xref: /openbsd/gnu/usr.bin/perl/hv.h (revision d415bd75)
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 /* These control hash traversal randomization and the environment variable PERL_PERTURB_KEYS.
12  * Currently disabling this functionality will break a few tests, but should otherwise work fine.
13  * See perlrun for more details. */
14 
15 #if defined(PERL_PERTURB_KEYS_DISABLED)
16 #   define PL_HASH_RAND_BITS_ENABLED        0
17 #   define PERL_HASH_ITER_BUCKET(iter)      ((iter)->xhv_riter)
18 #else
19 #   define PERL_HASH_RANDOMIZE_KEYS         1
20 #   if defined(PERL_PERTURB_KEYS_RANDOM)
21 #       define PL_HASH_RAND_BITS_ENABLED    1
22 #   elif defined(PERL_PERTURB_KEYS_DETERMINISTIC)
23 #       define PL_HASH_RAND_BITS_ENABLED    2
24 #   else
25 #       define USE_PERL_PERTURB_KEYS        1
26 #       define PL_HASH_RAND_BITS_ENABLED    PL_hash_rand_bits_enabled
27 #   endif
28 #   define PERL_HASH_ITER_BUCKET(iter)      (((iter)->xhv_riter) ^ ((iter)->xhv_rand))
29 #endif
30 
31 #ifdef PERL_USE_UNSHARED_KEYS_IN_LARGE_HASHES
32 #define LARGE_HASH_HEURISTIC(hv,new_max) S_large_hash_heuristic(aTHX_ (hv), (new_max))
33 #else
34 #define LARGE_HASH_HEURISTIC(hv,new_max) 0
35 #endif
36 
37 
38 /* entry in hash value chain */
39 struct he {
40     /* Keep hent_next first in this structure, because sv_free_arenas take
41        advantage of this to share code between the he arenas and the SV
42        body arenas  */
43     HE		*hent_next;	/* next entry in chain */
44     HEK		*hent_hek;	/* hash key */
45     union {
46         SV	*hent_val;	/* scalar value that was hashed */
47         Size_t	hent_refcount;	/* references for this shared hash key */
48     } he_valu;
49 };
50 
51 /* hash key -- defined separately for use as shared pointer */
52 struct hek {
53     U32         hek_hash;        /* computed hash of key */
54     I32         hek_len;        /* length of the hash key */
55     /* Be careful! Sometimes we store a pointer in the hek_key
56      * buffer, which means it must be 8 byte aligned or things
57      * dont work on aligned platforms like HPUX
58      * Also beware, the last byte of the hek_key buffer is a
59      * hidden flags byte about the key. */
60      char       hek_key[1];        /* variable-length hash key */
61     /* the hash-key is \0-terminated */
62     /* after the \0 there is a byte for flags, such as whether the key
63        is UTF-8 or WAS-UTF-8, or an SV */
64 };
65 
66 struct shared_he {
67     struct he shared_he_he;
68     struct hek shared_he_hek;
69 };
70 
71 /* Subject to change.
72    Don't access this directly.
73    Use the funcs in mro_core.c
74 */
75 
76 struct mro_alg {
77     AV *(*resolve)(pTHX_ HV* stash, U32 level);
78     const char *name;
79     U16 length;
80     U16	kflags;	/* For the hash API - set HVhek_UTF8 if name is UTF-8 */
81     U32 hash; /* or 0 */
82 };
83 
84 struct mro_meta {
85     /* a hash holding the different MROs private data.  */
86     HV      *mro_linear_all;
87     /* a pointer directly to the current MROs private data.  If mro_linear_all
88        is NULL, this owns the SV reference, else it is just a pointer to a
89        value stored in and owned by mro_linear_all.  */
90     SV      *mro_linear_current;
91     HV      *mro_nextmethod; /* next::method caching */
92     U32     cache_gen;       /* Bumping this invalidates our method cache */
93     U32     pkg_gen;         /* Bumps when local methods/@ISA change */
94     const struct mro_alg *mro_which; /* which mro alg is in use? */
95     HV      *isa;            /* Everything this class @ISA */
96     HV      *super;          /* SUPER method cache */
97     CV      *destroy;        /* DESTROY method if destroy_gen non-zero */
98     U32     destroy_gen;     /* Generation number of DESTROY cache */
99 };
100 
101 #define MRO_GET_PRIVATE_DATA(smeta, which)		   \
102     (((smeta)->mro_which && (which) == (smeta)->mro_which) \
103      ? (smeta)->mro_linear_current			   \
104      : Perl_mro_get_private_data(aTHX_ (smeta), (which)))
105 
106 /* Subject to change.
107    Don't access this directly.
108 */
109 
110 union _xhvnameu {
111     HEK *xhvnameu_name;		/* When xhv_name_count is 0 */
112     HEK **xhvnameu_names;	/* When xhv_name_count is non-0 */
113 };
114 
115 struct xpvhv_aux {
116     union _xhvnameu xhv_name_u;	/* name, if a symbol table */
117     AV		*xhv_backreferences; /* back references for weak references */
118     HE		*xhv_eiter;	/* current entry of iterator */
119     I32		xhv_riter;	/* current root of iterator */
120 
121 /* Concerning xhv_name_count: When non-zero, xhv_name_u contains a pointer
122  * to an array of HEK pointers, this being the length. The first element is
123  * the name of the stash, which may be NULL. If xhv_name_count is positive,
124  * then *xhv_name is one of the effective names. If xhv_name_count is nega-
125  * tive, then xhv_name_u.xhvnameu_names[1] is the first effective name.
126  */
127     I32		xhv_name_count;
128     struct mro_meta *xhv_mro_meta;
129 #ifdef PERL_HASH_RANDOMIZE_KEYS
130     U32         xhv_rand;       /* random value for hash traversal */
131     U32         xhv_last_rand;  /* last random value for hash traversal,
132                                    used to detect each() after insert for warnings */
133 #endif
134     U32         xhv_aux_flags;      /* assorted extra flags */
135 };
136 
137 #define HvAUXf_SCAN_STASH   0x1   /* stash is being scanned by gv_check */
138 #define HvAUXf_NO_DEREF     0x2   /* @{}, %{} etc (and nomethod) not present */
139 
140 /* hash structure: */
141 /* This structure must match the beginning of struct xpvmg in sv.h. */
142 struct xpvhv {
143     HV*		xmg_stash;	/* class package */
144     union _xmgu	xmg_u;
145     STRLEN      xhv_keys;       /* total keys, including placeholders */
146     STRLEN      xhv_max;        /* subscript of last element of xhv_array */
147 };
148 
149 struct xpvhv_with_aux {
150     HV         *xmg_stash;      /* class package */
151     union _xmgu xmg_u;
152     STRLEN      xhv_keys;       /* total keys, including placeholders */
153     STRLEN      xhv_max;        /* subscript of last element of xhv_array */
154     struct xpvhv_aux xhv_aux;
155 };
156 
157 /*
158 =for apidoc AmnU||HEf_SVKEY
159 This flag, used in the length slot of hash entries and magic structures,
160 specifies the structure contains an C<SV*> pointer where a C<char*> pointer
161 is to be expected.  (For information only--not to be used).
162 
163 =for apidoc ADmnU||Nullhv
164 Null HV pointer.
165 
166 (deprecated - use C<(HV *)NULL> instead)
167 
168 =for apidoc Am|char*|HvNAME|HV* stash
169 Returns the package name of a stash, or C<NULL> if C<stash> isn't a stash.
170 See C<L</SvSTASH>>, C<L</CvSTASH>>.
171 
172 =for apidoc Am|STRLEN|HvNAMELEN|HV *stash
173 Returns the length of the stash's name.
174 
175 Disfavored forms of HvNAME and HvNAMELEN; suppress mention of them
176 =for apidoc Cmh|char*|HvNAME_get|HV* stash
177 =for apidoc Amh|I32|HvNAMELEN_get|HV* stash
178 
179 =for apidoc Am|unsigned char|HvNAMEUTF8|HV *stash
180 Returns true if the name is in UTF-8 encoding.
181 
182 =for apidoc Am|char*|HvENAME|HV* stash
183 Returns the effective name of a stash, or NULL if there is none.  The
184 effective name represents a location in the symbol table where this stash
185 resides.  It is updated automatically when packages are aliased or deleted.
186 A stash that is no longer in the symbol table has no effective name.  This
187 name is preferable to C<HvNAME> for use in MRO linearisations and isa
188 caches.
189 
190 =for apidoc Am|STRLEN|HvENAMELEN|HV *stash
191 Returns the length of the stash's effective name.
192 
193 =for apidoc Am|unsigned char|HvENAMEUTF8|HV *stash
194 Returns true if the effective name is in UTF-8 encoding.
195 
196 =for apidoc Am|void*|HeKEY|HE* he
197 Returns the actual pointer stored in the key slot of the hash entry.  The
198 pointer may be either C<char*> or C<SV*>, depending on the value of
199 C<HeKLEN()>.  Can be assigned to.  The C<HePV()> or C<HeSVKEY()> macros are
200 usually preferable for finding the value of a key.
201 
202 =for apidoc Am|STRLEN|HeKLEN|HE* he
203 If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry
204 holds an C<SV*> key.  Otherwise, holds the actual length of the key.  Can
205 be assigned to.  The C<HePV()> macro is usually preferable for finding key
206 lengths.
207 
208 =for apidoc Am|SV*|HeVAL|HE* he
209 Returns the value slot (type C<SV*>)
210 stored in the hash entry.  Can be assigned
211 to.
212 
213   SV *foo= HeVAL(hv);
214   HeVAL(hv)= sv;
215 
216 
217 =for apidoc Am|U32|HeHASH|HE* he
218 Returns the computed hash stored in the hash entry.
219 
220 =for apidoc Am|char*|HePV|HE* he|STRLEN len
221 Returns the key slot of the hash entry as a C<char*> value, doing any
222 necessary dereferencing of possibly C<SV*> keys.  The length of the string
223 is placed in C<len> (this is a macro, so do I<not> use C<&len>).  If you do
224 not care about what the length of the key is, you may use the global
225 variable C<PL_na>, though this is rather less efficient than using a local
226 variable.  Remember though, that hash keys in perl are free to contain
227 embedded nulls, so using C<strlen()> or similar is not a good way to find
228 the length of hash keys.  This is very similar to the C<SvPV()> macro
229 described elsewhere in this document.  See also C<L</HeUTF8>>.
230 
231 If you are using C<HePV> to get values to pass to C<newSVpvn()> to create a
232 new SV, you should consider using C<newSVhek(HeKEY_hek(he))> as it is more
233 efficient.
234 
235 =for apidoc Am|U32|HeUTF8|HE* he
236 Returns whether the C<char *> value returned by C<HePV> is encoded in UTF-8,
237 doing any necessary dereferencing of possibly C<SV*> keys.  The value returned
238 will be 0 or non-0, not necessarily 1 (or even a value with any low bits set),
239 so B<do not> blindly assign this to a C<bool> variable, as C<bool> may be a
240 typedef for C<char>.
241 
242 =for apidoc Am|SV*|HeSVKEY|HE* he
243 Returns the key as an C<SV*>, or C<NULL> if the hash entry does not
244 contain an C<SV*> key.
245 
246 =for apidoc Am|SV*|HeSVKEY_force|HE* he
247 Returns the key as an C<SV*>.  Will create and return a temporary mortal
248 C<SV*> if the hash entry contains only a C<char*> key.
249 
250 =for apidoc Am|SV*|HeSVKEY_set|HE* he|SV* sv
251 Sets the key to a given C<SV*>, taking care to set the appropriate flags to
252 indicate the presence of an C<SV*> key, and returns the same
253 C<SV*>.
254 
255 =cut
256 */
257 
258 #define PERL_HASH_DEFAULT_HvMAX 7
259 
260 /* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */
261 #define HEf_SVKEY	-2	/* hent_key is an SV* */
262 
263 #ifndef PERL_CORE
264 #  define Nullhv Null(HV*)
265 #endif
266 #define HvARRAY(hv)	((hv)->sv_u.svu_hash)
267 
268 /*
269 
270 =for apidoc Am|STRLEN|HvFILL|HV *const hv
271 
272 Returns the number of hash buckets that happen to be in use.
273 
274 As of perl 5.25 this function is used only for debugging
275 purposes, and the number of used hash buckets is not
276 in any way cached, thus this function can be costly
277 to execute as it must iterate over all the buckets in the
278 hash.
279 
280 =cut
281 
282 */
283 #define HvFILL(hv)	Perl_hv_fill(aTHX_ MUTABLE_HV(hv))
284 #define HvMAX(hv)	((XPVHV*)  SvANY(hv))->xhv_max
285 /* This quite intentionally does no flag checking first. That's your
286    responsibility.  */
287 #define HvAUX(hv)       (&(((struct xpvhv_with_aux*)  SvANY(hv))->xhv_aux))
288 #define HvRITER(hv)	(*Perl_hv_riter_p(aTHX_ MUTABLE_HV(hv)))
289 #define HvEITER(hv)	(*Perl_hv_eiter_p(aTHX_ MUTABLE_HV(hv)))
290 #define HvRITER_set(hv,r)	Perl_hv_riter_set(aTHX_ MUTABLE_HV(hv), r)
291 #define HvEITER_set(hv,e)	Perl_hv_eiter_set(aTHX_ MUTABLE_HV(hv), e)
292 #define HvRITER_get(hv)	(SvOOK(hv) ? HvAUX(hv)->xhv_riter : -1)
293 #define HvEITER_get(hv)	(SvOOK(hv) ? HvAUX(hv)->xhv_eiter : NULL)
294 #define HvRAND_get(hv)	(SvOOK(hv) ? HvAUX(hv)->xhv_rand : 0)
295 #define HvLASTRAND_get(hv)	(SvOOK(hv) ? HvAUX(hv)->xhv_last_rand : 0)
296 
297 #define HvNAME(hv)	HvNAME_get(hv)
298 #define HvNAMELEN(hv)   HvNAMELEN_get(hv)
299 #define HvENAME(hv)	HvENAME_get(hv)
300 #define HvENAMELEN(hv)  HvENAMELEN_get(hv)
301 
302 /* Checking that hv is a valid package stash is the
303    caller's responsibility */
304 #define HvMROMETA(hv) (HvAUX(hv)->xhv_mro_meta \
305                        ? HvAUX(hv)->xhv_mro_meta \
306                        : Perl_mro_meta_init(aTHX_ hv))
307 
308 #define HvNAME_HEK_NN(hv)			  \
309  (						  \
310   HvAUX(hv)->xhv_name_count			  \
311   ? *HvAUX(hv)->xhv_name_u.xhvnameu_names	  \
312   : HvAUX(hv)->xhv_name_u.xhvnameu_name		  \
313  )
314 /* This macro may go away without notice.  */
315 #define HvNAME_HEK(hv) \
316         (SvOOK(hv) && HvAUX(hv)->xhv_name_u.xhvnameu_name ? HvNAME_HEK_NN(hv) : NULL)
317 #define HvNAME_get(hv) \
318         ((SvOOK(hv) && HvAUX(hv)->xhv_name_u.xhvnameu_name && HvNAME_HEK_NN(hv)) \
319                          ? HEK_KEY(HvNAME_HEK_NN(hv)) : NULL)
320 #define HvNAMELEN_get(hv) \
321         ((SvOOK(hv) && HvAUX(hv)->xhv_name_u.xhvnameu_name && HvNAME_HEK_NN(hv)) \
322                                  ? HEK_LEN(HvNAME_HEK_NN(hv)) : 0)
323 #define HvNAMEUTF8(hv) \
324         ((SvOOK(hv) && HvAUX(hv)->xhv_name_u.xhvnameu_name && HvNAME_HEK_NN(hv)) \
325                                  ? HEK_UTF8(HvNAME_HEK_NN(hv)) : 0)
326 #define HvENAME_HEK_NN(hv)                                             \
327  (                                                                      \
328   HvAUX(hv)->xhv_name_count > 0   ? HvAUX(hv)->xhv_name_u.xhvnameu_names[0] : \
329   HvAUX(hv)->xhv_name_count < -1  ? HvAUX(hv)->xhv_name_u.xhvnameu_names[1] : \
330   HvAUX(hv)->xhv_name_count == -1 ? NULL                              : \
331                                     HvAUX(hv)->xhv_name_u.xhvnameu_name \
332  )
333 #define HvENAME_HEK(hv) \
334         (SvOOK(hv) && HvAUX(hv)->xhv_name_u.xhvnameu_name ? HvENAME_HEK_NN(hv) : NULL)
335 #define HvENAME_get(hv) \
336    ((SvOOK(hv) && HvAUX(hv)->xhv_name_u.xhvnameu_name && HvAUX(hv)->xhv_name_count != -1) \
337                          ? HEK_KEY(HvENAME_HEK_NN(hv)) : NULL)
338 #define HvENAMELEN_get(hv) \
339    ((SvOOK(hv) && HvAUX(hv)->xhv_name_u.xhvnameu_name && HvAUX(hv)->xhv_name_count != -1) \
340                                  ? HEK_LEN(HvENAME_HEK_NN(hv)) : 0)
341 #define HvENAMEUTF8(hv) \
342    ((SvOOK(hv) && HvAUX(hv)->xhv_name_u.xhvnameu_name && HvAUX(hv)->xhv_name_count != -1) \
343                                  ? HEK_UTF8(HvENAME_HEK_NN(hv)) : 0)
344 
345 /*
346  * HvKEYS gets the number of keys that actually exist(), and is provided
347  * for backwards compatibility with old XS code. The core uses HvUSEDKEYS
348  * (keys, excluding placeholders) and HvTOTALKEYS (including placeholders)
349  */
350 #define HvKEYS(hv)		HvUSEDKEYS(hv)
351 #define HvUSEDKEYS(hv)		(HvTOTALKEYS(hv) - HvPLACEHOLDERS_get(hv))
352 #define HvTOTALKEYS(hv)         (((XPVHV*) SvANY(hv))->xhv_keys)
353 #define HvPLACEHOLDERS(hv)	(*Perl_hv_placeholders_p(aTHX_ MUTABLE_HV(hv)))
354 #define HvPLACEHOLDERS_get(hv)	(SvMAGIC(hv) ? Perl_hv_placeholders_get(aTHX_ (const HV *)hv) : 0)
355 #define HvPLACEHOLDERS_set(hv,p)	Perl_hv_placeholders_set(aTHX_ MUTABLE_HV(hv), p)
356 
357 /* This (now) flags whether *new* keys in the hash will be allocated from the
358  * shared string table. We have a heuristic to call HvSHAREKEYS_off() if a hash
359  * is "getting large". After which, the first keys in that hash will be from
360  * the shared string table, but subsequent keys will not be.
361  *
362  * If we didn't do this, we'd have to reallocate all keys when we switched this
363  * flag, which would be work for no real gain. */
364 #define HvSHAREKEYS(hv)		(SvFLAGS(hv) & SVphv_SHAREKEYS)
365 #define HvSHAREKEYS_on(hv)	(SvFLAGS(hv) |= SVphv_SHAREKEYS)
366 #define HvSHAREKEYS_off(hv)	(SvFLAGS(hv) &= ~SVphv_SHAREKEYS)
367 
368 /* This is an optimisation flag. It won't be set if all hash keys have a 0
369  * flag. Currently the only flags relate to utf8.
370  * Hence it won't be set if all keys are 8 bit only. It will be set if any key
371  * is utf8 (including 8 bit keys that were entered as utf8, and need upgrading
372  * when retrieved during iteration. It may still be set when there are no longer
373  * any utf8 keys.
374  * See HVhek_ENABLEHVKFLAGS for the trigger.
375  */
376 #define HvHASKFLAGS(hv)		(SvFLAGS(hv) & SVphv_HASKFLAGS)
377 #define HvHASKFLAGS_on(hv)	(SvFLAGS(hv) |= SVphv_HASKFLAGS)
378 #define HvHASKFLAGS_off(hv)	(SvFLAGS(hv) &= ~SVphv_HASKFLAGS)
379 
380 #define HvLAZYDEL(hv)		(SvFLAGS(hv) & SVphv_LAZYDEL)
381 #define HvLAZYDEL_on(hv)	(SvFLAGS(hv) |= SVphv_LAZYDEL)
382 #define HvLAZYDEL_off(hv)	(SvFLAGS(hv) &= ~SVphv_LAZYDEL)
383 
384 #ifndef PERL_CORE
385 #  define Nullhe Null(HE*)
386 #endif
387 #define HeNEXT(he)		(he)->hent_next
388 #define HeKEY_hek(he)		(he)->hent_hek
389 #define HeKEY(he)		HEK_KEY(HeKEY_hek(he))
390 #define HeKEY_sv(he)		(*(SV**)HeKEY(he))
391 #define HeKLEN(he)		HEK_LEN(HeKEY_hek(he))
392 #define HeKUTF8(he)  HEK_UTF8(HeKEY_hek(he))
393 #define HeKWASUTF8(he)  HEK_WASUTF8(HeKEY_hek(he))
394 #define HeKLEN_UTF8(he)  (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he))
395 #define HeKFLAGS(he)  HEK_FLAGS(HeKEY_hek(he))
396 #define HeVAL(he)		(he)->he_valu.hent_val
397 #define HeHASH(he)		HEK_HASH(HeKEY_hek(he))
398 #define HePV(he,lp)		((HeKLEN(he) == HEf_SVKEY) ?		\
399                                  SvPV(HeKEY_sv(he),lp) :		\
400                                  ((lp = HeKLEN(he)), HeKEY(he)))
401 #define HeUTF8(he)		((HeKLEN(he) == HEf_SVKEY) ?		\
402                                  SvUTF8(HeKEY_sv(he)) :			\
403                                  (U32)HeKUTF8(he))
404 
405 #define HeSVKEY(he)		((HeKEY(he) && 				\
406                                   HeKLEN(he) == HEf_SVKEY) ?		\
407                                  HeKEY_sv(he) : NULL)
408 
409 #define HeSVKEY_force(he)	(HeKEY(he) ?				\
410                                  ((HeKLEN(he) == HEf_SVKEY) ?		\
411                                   HeKEY_sv(he) :			\
412                                   newSVpvn_flags(HeKEY(he),		\
413                                                  HeKLEN(he),            \
414                                                  SVs_TEMP |             \
415                                       ( HeKUTF8(he) ? SVf_UTF8 : 0 ))) : \
416                                  &PL_sv_undef)
417 #define HeSVKEY_set(he,sv)	((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv))
418 
419 #ifndef PERL_CORE
420 #  define Nullhek Null(HEK*)
421 #endif
422 #define HEK_BASESIZE		STRUCT_OFFSET(HEK, hek_key[0])
423 #define HEK_HASH(hek)		(hek)->hek_hash
424 #define HEK_LEN(hek)		(hek)->hek_len
425 #define HEK_KEY(hek)		(hek)->hek_key
426 #define HEK_FLAGS(hek)	(*((unsigned char *)(HEK_KEY(hek))+HEK_LEN(hek)+1))
427 
428 #define HVhek_UTF8	0x01 /* Key is utf8 encoded. */
429 #define HVhek_WASUTF8	0x02 /* Key is bytes here, but was supplied as utf8. */
430 #define HVhek_NOTSHARED 0x04 /* This key isn't a shared hash key. */
431 /* the following flags are options for functions, they are not stored in heks */
432 #define HVhek_FREEKEY	0x100 /* Internal flag to say key is Newx()ed.  */
433 #define HVhek_PLACEHOLD	0x200 /* Internal flag to create placeholder.
434                                * (may change, but Storable is a core module) */
435 #define HVhek_KEYCANONICAL 0x400 /* Internal flag - key is in canonical form.
436                                     If the string is UTF-8, it cannot be
437                                     converted to bytes. */
438 #define HVhek_ENABLEHVKFLAGS        (HVhek_UTF8|HVhek_WASUTF8)
439 
440 #define HEK_UTF8(hek)		(HEK_FLAGS(hek) & HVhek_UTF8)
441 #define HEK_UTF8_on(hek)	(HEK_FLAGS(hek) |= HVhek_UTF8)
442 #define HEK_UTF8_off(hek)	(HEK_FLAGS(hek) &= ~HVhek_UTF8)
443 #define HEK_WASUTF8(hek)	(HEK_FLAGS(hek) & HVhek_WASUTF8)
444 #define HEK_WASUTF8_on(hek)	(HEK_FLAGS(hek) |= HVhek_WASUTF8)
445 #define HEK_WASUTF8_off(hek)	(HEK_FLAGS(hek) &= ~HVhek_WASUTF8)
446 
447 /* calculate HV array allocation */
448 #ifndef PERL_USE_LARGE_HV_ALLOC
449 /* Default to allocating the correct size - default to assuming that malloc()
450    is not broken and is efficient at allocating blocks sized at powers-of-two.
451 */
452 #  define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*))
453 #else
454 #  define MALLOC_OVERHEAD 16
455 #  define PERL_HV_ARRAY_ALLOC_BYTES(size) \
456                         (((size) < 64)					\
457                          ? (size) * sizeof(HE*)				\
458                          : (size) * sizeof(HE*) * 2 - MALLOC_OVERHEAD)
459 #endif
460 
461 /* Flags for hv_iternext_flags.  */
462 #define HV_ITERNEXT_WANTPLACEHOLDERS	0x01	/* Don't skip placeholders.  */
463 
464 #define hv_iternext(hv)	hv_iternext_flags(hv, 0)
465 #define hv_magic(hv, gv, how) sv_magic(MUTABLE_SV(hv), MUTABLE_SV(gv), how, NULL, 0)
466 #define hv_undef(hv) Perl_hv_undef_flags(aTHX_ hv, 0)
467 
468 #define Perl_sharepvn(pv, len, hash) HEK_KEY(share_hek(pv, len, hash))
469 #define sharepvn(pv, len, hash)	     Perl_sharepvn(pv, len, hash)
470 
471 #define share_hek_hek(hek)						\
472     (++(((struct shared_he *)(((char *)hek)				\
473                               - STRUCT_OFFSET(struct shared_he,		\
474                                               shared_he_hek)))		\
475         ->shared_he_he.he_valu.hent_refcount),				\
476      hek)
477 
478 #define hv_store_ent(hv, keysv, val, hash)				\
479     ((HE *) hv_common((hv), (keysv), NULL, 0, 0, HV_FETCH_ISSTORE,	\
480                       (val), (hash)))
481 
482 #define hv_exists_ent(hv, keysv, hash)					\
483     cBOOL(hv_common((hv), (keysv), NULL, 0, 0, HV_FETCH_ISEXISTS, 0, (hash)))
484 #define hv_fetch_ent(hv, keysv, lval, hash)				\
485     ((HE *) hv_common((hv), (keysv), NULL, 0, 0,			\
486                       ((lval) ? HV_FETCH_LVALUE : 0), NULL, (hash)))
487 #define hv_delete_ent(hv, key, flags, hash)				\
488     (MUTABLE_SV(hv_common((hv), (key), NULL, 0, 0, (flags) | HV_DELETE,	\
489                           NULL, (hash))))
490 
491 #define hv_store_flags(hv, key, klen, val, hash, flags)			\
492     ((SV**) hv_common((hv), NULL, (key), (klen), (flags),		\
493                       (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV), (val),	\
494                       (hash)))
495 
496 #define hv_store(hv, key, klen, val, hash)				\
497     ((SV**) hv_common_key_len((hv), (key), (klen),			\
498                               (HV_FETCH_ISSTORE|HV_FETCH_JUST_SV),	\
499                               (val), (hash)))
500 
501 
502 
503 #define hv_exists(hv, key, klen)					\
504     cBOOL(hv_common_key_len((hv), (key), (klen), HV_FETCH_ISEXISTS, NULL, 0))
505 
506 #define hv_fetch(hv, key, klen, lval)					\
507     ((SV**) hv_common_key_len((hv), (key), (klen), (lval)		\
508                               ? (HV_FETCH_JUST_SV | HV_FETCH_LVALUE)	\
509                               : HV_FETCH_JUST_SV, NULL, 0))
510 
511 #define hv_delete(hv, key, klen, flags)					\
512     (MUTABLE_SV(hv_common_key_len((hv), (key), (klen),			\
513                                   (flags) | HV_DELETE, NULL, 0)))
514 
515 /* Provide 's' suffix subs for constant strings (and avoid needing to count
516  * chars). See STR_WITH_LEN in handy.h - because these are macros we cant use
517  * STR_WITH_LEN to do the work, we have to unroll it. */
518 #define hv_existss(hv, key) \
519     hv_exists((hv), ASSERT_IS_LITERAL(key), (sizeof(key)-1))
520 
521 #define hv_fetchs(hv, key, lval) \
522     hv_fetch((hv), ASSERT_IS_LITERAL(key), (sizeof(key)-1), (lval))
523 
524 #define hv_deletes(hv, key, flags) \
525     hv_delete((hv), ASSERT_IS_LITERAL(key), (sizeof(key)-1), (flags))
526 
527 #define hv_name_sets(hv, name, flags) \
528     hv_name_set((hv),ASSERT_IS_LITERAL(name),(sizeof(name)-1), flags)
529 
530 #define hv_stores(hv, key, val) \
531     hv_store((hv), ASSERT_IS_LITERAL(key), (sizeof(key)-1), (val), 0)
532 
533 #ifdef PERL_CORE
534 # define hv_storehek(hv, hek, val) \
535     hv_common((hv), NULL, HEK_KEY(hek), HEK_LEN(hek), HEK_UTF8(hek),	\
536               HV_FETCH_ISSTORE|HV_FETCH_JUST_SV, (val), HEK_HASH(hek))
537 # define hv_fetchhek(hv, hek, lval) \
538     ((SV **)								\
539      hv_common((hv), NULL, HEK_KEY(hek), HEK_LEN(hek), HEK_UTF8(hek),	\
540                (lval)							\
541                 ? (HV_FETCH_JUST_SV | HV_FETCH_LVALUE)			\
542                 : HV_FETCH_JUST_SV,					\
543                NULL, HEK_HASH(hek)))
544 # define hv_deletehek(hv, hek, flags) \
545     hv_common((hv), NULL, HEK_KEY(hek), HEK_LEN(hek), HEK_UTF8(hek), \
546               (flags)|HV_DELETE, NULL, HEK_HASH(hek))
547 #define hv_existshek(hv, hek)                                           \
548     cBOOL(hv_common((hv), NULL, HEK_KEY(hek), HEK_LEN(hek), HEK_UTF8(hek), \
549                     HV_FETCH_ISEXISTS, NULL, HEK_HASH(hek)))
550 #endif
551 
552 /* This refcounted he structure is used for storing the hints used for lexical
553    pragmas. Without threads, it's basically struct he + refcount.
554    With threads, life gets more complex as the structure needs to be shared
555    between threads (because it hangs from OPs, which are shared), hence the
556    alternate definition and mutex.  */
557 
558 struct refcounted_he;
559 
560 /* flags for the refcounted_he API */
561 #define REFCOUNTED_HE_KEY_UTF8		0x00000001
562 #define REFCOUNTED_HE_EXISTS		0x00000002
563 
564 #ifdef PERL_CORE
565 
566 /* Gosh. This really isn't a good name any longer.  */
567 struct refcounted_he {
568     struct refcounted_he *refcounted_he_next;	/* next entry in chain */
569 #ifdef USE_ITHREADS
570     U32                   refcounted_he_hash;
571     U32                   refcounted_he_keylen;
572 #else
573     HEK                  *refcounted_he_hek;	/* hint key */
574 #endif
575     union {
576         IV                refcounted_he_u_iv;
577         UV                refcounted_he_u_uv;
578         STRLEN            refcounted_he_u_len;
579         void		 *refcounted_he_u_ptr;	/* Might be useful in future */
580     } refcounted_he_val;
581     U32	                  refcounted_he_refcnt;	/* reference count */
582     /* First byte is flags. Then NUL-terminated value. Then for ithreads,
583        non-NUL terminated key.  */
584     char                  refcounted_he_data[1];
585 };
586 
587 /*
588 =for apidoc m|SV *|refcounted_he_fetch_pvs|const struct refcounted_he *chain|"key"|U32 flags
589 
590 Like L</refcounted_he_fetch_pvn>, but takes a literal string
591 instead of a string/length pair, and no precomputed hash.
592 
593 =cut
594 */
595 
596 #define refcounted_he_fetch_pvs(chain, key, flags) \
597     Perl_refcounted_he_fetch_pvn(aTHX_ chain, STR_WITH_LEN(key), 0, flags)
598 
599 /*
600 =for apidoc m|struct refcounted_he *|refcounted_he_new_pvs|struct refcounted_he *parent|"key"|SV *value|U32 flags
601 
602 Like L</refcounted_he_new_pvn>, but takes a literal string
603 instead of a string/length pair, and no precomputed hash.
604 
605 =cut
606 */
607 
608 #define refcounted_he_new_pvs(parent, key, value, flags) \
609     Perl_refcounted_he_new_pvn(aTHX_ parent, STR_WITH_LEN(key), 0, value, flags)
610 
611 /* Flag bits are HVhek_UTF8, HVhek_WASUTF8, then */
612 #define HVrhek_undef	0x00 /* Value is undef. */
613 #define HVrhek_delete	0x10 /* Value is placeholder - signifies delete. */
614 #define HVrhek_IV	0x20 /* Value is IV. */
615 #define HVrhek_UV	0x30 /* Value is UV. */
616 #define HVrhek_PV	0x40 /* Value is a (byte) string. */
617 #define HVrhek_PV_UTF8	0x50 /* Value is a (utf8) string. */
618 /* Two spare. As these have to live in the optree, you can't store anything
619    interpreter specific, such as SVs. :-( */
620 #define HVrhek_typemask 0x70
621 
622 #ifdef USE_ITHREADS
623 /* A big expression to find the key offset */
624 #define REF_HE_KEY(chain)						\
625         ((((chain->refcounted_he_data[0] & 0x60) == 0x40)		\
626             ? chain->refcounted_he_val.refcounted_he_u_len + 1 : 0)	\
627          + 1 + chain->refcounted_he_data)
628 #endif
629 
630 #  ifdef USE_ITHREADS
631 #    define HINTS_REFCNT_LOCK		MUTEX_LOCK(&PL_hints_mutex)
632 #    define HINTS_REFCNT_UNLOCK		MUTEX_UNLOCK(&PL_hints_mutex)
633 #  else
634 #    define HINTS_REFCNT_LOCK		NOOP
635 #    define HINTS_REFCNT_UNLOCK		NOOP
636 #  endif
637 #endif
638 
639 #ifdef USE_ITHREADS
640 #  define HINTS_REFCNT_INIT		MUTEX_INIT(&PL_hints_mutex)
641 #  define HINTS_REFCNT_TERM		MUTEX_DESTROY(&PL_hints_mutex)
642 #else
643 #  define HINTS_REFCNT_INIT		NOOP
644 #  define HINTS_REFCNT_TERM		NOOP
645 #endif
646 
647 /* Hash actions
648  * Passed in PERL_MAGIC_uvar calls
649  */
650 #define HV_DISABLE_UVAR_XKEY	0x01
651 /* We need to ensure that these don't clash with G_DISCARD, which is 2, as it
652    is documented as being passed to hv_delete().  */
653 #define HV_FETCH_ISSTORE	0x04
654 #define HV_FETCH_ISEXISTS	0x08
655 #define HV_FETCH_LVALUE		0x10
656 #define HV_FETCH_JUST_SV	0x20
657 #define HV_DELETE		0x40
658 #define HV_FETCH_EMPTY_HE	0x80 /* Leave HeVAL null. */
659 
660 /* Must not conflict with HVhek_UTF8 */
661 #define HV_NAME_SETALL		0x02
662 
663 /*
664 =for apidoc newHV
665 
666 Creates a new HV.  The reference count is set to 1.
667 
668 =cut
669 */
670 
671 #define newHV()	MUTABLE_HV(newSV_type(SVt_PVHV))
672 
673 #include "hv_func.h"
674 
675 /*
676  * ex: set ts=8 sts=4 sw=4 et:
677  */
678