xref: /openbsd/gnu/usr.bin/perl/hv.h (revision 404b540a)
1 /*    hv.h
2  *
3  *    Copyright (C) 1991, 1992, 1993, 1996, 1997, 1998, 1999,
4  *    2000, 2001, 2002, 2003, 2005, 2006, 2007, 2008, by Larry Wall and others
5  *
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.
8  *
9  */
10 
11 /* entry in hash value chain */
12 struct he {
13     /* Keep hent_next first in this structure, because sv_free_arenas take
14        advantage of this to share code between the he arenas and the SV
15        body arenas  */
16     HE		*hent_next;	/* next entry in chain */
17     HEK		*hent_hek;	/* hash key */
18     union {
19 	SV	*hent_val;	/* scalar value that was hashed */
20 	Size_t	hent_refcount;	/* references for this shared hash key */
21     } he_valu;
22 };
23 
24 /* hash key -- defined separately for use as shared pointer */
25 struct hek {
26     U32		hek_hash;	/* hash of key */
27     I32		hek_len;	/* length of hash key */
28     char	hek_key[1];	/* variable-length hash key */
29     /* the hash-key is \0-terminated */
30     /* after the \0 there is a byte for flags, such as whether the key
31        is UTF-8 */
32 };
33 
34 struct shared_he {
35     struct he shared_he_he;
36     struct hek shared_he_hek;
37 };
38 
39 /* Subject to change.
40    Don't access this directly.
41    Use the funcs in mro.c
42 */
43 
44 struct mro_alg {
45     AV *(*resolve)(pTHX_ HV* stash, U32 level);
46     const char *name;
47     U16 length;
48     U16	kflags;	/* For the hash API - set HVhek_UTF8 if name is UTF-8 */
49     U32 hash; /* or 0 */
50 };
51 
52 struct mro_meta {
53     /* repurposed as a hash holding the different MROs private data. */
54     AV      *mro_linear_dfs; /* cached dfs @ISA linearization */
55     /* repurposed as a pointer directly to the current MROs private data.  */
56     AV      *mro_linear_c3;  /* cached c3 @ISA linearization */
57     HV      *mro_nextmethod; /* next::method caching */
58     U32     cache_gen;       /* Bumping this invalidates our method cache */
59     U32     pkg_gen;         /* Bumps when local methods/@ISA change */
60     const struct mro_alg *mro_which; /* which mro alg is in use? */
61     HV      *isa;            /* Everything this class @ISA */
62 };
63 
64 #define MRO_GET_PRIVATE_DATA(smeta, which)		   \
65     (((smeta)->mro_which && (which) == (smeta)->mro_which) \
66      ? MUTABLE_SV((smeta)->mro_linear_c3)		   \
67      : Perl_mro_get_private_data(aTHX_ (smeta), (which)))
68 
69 /* Subject to change.
70    Don't access this directly.
71 */
72 
73 struct xpvhv_aux {
74     HEK		*xhv_name;	/* name, if a symbol table */
75     AV		*xhv_backreferences; /* back references for weak references */
76     HE		*xhv_eiter;	/* current entry of iterator */
77     I32		xhv_riter;	/* current root of iterator */
78     struct mro_meta *xhv_mro_meta;
79 };
80 
81 /* hash structure: */
82 /* This structure must match the beginning of struct xpvmg in sv.h. */
83 struct xpvhv {
84     union {
85 	NV	xnv_nv;		/* numeric value, if any */
86 	HV *	xgv_stash;
87 	struct {
88 	    U32	xlow;
89 	    U32	xhigh;
90 	}	xpad_cop_seq;	/* used by pad.c for cop_sequence */
91 	struct {
92 	    U32 xbm_previous;	/* how many characters in string before rare? */
93 	    U8	xbm_flags;
94 	    U8	xbm_rare;	/* rarest character in string */
95 	}	xbm_s;		/* fields from PVBM */
96     }		xnv_u;
97     STRLEN	xhv_fill;	/* how full xhv_array currently is */
98     STRLEN	xhv_max;	/* subscript of last element of xhv_array */
99     union {
100 	IV	xivu_iv;	/* integer value or pv offset */
101 	UV	xivu_uv;
102 	void *	xivu_p1;
103 	I32	xivu_i32;
104 	HEK *	xivu_namehek;
105     }		xiv_u;
106     union {
107 	MAGIC*	xmg_magic;	/* linked list of magicalness */
108 	HV*	xmg_ourstash;	/* Stash for our (when SvPAD_OUR is true) */
109     } xmg_u;
110     HV*		xmg_stash;	/* class package */
111 };
112 
113 #define xhv_keys xiv_u.xivu_iv
114 
115 typedef struct {
116     STRLEN	xhv_fill;	/* how full xhv_array currently is */
117     STRLEN	xhv_max;	/* subscript of last element of xhv_array */
118     union {
119 	IV	xivu_iv;	/* integer value or pv offset */
120 	UV	xivu_uv;
121 	void *	xivu_p1;
122 	I32	xivu_i32;
123 	HEK *	xivu_namehek;
124     }		xiv_u;
125     union {
126 	MAGIC*	xmg_magic;	/* linked list of magicalness */
127 	HV*	xmg_ourstash;	/* Stash for our (when SvPAD_OUR is true) */
128     } xmg_u;
129     HV*		xmg_stash;	/* class package */
130 } xpvhv_allocated;
131 
132 /* hash a key */
133 /* FYI: This is the "One-at-a-Time" algorithm by Bob Jenkins
134  * from requirements by Colin Plumb.
135  * (http://burtleburtle.net/bob/hash/doobs.html) */
136 /* The use of a temporary pointer and the casting games
137  * is needed to serve the dual purposes of
138  * (a) the hashed data being interpreted as "unsigned char" (new since 5.8,
139  *     a "char" can be either signed or unsigned, depending on the compiler)
140  * (b) catering for old code that uses a "char"
141  *
142  * The "hash seed" feature was added in Perl 5.8.1 to perturb the results
143  * to avoid "algorithmic complexity attacks".
144  *
145  * If USE_HASH_SEED is defined, hash randomisation is done by default
146  * If USE_HASH_SEED_EXPLICIT is defined, hash randomisation is done
147  * only if the environment variable PERL_HASH_SEED is set.
148  * For maximal control, one can define PERL_HASH_SEED.
149  * (see also perl.c:perl_parse()).
150  */
151 #ifndef PERL_HASH_SEED
152 #   if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT)
153 #       define PERL_HASH_SEED	PL_hash_seed
154 #   else
155 #       define PERL_HASH_SEED	0
156 #   endif
157 #endif
158 #define PERL_HASH(hash,str,len) \
159      STMT_START	{ \
160 	register const char * const s_PeRlHaSh_tmp = str; \
161 	register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \
162 	register I32 i_PeRlHaSh = len; \
163 	register U32 hash_PeRlHaSh = PERL_HASH_SEED; \
164 	while (i_PeRlHaSh--) { \
165 	    hash_PeRlHaSh += *s_PeRlHaSh++; \
166 	    hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
167 	    hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
168 	} \
169 	hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
170 	hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
171 	(hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
172     } STMT_END
173 
174 /* Only hv.c and mod_perl should be doing this.  */
175 #ifdef PERL_HASH_INTERNAL_ACCESS
176 #define PERL_HASH_INTERNAL(hash,str,len) \
177      STMT_START	{ \
178 	register const char * const s_PeRlHaSh_tmp = str; \
179 	register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \
180 	register I32 i_PeRlHaSh = len; \
181 	register U32 hash_PeRlHaSh = PL_rehash_seed; \
182 	while (i_PeRlHaSh--) { \
183 	    hash_PeRlHaSh += *s_PeRlHaSh++; \
184 	    hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
185 	    hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
186 	} \
187 	hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
188 	hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
189 	(hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
190     } STMT_END
191 #endif
192 
193 /*
194 =head1 Hash Manipulation Functions
195 
196 =for apidoc AmU||HEf_SVKEY
197 This flag, used in the length slot of hash entries and magic structures,
198 specifies the structure contains an C<SV*> pointer where a C<char*> pointer
199 is to be expected. (For information only--not to be used).
200 
201 =head1 Handy Values
202 
203 =for apidoc AmU||Nullhv
204 Null HV pointer.
205 
206 =head1 Hash Manipulation Functions
207 
208 =for apidoc Am|char*|HvNAME|HV* stash
209 Returns the package name of a stash, or NULL if C<stash> isn't a stash.
210 See C<SvSTASH>, C<CvSTASH>.
211 
212 =for apidoc Am|void*|HeKEY|HE* he
213 Returns the actual pointer stored in the key slot of the hash entry. The
214 pointer may be either C<char*> or C<SV*>, depending on the value of
215 C<HeKLEN()>.  Can be assigned to.  The C<HePV()> or C<HeSVKEY()> macros are
216 usually preferable for finding the value of a key.
217 
218 =for apidoc Am|STRLEN|HeKLEN|HE* he
219 If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry
220 holds an C<SV*> key.  Otherwise, holds the actual length of the key.  Can
221 be assigned to. The C<HePV()> macro is usually preferable for finding key
222 lengths.
223 
224 =for apidoc Am|SV*|HeVAL|HE* he
225 Returns the value slot (type C<SV*>) stored in the hash entry.
226 
227 =for apidoc Am|U32|HeHASH|HE* he
228 Returns the computed hash stored in the hash entry.
229 
230 =for apidoc Am|char*|HePV|HE* he|STRLEN len
231 Returns the key slot of the hash entry as a C<char*> value, doing any
232 necessary dereferencing of possibly C<SV*> keys.  The length of the string
233 is placed in C<len> (this is a macro, so do I<not> use C<&len>).  If you do
234 not care about what the length of the key is, you may use the global
235 variable C<PL_na>, though this is rather less efficient than using a local
236 variable.  Remember though, that hash keys in perl are free to contain
237 embedded nulls, so using C<strlen()> or similar is not a good way to find
238 the length of hash keys. This is very similar to the C<SvPV()> macro
239 described elsewhere in this document. See also C<HeUTF8>.
240 
241 If you are using C<HePV> to get values to pass to C<newSVpvn()> to create a
242 new SV, you should consider using C<newSVhek(HeKEY_hek(he))> as it is more
243 efficient.
244 
245 =for apidoc Am|char*|HeUTF8|HE* he|STRLEN len
246 Returns whether the C<char *> value returned by C<HePV> is encoded in UTF-8,
247 doing any necessary dereferencing of possibly C<SV*> keys.  The value returned
248 will be 0 or non-0, not necessarily 1 (or even a value with any low bits set),
249 so B<do not> blindly assign this to a C<bool> variable, as C<bool> may be a
250 typedef for C<char>.
251 
252 =for apidoc Am|SV*|HeSVKEY|HE* he
253 Returns the key as an C<SV*>, or C<NULL> if the hash entry does not
254 contain an C<SV*> key.
255 
256 =for apidoc Am|SV*|HeSVKEY_force|HE* he
257 Returns the key as an C<SV*>.  Will create and return a temporary mortal
258 C<SV*> if the hash entry contains only a C<char*> key.
259 
260 =for apidoc Am|SV*|HeSVKEY_set|HE* he|SV* sv
261 Sets the key to a given C<SV*>, taking care to set the appropriate flags to
262 indicate the presence of an C<SV*> key, and returns the same
263 C<SV*>.
264 
265 =cut
266 */
267 
268 /* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */
269 #define HEf_SVKEY	-2	/* hent_key is an SV* */
270 
271 
272 #define Nullhv Null(HV*)
273 #define HvARRAY(hv)	((hv)->sv_u.svu_hash)
274 #define HvFILL(hv)	((XPVHV*)  SvANY(hv))->xhv_fill
275 #define HvMAX(hv)	((XPVHV*)  SvANY(hv))->xhv_max
276 /* This quite intentionally does no flag checking first. That's your
277    responsibility.  */
278 #define HvAUX(hv)	((struct xpvhv_aux*)&(HvARRAY(hv)[HvMAX(hv)+1]))
279 #define HvRITER(hv)	(*Perl_hv_riter_p(aTHX_ MUTABLE_HV(hv)))
280 #define HvEITER(hv)	(*Perl_hv_eiter_p(aTHX_ MUTABLE_HV(hv)))
281 #define HvRITER_set(hv,r)	Perl_hv_riter_set(aTHX_ MUTABLE_HV(hv), r)
282 #define HvEITER_set(hv,e)	Perl_hv_eiter_set(aTHX_ MUTABLE_HV(hv), e)
283 #define HvRITER_get(hv)	(SvOOK(hv) ? HvAUX(hv)->xhv_riter : -1)
284 #define HvEITER_get(hv)	(SvOOK(hv) ? HvAUX(hv)->xhv_eiter : NULL)
285 #define HvNAME(hv)	HvNAME_get(hv)
286 
287 /* Checking that hv is a valid package stash is the
288    caller's responsibility */
289 #define HvMROMETA(hv) (HvAUX(hv)->xhv_mro_meta \
290                        ? HvAUX(hv)->xhv_mro_meta \
291                        : Perl_mro_meta_init(aTHX_ hv))
292 
293 /* FIXME - all of these should use a UTF8 aware API, which should also involve
294    getting the length. */
295 /* This macro may go away without notice.  */
296 #define HvNAME_HEK(hv) (SvOOK(hv) ? HvAUX(hv)->xhv_name : NULL)
297 #define HvNAME_get(hv)	((SvOOK(hv) && (HvAUX(hv)->xhv_name)) \
298 			 ? HEK_KEY(HvAUX(hv)->xhv_name) : NULL)
299 #define HvNAMELEN_get(hv)	((SvOOK(hv) && (HvAUX(hv)->xhv_name)) \
300 				 ? HEK_LEN(HvAUX(hv)->xhv_name) : 0)
301 
302 /* the number of keys (including any placeholers) */
303 #define XHvTOTALKEYS(xhv)	((xhv)->xhv_keys)
304 
305 /*
306  * HvKEYS gets the number of keys that actually exist(), and is provided
307  * for backwards compatibility with old XS code. The core uses HvUSEDKEYS
308  * (keys, excluding placeholdes) and HvTOTALKEYS (including placeholders)
309  */
310 #define HvKEYS(hv)		HvUSEDKEYS(hv)
311 #define HvUSEDKEYS(hv)		(HvTOTALKEYS(hv) - HvPLACEHOLDERS_get(hv))
312 #define HvTOTALKEYS(hv)		XHvTOTALKEYS((XPVHV*)  SvANY(hv))
313 #define HvPLACEHOLDERS(hv)	(*Perl_hv_placeholders_p(aTHX_ MUTABLE_HV(hv)))
314 #define HvPLACEHOLDERS_get(hv)	(SvMAGIC(hv) ? Perl_hv_placeholders_get(aTHX_ (HV *)hv) : 0)
315 #define HvPLACEHOLDERS_set(hv,p)	Perl_hv_placeholders_set(aTHX_ MUTABLE_HV(hv), p)
316 
317 #define HvSHAREKEYS(hv)		(SvFLAGS(hv) & SVphv_SHAREKEYS)
318 #define HvSHAREKEYS_on(hv)	(SvFLAGS(hv) |= SVphv_SHAREKEYS)
319 #define HvSHAREKEYS_off(hv)	(SvFLAGS(hv) &= ~SVphv_SHAREKEYS)
320 
321 /* This is an optimisation flag. It won't be set if all hash keys have a 0
322  * flag. Currently the only flags relate to utf8.
323  * Hence it won't be set if all keys are 8 bit only. It will be set if any key
324  * is utf8 (including 8 bit keys that were entered as utf8, and need upgrading
325  * when retrieved during iteration. It may still be set when there are no longer
326  * any utf8 keys.
327  * See HVhek_ENABLEHVKFLAGS for the trigger.
328  */
329 #define HvHASKFLAGS(hv)		(SvFLAGS(hv) & SVphv_HASKFLAGS)
330 #define HvHASKFLAGS_on(hv)	(SvFLAGS(hv) |= SVphv_HASKFLAGS)
331 #define HvHASKFLAGS_off(hv)	(SvFLAGS(hv) &= ~SVphv_HASKFLAGS)
332 
333 #define HvLAZYDEL(hv)		(SvFLAGS(hv) & SVphv_LAZYDEL)
334 #define HvLAZYDEL_on(hv)	(SvFLAGS(hv) |= SVphv_LAZYDEL)
335 #define HvLAZYDEL_off(hv)	(SvFLAGS(hv) &= ~SVphv_LAZYDEL)
336 
337 #define HvREHASH(hv)		(SvFLAGS(hv) & SVphv_REHASH)
338 #define HvREHASH_on(hv)		(SvFLAGS(hv) |= SVphv_REHASH)
339 #define HvREHASH_off(hv)	(SvFLAGS(hv) &= ~SVphv_REHASH)
340 
341 #define Nullhe Null(HE*)
342 #define HeNEXT(he)		(he)->hent_next
343 #define HeKEY_hek(he)		(he)->hent_hek
344 #define HeKEY(he)		HEK_KEY(HeKEY_hek(he))
345 #define HeKEY_sv(he)		(*(SV**)HeKEY(he))
346 #define HeKLEN(he)		HEK_LEN(HeKEY_hek(he))
347 #define HeKUTF8(he)  HEK_UTF8(HeKEY_hek(he))
348 #define HeKWASUTF8(he)  HEK_WASUTF8(HeKEY_hek(he))
349 #define HeKREHASH(he)  HEK_REHASH(HeKEY_hek(he))
350 #define HeKLEN_UTF8(he)  (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he))
351 #define HeKFLAGS(he)  HEK_FLAGS(HeKEY_hek(he))
352 #define HeVAL(he)		(he)->he_valu.hent_val
353 #define HeHASH(he)		HEK_HASH(HeKEY_hek(he))
354 #define HePV(he,lp)		((HeKLEN(he) == HEf_SVKEY) ?		\
355 				 SvPV(HeKEY_sv(he),lp) :		\
356 				 ((lp = HeKLEN(he)), HeKEY(he)))
357 #define HeUTF8(he)		((HeKLEN(he) == HEf_SVKEY) ?		\
358 				 SvUTF8(HeKEY_sv(he)) :			\
359 				 (U32)HeKUTF8(he))
360 
361 #define HeSVKEY(he)		((HeKEY(he) && 				\
362 				  HeKLEN(he) == HEf_SVKEY) ?		\
363 				 HeKEY_sv(he) : NULL)
364 
365 #define HeSVKEY_force(he)	(HeKEY(he) ?				\
366 				 ((HeKLEN(he) == HEf_SVKEY) ?		\
367 				  HeKEY_sv(he) :			\
368 				  newSVpvn_flags(HeKEY(he),		\
369 						 HeKLEN(he), SVs_TEMP)) : \
370 				 &PL_sv_undef)
371 #define HeSVKEY_set(he,sv)	((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv))
372 
373 #define Nullhek Null(HEK*)
374 #define HEK_BASESIZE		STRUCT_OFFSET(HEK, hek_key[0])
375 #define HEK_HASH(hek)		(hek)->hek_hash
376 #define HEK_LEN(hek)		(hek)->hek_len
377 #define HEK_KEY(hek)		(hek)->hek_key
378 #define HEK_FLAGS(hek)	(*((unsigned char *)(HEK_KEY(hek))+HEK_LEN(hek)+1))
379 
380 #define HVhek_UTF8	0x01 /* Key is utf8 encoded. */
381 #define HVhek_WASUTF8	0x02 /* Key is bytes here, but was supplied as utf8. */
382 #define HVhek_REHASH	0x04 /* This key is in an hv using a custom HASH . */
383 #define HVhek_UNSHARED	0x08 /* This key isn't a shared hash key. */
384 #define HVhek_FREEKEY	0x100 /* Internal flag to say key is malloc()ed.  */
385 #define HVhek_PLACEHOLD	0x200 /* Internal flag to create placeholder.
386                                * (may change, but Storable is a core module) */
387 #define HVhek_KEYCANONICAL 0x400 /* Internal flag - key is in canonical form.
388 				    If the string is UTF-8, it cannot be
389 				    converted to bytes. */
390 #define HVhek_MASK	0xFF
391 
392 /* Which flags enable HvHASKFLAGS? Somewhat a hack on a hack, as
393    HVhek_REHASH is only needed because the rehash flag has to be duplicated
394    into all keys as hv_iternext has no access to the hash flags. At this
395    point Storable's tests get upset, because sometimes hashes are "keyed"
396    and sometimes not, depending on the order of data insertion, and whether
397    it triggered rehashing. So currently HVhek_REHASH is exempt.
398    Similarly UNSHARED
399 */
400 
401 #define HVhek_ENABLEHVKFLAGS	(HVhek_MASK & ~(HVhek_REHASH|HVhek_UNSHARED))
402 
403 #define HEK_UTF8(hek)		(HEK_FLAGS(hek) & HVhek_UTF8)
404 #define HEK_UTF8_on(hek)	(HEK_FLAGS(hek) |= HVhek_UTF8)
405 #define HEK_UTF8_off(hek)	(HEK_FLAGS(hek) &= ~HVhek_UTF8)
406 #define HEK_WASUTF8(hek)	(HEK_FLAGS(hek) & HVhek_WASUTF8)
407 #define HEK_WASUTF8_on(hek)	(HEK_FLAGS(hek) |= HVhek_WASUTF8)
408 #define HEK_WASUTF8_off(hek)	(HEK_FLAGS(hek) &= ~HVhek_WASUTF8)
409 #define HEK_REHASH(hek)		(HEK_FLAGS(hek) & HVhek_REHASH)
410 #define HEK_REHASH_on(hek)	(HEK_FLAGS(hek) |= HVhek_REHASH)
411 
412 /* calculate HV array allocation */
413 #ifndef PERL_USE_LARGE_HV_ALLOC
414 /* Default to allocating the correct size - default to assuming that malloc()
415    is not broken and is efficient at allocating blocks sized at powers-of-two.
416 */
417 #  define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*))
418 #else
419 #  define MALLOC_OVERHEAD 16
420 #  define PERL_HV_ARRAY_ALLOC_BYTES(size) \
421 			(((size) < 64)					\
422 			 ? (size) * sizeof(HE*)				\
423 			 : (size) * sizeof(HE*) * 2 - MALLOC_OVERHEAD)
424 #endif
425 
426 /* Flags for hv_iternext_flags.  */
427 #define HV_ITERNEXT_WANTPLACEHOLDERS	0x01	/* Don't skip placeholders.  */
428 
429 #define hv_iternext(hv)	hv_iternext_flags(hv, 0)
430 #define hv_magic(hv, gv, how) sv_magic(MUTABLE_SV(hv), MUTABLE_SV(gv), how, NULL, 0)
431 
432 /* available as a function in hv.c */
433 #define Perl_sharepvn(sv, len, hash) HEK_KEY(share_hek(sv, len, hash))
434 #define sharepvn(sv, len, hash)	     Perl_sharepvn(sv, len, hash)
435 
436 #define share_hek_hek(hek)						\
437     (++(((struct shared_he *)(((char *)hek)				\
438 			      - STRUCT_OFFSET(struct shared_he,		\
439 					      shared_he_hek)))		\
440 	->shared_he_he.he_valu.hent_refcount),				\
441      hek)
442 
443 #define hv_store_ent(hv, keysv, val, hash)				\
444     ((HE *) hv_common((hv), (keysv), NULL, 0, 0, HV_FETCH_ISSTORE,	\
445 		      (val), (hash)))
446 
447 #define hv_exists_ent(hv, keysv, hash)					\
448     (hv_common((hv), (keysv), NULL, 0, 0, HV_FETCH_ISEXISTS, 0, (hash))	\
449      ? TRUE : FALSE)
450 #define hv_fetch_ent(hv, keysv, lval, hash)				\
451     ((HE *) hv_common((hv), (keysv), NULL, 0, 0,			\
452 		      ((lval) ? HV_FETCH_LVALUE : 0), NULL, (hash)))
453 #define hv_delete_ent(hv, key, flags, hash)				\
454     (MUTABLE_SV(hv_common((hv), (key), NULL, 0, 0, (flags) | HV_DELETE,	\
455 			  NULL, (hash))))
456 
457 #define hv_store_flags(hv, key, klen, val, hash, flags)			\
458     ((SV**) hv_common((hv), NULL, (key), (klen), (flags),		\
459 		      (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), (val),	\
460 		      (hash)))
461 
462 #define hv_store(hv, key, klen, val, hash)				\
463     ((SV**) hv_common_key_len((hv), (key), (klen),			\
464 			      (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV),	\
465 			      (val), (hash)))
466 
467 #define hv_exists(hv, key, klen)					\
468     (hv_common_key_len((hv), (key), (klen), HV_FETCH_ISEXISTS, NULL, 0) \
469      ? TRUE : FALSE)
470 
471 #define hv_fetch(hv, key, klen, lval)					\
472     ((SV**) hv_common_key_len((hv), (key), (klen), (lval)		\
473 			      ? (HV_FETCH_JUST_SV | HV_FETCH_LVALUE)	\
474 			      : HV_FETCH_JUST_SV, NULL, 0))
475 
476 #define hv_delete(hv, key, klen, flags)					\
477     (MUTABLE_SV(hv_common_key_len((hv), (key), (klen),			\
478 				  (flags) | HV_DELETE, NULL, 0)))
479 
480 /* This refcounted he structure is used for storing the hints used for lexical
481    pragmas. Without threads, it's basically struct he + refcount.
482    With threads, life gets more complex as the structure needs to be shared
483    between threads (because it hangs from OPs, which are shared), hence the
484    alternate definition and mutex.  */
485 
486 struct refcounted_he;
487 
488 #ifdef PERL_CORE
489 
490 /* Gosh. This really isn't a good name any longer.  */
491 struct refcounted_he {
492     struct refcounted_he *refcounted_he_next;	/* next entry in chain */
493 #ifdef USE_ITHREADS
494     U32                   refcounted_he_hash;
495     U32                   refcounted_he_keylen;
496 #else
497     HEK                  *refcounted_he_hek;	/* hint key */
498 #endif
499     union {
500 	IV                refcounted_he_u_iv;
501 	UV                refcounted_he_u_uv;
502 	STRLEN            refcounted_he_u_len;
503 	void		 *refcounted_he_u_ptr;	/* Might be useful in future */
504     } refcounted_he_val;
505     U32	                  refcounted_he_refcnt;	/* reference count */
506     /* First byte is flags. Then NUL-terminated value. Then for ithreads,
507        non-NUL terminated key.  */
508     char                  refcounted_he_data[1];
509 };
510 
511 /* Flag bits are HVhek_UTF8, HVhek_WASUTF8, then */
512 #define HVrhek_undef	0x00 /* Value is undef. */
513 #define HVrhek_delete	0x10 /* Value is placeholder - signifies delete. */
514 #define HVrhek_IV	0x20 /* Value is IV. */
515 #define HVrhek_UV	0x30 /* Value is UV. */
516 #define HVrhek_PV	0x40 /* Value is a (byte) string. */
517 #define HVrhek_PV_UTF8	0x50 /* Value is a (utf8) string. */
518 /* Two spare. As these have to live in the optree, you can't store anything
519    interpreter specific, such as SVs. :-( */
520 #define HVrhek_typemask 0x70
521 
522 #ifdef USE_ITHREADS
523 /* A big expression to find the key offset */
524 #define REF_HE_KEY(chain)						\
525 	((((chain->refcounted_he_data[0] & 0x60) == 0x40)		\
526 	    ? chain->refcounted_he_val.refcounted_he_u_len + 1 : 0)	\
527 	 + 1 + chain->refcounted_he_data)
528 #endif
529 
530 #  ifdef USE_ITHREADS
531 #    define HINTS_REFCNT_LOCK		MUTEX_LOCK(&PL_hints_mutex)
532 #    define HINTS_REFCNT_UNLOCK		MUTEX_UNLOCK(&PL_hints_mutex)
533 #  else
534 #    define HINTS_REFCNT_LOCK		NOOP
535 #    define HINTS_REFCNT_UNLOCK		NOOP
536 #  endif
537 #endif
538 
539 #ifdef USE_ITHREADS
540 #  define HINTS_REFCNT_INIT		MUTEX_INIT(&PL_hints_mutex)
541 #  define HINTS_REFCNT_TERM		MUTEX_DESTROY(&PL_hints_mutex)
542 #else
543 #  define HINTS_REFCNT_INIT		NOOP
544 #  define HINTS_REFCNT_TERM		NOOP
545 #endif
546 
547 /* Hash actions
548  * Passed in PERL_MAGIC_uvar calls
549  */
550 #define HV_DISABLE_UVAR_XKEY	0x01
551 /* We need to ensure that these don't clash with G_DISCARD, which is 2, as it
552    is documented as being passed to hv_delete().  */
553 #define HV_FETCH_ISSTORE	0x04
554 #define HV_FETCH_ISEXISTS	0x08
555 #define HV_FETCH_LVALUE		0x10
556 #define HV_FETCH_JUST_SV	0x20
557 #define HV_DELETE		0x40
558 
559 /*
560 =for apidoc newHV
561 
562 Creates a new HV.  The reference count is set to 1.
563 
564 =cut
565 */
566 
567 #define newHV()	MUTABLE_HV(newSV_type(SVt_PVHV))
568 
569 /*
570  * Local variables:
571  * c-indentation-style: bsd
572  * c-basic-offset: 4
573  * indent-tabs-mode: t
574  * End:
575  *
576  * ex: set ts=8 sts=4 sw=4 noet:
577  */
578