3 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
4 * 2000, 2001, 2002, 2003, 2004, 2005, 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";
44 Newx(he, PERL_ARENA_SIZE/sizeof(HE), HE);
45 HeNEXT(he) = (HE*) PL_body_arenaroots[HE_SVSLOT];
46 PL_body_arenaroots[HE_SVSLOT] = he;
48 heend = &he[PERL_ARENA_SIZE / sizeof(HE) - 1];
49 PL_body_roots[HE_SVSLOT] = ++he;
51 HeNEXT(he) = (HE*)(he + 1);
59 #define new_HE() (HE*)safemalloc(sizeof(HE))
60 #define del_HE(p) safefree((char*)p)
68 void **root = &PL_body_roots[HE_SVSLOT];
79 #define new_HE() new_he()
83 HeNEXT(p) = (HE*)(PL_body_roots[HE_SVSLOT]); \
84 PL_body_roots[HE_SVSLOT] = p; \
93 S_save_hek_flags(pTHX_ const char *str, I32 len, U32 hash, int flags)
95 const int flags_masked = flags & HVhek_MASK;
99 Newx(k, HEK_BASESIZE + len + 2, char);
101 Copy(str, HEK_KEY(hek), len, char);
102 HEK_KEY(hek)[len] = 0;
104 HEK_HASH(hek) = hash;
105 HEK_FLAGS(hek) = (unsigned char)flags_masked;
107 if (flags & HVhek_FREEKEY)
112 /* free the pool of temporary HE/HEK pairs returned by hv_fetch_ent
116 Perl_free_tied_hv_pool(pTHX)
118 HE *he = PL_hv_fetch_ent_mh;
121 Safefree(HeKEY_hek(he));
125 PL_hv_fetch_ent_mh = Nullhe;
128 #if defined(USE_ITHREADS)
130 Perl_hek_dup(pTHX_ HEK *source, CLONE_PARAMS* param)
132 HEK *shared = (HEK*)ptr_table_fetch(PL_ptr_table, source);
134 PERL_UNUSED_ARG(param);
137 /* We already shared this hash key. */
138 (void)share_hek_hek(shared);
142 = share_hek_flags(HEK_KEY(source), HEK_LEN(source),
143 HEK_HASH(source), HEK_FLAGS(source));
144 ptr_table_store(PL_ptr_table, source, shared);
150 Perl_he_dup(pTHX_ const HE *e, bool shared, CLONE_PARAMS* param)
156 /* look for it in the table first */
157 ret = (HE*)ptr_table_fetch(PL_ptr_table, e);
161 /* create anew and remember what it is */
163 ptr_table_store(PL_ptr_table, e, ret);
165 HeNEXT(ret) = he_dup(HeNEXT(e),shared, param);
166 if (HeKLEN(e) == HEf_SVKEY) {
168 Newx(k, HEK_BASESIZE + sizeof(SV*), char);
169 HeKEY_hek(ret) = (HEK*)k;
170 HeKEY_sv(ret) = SvREFCNT_inc(sv_dup(HeKEY_sv(e), param));
173 /* This is hek_dup inlined, which seems to be important for speed
175 HEK * const source = HeKEY_hek(e);
176 HEK *shared = (HEK*)ptr_table_fetch(PL_ptr_table, source);
179 /* We already shared this hash key. */
180 (void)share_hek_hek(shared);
184 = share_hek_flags(HEK_KEY(source), HEK_LEN(source),
185 HEK_HASH(source), HEK_FLAGS(source));
186 ptr_table_store(PL_ptr_table, source, shared);
188 HeKEY_hek(ret) = shared;
191 HeKEY_hek(ret) = save_hek_flags(HeKEY(e), HeKLEN(e), HeHASH(e),
193 HeVAL(ret) = SvREFCNT_inc(sv_dup(HeVAL(e), param));
196 #endif /* USE_ITHREADS */
199 S_hv_notallowed(pTHX_ int flags, const char *key, I32 klen,
202 SV * const sv = sv_newmortal();
203 if (!(flags & HVhek_FREEKEY)) {
204 sv_setpvn(sv, key, klen);
207 /* Need to free saved eventually assign to mortal SV */
208 /* XXX is this line an error ???: SV *sv = sv_newmortal(); */
209 sv_usepvn(sv, (char *) key, klen);
211 if (flags & HVhek_UTF8) {
214 Perl_croak(aTHX_ msg, sv);
217 /* (klen == HEf_SVKEY) is special for MAGICAL hv entries, meaning key slot
220 #define HV_FETCH_ISSTORE 0x01
221 #define HV_FETCH_ISEXISTS 0x02
222 #define HV_FETCH_LVALUE 0x04
223 #define HV_FETCH_JUST_SV 0x08
228 Stores an SV in a hash. The hash key is specified as C<key> and C<klen> is
229 the length of the key. The C<hash> parameter is the precomputed hash
230 value; if it is zero then Perl will compute it. The return value will be
231 NULL if the operation failed or if the value did not need to be actually
232 stored within the hash (as in the case of tied hashes). Otherwise it can
233 be dereferenced to get the original C<SV*>. Note that the caller is
234 responsible for suitably incrementing the reference count of C<val> before
235 the call, and decrementing it if the function returned NULL. Effectively
236 a successful hv_store takes ownership of one reference to C<val>. This is
237 usually what you want; a newly created SV has a reference count of one, so
238 if all your code does is create SVs then store them in a hash, hv_store
239 will own the only reference to the new SV, and your code doesn't need to do
240 anything further to tidy up. hv_store is not implemented as a call to
241 hv_store_ent, and does not create a temporary SV for the key, so if your
242 key data is not already in SV form then use hv_store in preference to
245 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
246 information on how to use this function on tied hashes.
252 Perl_hv_store(pTHX_ HV *hv, const char *key, I32 klen_i32, SV *val, U32 hash)
265 hek = hv_fetch_common (hv, NULL, key, klen, flags,
266 (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), val, hash);
267 return hek ? &HeVAL(hek) : NULL;
271 Perl_hv_store_flags(pTHX_ HV *hv, const char *key, I32 klen, SV *val,
272 register U32 hash, int flags)
274 HE * const hek = hv_fetch_common (hv, NULL, key, klen, flags,
275 (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), val, hash);
276 return hek ? &HeVAL(hek) : NULL;
280 =for apidoc hv_store_ent
282 Stores C<val> in a hash. The hash key is specified as C<key>. The C<hash>
283 parameter is the precomputed hash value; if it is zero then Perl will
284 compute it. The return value is the new hash entry so created. It will be
285 NULL if the operation failed or if the value did not need to be actually
286 stored within the hash (as in the case of tied hashes). Otherwise the
287 contents of the return value can be accessed using the C<He?> macros
288 described here. Note that the caller is responsible for suitably
289 incrementing the reference count of C<val> before the call, and
290 decrementing it if the function returned NULL. Effectively a successful
291 hv_store_ent takes ownership of one reference to C<val>. This is
292 usually what you want; a newly created SV has a reference count of one, so
293 if all your code does is create SVs then store them in a hash, hv_store
294 will own the only reference to the new SV, and your code doesn't need to do
295 anything further to tidy up. Note that hv_store_ent only reads the C<key>;
296 unlike C<val> it does not take ownership of it, so maintaining the correct
297 reference count on C<key> is entirely the caller's responsibility. hv_store
298 is not implemented as a call to hv_store_ent, and does not create a temporary
299 SV for the key, so if your key data is not already in SV form then use
300 hv_store in preference to hv_store_ent.
302 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
303 information on how to use this function on tied hashes.
309 Perl_hv_store_ent(pTHX_ HV *hv, SV *keysv, SV *val, U32 hash)
311 return hv_fetch_common(hv, keysv, NULL, 0, 0, HV_FETCH_ISSTORE, val, hash);
315 =for apidoc hv_exists
317 Returns a boolean indicating whether the specified hash key exists. The
318 C<klen> is the length of the key.
324 Perl_hv_exists(pTHX_ HV *hv, const char *key, I32 klen_i32)
336 return hv_fetch_common(hv, NULL, key, klen, flags, HV_FETCH_ISEXISTS, 0, 0)
343 Returns the SV which corresponds to the specified key in the hash. The
344 C<klen> is the length of the key. If C<lval> is set then the fetch will be
345 part of a store. Check that the return value is non-null before
346 dereferencing it to an C<SV*>.
348 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
349 information on how to use this function on tied hashes.
355 Perl_hv_fetch(pTHX_ HV *hv, const char *key, I32 klen_i32, I32 lval)
368 hek = hv_fetch_common (hv, NULL, key, klen, flags,
369 HV_FETCH_JUST_SV | (lval ? HV_FETCH_LVALUE : 0),
371 return hek ? &HeVAL(hek) : NULL;
375 =for apidoc hv_exists_ent
377 Returns a boolean indicating whether the specified hash key exists. C<hash>
378 can be a valid precomputed hash value, or 0 to ask for it to be
385 Perl_hv_exists_ent(pTHX_ HV *hv, SV *keysv, U32 hash)
387 return hv_fetch_common(hv, keysv, NULL, 0, 0, HV_FETCH_ISEXISTS, 0, hash)
391 /* returns an HE * structure with the all fields set */
392 /* note that hent_val will be a mortal sv for MAGICAL hashes */
394 =for apidoc hv_fetch_ent
396 Returns the hash entry which corresponds to the specified key in the hash.
397 C<hash> must be a valid precomputed hash number for the given C<key>, or 0
398 if you want the function to compute it. IF C<lval> is set then the fetch
399 will be part of a store. Make sure the return value is non-null before
400 accessing it. The return value when C<tb> is a tied hash is a pointer to a
401 static location, so be sure to make a copy of the structure if you need to
404 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
405 information on how to use this function on tied hashes.
411 Perl_hv_fetch_ent(pTHX_ HV *hv, SV *keysv, I32 lval, register U32 hash)
413 return hv_fetch_common(hv, keysv, NULL, 0, 0,
414 (lval ? HV_FETCH_LVALUE : 0), Nullsv, hash);
418 S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
419 int flags, int action, SV *val, register U32 hash)
433 if (flags & HVhek_FREEKEY)
435 key = SvPV_const(keysv, klen);
437 is_utf8 = (SvUTF8(keysv) != 0);
439 is_utf8 = ((flags & HVhek_UTF8) ? TRUE : FALSE);
442 xhv = (XPVHV*)SvANY(hv);
444 if (SvRMAGICAL(hv) && !(action & (HV_FETCH_ISSTORE|HV_FETCH_ISEXISTS)))
446 if (mg_find((SV*)hv, PERL_MAGIC_tied) || SvGMAGICAL((SV*)hv)) {
449 /* XXX should be able to skimp on the HE/HEK here when
450 HV_FETCH_JUST_SV is true. */
453 keysv = newSVpvn(key, klen);
458 keysv = newSVsv(keysv);
460 mg_copy((SV*)hv, sv, (char *)keysv, HEf_SVKEY);
462 /* grab a fake HE/HEK pair from the pool or make a new one */
463 entry = PL_hv_fetch_ent_mh;
465 PL_hv_fetch_ent_mh = HeNEXT(entry);
469 Newx(k, HEK_BASESIZE + sizeof(SV*), char);
470 HeKEY_hek(entry) = (HEK*)k;
472 HeNEXT(entry) = Nullhe;
473 HeSVKEY_set(entry, keysv);
475 sv_upgrade(sv, SVt_PVLV);
477 /* so we can free entry when freeing sv */
478 LvTARG(sv) = (SV*)entry;
480 /* XXX remove at some point? */
481 if (flags & HVhek_FREEKEY)
486 #ifdef ENV_IS_CASELESS
487 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
489 for (i = 0; i < klen; ++i)
490 if (isLOWER(key[i])) {
491 /* Would be nice if we had a routine to do the
492 copy and upercase in a single pass through. */
493 const char *nkey = strupr(savepvn(key,klen));
494 /* Note that this fetch is for nkey (the uppercased
495 key) whereas the store is for key (the original) */
496 entry = hv_fetch_common(hv, Nullsv, nkey, klen,
497 HVhek_FREEKEY, /* free nkey */
498 0 /* non-LVAL fetch */,
499 Nullsv /* no value */,
500 0 /* compute hash */);
501 if (!entry && (action & HV_FETCH_LVALUE)) {
502 /* This call will free key if necessary.
503 Do it this way to encourage compiler to tail
505 entry = hv_fetch_common(hv, keysv, key, klen,
506 flags, HV_FETCH_ISSTORE,
509 if (flags & HVhek_FREEKEY)
517 else if (SvRMAGICAL(hv) && (action & HV_FETCH_ISEXISTS)) {
518 if (mg_find((SV*)hv, PERL_MAGIC_tied) || SvGMAGICAL((SV*)hv)) {
519 /* I don't understand why hv_exists_ent has svret and sv,
520 whereas hv_exists only had one. */
521 SV * const svret = sv_newmortal();
524 if (keysv || is_utf8) {
526 keysv = newSVpvn(key, klen);
529 keysv = newSVsv(keysv);
531 mg_copy((SV*)hv, sv, (char *)sv_2mortal(keysv), HEf_SVKEY);
533 mg_copy((SV*)hv, sv, key, klen);
535 if (flags & HVhek_FREEKEY)
537 magic_existspack(svret, mg_find(sv, PERL_MAGIC_tiedelem));
538 /* This cast somewhat evil, but I'm merely using NULL/
539 not NULL to return the boolean exists.
540 And I know hv is not NULL. */
541 return SvTRUE(svret) ? (HE *)hv : NULL;
543 #ifdef ENV_IS_CASELESS
544 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
545 /* XXX This code isn't UTF8 clean. */
546 char * const keysave = (char * const)key;
547 /* Will need to free this, so set FREEKEY flag. */
548 key = savepvn(key,klen);
549 key = (const char*)strupr((char*)key);
554 if (flags & HVhek_FREEKEY) {
557 flags |= HVhek_FREEKEY;
561 else if (action & HV_FETCH_ISSTORE) {
564 hv_magic_check (hv, &needs_copy, &needs_store);
566 const bool save_taint = PL_tainted;
567 if (keysv || is_utf8) {
569 keysv = newSVpvn(key, klen);
573 PL_tainted = SvTAINTED(keysv);
574 keysv = sv_2mortal(newSVsv(keysv));
575 mg_copy((SV*)hv, val, (char*)keysv, HEf_SVKEY);
577 mg_copy((SV*)hv, val, key, klen);
580 TAINT_IF(save_taint);
581 if (!HvARRAY(hv) && !needs_store) {
582 if (flags & HVhek_FREEKEY)
586 #ifdef ENV_IS_CASELESS
587 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
588 /* XXX This code isn't UTF8 clean. */
589 const char *keysave = key;
590 /* Will need to free this, so set FREEKEY flag. */
591 key = savepvn(key,klen);
592 key = (const char*)strupr((char*)key);
597 if (flags & HVhek_FREEKEY) {
600 flags |= HVhek_FREEKEY;
608 if ((action & (HV_FETCH_LVALUE | HV_FETCH_ISSTORE))
609 #ifdef DYNAMIC_ENV_FETCH /* if it's an %ENV lookup, we may get it on the fly */
610 || (SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env))
615 PERL_HV_ARRAY_ALLOC_BYTES(xhv->xhv_max+1 /* HvMAX(hv)+1 */),
617 HvARRAY(hv) = (HE**)array;
619 #ifdef DYNAMIC_ENV_FETCH
620 else if (action & HV_FETCH_ISEXISTS) {
621 /* for an %ENV exists, if we do an insert it's by a recursive
622 store call, so avoid creating HvARRAY(hv) right now. */
626 /* XXX remove at some point? */
627 if (flags & HVhek_FREEKEY)
635 char * const keysave = (char * const)key;
636 key = (char*)bytes_from_utf8((U8*)key, &klen, &is_utf8);
640 flags &= ~HVhek_UTF8;
641 if (key != keysave) {
642 if (flags & HVhek_FREEKEY)
644 flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
649 PERL_HASH_INTERNAL(hash, key, klen);
650 /* We don't have a pointer to the hv, so we have to replicate the
651 flag into every HEK, so that hv_iterkeysv can see it. */
652 /* And yes, you do need this even though you are not "storing" because
653 you can flip the flags below if doing an lval lookup. (And that
654 was put in to give the semantics Andreas was expecting.) */
655 flags |= HVhek_REHASH;
657 if (keysv && (SvIsCOW_shared_hash(keysv))) {
658 hash = SvSHARED_HASH(keysv);
660 PERL_HASH(hash, key, klen);
664 masked_flags = (flags & HVhek_MASK);
666 #ifdef DYNAMIC_ENV_FETCH
667 if (!HvARRAY(hv)) entry = Null(HE*);
671 entry = (HvARRAY(hv))[hash & (I32) HvMAX(hv)];
673 for (; entry; entry = HeNEXT(entry)) {
674 if (HeHASH(entry) != hash) /* strings can't be equal */
676 if (HeKLEN(entry) != (I32)klen)
678 if (HeKEY(entry) != key && memNE(HeKEY(entry),key,klen)) /* is this it? */
680 if ((HeKFLAGS(entry) ^ masked_flags) & HVhek_UTF8)
683 if (action & (HV_FETCH_LVALUE|HV_FETCH_ISSTORE)) {
684 if (HeKFLAGS(entry) != masked_flags) {
685 /* We match if HVhek_UTF8 bit in our flags and hash key's
686 match. But if entry was set previously with HVhek_WASUTF8
687 and key now doesn't (or vice versa) then we should change
688 the key's flag, as this is assignment. */
689 if (HvSHAREKEYS(hv)) {
690 /* Need to swap the key we have for a key with the flags we
691 need. As keys are shared we can't just write to the
692 flag, so we share the new one, unshare the old one. */
693 HEK *new_hek = share_hek_flags(key, klen, hash,
695 unshare_hek (HeKEY_hek(entry));
696 HeKEY_hek(entry) = new_hek;
698 else if (hv == PL_strtab) {
699 /* PL_strtab is usually the only hash without HvSHAREKEYS,
700 so putting this test here is cheap */
701 if (flags & HVhek_FREEKEY)
703 Perl_croak(aTHX_ S_strtab_error,
704 action & HV_FETCH_LVALUE ? "fetch" : "store");
707 HeKFLAGS(entry) = masked_flags;
708 if (masked_flags & HVhek_ENABLEHVKFLAGS)
711 if (HeVAL(entry) == &PL_sv_placeholder) {
712 /* yes, can store into placeholder slot */
713 if (action & HV_FETCH_LVALUE) {
715 /* This preserves behaviour with the old hv_fetch
716 implementation which at this point would bail out
717 with a break; (at "if we find a placeholder, we
718 pretend we haven't found anything")
720 That break mean that if a placeholder were found, it
721 caused a call into hv_store, which in turn would
722 check magic, and if there is no magic end up pretty
723 much back at this point (in hv_store's code). */
726 /* LVAL fetch which actaully needs a store. */
728 HvPLACEHOLDERS(hv)--;
731 if (val != &PL_sv_placeholder)
732 HvPLACEHOLDERS(hv)--;
735 } else if (action & HV_FETCH_ISSTORE) {
736 SvREFCNT_dec(HeVAL(entry));
739 } else if (HeVAL(entry) == &PL_sv_placeholder) {
740 /* if we find a placeholder, we pretend we haven't found
744 if (flags & HVhek_FREEKEY)
748 #ifdef DYNAMIC_ENV_FETCH /* %ENV lookup? If so, try to fetch the value now */
749 if (!(action & HV_FETCH_ISSTORE)
750 && SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env)) {
752 const char * const env = PerlEnv_ENVgetenv_len(key,&len);
754 sv = newSVpvn(env,len);
756 return hv_fetch_common(hv,keysv,key,klen,flags,HV_FETCH_ISSTORE,sv,
762 if (!entry && SvREADONLY(hv) && !(action & HV_FETCH_ISEXISTS)) {
763 S_hv_notallowed(aTHX_ flags, key, klen,
764 "Attempt to access disallowed key '%"SVf"' in"
765 " a restricted hash");
767 if (!(action & (HV_FETCH_LVALUE|HV_FETCH_ISSTORE))) {
768 /* Not doing some form of store, so return failure. */
769 if (flags & HVhek_FREEKEY)
773 if (action & HV_FETCH_LVALUE) {
776 /* At this point the old hv_fetch code would call to hv_store,
777 which in turn might do some tied magic. So we need to make that
778 magic check happen. */
779 /* gonna assign to this, so it better be there */
780 return hv_fetch_common(hv, keysv, key, klen, flags,
781 HV_FETCH_ISSTORE, val, hash);
782 /* XXX Surely that could leak if the fetch-was-store fails?
783 Just like the hv_fetch. */
787 /* Welcome to hv_store... */
790 /* Not sure if we can get here. I think the only case of oentry being
791 NULL is for %ENV with dynamic env fetch. But that should disappear
792 with magic in the previous code. */
795 PERL_HV_ARRAY_ALLOC_BYTES(xhv->xhv_max+1 /* HvMAX(hv)+1 */),
797 HvARRAY(hv) = (HE**)array;
800 oentry = &(HvARRAY(hv))[hash & (I32) xhv->xhv_max];
803 /* share_hek_flags will do the free for us. This might be considered
806 HeKEY_hek(entry) = share_hek_flags(key, klen, hash, flags);
807 else if (hv == PL_strtab) {
808 /* PL_strtab is usually the only hash without HvSHAREKEYS, so putting
809 this test here is cheap */
810 if (flags & HVhek_FREEKEY)
812 Perl_croak(aTHX_ S_strtab_error,
813 action & HV_FETCH_LVALUE ? "fetch" : "store");
815 else /* gotta do the real thing */
816 HeKEY_hek(entry) = save_hek_flags(key, klen, hash, flags);
818 HeNEXT(entry) = *oentry;
821 if (val == &PL_sv_placeholder)
822 HvPLACEHOLDERS(hv)++;
823 if (masked_flags & HVhek_ENABLEHVKFLAGS)
827 const HE *counter = HeNEXT(entry);
829 xhv->xhv_keys++; /* HvKEYS(hv)++ */
830 if (!counter) { /* initial entry? */
831 xhv->xhv_fill++; /* HvFILL(hv)++ */
832 } else if (xhv->xhv_keys > (IV)xhv->xhv_max) {
834 } else if(!HvREHASH(hv)) {
837 while ((counter = HeNEXT(counter)))
840 if (n_links > HV_MAX_LENGTH_BEFORE_SPLIT) {
841 /* Use only the old HvKEYS(hv) > HvMAX(hv) condition to limit
842 bucket splits on a rehashed hash, as we're not going to
843 split it again, and if someone is lucky (evil) enough to
844 get all the keys in one list they could exhaust our memory
845 as we repeatedly double the number of buckets on every
846 entry. Linear search feels a less worse thing to do. */
856 S_hv_magic_check(pTHX_ HV *hv, bool *needs_copy, bool *needs_store)
858 const MAGIC *mg = SvMAGIC(hv);
862 if (isUPPER(mg->mg_type)) {
864 if (mg->mg_type == PERL_MAGIC_tied) {
865 *needs_store = FALSE;
866 return; /* We've set all there is to set. */
869 mg = mg->mg_moremagic;
874 =for apidoc hv_scalar
876 Evaluates the hash in scalar context and returns the result. Handles magic when the hash is tied.
882 Perl_hv_scalar(pTHX_ HV *hv)
886 if (SvRMAGICAL(hv)) {
887 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_tied);
889 return magic_scalarpack(hv, mg);
894 Perl_sv_setpvf(aTHX_ sv, "%ld/%ld",
895 (long)HvFILL(hv), (long)HvMAX(hv) + 1);
903 =for apidoc hv_delete
905 Deletes a key/value pair in the hash. The value SV is removed from the
906 hash and returned to the caller. The C<klen> is the length of the key.
907 The C<flags> value will normally be zero; if set to G_DISCARD then NULL
914 Perl_hv_delete(pTHX_ HV *hv, const char *key, I32 klen_i32, I32 flags)
921 k_flags |= HVhek_UTF8;
925 return hv_delete_common(hv, NULL, key, klen, k_flags, flags, 0);
929 =for apidoc hv_delete_ent
931 Deletes a key/value pair in the hash. The value SV is removed from the
932 hash and returned to the caller. The C<flags> value will normally be zero;
933 if set to G_DISCARD then NULL will be returned. C<hash> can be a valid
934 precomputed hash value, or 0 to ask for it to be computed.
940 Perl_hv_delete_ent(pTHX_ HV *hv, SV *keysv, I32 flags, U32 hash)
942 return hv_delete_common(hv, keysv, NULL, 0, 0, flags, hash);
946 S_hv_delete_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
947 int k_flags, I32 d_flags, U32 hash)
952 register HE **oentry;
953 HE *const *first_entry;
962 if (k_flags & HVhek_FREEKEY)
964 key = SvPV_const(keysv, klen);
966 is_utf8 = (SvUTF8(keysv) != 0);
968 is_utf8 = ((k_flags & HVhek_UTF8) ? TRUE : FALSE);
971 if (SvRMAGICAL(hv)) {
974 hv_magic_check (hv, &needs_copy, &needs_store);
977 entry = hv_fetch_common(hv, keysv, key, klen,
978 k_flags & ~HVhek_FREEKEY, HV_FETCH_LVALUE,
980 sv = entry ? HeVAL(entry) : NULL;
986 if (mg_find(sv, PERL_MAGIC_tiedelem)) {
987 /* No longer an element */
988 sv_unmagic(sv, PERL_MAGIC_tiedelem);
991 return Nullsv; /* element cannot be deleted */
993 #ifdef ENV_IS_CASELESS
994 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
995 /* XXX This code isn't UTF8 clean. */
996 keysv = sv_2mortal(newSVpvn(key,klen));
997 if (k_flags & HVhek_FREEKEY) {
1000 key = strupr(SvPVX(keysv));
1009 xhv = (XPVHV*)SvANY(hv);
1014 const char *keysave = key;
1015 key = (char*)bytes_from_utf8((U8*)key, &klen, &is_utf8);
1018 k_flags |= HVhek_UTF8;
1020 k_flags &= ~HVhek_UTF8;
1021 if (key != keysave) {
1022 if (k_flags & HVhek_FREEKEY) {
1023 /* This shouldn't happen if our caller does what we expect,
1024 but strictly the API allows it. */
1027 k_flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
1029 HvHASKFLAGS_on((SV*)hv);
1033 PERL_HASH_INTERNAL(hash, key, klen);
1035 if (keysv && (SvIsCOW_shared_hash(keysv))) {
1036 hash = SvSHARED_HASH(keysv);
1038 PERL_HASH(hash, key, klen);
1042 masked_flags = (k_flags & HVhek_MASK);
1044 first_entry = oentry = &(HvARRAY(hv))[hash & (I32) HvMAX(hv)];
1046 for (; entry; oentry = &HeNEXT(entry), entry = *oentry) {
1047 if (HeHASH(entry) != hash) /* strings can't be equal */
1049 if (HeKLEN(entry) != (I32)klen)
1051 if (HeKEY(entry) != key && memNE(HeKEY(entry),key,klen)) /* is this it? */
1053 if ((HeKFLAGS(entry) ^ masked_flags) & HVhek_UTF8)
1056 if (hv == PL_strtab) {
1057 if (k_flags & HVhek_FREEKEY)
1059 Perl_croak(aTHX_ S_strtab_error, "delete");
1062 /* if placeholder is here, it's already been deleted.... */
1063 if (HeVAL(entry) == &PL_sv_placeholder)
1065 if (k_flags & HVhek_FREEKEY)
1069 else if (SvREADONLY(hv) && HeVAL(entry) && SvREADONLY(HeVAL(entry))) {
1070 S_hv_notallowed(aTHX_ k_flags, key, klen,
1071 "Attempt to delete readonly key '%"SVf"' from"
1072 " a restricted hash");
1074 if (k_flags & HVhek_FREEKEY)
1077 if (d_flags & G_DISCARD)
1080 sv = sv_2mortal(HeVAL(entry));
1081 HeVAL(entry) = &PL_sv_placeholder;
1085 * If a restricted hash, rather than really deleting the entry, put
1086 * a placeholder there. This marks the key as being "approved", so
1087 * we can still access via not-really-existing key without raising
1090 if (SvREADONLY(hv)) {
1091 SvREFCNT_dec(HeVAL(entry));
1092 HeVAL(entry) = &PL_sv_placeholder;
1093 /* We'll be saving this slot, so the number of allocated keys
1094 * doesn't go down, but the number placeholders goes up */
1095 HvPLACEHOLDERS(hv)++;
1097 *oentry = HeNEXT(entry);
1099 xhv->xhv_fill--; /* HvFILL(hv)-- */
1101 if (SvOOK(hv) && entry == HvAUX(hv)->xhv_eiter /* HvEITER(hv) */)
1104 hv_free_ent(hv, entry);
1105 xhv->xhv_keys--; /* HvKEYS(hv)-- */
1106 if (xhv->xhv_keys == 0)
1107 HvHASKFLAGS_off(hv);
1111 if (SvREADONLY(hv)) {
1112 S_hv_notallowed(aTHX_ k_flags, key, klen,
1113 "Attempt to delete disallowed key '%"SVf"' from"
1114 " a restricted hash");
1117 if (k_flags & HVhek_FREEKEY)
1123 S_hsplit(pTHX_ HV *hv)
1125 register XPVHV* xhv = (XPVHV*)SvANY(hv);
1126 const I32 oldsize = (I32) xhv->xhv_max+1; /* HvMAX(hv)+1 (sick) */
1127 register I32 newsize = oldsize * 2;
1129 char *a = (char*) HvARRAY(hv);
1131 register HE **oentry;
1132 int longest_chain = 0;
1135 /*PerlIO_printf(PerlIO_stderr(), "hsplit called for %p which had %d\n",
1136 hv, (int) oldsize);*/
1138 if (HvPLACEHOLDERS_get(hv) && !SvREADONLY(hv)) {
1139 /* Can make this clear any placeholders first for non-restricted hashes,
1140 even though Storable rebuilds restricted hashes by putting in all the
1141 placeholders (first) before turning on the readonly flag, because
1142 Storable always pre-splits the hash. */
1143 hv_clear_placeholders(hv);
1147 #if defined(STRANGE_MALLOC) || defined(MYMALLOC)
1148 Renew(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1149 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1155 Copy(&a[oldsize * sizeof(HE*)], &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1158 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1159 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1164 Copy(HvARRAY(hv), a, oldsize * sizeof(HE*), char);
1166 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1168 if (oldsize >= 64) {
1169 offer_nice_chunk(HvARRAY(hv),
1170 PERL_HV_ARRAY_ALLOC_BYTES(oldsize)
1171 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0));
1174 Safefree(HvARRAY(hv));
1178 Zero(&a[oldsize * sizeof(HE*)], (newsize-oldsize) * sizeof(HE*), char); /* zero 2nd half*/
1179 xhv->xhv_max = --newsize; /* HvMAX(hv) = --newsize */
1180 HvARRAY(hv) = (HE**) a;
1183 for (i=0; i<oldsize; i++,aep++) {
1184 int left_length = 0;
1185 int right_length = 0;
1189 if (!*aep) /* non-existent */
1192 for (oentry = aep, entry = *aep; entry; entry = *oentry) {
1193 if ((HeHASH(entry) & newsize) != (U32)i) {
1194 *oentry = HeNEXT(entry);
1195 HeNEXT(entry) = *bep;
1197 xhv->xhv_fill++; /* HvFILL(hv)++ */
1203 oentry = &HeNEXT(entry);
1207 if (!*aep) /* everything moved */
1208 xhv->xhv_fill--; /* HvFILL(hv)-- */
1209 /* I think we don't actually need to keep track of the longest length,
1210 merely flag if anything is too long. But for the moment while
1211 developing this code I'll track it. */
1212 if (left_length > longest_chain)
1213 longest_chain = left_length;
1214 if (right_length > longest_chain)
1215 longest_chain = right_length;
1219 /* Pick your policy for "hashing isn't working" here: */
1220 if (longest_chain <= HV_MAX_LENGTH_BEFORE_SPLIT /* split worked? */
1225 if (hv == PL_strtab) {
1226 /* Urg. Someone is doing something nasty to the string table.
1231 /* Awooga. Awooga. Pathological data. */
1232 /*PerlIO_printf(PerlIO_stderr(), "%p %d of %d with %d/%d buckets\n", hv,
1233 longest_chain, HvTOTALKEYS(hv), HvFILL(hv), 1+HvMAX(hv));*/
1236 Newxz(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1237 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1239 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1242 was_shared = HvSHAREKEYS(hv);
1245 HvSHAREKEYS_off(hv);
1250 for (i=0; i<newsize; i++,aep++) {
1251 register HE *entry = *aep;
1253 /* We're going to trash this HE's next pointer when we chain it
1254 into the new hash below, so store where we go next. */
1255 HE * const next = HeNEXT(entry);
1260 PERL_HASH_INTERNAL(hash, HeKEY(entry), HeKLEN(entry));
1265 = save_hek_flags(HeKEY(entry), HeKLEN(entry),
1266 hash, HeKFLAGS(entry));
1267 unshare_hek (HeKEY_hek(entry));
1268 HeKEY_hek(entry) = new_hek;
1270 /* Not shared, so simply write the new hash in. */
1271 HeHASH(entry) = hash;
1273 /*PerlIO_printf(PerlIO_stderr(), "%d ", HeKFLAGS(entry));*/
1274 HEK_REHASH_on(HeKEY_hek(entry));
1275 /*PerlIO_printf(PerlIO_stderr(), "%d\n", HeKFLAGS(entry));*/
1277 /* Copy oentry to the correct new chain. */
1278 bep = ((HE**)a) + (hash & (I32) xhv->xhv_max);
1280 xhv->xhv_fill++; /* HvFILL(hv)++ */
1281 HeNEXT(entry) = *bep;
1287 Safefree (HvARRAY(hv));
1288 HvARRAY(hv) = (HE **)a;
1292 Perl_hv_ksplit(pTHX_ HV *hv, IV newmax)
1294 register XPVHV* xhv = (XPVHV*)SvANY(hv);
1295 const I32 oldsize = (I32) xhv->xhv_max+1; /* HvMAX(hv)+1 (sick) */
1296 register I32 newsize;
1301 register HE **oentry;
1303 newsize = (I32) newmax; /* possible truncation here */
1304 if (newsize != newmax || newmax <= oldsize)
1306 while ((newsize & (1 + ~newsize)) != newsize) {
1307 newsize &= ~(newsize & (1 + ~newsize)); /* get proper power of 2 */
1309 if (newsize < newmax)
1311 if (newsize < newmax)
1312 return; /* overflow detection */
1314 a = (char *) HvARRAY(hv);
1317 #if defined(STRANGE_MALLOC) || defined(MYMALLOC)
1318 Renew(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1319 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1325 Copy(&a[oldsize * sizeof(HE*)], &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1328 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize)
1329 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char);
1334 Copy(HvARRAY(hv), a, oldsize * sizeof(HE*), char);
1336 Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux);
1338 if (oldsize >= 64) {
1339 offer_nice_chunk(HvARRAY(hv),
1340 PERL_HV_ARRAY_ALLOC_BYTES(oldsize)
1341 + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0));
1344 Safefree(HvARRAY(hv));
1347 Zero(&a[oldsize * sizeof(HE*)], (newsize-oldsize) * sizeof(HE*), char); /* zero 2nd half*/
1350 Newxz(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize), char);
1352 xhv->xhv_max = --newsize; /* HvMAX(hv) = --newsize */
1353 HvARRAY(hv) = (HE **) a;
1354 if (!xhv->xhv_fill /* !HvFILL(hv) */) /* skip rest if no entries */
1358 for (i=0; i<oldsize; i++,aep++) {
1359 if (!*aep) /* non-existent */
1361 for (oentry = aep, entry = *aep; entry; entry = *oentry) {
1363 if ((j = (HeHASH(entry) & newsize)) != i) {
1365 *oentry = HeNEXT(entry);
1366 if (!(HeNEXT(entry) = aep[j]))
1367 xhv->xhv_fill++; /* HvFILL(hv)++ */
1372 oentry = &HeNEXT(entry);
1374 if (!*aep) /* everything moved */
1375 xhv->xhv_fill--; /* HvFILL(hv)-- */
1382 Creates a new HV. The reference count is set to 1.
1390 register XPVHV* xhv;
1391 HV * const hv = (HV*)NEWSV(502,0);
1393 sv_upgrade((SV *)hv, SVt_PVHV);
1394 xhv = (XPVHV*)SvANY(hv);
1397 #ifndef NODEFAULT_SHAREKEYS
1398 HvSHAREKEYS_on(hv); /* key-sharing on by default */
1401 xhv->xhv_max = 7; /* HvMAX(hv) = 7 (start with 8 buckets) */
1402 xhv->xhv_fill = 0; /* HvFILL(hv) = 0 */
1407 Perl_newHVhv(pTHX_ HV *ohv)
1409 HV * const hv = newHV();
1410 STRLEN hv_max, hv_fill;
1412 if (!ohv || (hv_fill = HvFILL(ohv)) == 0)
1414 hv_max = HvMAX(ohv);
1416 if (!SvMAGICAL((SV *)ohv)) {
1417 /* It's an ordinary hash, so copy it fast. AMS 20010804 */
1419 const bool shared = !!HvSHAREKEYS(ohv);
1420 HE **ents, ** const oents = (HE **)HvARRAY(ohv);
1422 Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(hv_max+1), char);
1425 /* In each bucket... */
1426 for (i = 0; i <= hv_max; i++) {
1427 HE *prev = NULL, *ent = NULL;
1428 HE *oent = oents[i];
1435 /* Copy the linked list of entries. */
1436 for (; oent; oent = HeNEXT(oent)) {
1437 const U32 hash = HeHASH(oent);
1438 const char * const key = HeKEY(oent);
1439 const STRLEN len = HeKLEN(oent);
1440 const int flags = HeKFLAGS(oent);
1443 HeVAL(ent) = newSVsv(HeVAL(oent));
1445 = shared ? share_hek_flags(key, len, hash, flags)
1446 : save_hek_flags(key, len, hash, flags);
1457 HvFILL(hv) = hv_fill;
1458 HvTOTALKEYS(hv) = HvTOTALKEYS(ohv);
1462 /* Iterate over ohv, copying keys and values one at a time. */
1464 const I32 riter = HvRITER_get(ohv);
1465 HE * const eiter = HvEITER_get(ohv);
1467 /* Can we use fewer buckets? (hv_max is always 2^n-1) */
1468 while (hv_max && hv_max + 1 >= hv_fill * 2)
1469 hv_max = hv_max / 2;
1473 while ((entry = hv_iternext_flags(ohv, 0))) {
1474 hv_store_flags(hv, HeKEY(entry), HeKLEN(entry),
1475 newSVsv(HeVAL(entry)), HeHASH(entry),
1478 HvRITER_set(ohv, riter);
1479 HvEITER_set(ohv, eiter);
1486 Perl_hv_free_ent(pTHX_ HV *hv, register HE *entry)
1493 if (val && isGV(val) && GvCVu(val) && HvNAME_get(hv))
1494 PL_sub_generation++; /* may be deletion of method from stash */
1496 if (HeKLEN(entry) == HEf_SVKEY) {
1497 SvREFCNT_dec(HeKEY_sv(entry));
1498 Safefree(HeKEY_hek(entry));
1500 else if (HvSHAREKEYS(hv))
1501 unshare_hek(HeKEY_hek(entry));
1503 Safefree(HeKEY_hek(entry));
1508 Perl_hv_delayfree_ent(pTHX_ HV *hv, register HE *entry)
1512 /* SvREFCNT_inc to counter the SvREFCNT_dec in hv_free_ent */
1513 sv_2mortal(SvREFCNT_inc(HeVAL(entry))); /* free between statements */
1514 if (HeKLEN(entry) == HEf_SVKEY) {
1515 sv_2mortal(SvREFCNT_inc(HeKEY_sv(entry)));
1517 hv_free_ent(hv, entry);
1521 =for apidoc hv_clear
1523 Clears a hash, making it empty.
1529 Perl_hv_clear(pTHX_ HV *hv)
1532 register XPVHV* xhv;
1536 DEBUG_A(Perl_hv_assert(aTHX_ hv));
1538 xhv = (XPVHV*)SvANY(hv);
1540 if (SvREADONLY(hv) && HvARRAY(hv) != NULL) {
1541 /* restricted hash: convert all keys to placeholders */
1543 for (i = 0; i <= xhv->xhv_max; i++) {
1544 HE *entry = (HvARRAY(hv))[i];
1545 for (; entry; entry = HeNEXT(entry)) {
1546 /* not already placeholder */
1547 if (HeVAL(entry) != &PL_sv_placeholder) {
1548 if (HeVAL(entry) && SvREADONLY(HeVAL(entry))) {
1549 SV* keysv = hv_iterkeysv(entry);
1551 "Attempt to delete readonly key '%"SVf"' from a restricted hash",
1554 SvREFCNT_dec(HeVAL(entry));
1555 HeVAL(entry) = &PL_sv_placeholder;
1556 HvPLACEHOLDERS(hv)++;
1564 HvPLACEHOLDERS_set(hv, 0);
1566 (void)memzero(HvARRAY(hv),
1567 (xhv->xhv_max+1 /* HvMAX(hv)+1 */) * sizeof(HE*));
1572 HvHASKFLAGS_off(hv);
1576 HvEITER_set(hv, NULL);
1581 =for apidoc hv_clear_placeholders
1583 Clears any placeholders from a hash. If a restricted hash has any of its keys
1584 marked as readonly and the key is subsequently deleted, the key is not actually
1585 deleted but is marked by assigning it a value of &PL_sv_placeholder. This tags
1586 it so it will be ignored by future operations such as iterating over the hash,
1587 but will still allow the hash to have a value reassigned to the key at some
1588 future point. This function clears any such placeholder keys from the hash.
1589 See Hash::Util::lock_keys() for an example of its use.
1595 Perl_hv_clear_placeholders(pTHX_ HV *hv)
1598 I32 items = (I32)HvPLACEHOLDERS_get(hv);
1606 /* Loop down the linked list heads */
1608 HE **oentry = &(HvARRAY(hv))[i];
1609 HE *entry = *oentry;
1614 for (; entry; entry = *oentry) {
1615 if (HeVAL(entry) == &PL_sv_placeholder) {
1616 *oentry = HeNEXT(entry);
1617 if (first && !*oentry)
1618 HvFILL(hv)--; /* This linked list is now empty. */
1619 if (HvEITER_get(hv))
1622 hv_free_ent(hv, entry);
1626 HvTOTALKEYS(hv) -= (IV)HvPLACEHOLDERS_get(hv);
1627 if (HvKEYS(hv) == 0)
1628 HvHASKFLAGS_off(hv);
1629 HvPLACEHOLDERS_set(hv, 0);
1633 oentry = &HeNEXT(entry);
1638 /* You can't get here, hence assertion should always fail. */
1639 assert (items == 0);
1644 S_hfreeentries(pTHX_ HV *hv)
1646 register HE **array;
1650 struct xpvhv_aux *iter;
1655 iter = SvOOK(hv) ? HvAUX(hv) : 0;
1659 array = HvARRAY(hv);
1660 /* make everyone else think the array is empty, so that the destructors
1661 * called for freed entries can't recusively mess with us */
1662 HvARRAY(hv) = Null(HE**);
1663 SvFLAGS(hv) &= ~SVf_OOK;
1666 ((XPVHV*) SvANY(hv))->xhv_keys = 0;
1671 register HE * const oentry = entry;
1672 entry = HeNEXT(entry);
1673 hv_free_ent(hv, oentry);
1678 entry = array[riter];
1683 /* Someone attempted to iterate or set the hash name while we had
1684 the array set to 0. */
1685 assert(HvARRAY(hv));
1687 if (HvAUX(hv)->xhv_name)
1688 unshare_hek_or_pvn(HvAUX(hv)->xhv_name, 0, 0, 0);
1689 /* SvOOK_off calls sv_backoff, which isn't correct. */
1691 Safefree(HvARRAY(hv));
1693 SvFLAGS(hv) &= ~SVf_OOK;
1696 /* FIXME - things will still go horribly wrong (or at least leak) if
1697 people attempt to add elements to the hash while we're undef()ing it */
1699 entry = iter->xhv_eiter; /* HvEITER(hv) */
1700 if (entry && HvLAZYDEL(hv)) { /* was deleted earlier? */
1702 hv_free_ent(hv, entry);
1704 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1705 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1706 SvFLAGS(hv) |= SVf_OOK;
1709 HvARRAY(hv) = array;
1713 =for apidoc hv_undef
1721 Perl_hv_undef(pTHX_ HV *hv)
1723 register XPVHV* xhv;
1727 DEBUG_A(Perl_hv_assert(aTHX_ hv));
1728 xhv = (XPVHV*)SvANY(hv);
1730 if ((name = HvNAME_get(hv))) {
1732 hv_delete(PL_stashcache, name, HvNAMELEN_get(hv), G_DISCARD);
1733 hv_name_set(hv, Nullch, 0, 0);
1735 SvFLAGS(hv) &= ~SVf_OOK;
1736 Safefree(HvARRAY(hv));
1737 xhv->xhv_max = 7; /* HvMAX(hv) = 7 (it's a normal hash) */
1739 HvPLACEHOLDERS_set(hv, 0);
1745 static struct xpvhv_aux*
1746 S_hv_auxinit(pTHX_ HV *hv) {
1747 struct xpvhv_aux *iter;
1751 Newxz(array, PERL_HV_ARRAY_ALLOC_BYTES(HvMAX(hv) + 1)
1752 + sizeof(struct xpvhv_aux), char);
1754 array = (char *) HvARRAY(hv);
1755 Renew(array, PERL_HV_ARRAY_ALLOC_BYTES(HvMAX(hv) + 1)
1756 + sizeof(struct xpvhv_aux), char);
1758 HvARRAY(hv) = (HE**) array;
1759 /* SvOOK_on(hv) attacks the IV flags. */
1760 SvFLAGS(hv) |= SVf_OOK;
1763 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1764 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1771 =for apidoc hv_iterinit
1773 Prepares a starting point to traverse a hash table. Returns the number of
1774 keys in the hash (i.e. the same as C<HvKEYS(tb)>). The return value is
1775 currently only meaningful for hashes without tie magic.
1777 NOTE: Before version 5.004_65, C<hv_iterinit> used to return the number of
1778 hash buckets that happen to be in use. If you still need that esoteric
1779 value, you can get it through the macro C<HvFILL(tb)>.
1786 Perl_hv_iterinit(pTHX_ HV *hv)
1791 Perl_croak(aTHX_ "Bad hash");
1794 struct xpvhv_aux *iter = HvAUX(hv);
1795 entry = iter->xhv_eiter; /* HvEITER(hv) */
1796 if (entry && HvLAZYDEL(hv)) { /* was deleted earlier? */
1798 hv_free_ent(hv, entry);
1800 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1801 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1803 S_hv_auxinit(aTHX_ hv);
1806 /* used to be xhv->xhv_fill before 5.004_65 */
1807 return HvTOTALKEYS(hv);
1811 Perl_hv_riter_p(pTHX_ HV *hv) {
1812 struct xpvhv_aux *iter;
1815 Perl_croak(aTHX_ "Bad hash");
1817 iter = SvOOK(hv) ? HvAUX(hv) : S_hv_auxinit(aTHX_ hv);
1818 return &(iter->xhv_riter);
1822 Perl_hv_eiter_p(pTHX_ HV *hv) {
1823 struct xpvhv_aux *iter;
1826 Perl_croak(aTHX_ "Bad hash");
1828 iter = SvOOK(hv) ? HvAUX(hv) : S_hv_auxinit(aTHX_ hv);
1829 return &(iter->xhv_eiter);
1833 Perl_hv_riter_set(pTHX_ HV *hv, I32 riter) {
1834 struct xpvhv_aux *iter;
1837 Perl_croak(aTHX_ "Bad hash");
1845 iter = S_hv_auxinit(aTHX_ hv);
1847 iter->xhv_riter = riter;
1851 Perl_hv_eiter_set(pTHX_ HV *hv, HE *eiter) {
1852 struct xpvhv_aux *iter;
1855 Perl_croak(aTHX_ "Bad hash");
1860 /* 0 is the default so don't go malloc()ing a new structure just to
1865 iter = S_hv_auxinit(aTHX_ hv);
1867 iter->xhv_eiter = eiter;
1871 Perl_hv_name_set(pTHX_ HV *hv, const char *name, I32 len, int flags)
1873 struct xpvhv_aux *iter;
1876 PERL_UNUSED_ARG(flags);
1880 if (iter->xhv_name) {
1881 unshare_hek_or_pvn(iter->xhv_name, 0, 0, 0);
1887 iter = S_hv_auxinit(aTHX_ hv);
1889 PERL_HASH(hash, name, len);
1890 iter->xhv_name = name ? share_hek(name, len, hash) : 0;
1894 hv_iternext is implemented as a macro in hv.h
1896 =for apidoc hv_iternext
1898 Returns entries from a hash iterator. See C<hv_iterinit>.
1900 You may call C<hv_delete> or C<hv_delete_ent> on the hash entry that the
1901 iterator currently points to, without losing your place or invalidating your
1902 iterator. Note that in this case the current entry is deleted from the hash
1903 with your iterator holding the last reference to it. Your iterator is flagged
1904 to free the entry on the next call to C<hv_iternext>, so you must not discard
1905 your iterator immediately else the entry will leak - call C<hv_iternext> to
1906 trigger the resource deallocation.
1908 =for apidoc hv_iternext_flags
1910 Returns entries from a hash iterator. See C<hv_iterinit> and C<hv_iternext>.
1911 The C<flags> value will normally be zero; if HV_ITERNEXT_WANTPLACEHOLDERS is
1912 set the placeholders keys (for restricted hashes) will be returned in addition
1913 to normal keys. By default placeholders are automatically skipped over.
1914 Currently a placeholder is implemented with a value that is
1915 C<&Perl_sv_placeholder>. Note that the implementation of placeholders and
1916 restricted hashes may change, and the implementation currently is
1917 insufficiently abstracted for any change to be tidy.
1923 Perl_hv_iternext_flags(pTHX_ HV *hv, I32 flags)
1926 register XPVHV* xhv;
1930 struct xpvhv_aux *iter;
1933 Perl_croak(aTHX_ "Bad hash");
1934 xhv = (XPVHV*)SvANY(hv);
1937 /* Too many things (well, pp_each at least) merrily assume that you can
1938 call iv_iternext without calling hv_iterinit, so we'll have to deal
1944 oldentry = entry = iter->xhv_eiter; /* HvEITER(hv) */
1946 if ((mg = SvTIED_mg((SV*)hv, PERL_MAGIC_tied))) {
1947 SV * const key = sv_newmortal();
1949 sv_setsv(key, HeSVKEY_force(entry));
1950 SvREFCNT_dec(HeSVKEY(entry)); /* get rid of previous key */
1956 /* one HE per MAGICAL hash */
1957 iter->xhv_eiter = entry = new_HE(); /* HvEITER(hv) = new_HE() */
1959 Newxz(k, HEK_BASESIZE + sizeof(SV*), char);
1961 HeKEY_hek(entry) = hek;
1962 HeKLEN(entry) = HEf_SVKEY;
1964 magic_nextpack((SV*) hv,mg,key);
1966 /* force key to stay around until next time */
1967 HeSVKEY_set(entry, SvREFCNT_inc(key));
1968 return entry; /* beware, hent_val is not set */
1971 SvREFCNT_dec(HeVAL(entry));
1972 Safefree(HeKEY_hek(entry));
1974 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1977 #ifdef DYNAMIC_ENV_FETCH /* set up %ENV for iteration */
1978 if (!entry && SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env)) {
1981 /* The prime_env_iter() on VMS just loaded up new hash values
1982 * so the iteration count needs to be reset back to the beginning
1986 oldentry = entry = iter->xhv_eiter; /* HvEITER(hv) */
1991 /* hv_iterint now ensures this. */
1992 assert (HvARRAY(hv));
1994 /* At start of hash, entry is NULL. */
1997 entry = HeNEXT(entry);
1998 if (!(flags & HV_ITERNEXT_WANTPLACEHOLDERS)) {
2000 * Skip past any placeholders -- don't want to include them in
2003 while (entry && HeVAL(entry) == &PL_sv_placeholder) {
2004 entry = HeNEXT(entry);
2009 /* OK. Come to the end of the current list. Grab the next one. */
2011 iter->xhv_riter++; /* HvRITER(hv)++ */
2012 if (iter->xhv_riter > (I32)xhv->xhv_max /* HvRITER(hv) > HvMAX(hv) */) {
2013 /* There is no next one. End of the hash. */
2014 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
2017 entry = (HvARRAY(hv))[iter->xhv_riter];
2019 if (!(flags & HV_ITERNEXT_WANTPLACEHOLDERS)) {
2020 /* If we have an entry, but it's a placeholder, don't count it.
2022 while (entry && HeVAL(entry) == &PL_sv_placeholder)
2023 entry = HeNEXT(entry);
2025 /* Will loop again if this linked list starts NULL
2026 (for HV_ITERNEXT_WANTPLACEHOLDERS)
2027 or if we run through it and find only placeholders. */
2030 if (oldentry && HvLAZYDEL(hv)) { /* was deleted earlier? */
2032 hv_free_ent(hv, oldentry);
2035 /*if (HvREHASH(hv) && entry && !HeKREHASH(entry))
2036 PerlIO_printf(PerlIO_stderr(), "Awooga %p %p\n", hv, entry);*/
2038 iter->xhv_eiter = entry; /* HvEITER(hv) = entry */
2043 =for apidoc hv_iterkey
2045 Returns the key from the current position of the hash iterator. See
2052 Perl_hv_iterkey(pTHX_ register HE *entry, I32 *retlen)
2054 if (HeKLEN(entry) == HEf_SVKEY) {
2056 char *p = SvPV(HeKEY_sv(entry), len);
2061 *retlen = HeKLEN(entry);
2062 return HeKEY(entry);
2066 /* unlike hv_iterval(), this always returns a mortal copy of the key */
2068 =for apidoc hv_iterkeysv
2070 Returns the key as an C<SV*> from the current position of the hash
2071 iterator. The return value will always be a mortal copy of the key. Also
2078 Perl_hv_iterkeysv(pTHX_ register HE *entry)
2080 return sv_2mortal(newSVhek(HeKEY_hek(entry)));
2084 =for apidoc hv_iterval
2086 Returns the value from the current position of the hash iterator. See
2093 Perl_hv_iterval(pTHX_ HV *hv, register HE *entry)
2095 if (SvRMAGICAL(hv)) {
2096 if (mg_find((SV*)hv, PERL_MAGIC_tied)) {
2097 SV* const sv = sv_newmortal();
2098 if (HeKLEN(entry) == HEf_SVKEY)
2099 mg_copy((SV*)hv, sv, (char*)HeKEY_sv(entry), HEf_SVKEY);
2101 mg_copy((SV*)hv, sv, HeKEY(entry), HeKLEN(entry));
2105 return HeVAL(entry);
2109 =for apidoc hv_iternextsv
2111 Performs an C<hv_iternext>, C<hv_iterkey>, and C<hv_iterval> in one
2118 Perl_hv_iternextsv(pTHX_ HV *hv, char **key, I32 *retlen)
2121 if ( (he = hv_iternext_flags(hv, 0)) == NULL)
2123 *key = hv_iterkey(he, retlen);
2124 return hv_iterval(hv, he);
2131 =for apidoc hv_magic
2133 Adds magic to a hash. See C<sv_magic>.
2138 /* possibly free a shared string if no one has access to it
2139 * len and hash must both be valid for str.
2142 Perl_unsharepvn(pTHX_ const char *str, I32 len, U32 hash)
2144 unshare_hek_or_pvn (NULL, str, len, hash);
2149 Perl_unshare_hek(pTHX_ HEK *hek)
2151 unshare_hek_or_pvn(hek, NULL, 0, 0);
2154 /* possibly free a shared string if no one has access to it
2155 hek if non-NULL takes priority over the other 3, else str, len and hash
2156 are used. If so, len and hash must both be valid for str.
2159 S_unshare_hek_or_pvn(pTHX_ const HEK *hek, const char *str, I32 len, U32 hash)
2161 register XPVHV* xhv;
2163 register HE **oentry;
2166 bool is_utf8 = FALSE;
2168 const char * const save = str;
2169 struct shared_he *he = 0;
2172 /* Find the shared he which is just before us in memory. */
2173 he = (struct shared_he *)(((char *)hek)
2174 - STRUCT_OFFSET(struct shared_he,
2177 /* Assert that the caller passed us a genuine (or at least consistent)
2179 assert (he->shared_he_he.hent_hek == hek);
2182 if (he->shared_he_he.hent_val - 1) {
2183 --he->shared_he_he.hent_val;
2184 UNLOCK_STRTAB_MUTEX;
2187 UNLOCK_STRTAB_MUTEX;
2189 hash = HEK_HASH(hek);
2190 } else if (len < 0) {
2191 STRLEN tmplen = -len;
2193 /* See the note in hv_fetch(). --jhi */
2194 str = (char*)bytes_from_utf8((U8*)str, &tmplen, &is_utf8);
2197 k_flags = HVhek_UTF8;
2199 k_flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
2202 /* what follows is the moral equivalent of:
2203 if ((Svp = hv_fetch(PL_strtab, tmpsv, FALSE, hash))) {
2204 if (--*Svp == Nullsv)
2205 hv_delete(PL_strtab, str, len, G_DISCARD, hash);
2207 xhv = (XPVHV*)SvANY(PL_strtab);
2208 /* assert(xhv_array != 0) */
2210 first = oentry = &(HvARRAY(PL_strtab))[hash & (I32) HvMAX(PL_strtab)];
2212 const HE *const he_he = &(he->shared_he_he);
2213 for (entry = *oentry; entry; oentry = &HeNEXT(entry), entry = *oentry) {
2220 const int flags_masked = k_flags & HVhek_MASK;
2221 for (entry = *oentry; entry; oentry = &HeNEXT(entry), entry = *oentry) {
2222 if (HeHASH(entry) != hash) /* strings can't be equal */
2224 if (HeKLEN(entry) != len)
2226 if (HeKEY(entry) != str && memNE(HeKEY(entry),str,len)) /* is this it? */
2228 if (HeKFLAGS(entry) != flags_masked)
2236 if (--HeVAL(entry) == Nullsv) {
2237 *oentry = HeNEXT(entry);
2239 /* There are now no entries in our slot. */
2240 xhv->xhv_fill--; /* HvFILL(hv)-- */
2243 xhv->xhv_keys--; /* HvKEYS(hv)-- */
2247 UNLOCK_STRTAB_MUTEX;
2248 if (!found && ckWARN_d(WARN_INTERNAL))
2249 Perl_warner(aTHX_ packWARN(WARN_INTERNAL),
2250 "Attempt to free non-existent shared string '%s'%s"
2252 hek ? HEK_KEY(hek) : str,
2253 ((k_flags & HVhek_UTF8) ? " (utf8)" : "") pTHX__VALUE);
2254 if (k_flags & HVhek_FREEKEY)
2258 /* get a (constant) string ptr from the global string table
2259 * string will get added if it is not already there.
2260 * len and hash must both be valid for str.
2263 Perl_share_hek(pTHX_ const char *str, I32 len, register U32 hash)
2265 bool is_utf8 = FALSE;
2267 const char * const save = str;
2270 STRLEN tmplen = -len;
2272 /* See the note in hv_fetch(). --jhi */
2273 str = (char*)bytes_from_utf8((U8*)str, &tmplen, &is_utf8);
2275 /* If we were able to downgrade here, then than means that we were passed
2276 in a key which only had chars 0-255, but was utf8 encoded. */
2279 /* If we found we were able to downgrade the string to bytes, then
2280 we should flag that it needs upgrading on keys or each. Also flag
2281 that we need share_hek_flags to free the string. */
2283 flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
2286 return share_hek_flags (str, len, hash, flags);
2290 S_share_hek_flags(pTHX_ const char *str, I32 len, register U32 hash, int flags)
2293 register HE **oentry;
2295 const int flags_masked = flags & HVhek_MASK;
2297 /* what follows is the moral equivalent of:
2299 if (!(Svp = hv_fetch(PL_strtab, str, len, FALSE)))
2300 hv_store(PL_strtab, str, len, Nullsv, hash);
2302 Can't rehash the shared string table, so not sure if it's worth
2303 counting the number of entries in the linked list
2305 register XPVHV * const xhv = (XPVHV*)SvANY(PL_strtab);
2306 /* assert(xhv_array != 0) */
2308 oentry = &(HvARRAY(PL_strtab))[hash & (I32) HvMAX(PL_strtab)];
2309 for (entry = *oentry; entry; entry = HeNEXT(entry)) {
2310 if (HeHASH(entry) != hash) /* strings can't be equal */
2312 if (HeKLEN(entry) != len)
2314 if (HeKEY(entry) != str && memNE(HeKEY(entry),str,len)) /* is this it? */
2316 if (HeKFLAGS(entry) != flags_masked)
2322 /* What used to be head of the list.
2323 If this is NULL, then we're the first entry for this slot, which
2324 means we need to increate fill. */
2325 const HE *old_first = *oentry;
2326 struct shared_he *new_entry;
2330 /* We don't actually store a HE from the arena and a regular HEK.
2331 Instead we allocate one chunk of memory big enough for both,
2332 and put the HEK straight after the HE. This way we can find the
2333 HEK directly from the HE.
2336 Newx(k, STRUCT_OFFSET(struct shared_he,
2337 shared_he_hek.hek_key[0]) + len + 2, char);
2338 new_entry = (struct shared_he *)k;
2339 entry = &(new_entry->shared_he_he);
2340 hek = &(new_entry->shared_he_hek);
2342 Copy(str, HEK_KEY(hek), len, char);
2343 HEK_KEY(hek)[len] = 0;
2345 HEK_HASH(hek) = hash;
2346 HEK_FLAGS(hek) = (unsigned char)flags_masked;
2348 /* Still "point" to the HEK, so that other code need not know what
2350 HeKEY_hek(entry) = hek;
2351 HeVAL(entry) = Nullsv;
2352 HeNEXT(entry) = *oentry;
2355 xhv->xhv_keys++; /* HvKEYS(hv)++ */
2356 if (!old_first) { /* initial entry? */
2357 xhv->xhv_fill++; /* HvFILL(hv)++ */
2358 } else if (xhv->xhv_keys > (IV)xhv->xhv_max /* HvKEYS(hv) > HvMAX(hv) */) {
2363 ++HeVAL(entry); /* use value slot as REFCNT */
2364 UNLOCK_STRTAB_MUTEX;
2366 if (flags & HVhek_FREEKEY)
2369 return HeKEY_hek(entry);
2373 Perl_hv_placeholders_p(pTHX_ HV *hv)
2376 MAGIC *mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2379 mg = sv_magicext((SV*)hv, 0, PERL_MAGIC_rhash, 0, 0, 0);
2382 Perl_die(aTHX_ "panic: hv_placeholders_p");
2385 return &(mg->mg_len);
2390 Perl_hv_placeholders_get(pTHX_ HV *hv)
2393 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2395 return mg ? mg->mg_len : 0;
2399 Perl_hv_placeholders_set(pTHX_ HV *hv, I32 ph)
2402 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2407 if (!sv_magicext((SV*)hv, 0, PERL_MAGIC_rhash, 0, 0, ph))
2408 Perl_die(aTHX_ "panic: hv_placeholders_set");
2410 /* else we don't need to add magic to record 0 placeholders. */
2414 =for apidoc hv_assert
2416 Check that a hash is in an internally consistent state.
2422 Perl_hv_assert(pTHX_ HV *hv)
2427 int placeholders = 0;
2430 const I32 riter = HvRITER_get(hv);
2431 HE *eiter = HvEITER_get(hv);
2433 (void)hv_iterinit(hv);
2435 while ((entry = hv_iternext_flags(hv, HV_ITERNEXT_WANTPLACEHOLDERS))) {
2436 /* sanity check the values */
2437 if (HeVAL(entry) == &PL_sv_placeholder) {
2442 /* sanity check the keys */
2443 if (HeSVKEY(entry)) {
2444 /* Don't know what to check on SV keys. */
2445 } else if (HeKUTF8(entry)) {
2447 if (HeKWASUTF8(entry)) {
2448 PerlIO_printf(Perl_debug_log,
2449 "hash key has both WASUFT8 and UTF8: '%.*s'\n",
2450 (int) HeKLEN(entry), HeKEY(entry));
2453 } else if (HeKWASUTF8(entry)) {
2457 if (!SvTIED_mg((SV*)hv, PERL_MAGIC_tied)) {
2458 if (HvUSEDKEYS(hv) != real) {
2459 PerlIO_printf(Perl_debug_log, "Count %d key(s), but hash reports %d\n",
2460 (int) real, (int) HvUSEDKEYS(hv));
2463 if (HvPLACEHOLDERS_get(hv) != placeholders) {
2464 PerlIO_printf(Perl_debug_log,
2465 "Count %d placeholder(s), but hash reports %d\n",
2466 (int) placeholders, (int) HvPLACEHOLDERS_get(hv));
2470 if (withflags && ! HvHASKFLAGS(hv)) {
2471 PerlIO_printf(Perl_debug_log,
2472 "Hash has HASKFLAGS off but I count %d key(s) with flags\n",
2479 HvRITER_set(hv, riter); /* Restore hash iterator state */
2480 HvEITER_set(hv, eiter);
2485 * c-indentation-style: bsd
2487 * indent-tabs-mode: t
2490 * ex: set ts=8 sts=4 sw=4 noet: