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) = PL_he_arenaroot;
48 heend = &he[PERL_ARENA_SIZE / sizeof(HE) - 1];
51 HeNEXT(he) = (HE*)(he + 1);
59 #define new_HE() (HE*)safemalloc(sizeof(HE))
60 #define del_HE(p) safefree((char*)p)
72 PL_he_root = HeNEXT(he);
77 #define new_HE() new_he()
81 HeNEXT(p) = (HE*)PL_he_root; \
91 S_save_hek_flags(pTHX_ const char *str, I32 len, U32 hash, int flags)
93 const int flags_masked = flags & HVhek_MASK;
97 Newx(k, HEK_BASESIZE + len + 2, char);
99 Copy(str, HEK_KEY(hek), len, char);
100 HEK_KEY(hek)[len] = 0;
102 HEK_HASH(hek) = hash;
103 HEK_FLAGS(hek) = (unsigned char)flags_masked;
105 if (flags & HVhek_FREEKEY)
110 /* free the pool of temporary HE/HEK pairs retunrned by hv_fetch_ent
114 Perl_free_tied_hv_pool(pTHX)
116 HE *he = PL_hv_fetch_ent_mh;
119 Safefree(HeKEY_hek(he));
123 PL_hv_fetch_ent_mh = Nullhe;
126 #if defined(USE_ITHREADS)
128 Perl_hek_dup(pTHX_ HEK *source, CLONE_PARAMS* param)
130 HEK *shared = (HEK*)ptr_table_fetch(PL_ptr_table, source);
132 PERL_UNUSED_ARG(param);
135 /* We already shared this hash key. */
136 (void)share_hek_hek(shared);
140 = share_hek_flags(HEK_KEY(source), HEK_LEN(source),
141 HEK_HASH(source), HEK_FLAGS(source));
142 ptr_table_store(PL_ptr_table, source, shared);
148 Perl_he_dup(pTHX_ HE *e, bool shared, CLONE_PARAMS* param)
154 /* look for it in the table first */
155 ret = (HE*)ptr_table_fetch(PL_ptr_table, e);
159 /* create anew and remember what it is */
161 ptr_table_store(PL_ptr_table, e, ret);
163 HeNEXT(ret) = he_dup(HeNEXT(e),shared, param);
164 if (HeKLEN(e) == HEf_SVKEY) {
166 Newx(k, HEK_BASESIZE + sizeof(SV*), char);
167 HeKEY_hek(ret) = (HEK*)k;
168 HeKEY_sv(ret) = SvREFCNT_inc(sv_dup(HeKEY_sv(e), param));
171 /* This is hek_dup inlined, which seems to be important for speed
173 HEK * const source = HeKEY_hek(e);
174 HEK *shared = (HEK*)ptr_table_fetch(PL_ptr_table, source);
177 /* We already shared this hash key. */
178 (void)share_hek_hek(shared);
182 = share_hek_flags(HEK_KEY(source), HEK_LEN(source),
183 HEK_HASH(source), HEK_FLAGS(source));
184 ptr_table_store(PL_ptr_table, source, shared);
186 HeKEY_hek(ret) = shared;
189 HeKEY_hek(ret) = save_hek_flags(HeKEY(e), HeKLEN(e), HeHASH(e),
191 HeVAL(ret) = SvREFCNT_inc(sv_dup(HeVAL(e), param));
194 #endif /* USE_ITHREADS */
197 S_hv_notallowed(pTHX_ int flags, const char *key, I32 klen,
200 SV * const sv = sv_newmortal();
201 if (!(flags & HVhek_FREEKEY)) {
202 sv_setpvn(sv, key, klen);
205 /* Need to free saved eventually assign to mortal SV */
206 /* XXX is this line an error ???: SV *sv = sv_newmortal(); */
207 sv_usepvn(sv, (char *) key, klen);
209 if (flags & HVhek_UTF8) {
212 Perl_croak(aTHX_ msg, sv);
215 /* (klen == HEf_SVKEY) is special for MAGICAL hv entries, meaning key slot
218 #define HV_FETCH_ISSTORE 0x01
219 #define HV_FETCH_ISEXISTS 0x02
220 #define HV_FETCH_LVALUE 0x04
221 #define HV_FETCH_JUST_SV 0x08
226 Stores an SV in a hash. The hash key is specified as C<key> and C<klen> is
227 the length of the key. The C<hash> parameter is the precomputed hash
228 value; if it is zero then Perl will compute it. The return value will be
229 NULL if the operation failed or if the value did not need to be actually
230 stored within the hash (as in the case of tied hashes). Otherwise it can
231 be dereferenced to get the original C<SV*>. Note that the caller is
232 responsible for suitably incrementing the reference count of C<val> before
233 the call, and decrementing it if the function returned NULL. Effectively
234 a successful hv_store takes ownership of one reference to C<val>. This is
235 usually what you want; a newly created SV has a reference count of one, so
236 if all your code does is create SVs then store them in a hash, hv_store
237 will own the only reference to the new SV, and your code doesn't need to do
238 anything further to tidy up. hv_store is not implemented as a call to
239 hv_store_ent, and does not create a temporary SV for the key, so if your
240 key data is not already in SV form then use hv_store in preference to
243 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
244 information on how to use this function on tied hashes.
250 Perl_hv_store(pTHX_ HV *hv, const char *key, I32 klen_i32, SV *val, U32 hash)
263 hek = hv_fetch_common (hv, NULL, key, klen, flags,
264 (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), val, hash);
265 return hek ? &HeVAL(hek) : NULL;
269 Perl_hv_store_flags(pTHX_ HV *hv, const char *key, I32 klen, SV *val,
270 register U32 hash, int flags)
272 HE * const hek = hv_fetch_common (hv, NULL, key, klen, flags,
273 (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), val, hash);
274 return hek ? &HeVAL(hek) : NULL;
278 =for apidoc hv_store_ent
280 Stores C<val> in a hash. The hash key is specified as C<key>. The C<hash>
281 parameter is the precomputed hash value; if it is zero then Perl will
282 compute it. The return value is the new hash entry so created. It will be
283 NULL if the operation failed or if the value did not need to be actually
284 stored within the hash (as in the case of tied hashes). Otherwise the
285 contents of the return value can be accessed using the C<He?> macros
286 described here. Note that the caller is responsible for suitably
287 incrementing the reference count of C<val> before the call, and
288 decrementing it if the function returned NULL. Effectively a successful
289 hv_store_ent takes ownership of one reference to C<val>. This is
290 usually what you want; a newly created SV has a reference count of one, so
291 if all your code does is create SVs then store them in a hash, hv_store
292 will own the only reference to the new SV, and your code doesn't need to do
293 anything further to tidy up. Note that hv_store_ent only reads the C<key>;
294 unlike C<val> it does not take ownership of it, so maintaining the correct
295 reference count on C<key> is entirely the caller's responsibility. hv_store
296 is not implemented as a call to hv_store_ent, and does not create a temporary
297 SV for the key, so if your key data is not already in SV form then use
298 hv_store in preference to hv_store_ent.
300 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
301 information on how to use this function on tied hashes.
307 Perl_hv_store_ent(pTHX_ HV *hv, SV *keysv, SV *val, U32 hash)
309 return hv_fetch_common(hv, keysv, NULL, 0, 0, HV_FETCH_ISSTORE, val, hash);
313 =for apidoc hv_exists
315 Returns a boolean indicating whether the specified hash key exists. The
316 C<klen> is the length of the key.
322 Perl_hv_exists(pTHX_ HV *hv, const char *key, I32 klen_i32)
334 return hv_fetch_common(hv, NULL, key, klen, flags, HV_FETCH_ISEXISTS, 0, 0)
341 Returns the SV which corresponds to the specified key in the hash. The
342 C<klen> is the length of the key. If C<lval> is set then the fetch will be
343 part of a store. Check that the return value is non-null before
344 dereferencing it to an C<SV*>.
346 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
347 information on how to use this function on tied hashes.
353 Perl_hv_fetch(pTHX_ HV *hv, const char *key, I32 klen_i32, I32 lval)
366 hek = hv_fetch_common (hv, NULL, key, klen, flags,
367 HV_FETCH_JUST_SV | (lval ? HV_FETCH_LVALUE : 0),
369 return hek ? &HeVAL(hek) : NULL;
373 =for apidoc hv_exists_ent
375 Returns a boolean indicating whether the specified hash key exists. C<hash>
376 can be a valid precomputed hash value, or 0 to ask for it to be
383 Perl_hv_exists_ent(pTHX_ HV *hv, SV *keysv, U32 hash)
385 return hv_fetch_common(hv, keysv, NULL, 0, 0, HV_FETCH_ISEXISTS, 0, hash)
389 /* returns an HE * structure with the all fields set */
390 /* note that hent_val will be a mortal sv for MAGICAL hashes */
392 =for apidoc hv_fetch_ent
394 Returns the hash entry which corresponds to the specified key in the hash.
395 C<hash> must be a valid precomputed hash number for the given C<key>, or 0
396 if you want the function to compute it. IF C<lval> is set then the fetch
397 will be part of a store. Make sure the return value is non-null before
398 accessing it. The return value when C<tb> is a tied hash is a pointer to a
399 static location, so be sure to make a copy of the structure if you need to
402 See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
403 information on how to use this function on tied hashes.
409 Perl_hv_fetch_ent(pTHX_ HV *hv, SV *keysv, I32 lval, register U32 hash)
411 return hv_fetch_common(hv, keysv, NULL, 0, 0,
412 (lval ? HV_FETCH_LVALUE : 0), Nullsv, hash);
416 S_hv_fetch_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
417 int flags, int action, SV *val, register U32 hash)
431 if (flags & HVhek_FREEKEY)
433 key = SvPV_const(keysv, klen);
435 is_utf8 = (SvUTF8(keysv) != 0);
437 is_utf8 = ((flags & HVhek_UTF8) ? TRUE : FALSE);
440 xhv = (XPVHV*)SvANY(hv);
442 if (SvRMAGICAL(hv) && !(action & (HV_FETCH_ISSTORE|HV_FETCH_ISEXISTS)))
444 if (mg_find((SV*)hv, PERL_MAGIC_tied) || SvGMAGICAL((SV*)hv)) {
447 /* XXX should be able to skimp on the HE/HEK here when
448 HV_FETCH_JUST_SV is true. */
451 keysv = newSVpvn(key, klen);
456 keysv = newSVsv(keysv);
458 mg_copy((SV*)hv, sv, (char *)keysv, HEf_SVKEY);
460 /* grab a fake HE/HEK pair from the pool or make a new one */
461 entry = PL_hv_fetch_ent_mh;
463 PL_hv_fetch_ent_mh = HeNEXT(entry);
467 Newx(k, HEK_BASESIZE + sizeof(SV*), char);
468 HeKEY_hek(entry) = (HEK*)k;
470 HeNEXT(entry) = Nullhe;
471 HeSVKEY_set(entry, keysv);
473 sv_upgrade(sv, SVt_PVLV);
475 /* so we can free entry when freeing sv */
476 LvTARG(sv) = (SV*)entry;
478 /* XXX remove at some point? */
479 if (flags & HVhek_FREEKEY)
484 #ifdef ENV_IS_CASELESS
485 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
487 for (i = 0; i < klen; ++i)
488 if (isLOWER(key[i])) {
489 /* Would be nice if we had a routine to do the
490 copy and upercase in a single pass through. */
491 const char *nkey = strupr(savepvn(key,klen));
492 /* Note that this fetch is for nkey (the uppercased
493 key) whereas the store is for key (the original) */
494 entry = hv_fetch_common(hv, Nullsv, nkey, klen,
495 HVhek_FREEKEY, /* free nkey */
496 0 /* non-LVAL fetch */,
497 Nullsv /* no value */,
498 0 /* compute hash */);
499 if (!entry && (action & HV_FETCH_LVALUE)) {
500 /* This call will free key if necessary.
501 Do it this way to encourage compiler to tail
503 entry = hv_fetch_common(hv, keysv, key, klen,
504 flags, HV_FETCH_ISSTORE,
507 if (flags & HVhek_FREEKEY)
515 else if (SvRMAGICAL(hv) && (action & HV_FETCH_ISEXISTS)) {
516 if (mg_find((SV*)hv, PERL_MAGIC_tied) || SvGMAGICAL((SV*)hv)) {
517 /* I don't understand why hv_exists_ent has svret and sv,
518 whereas hv_exists only had one. */
519 SV * const svret = sv_newmortal();
522 if (keysv || is_utf8) {
524 keysv = newSVpvn(key, klen);
527 keysv = newSVsv(keysv);
529 mg_copy((SV*)hv, sv, (char *)sv_2mortal(keysv), HEf_SVKEY);
531 mg_copy((SV*)hv, sv, key, klen);
533 if (flags & HVhek_FREEKEY)
535 magic_existspack(svret, mg_find(sv, PERL_MAGIC_tiedelem));
536 /* This cast somewhat evil, but I'm merely using NULL/
537 not NULL to return the boolean exists.
538 And I know hv is not NULL. */
539 return SvTRUE(svret) ? (HE *)hv : NULL;
541 #ifdef ENV_IS_CASELESS
542 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
543 /* XXX This code isn't UTF8 clean. */
544 char * const keysave = (char * const)key;
545 /* Will need to free this, so set FREEKEY flag. */
546 key = savepvn(key,klen);
547 key = (const char*)strupr((char*)key);
552 if (flags & HVhek_FREEKEY) {
555 flags |= HVhek_FREEKEY;
559 else if (action & HV_FETCH_ISSTORE) {
562 hv_magic_check (hv, &needs_copy, &needs_store);
564 const bool save_taint = PL_tainted;
565 if (keysv || is_utf8) {
567 keysv = newSVpvn(key, klen);
571 PL_tainted = SvTAINTED(keysv);
572 keysv = sv_2mortal(newSVsv(keysv));
573 mg_copy((SV*)hv, val, (char*)keysv, HEf_SVKEY);
575 mg_copy((SV*)hv, val, key, klen);
578 TAINT_IF(save_taint);
579 if (!HvARRAY(hv) && !needs_store) {
580 if (flags & HVhek_FREEKEY)
584 #ifdef ENV_IS_CASELESS
585 else if (mg_find((SV*)hv, PERL_MAGIC_env)) {
586 /* XXX This code isn't UTF8 clean. */
587 const char *keysave = key;
588 /* Will need to free this, so set FREEKEY flag. */
589 key = savepvn(key,klen);
590 key = (const char*)strupr((char*)key);
595 if (flags & HVhek_FREEKEY) {
598 flags |= HVhek_FREEKEY;
606 if ((action & (HV_FETCH_LVALUE | HV_FETCH_ISSTORE))
607 #ifdef DYNAMIC_ENV_FETCH /* if it's an %ENV lookup, we may get it on the fly */
608 || (SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env))
613 PERL_HV_ARRAY_ALLOC_BYTES(xhv->xhv_max+1 /* HvMAX(hv)+1 */),
615 HvARRAY(hv) = (HE**)array;
617 #ifdef DYNAMIC_ENV_FETCH
618 else if (action & HV_FETCH_ISEXISTS) {
619 /* for an %ENV exists, if we do an insert it's by a recursive
620 store call, so avoid creating HvARRAY(hv) right now. */
624 /* XXX remove at some point? */
625 if (flags & HVhek_FREEKEY)
633 char * const keysave = (char * const)key;
634 key = (char*)bytes_from_utf8((U8*)key, &klen, &is_utf8);
638 flags &= ~HVhek_UTF8;
639 if (key != keysave) {
640 if (flags & HVhek_FREEKEY)
642 flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
647 PERL_HASH_INTERNAL(hash, key, klen);
648 /* We don't have a pointer to the hv, so we have to replicate the
649 flag into every HEK, so that hv_iterkeysv can see it. */
650 /* And yes, you do need this even though you are not "storing" because
651 you can flip the flags below if doing an lval lookup. (And that
652 was put in to give the semantics Andreas was expecting.) */
653 flags |= HVhek_REHASH;
655 if (keysv && (SvIsCOW_shared_hash(keysv))) {
656 hash = SvSHARED_HASH(keysv);
658 PERL_HASH(hash, key, klen);
662 masked_flags = (flags & HVhek_MASK);
664 #ifdef DYNAMIC_ENV_FETCH
665 if (!HvARRAY(hv)) entry = Null(HE*);
669 entry = (HvARRAY(hv))[hash & (I32) HvMAX(hv)];
671 for (; entry; entry = HeNEXT(entry)) {
672 if (HeHASH(entry) != hash) /* strings can't be equal */
674 if (HeKLEN(entry) != (I32)klen)
676 if (HeKEY(entry) != key && memNE(HeKEY(entry),key,klen)) /* is this it? */
678 if ((HeKFLAGS(entry) ^ masked_flags) & HVhek_UTF8)
681 if (action & (HV_FETCH_LVALUE|HV_FETCH_ISSTORE)) {
682 if (HeKFLAGS(entry) != masked_flags) {
683 /* We match if HVhek_UTF8 bit in our flags and hash key's
684 match. But if entry was set previously with HVhek_WASUTF8
685 and key now doesn't (or vice versa) then we should change
686 the key's flag, as this is assignment. */
687 if (HvSHAREKEYS(hv)) {
688 /* Need to swap the key we have for a key with the flags we
689 need. As keys are shared we can't just write to the
690 flag, so we share the new one, unshare the old one. */
691 HEK *new_hek = share_hek_flags(key, klen, hash,
693 unshare_hek (HeKEY_hek(entry));
694 HeKEY_hek(entry) = new_hek;
696 else if (hv == PL_strtab) {
697 /* PL_strtab is usually the only hash without HvSHAREKEYS,
698 so putting this test here is cheap */
699 if (flags & HVhek_FREEKEY)
701 Perl_croak(aTHX_ S_strtab_error,
702 action & HV_FETCH_LVALUE ? "fetch" : "store");
705 HeKFLAGS(entry) = masked_flags;
706 if (masked_flags & HVhek_ENABLEHVKFLAGS)
709 if (HeVAL(entry) == &PL_sv_placeholder) {
710 /* yes, can store into placeholder slot */
711 if (action & HV_FETCH_LVALUE) {
713 /* This preserves behaviour with the old hv_fetch
714 implementation which at this point would bail out
715 with a break; (at "if we find a placeholder, we
716 pretend we haven't found anything")
718 That break mean that if a placeholder were found, it
719 caused a call into hv_store, which in turn would
720 check magic, and if there is no magic end up pretty
721 much back at this point (in hv_store's code). */
724 /* LVAL fetch which actaully needs a store. */
726 HvPLACEHOLDERS(hv)--;
729 if (val != &PL_sv_placeholder)
730 HvPLACEHOLDERS(hv)--;
733 } else if (action & HV_FETCH_ISSTORE) {
734 SvREFCNT_dec(HeVAL(entry));
737 } else if (HeVAL(entry) == &PL_sv_placeholder) {
738 /* if we find a placeholder, we pretend we haven't found
742 if (flags & HVhek_FREEKEY)
746 #ifdef DYNAMIC_ENV_FETCH /* %ENV lookup? If so, try to fetch the value now */
747 if (!(action & HV_FETCH_ISSTORE)
748 && SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env)) {
750 const char * const env = PerlEnv_ENVgetenv_len(key,&len);
752 sv = newSVpvn(env,len);
754 return hv_fetch_common(hv,keysv,key,klen,flags,HV_FETCH_ISSTORE,sv,
760 if (!entry && SvREADONLY(hv) && !(action & HV_FETCH_ISEXISTS)) {
761 S_hv_notallowed(aTHX_ flags, key, klen,
762 "Attempt to access disallowed key '%"SVf"' in"
763 " a restricted hash");
765 if (!(action & (HV_FETCH_LVALUE|HV_FETCH_ISSTORE))) {
766 /* Not doing some form of store, so return failure. */
767 if (flags & HVhek_FREEKEY)
771 if (action & HV_FETCH_LVALUE) {
774 /* At this point the old hv_fetch code would call to hv_store,
775 which in turn might do some tied magic. So we need to make that
776 magic check happen. */
777 /* gonna assign to this, so it better be there */
778 return hv_fetch_common(hv, keysv, key, klen, flags,
779 HV_FETCH_ISSTORE, val, hash);
780 /* XXX Surely that could leak if the fetch-was-store fails?
781 Just like the hv_fetch. */
785 /* Welcome to hv_store... */
788 /* Not sure if we can get here. I think the only case of oentry being
789 NULL is for %ENV with dynamic env fetch. But that should disappear
790 with magic in the previous code. */
793 PERL_HV_ARRAY_ALLOC_BYTES(xhv->xhv_max+1 /* HvMAX(hv)+1 */),
795 HvARRAY(hv) = (HE**)array;
798 oentry = &(HvARRAY(hv))[hash & (I32) xhv->xhv_max];
801 /* share_hek_flags will do the free for us. This might be considered
804 HeKEY_hek(entry) = share_hek_flags(key, klen, hash, flags);
805 else if (hv == PL_strtab) {
806 /* PL_strtab is usually the only hash without HvSHAREKEYS, so putting
807 this test here is cheap */
808 if (flags & HVhek_FREEKEY)
810 Perl_croak(aTHX_ S_strtab_error,
811 action & HV_FETCH_LVALUE ? "fetch" : "store");
813 else /* gotta do the real thing */
814 HeKEY_hek(entry) = save_hek_flags(key, klen, hash, flags);
816 HeNEXT(entry) = *oentry;
819 if (val == &PL_sv_placeholder)
820 HvPLACEHOLDERS(hv)++;
821 if (masked_flags & HVhek_ENABLEHVKFLAGS)
825 const HE *counter = HeNEXT(entry);
827 xhv->xhv_keys++; /* HvKEYS(hv)++ */
828 if (!counter) { /* initial entry? */
829 xhv->xhv_fill++; /* HvFILL(hv)++ */
830 } else if (xhv->xhv_keys > (IV)xhv->xhv_max) {
832 } else if(!HvREHASH(hv)) {
835 while ((counter = HeNEXT(counter)))
838 if (n_links > HV_MAX_LENGTH_BEFORE_SPLIT) {
839 /* Use only the old HvKEYS(hv) > HvMAX(hv) condition to limit
840 bucket splits on a rehashed hash, as we're not going to
841 split it again, and if someone is lucky (evil) enough to
842 get all the keys in one list they could exhaust our memory
843 as we repeatedly double the number of buckets on every
844 entry. Linear search feels a less worse thing to do. */
854 S_hv_magic_check(pTHX_ HV *hv, bool *needs_copy, bool *needs_store)
856 const MAGIC *mg = SvMAGIC(hv);
860 if (isUPPER(mg->mg_type)) {
862 switch (mg->mg_type) {
863 case 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)
887 if ((SvRMAGICAL(hv) && (mg = mg_find((SV*)hv, PERL_MAGIC_tied)))) {
888 sv = 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, **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, *oent = oents[i];
1434 /* Copy the linked list of entries. */
1435 for (oent = oents[i]; oent; oent = HeNEXT(oent)) {
1436 const U32 hash = HeHASH(oent);
1437 const char * const key = HeKEY(oent);
1438 const STRLEN len = HeKLEN(oent);
1439 const int flags = HeKFLAGS(oent);
1442 HeVAL(ent) = newSVsv(HeVAL(oent));
1444 = shared ? share_hek_flags(key, len, hash, flags)
1445 : save_hek_flags(key, len, hash, flags);
1456 HvFILL(hv) = hv_fill;
1457 HvTOTALKEYS(hv) = HvTOTALKEYS(ohv);
1461 /* Iterate over ohv, copying keys and values one at a time. */
1463 const I32 riter = HvRITER_get(ohv);
1464 HE * const eiter = HvEITER_get(ohv);
1466 /* Can we use fewer buckets? (hv_max is always 2^n-1) */
1467 while (hv_max && hv_max + 1 >= hv_fill * 2)
1468 hv_max = hv_max / 2;
1472 while ((entry = hv_iternext_flags(ohv, 0))) {
1473 hv_store_flags(hv, HeKEY(entry), HeKLEN(entry),
1474 newSVsv(HeVAL(entry)), HeHASH(entry),
1477 HvRITER_set(ohv, riter);
1478 HvEITER_set(ohv, eiter);
1485 Perl_hv_free_ent(pTHX_ HV *hv, register HE *entry)
1492 if (val && isGV(val) && GvCVu(val) && HvNAME_get(hv))
1493 PL_sub_generation++; /* may be deletion of method from stash */
1495 if (HeKLEN(entry) == HEf_SVKEY) {
1496 SvREFCNT_dec(HeKEY_sv(entry));
1497 Safefree(HeKEY_hek(entry));
1499 else if (HvSHAREKEYS(hv))
1500 unshare_hek(HeKEY_hek(entry));
1502 Safefree(HeKEY_hek(entry));
1507 Perl_hv_delayfree_ent(pTHX_ HV *hv, register HE *entry)
1511 /* SvREFCNT_inc to counter the SvREFCNT_dec in hv_free_ent */
1512 sv_2mortal(SvREFCNT_inc(HeVAL(entry))); /* free between statements */
1513 if (HeKLEN(entry) == HEf_SVKEY) {
1514 sv_2mortal(SvREFCNT_inc(HeKEY_sv(entry)));
1516 hv_free_ent(hv, entry);
1520 =for apidoc hv_clear
1522 Clears a hash, making it empty.
1528 Perl_hv_clear(pTHX_ HV *hv)
1531 register XPVHV* xhv;
1535 DEBUG_A(Perl_hv_assert(aTHX_ hv));
1537 xhv = (XPVHV*)SvANY(hv);
1539 if (SvREADONLY(hv) && HvARRAY(hv) != NULL) {
1540 /* restricted hash: convert all keys to placeholders */
1542 for (i = 0; i <= xhv->xhv_max; i++) {
1543 HE *entry = (HvARRAY(hv))[i];
1544 for (; entry; entry = HeNEXT(entry)) {
1545 /* not already placeholder */
1546 if (HeVAL(entry) != &PL_sv_placeholder) {
1547 if (HeVAL(entry) && SvREADONLY(HeVAL(entry))) {
1548 SV* keysv = hv_iterkeysv(entry);
1550 "Attempt to delete readonly key '%"SVf"' from a restricted hash",
1553 SvREFCNT_dec(HeVAL(entry));
1554 HeVAL(entry) = &PL_sv_placeholder;
1555 HvPLACEHOLDERS(hv)++;
1563 HvPLACEHOLDERS_set(hv, 0);
1565 (void)memzero(HvARRAY(hv),
1566 (xhv->xhv_max+1 /* HvMAX(hv)+1 */) * sizeof(HE*));
1571 HvHASKFLAGS_off(hv);
1575 HvEITER_set(hv, NULL);
1580 =for apidoc hv_clear_placeholders
1582 Clears any placeholders from a hash. If a restricted hash has any of its keys
1583 marked as readonly and the key is subsequently deleted, the key is not actually
1584 deleted but is marked by assigning it a value of &PL_sv_placeholder. This tags
1585 it so it will be ignored by future operations such as iterating over the hash,
1586 but will still allow the hash to have a value reassigned to the key at some
1587 future point. This function clears any such placeholder keys from the hash.
1588 See Hash::Util::lock_keys() for an example of its use.
1594 Perl_hv_clear_placeholders(pTHX_ HV *hv)
1597 I32 items = (I32)HvPLACEHOLDERS_get(hv);
1605 /* Loop down the linked list heads */
1607 HE **oentry = &(HvARRAY(hv))[i];
1608 HE *entry = *oentry;
1613 for (; entry; entry = *oentry) {
1614 if (HeVAL(entry) == &PL_sv_placeholder) {
1615 *oentry = HeNEXT(entry);
1616 if (first && !*oentry)
1617 HvFILL(hv)--; /* This linked list is now empty. */
1618 if (HvEITER_get(hv))
1621 hv_free_ent(hv, entry);
1625 HvTOTALKEYS(hv) -= (IV)HvPLACEHOLDERS_get(hv);
1626 if (HvKEYS(hv) == 0)
1627 HvHASKFLAGS_off(hv);
1628 HvPLACEHOLDERS_set(hv, 0);
1632 oentry = &HeNEXT(entry);
1637 /* You can't get here, hence assertion should always fail. */
1638 assert (items == 0);
1643 S_hfreeentries(pTHX_ HV *hv)
1645 register HE **array;
1649 struct xpvhv_aux *iter;
1654 iter = SvOOK(hv) ? HvAUX(hv) : 0;
1658 array = HvARRAY(hv);
1659 /* make everyone else think the array is empty, so that the destructors
1660 * called for freed entries can't recusively mess with us */
1661 HvARRAY(hv) = Null(HE**);
1662 SvFLAGS(hv) &= ~SVf_OOK;
1665 ((XPVHV*) SvANY(hv))->xhv_keys = 0;
1670 register HE * const oentry = entry;
1671 entry = HeNEXT(entry);
1672 hv_free_ent(hv, oentry);
1677 entry = array[riter];
1682 /* Someone attempted to iterate or set the hash name while we had
1683 the array set to 0. */
1684 assert(HvARRAY(hv));
1686 if (HvAUX(hv)->xhv_name)
1687 unshare_hek_or_pvn(HvAUX(hv)->xhv_name, 0, 0, 0);
1688 /* SvOOK_off calls sv_backoff, which isn't correct. */
1690 Safefree(HvARRAY(hv));
1692 SvFLAGS(hv) &= ~SVf_OOK;
1695 /* FIXME - things will still go horribly wrong (or at least leak) if
1696 people attempt to add elements to the hash while we're undef()ing it */
1698 entry = iter->xhv_eiter; /* HvEITER(hv) */
1699 if (entry && HvLAZYDEL(hv)) { /* was deleted earlier? */
1701 hv_free_ent(hv, entry);
1703 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1704 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1705 SvFLAGS(hv) |= SVf_OOK;
1708 HvARRAY(hv) = array;
1712 =for apidoc hv_undef
1720 Perl_hv_undef(pTHX_ HV *hv)
1722 register XPVHV* xhv;
1726 DEBUG_A(Perl_hv_assert(aTHX_ hv));
1727 xhv = (XPVHV*)SvANY(hv);
1729 if ((name = HvNAME_get(hv))) {
1731 hv_delete(PL_stashcache, name, HvNAMELEN_get(hv), G_DISCARD);
1732 Perl_hv_name_set(aTHX_ hv, 0, 0, 0);
1734 SvFLAGS(hv) &= ~SVf_OOK;
1735 Safefree(HvARRAY(hv));
1736 xhv->xhv_max = 7; /* HvMAX(hv) = 7 (it's a normal hash) */
1738 HvPLACEHOLDERS_set(hv, 0);
1744 static struct xpvhv_aux*
1745 S_hv_auxinit(pTHX_ HV *hv) {
1746 struct xpvhv_aux *iter;
1750 Newxz(array, PERL_HV_ARRAY_ALLOC_BYTES(HvMAX(hv) + 1)
1751 + sizeof(struct xpvhv_aux), char);
1753 array = (char *) HvARRAY(hv);
1754 Renew(array, PERL_HV_ARRAY_ALLOC_BYTES(HvMAX(hv) + 1)
1755 + sizeof(struct xpvhv_aux), char);
1757 HvARRAY(hv) = (HE**) array;
1758 /* SvOOK_on(hv) attacks the IV flags. */
1759 SvFLAGS(hv) |= SVf_OOK;
1762 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1763 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1770 =for apidoc hv_iterinit
1772 Prepares a starting point to traverse a hash table. Returns the number of
1773 keys in the hash (i.e. the same as C<HvKEYS(tb)>). The return value is
1774 currently only meaningful for hashes without tie magic.
1776 NOTE: Before version 5.004_65, C<hv_iterinit> used to return the number of
1777 hash buckets that happen to be in use. If you still need that esoteric
1778 value, you can get it through the macro C<HvFILL(tb)>.
1785 Perl_hv_iterinit(pTHX_ HV *hv)
1790 Perl_croak(aTHX_ "Bad hash");
1793 struct xpvhv_aux *iter = HvAUX(hv);
1794 entry = iter->xhv_eiter; /* HvEITER(hv) */
1795 if (entry && HvLAZYDEL(hv)) { /* was deleted earlier? */
1797 hv_free_ent(hv, entry);
1799 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
1800 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1802 S_hv_auxinit(aTHX_ hv);
1805 /* used to be xhv->xhv_fill before 5.004_65 */
1806 return HvTOTALKEYS(hv);
1810 Perl_hv_riter_p(pTHX_ HV *hv) {
1811 struct xpvhv_aux *iter;
1814 Perl_croak(aTHX_ "Bad hash");
1816 iter = SvOOK(hv) ? HvAUX(hv) : S_hv_auxinit(aTHX_ hv);
1817 return &(iter->xhv_riter);
1821 Perl_hv_eiter_p(pTHX_ HV *hv) {
1822 struct xpvhv_aux *iter;
1825 Perl_croak(aTHX_ "Bad hash");
1827 iter = SvOOK(hv) ? HvAUX(hv) : S_hv_auxinit(aTHX_ hv);
1828 return &(iter->xhv_eiter);
1832 Perl_hv_riter_set(pTHX_ HV *hv, I32 riter) {
1833 struct xpvhv_aux *iter;
1836 Perl_croak(aTHX_ "Bad hash");
1844 iter = S_hv_auxinit(aTHX_ hv);
1846 iter->xhv_riter = riter;
1850 Perl_hv_eiter_set(pTHX_ HV *hv, HE *eiter) {
1851 struct xpvhv_aux *iter;
1854 Perl_croak(aTHX_ "Bad hash");
1859 /* 0 is the default so don't go malloc()ing a new structure just to
1864 iter = S_hv_auxinit(aTHX_ hv);
1866 iter->xhv_eiter = eiter;
1870 Perl_hv_name_set(pTHX_ HV *hv, const char *name, I32 len, int flags)
1872 struct xpvhv_aux *iter;
1878 if (iter->xhv_name) {
1879 unshare_hek_or_pvn(iter->xhv_name, 0, 0, 0);
1885 iter = S_hv_auxinit(aTHX_ hv);
1887 PERL_HASH(hash, name, len);
1888 iter->xhv_name = name ? share_hek(name, len, hash) : 0;
1892 =for apidoc hv_iternext
1894 Returns entries from a hash iterator. See C<hv_iterinit>.
1896 You may call C<hv_delete> or C<hv_delete_ent> on the hash entry that the
1897 iterator currently points to, without losing your place or invalidating your
1898 iterator. Note that in this case the current entry is deleted from the hash
1899 with your iterator holding the last reference to it. Your iterator is flagged
1900 to free the entry on the next call to C<hv_iternext>, so you must not discard
1901 your iterator immediately else the entry will leak - call C<hv_iternext> to
1902 trigger the resource deallocation.
1908 Perl_hv_iternext(pTHX_ HV *hv)
1910 return hv_iternext_flags(hv, 0);
1914 =for apidoc hv_iternext_flags
1916 Returns entries from a hash iterator. See C<hv_iterinit> and C<hv_iternext>.
1917 The C<flags> value will normally be zero; if HV_ITERNEXT_WANTPLACEHOLDERS is
1918 set the placeholders keys (for restricted hashes) will be returned in addition
1919 to normal keys. By default placeholders are automatically skipped over.
1920 Currently a placeholder is implemented with a value that is
1921 C<&Perl_sv_placeholder>. Note that the implementation of placeholders and
1922 restricted hashes may change, and the implementation currently is
1923 insufficiently abstracted for any change to be tidy.
1929 Perl_hv_iternext_flags(pTHX_ HV *hv, I32 flags)
1932 register XPVHV* xhv;
1936 struct xpvhv_aux *iter;
1939 Perl_croak(aTHX_ "Bad hash");
1940 xhv = (XPVHV*)SvANY(hv);
1943 /* Too many things (well, pp_each at least) merrily assume that you can
1944 call iv_iternext without calling hv_iterinit, so we'll have to deal
1950 oldentry = entry = iter->xhv_eiter; /* HvEITER(hv) */
1952 if ((mg = SvTIED_mg((SV*)hv, PERL_MAGIC_tied))) {
1953 SV *key = sv_newmortal();
1955 sv_setsv(key, HeSVKEY_force(entry));
1956 SvREFCNT_dec(HeSVKEY(entry)); /* get rid of previous key */
1962 /* one HE per MAGICAL hash */
1963 iter->xhv_eiter = entry = new_HE(); /* HvEITER(hv) = new_HE() */
1965 Newxz(k, HEK_BASESIZE + sizeof(SV*), char);
1967 HeKEY_hek(entry) = hek;
1968 HeKLEN(entry) = HEf_SVKEY;
1970 magic_nextpack((SV*) hv,mg,key);
1972 /* force key to stay around until next time */
1973 HeSVKEY_set(entry, SvREFCNT_inc(key));
1974 return entry; /* beware, hent_val is not set */
1977 SvREFCNT_dec(HeVAL(entry));
1978 Safefree(HeKEY_hek(entry));
1980 iter->xhv_eiter = Null(HE*); /* HvEITER(hv) = Null(HE*) */
1983 #ifdef DYNAMIC_ENV_FETCH /* set up %ENV for iteration */
1984 if (!entry && SvRMAGICAL((SV*)hv) && mg_find((SV*)hv, PERL_MAGIC_env))
1988 /* hv_iterint now ensures this. */
1989 assert (HvARRAY(hv));
1991 /* At start of hash, entry is NULL. */
1994 entry = HeNEXT(entry);
1995 if (!(flags & HV_ITERNEXT_WANTPLACEHOLDERS)) {
1997 * Skip past any placeholders -- don't want to include them in
2000 while (entry && HeVAL(entry) == &PL_sv_placeholder) {
2001 entry = HeNEXT(entry);
2006 /* OK. Come to the end of the current list. Grab the next one. */
2008 iter->xhv_riter++; /* HvRITER(hv)++ */
2009 if (iter->xhv_riter > (I32)xhv->xhv_max /* HvRITER(hv) > HvMAX(hv) */) {
2010 /* There is no next one. End of the hash. */
2011 iter->xhv_riter = -1; /* HvRITER(hv) = -1 */
2014 entry = (HvARRAY(hv))[iter->xhv_riter];
2016 if (!(flags & HV_ITERNEXT_WANTPLACEHOLDERS)) {
2017 /* If we have an entry, but it's a placeholder, don't count it.
2019 while (entry && HeVAL(entry) == &PL_sv_placeholder)
2020 entry = HeNEXT(entry);
2022 /* Will loop again if this linked list starts NULL
2023 (for HV_ITERNEXT_WANTPLACEHOLDERS)
2024 or if we run through it and find only placeholders. */
2027 if (oldentry && HvLAZYDEL(hv)) { /* was deleted earlier? */
2029 hv_free_ent(hv, oldentry);
2032 /*if (HvREHASH(hv) && entry && !HeKREHASH(entry))
2033 PerlIO_printf(PerlIO_stderr(), "Awooga %p %p\n", hv, entry);*/
2035 iter->xhv_eiter = entry; /* HvEITER(hv) = entry */
2040 =for apidoc hv_iterkey
2042 Returns the key from the current position of the hash iterator. See
2049 Perl_hv_iterkey(pTHX_ register HE *entry, I32 *retlen)
2051 if (HeKLEN(entry) == HEf_SVKEY) {
2053 char *p = SvPV(HeKEY_sv(entry), len);
2058 *retlen = HeKLEN(entry);
2059 return HeKEY(entry);
2063 /* unlike hv_iterval(), this always returns a mortal copy of the key */
2065 =for apidoc hv_iterkeysv
2067 Returns the key as an C<SV*> from the current position of the hash
2068 iterator. The return value will always be a mortal copy of the key. Also
2075 Perl_hv_iterkeysv(pTHX_ register HE *entry)
2077 return sv_2mortal(newSVhek(HeKEY_hek(entry)));
2081 =for apidoc hv_iterval
2083 Returns the value from the current position of the hash iterator. See
2090 Perl_hv_iterval(pTHX_ HV *hv, register HE *entry)
2092 if (SvRMAGICAL(hv)) {
2093 if (mg_find((SV*)hv, PERL_MAGIC_tied)) {
2094 SV* sv = sv_newmortal();
2095 if (HeKLEN(entry) == HEf_SVKEY)
2096 mg_copy((SV*)hv, sv, (char*)HeKEY_sv(entry), HEf_SVKEY);
2098 mg_copy((SV*)hv, sv, HeKEY(entry), HeKLEN(entry));
2102 return HeVAL(entry);
2106 =for apidoc hv_iternextsv
2108 Performs an C<hv_iternext>, C<hv_iterkey>, and C<hv_iterval> in one
2115 Perl_hv_iternextsv(pTHX_ HV *hv, char **key, I32 *retlen)
2118 if ( (he = hv_iternext_flags(hv, 0)) == NULL)
2120 *key = hv_iterkey(he, retlen);
2121 return hv_iterval(hv, he);
2125 =for apidoc hv_magic
2127 Adds magic to a hash. See C<sv_magic>.
2133 Perl_hv_magic(pTHX_ HV *hv, GV *gv, int how)
2135 sv_magic((SV*)hv, (SV*)gv, how, Nullch, 0);
2138 #if 0 /* use the macro from hv.h instead */
2141 Perl_sharepvn(pTHX_ const char *sv, I32 len, U32 hash)
2143 return HEK_KEY(share_hek(sv, len, hash));
2148 /* possibly free a shared string if no one has access to it
2149 * len and hash must both be valid for str.
2152 Perl_unsharepvn(pTHX_ const char *str, I32 len, U32 hash)
2154 unshare_hek_or_pvn (NULL, str, len, hash);
2159 Perl_unshare_hek(pTHX_ HEK *hek)
2161 unshare_hek_or_pvn(hek, NULL, 0, 0);
2164 /* possibly free a shared string if no one has access to it
2165 hek if non-NULL takes priority over the other 3, else str, len and hash
2166 are used. If so, len and hash must both be valid for str.
2169 S_unshare_hek_or_pvn(pTHX_ const HEK *hek, const char *str, I32 len, U32 hash)
2171 register XPVHV* xhv;
2173 register HE **oentry;
2176 bool is_utf8 = FALSE;
2178 const char *save = str;
2179 struct shared_he *he = 0;
2182 /* Find the shared he which is just before us in memory. */
2183 he = (struct shared_he *)(((char *)hek)
2184 - STRUCT_OFFSET(struct shared_he,
2187 /* Assert that the caller passed us a genuine (or at least consistent)
2189 assert (he->shared_he_he.hent_hek == hek);
2192 if (he->shared_he_he.hent_val - 1) {
2193 --he->shared_he_he.hent_val;
2194 UNLOCK_STRTAB_MUTEX;
2197 UNLOCK_STRTAB_MUTEX;
2199 hash = HEK_HASH(hek);
2200 } else if (len < 0) {
2201 STRLEN tmplen = -len;
2203 /* See the note in hv_fetch(). --jhi */
2204 str = (char*)bytes_from_utf8((U8*)str, &tmplen, &is_utf8);
2207 k_flags = HVhek_UTF8;
2209 k_flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
2212 /* what follows is the moral equivalent of:
2213 if ((Svp = hv_fetch(PL_strtab, tmpsv, FALSE, hash))) {
2214 if (--*Svp == Nullsv)
2215 hv_delete(PL_strtab, str, len, G_DISCARD, hash);
2217 xhv = (XPVHV*)SvANY(PL_strtab);
2218 /* assert(xhv_array != 0) */
2220 first = oentry = &(HvARRAY(PL_strtab))[hash & (I32) HvMAX(PL_strtab)];
2222 const HE *const he_he = &(he->shared_he_he);
2223 for (entry = *oentry; entry; oentry = &HeNEXT(entry), entry = *oentry) {
2230 const int flags_masked = k_flags & HVhek_MASK;
2231 for (entry = *oentry; entry; oentry = &HeNEXT(entry), entry = *oentry) {
2232 if (HeHASH(entry) != hash) /* strings can't be equal */
2234 if (HeKLEN(entry) != len)
2236 if (HeKEY(entry) != str && memNE(HeKEY(entry),str,len)) /* is this it? */
2238 if (HeKFLAGS(entry) != flags_masked)
2246 if (--HeVAL(entry) == Nullsv) {
2247 *oentry = HeNEXT(entry);
2249 /* There are now no entries in our slot. */
2250 xhv->xhv_fill--; /* HvFILL(hv)-- */
2253 xhv->xhv_keys--; /* HvKEYS(hv)-- */
2257 UNLOCK_STRTAB_MUTEX;
2258 if (!found && ckWARN_d(WARN_INTERNAL))
2259 Perl_warner(aTHX_ packWARN(WARN_INTERNAL),
2260 "Attempt to free non-existent shared string '%s'%s"
2262 hek ? HEK_KEY(hek) : str,
2263 ((k_flags & HVhek_UTF8) ? " (utf8)" : "") pTHX__VALUE);
2264 if (k_flags & HVhek_FREEKEY)
2268 /* get a (constant) string ptr from the global string table
2269 * string will get added if it is not already there.
2270 * len and hash must both be valid for str.
2273 Perl_share_hek(pTHX_ const char *str, I32 len, register U32 hash)
2275 bool is_utf8 = FALSE;
2277 const char *save = str;
2280 STRLEN tmplen = -len;
2282 /* See the note in hv_fetch(). --jhi */
2283 str = (char*)bytes_from_utf8((U8*)str, &tmplen, &is_utf8);
2285 /* If we were able to downgrade here, then than means that we were passed
2286 in a key which only had chars 0-255, but was utf8 encoded. */
2289 /* If we found we were able to downgrade the string to bytes, then
2290 we should flag that it needs upgrading on keys or each. Also flag
2291 that we need share_hek_flags to free the string. */
2293 flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
2296 return share_hek_flags (str, len, hash, flags);
2300 S_share_hek_flags(pTHX_ const char *str, I32 len, register U32 hash, int flags)
2303 register HE **oentry;
2305 const int flags_masked = flags & HVhek_MASK;
2307 /* what follows is the moral equivalent of:
2309 if (!(Svp = hv_fetch(PL_strtab, str, len, FALSE)))
2310 hv_store(PL_strtab, str, len, Nullsv, hash);
2312 Can't rehash the shared string table, so not sure if it's worth
2313 counting the number of entries in the linked list
2315 register XPVHV * const xhv = (XPVHV*)SvANY(PL_strtab);
2316 /* assert(xhv_array != 0) */
2318 oentry = &(HvARRAY(PL_strtab))[hash & (I32) HvMAX(PL_strtab)];
2319 for (entry = *oentry; entry; entry = HeNEXT(entry)) {
2320 if (HeHASH(entry) != hash) /* strings can't be equal */
2322 if (HeKLEN(entry) != len)
2324 if (HeKEY(entry) != str && memNE(HeKEY(entry),str,len)) /* is this it? */
2326 if (HeKFLAGS(entry) != flags_masked)
2332 /* What used to be head of the list.
2333 If this is NULL, then we're the first entry for this slot, which
2334 means we need to increate fill. */
2335 const HE *old_first = *oentry;
2336 struct shared_he *new_entry;
2340 /* We don't actually store a HE from the arena and a regular HEK.
2341 Instead we allocate one chunk of memory big enough for both,
2342 and put the HEK straight after the HE. This way we can find the
2343 HEK directly from the HE.
2346 Newx(k, STRUCT_OFFSET(struct shared_he,
2347 shared_he_hek.hek_key[0]) + len + 2, char);
2348 new_entry = (struct shared_he *)k;
2349 entry = &(new_entry->shared_he_he);
2350 hek = &(new_entry->shared_he_hek);
2352 Copy(str, HEK_KEY(hek), len, char);
2353 HEK_KEY(hek)[len] = 0;
2355 HEK_HASH(hek) = hash;
2356 HEK_FLAGS(hek) = (unsigned char)flags_masked;
2358 /* Still "point" to the HEK, so that other code need not know what
2360 HeKEY_hek(entry) = hek;
2361 HeVAL(entry) = Nullsv;
2362 HeNEXT(entry) = *oentry;
2365 xhv->xhv_keys++; /* HvKEYS(hv)++ */
2366 if (!old_first) { /* initial entry? */
2367 xhv->xhv_fill++; /* HvFILL(hv)++ */
2368 } else if (xhv->xhv_keys > (IV)xhv->xhv_max /* HvKEYS(hv) > HvMAX(hv) */) {
2373 ++HeVAL(entry); /* use value slot as REFCNT */
2374 UNLOCK_STRTAB_MUTEX;
2376 if (flags & HVhek_FREEKEY)
2379 return HeKEY_hek(entry);
2383 Perl_hv_placeholders_p(pTHX_ HV *hv)
2386 MAGIC *mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2389 mg = sv_magicext((SV*)hv, 0, PERL_MAGIC_rhash, 0, 0, 0);
2392 Perl_die(aTHX_ "panic: hv_placeholders_p");
2395 return &(mg->mg_len);
2400 Perl_hv_placeholders_get(pTHX_ HV *hv)
2403 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2405 return mg ? mg->mg_len : 0;
2409 Perl_hv_placeholders_set(pTHX_ HV *hv, I32 ph)
2412 MAGIC * const mg = mg_find((SV*)hv, PERL_MAGIC_rhash);
2417 if (!sv_magicext((SV*)hv, 0, PERL_MAGIC_rhash, 0, 0, ph))
2418 Perl_die(aTHX_ "panic: hv_placeholders_set");
2420 /* else we don't need to add magic to record 0 placeholders. */
2424 =for apidoc hv_assert
2426 Check that a hash is in an internally consistent state.
2432 Perl_hv_assert(pTHX_ HV *hv)
2437 int placeholders = 0;
2440 const I32 riter = HvRITER_get(hv);
2441 HE *eiter = HvEITER_get(hv);
2443 (void)hv_iterinit(hv);
2445 while ((entry = hv_iternext_flags(hv, HV_ITERNEXT_WANTPLACEHOLDERS))) {
2446 /* sanity check the values */
2447 if (HeVAL(entry) == &PL_sv_placeholder) {
2452 /* sanity check the keys */
2453 if (HeSVKEY(entry)) {
2454 /* Don't know what to check on SV keys. */
2455 } else if (HeKUTF8(entry)) {
2457 if (HeKWASUTF8(entry)) {
2458 PerlIO_printf(Perl_debug_log,
2459 "hash key has both WASUFT8 and UTF8: '%.*s'\n",
2460 (int) HeKLEN(entry), HeKEY(entry));
2463 } else if (HeKWASUTF8(entry)) {
2467 if (!SvTIED_mg((SV*)hv, PERL_MAGIC_tied)) {
2468 if (HvUSEDKEYS(hv) != real) {
2469 PerlIO_printf(Perl_debug_log, "Count %d key(s), but hash reports %d\n",
2470 (int) real, (int) HvUSEDKEYS(hv));
2473 if (HvPLACEHOLDERS_get(hv) != placeholders) {
2474 PerlIO_printf(Perl_debug_log,
2475 "Count %d placeholder(s), but hash reports %d\n",
2476 (int) placeholders, (int) HvPLACEHOLDERS_get(hv));
2480 if (withflags && ! HvHASKFLAGS(hv)) {
2481 PerlIO_printf(Perl_debug_log,
2482 "Hash has HASKFLAGS off but I count %d key(s) with flags\n",
2489 HvRITER_set(hv, riter); /* Restore hash iterator state */
2490 HvEITER_set(hv, eiter);
2495 * c-indentation-style: bsd
2497 * indent-tabs-mode: t
2500 * ex: set ts=8 sts=4 sw=4 noet: