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);
47 HeNEXT(he) = (HE*) PL_body_arenas;
50 heend = &he[PERL_ARENA_SIZE / sizeof(HE) - 1];
51 PL_body_roots[HE_SVSLOT] = ++he;
53 HeNEXT(he) = (HE*)(he + 1);
61 #define new_HE() (HE*)safemalloc(sizeof(HE))
62 #define del_HE(p) safefree((char*)p)
71 void ** const root = &PL_body_roots[HE_SVSLOT];
82 #define new_HE() new_he()
86 HeNEXT(p) = (HE*)(PL_body_roots[HE_SVSLOT]); \
87 PL_body_roots[HE_SVSLOT] = p; \
96 S_save_hek_flags(pTHX_ const char *str, I32 len, U32 hash, int flags)
98 const int flags_masked = flags & HVhek_MASK;
102 Newx(k, HEK_BASESIZE + len + 2, char);
104 Copy(str, HEK_KEY(hek), len, char);
105 HEK_KEY(hek)[len] = 0;
107 HEK_HASH(hek) = hash;
108 HEK_FLAGS(hek) = (unsigned char)flags_masked;
110 if (flags & HVhek_FREEKEY)
115 /* free the pool of temporary HE/HEK pairs returned by hv_fetch_ent
119 Perl_free_tied_hv_pool(pTHX)
122 HE *he = PL_hv_fetch_ent_mh;
125 Safefree(HeKEY_hek(he));
129 PL_hv_fetch_ent_mh = Nullhe;
132 #if defined(USE_ITHREADS)
134 Perl_hek_dup(pTHX_ HEK *source, CLONE_PARAMS* param)
136 HEK *shared = (HEK*)ptr_table_fetch(PL_ptr_table, source);
138 PERL_UNUSED_ARG(param);
141 /* We already shared this hash key. */
142 (void)share_hek_hek(shared);
146 = share_hek_flags(HEK_KEY(source), HEK_LEN(source),
147 HEK_HASH(source), HEK_FLAGS(source));
148 ptr_table_store(PL_ptr_table, source, shared);
154 Perl_he_dup(pTHX_ const HE *e, bool shared, CLONE_PARAMS* param)
160 /* look for it in the table first */
161 ret = (HE*)ptr_table_fetch(PL_ptr_table, e);
165 /* create anew and remember what it is */
167 ptr_table_store(PL_ptr_table, e, ret);
169 HeNEXT(ret) = he_dup(HeNEXT(e),shared, param);
170 if (HeKLEN(e) == HEf_SVKEY) {
172 Newx(k, HEK_BASESIZE + sizeof(SV*), char);
173 HeKEY_hek(ret) = (HEK*)k;
174 HeKEY_sv(ret) = SvREFCNT_inc(sv_dup(HeKEY_sv(e), param));
177 /* This is hek_dup inlined, which seems to be important for speed
179 HEK * const source = HeKEY_hek(e);
180 HEK *shared = (HEK*)ptr_table_fetch(PL_ptr_table, source);
183 /* We already shared this hash key. */
184 (void)share_hek_hek(shared);
188 = share_hek_flags(HEK_KEY(source), HEK_LEN(source),
189 HEK_HASH(source), HEK_FLAGS(source));
190 ptr_table_store(PL_ptr_table, source, shared);
192 HeKEY_hek(ret) = shared;
195 HeKEY_hek(ret) = save_hek_flags(HeKEY(e), HeKLEN(e), HeHASH(e),
197 HeVAL(ret) = SvREFCNT_inc(sv_dup(HeVAL(e), param));
200 #endif /* USE_ITHREADS */
203 S_hv_notallowed(pTHX_ int flags, const char *key, I32 klen,
206 SV * const sv = sv_newmortal();
207 if (!(flags & HVhek_FREEKEY)) {
208 sv_setpvn(sv, key, klen);
211 /* Need to free saved eventually assign to mortal SV */
212 /* XXX is this line an error ???: SV *sv = sv_newmortal(); */
213 sv_usepvn(sv, (char *) key, klen);
215 if (flags & HVhek_UTF8) {
218 Perl_croak(aTHX_ msg, sv);
221 /* (klen == HEf_SVKEY) is special for MAGICAL hv entries, meaning key slot
224 #define HV_FETCH_ISSTORE 0x01
225 #define HV_FETCH_ISEXISTS 0x02
226 #define HV_FETCH_LVALUE 0x04
227 #define HV_FETCH_JUST_SV 0x08
232 Stores an SV in a hash. The hash key is specified as C<key> and C<klen> is
233 the length of the key. The C<hash> parameter is the precomputed hash
234 value; if it is zero then Perl will compute it. The return value will be
235 NULL if the operation failed or if the value did not need to be actually
236 stored within the hash (as in the case of tied hashes). Otherwise it can
237 be dereferenced to get the original C<SV*>. Note that the caller is
238 responsible for suitably incrementing the reference count of C<val> before
239 the call, and decrementing it if the function returned NULL. Effectively
240 a successful hv_store takes ownership of one reference to C<val>. This is
241 usually what you want; a newly created SV has a reference count of one, so
242 if all your code does is create SVs then store them in a hash, hv_store
243 will own the only reference to the new SV, and your code doesn't need to do
244 anything further to tidy up. hv_store is not implemented as a call to
245 hv_store_ent, and does not create a temporary SV for the key, so if your
246 key data is not already in SV form then use hv_store in preference to
249 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
250 information on how to use this function on tied hashes.
256 Perl_hv_store(pTHX_ HV *hv, const char *key, I32 klen_i32, SV *val, U32 hash)
269 hek = hv_fetch_common (hv, NULL, key, klen, flags,
270 (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), val, hash);
271 return hek ? &HeVAL(hek) : NULL;
274 /* XXX This looks like an ideal candidate to inline */
276 Perl_hv_store_flags(pTHX_ HV *hv, const char *key, I32 klen, SV *val,
277 register U32 hash, int flags)
279 HE * const hek = hv_fetch_common (hv, NULL, key, klen, flags,
280 (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), val, hash);
281 return hek ? &HeVAL(hek) : NULL;
285 =for apidoc hv_store_ent
287 Stores C<val> in a hash. The hash key is specified as C<key>. The C<hash>
288 parameter is the precomputed hash value; if it is zero then Perl will
289 compute it. The return value is the new hash entry so created. It will be
290 NULL if the operation failed or if the value did not need to be actually
291 stored within the hash (as in the case of tied hashes). Otherwise the
292 contents of the return value can be accessed using the C<He?> macros
293 described here. Note that the caller is responsible for suitably
294 incrementing the reference count of C<val> before the call, and
295 decrementing it if the function returned NULL. Effectively a successful
296 hv_store_ent takes ownership of one reference to C<val>. This is
297 usually what you want; a newly created SV has a reference count of one, so
298 if all your code does is create SVs then store them in a hash, hv_store
299 will own the only reference to the new SV, and your code doesn't need to do
300 anything further to tidy up. Note that hv_store_ent only reads the C<key>;
301 unlike C<val> it does not take ownership of it, so maintaining the correct
302 reference count on C<key> is entirely the caller's responsibility. hv_store
303 is not implemented as a call to hv_store_ent, and does not create a temporary
304 SV for the key, so if your key data is not already in SV form then use
305 hv_store in preference to hv_store_ent.
307 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
308 information on how to use this function on tied hashes.
313 /* XXX This looks like an ideal candidate to inline */
315 Perl_hv_store_ent(pTHX_ HV *hv, SV *keysv, SV *val, U32 hash)
317 return hv_fetch_common(hv, keysv, NULL, 0, 0, HV_FETCH_ISSTORE, val, hash);
321 =for apidoc hv_exists
323 Returns a boolean indicating whether the specified hash key exists. The
324 C<klen> is the length of the key.
330 Perl_hv_exists(pTHX_ HV *hv, const char *key, I32 klen_i32)
342 return hv_fetch_common(hv, NULL, key, klen, flags, HV_FETCH_ISEXISTS, 0, 0)
349 Returns the SV which corresponds to the specified key in the hash. The
350 C<klen> is the length of the key. If C<lval> is set then the fetch will be
351 part of a store. Check that the return value is non-null before
352 dereferencing it to an C<SV*>.
354 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
355 information on how to use this function on tied hashes.
361 Perl_hv_fetch(pTHX_ HV *hv, const char *key, I32 klen_i32, I32 lval)
374 hek = hv_fetch_common (hv, NULL, key, klen, flags,
375 lval ? (HV_FETCH_JUST_SV | HV_FETCH_LVALUE) : HV_FETCH_JUST_SV,
377 return hek ? &HeVAL(hek) : NULL;
381 =for apidoc hv_exists_ent
383 Returns a boolean indicating whether the specified hash key exists. C<hash>
384 can be a valid precomputed hash value, or 0 to ask for it to be
390 /* XXX This looks like an ideal candidate to inline */
392 Perl_hv_exists_ent(pTHX_ HV *hv, SV *keysv, U32 hash)
394 return hv_fetch_common(hv, keysv, NULL, 0, 0, HV_FETCH_ISEXISTS, 0, hash)
398 /* returns an HE * structure with the all fields set */
399 /* note that hent_val will be a mortal sv for MAGICAL hashes */
401 =for apidoc hv_fetch_ent
403 Returns the hash entry which corresponds to the specified key in the hash.
404 C<hash> must be a valid precomputed hash number for the given C<key>, or 0
405 if you want the function to compute it. IF C<lval> is set then the fetch
406 will be part of a store. Make sure the return value is non-null before
407 accessing it. The return value when C<tb> is a tied hash is a pointer to a
408 static location, so be sure to make a copy of the structure if you need to
411 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
412 information on how to use this function on tied hashes.
418 Perl_hv_fetch_ent(pTHX_ HV *hv, SV *keysv, I32 lval, register U32 hash)
420 return hv_fetch_common(hv, keysv, NULL, 0, 0,
421 (lval ? HV_FETCH_LVALUE : 0), NULL, hash);
425 S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
426 int flags, int action, SV *val, register U32 hash)
440 if (flags & HVhek_FREEKEY)
442 key = SvPV_const(keysv, klen);
444 is_utf8 = (SvUTF8(keysv) != 0);
446 is_utf8 = ((flags & HVhek_UTF8) ? TRUE : FALSE);
449 xhv = (XPVHV*)SvANY(hv);
451 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, NULL, nkey, klen,
503 HVhek_FREEKEY, /* free nkey */
504 0 /* non-LVAL fetch */,
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 *)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 * const 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;
932 return hv_delete_common(hv, NULL, key, klen, k_flags, flags, 0);
936 =for apidoc hv_delete_ent
938 Deletes a key/value pair in the hash. The value SV is removed from the
939 hash and returned to the caller. The C<flags> value will normally be zero;
940 if set to G_DISCARD then NULL will be returned. C<hash> can be a valid
941 precomputed hash value, or 0 to ask for it to be computed.
946 /* XXX This looks like an ideal candidate to inline */
948 Perl_hv_delete_ent(pTHX_ HV *hv, SV *keysv, I32 flags, U32 hash)
950 return hv_delete_common(hv, keysv, NULL, 0, 0, flags, hash);
954 S_hv_delete_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
955 int k_flags, I32 d_flags, U32 hash)
960 register HE **oentry;
961 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);
985 entry = hv_fetch_common(hv, keysv, key, klen,
986 k_flags & ~HVhek_FREEKEY, HV_FETCH_LVALUE,
988 sv = entry ? HeVAL(entry) : NULL;
994 if (mg_find(sv, PERL_MAGIC_tiedelem)) {
995 /* No longer an element */
996 sv_unmagic(sv, PERL_MAGIC_tiedelem);
999 return NULL; /* element cannot be deleted */
1001 #ifdef ENV_IS_CASELESS
1002 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
1003 /* XXX This code isn't UTF8 clean. */
1004 keysv = sv_2mortal(newSVpvn(key,klen));
1005 if (k_flags & HVhek_FREEKEY) {
1008 key = strupr(SvPVX(keysv));
1017 xhv = (XPVHV*)SvANY(hv);
1022 const char * const keysave = key;
1023 key = (char*)bytes_from_utf8((U8*)key, &klen, &is_utf8);
1026 k_flags |= HVhek_UTF8;
1028 k_flags &= ~HVhek_UTF8;
1029 if (key != keysave) {
1030 if (k_flags & HVhek_FREEKEY) {
1031 /* This shouldn't happen if our caller does what we expect,
1032 but strictly the API allows it. */
1035 k_flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
1037 HvHASKFLAGS_on((SV*)hv);
1041 PERL_HASH_INTERNAL(hash, key, klen);
1043 if (keysv && (SvIsCOW_shared_hash(keysv))) {
1044 hash = SvSHARED_HASH(keysv);
1046 PERL_HASH(hash, key, klen);
1050 masked_flags = (k_flags & HVhek_MASK);
1052 first_entry = oentry = &(HvARRAY(hv))[hash & (I32) HvMAX(hv)];
1054 for (; entry; oentry = &HeNEXT(entry), entry = *oentry) {
1056 if (HeHASH(entry) != hash) /* strings can't be equal */
1058 if (HeKLEN(entry) != (I32)klen)
1060 if (HeKEY(entry) != key && memNE(HeKEY(entry),key,klen)) /* is this it? */
1062 if ((HeKFLAGS(entry) ^ masked_flags) & HVhek_UTF8)
1065 if (hv == PL_strtab) {
1066 if (k_flags & HVhek_FREEKEY)
1068 Perl_croak(aTHX_ S_strtab_error, "delete");
1071 /* if placeholder is here, it's already been deleted.... */
1072 if (HeVAL(entry) == &PL_sv_placeholder) {
1073 if (k_flags & HVhek_FREEKEY)
1077 if (SvREADONLY(hv) && HeVAL(entry) && SvREADONLY(HeVAL(entry))) {
1078 S_hv_notallowed(aTHX_ k_flags, key, klen,
1079 "Attempt to delete readonly key '%"SVf"' from"
1080 " a restricted hash");
1082 if (k_flags & HVhek_FREEKEY)
1085 if (d_flags & G_DISCARD)
1088 sv = sv_2mortal(HeVAL(entry));
1089 HeVAL(entry) = &PL_sv_placeholder;
1093 * If a restricted hash, rather than really deleting the entry, put
1094 * a placeholder there. This marks the key as being "approved", so
1095 * we can still access via not-really-existing key without raising
1098 if (SvREADONLY(hv)) {
1099 SvREFCNT_dec(HeVAL(entry));
1100 HeVAL(entry) = &PL_sv_placeholder;
1101 /* We'll be saving this slot, so the number of allocated keys
1102 * doesn't go down, but the number placeholders goes up */
1103 HvPLACEHOLDERS(hv)++;
1105 *oentry = HeNEXT(entry);
1107 xhv->xhv_fill--; /* HvFILL(hv)-- */
1109 if (SvOOK(hv) && entry == HvAUX(hv)->xhv_eiter /* HvEITER(hv) */)
1112 hv_free_ent(hv, entry);
1113 xhv->xhv_keys--; /* HvKEYS(hv)-- */
1114 if (xhv->xhv_keys == 0)
1115 HvHASKFLAGS_off(hv);
1119 if (SvREADONLY(hv)) {
1120 S_hv_notallowed(aTHX_ k_flags, key, klen,
1121 "Attempt to delete disallowed key '%"SVf"' from"
1122 " a restricted hash");
1125 if (k_flags & HVhek_FREEKEY)
1131 S_hsplit(pTHX_ HV *hv)
1134 register XPVHV* xhv = (XPVHV*)SvANY(hv);
1135 const I32 oldsize = (I32) xhv->xhv_max+1; /* HvMAX(hv)+1 (sick) */
1136 register I32 newsize = oldsize * 2;
1138 char *a = (char*) HvARRAY(hv);
1140 register HE **oentry;
1141 int longest_chain = 0;
1144 /*PerlIO_printf(PerlIO_stderr(), "hsplit called for %p which had %d\n",
1145 hv, (int) oldsize);*/
1147 if (HvPLACEHOLDERS_get(hv) && !SvREADONLY(hv)) {
1148 /* Can make this clear any placeholders first for non-restricted hashes,
1149 even though Storable rebuilds restricted hashes by putting in all the
1150 placeholders (first) before turning on the readonly flag, because
1151 Storable always pre-splits the hash. */
1152 hv_clear_placeholders(hv);
1156 #if defined(STRANGE_MALLOC) || defined(MYMALLOC)
1157 Renew(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1158 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1164 Copy(&a[oldsize * sizeof(HE*)], &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1167 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1168 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1173 Copy(HvARRAY(hv), a, oldsize * sizeof(HE*), char);
1175 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1177 if (oldsize >= 64) {
1178 offer_nice_chunk(HvARRAY(hv),
1179 PERL_HV_ARRAY_ALLOC_BYTES(oldsize)
1180 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0));
1183 Safefree(HvARRAY(hv));
1187 Zero(&a[oldsize * sizeof(HE*)], (newsize-oldsize) * sizeof(HE*), char); /* zero 2nd half*/
1188 xhv->xhv_max = --newsize; /* HvMAX(hv) = --newsize */
1189 HvARRAY(hv) = (HE**) a;
1192 for (i=0; i<oldsize; i++,aep++) {
1193 int left_length = 0;
1194 int right_length = 0;
1198 if (!*aep) /* non-existent */
1201 for (oentry = aep, entry = *aep; entry; entry = *oentry) {
1202 if ((HeHASH(entry) & newsize) != (U32)i) {
1203 *oentry = HeNEXT(entry);
1204 HeNEXT(entry) = *bep;
1206 xhv->xhv_fill++; /* HvFILL(hv)++ */
1212 oentry = &HeNEXT(entry);
1216 if (!*aep) /* everything moved */
1217 xhv->xhv_fill--; /* HvFILL(hv)-- */
1218 /* I think we don't actually need to keep track of the longest length,
1219 merely flag if anything is too long. But for the moment while
1220 developing this code I'll track it. */
1221 if (left_length > longest_chain)
1222 longest_chain = left_length;
1223 if (right_length > longest_chain)
1224 longest_chain = right_length;
1228 /* Pick your policy for "hashing isn't working" here: */
1229 if (longest_chain <= HV_MAX_LENGTH_BEFORE_SPLIT /* split worked? */
1234 if (hv == PL_strtab) {
1235 /* Urg. Someone is doing something nasty to the string table.
1240 /* Awooga. Awooga. Pathological data. */
1241 /*PerlIO_printf(PerlIO_stderr(), "%p %d of %d with %d/%d buckets\n", hv,
1242 longest_chain, HvTOTALKEYS(hv), HvFILL(hv), 1+HvMAX(hv));*/
1245 Newxz(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1246 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1248 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1251 was_shared = HvSHAREKEYS(hv);
1254 HvSHAREKEYS_off(hv);
1259 for (i=0; i<newsize; i++,aep++) {
1260 register HE *entry = *aep;
1262 /* We're going to trash this HE's next pointer when we chain it
1263 into the new hash below, so store where we go next. */
1264 HE * const next = HeNEXT(entry);
1269 PERL_HASH_INTERNAL(hash, HeKEY(entry), HeKLEN(entry));
1274 = save_hek_flags(HeKEY(entry), HeKLEN(entry),
1275 hash, HeKFLAGS(entry));
1276 unshare_hek (HeKEY_hek(entry));
1277 HeKEY_hek(entry) = new_hek;
1279 /* Not shared, so simply write the new hash in. */
1280 HeHASH(entry) = hash;
1282 /*PerlIO_printf(PerlIO_stderr(), "%d ", HeKFLAGS(entry));*/
1283 HEK_REHASH_on(HeKEY_hek(entry));
1284 /*PerlIO_printf(PerlIO_stderr(), "%d\n", HeKFLAGS(entry));*/
1286 /* Copy oentry to the correct new chain. */
1287 bep = ((HE**)a) + (hash & (I32) xhv->xhv_max);
1289 xhv->xhv_fill++; /* HvFILL(hv)++ */
1290 HeNEXT(entry) = *bep;
1296 Safefree (HvARRAY(hv));
1297 HvARRAY(hv) = (HE **)a;
1301 Perl_hv_ksplit(pTHX_ HV *hv, IV newmax)
1304 register XPVHV* xhv = (XPVHV*)SvANY(hv);
1305 const I32 oldsize = (I32) xhv->xhv_max+1; /* HvMAX(hv)+1 (sick) */
1306 register I32 newsize;
1311 register HE **oentry;
1313 newsize = (I32) newmax; /* possible truncation here */
1314 if (newsize != newmax || newmax <= oldsize)
1316 while ((newsize & (1 + ~newsize)) != newsize) {
1317 newsize &= ~(newsize & (1 + ~newsize)); /* get proper power of 2 */
1319 if (newsize < newmax)
1321 if (newsize < newmax)
1322 return; /* overflow detection */
1324 a = (char *) HvARRAY(hv);
1327 #if defined(STRANGE_MALLOC) || defined(MYMALLOC)
1328 Renew(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1329 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1335 Copy(&a[oldsize * sizeof(HE*)], &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1338 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1339 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1344 Copy(HvARRAY(hv), a, oldsize * sizeof(HE*), char);
1346 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1348 if (oldsize >= 64) {
1349 offer_nice_chunk(HvARRAY(hv),
1350 PERL_HV_ARRAY_ALLOC_BYTES(oldsize)
1351 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0));
1354 Safefree(HvARRAY(hv));
1357 Zero(&a[oldsize * sizeof(HE*)], (newsize-oldsize) * sizeof(HE*), char); /* zero 2nd half*/
1360 Newxz(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize), char);
1362 xhv->xhv_max = --newsize; /* HvMAX(hv) = --newsize */
1363 HvARRAY(hv) = (HE **) a;
1364 if (!xhv->xhv_fill /* !HvFILL(hv) */) /* skip rest if no entries */
1368 for (i=0; i<oldsize; i++,aep++) {
1369 if (!*aep) /* non-existent */
1371 for (oentry = aep, entry = *aep; entry; entry = *oentry) {
1372 register I32 j = (HeHASH(entry) & newsize);
1376 *oentry = HeNEXT(entry);
1377 if (!(HeNEXT(entry) = aep[j]))
1378 xhv->xhv_fill++; /* HvFILL(hv)++ */
1383 oentry = &HeNEXT(entry);
1385 if (!*aep) /* everything moved */
1386 xhv->xhv_fill--; /* HvFILL(hv)-- */
1393 Creates a new HV. The reference count is set to 1.
1401 register XPVHV* xhv;
1402 HV * const hv = (HV*)newSV(0);
1404 sv_upgrade((SV *)hv, SVt_PVHV);
1405 xhv = (XPVHV*)SvANY(hv);
1408 #ifndef NODEFAULT_SHAREKEYS
1409 HvSHAREKEYS_on(hv); /* key-sharing on by default */
1412 xhv->xhv_max = 7; /* HvMAX(hv) = 7 (start with 8 buckets) */
1413 xhv->xhv_fill = 0; /* HvFILL(hv) = 0 */
1418 Perl_newHVhv(pTHX_ HV *ohv)
1420 HV * const hv = newHV();
1421 STRLEN hv_max, hv_fill;
1423 if (!ohv || (hv_fill = HvFILL(ohv)) == 0)
1425 hv_max = HvMAX(ohv);
1427 if (!SvMAGICAL((SV *)ohv)) {
1428 /* It's an ordinary hash, so copy it fast. AMS 20010804 */
1430 const bool shared = !!HvSHAREKEYS(ohv);
1431 HE **ents, ** const oents = (HE **)HvARRAY(ohv);
1433 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(hv_max+1), char);
1436 /* In each bucket... */
1437 for (i = 0; i <= hv_max; i++) {
1439 HE *oent = oents[i];
1446 /* Copy the linked list of entries. */
1447 for (; oent; oent = HeNEXT(oent)) {
1448 const U32 hash = HeHASH(oent);
1449 const char * const key = HeKEY(oent);
1450 const STRLEN len = HeKLEN(oent);
1451 const int flags = HeKFLAGS(oent);
1452 HE * const ent = new_HE();
1454 HeVAL(ent) = newSVsv(HeVAL(oent));
1456 = shared ? share_hek_flags(key, len, hash, flags)
1457 : save_hek_flags(key, len, hash, flags);
1468 HvFILL(hv) = hv_fill;
1469 HvTOTALKEYS(hv) = HvTOTALKEYS(ohv);
1473 /* Iterate over ohv, copying keys and values one at a time. */
1475 const I32 riter = HvRITER_get(ohv);
1476 HE * const eiter = HvEITER_get(ohv);
1478 /* Can we use fewer buckets? (hv_max is always 2^n-1) */
1479 while (hv_max && hv_max + 1 >= hv_fill * 2)
1480 hv_max = hv_max / 2;
1484 while ((entry = hv_iternext_flags(ohv, 0))) {
1485 hv_store_flags(hv, HeKEY(entry), HeKLEN(entry),
1486 newSVsv(HeVAL(entry)), HeHASH(entry),
1489 HvRITER_set(ohv, riter);
1490 HvEITER_set(ohv, eiter);
1497 Perl_hv_free_ent(pTHX_ HV *hv, register HE *entry)
1505 if (val && isGV(val) && GvCVu(val) && HvNAME_get(hv))
1506 PL_sub_generation++; /* may be deletion of method from stash */
1508 if (HeKLEN(entry) == HEf_SVKEY) {
1509 SvREFCNT_dec(HeKEY_sv(entry));
1510 Safefree(HeKEY_hek(entry));
1512 else if (HvSHAREKEYS(hv))
1513 unshare_hek(HeKEY_hek(entry));
1515 Safefree(HeKEY_hek(entry));
1520 Perl_hv_delayfree_ent(pTHX_ HV *hv, register HE *entry)
1525 /* SvREFCNT_inc to counter the SvREFCNT_dec in hv_free_ent */
1526 sv_2mortal(SvREFCNT_inc(HeVAL(entry))); /* free between statements */
1527 if (HeKLEN(entry) == HEf_SVKEY) {
1528 sv_2mortal(SvREFCNT_inc(HeKEY_sv(entry)));
1530 hv_free_ent(hv, entry);
1534 =for apidoc hv_clear
1536 Clears a hash, making it empty.
1542 Perl_hv_clear(pTHX_ HV *hv)
1545 register XPVHV* xhv;
1549 DEBUG_A(Perl_hv_assert(aTHX_ hv));
1551 xhv = (XPVHV*)SvANY(hv);
1553 if (SvREADONLY(hv) && HvARRAY(hv) != NULL) {
1554 /* restricted hash: convert all keys to placeholders */
1556 for (i = 0; i <= xhv->xhv_max; i++) {
1557 HE *entry = (HvARRAY(hv))[i];
1558 for (; entry; entry = HeNEXT(entry)) {
1559 /* not already placeholder */
1560 if (HeVAL(entry) != &PL_sv_placeholder) {
1561 if (HeVAL(entry) && SvREADONLY(HeVAL(entry))) {
1562 SV* const keysv = hv_iterkeysv(entry);
1564 "Attempt to delete readonly key '%"SVf"' from a restricted hash",
1567 SvREFCNT_dec(HeVAL(entry));
1568 HeVAL(entry) = &PL_sv_placeholder;
1569 HvPLACEHOLDERS(hv)++;
1577 HvPLACEHOLDERS_set(hv, 0);
1579 (void)memzero(HvARRAY(hv),
1580 (xhv->xhv_max+1 /* HvMAX(hv)+1 */) * sizeof(HE*));
1585 HvHASKFLAGS_off(hv);
1589 HvEITER_set(hv, NULL);
1594 =for apidoc hv_clear_placeholders
1596 Clears any placeholders from a hash. If a restricted hash has any of its keys
1597 marked as readonly and the key is subsequently deleted, the key is not actually
1598 deleted but is marked by assigning it a value of &PL_sv_placeholder. This tags
1599 it so it will be ignored by future operations such as iterating over the hash,
1600 but will still allow the hash to have a value reassigned to the key at some
1601 future point. This function clears any such placeholder keys from the hash.
1602 See Hash::Util::lock_keys() for an example of its use.
1608 Perl_hv_clear_placeholders(pTHX_ HV *hv)
1611 I32 items = (I32)HvPLACEHOLDERS_get(hv);
1619 /* Loop down the linked list heads */
1621 HE **oentry = &(HvARRAY(hv))[i];
1624 while ((entry = *oentry)) {
1625 if (HeVAL(entry) == &PL_sv_placeholder) {
1626 *oentry = HeNEXT(entry);
1627 if (first && !*oentry)
1628 HvFILL(hv)--; /* This linked list is now empty. */
1629 if (entry == HvEITER_get(hv))
1632 hv_free_ent(hv, entry);
1636 HvTOTALKEYS(hv) -= (IV)HvPLACEHOLDERS_get(hv);
1637 if (HvKEYS(hv) == 0)
1638 HvHASKFLAGS_off(hv);
1639 HvPLACEHOLDERS_set(hv, 0);
1643 oentry = &HeNEXT(entry);
1648 /* You can't get here, hence assertion should always fail. */
1649 assert (items == 0);
1654 S_hfreeentries(pTHX_ HV *hv)
1656 /* This is the array that we're going to restore */
1665 /* If the hash is actually a symbol table with a name, look after the
1667 struct xpvhv_aux *iter = HvAUX(hv);
1669 name = iter->xhv_name;
1670 iter->xhv_name = NULL;
1675 orig_array = HvARRAY(hv);
1676 /* orig_array remains unchanged throughout the loop. If after freeing all
1677 the entries it turns out that one of the little blighters has triggered
1678 an action that has caused HvARRAY to be re-allocated, then we set
1679 array to the new HvARRAY, and try again. */
1682 /* This is the one we're going to try to empty. First time round
1683 it's the original array. (Hopefully there will only be 1 time
1685 HE ** const array = HvARRAY(hv);
1688 /* Because we have taken xhv_name out, the only allocated pointer
1689 in the aux structure that might exist is the backreference array.
1694 struct xpvhv_aux *iter = HvAUX(hv);
1695 /* If there are weak references to this HV, we need to avoid
1696 freeing them up here. In particular we need to keep the AV
1697 visible as what we're deleting might well have weak references
1698 back to this HV, so the for loop below may well trigger
1699 the removal of backreferences from this array. */
1701 if (iter->xhv_backreferences) {
1702 /* So donate them to regular backref magic to keep them safe.
1703 The sv_magic will increase the reference count of the AV,
1704 so we need to drop it first. */
1705 SvREFCNT_dec(iter->xhv_backreferences);
1706 if (AvFILLp(iter->xhv_backreferences) == -1) {
1707 /* Turns out that the array is empty. Just free it. */
1708 SvREFCNT_dec(iter->xhv_backreferences);
1711 sv_magic((SV*)hv, (SV*)iter->xhv_backreferences,
1712 PERL_MAGIC_backref, NULL, 0);
1714 iter->xhv_backreferences = NULL;
1717 entry = iter->xhv_eiter; /* HvEITER(hv) */
1718 if (entry && HvLAZYDEL(hv)) { /* was deleted earlier? */
1720 hv_free_ent(hv, entry);
1722 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1723 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1725 /* There are now no allocated pointers in the aux structure. */
1727 SvFLAGS(hv) &= ~SVf_OOK; /* Goodbye, aux structure. */
1728 /* What aux structure? */
1731 /* make everyone else think the array is empty, so that the destructors
1732 * called for freed entries can't recusively mess with us */
1735 ((XPVHV*) SvANY(hv))->xhv_keys = 0;
1739 /* Loop down the linked list heads */
1740 HE *entry = array[i];
1743 register HE * const oentry = entry;
1744 entry = HeNEXT(entry);
1745 hv_free_ent(hv, oentry);
1749 /* As there are no allocated pointers in the aux structure, it's now
1750 safe to free the array we just cleaned up, if it's not the one we're
1751 going to put back. */
1752 if (array != orig_array) {
1757 /* Good. No-one added anything this time round. */
1762 /* Someone attempted to iterate or set the hash name while we had
1763 the array set to 0. We'll catch backferences on the next time
1764 round the while loop. */
1765 assert(HvARRAY(hv));
1767 if (HvAUX(hv)->xhv_name) {
1768 unshare_hek_or_pvn(HvAUX(hv)->xhv_name, 0, 0, 0);
1772 if (--attempts == 0) {
1773 Perl_die(aTHX_ "panic: hfreeentries failed to free hash - something is repeatedly re-creating entries");
1777 HvARRAY(hv) = orig_array;
1779 /* If the hash was actually a symbol table, put the name back. */
1781 /* We have restored the original array. If name is non-NULL, then
1782 the original array had an aux structure at the end. So this is
1784 SvFLAGS(hv) |= SVf_OOK;
1785 HvAUX(hv)->xhv_name = name;
1790 =for apidoc hv_undef
1798 Perl_hv_undef(pTHX_ HV *hv)
1801 register XPVHV* xhv;
1806 DEBUG_A(Perl_hv_assert(aTHX_ hv));
1807 xhv = (XPVHV*)SvANY(hv);
1809 if ((name = HvNAME_get(hv))) {
1811 hv_delete(PL_stashcache, name, HvNAMELEN_get(hv), G_DISCARD);
1812 hv_name_set(hv, NULL, 0, 0);
1814 SvFLAGS(hv) &= ~SVf_OOK;
1815 Safefree(HvARRAY(hv));
1816 xhv->xhv_max = 7; /* HvMAX(hv) = 7 (it's a normal hash) */
1818 HvPLACEHOLDERS_set(hv, 0);
1824 static struct xpvhv_aux*
1825 S_hv_auxinit(pTHX_ HV *hv) {
1826 struct xpvhv_aux *iter;
1830 Newxz(array, PERL_HV_ARRAY_ALLOC_BYTES(HvMAX(hv) + 1)
1831 + sizeof(struct xpvhv_aux), char);
1833 array = (char *) HvARRAY(hv);
1834 Renew(array, PERL_HV_ARRAY_ALLOC_BYTES(HvMAX(hv) + 1)
1835 + sizeof(struct xpvhv_aux), char);
1837 HvARRAY(hv) = (HE**) array;
1838 /* SvOOK_on(hv) attacks the IV flags. */
1839 SvFLAGS(hv) |= SVf_OOK;
1842 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1843 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1845 iter->xhv_backreferences = 0;
1850 =for apidoc hv_iterinit
1852 Prepares a starting point to traverse a hash table. Returns the number of
1853 keys in the hash (i.e. the same as C<HvKEYS(tb)>). The return value is
1854 currently only meaningful for hashes without tie magic.
1856 NOTE: Before version 5.004_65, C<hv_iterinit> used to return the number of
1857 hash buckets that happen to be in use. If you still need that esoteric
1858 value, you can get it through the macro C<HvFILL(tb)>.
1865 Perl_hv_iterinit(pTHX_ HV *hv)
1868 Perl_croak(aTHX_ "Bad hash");
1871 struct xpvhv_aux * const iter = HvAUX(hv);
1872 HE * const entry = iter->xhv_eiter; /* HvEITER(hv) */
1873 if (entry && HvLAZYDEL(hv)) { /* was deleted earlier? */
1875 hv_free_ent(hv, entry);
1877 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1878 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1883 /* used to be xhv->xhv_fill before 5.004_65 */
1884 return HvTOTALKEYS(hv);
1888 Perl_hv_riter_p(pTHX_ HV *hv) {
1889 struct xpvhv_aux *iter;
1892 Perl_croak(aTHX_ "Bad hash");
1894 iter = SvOOK(hv) ? HvAUX(hv) : hv_auxinit(hv);
1895 return &(iter->xhv_riter);
1899 Perl_hv_eiter_p(pTHX_ HV *hv) {
1900 struct xpvhv_aux *iter;
1903 Perl_croak(aTHX_ "Bad hash");
1905 iter = SvOOK(hv) ? HvAUX(hv) : hv_auxinit(hv);
1906 return &(iter->xhv_eiter);
1910 Perl_hv_riter_set(pTHX_ HV *hv, I32 riter) {
1911 struct xpvhv_aux *iter;
1914 Perl_croak(aTHX_ "Bad hash");
1922 iter = hv_auxinit(hv);
1924 iter->xhv_riter = riter;
1928 Perl_hv_eiter_set(pTHX_ HV *hv, HE *eiter) {
1929 struct xpvhv_aux *iter;
1932 Perl_croak(aTHX_ "Bad hash");
1937 /* 0 is the default so don't go malloc()ing a new structure just to
1942 iter = hv_auxinit(hv);
1944 iter->xhv_eiter = eiter;
1948 Perl_hv_name_set(pTHX_ HV *hv, const char *name, I32 len, int flags)
1951 struct xpvhv_aux *iter;
1954 PERL_UNUSED_ARG(flags);
1958 if (iter->xhv_name) {
1959 unshare_hek_or_pvn(iter->xhv_name, 0, 0, 0);
1965 iter = hv_auxinit(hv);
1967 PERL_HASH(hash, name, len);
1968 iter->xhv_name = name ? share_hek(name, len, hash) : 0;
1972 Perl_hv_backreferences_p(pTHX_ HV *hv) {
1973 struct xpvhv_aux * const iter = SvOOK(hv) ? HvAUX(hv) : hv_auxinit(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.he_valu.hent_refcount - 1) {
2284 --he->shared_he_he.he_valu.hent_refcount;
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 was the moral equivalent of:
2304 if ((Svp = hv_fetch(PL_strtab, tmpsv, FALSE, hash))) {
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 (--he->shared_he_he.he_valu.hent_refcount == 0) {
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, NULL, 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 entry->he_valu.hent_refcount = 0;
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 ++entry->he_valu.hent_refcount;
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: