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))) {
451 if (mg_find((SV*)hv, PERL_MAGIC_tied) || SvGMAGICAL((SV*)hv)) {
454 /* XXX should be able to skimp on the HE/HEK here when
455 HV_FETCH_JUST_SV is true. */
458 keysv = newSVpvn(key, klen);
463 keysv = newSVsv(keysv);
465 mg_copy((SV*)hv, sv, (char *)keysv, HEf_SVKEY);
467 /* grab a fake HE/HEK pair from the pool or make a new one */
468 entry = PL_hv_fetch_ent_mh;
470 PL_hv_fetch_ent_mh = HeNEXT(entry);
474 Newx(k, HEK_BASESIZE + sizeof(SV*), char);
475 HeKEY_hek(entry) = (HEK*)k;
477 HeNEXT(entry) = Nullhe;
478 HeSVKEY_set(entry, keysv);
480 sv_upgrade(sv, SVt_PVLV);
482 /* so we can free entry when freeing sv */
483 LvTARG(sv) = (SV*)entry;
485 /* XXX remove at some point? */
486 if (flags & HVhek_FREEKEY)
491 #ifdef ENV_IS_CASELESS
492 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
494 for (i = 0; i < klen; ++i)
495 if (isLOWER(key[i])) {
496 /* Would be nice if we had a routine to do the
497 copy and upercase in a single pass through. */
498 const char * const nkey = strupr(savepvn(key,klen));
499 /* Note that this fetch is for nkey (the uppercased
500 key) whereas the store is for key (the original) */
501 entry = hv_fetch_common(hv, Nullsv, nkey, klen,
502 HVhek_FREEKEY, /* free nkey */
503 0 /* non-LVAL fetch */,
504 Nullsv /* no value */,
505 0 /* compute hash */);
506 if (!entry && (action & HV_FETCH_LVALUE)) {
507 /* This call will free key if necessary.
508 Do it this way to encourage compiler to tail
510 entry = hv_fetch_common(hv, keysv, key, klen,
511 flags, HV_FETCH_ISSTORE,
514 if (flags & HVhek_FREEKEY)
522 else if (SvRMAGICAL(hv) && (action & HV_FETCH_ISEXISTS)) {
523 if (mg_find((SV*)hv, PERL_MAGIC_tied) || SvGMAGICAL((SV*)hv)) {
524 /* I don't understand why hv_exists_ent has svret and sv,
525 whereas hv_exists only had one. */
526 SV * const svret = sv_newmortal();
529 if (keysv || is_utf8) {
531 keysv = newSVpvn(key, klen);
534 keysv = newSVsv(keysv);
536 mg_copy((SV*)hv, sv, (char *)sv_2mortal(keysv), HEf_SVKEY);
538 mg_copy((SV*)hv, sv, key, klen);
540 if (flags & HVhek_FREEKEY)
542 magic_existspack(svret, mg_find(sv, PERL_MAGIC_tiedelem));
543 /* This cast somewhat evil, but I'm merely using NULL/
544 not NULL to return the boolean exists.
545 And I know hv is not NULL. */
546 return SvTRUE(svret) ? (HE *)hv : NULL;
548 #ifdef ENV_IS_CASELESS
549 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
550 /* XXX This code isn't UTF8 clean. */
551 char * const keysave = (char * const)key;
552 /* Will need to free this, so set FREEKEY flag. */
553 key = savepvn(key,klen);
554 key = (const char*)strupr((char*)key);
559 if (flags & HVhek_FREEKEY) {
562 flags |= HVhek_FREEKEY;
566 else if (action & HV_FETCH_ISSTORE) {
569 hv_magic_check (hv, &needs_copy, &needs_store);
571 const bool save_taint = PL_tainted;
572 if (keysv || is_utf8) {
574 keysv = newSVpvn(key, klen);
578 PL_tainted = SvTAINTED(keysv);
579 keysv = sv_2mortal(newSVsv(keysv));
580 mg_copy((SV*)hv, val, (char*)keysv, HEf_SVKEY);
582 mg_copy((SV*)hv, val, key, klen);
585 TAINT_IF(save_taint);
586 if (!HvARRAY(hv) && !needs_store) {
587 if (flags & HVhek_FREEKEY)
591 #ifdef ENV_IS_CASELESS
592 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
593 /* XXX This code isn't UTF8 clean. */
594 const char *keysave = key;
595 /* Will need to free this, so set FREEKEY flag. */
596 key = savepvn(key,klen);
597 key = (const char*)strupr((char*)key);
602 if (flags & HVhek_FREEKEY) {
605 flags |= HVhek_FREEKEY;
613 if ((action & (HV_FETCH_LVALUE | HV_FETCH_ISSTORE))
614 #ifdef DYNAMIC_ENV_FETCH /* if it's an %ENV lookup, we may get it on the fly */
615 || (SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env))
620 PERL_HV_ARRAY_ALLOC_BYTES(xhv->xhv_max+1 /* HvMAX(hv)+1 */),
622 HvARRAY(hv) = (HE**)array;
624 #ifdef DYNAMIC_ENV_FETCH
625 else if (action & HV_FETCH_ISEXISTS) {
626 /* for an %ENV exists, if we do an insert it's by a recursive
627 store call, so avoid creating HvARRAY(hv) right now. */
631 /* XXX remove at some point? */
632 if (flags & HVhek_FREEKEY)
640 char * const keysave = (char * const)key;
641 key = (char*)bytes_from_utf8((U8*)key, &klen, &is_utf8);
645 flags &= ~HVhek_UTF8;
646 if (key != keysave) {
647 if (flags & HVhek_FREEKEY)
649 flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
654 PERL_HASH_INTERNAL(hash, key, klen);
655 /* We don't have a pointer to the hv, so we have to replicate the
656 flag into every HEK, so that hv_iterkeysv can see it. */
657 /* And yes, you do need this even though you are not "storing" because
658 you can flip the flags below if doing an lval lookup. (And that
659 was put in to give the semantics Andreas was expecting.) */
660 flags |= HVhek_REHASH;
662 if (keysv && (SvIsCOW_shared_hash(keysv))) {
663 hash = SvSHARED_HASH(keysv);
665 PERL_HASH(hash, key, klen);
669 masked_flags = (flags & HVhek_MASK);
671 #ifdef DYNAMIC_ENV_FETCH
672 if (!HvARRAY(hv)) entry = Null(HE*);
676 entry = (HvARRAY(hv))[hash & (I32) HvMAX(hv)];
678 for (; entry; entry = HeNEXT(entry)) {
679 if (HeHASH(entry) != hash) /* strings can't be equal */
681 if (HeKLEN(entry) != (I32)klen)
683 if (HeKEY(entry) != key && memNE(HeKEY(entry),key,klen)) /* is this it? */
685 if ((HeKFLAGS(entry) ^ masked_flags) & HVhek_UTF8)
688 if (action & (HV_FETCH_LVALUE|HV_FETCH_ISSTORE)) {
689 if (HeKFLAGS(entry) != masked_flags) {
690 /* We match if HVhek_UTF8 bit in our flags and hash key's
691 match. But if entry was set previously with HVhek_WASUTF8
692 and key now doesn't (or vice versa) then we should change
693 the key's flag, as this is assignment. */
694 if (HvSHAREKEYS(hv)) {
695 /* Need to swap the key we have for a key with the flags we
696 need. As keys are shared we can't just write to the
697 flag, so we share the new one, unshare the old one. */
698 HEK * const new_hek = share_hek_flags(key, klen, hash,
700 unshare_hek (HeKEY_hek(entry));
701 HeKEY_hek(entry) = new_hek;
703 else if (hv == PL_strtab) {
704 /* PL_strtab is usually the only hash without HvSHAREKEYS,
705 so putting this test here is cheap */
706 if (flags & HVhek_FREEKEY)
708 Perl_croak(aTHX_ S_strtab_error,
709 action & HV_FETCH_LVALUE ? "fetch" : "store");
712 HeKFLAGS(entry) = masked_flags;
713 if (masked_flags & HVhek_ENABLEHVKFLAGS)
716 if (HeVAL(entry) == &PL_sv_placeholder) {
717 /* yes, can store into placeholder slot */
718 if (action & HV_FETCH_LVALUE) {
720 /* This preserves behaviour with the old hv_fetch
721 implementation which at this point would bail out
722 with a break; (at "if we find a placeholder, we
723 pretend we haven't found anything")
725 That break mean that if a placeholder were found, it
726 caused a call into hv_store, which in turn would
727 check magic, and if there is no magic end up pretty
728 much back at this point (in hv_store's code). */
731 /* LVAL fetch which actaully needs a store. */
733 HvPLACEHOLDERS(hv)--;
736 if (val != &PL_sv_placeholder)
737 HvPLACEHOLDERS(hv)--;
740 } else if (action & HV_FETCH_ISSTORE) {
741 SvREFCNT_dec(HeVAL(entry));
744 } else if (HeVAL(entry) == &PL_sv_placeholder) {
745 /* if we find a placeholder, we pretend we haven't found
749 if (flags & HVhek_FREEKEY)
753 #ifdef DYNAMIC_ENV_FETCH /* %ENV lookup? If so, try to fetch the value now */
754 if (!(action & HV_FETCH_ISSTORE)
755 && SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env)) {
757 const char * const env = PerlEnv_ENVgetenv_len(key,&len);
759 sv = newSVpvn(env,len);
761 return hv_fetch_common(hv,keysv,key,klen,flags,HV_FETCH_ISSTORE,sv,
767 if (!entry && SvREADONLY(hv) && !(action & HV_FETCH_ISEXISTS)) {
768 hv_notallowed(flags, key, klen,
769 "Attempt to access disallowed key '%"SVf"' in"
770 " a restricted hash");
772 if (!(action & (HV_FETCH_LVALUE|HV_FETCH_ISSTORE))) {
773 /* Not doing some form of store, so return failure. */
774 if (flags & HVhek_FREEKEY)
778 if (action & HV_FETCH_LVALUE) {
781 /* At this point the old hv_fetch code would call to hv_store,
782 which in turn might do some tied magic. So we need to make that
783 magic check happen. */
784 /* gonna assign to this, so it better be there */
785 return hv_fetch_common(hv, keysv, key, klen, flags,
786 HV_FETCH_ISSTORE, val, hash);
787 /* XXX Surely that could leak if the fetch-was-store fails?
788 Just like the hv_fetch. */
792 /* Welcome to hv_store... */
795 /* Not sure if we can get here. I think the only case of oentry being
796 NULL is for %ENV with dynamic env fetch. But that should disappear
797 with magic in the previous code. */
800 PERL_HV_ARRAY_ALLOC_BYTES(xhv->xhv_max+1 /* HvMAX(hv)+1 */),
802 HvARRAY(hv) = (HE**)array;
805 oentry = &(HvARRAY(hv))[hash & (I32) xhv->xhv_max];
808 /* share_hek_flags will do the free for us. This might be considered
811 HeKEY_hek(entry) = share_hek_flags(key, klen, hash, flags);
812 else if (hv == PL_strtab) {
813 /* PL_strtab is usually the only hash without HvSHAREKEYS, so putting
814 this test here is cheap */
815 if (flags & HVhek_FREEKEY)
817 Perl_croak(aTHX_ S_strtab_error,
818 action & HV_FETCH_LVALUE ? "fetch" : "store");
820 else /* gotta do the real thing */
821 HeKEY_hek(entry) = save_hek_flags(key, klen, hash, flags);
823 HeNEXT(entry) = *oentry;
826 if (val == &PL_sv_placeholder)
827 HvPLACEHOLDERS(hv)++;
828 if (masked_flags & HVhek_ENABLEHVKFLAGS)
832 const HE *counter = HeNEXT(entry);
834 xhv->xhv_keys++; /* HvKEYS(hv)++ */
835 if (!counter) { /* initial entry? */
836 xhv->xhv_fill++; /* HvFILL(hv)++ */
837 } else if (xhv->xhv_keys > (IV)xhv->xhv_max) {
839 } else if(!HvREHASH(hv)) {
842 while ((counter = HeNEXT(counter)))
845 if (n_links > HV_MAX_LENGTH_BEFORE_SPLIT) {
846 /* Use only the old HvKEYS(hv) > HvMAX(hv) condition to limit
847 bucket splits on a rehashed hash, as we're not going to
848 split it again, and if someone is lucky (evil) enough to
849 get all the keys in one list they could exhaust our memory
850 as we repeatedly double the number of buckets on every
851 entry. Linear search feels a less worse thing to do. */
861 S_hv_magic_check(pTHX_ HV *hv, bool *needs_copy, bool *needs_store)
863 const MAGIC *mg = SvMAGIC(hv);
867 if (isUPPER(mg->mg_type)) {
869 if (mg->mg_type == PERL_MAGIC_tied) {
870 *needs_store = FALSE;
871 return; /* We've set all there is to set. */
874 mg = mg->mg_moremagic;
879 =for apidoc hv_scalar
881 Evaluates the hash in scalar context and returns the result. Handles magic when the hash is tied.
887 Perl_hv_scalar(pTHX_ HV *hv)
891 if (SvRMAGICAL(hv)) {
892 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_tied);
894 return magic_scalarpack(hv, mg);
899 Perl_sv_setpvf(aTHX_ sv, "%ld/%ld",
900 (long)HvFILL(hv), (long)HvMAX(hv) + 1);
908 =for apidoc hv_delete
910 Deletes a key/value pair in the hash. The value SV is removed from the
911 hash and returned to the caller. The C<klen> is the length of the key.
912 The C<flags> value will normally be zero; if set to G_DISCARD then NULL
919 Perl_hv_delete(pTHX_ HV *hv, const char *key, I32 klen_i32, I32 flags)
926 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;
968 if (k_flags & HVhek_FREEKEY)
970 key = SvPV_const(keysv, klen);
972 is_utf8 = (SvUTF8(keysv) != 0);
974 is_utf8 = ((k_flags & HVhek_UTF8) ? TRUE : FALSE);
977 if (SvRMAGICAL(hv)) {
980 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) {
1055 if (HeHASH(entry) != hash) /* strings can't be equal */
1057 if (HeKLEN(entry) != (I32)klen)
1059 if (HeKEY(entry) != key && memNE(HeKEY(entry),key,klen)) /* is this it? */
1061 if ((HeKFLAGS(entry) ^ masked_flags) & HVhek_UTF8)
1064 if (hv == PL_strtab) {
1065 if (k_flags & HVhek_FREEKEY)
1067 Perl_croak(aTHX_ S_strtab_error, "delete");
1070 /* if placeholder is here, it's already been deleted.... */
1071 if (HeVAL(entry) == &PL_sv_placeholder) {
1072 if (k_flags & HVhek_FREEKEY)
1076 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) {
1371 register I32 j = (HeHASH(entry) & newsize);
1375 *oentry = HeNEXT(entry);
1376 if (!(HeNEXT(entry) = aep[j]))
1377 xhv->xhv_fill++; /* HvFILL(hv)++ */
1382 oentry = &HeNEXT(entry);
1384 if (!*aep) /* everything moved */
1385 xhv->xhv_fill--; /* HvFILL(hv)-- */
1392 Creates a new HV. The reference count is set to 1.
1400 register XPVHV* xhv;
1401 HV * const hv = (HV*)NEWSV(502,0);
1403 sv_upgrade((SV *)hv, SVt_PVHV);
1404 xhv = (XPVHV*)SvANY(hv);
1407 #ifndef NODEFAULT_SHAREKEYS
1408 HvSHAREKEYS_on(hv); /* key-sharing on by default */
1411 xhv->xhv_max = 7; /* HvMAX(hv) = 7 (start with 8 buckets) */
1412 xhv->xhv_fill = 0; /* HvFILL(hv) = 0 */
1417 Perl_newHVhv(pTHX_ HV *ohv)
1419 HV * const hv = newHV();
1420 STRLEN hv_max, hv_fill;
1422 if (!ohv || (hv_fill = HvFILL(ohv)) == 0)
1424 hv_max = HvMAX(ohv);
1426 if (!SvMAGICAL((SV *)ohv)) {
1427 /* It's an ordinary hash, so copy it fast. AMS 20010804 */
1429 const bool shared = !!HvSHAREKEYS(ohv);
1430 HE **ents, ** const oents = (HE **)HvARRAY(ohv);
1432 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(hv_max+1), char);
1435 /* In each bucket... */
1436 for (i = 0; i <= hv_max; i++) {
1438 HE *oent = oents[i];
1445 /* Copy the linked list of entries. */
1446 for (; oent; oent = HeNEXT(oent)) {
1447 const U32 hash = HeHASH(oent);
1448 const char * const key = HeKEY(oent);
1449 const STRLEN len = HeKLEN(oent);
1450 const int flags = HeKFLAGS(oent);
1451 HE * const ent = new_HE();
1453 HeVAL(ent) = newSVsv(HeVAL(oent));
1455 = shared ? share_hek_flags(key, len, hash, flags)
1456 : save_hek_flags(key, len, hash, flags);
1467 HvFILL(hv) = hv_fill;
1468 HvTOTALKEYS(hv) = HvTOTALKEYS(ohv);
1472 /* Iterate over ohv, copying keys and values one at a time. */
1474 const I32 riter = HvRITER_get(ohv);
1475 HE * const eiter = HvEITER_get(ohv);
1477 /* Can we use fewer buckets? (hv_max is always 2^n-1) */
1478 while (hv_max && hv_max + 1 >= hv_fill * 2)
1479 hv_max = hv_max / 2;
1483 while ((entry = hv_iternext_flags(ohv, 0))) {
1484 hv_store_flags(hv, HeKEY(entry), HeKLEN(entry),
1485 newSVsv(HeVAL(entry)), HeHASH(entry),
1488 HvRITER_set(ohv, riter);
1489 HvEITER_set(ohv, eiter);
1496 Perl_hv_free_ent(pTHX_ HV *hv, register HE *entry)
1504 if (val && isGV(val) && GvCVu(val) && HvNAME_get(hv))
1505 PL_sub_generation++; /* may be deletion of method from stash */
1507 if (HeKLEN(entry) == HEf_SVKEY) {
1508 SvREFCNT_dec(HeKEY_sv(entry));
1509 Safefree(HeKEY_hek(entry));
1511 else if (HvSHAREKEYS(hv))
1512 unshare_hek(HeKEY_hek(entry));
1514 Safefree(HeKEY_hek(entry));
1519 Perl_hv_delayfree_ent(pTHX_ HV *hv, register HE *entry)
1524 /* SvREFCNT_inc to counter the SvREFCNT_dec in hv_free_ent */
1525 sv_2mortal(SvREFCNT_inc(HeVAL(entry))); /* free between statements */
1526 if (HeKLEN(entry) == HEf_SVKEY) {
1527 sv_2mortal(SvREFCNT_inc(HeKEY_sv(entry)));
1529 hv_free_ent(hv, entry);
1533 =for apidoc hv_clear
1535 Clears a hash, making it empty.
1541 Perl_hv_clear(pTHX_ HV *hv)
1544 register XPVHV* xhv;
1548 DEBUG_A(Perl_hv_assert(aTHX_ hv));
1550 xhv = (XPVHV*)SvANY(hv);
1552 if (SvREADONLY(hv) && HvARRAY(hv) != NULL) {
1553 /* restricted hash: convert all keys to placeholders */
1555 for (i = 0; i <= xhv->xhv_max; i++) {
1556 HE *entry = (HvARRAY(hv))[i];
1557 for (; entry; entry = HeNEXT(entry)) {
1558 /* not already placeholder */
1559 if (HeVAL(entry) != &PL_sv_placeholder) {
1560 if (HeVAL(entry) && SvREADONLY(HeVAL(entry))) {
1561 SV* const keysv = hv_iterkeysv(entry);
1563 "Attempt to delete readonly key '%"SVf"' from a restricted hash",
1566 SvREFCNT_dec(HeVAL(entry));
1567 HeVAL(entry) = &PL_sv_placeholder;
1568 HvPLACEHOLDERS(hv)++;
1576 HvPLACEHOLDERS_set(hv, 0);
1578 (void)memzero(HvARRAY(hv),
1579 (xhv->xhv_max+1 /* HvMAX(hv)+1 */) * sizeof(HE*));
1584 HvHASKFLAGS_off(hv);
1588 HvEITER_set(hv, NULL);
1593 =for apidoc hv_clear_placeholders
1595 Clears any placeholders from a hash. If a restricted hash has any of its keys
1596 marked as readonly and the key is subsequently deleted, the key is not actually
1597 deleted but is marked by assigning it a value of &PL_sv_placeholder. This tags
1598 it so it will be ignored by future operations such as iterating over the hash,
1599 but will still allow the hash to have a value reassigned to the key at some
1600 future point. This function clears any such placeholder keys from the hash.
1601 See Hash::Util::lock_keys() for an example of its use.
1607 Perl_hv_clear_placeholders(pTHX_ HV *hv)
1610 I32 items = (I32)HvPLACEHOLDERS_get(hv);
1618 /* Loop down the linked list heads */
1620 HE **oentry = &(HvARRAY(hv))[i];
1623 while ((entry = *oentry)) {
1624 if (HeVAL(entry) == &PL_sv_placeholder) {
1625 *oentry = HeNEXT(entry);
1626 if (first && !*oentry)
1627 HvFILL(hv)--; /* This linked list is now empty. */
1628 if (entry == HvEITER_get(hv))
1631 hv_free_ent(hv, entry);
1635 HvTOTALKEYS(hv) -= (IV)HvPLACEHOLDERS_get(hv);
1636 if (HvKEYS(hv) == 0)
1637 HvHASKFLAGS_off(hv);
1638 HvPLACEHOLDERS_set(hv, 0);
1642 oentry = &HeNEXT(entry);
1647 /* You can't get here, hence assertion should always fail. */
1648 assert (items == 0);
1653 S_hfreeentries(pTHX_ HV *hv)
1655 /* This is the array that we're going to restore */
1664 /* If the hash is actually a symbol table with a name, look after the
1666 struct xpvhv_aux *iter = HvAUX(hv);
1668 name = iter->xhv_name;
1669 iter->xhv_name = NULL;
1674 orig_array = HvARRAY(hv);
1675 /* orig_array remains unchanged throughout the loop. If after freeing all
1676 the entries it turns out that one of the little blighters has triggered
1677 an action that has caused HvARRAY to be re-allocated, then we set
1678 array to the new HvARRAY, and try again. */
1681 /* This is the one we're going to try to empty. First time round
1682 it's the original array. (Hopefully there will only be 1 time
1684 HE ** const array = HvARRAY(hv);
1687 /* Because we have taken xhv_name out, the only allocated pointer
1688 in the aux structure that might exist is the backreference array.
1693 struct xpvhv_aux *iter = HvAUX(hv);
1694 /* If there are weak references to this HV, we need to avoid
1695 freeing them up here. In particular we need to keep the AV
1696 visible as what we're deleting might well have weak references
1697 back to this HV, so the for loop below may well trigger
1698 the removal of backreferences from this array. */
1700 if (iter->xhv_backreferences) {
1701 /* So donate them to regular backref magic to keep them safe.
1702 The sv_magic will increase the reference count of the AV,
1703 so we need to drop it first. */
1704 SvREFCNT_dec(iter->xhv_backreferences);
1705 if (AvFILLp(iter->xhv_backreferences) == -1) {
1706 /* Turns out that the array is empty. Just free it. */
1707 SvREFCNT_dec(iter->xhv_backreferences);
1710 sv_magic((SV*)hv, (SV*)iter->xhv_backreferences,
1711 PERL_MAGIC_backref, NULL, 0);
1713 iter->xhv_backreferences = NULL;
1716 entry = iter->xhv_eiter; /* HvEITER(hv) */
1717 if (entry && HvLAZYDEL(hv)) { /* was deleted earlier? */
1719 hv_free_ent(hv, entry);
1721 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1722 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1724 /* There are now no allocated pointers in the aux structure. */
1726 SvFLAGS(hv) &= ~SVf_OOK; /* Goodbye, aux structure. */
1727 /* What aux structure? */
1730 /* make everyone else think the array is empty, so that the destructors
1731 * called for freed entries can't recusively mess with us */
1734 ((XPVHV*) SvANY(hv))->xhv_keys = 0;
1738 /* Loop down the linked list heads */
1739 HE *entry = array[i];
1742 register HE * const oentry = entry;
1743 entry = HeNEXT(entry);
1744 hv_free_ent(hv, oentry);
1748 /* As there are no allocated pointers in the aux structure, it's now
1749 safe to free the array we just cleaned up, if it's not the one we're
1750 going to put back. */
1751 if (array != orig_array) {
1756 /* Good. No-one added anything this time round. */
1761 /* Someone attempted to iterate or set the hash name while we had
1762 the array set to 0. We'll catch backferences on the next time
1763 round the while loop. */
1764 assert(HvARRAY(hv));
1766 if (HvAUX(hv)->xhv_name) {
1767 unshare_hek_or_pvn(HvAUX(hv)->xhv_name, 0, 0, 0);
1771 if (--attempts == 0) {
1772 Perl_die(aTHX_ "panic: hfreeentries failed to free hash - something is repeatedly re-creating entries");
1776 HvARRAY(hv) = orig_array;
1778 /* If the hash was actually a symbol table, put the name back. */
1780 /* We have restored the original array. If name is non-NULL, then
1781 the original array had an aux structure at the end. So this is
1783 SvFLAGS(hv) |= SVf_OOK;
1784 HvAUX(hv)->xhv_name = name;
1789 =for apidoc hv_undef
1797 Perl_hv_undef(pTHX_ HV *hv)
1800 register XPVHV* xhv;
1805 DEBUG_A(Perl_hv_assert(aTHX_ hv));
1806 xhv = (XPVHV*)SvANY(hv);
1808 if ((name = HvNAME_get(hv))) {
1810 hv_delete(PL_stashcache, name, HvNAMELEN_get(hv), G_DISCARD);
1811 hv_name_set(hv, Nullch, 0, 0);
1813 SvFLAGS(hv) &= ~SVf_OOK;
1814 Safefree(HvARRAY(hv));
1815 xhv->xhv_max = 7; /* HvMAX(hv) = 7 (it's a normal hash) */
1817 HvPLACEHOLDERS_set(hv, 0);
1823 static struct xpvhv_aux*
1824 S_hv_auxinit(pTHX_ HV *hv) {
1825 struct xpvhv_aux *iter;
1829 Newxz(array, PERL_HV_ARRAY_ALLOC_BYTES(HvMAX(hv) + 1)
1830 + sizeof(struct xpvhv_aux), char);
1832 array = (char *) HvARRAY(hv);
1833 Renew(array, PERL_HV_ARRAY_ALLOC_BYTES(HvMAX(hv) + 1)
1834 + sizeof(struct xpvhv_aux), char);
1836 HvARRAY(hv) = (HE**) array;
1837 /* SvOOK_on(hv) attacks the IV flags. */
1838 SvFLAGS(hv) |= SVf_OOK;
1841 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1842 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1844 iter->xhv_backreferences = 0;
1849 =for apidoc hv_iterinit
1851 Prepares a starting point to traverse a hash table. Returns the number of
1852 keys in the hash (i.e. the same as C<HvKEYS(tb)>). The return value is
1853 currently only meaningful for hashes without tie magic.
1855 NOTE: Before version 5.004_65, C<hv_iterinit> used to return the number of
1856 hash buckets that happen to be in use. If you still need that esoteric
1857 value, you can get it through the macro C<HvFILL(tb)>.
1864 Perl_hv_iterinit(pTHX_ HV *hv)
1867 Perl_croak(aTHX_ "Bad hash");
1870 struct xpvhv_aux * const iter = HvAUX(hv);
1871 HE * const entry = iter->xhv_eiter; /* HvEITER(hv) */
1872 if (entry && HvLAZYDEL(hv)) { /* was deleted earlier? */
1874 hv_free_ent(hv, entry);
1876 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1877 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1882 /* used to be xhv->xhv_fill before 5.004_65 */
1883 return HvTOTALKEYS(hv);
1887 Perl_hv_riter_p(pTHX_ HV *hv) {
1888 struct xpvhv_aux *iter;
1891 Perl_croak(aTHX_ "Bad hash");
1893 iter = SvOOK(hv) ? HvAUX(hv) : hv_auxinit(hv);
1894 return &(iter->xhv_riter);
1898 Perl_hv_eiter_p(pTHX_ HV *hv) {
1899 struct xpvhv_aux *iter;
1902 Perl_croak(aTHX_ "Bad hash");
1904 iter = SvOOK(hv) ? HvAUX(hv) : hv_auxinit(hv);
1905 return &(iter->xhv_eiter);
1909 Perl_hv_riter_set(pTHX_ HV *hv, I32 riter) {
1910 struct xpvhv_aux *iter;
1913 Perl_croak(aTHX_ "Bad hash");
1921 iter = hv_auxinit(hv);
1923 iter->xhv_riter = riter;
1927 Perl_hv_eiter_set(pTHX_ HV *hv, HE *eiter) {
1928 struct xpvhv_aux *iter;
1931 Perl_croak(aTHX_ "Bad hash");
1936 /* 0 is the default so don't go malloc()ing a new structure just to
1941 iter = hv_auxinit(hv);
1943 iter->xhv_eiter = eiter;
1947 Perl_hv_name_set(pTHX_ HV *hv, const char *name, I32 len, int flags)
1950 struct xpvhv_aux *iter;
1953 PERL_UNUSED_ARG(flags);
1957 if (iter->xhv_name) {
1958 unshare_hek_or_pvn(iter->xhv_name, 0, 0, 0);
1964 iter = hv_auxinit(hv);
1966 PERL_HASH(hash, name, len);
1967 iter->xhv_name = name ? share_hek(name, len, hash) : 0;
1971 Perl_hv_backreferences_p(pTHX_ HV *hv) {
1972 struct xpvhv_aux * const iter = SvOOK(hv) ? HvAUX(hv) : hv_auxinit(hv);
1973 return &(iter->xhv_backreferences);
1977 Perl_hv_kill_backrefs(pTHX_ HV *hv) {
1983 av = HvAUX(hv)->xhv_backreferences;
1986 HvAUX(hv)->xhv_backreferences = 0;
1987 Perl_sv_kill_backrefs(aTHX_ (SV*) hv, av);
1992 hv_iternext is implemented as a macro in hv.h
1994 =for apidoc hv_iternext
1996 Returns entries from a hash iterator. See C<hv_iterinit>.
1998 You may call C<hv_delete> or C<hv_delete_ent> on the hash entry that the
1999 iterator currently points to, without losing your place or invalidating your
2000 iterator. Note that in this case the current entry is deleted from the hash
2001 with your iterator holding the last reference to it. Your iterator is flagged
2002 to free the entry on the next call to C<hv_iternext>, so you must not discard
2003 your iterator immediately else the entry will leak - call C<hv_iternext> to
2004 trigger the resource deallocation.
2006 =for apidoc hv_iternext_flags
2008 Returns entries from a hash iterator. See C<hv_iterinit> and C<hv_iternext>.
2009 The C<flags> value will normally be zero; if HV_ITERNEXT_WANTPLACEHOLDERS is
2010 set the placeholders keys (for restricted hashes) will be returned in addition
2011 to normal keys. By default placeholders are automatically skipped over.
2012 Currently a placeholder is implemented with a value that is
2013 C<&Perl_sv_placeholder>. Note that the implementation of placeholders and
2014 restricted hashes may change, and the implementation currently is
2015 insufficiently abstracted for any change to be tidy.
2021 Perl_hv_iternext_flags(pTHX_ HV *hv, I32 flags)
2024 register XPVHV* xhv;
2028 struct xpvhv_aux *iter;
2031 Perl_croak(aTHX_ "Bad hash");
2032 xhv = (XPVHV*)SvANY(hv);
2035 /* Too many things (well, pp_each at least) merrily assume that you can
2036 call iv_iternext without calling hv_iterinit, so we'll have to deal
2042 oldentry = entry = iter->xhv_eiter; /* HvEITER(hv) */
2044 if ((mg = SvTIED_mg((SV*)hv, PERL_MAGIC_tied))) {
2045 SV * const key = sv_newmortal();
2047 sv_setsv(key, HeSVKEY_force(entry));
2048 SvREFCNT_dec(HeSVKEY(entry)); /* get rid of previous key */
2054 /* one HE per MAGICAL hash */
2055 iter->xhv_eiter = entry = new_HE(); /* HvEITER(hv) = new_HE() */
2057 Newxz(k, HEK_BASESIZE + sizeof(SV*), char);
2059 HeKEY_hek(entry) = hek;
2060 HeKLEN(entry) = HEf_SVKEY;
2062 magic_nextpack((SV*) hv,mg,key);
2064 /* force key to stay around until next time */
2065 HeSVKEY_set(entry, SvREFCNT_inc(key));
2066 return entry; /* beware, hent_val is not set */
2069 SvREFCNT_dec(HeVAL(entry));
2070 Safefree(HeKEY_hek(entry));
2072 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
2075 #ifdef DYNAMIC_ENV_FETCH /* set up %ENV for iteration */
2076 if (!entry && SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env)) {
2079 /* The prime_env_iter() on VMS just loaded up new hash values
2080 * so the iteration count needs to be reset back to the beginning
2084 oldentry = entry = iter->xhv_eiter; /* HvEITER(hv) */
2089 /* hv_iterint now ensures this. */
2090 assert (HvARRAY(hv));
2092 /* At start of hash, entry is NULL. */
2095 entry = HeNEXT(entry);
2096 if (!(flags & HV_ITERNEXT_WANTPLACEHOLDERS)) {
2098 * Skip past any placeholders -- don't want to include them in
2101 while (entry && HeVAL(entry) == &PL_sv_placeholder) {
2102 entry = HeNEXT(entry);
2107 /* OK. Come to the end of the current list. Grab the next one. */
2109 iter->xhv_riter++; /* HvRITER(hv)++ */
2110 if (iter->xhv_riter > (I32)xhv->xhv_max /* HvRITER(hv) > HvMAX(hv) */) {
2111 /* There is no next one. End of the hash. */
2112 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
2115 entry = (HvARRAY(hv))[iter->xhv_riter];
2117 if (!(flags & HV_ITERNEXT_WANTPLACEHOLDERS)) {
2118 /* If we have an entry, but it's a placeholder, don't count it.
2120 while (entry && HeVAL(entry) == &PL_sv_placeholder)
2121 entry = HeNEXT(entry);
2123 /* Will loop again if this linked list starts NULL
2124 (for HV_ITERNEXT_WANTPLACEHOLDERS)
2125 or if we run through it and find only placeholders. */
2128 if (oldentry && HvLAZYDEL(hv)) { /* was deleted earlier? */
2130 hv_free_ent(hv, oldentry);
2133 /*if (HvREHASH(hv) && entry && !HeKREHASH(entry))
2134 PerlIO_printf(PerlIO_stderr(), "Awooga %p %p\n", hv, entry);*/
2136 iter->xhv_eiter = entry; /* HvEITER(hv) = entry */
2141 =for apidoc hv_iterkey
2143 Returns the key from the current position of the hash iterator. See
2150 Perl_hv_iterkey(pTHX_ register HE *entry, I32 *retlen)
2152 if (HeKLEN(entry) == HEf_SVKEY) {
2154 char * const p = SvPV(HeKEY_sv(entry), len);
2159 *retlen = HeKLEN(entry);
2160 return HeKEY(entry);
2164 /* unlike hv_iterval(), this always returns a mortal copy of the key */
2166 =for apidoc hv_iterkeysv
2168 Returns the key as an C<SV*> from the current position of the hash
2169 iterator. The return value will always be a mortal copy of the key. Also
2176 Perl_hv_iterkeysv(pTHX_ register HE *entry)
2178 return sv_2mortal(newSVhek(HeKEY_hek(entry)));
2182 =for apidoc hv_iterval
2184 Returns the value from the current position of the hash iterator. See
2191 Perl_hv_iterval(pTHX_ HV *hv, register HE *entry)
2193 if (SvRMAGICAL(hv)) {
2194 if (mg_find((SV*)hv, PERL_MAGIC_tied)) {
2195 SV* const sv = sv_newmortal();
2196 if (HeKLEN(entry) == HEf_SVKEY)
2197 mg_copy((SV*)hv, sv, (char*)HeKEY_sv(entry), HEf_SVKEY);
2199 mg_copy((SV*)hv, sv, HeKEY(entry), HeKLEN(entry));
2203 return HeVAL(entry);
2207 =for apidoc hv_iternextsv
2209 Performs an C<hv_iternext>, C<hv_iterkey>, and C<hv_iterval> in one
2216 Perl_hv_iternextsv(pTHX_ HV *hv, char **key, I32 *retlen)
2218 HE * const he = hv_iternext_flags(hv, 0);
2222 *key = hv_iterkey(he, retlen);
2223 return hv_iterval(hv, he);
2230 =for apidoc hv_magic
2232 Adds magic to a hash. See C<sv_magic>.
2237 /* possibly free a shared string if no one has access to it
2238 * len and hash must both be valid for str.
2241 Perl_unsharepvn(pTHX_ const char *str, I32 len, U32 hash)
2243 unshare_hek_or_pvn (NULL, str, len, hash);
2248 Perl_unshare_hek(pTHX_ HEK *hek)
2250 unshare_hek_or_pvn(hek, NULL, 0, 0);
2253 /* possibly free a shared string if no one has access to it
2254 hek if non-NULL takes priority over the other 3, else str, len and hash
2255 are used. If so, len and hash must both be valid for str.
2258 S_unshare_hek_or_pvn(pTHX_ const HEK *hek, const char *str, I32 len, U32 hash)
2261 register XPVHV* xhv;
2263 register HE **oentry;
2266 bool is_utf8 = FALSE;
2268 const char * const save = str;
2269 struct shared_he *he = NULL;
2272 /* Find the shared he which is just before us in memory. */
2273 he = (struct shared_he *)(((char *)hek)
2274 - STRUCT_OFFSET(struct shared_he,
2277 /* Assert that the caller passed us a genuine (or at least consistent)
2279 assert (he->shared_he_he.hent_hek == hek);
2282 if (he->shared_he_he.hent_val - 1) {
2283 --he->shared_he_he.hent_val;
2284 UNLOCK_STRTAB_MUTEX;
2287 UNLOCK_STRTAB_MUTEX;
2289 hash = HEK_HASH(hek);
2290 } else if (len < 0) {
2291 STRLEN tmplen = -len;
2293 /* See the note in hv_fetch(). --jhi */
2294 str = (char*)bytes_from_utf8((U8*)str, &tmplen, &is_utf8);
2297 k_flags = HVhek_UTF8;
2299 k_flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
2302 /* what follows is the moral equivalent of:
2303 if ((Svp = hv_fetch(PL_strtab, tmpsv, FALSE, hash))) {
2304 if (--*Svp == Nullsv)
2305 hv_delete(PL_strtab, str, len, G_DISCARD, hash);
2307 xhv = (XPVHV*)SvANY(PL_strtab);
2308 /* assert(xhv_array != 0) */
2310 first = oentry = &(HvARRAY(PL_strtab))[hash & (I32) HvMAX(PL_strtab)];
2312 const HE *const he_he = &(he->shared_he_he);
2313 for (entry = *oentry; entry; oentry = &HeNEXT(entry), entry = *oentry) {
2320 const int flags_masked = k_flags & HVhek_MASK;
2321 for (entry = *oentry; entry; oentry = &HeNEXT(entry), entry = *oentry) {
2322 if (HeHASH(entry) != hash) /* strings can't be equal */
2324 if (HeKLEN(entry) != len)
2326 if (HeKEY(entry) != str && memNE(HeKEY(entry),str,len)) /* is this it? */
2328 if (HeKFLAGS(entry) != flags_masked)
2336 if (--HeVAL(entry) == Nullsv) {
2337 *oentry = HeNEXT(entry);
2339 /* There are now no entries in our slot. */
2340 xhv->xhv_fill--; /* HvFILL(hv)-- */
2343 xhv->xhv_keys--; /* HvKEYS(hv)-- */
2347 UNLOCK_STRTAB_MUTEX;
2348 if (!found && ckWARN_d(WARN_INTERNAL))
2349 Perl_warner(aTHX_ packWARN(WARN_INTERNAL),
2350 "Attempt to free non-existent shared string '%s'%s"
2352 hek ? HEK_KEY(hek) : str,
2353 ((k_flags & HVhek_UTF8) ? " (utf8)" : "") pTHX__VALUE);
2354 if (k_flags & HVhek_FREEKEY)
2358 /* get a (constant) string ptr from the global string table
2359 * string will get added if it is not already there.
2360 * len and hash must both be valid for str.
2363 Perl_share_hek(pTHX_ const char *str, I32 len, register U32 hash)
2365 bool is_utf8 = FALSE;
2367 const char * const save = str;
2370 STRLEN tmplen = -len;
2372 /* See the note in hv_fetch(). --jhi */
2373 str = (char*)bytes_from_utf8((U8*)str, &tmplen, &is_utf8);
2375 /* If we were able to downgrade here, then than means that we were passed
2376 in a key which only had chars 0-255, but was utf8 encoded. */
2379 /* If we found we were able to downgrade the string to bytes, then
2380 we should flag that it needs upgrading on keys or each. Also flag
2381 that we need share_hek_flags to free the string. */
2383 flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
2386 return share_hek_flags (str, len, hash, flags);
2390 S_share_hek_flags(pTHX_ const char *str, I32 len, register U32 hash, int flags)
2394 const int flags_masked = flags & HVhek_MASK;
2395 const U32 hindex = hash & (I32) HvMAX(PL_strtab);
2397 /* what follows is the moral equivalent of:
2399 if (!(Svp = hv_fetch(PL_strtab, str, len, FALSE)))
2400 hv_store(PL_strtab, str, len, Nullsv, hash);
2402 Can't rehash the shared string table, so not sure if it's worth
2403 counting the number of entries in the linked list
2405 register XPVHV * const xhv = (XPVHV*)SvANY(PL_strtab);
2406 /* assert(xhv_array != 0) */
2408 entry = (HvARRAY(PL_strtab))[hindex];
2409 for (;entry; entry = HeNEXT(entry)) {
2410 if (HeHASH(entry) != hash) /* strings can't be equal */
2412 if (HeKLEN(entry) != len)
2414 if (HeKEY(entry) != str && memNE(HeKEY(entry),str,len)) /* is this it? */
2416 if (HeKFLAGS(entry) != flags_masked)
2422 /* What used to be head of the list.
2423 If this is NULL, then we're the first entry for this slot, which
2424 means we need to increate fill. */
2425 struct shared_he *new_entry;
2428 HE **const head = &HvARRAY(PL_strtab)[hindex];
2429 HE *const next = *head;
2431 /* We don't actually store a HE from the arena and a regular HEK.
2432 Instead we allocate one chunk of memory big enough for both,
2433 and put the HEK straight after the HE. This way we can find the
2434 HEK directly from the HE.
2437 Newx(k, STRUCT_OFFSET(struct shared_he,
2438 shared_he_hek.hek_key[0]) + len + 2, char);
2439 new_entry = (struct shared_he *)k;
2440 entry = &(new_entry->shared_he_he);
2441 hek = &(new_entry->shared_he_hek);
2443 Copy(str, HEK_KEY(hek), len, char);
2444 HEK_KEY(hek)[len] = 0;
2446 HEK_HASH(hek) = hash;
2447 HEK_FLAGS(hek) = (unsigned char)flags_masked;
2449 /* Still "point" to the HEK, so that other code need not know what
2451 HeKEY_hek(entry) = hek;
2452 HeVAL(entry) = Nullsv;
2453 HeNEXT(entry) = next;
2456 xhv->xhv_keys++; /* HvKEYS(hv)++ */
2457 if (!next) { /* initial entry? */
2458 xhv->xhv_fill++; /* HvFILL(hv)++ */
2459 } else if (xhv->xhv_keys > (IV)xhv->xhv_max /* HvKEYS(hv) > HvMAX(hv) */) {
2464 ++HeVAL(entry); /* use value slot as REFCNT */
2465 UNLOCK_STRTAB_MUTEX;
2467 if (flags & HVhek_FREEKEY)
2470 return HeKEY_hek(entry);
2474 Perl_hv_placeholders_p(pTHX_ HV *hv)
2477 MAGIC *mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2480 mg = sv_magicext((SV*)hv, 0, PERL_MAGIC_rhash, 0, 0, 0);
2483 Perl_die(aTHX_ "panic: hv_placeholders_p");
2486 return &(mg->mg_len);
2491 Perl_hv_placeholders_get(pTHX_ HV *hv)
2494 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2496 return mg ? mg->mg_len : 0;
2500 Perl_hv_placeholders_set(pTHX_ HV *hv, I32 ph)
2503 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2508 if (!sv_magicext((SV*)hv, 0, PERL_MAGIC_rhash, 0, 0, ph))
2509 Perl_die(aTHX_ "panic: hv_placeholders_set");
2511 /* else we don't need to add magic to record 0 placeholders. */
2515 =for apidoc hv_assert
2517 Check that a hash is in an internally consistent state.
2523 Perl_hv_assert(pTHX_ HV *hv)
2528 int placeholders = 0;
2531 const I32 riter = HvRITER_get(hv);
2532 HE *eiter = HvEITER_get(hv);
2534 (void)hv_iterinit(hv);
2536 while ((entry = hv_iternext_flags(hv, HV_ITERNEXT_WANTPLACEHOLDERS))) {
2537 /* sanity check the values */
2538 if (HeVAL(entry) == &PL_sv_placeholder) {
2543 /* sanity check the keys */
2544 if (HeSVKEY(entry)) {
2545 /* Don't know what to check on SV keys. */
2546 } else if (HeKUTF8(entry)) {
2548 if (HeKWASUTF8(entry)) {
2549 PerlIO_printf(Perl_debug_log,
2550 "hash key has both WASUFT8 and UTF8: '%.*s'\n",
2551 (int) HeKLEN(entry), HeKEY(entry));
2554 } else if (HeKWASUTF8(entry)) {
2558 if (!SvTIED_mg((SV*)hv, PERL_MAGIC_tied)) {
2559 if (HvUSEDKEYS(hv) != real) {
2560 PerlIO_printf(Perl_debug_log, "Count %d key(s), but hash reports %d\n",
2561 (int) real, (int) HvUSEDKEYS(hv));
2564 if (HvPLACEHOLDERS_get(hv) != placeholders) {
2565 PerlIO_printf(Perl_debug_log,
2566 "Count %d placeholder(s), but hash reports %d\n",
2567 (int) placeholders, (int) HvPLACEHOLDERS_get(hv));
2571 if (withflags && ! HvHASKFLAGS(hv)) {
2572 PerlIO_printf(Perl_debug_log,
2573 "Hash has HASKFLAGS off but I count %d key(s) with flags\n",
2580 HvRITER_set(hv, riter); /* Restore hash iterator state */
2581 HvEITER_set(hv, eiter);
2586 * c-indentation-style: bsd
2588 * indent-tabs-mode: t
2591 * ex: set ts=8 sts=4 sw=4 noet: