch. But that should disappear
798 with magic in the previous code. */
801 PERL_HV_ARRAY_ALLOC_BYTES(xhv->xhv_max+1 /* HvMAX(hv)+1 */),
803 HvARRAY(hv) = (HE**)array;
806 oentry = &(HvARRAY(hv))[hash & (I32) xhv->xhv_max];
809 /* share_hek_flags will do the free for us. This might be considered
812 HeKEY_hek(entry) = share_hek_flags(key, klen, hash, flags);
813 else if (hv == PL_strtab) {
814 /* PL_strtab is usually the only hash without HvSHAREKEYS, so putting
815 this test here is cheap */
816 if (flags & HVhek_FREEKEY)
818 Perl_croak(aTHX_ S_strtab_error,
819 action & HV_FETCH_LVALUE ? "fetch" : "store");
821 else /* gotta do the real thing */
822 HeKEY_hek(entry) = save_hek_flags(key, klen, hash, flags);
824 HeNEXT(entry) = *oentry;
827 if (val == &PL_sv_placeholder)
828 HvPLACEHOLDERS(hv)++;
829 if (masked_flags & HVhek_ENABLEHVKFLAGS)
833 const HE *counter = HeNEXT(entry);
835 xhv->xhv_keys++; /* HvKEYS(hv)++ */
836 if (!counter) { /* initial entry? */
837 xhv->xhv_fill++; /* HvFILL(hv)++ */
838 } else if (xhv->xhv_keys > (IV)xhv->xhv_max) {
840 } else if(!HvREHASH(hv)) {
843 while ((counter = HeNEXT(counter)))
846 if (n_links > HV_MAX_LENGTH_BEFORE_SPLIT) {
847 /* Use only the old HvKEYS(hv) > HvMAX(hv) condition to limit
848 bucket splits on a rehashed hash, as we're not going to
849 split it again, and if someone is lucky (evil) enough to
850 get all the keys in one list they could exhaust our memory
851 as we repeatedly double the number of buckets on every
852 entry. Linear search feels a less worse thing to do. */
862 S_hv_magic_check(pTHX_ HV *hv, bool *needs_copy, bool *needs_store)
864 const MAGIC *mg = SvMAGIC(hv);
868 if (isUPPER(mg->mg_type)) {
870 if (mg->mg_type == PERL_MAGIC_tied) {
871 *needs_store = FALSE;
872 return; /* We've set all there is to set. */
875 mg = mg->mg_moremagic;
880 =for apidoc hv_scalar
882 Evaluates the hash in scalar context and returns the result. Handles magic when the hash is tied.
888 Perl_hv_scalar(pTHX_ HV *hv)
892 if (SvRMAGICAL(hv)) {
893 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_tied);
895 return magic_scalarpack(hv, mg);
900 Perl_sv_setpvf(aTHX_ sv, "%ld/%ld",
901 (long)HvFILL(hv), (long)HvMAX(hv) + 1);
909 =for apidoc hv_delete
911 Deletes a key/value pair in the hash. The value SV is removed from the
912 hash and returned to the caller. The C<klen> is the length of the key.
913 The C<flags> value will normally be zero; if set to G_DISCARD then NULL
920 Perl_hv_delete(pTHX_ HV *hv, const char *key, I32 klen_i32, I32 flags)
927 k_flags |= HVhek_UTF8;
931 return hv_delete_common(hv, NULL, key, klen, k_flags, flags, 0);
935 =for apidoc hv_delete_ent
937 Deletes a key/value pair in the hash. The value SV is removed from the
938 hash and returned to the caller. The C<flags> value will normally be zero;
939 if set to G_DISCARD then NULL will be returned. C<hash> can be a valid
940 precomputed hash value, or 0 to ask for it to be computed.
945 /* XXX This looks like an ideal candidate to inline */
947 Perl_hv_delete_ent(pTHX_ HV *hv, SV *keysv, I32 flags, U32 hash)
949 return hv_delete_common(hv, keysv, NULL, 0, 0, flags, hash);
953 S_hv_delete_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
954 int k_flags, I32 d_flags, U32 hash)
959 register HE **oentry;
960 HE *const *first_entry;
969 if (k_flags & HVhek_FREEKEY)
971 key = SvPV_const(keysv, klen);
973 is_utf8 = (SvUTF8(keysv) != 0);
975 is_utf8 = ((k_flags & HVhek_UTF8) ? TRUE : FALSE);
978 if (SvRMAGICAL(hv)) {
981 hv_magic_check (hv, &needs_copy, &needs_store);
984 entry = hv_fetch_common(hv, keysv, key, klen,
985 k_flags & ~HVhek_FREEKEY, HV_FETCH_LVALUE,
987 sv = entry ? HeVAL(entry) : NULL;
993 if (mg_find(sv, PERL_MAGIC_tiedelem)) {
994 /* No longer an element */
995 sv_unmagic(sv, PERL_MAGIC_tiedelem);
998 return Nullsv; /* element cannot be deleted */
1000 #ifdef ENV_IS_CASELESS
1001 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
1002 /* XXX This code isn't UTF8 clean. */
1003 keysv = sv_2mortal(newSVpvn(key,klen));
1004 if (k_flags & HVhek_FREEKEY) {
1007 key = strupr(SvPVX(keysv));
1016 xhv = (XPVHV*)SvANY(hv);
1021 const char * const keysave = key;
1022 key = (char*)bytes_from_utf8((U8*)key, &klen, &is_utf8);
1025 k_flags |= HVhek_UTF8;
1027 k_flags &= ~HVhek_UTF8;
1028 if (key != keysave) {
1029 if (k_flags & HVhek_FREEKEY) {
1030 /* This shouldn't happen if our caller does what we expect,
1031 but strictly the API allows it. */
1034 k_flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
1036 HvHASKFLAGS_on((SV*)hv);
1040 PERL_HASH_INTERNAL(hash, key, klen);
1042 if (keysv && (SvIsCOW_shared_hash(keysv))) {
1043 hash = SvSHARED_HASH(keysv);
1045 PERL_HASH(hash, key, klen);
1049 masked_flags = (k_flags & HVhek_MASK);
1051 first_entry = oentry = &(HvARRAY(hv))[hash & (I32) HvMAX(hv)];
1053 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)
1072 if (k_flags & HVhek_FREEKEY)
1076 else if (SvREADONLY(hv) && HeVAL(entry) && SvREADONLY(HeVAL(entry))) {
1077 S_hv_notallowed(aTHX_ k_flags, key, klen,
1078 "Attempt to delete readonly key '%"SVf"' from"
1079 " a restricted hash");
1081 if (k_flags & HVhek_FREEKEY)
1084 if (d_flags & G_DISCARD)
1087 sv = sv_2mortal(HeVAL(entry));
1088 HeVAL(entry) = &PL_sv_placeholder;
1092 * If a restricted hash, rather than really deleting the entry, put
1093 * a placeholder there. This marks the key as being "approved", so
1094 * we can still access via not-really-existing key without raising
1097 if (SvREADONLY(hv)) {
1098 SvREFCNT_dec(HeVAL(entry));
1099 HeVAL(entry) = &PL_sv_placeholder;
1100 /* We'll be saving this slot, so the number of allocated keys
1101 * doesn't go down, but the number placeholders goes up */
1102 HvPLACEHOLDERS(hv)++;
1104 *oentry = HeNEXT(entry);
1106 xhv->xhv_fill--; /* HvFILL(hv)-- */
1108 if (SvOOK(hv) && entry == HvAUX(hv)->xhv_eiter /* HvEITER(hv) */)
1111 hv_free_ent(hv, entry);
1112 xhv->xhv_keys--; /* HvKEYS(hv)-- */
1113 if (xhv->xhv_keys == 0)
1114 HvHASKFLAGS_off(hv);
1118 if (SvREADONLY(hv)) {
1119 S_hv_notallowed(aTHX_ k_flags, key, klen,
1120 "Attempt to delete disallowed key '%"SVf"' from"
1121 " a restricted hash");
1124 if (k_flags & HVhek_FREEKEY)
1130 S_hsplit(pTHX_ HV *hv)
1133 register XPVHV* xhv = (XPVHV*)SvANY(hv);
1134 const I32 oldsize = (I32) xhv->xhv_max+1; /* HvMAX(hv)+1 (sick) */
1135 register I32 newsize = oldsize * 2;
1137 char *a = (char*) HvARRAY(hv);
1139 register HE **oentry;
1140 int longest_chain = 0;
1143 /*PerlIO_printf(PerlIO_stderr(), "hsplit called for %p which had %d\n",
1144 hv, (int) oldsize);*/
1146 if (HvPLACEHOLDERS_get(hv) && !SvREADONLY(hv)) {
1147 /* Can make this clear any placeholders first for non-restricted hashes,
1148 even though Storable rebuilds restricted hashes by putting in all the
1149 placeholders (first) before turning on the readonly flag, because
1150 Storable always pre-splits the hash. */
1151 hv_clear_placeholders(hv);
1155 #if defined(STRANGE_MALLOC) || defined(MYMALLOC)
1156 Renew(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1157 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1163 Copy(&a[oldsize * sizeof(HE*)], &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1166 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1167 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1172 Copy(HvARRAY(hv), a, oldsize * sizeof(HE*), char);
1174 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1176 if (oldsize >= 64) {
1177 offer_nice_chunk(HvARRAY(hv),
1178 PERL_HV_ARRAY_ALLOC_BYTES(oldsize)
1179 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0));
1182 Safefree(HvARRAY(hv));
1186 Zero(&a[oldsize * sizeof(HE*)], (newsize-oldsize) * sizeof(HE*), char); /* zero 2nd half*/
1187 xhv->xhv_max = --newsize; /* HvMAX(hv) = --newsize */
1188 HvARRAY(hv) = (HE**) a;
1191 for (i=0; i<oldsize; i++,aep++) {
1192 int left_length = 0;
1193 int right_length = 0;
1197 if (!*aep) /* non-existent */
1200 for (oentry = aep, entry = *aep; entry; entry = *oentry) {
1201 if ((HeHASH(entry) & newsize) != (U32)i) {
1202 *oentry = HeNEXT(entry);
1203 HeNEXT(entry) = *bep;
1205 xhv->xhv_fill++; /* HvFILL(hv)++ */
1211 oentry = &HeNEXT(entry);
1215 if (!*aep) /* everything moved */
1216 xhv->xhv_fill--; /* HvFILL(hv)-- */
1217 /* I think we don't actually need to keep track of the longest length,
1218 merely flag if anything is too long. But for the moment while
1219 developing this code I'll track it. */
1220 if (left_length > longest_chain)
1221 longest_chain = left_length;
1222 if (right_length > longest_chain)
1223 longest_chain = right_length;
1227 /* Pick your policy for "hashing isn't working" here: */
1228 if (longest_chain <= HV_MAX_LENGTH_BEFORE_SPLIT /* split worked? */
1233 if (hv == PL_strtab) {
1234 /* Urg. Someone is doing something nasty to the string table.
1239 /* Awooga. Awooga. Pathological data. */
1240 /*PerlIO_printf(PerlIO_stderr(), "%p %d of %d with %d/%d buckets\n", hv,
1241 longest_chain, HvTOTALKEYS(hv), HvFILL(hv), 1+HvMAX(hv));*/
1244 Newxz(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1245 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1247 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1250 was_shared = HvSHAREKEYS(hv);
1253 HvSHAREKEYS_off(hv);
1258 for (i=0; i<newsize; i++,aep++) {
1259 register HE *entry = *aep;
1261 /* We're going to trash this HE's next pointer when we chain it
1262 into the new hash below, so store where we go next. */
1263 HE * const next = HeNEXT(entry);
1268 PERL_HASH_INTERNAL(hash, HeKEY(entry), HeKLEN(entry));
1273 = save_hek_flags(HeKEY(entry), HeKLEN(entry),
1274 hash, HeKFLAGS(entry));
1275 unshare_hek (HeKEY_hek(entry));
1276 HeKEY_hek(entry) = new_hek;
1278 /* Not shared, so simply write the new hash in. */
1279 HeHASH(entry) = hash;
1281 /*PerlIO_printf(PerlIO_stderr(), "%d ", HeKFLAGS(entry));*/
1282 HEK_REHASH_on(HeKEY_hek(entry));
1283 /*PerlIO_printf(PerlIO_stderr(), "%d\n", HeKFLAGS(entry));*/
1285 /* Copy oentry to the correct new chain. */
1286 bep = ((HE**)a) + (hash & (I32) xhv->xhv_max);
1288 xhv->xhv_fill++; /* HvFILL(hv)++ */
1289 HeNEXT(entry) = *bep;
1295 Safefree (HvARRAY(hv));
1296 HvARRAY(hv) = (HE **)a;
1300 Perl_hv_ksplit(pTHX_ HV *hv, IV newmax)
1303 register XPVHV* xhv = (XPVHV*)SvANY(hv);
1304 const I32 oldsize = (I32) xhv->xhv_max+1; /* HvMAX(hv)+1 (sick) */
1305 register I32 newsize;
1310 register HE **oentry;
1312 newsize = (I32) newmax; /* possible truncation here */
1313 if (newsize != newmax || newmax <= oldsize)
1315 while ((newsize & (1 + ~newsize)) != newsize) {
1316 newsize &= ~(newsize & (1 + ~newsize)); /* get proper power of 2 */
1318 if (newsize < newmax)
1320 if (newsize < newmax)
1321 return; /* overflow detection */
1323 a = (char *) HvARRAY(hv);
1326 #if defined(STRANGE_MALLOC) || defined(MYMALLOC)
1327 Renew(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1328 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1334 Copy(&a[oldsize * sizeof(HE*)], &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1337 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1338 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1343 Copy(HvARRAY(hv), a, oldsize * sizeof(HE*), char);
1345 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1347 if (oldsize >= 64) {
1348 offer_nice_chunk(HvARRAY(hv),
1349 PERL_HV_ARRAY_ALLOC_BYTES(oldsize)
1350 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0));
1353 Safefree(HvARRAY(hv));
1356 Zero(&a[oldsize * sizeof(HE*)], (newsize-oldsize) * sizeof(HE*), char); /* zero 2nd half*/
1359 Newxz(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize), char);
1361 xhv->xhv_max = --newsize; /* HvMAX(hv) = --newsize */
1362 HvARRAY(hv) = (HE **) a;
1363 if (!xhv->xhv_fill /* !HvFILL(hv) */) /* skip rest if no entries */
1367 for (i=0; i<oldsize; i++,aep++) {
1368 if (!*aep) /* non-existent */
1370 for (oentry = aep, entry = *aep; entry; entry = *oentry) {
1372 if ((j = (HeHASH(entry) & newsize)) != i) {
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(502,0);
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++) {
1436 HE *prev = NULL, *ent = NULL;
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);
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* 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 **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, Nullch, 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(pTHX_ 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 *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*) */
1878 S_hv_auxinit(aTHX_ hv);
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) : S_hv_auxinit(aTHX_ 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) : S_hv_auxinit(aTHX_ 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 = S_hv_auxinit(aTHX_ 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 = S_hv_auxinit(aTHX_ 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 = S_hv_auxinit(aTHX_ 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 *iter;
1973 iter = SvOOK(hv) ? HvAUX(hv) : S_hv_auxinit(aTHX_ hv);
1974 return &(iter->xhv_backreferences);
1978 Perl_hv_kill_backrefs(pTHX_ HV *hv) {
1984 av = HvAUX(hv)->xhv_backreferences;
1987 HvAUX(hv)->xhv_backreferences = 0;
1988 Perl_sv_kill_backrefs(aTHX_ (SV*) hv, av);
1993 hv_iternext is implemented as a macro in hv.h
1995 =for apidoc hv_iternext
1997 Returns entries from a hash iterator. See C<hv_iterinit>.
1999 You may call C<hv_delete> or C<hv_delete_ent> on the hash entry that the
2000 iterator currently points to, without losing your place or invalidating your
2001 iterator. Note that in this case the current entry is deleted from the hash
2002 with your iterator holding the last reference to it. Your iterator is flagged
2003 to free the entry on the next call to C<hv_iternext>, so you must not discard
2004 your iterator immediately else the entry will leak - call C<hv_iternext> to
2005 trigger the resource deallocation.
2007 =for apidoc hv_iternext_flags
2009 Returns entries from a hash iterator. See C<hv_iterinit> and C<hv_iternext>.
2010 The C<flags> value will normally be zero; if HV_ITERNEXT_WANTPLACEHOLDERS is
2011 set the placeholders keys (for restricted hashes) will be returned in addition
2012 to normal keys. By default placeholders are automatically skipped over.
2013 Currently a placeholder is implemented with a value that is
2014 C<&Perl_sv_placeholder>. Note that the implementation of placeholders and
2015 restricted hashes may change, and the implementation currently is
2016 insufficiently abstracted for any change to be tidy.
2022 Perl_hv_iternext_flags(pTHX_ HV *hv, I32 flags)
2025 register XPVHV* xhv;
2029 struct xpvhv_aux *iter;
2032 Perl_croak(aTHX_ "Bad hash");
2033 xhv = (XPVHV*)SvANY(hv);
2036 /* Too many things (well, pp_each at least) merrily assume that you can
2037 call iv_iternext without calling hv_iterinit, so we'll have to deal
2043 oldentry = entry = iter->xhv_eiter; /* HvEITER(hv) */
2045 if ((mg = SvTIED_mg((SV*)hv, PERL_MAGIC_tied))) {
2046 SV * const key = sv_newmortal();
2048 sv_setsv(key, HeSVKEY_force(entry));
2049 SvREFCNT_dec(HeSVKEY(entry)); /* get rid of previous key */
2055 /* one HE per MAGICAL hash */
2056 iter->xhv_eiter = entry = new_HE(); /* HvEITER(hv) = new_HE() */
2058 Newxz(k, HEK_BASESIZE + sizeof(SV*), char);
2060 HeKEY_hek(entry) = hek;
2061 HeKLEN(entry) = HEf_SVKEY;
2063 magic_nextpack((SV*) hv,mg,key);
2065 /* force key to stay around until next time */
2066 HeSVKEY_set(entry, SvREFCNT_inc(key));
2067 return entry; /* beware, hent_val is not set */
2070 SvREFCNT_dec(HeVAL(entry));
2071 Safefree(HeKEY_hek(entry));
2073 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
2076 #ifdef DYNAMIC_ENV_FETCH /* set up %ENV for iteration */
2077 if (!entry && SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env)) {
2080 /* The prime_env_iter() on VMS just loaded up new hash values
2081 * so the iteration count needs to be reset back to the beginning
2085 oldentry = entry = iter->xhv_eiter; /* HvEITER(hv) */
2090 /* hv_iterint now ensures this. */
2091 assert (HvARRAY(hv));
2093 /* At start of hash, entry is NULL. */
2096 entry = HeNEXT(entry);
2097 if (!(flags & HV_ITERNEXT_WANTPLACEHOLDERS)) {
2099 * Skip past any placeholders -- don't want to include them in
2102 while (entry && HeVAL(entry) == &PL_sv_placeholder) {
2103 entry = HeNEXT(entry);
2108 /* OK. Come to the end of the current list. Grab the next one. */
2110 iter->xhv_riter++; /* HvRITER(hv)++ */
2111 if (iter->xhv_riter > (I32)xhv->xhv_max /* HvRITER(hv) > HvMAX(hv) */) {
2112 /* There is no next one. End of the hash. */
2113 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
2116 entry = (HvARRAY(hv))[iter->xhv_riter];
2118 if (!(flags & HV_ITERNEXT_WANTPLACEHOLDERS)) {
2119 /* If we have an entry, but it's a placeholder, don't count it.
2121 while (entry && HeVAL(entry) == &PL_sv_placeholder)
2122 entry = HeNEXT(entry);
2124 /* Will loop again if this linked list starts NULL
2125 (for HV_ITERNEXT_WANTPLACEHOLDERS)
2126 or if we run through it and find only placeholders. */
2129 if (oldentry && HvLAZYDEL(hv)) { /* was deleted earlier? */
2131 hv_free_ent(hv, oldentry);
2134 /*if (HvREHASH(hv) && entry && !HeKREHASH(entry))
2135 PerlIO_printf(PerlIO_stderr(), "Awooga %p %p\n", hv, entry);*/
2137 iter->xhv_eiter = entry; /* HvEITER(hv) = entry */
2142 =for apidoc hv_iterkey
2144 Returns the key from the current position of the hash iterator. See
2151 Perl_hv_iterkey(pTHX_ register HE *entry, I32 *retlen)
2153 if (HeKLEN(entry) == HEf_SVKEY) {
2155 char * const p = SvPV(HeKEY_sv(entry), len);
2160 *retlen = HeKLEN(entry);
2161 return HeKEY(entry);
2165 /* unlike hv_iterval(), this always returns a mortal copy of the key */
2167 =for apidoc hv_iterkeysv
2169 Returns the key as an C<SV*> from the current position of the hash
2170 iterator. The return value will always be a mortal copy of the key. Also
2177 Perl_hv_iterkeysv(pTHX_ register HE *entry)
2179 return sv_2mortal(newSVhek(HeKEY_hek(entry)));
2183 =for apidoc hv_iterval
2185 Returns the value from the current position of the hash iterator. See
2192 Perl_hv_iterval(pTHX_ HV *hv, register HE *entry)
2194 if (SvRMAGICAL(hv)) {
2195 if (mg_find((SV*)hv, PERL_MAGIC_tied)) {
2196 SV* const sv = sv_newmortal();
2197 if (HeKLEN(entry) == HEf_SVKEY)
2198 mg_copy((SV*)hv, sv, (char*)HeKEY_sv(entry), HEf_SVKEY);
2200 mg_copy((SV*)hv, sv, HeKEY(entry), HeKLEN(entry));
2204 return HeVAL(entry);
2208 =for apidoc hv_iternextsv
2210 Performs an C<hv_iternext>, C<hv_iterkey>, and C<hv_iterval> in one
2217 Perl_hv_iternextsv(pTHX_ HV *hv, char **key, I32 *retlen)
2219 HE * const he = hv_iternext_flags(hv, 0);
2223 *key = hv_iterkey(he, retlen);
2224 return hv_iterval(hv, he);
2231 =for apidoc hv_magic
2233 Adds magic to a hash. See C<sv_magic>.
2238 /* possibly free a shared string if no one has access to it
2239 * len and hash must both be valid for str.
2242 Perl_unsharepvn(pTHX_ const char *str, I32 len, U32 hash)
2244 unshare_hek_or_pvn (NULL, str, len, hash);
2249 Perl_unshare_hek(pTHX_ HEK *hek)
2251 unshare_hek_or_pvn(hek, NULL, 0, 0);
2254 /* possibly free a shared string if no one has access to it
2255 hek if non-NULL takes priority over the other 3, else str, len and hash
2256 are used. If so, len and hash must both be valid for str.
2259 S_unshare_hek_or_pvn(pTHX_ const HEK *hek, const char *str, I32 len, U32 hash)
2262 register XPVHV* xhv;
2264 register HE **oentry;
2267 bool is_utf8 = FALSE;
2269 const char * const save = str;
2270 struct shared_he *he = NULL;
2273 /* Find the shared he which is just before us in memory. */
2274 he = (struct shared_he *)(((char *)hek)
2275 - STRUCT_OFFSET(struct shared_he,
2278 /* Assert that the caller passed us a genuine (or at least consistent)
2280 assert (he->shared_he_he.hent_hek == hek);
2283 if (he->shared_he_he.hent_val - 1) {
2284 --he->shared_he_he.hent_val;
2285 UNLOCK_STRTAB_MUTEX;
2288 UNLOCK_STRTAB_MUTEX;
2290 hash = HEK_HASH(hek);
2291 } else if (len < 0) {
2292 STRLEN tmplen = -len;
2294 /* See the note in hv_fetch(). --jhi */
2295 str = (char*)bytes_from_utf8((U8*)str, &tmplen, &is_utf8);
2298 k_flags = HVhek_UTF8;
2300 k_flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
2303 /* what follows is the moral equivalent of:
2304 if ((Svp = hv_fetch(PL_strtab, tmpsv, FALSE, hash))) {
2305 if (--*Svp == Nullsv)
2306 hv_delete(PL_strtab, str, len, G_DISCARD, hash);
2308 xhv = (XPVHV*)SvANY(PL_strtab);
2309 /* assert(xhv_array != 0) */
2311 first = oentry = &(HvARRAY(PL_strtab))[hash & (I32) HvMAX(PL_strtab)];
2313 const HE *const he_he = &(he->shared_he_he);
2314 for (entry = *oentry; entry; oentry = &HeNEXT(entry), entry = *oentry) {
2321 const int flags_masked = k_flags & HVhek_MASK;
2322 for (entry = *oentry; entry; oentry = &HeNEXT(entry), entry = *oentry) {
2323 if (HeHASH(entry) != hash) /* strings can't be equal */
2325 if (HeKLEN(entry) != len)
2327 if (HeKEY(entry) != str && memNE(HeKEY(entry),str,len)) /* is this it? */
2329 if (HeKFLAGS(entry) != flags_masked)
2337 if (--HeVAL(entry) == Nullsv) {
2338 *oentry = HeNEXT(entry);
2340 /* There are now no entries in our slot. */
2341 xhv->xhv_fill--; /* HvFILL(hv)-- */
2344 xhv->xhv_keys--; /* HvKEYS(hv)-- */
2348 UNLOCK_STRTAB_MUTEX;
2349 if (!found && ckWARN_d(WARN_INTERNAL))
2350 Perl_warner(aTHX_ packWARN(WARN_INTERNAL),
2351 "Attempt to free non-existent shared string '%s'%s"
2353 hek ? HEK_KEY(hek) : str,
2354 ((k_flags & HVhek_UTF8) ? " (utf8)" : "") pTHX__VALUE);
2355 if (k_flags & HVhek_FREEKEY)
2359 /* get a (constant) string ptr from the global string table
2360 * string will get added if it is not already there.
2361 * len and hash must both be valid for str.
2364 Perl_share_hek(pTHX_ const char *str, I32 len, register U32 hash)
2366 bool is_utf8 = FALSE;
2368 const char * const save = str;
2371 STRLEN tmplen = -len;
2373 /* See the note in hv_fetch(). --jhi */
2374 str = (char*)bytes_from_utf8((U8*)str, &tmplen, &is_utf8);
2376 /* If we were able to downgrade here, then than means that we were passed
2377 in a key which only had chars 0-255, but was utf8 encoded. */
2380 /* If we found we were able to downgrade the string to bytes, then
2381 we should flag that it needs upgrading on keys or each. Also flag
2382 that we need share_hek_flags to free the string. */
2384 flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
2387 return share_hek_flags (str, len, hash, flags);
2391 S_share_hek_flags(pTHX_ const char *str, I32 len, register U32 hash, int flags)
2395 const int flags_masked = flags & HVhek_MASK;
2396 const U32 hindex = hash & (I32) HvMAX(PL_strtab);
2398 /* what follows is the moral equivalent of:
2400 if (!(Svp = hv_fetch(PL_strtab, str, len, FALSE)))
2401 hv_store(PL_strtab, str, len, Nullsv, hash);
2403 Can't rehash the shared string table, so not sure if it's worth
2404 counting the number of entries in the linked list
2406 register XPVHV * const xhv = (XPVHV*)SvANY(PL_strtab);
2407 /* assert(xhv_array != 0) */
2409 entry = (HvARRAY(PL_strtab))[hindex];
2410 for (;entry; entry = HeNEXT(entry)) {
2411 if (HeHASH(entry) != hash) /* strings can't be equal */
2413 if (HeKLEN(entry) != len)
2415 if (HeKEY(entry) != str && memNE(HeKEY(entry),str,len)) /* is this it? */
2417 if (HeKFLAGS(entry) != flags_masked)
2423 /* What used to be head of the list.
2424 If this is NULL, then we're the first entry for this slot, which
2425 means we need to increate fill. */
2426 struct shared_he *new_entry;
2429 HE **const head = &HvARRAY(PL_strtab)[hindex];
2430 HE *const next = *head;
2432 /* We don't actually store a HE from the arena and a regular HEK.
2433 Instead we allocate one chunk of memory big enough for both,
2434 and put the HEK straight after the HE. This way we can find the
2435 HEK directly from the HE.
2438 Newx(k, STRUCT_OFFSET(struct shared_he,
2439 shared_he_hek.hek_key[0]) + len + 2, char);
2440 new_entry = (struct shared_he *)k;
2441 entry = &(new_entry->shared_he_he);
2442 hek = &(new_entry->shared_he_hek);
2444 Copy(str, HEK_KEY(hek), len, char);
2445 HEK_KEY(hek)[len] = 0;
2447 HEK_HASH(hek) = hash;
2448 HEK_FLAGS(hek) = (unsigned char)flags_masked;
2450 /* Still "point" to the HEK, so that other code need not know what
2452 HeKEY_hek(entry) = hek;
2453 HeVAL(entry) = Nullsv;
2454 HeNEXT(entry) = next;
2457 xhv->xhv_keys++; /* HvKEYS(hv)++ */
2458 if (!next) { /* initial entry? */
2459 xhv->xhv_fill++; /* HvFILL(hv)++ */
2460 } else if (xhv->xhv_keys > (IV)xhv->xhv_max /* HvKEYS(hv) > HvMAX(hv) */) {
2465 ++HeVAL(entry); /* use value slot as REFCNT */
2466 UNLOCK_STRTAB_MUTEX;
2468 if (flags & HVhek_FREEKEY)
2471 return HeKEY_hek(entry);
2475 Perl_hv_placeholders_p(pTHX_ HV *hv)
2478 MAGIC *mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2481 mg = sv_magicext((SV*)hv, 0, PERL_MAGIC_rhash, 0, 0, 0);
2484 Perl_die(aTHX_ "panic: hv_placeholders_p");
2487 return &(mg->mg_len);
2492 Perl_hv_placeholders_get(pTHX_ HV *hv)
2495 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2497 return mg ? mg->mg_len : 0;
2501 Perl_hv_placeholders_set(pTHX_ HV *hv, I32 ph)
2504 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2509 if (!sv_magicext((SV*)hv, 0, PERL_MAGIC_rhash, 0, 0, ph))
2510 Perl_die(aTHX_ "panic: hv_placeholders_set");
2512 /* else we don't need to add magic to record 0 placeholders. */
2516 =for apidoc hv_assert
2518 Check that a hash is in an internally consistent state.
2524 Perl_hv_assert(pTHX_ HV *hv)
2529 int placeholders = 0;
2532 const I32 riter = HvRITER_get(hv);
2533 HE *eiter = HvEITER_get(hv);
2535 (void)hv_iterinit(hv);
2537 while ((entry = hv_iternext_flags(hv, HV_ITERNEXT_WANTPLACEHOLDERS))) {
2538 /* sanity check the values */
2539 if (HeVAL(entry) == &PL_sv_placeholder) {
2544 /* sanity check the keys */
2545 if (HeSVKEY(entry)) {
2546 /* Don't know what to check on SV keys. */
2547 } else if (HeKUTF8(entry)) {
2549 if (HeKWASUTF8(entry)) {
2550 PerlIO_printf(Perl_debug_log,
2551 "hash key has both WASUFT8 and UTF8: '%.*s'\n",
2552 (int) HeKLEN(entry), HeKEY(entry));
2555 } else if (HeKWASUTF8(entry)) {
2559 if (!SvTIED_mg((SV*)hv, PERL_MAGIC_tied)) {
2560 if (HvUSEDKEYS(hv) != real) {
2561 PerlIO_printf(Perl_debug_log, "Count %d key(s), but hash reports %d\n",
2562 (int) real, (int) HvUSEDKEYS(hv));
2565 if (HvPLACEHOLDERS_get(hv) != placeholders) {
2566 PerlIO_printf(Perl_debug_log,
2567 "Count %d placeholder(s), but hash reports %d\n",
2568 (int) placeholders, (int) HvPLACEHOLDERS_get(hv));
2572 if (withflags && ! HvHASKFLAGS(hv)) {
2573 PerlIO_printf(Perl_debug_log,
2574 "Hash has HASKFLAGS off but I count %d key(s) with flags\n",
2581 HvRITER_set(hv, riter); /* Restore hash iterator state */
2582 HvEITER_set(hv, eiter);
2587 * c-indentation-style: bsd
2589 * indent-tabs-mode: t
2592 * ex: set ts=8 sts=4 sw=4 noet: