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[p5sagit/p5-mst-13.2.git] / hv.h
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a0d0e21e 1/* hv.h
79072805 2 *
4bb101f2 3 * Copyright (C) 1991, 1992, 1993, 1996, 1997, 1998, 1999,
1d325971 4 * 2000, 2001, 2002, 2005, by Larry Wall and others
79072805 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 *
79072805 9 */
10
5cbe4eec 11/* typedefs to eliminate some typing */
79072805 12typedef struct he HE;
ff68c719 13typedef struct hek HEK;
79072805 14
5cbe4eec 15/* entry in hash value chain */
79072805 16struct he {
5cbe4eec 17 HE *hent_next; /* next entry in chain */
18 HEK *hent_hek; /* hash key */
19 SV *hent_val; /* scalar value that was hashed */
bbce6d69 20};
21
5cbe4eec 22/* hash key -- defined separately for use as shared pointer */
ff68c719 23struct hek {
5cbe4eec 24 U32 hek_hash; /* hash of key */
25 I32 hek_len; /* length of hash key */
26 char hek_key[1]; /* variable-length hash key */
e05949c7 27 /* the hash-key is \0-terminated */
1e54db1a 28 /* after the \0 there is a byte for flags, such as whether the key
29 is UTF-8 */
79072805 30};
31
bfcb3514 32
33/* Subject to change.
34 Don't access this directly.
35*/
36struct xpvhv_aux {
7423f6db 37 HEK *xhv_name; /* name, if a symbol table */
bfcb3514 38 HE *xhv_eiter; /* current entry of iterator */
39 I32 xhv_riter; /* current root of iterator */
40};
41
5cbe4eec 42/* hash structure: */
6ee623d5 43/* This structure must match the beginning of struct xpvmg in sv.h. */
79072805 44struct xpvhv {
311a25d9 45 NV xnv_nv; /* numeric value, if any */
463ee0b2 46 STRLEN xhv_fill; /* how full xhv_array currently is */
47 STRLEN xhv_max; /* subscript of last element of xhv_array */
e4305a63 48 union {
311a25d9 49 IV xivu_iv; /* integer value or pv offset */
50 UV xivu_uv;
51 void * xivu_p1;
52 } xiv_u;
79072805 53 MAGIC* xmg_magic; /* magic for scalar array */
54 HV* xmg_stash; /* class package */
79072805 55};
56
311a25d9 57#define xhv_keys xiv_u.xivu_iv
e4305a63 58
c5f87f51 59#if 0
59813432 60typedef struct xpvhv xpvhv_allocated;
9f1501b2 61#else
62typedef struct {
63 STRLEN xhv_fill; /* how full xhv_array currently is */
64 STRLEN xhv_max; /* subscript of last element of xhv_array */
65 union {
311a25d9 66 IV xivu_iv; /* integer value or pv offset */
67 UV xivu_uv;
68 void * xivu_p1;
69 } xiv_u;
9f1501b2 70 MAGIC* xmg_magic; /* magic for scalar array */
71 HV* xmg_stash; /* class package */
72} xpvhv_allocated;
73#endif
e4305a63 74
5cbe4eec 75/* hash a key */
5afd6d42 76/* FYI: This is the "One-at-a-Time" algorithm by Bob Jenkins
77 * from requirements by Colin Plumb.
78 * (http://burtleburtle.net/bob/hash/doobs.html) */
79/* The use of a temporary pointer and the casting games
80 * is needed to serve the dual purposes of
81 * (a) the hashed data being interpreted as "unsigned char" (new since 5.8,
82 * a "char" can be either signed or signed, depending on the compiler)
83 * (b) catering for old code that uses a "char"
830b38bd 84 *
504f80c1 85 * The "hash seed" feature was added in Perl 5.8.1 to perturb the results
86 * to avoid "algorithmic complexity attacks".
830b38bd 87 *
88 * If USE_HASH_SEED is defined, hash randomisation is done by default
89 * If USE_HASH_SEED_EXPLICIT is defined, hash randomisation is done
90 * only if the environment variable PERL_HASH_SEED is set.
91 * For maximal control, one can define PERL_HASH_SEED.
90ce55a1 92 * (see also perl.c:perl_parse()).
5afd6d42 93 */
830b38bd 94#ifndef PERL_HASH_SEED
95# if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT)
96# define PERL_HASH_SEED PL_hash_seed
97# else
98# define PERL_HASH_SEED 0
99# endif
504f80c1 100#endif
bf6bd887 101#define PERL_HASH(hash,str,len) \
102 STMT_START { \
5afd6d42 103 register const char *s_PeRlHaSh_tmp = str; \
104 register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \
bf6bd887 105 register I32 i_PeRlHaSh = len; \
504f80c1 106 register U32 hash_PeRlHaSh = PERL_HASH_SEED; \
a6fe520e 107 while (i_PeRlHaSh--) { \
108 hash_PeRlHaSh += *s_PeRlHaSh++; \
109 hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
110 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
111 } \
112 hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
113 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
4fee5c71 114 (hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
bf6bd887 115 } STMT_END
116
3d78eb94 117/* Only hv.c and mod_perl should be doing this. */
118#ifdef PERL_HASH_INTERNAL_ACCESS
4b5190b5 119#define PERL_HASH_INTERNAL(hash,str,len) \
120 STMT_START { \
121 register const char *s_PeRlHaSh_tmp = str; \
122 register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \
123 register I32 i_PeRlHaSh = len; \
008fb0c0 124 register U32 hash_PeRlHaSh = PL_rehash_seed; \
4b5190b5 125 while (i_PeRlHaSh--) { \
126 hash_PeRlHaSh += *s_PeRlHaSh++; \
127 hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
128 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
129 } \
130 hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
131 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
132 (hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
133 } STMT_END
134#endif
135
954c1994 136/*
ccfc67b7 137=head1 Hash Manipulation Functions
138
954c1994 139=for apidoc AmU||HEf_SVKEY
140This flag, used in the length slot of hash entries and magic structures,
d1be9408 141specifies the structure contains an C<SV*> pointer where a C<char*> pointer
954c1994 142is to be expected. (For information only--not to be used).
143
ccfc67b7 144=head1 Handy Values
145
954c1994 146=for apidoc AmU||Nullhv
147Null HV pointer.
148
ccfc67b7 149=head1 Hash Manipulation Functions
150
954c1994 151=for apidoc Am|char*|HvNAME|HV* stash
152Returns the package name of a stash. See C<SvSTASH>, C<CvSTASH>.
153
154=for apidoc Am|void*|HeKEY|HE* he
155Returns the actual pointer stored in the key slot of the hash entry. The
156pointer may be either C<char*> or C<SV*>, depending on the value of
157C<HeKLEN()>. Can be assigned to. The C<HePV()> or C<HeSVKEY()> macros are
158usually preferable for finding the value of a key.
159
160=for apidoc Am|STRLEN|HeKLEN|HE* he
161If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry
162holds an C<SV*> key. Otherwise, holds the actual length of the key. Can
163be assigned to. The C<HePV()> macro is usually preferable for finding key
164lengths.
165
166=for apidoc Am|SV*|HeVAL|HE* he
167Returns the value slot (type C<SV*>) stored in the hash entry.
168
169=for apidoc Am|U32|HeHASH|HE* he
170Returns the computed hash stored in the hash entry.
171
172=for apidoc Am|char*|HePV|HE* he|STRLEN len
173Returns the key slot of the hash entry as a C<char*> value, doing any
174necessary dereferencing of possibly C<SV*> keys. The length of the string
175is placed in C<len> (this is a macro, so do I<not> use C<&len>). If you do
176not care about what the length of the key is, you may use the global
177variable C<PL_na>, though this is rather less efficient than using a local
178variable. Remember though, that hash keys in perl are free to contain
179embedded nulls, so using C<strlen()> or similar is not a good way to find
180the length of hash keys. This is very similar to the C<SvPV()> macro
181described elsewhere in this document.
182
183=for apidoc Am|SV*|HeSVKEY|HE* he
184Returns the key as an C<SV*>, or C<Nullsv> if the hash entry does not
185contain an C<SV*> key.
186
187=for apidoc Am|SV*|HeSVKEY_force|HE* he
188Returns the key as an C<SV*>. Will create and return a temporary mortal
189C<SV*> if the hash entry contains only a C<char*> key.
190
191=for apidoc Am|SV*|HeSVKEY_set|HE* he|SV* sv
192Sets the key to a given C<SV*>, taking care to set the appropriate flags to
193indicate the presence of an C<SV*> key, and returns the same
194C<SV*>.
195
196=cut
197*/
bf6bd887 198
bf5b86ae 199/* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */
d1be9408 200#define HEf_SVKEY -2 /* hent_key is an SV* */
bf6bd887 201
202
79072805 203#define Nullhv Null(HV*)
339049b0 204#define HvARRAY(hv) (*(HE***)&((hv)->sv_u.svu_array))
79072805 205#define HvFILL(hv) ((XPVHV*) SvANY(hv))->xhv_fill
463ee0b2 206#define HvMAX(hv) ((XPVHV*) SvANY(hv))->xhv_max
b79f7545 207/* This quite intentionally does no flag checking first. That's your
208 responsibility. */
209#define HvAUX(hv) ((struct xpvhv_aux*)&(HvARRAY(hv)[HvMAX(hv)+1]))
bfcb3514 210#define HvRITER(hv) (*Perl_hv_riter_p(aTHX_ (HV*)(hv)))
211#define HvEITER(hv) (*Perl_hv_eiter_p(aTHX_ (HV*)(hv)))
212#define HvRITER_set(hv,r) Perl_hv_riter_set(aTHX_ (HV*)(hv), r)
213#define HvEITER_set(hv,e) Perl_hv_eiter_set(aTHX_ (HV*)(hv), e)
b79f7545 214#define HvRITER_get(hv) (SvOOK(hv) ? HvAUX(hv)->xhv_riter : -1)
215#define HvEITER_get(hv) (SvOOK(hv) ? HvAUX(hv)->xhv_eiter : 0)
7423f6db 216#define HvNAME(hv) HvNAME_get(hv)
bfcb3514 217/* FIXME - all of these should use a UTF8 aware API, which should also involve
218 getting the length. */
9b9d0b15 219/* This macro may go away without notice. */
b79f7545 220#define HvNAME_HEK(hv) (SvOOK(hv) ? HvAUX(hv)->xhv_name : 0)
221#define HvNAME_get(hv) ((SvOOK(hv) && (HvAUX(hv)->xhv_name)) \
222 ? HEK_KEY(HvAUX(hv)->xhv_name) : 0)
223#define HvNAMELEN_get(hv) ((SvOOK(hv) && (HvAUX(hv)->xhv_name)) \
224 ? HEK_LEN(HvAUX(hv)->xhv_name) : 0)
a0d0e21e 225
8aacddc1 226/* the number of keys (including any placeholers) */
227#define XHvTOTALKEYS(xhv) ((xhv)->xhv_keys)
228
8aacddc1 229/*
230 * HvKEYS gets the number of keys that actually exist(), and is provided
231 * for backwards compatibility with old XS code. The core uses HvUSEDKEYS
232 * (keys, excluding placeholdes) and HvTOTALKEYS (including placeholders)
233 */
ca732855 234#define HvKEYS(hv) HvUSEDKEYS(hv)
235#define HvUSEDKEYS(hv) (HvTOTALKEYS(hv) - HvPLACEHOLDERS_get(hv))
8aacddc1 236#define HvTOTALKEYS(hv) XHvTOTALKEYS((XPVHV*) SvANY(hv))
ca732855 237#define HvPLACEHOLDERS(hv) (*Perl_hv_placeholders_p(aTHX_ (HV*)hv))
238#define HvPLACEHOLDERS_get(hv) (SvMAGIC(hv) ? Perl_hv_placeholders_get(aTHX_ (HV*)hv) : 0)
239#define HvPLACEHOLDERS_set(hv,p) Perl_hv_placeholders_set(aTHX_ (HV*)hv, p)
8aacddc1 240
bf6bd887 241#define HvSHAREKEYS(hv) (SvFLAGS(hv) & SVphv_SHAREKEYS)
242#define HvSHAREKEYS_on(hv) (SvFLAGS(hv) |= SVphv_SHAREKEYS)
243#define HvSHAREKEYS_off(hv) (SvFLAGS(hv) &= ~SVphv_SHAREKEYS)
244
19692e8d 245/* This is an optimisation flag. It won't be set if all hash keys have a 0
246 * flag. Currently the only flags relate to utf8.
247 * Hence it won't be set if all keys are 8 bit only. It will be set if any key
248 * is utf8 (including 8 bit keys that were entered as utf8, and need upgrading
249 * when retrieved during iteration. It may still be set when there are no longer
250 * any utf8 keys.
fdcd69b6 251 * See HVhek_ENABLEHVKFLAGS for the trigger.
19692e8d 252 */
253#define HvHASKFLAGS(hv) (SvFLAGS(hv) & SVphv_HASKFLAGS)
254#define HvHASKFLAGS_on(hv) (SvFLAGS(hv) |= SVphv_HASKFLAGS)
255#define HvHASKFLAGS_off(hv) (SvFLAGS(hv) &= ~SVphv_HASKFLAGS)
574c8022 256
bf5b86ae 257#define HvLAZYDEL(hv) (SvFLAGS(hv) & SVphv_LAZYDEL)
258#define HvLAZYDEL_on(hv) (SvFLAGS(hv) |= SVphv_LAZYDEL)
259#define HvLAZYDEL_off(hv) (SvFLAGS(hv) &= ~SVphv_LAZYDEL)
260
4b5190b5 261#define HvREHASH(hv) (SvFLAGS(hv) & SVphv_REHASH)
262#define HvREHASH_on(hv) (SvFLAGS(hv) |= SVphv_REHASH)
263#define HvREHASH_off(hv) (SvFLAGS(hv) &= ~SVphv_REHASH)
264
a0d0e21e 265/* Maybe amagical: */
266/* #define HV_AMAGICmb(hv) (SvFLAGS(hv) & (SVpgv_badAM | SVpgv_AM)) */
267
268#define HV_AMAGIC(hv) (SvFLAGS(hv) & SVpgv_AM)
269#define HV_AMAGIC_on(hv) (SvFLAGS(hv) |= SVpgv_AM)
270#define HV_AMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_AM)
271
272/*
273#define HV_AMAGICbad(hv) (SvFLAGS(hv) & SVpgv_badAM)
274#define HV_badAMAGIC_on(hv) (SvFLAGS(hv) |= SVpgv_badAM)
275#define HV_badAMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_badAM)
276*/
bf6bd887 277
278#define Nullhe Null(HE*)
279#define HeNEXT(he) (he)->hent_next
ff68c719 280#define HeKEY_hek(he) (he)->hent_hek
281#define HeKEY(he) HEK_KEY(HeKEY_hek(he))
bbce6d69 282#define HeKEY_sv(he) (*(SV**)HeKEY(he))
ff68c719 283#define HeKLEN(he) HEK_LEN(HeKEY_hek(he))
da58a35d 284#define HeKUTF8(he) HEK_UTF8(HeKEY_hek(he))
19692e8d 285#define HeKWASUTF8(he) HEK_WASUTF8(HeKEY_hek(he))
4b5190b5 286#define HeKREHASH(he) HEK_REHASH(HeKEY_hek(he))
da58a35d 287#define HeKLEN_UTF8(he) (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he))
19692e8d 288#define HeKFLAGS(he) HEK_FLAGS(HeKEY_hek(he))
bf6bd887 289#define HeVAL(he) (he)->hent_val
ff68c719 290#define HeHASH(he) HEK_HASH(HeKEY_hek(he))
1e422769 291#define HePV(he,lp) ((HeKLEN(he) == HEf_SVKEY) ? \
292 SvPV(HeKEY_sv(he),lp) : \
293 (((lp = HeKLEN(he)) >= 0) ? \
294 HeKEY(he) : Nullch))
295
bbce6d69 296#define HeSVKEY(he) ((HeKEY(he) && \
297 HeKLEN(he) == HEf_SVKEY) ? \
298 HeKEY_sv(he) : Nullsv)
299
300#define HeSVKEY_force(he) (HeKEY(he) ? \
301 ((HeKLEN(he) == HEf_SVKEY) ? \
302 HeKEY_sv(he) : \
79cb57f6 303 sv_2mortal(newSVpvn(HeKEY(he), \
bbce6d69 304 HeKLEN(he)))) : \
3280af22 305 &PL_sv_undef)
1e422769 306#define HeSVKEY_set(he,sv) ((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv))
bbce6d69 307
ff68c719 308#define Nullhek Null(HEK*)
71be2cbc 309#define HEK_BASESIZE STRUCT_OFFSET(HEK, hek_key[0])
ff68c719 310#define HEK_HASH(hek) (hek)->hek_hash
311#define HEK_LEN(hek) (hek)->hek_len
312#define HEK_KEY(hek) (hek)->hek_key
19692e8d 313#define HEK_FLAGS(hek) (*((unsigned char *)(HEK_KEY(hek))+HEK_LEN(hek)+1))
314
315#define HVhek_UTF8 0x01 /* Key is utf8 encoded. */
316#define HVhek_WASUTF8 0x02 /* Key is bytes here, but was supplied as utf8. */
4b5190b5 317#define HVhek_REHASH 0x04 /* This key is in an hv using a custom HASH . */
19692e8d 318#define HVhek_FREEKEY 0x100 /* Internal flag to say key is malloc()ed. */
e16e2ff8 319#define HVhek_PLACEHOLD 0x200 /* Internal flag to create placeholder.
320 * (may change, but Storable is a core module) */
19692e8d 321#define HVhek_MASK 0xFF
322
fdcd69b6 323/* Which flags enable HvHASKFLAGS? Somewhat a hack on a hack, as
324 HVhek_REHASH is only needed because the rehash flag has to be duplicated
325 into all keys as hv_iternext has no access to the hash flags. At this
326 point Storable's tests get upset, because sometimes hashes are "keyed"
327 and sometimes not, depending on the order of data insertion, and whether
328 it triggered rehashing. So currently HVhek_REHAS is exempt.
329*/
330
331#define HVhek_ENABLEHVKFLAGS (HVhek_MASK - HVhek_REHASH)
332
19692e8d 333#define HEK_UTF8(hek) (HEK_FLAGS(hek) & HVhek_UTF8)
334#define HEK_UTF8_on(hek) (HEK_FLAGS(hek) |= HVhek_UTF8)
335#define HEK_UTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_UTF8)
336#define HEK_WASUTF8(hek) (HEK_FLAGS(hek) & HVhek_WASUTF8)
337#define HEK_WASUTF8_on(hek) (HEK_FLAGS(hek) |= HVhek_WASUTF8)
338#define HEK_WASUTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_WASUTF8)
4b5190b5 339#define HEK_REHASH(hek) (HEK_FLAGS(hek) & HVhek_REHASH)
340#define HEK_REHASH_on(hek) (HEK_FLAGS(hek) |= HVhek_REHASH)
d18c6117 341
5cbe4eec 342/* calculate HV array allocation */
36768cf4 343#ifndef PERL_USE_LARGE_HV_ALLOC
344/* Default to allocating the correct size - default to assuming that malloc()
345 is not broken and is efficient at allocating blocks sized at powers-of-two.
346*/
d18c6117 347# define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*))
348#else
349# define MALLOC_OVERHEAD 16
350# define PERL_HV_ARRAY_ALLOC_BYTES(size) \
351 (((size) < 64) \
352 ? (size) * sizeof(HE*) \
353 : (size) * sizeof(HE*) * 2 - MALLOC_OVERHEAD)
354#endif
37d85e3a 355
e16e2ff8 356/* Flags for hv_iternext_flags. */
357#define HV_ITERNEXT_WANTPLACEHOLDERS 0x01 /* Don't skip placeholders. */
358
37d85e3a 359/* available as a function in hv.c */
360#define Perl_sharepvn(sv, len, hash) HEK_KEY(share_hek(sv, len, hash))
361#define sharepvn(sv, len, hash) Perl_sharepvn(sv, len, hash)
bfcb3514 362
363/*
364 * Local variables:
365 * c-indentation-style: bsd
366 * c-basic-offset: 4
367 * indent-tabs-mode: t
368 * End:
369 *
370 * ex: set ts=8 sts=4 sw=4 noet:
371 */